Aggregator

...GILMA INTENSIFYING... ...NOW FORECAST TO BECOME A MAJOR HURRICANE... As of 8:00 AM PDT Wed Aug 21 the center of Gilma was located near 16.0, -122.8 with movement W at 7 mph. The minimum central pressure was 983 mb with maximum sustained winds of about 85 mph.

Issued at 1500 UTC WED AUG 21 2024 000 WTPZ22 KNHC 211440 TCMEP2 HURRICANE GILMA FORECAST/ADVISORY NUMBER 13 NWS NATIONAL HURRICANE CENTER MIAMI FL EP072024 1500 UTC WED AUG 21 2024 HURRICANE CENTER LOCATED NEAR 16.0N 122.8W AT 21/1500Z POSITION ACCURATE WITHIN 30 NM PRESENT MOVEMENT TOWARD THE WEST OR 280 DEGREES AT 6 KT ESTIMATED MINIMUM CENTRAL PRESSURE 983 MB MAX SUSTAINED WINDS 75 KT WITH GUSTS TO 90 KT. 64 KT....... 25NE 20SE 10SW 15NW. 50 KT....... 40NE 40SE 20SW 30NW. 34 KT....... 90NE 100SE 120SW 70NW. 12 FT SEAS..180NE 210SE 150SW 105NW. WINDS AND SEAS VARY GREATLY IN EACH QUADRANT. RADII IN NAUTICAL MILES ARE THE LARGEST RADII EXPECTED ANYWHERE IN THAT QUADRANT. REPEAT...CENTER LOCATED NEAR 16.0N 122.8W AT 21/1500Z AT 21/1200Z CENTER WAS LOCATED NEAR 15.9N 122.5W FORECAST VALID 22/0000Z 16.2N 123.7W MAX WIND 85 KT...GUSTS 105 KT. 64 KT... 20NE 20SE 15SW 15NW. 50 KT... 35NE 35SE 25SW 30NW. 34 KT... 70NE 80SE 90SW 70NW. FORECAST VALID 22/1200Z 16.5N 124.8W MAX WIND 95 KT...GUSTS 115 KT. 64 KT... 25NE 25SE 20SW 20NW. 50 KT... 40NE 35SE 30SW 35NW. 34 KT... 80NE 70SE 70SW 80NW. FORECAST VALID 23/0000Z 16.8N 125.9W MAX WIND 100 KT...GUSTS 120 KT. 64 KT... 25NE 20SE 20SW 25NW. 50 KT... 40NE 35SE 30SW 40NW. 34 KT... 80NE 70SE 70SW 80NW. FORECAST VALID 23/1200Z 16.9N 127.2W MAX WIND 100 KT...GUSTS 120 KT. 64 KT... 25NE 20SE 20SW 25NW. 50 KT... 45NE 40SE 35SW 40NW. 34 KT... 90NE 80SE 80SW 90NW. FORECAST VALID 24/0000Z 17.1N 128.5W MAX WIND 95 KT...GUSTS 115 KT. 50 KT... 45NE 40SE 35SW 40NW. 34 KT... 80NE 70SE 70SW 80NW. FORECAST VALID 24/1200Z 17.3N 130.3W MAX WIND 90 KT...GUSTS 110 KT. 50 KT... 45NE 40SE 35SW 40NW. 34 KT... 80NE 60SE 60SW 80NW. EXTENDED OUTLOOK. NOTE...ERRORS FOR TRACK HAVE AVERAGED NEAR 100 NM ON DAY 4 AND 125 NM ON DAY 5...AND FOR INTENSITY NEAR 15 KT EACH DAY OUTLOOK VALID 25/1200Z 17.5N 133.5W MAX WIND 85 KT...GUSTS 105 KT. 50 KT... 35NE 30SE 30SW 35NW. 34 KT... 80NE 60SE 60SW 80NW. OUTLOOK VALID 26/1200Z 18.0N 137.5W MAX WIND 70 KT...GUSTS 85 KT. 50 KT... 40NE 35SE 30SW 40NW. 34 KT... 80NE 60SE 50SW 80NW. REQUEST FOR 3 HOURLY SHIP REPORTS WITHIN 300 MILES OF 16.0N 122.8W NEXT ADVISORY AT 21/2100Z $$ FORECASTER PAPIN/ALAKA

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0751 AM CDT Wed Aug 21 2024 Valid 211300Z - 221200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER PARTS OF EASTERN MONTANA AND WESTERN NORTH DAKOTA... ...SUMMARY... Severe hail and thunderstorm gusts are most probable over parts of eastern Montana and western North Dakota. ...Synopsis... The CONUS portion of the large-scale, mid/upper-level pattern this period will be characterized by mean troughing over the East and West Coasts, and ridging extending northward over the Great Plains States from a high over west TX. A strong cyclone -- initially centered just south of the AK Panhandle -- is expected to dig south-southeastward, with its 500-mb center moving to around 200 nm west of UIL by 12Z tomorrow. As this process reinforces the mean western trough, a series of mostly low-amplitude shortwave perturbations will eject through the foregoing southwest flow. The best-defined and potentially most important of those perturbations evident in moisture-channel imagery over portions of northern CA, northwestern NV and southeastern OR. This feature should reach southeastern ID and west-central MT around 00Z, before ejecting northeastward across the northern High Plains and losing definition tonight. Meanwhile, in the subtropical easterlies, a shortwave trough will continue to drift westward across parts of Sonora, the Gulf of California, and central/northern Baja. At the surface, 11Z analysis showed rich Gulf-origin moisture still confined near and south of a slowly weakening synoptic front over northern FL, the northern Gulf shelf waters, and southeast to north-central TX. Nonetheless, a plume of mainly 60s F surface dewpoints was analyzed from much of OK north-northwestward across western/central portions of KS, NE and the Dakotas. A lee trough was drawn farther west, over eastern portions of MT/WY/CO. This trough should intensify through the day as ridging aloft shifts somewhat eastward, and southwest flow aloft spreads over more of the High Plains. As part of that process, surface cyclogenesis is expected over the northeastern WY/southeastern MT region, with the resulting low shifting eastward into northwestern SD around 06Z. ...Northern Plains... Widely scattered to scattered thunderstorms are expected to develop initially over the higher terrain of south-central/southwestern MT by midafternoon. In this area, heating of greater elevations preferentially removes MLCINH first, as large-scale lift ahead of the ejecting shortwave begins to move overhead. This activity should move northeastward into parts of central MT atop a boundary layer that is diurnally destabilizing/mixing, yet still favorably moist. Additional thunderstorms may develop by late afternoon near the surface trough, where strong surface heating and the western rim of the corridor of greatest moisture (surface dewpoints commonly in the upper 50s to mid 60s F) will remove capping at lower elevations. Convection of both origins may merge near the trough, over eastern MT. Along the way, activity should produce at least occasional large hail (mainly with any sustained supercells) and damaging gusts. Some aggregation of convection should occur, leading to forward-propagational clustering and increased potential for swath(s) of severe to potentially significant (65+ kt) gusts from late afternoon through much of the evening, as activity moves through a lingering, deep, well-mixed layer left by diurnal heating. A well-heated and deep boundary layer west of the moist plume will support MLCAPE in the 500-1500 J/kg range, with 1000-1500 J/kg DCAPE as well. This will foster high-based convection for the first few hours, with some potential for activity to cluster and become collectively outflow-dominant before reaching the grater moisture. weak low-level winds are expected, beneath 50-80 kt flow in the upper half of the buoyant profile, contributing to favorable deep shear (40-50 kt effective) for supercells, and long, relatively straight hodographs supporting splitting storms and hail potential where convection doesn't produce too much outflow too soon. Thunderstorms will move into larger nominal CAPE and greater near- surface moisture over easternmost MT into western ND, where the moist axis should be found, with MLCAPE of 2000-3000 J/kg. Though MLCINH also will be stronger in the higher-CAPE corridor than farther west, forced ascent that is driven by cold-pool processes should sustain some of the strong-severe convection well into ND this evening. Activity should peak near the moist/buoyancy axis and weaken afterword tonight, as it moves into progressively more-stable low-level profile, both with lower ambient theta-e and nocturnal diabatic cooling/stabilization near the surface. ...Central High Plains... Widely scattered to scattered thunderstorms should develop this afternoon over higher terrain from the Black Hills to the Laramie Range and southward over the Front Range, its foothills, and adjoining ridges such as the Cheyenne Ridge and Palmer Divide. This convection should move east toward the lee trough and low-level moist axis, while crossing over a hot, deeply mixed boundary layer. Isolated severe gusts are expected, and severe hail also may be a concern with relatively discrete cells. While vertical shear will be weaker than farther north, strong veering of flow with height (especially near the trough) should contribute enough deep shear (30-40 kt effective mainly north of I-70) for at least brief supercell potential. Aggregation of outflows may foster one or more eastward-surging clusters into this evening from western KS to central SD, and a relatively concentrated local severe-wind threat will exist in any such cluster. However, guidance is too inconsistent in convective evolution and longevity, and in location/number of such clusters, to assign greater unconditional probabilities within the long "marginal" area at this time. ...Southeastern AZ... Scattered thunderstorms are expected to develop this afternoon, at first over higher terrain then across deserts/valleys as outflow/ differential-heating boundaries develop. With a relatively deep layer of south-southeasterly midlevel flow, activity should move generally northwestward. Though most progs keep the flow aloft modest (15 kt or less), some mesoscale enhancement is possible east of the track of a northwestward-moving MCV -- evident in IR satellite imagery over north-central Sonora. The most intense convection will be capable of isolated severe gusts. Clouds related both to earlier/overnight convection over southern AZ, as well as to activity over MX, are south and west of this region already, portending essentially a full day of insolation over the outlook area. Residual lower-elevation surface dewpoints in the 50s to mid 60s should decrease only slightly through the diurnal heating/mixing cycle, offset to some extent by moist advection. MLCAPE in the 1000-2000 J/kg range should develop through early/mid afternoon, atop the well-mixed subcloud/boundary layer. ..Edwards/Mosier.. 08/21/2024 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0751 AM CDT Wed Aug 21 2024 Valid 211300Z - 221200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER PARTS OF EASTERN MONTANA AND WESTERN NORTH DAKOTA... ...SUMMARY... Severe hail and thunderstorm gusts are most probable over parts of eastern Montana and western North Dakota. ...Synopsis... The CONUS portion of the large-scale, mid/upper-level pattern this period will be characterized by mean troughing over the East and West Coasts, and ridging extending northward over the Great Plains States from a high over west TX. A strong cyclone -- initially centered just south of the AK Panhandle -- is expected to dig south-southeastward, with its 500-mb center moving to around 200 nm west of UIL by 12Z tomorrow. As this process reinforces the mean western trough, a series of mostly low-amplitude shortwave perturbations will eject through the foregoing southwest flow. The best-defined and potentially most important of those perturbations evident in moisture-channel imagery over portions of northern CA, northwestern NV and southeastern OR. This feature should reach southeastern ID and west-central MT around 00Z, before ejecting northeastward across the northern High Plains and losing definition tonight. Meanwhile, in the subtropical easterlies, a shortwave trough will continue to drift westward across parts of Sonora, the Gulf of California, and central/northern Baja. At the surface, 11Z analysis showed rich Gulf-origin moisture still confined near and south of a slowly weakening synoptic front over northern FL, the northern Gulf shelf waters, and southeast to north-central TX. Nonetheless, a plume of mainly 60s F surface dewpoints was analyzed from much of OK north-northwestward across western/central portions of KS, NE and the Dakotas. A lee trough was drawn farther west, over eastern portions of MT/WY/CO. This trough should intensify through the day as ridging aloft shifts somewhat eastward, and southwest flow aloft spreads over more of the High Plains. As part of that process, surface cyclogenesis is expected over the northeastern WY/southeastern MT region, with the resulting low shifting eastward into northwestern SD around 06Z. ...Northern Plains... Widely scattered to scattered thunderstorms are expected to develop initially over the higher terrain of south-central/southwestern MT by midafternoon. In this area, heating of greater elevations preferentially removes MLCINH first, as large-scale lift ahead of the ejecting shortwave begins to move overhead. This activity should move northeastward into parts of central MT atop a boundary layer that is diurnally destabilizing/mixing, yet still favorably moist. Additional thunderstorms may develop by late afternoon near the surface trough, where strong surface heating and the western rim of the corridor of greatest moisture (surface dewpoints commonly in the upper 50s to mid 60s F) will remove capping at lower elevations. Convection of both origins may merge near the trough, over eastern MT. Along the way, activity should produce at least occasional large hail (mainly with any sustained supercells) and damaging gusts. Some aggregation of convection should occur, leading to forward-propagational clustering and increased potential for swath(s) of severe to potentially significant (65+ kt) gusts from late afternoon through much of the evening, as activity moves through a lingering, deep, well-mixed layer left by diurnal heating. A well-heated and deep boundary layer west of the moist plume will support MLCAPE in the 500-1500 J/kg range, with 1000-1500 J/kg DCAPE as well. This will foster high-based convection for the first few hours, with some potential for activity to cluster and become collectively outflow-dominant before reaching the grater moisture. weak low-level winds are expected, beneath 50-80 kt flow in the upper half of the buoyant profile, contributing to favorable deep shear (40-50 kt effective) for supercells, and long, relatively straight hodographs supporting splitting storms and hail potential where convection doesn't produce too much outflow too soon. Thunderstorms will move into larger nominal CAPE and greater near- surface moisture over easternmost MT into western ND, where the moist axis should be found, with MLCAPE of 2000-3000 J/kg. Though MLCINH also will be stronger in the higher-CAPE corridor than farther west, forced ascent that is driven by cold-pool processes should sustain some of the strong-severe convection well into ND this evening. Activity should peak near the moist/buoyancy axis and weaken afterword tonight, as it moves into progressively more-stable low-level profile, both with lower ambient theta-e and nocturnal diabatic cooling/stabilization near the surface. ...Central High Plains... Widely scattered to scattered thunderstorms should develop this afternoon over higher terrain from the Black Hills to the Laramie Range and southward over the Front Range, its foothills, and adjoining ridges such as the Cheyenne Ridge and Palmer Divide. This convection should move east toward the lee trough and low-level moist axis, while crossing over a hot, deeply mixed boundary layer. Isolated severe gusts are expected, and severe hail also may be a concern with relatively discrete cells. While vertical shear will be weaker than farther north, strong veering of flow with height (especially near the trough) should contribute enough deep shear (30-40 kt effective mainly north of I-70) for at least brief supercell potential. Aggregation of outflows may foster one or more eastward-surging clusters into this evening from western KS to central SD, and a relatively concentrated local severe-wind threat will exist in any such cluster. However, guidance is too inconsistent in convective evolution and longevity, and in location/number of such clusters, to assign greater unconditional probabilities within the long "marginal" area at this time. ...Southeastern AZ... Scattered thunderstorms are expected to develop this afternoon, at first over higher terrain then across deserts/valleys as outflow/ differential-heating boundaries develop. With a relatively deep layer of south-southeasterly midlevel flow, activity should move generally northwestward. Though most progs keep the flow aloft modest (15 kt or less), some mesoscale enhancement is possible east of the track of a northwestward-moving MCV -- evident in IR satellite imagery over north-central Sonora. The most intense convection will be capable of isolated severe gusts. Clouds related both to earlier/overnight convection over southern AZ, as well as to activity over MX, are south and west of this region already, portending essentially a full day of insolation over the outlook area. Residual lower-elevation surface dewpoints in the 50s to mid 60s should decrease only slightly through the diurnal heating/mixing cycle, offset to some extent by moist advection. MLCAPE in the 1000-2000 J/kg range should develop through early/mid afternoon, atop the well-mixed subcloud/boundary layer. ..Edwards/Mosier.. 08/21/2024 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0751 AM CDT Wed Aug 21 2024 Valid 211300Z - 221200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER PARTS OF EASTERN MONTANA AND WESTERN NORTH DAKOTA... ...SUMMARY... Severe hail and thunderstorm gusts are most probable over parts of eastern Montana and western North Dakota. ...Synopsis... The CONUS portion of the large-scale, mid/upper-level pattern this period will be characterized by mean troughing over the East and West Coasts, and ridging extending northward over the Great Plains States from a high over west TX. A strong cyclone -- initially centered just south of the AK Panhandle -- is expected to dig south-southeastward, with its 500-mb center moving to around 200 nm west of UIL by 12Z tomorrow. As this process reinforces the mean western trough, a series of mostly low-amplitude shortwave perturbations will eject through the foregoing southwest flow. The best-defined and potentially most important of those perturbations evident in moisture-channel imagery over portions of northern CA, northwestern NV and southeastern OR. This feature should reach southeastern ID and west-central MT around 00Z, before ejecting northeastward across the northern High Plains and losing definition tonight. Meanwhile, in the subtropical easterlies, a shortwave trough will continue to drift westward across parts of Sonora, the Gulf of California, and central/northern Baja. At the surface, 11Z analysis showed rich Gulf-origin moisture still confined near and south of a slowly weakening synoptic front over northern FL, the northern Gulf shelf waters, and southeast to north-central TX. Nonetheless, a plume of mainly 60s F surface dewpoints was analyzed from much of OK north-northwestward across western/central portions of KS, NE and the Dakotas. A lee trough was drawn farther west, over eastern portions of MT/WY/CO. This trough should intensify through the day as ridging aloft shifts somewhat eastward, and southwest flow aloft spreads over more of the High Plains. As part of that process, surface cyclogenesis is expected over the northeastern WY/southeastern MT region, with the resulting low shifting eastward into northwestern SD around 06Z. ...Northern Plains... Widely scattered to scattered thunderstorms are expected to develop initially over the higher terrain of south-central/southwestern MT by midafternoon. In this area, heating of greater elevations preferentially removes MLCINH first, as large-scale lift ahead of the ejecting shortwave begins to move overhead. This activity should move northeastward into parts of central MT atop a boundary layer that is diurnally destabilizing/mixing, yet still favorably moist. Additional thunderstorms may develop by late afternoon near the surface trough, where strong surface heating and the western rim of the corridor of greatest moisture (surface dewpoints commonly in the upper 50s to mid 60s F) will remove capping at lower elevations. Convection of both origins may merge near the trough, over eastern MT. Along the way, activity should produce at least occasional large hail (mainly with any sustained supercells) and damaging gusts. Some aggregation of convection should occur, leading to forward-propagational clustering and increased potential for swath(s) of severe to potentially significant (65+ kt) gusts from late afternoon through much of the evening, as activity moves through a lingering, deep, well-mixed layer left by diurnal heating. A well-heated and deep boundary layer west of the moist plume will support MLCAPE in the 500-1500 J/kg range, with 1000-1500 J/kg DCAPE as well. This will foster high-based convection for the first few hours, with some potential for activity to cluster and become collectively outflow-dominant before reaching the grater moisture. weak low-level winds are expected, beneath 50-80 kt flow in the upper half of the buoyant profile, contributing to favorable deep shear (40-50 kt effective) for supercells, and long, relatively straight hodographs supporting splitting storms and hail potential where convection doesn't produce too much outflow too soon. Thunderstorms will move into larger nominal CAPE and greater near- surface moisture over easternmost MT into western ND, where the moist axis should be found, with MLCAPE of 2000-3000 J/kg. Though MLCINH also will be stronger in the higher-CAPE corridor than farther west, forced ascent that is driven by cold-pool processes should sustain some of the strong-severe convection well into ND this evening. Activity should peak near the moist/buoyancy axis and weaken afterword tonight, as it moves into progressively more-stable low-level profile, both with lower ambient theta-e and nocturnal diabatic cooling/stabilization near the surface. ...Central High Plains... Widely scattered to scattered thunderstorms should develop this afternoon over higher terrain from the Black Hills to the Laramie Range and southward over the Front Range, its foothills, and adjoining ridges such as the Cheyenne Ridge and Palmer Divide. This convection should move east toward the lee trough and low-level moist axis, while crossing over a hot, deeply mixed boundary layer. Isolated severe gusts are expected, and severe hail also may be a concern with relatively discrete cells. While vertical shear will be weaker than farther north, strong veering of flow with height (especially near the trough) should contribute enough deep shear (30-40 kt effective mainly north of I-70) for at least brief supercell potential. Aggregation of outflows may foster one or more eastward-surging clusters into this evening from western KS to central SD, and a relatively concentrated local severe-wind threat will exist in any such cluster. However, guidance is too inconsistent in convective evolution and longevity, and in location/number of such clusters, to assign greater unconditional probabilities within the long "marginal" area at this time. ...Southeastern AZ... Scattered thunderstorms are expected to develop this afternoon, at first over higher terrain then across deserts/valleys as outflow/ differential-heating boundaries develop. With a relatively deep layer of south-southeasterly midlevel flow, activity should move generally northwestward. Though most progs keep the flow aloft modest (15 kt or less), some mesoscale enhancement is possible east of the track of a northwestward-moving MCV -- evident in IR satellite imagery over north-central Sonora. The most intense convection will be capable of isolated severe gusts. Clouds related both to earlier/overnight convection over southern AZ, as well as to activity over MX, are south and west of this region already, portending essentially a full day of insolation over the outlook area. Residual lower-elevation surface dewpoints in the 50s to mid 60s should decrease only slightly through the diurnal heating/mixing cycle, offset to some extent by moist advection. MLCAPE in the 1000-2000 J/kg range should develop through early/mid afternoon, atop the well-mixed subcloud/boundary layer. ..Edwards/Mosier.. 08/21/2024 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0751 AM CDT Wed Aug 21 2024 Valid 211300Z - 221200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER PARTS OF EASTERN MONTANA AND WESTERN NORTH DAKOTA... ...SUMMARY... Severe hail and thunderstorm gusts are most probable over parts of eastern Montana and western North Dakota. ...Synopsis... The CONUS portion of the large-scale, mid/upper-level pattern this period will be characterized by mean troughing over the East and West Coasts, and ridging extending northward over the Great Plains States from a high over west TX. A strong cyclone -- initially centered just south of the AK Panhandle -- is expected to dig south-southeastward, with its 500-mb center moving to around 200 nm west of UIL by 12Z tomorrow. As this process reinforces the mean western trough, a series of mostly low-amplitude shortwave perturbations will eject through the foregoing southwest flow. The best-defined and potentially most important of those perturbations evident in moisture-channel imagery over portions of northern CA, northwestern NV and southeastern OR. This feature should reach southeastern ID and west-central MT around 00Z, before ejecting northeastward across the northern High Plains and losing definition tonight. Meanwhile, in the subtropical easterlies, a shortwave trough will continue to drift westward across parts of Sonora, the Gulf of California, and central/northern Baja. At the surface, 11Z analysis showed rich Gulf-origin moisture still confined near and south of a slowly weakening synoptic front over northern FL, the northern Gulf shelf waters, and southeast to north-central TX. Nonetheless, a plume of mainly 60s F surface dewpoints was analyzed from much of OK north-northwestward across western/central portions of KS, NE and the Dakotas. A lee trough was drawn farther west, over eastern portions of MT/WY/CO. This trough should intensify through the day as ridging aloft shifts somewhat eastward, and southwest flow aloft spreads over more of the High Plains. As part of that process, surface cyclogenesis is expected over the northeastern WY/southeastern MT region, with the resulting low shifting eastward into northwestern SD around 06Z. ...Northern Plains... Widely scattered to scattered thunderstorms are expected to develop initially over the higher terrain of south-central/southwestern MT by midafternoon. In this area, heating of greater elevations preferentially removes MLCINH first, as large-scale lift ahead of the ejecting shortwave begins to move overhead. This activity should move northeastward into parts of central MT atop a boundary layer that is diurnally destabilizing/mixing, yet still favorably moist. Additional thunderstorms may develop by late afternoon near the surface trough, where strong surface heating and the western rim of the corridor of greatest moisture (surface dewpoints commonly in the upper 50s to mid 60s F) will remove capping at lower elevations. Convection of both origins may merge near the trough, over eastern MT. Along the way, activity should produce at least occasional large hail (mainly with any sustained supercells) and damaging gusts. Some aggregation of convection should occur, leading to forward-propagational clustering and increased potential for swath(s) of severe to potentially significant (65+ kt) gusts from late afternoon through much of the evening, as activity moves through a lingering, deep, well-mixed layer left by diurnal heating. A well-heated and deep boundary layer west of the moist plume will support MLCAPE in the 500-1500 J/kg range, with 1000-1500 J/kg DCAPE as well. This will foster high-based convection for the first few hours, with some potential for activity to cluster and become collectively outflow-dominant before reaching the grater moisture. weak low-level winds are expected, beneath 50-80 kt flow in the upper half of the buoyant profile, contributing to favorable deep shear (40-50 kt effective) for supercells, and long, relatively straight hodographs supporting splitting storms and hail potential where convection doesn't produce too much outflow too soon. Thunderstorms will move into larger nominal CAPE and greater near- surface moisture over easternmost MT into western ND, where the moist axis should be found, with MLCAPE of 2000-3000 J/kg. Though MLCINH also will be stronger in the higher-CAPE corridor than farther west, forced ascent that is driven by cold-pool processes should sustain some of the strong-severe convection well into ND this evening. Activity should peak near the moist/buoyancy axis and weaken afterword tonight, as it moves into progressively more-stable low-level profile, both with lower ambient theta-e and nocturnal diabatic cooling/stabilization near the surface. ...Central High Plains... Widely scattered to scattered thunderstorms should develop this afternoon over higher terrain from the Black Hills to the Laramie Range and southward over the Front Range, its foothills, and adjoining ridges such as the Cheyenne Ridge and Palmer Divide. This convection should move east toward the lee trough and low-level moist axis, while crossing over a hot, deeply mixed boundary layer. Isolated severe gusts are expected, and severe hail also may be a concern with relatively discrete cells. While vertical shear will be weaker than farther north, strong veering of flow with height (especially near the trough) should contribute enough deep shear (30-40 kt effective mainly north of I-70) for at least brief supercell potential. Aggregation of outflows may foster one or more eastward-surging clusters into this evening from western KS to central SD, and a relatively concentrated local severe-wind threat will exist in any such cluster. However, guidance is too inconsistent in convective evolution and longevity, and in location/number of such clusters, to assign greater unconditional probabilities within the long "marginal" area at this time. ...Southeastern AZ... Scattered thunderstorms are expected to develop this afternoon, at first over higher terrain then across deserts/valleys as outflow/ differential-heating boundaries develop. With a relatively deep layer of south-southeasterly midlevel flow, activity should move generally northwestward. Though most progs keep the flow aloft modest (15 kt or less), some mesoscale enhancement is possible east of the track of a northwestward-moving MCV -- evident in IR satellite imagery over north-central Sonora. The most intense convection will be capable of isolated severe gusts. Clouds related both to earlier/overnight convection over southern AZ, as well as to activity over MX, are south and west of this region already, portending essentially a full day of insolation over the outlook area. Residual lower-elevation surface dewpoints in the 50s to mid 60s should decrease only slightly through the diurnal heating/mixing cycle, offset to some extent by moist advection. MLCAPE in the 1000-2000 J/kg range should develop through early/mid afternoon, atop the well-mixed subcloud/boundary layer. ..Edwards/Mosier.. 08/21/2024 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0751 AM CDT Wed Aug 21 2024 Valid 211300Z - 221200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER PARTS OF EASTERN MONTANA AND WESTERN NORTH DAKOTA... ...SUMMARY... Severe hail and thunderstorm gusts are most probable over parts of eastern Montana and western North Dakota. ...Synopsis... The CONUS portion of the large-scale, mid/upper-level pattern this period will be characterized by mean troughing over the East and West Coasts, and ridging extending northward over the Great Plains States from a high over west TX. A strong cyclone -- initially centered just south of the AK Panhandle -- is expected to dig south-southeastward, with its 500-mb center moving to around 200 nm west of UIL by 12Z tomorrow. As this process reinforces the mean western trough, a series of mostly low-amplitude shortwave perturbations will eject through the foregoing southwest flow. The best-defined and potentially most important of those perturbations evident in moisture-channel imagery over portions of northern CA, northwestern NV and southeastern OR. This feature should reach southeastern ID and west-central MT around 00Z, before ejecting northeastward across the northern High Plains and losing definition tonight. Meanwhile, in the subtropical easterlies, a shortwave trough will continue to drift westward across parts of Sonora, the Gulf of California, and central/northern Baja. At the surface, 11Z analysis showed rich Gulf-origin moisture still confined near and south of a slowly weakening synoptic front over northern FL, the northern Gulf shelf waters, and southeast to north-central TX. Nonetheless, a plume of mainly 60s F surface dewpoints was analyzed from much of OK north-northwestward across western/central portions of KS, NE and the Dakotas. A lee trough was drawn farther west, over eastern portions of MT/WY/CO. This trough should intensify through the day as ridging aloft shifts somewhat eastward, and southwest flow aloft spreads over more of the High Plains. As part of that process, surface cyclogenesis is expected over the northeastern WY/southeastern MT region, with the resulting low shifting eastward into northwestern SD around 06Z. ...Northern Plains... Widely scattered to scattered thunderstorms are expected to develop initially over the higher terrain of south-central/southwestern MT by midafternoon. In this area, heating of greater elevations preferentially removes MLCINH first, as large-scale lift ahead of the ejecting shortwave begins to move overhead. This activity should move northeastward into parts of central MT atop a boundary layer that is diurnally destabilizing/mixing, yet still favorably moist. Additional thunderstorms may develop by late afternoon near the surface trough, where strong surface heating and the western rim of the corridor of greatest moisture (surface dewpoints commonly in the upper 50s to mid 60s F) will remove capping at lower elevations. Convection of both origins may merge near the trough, over eastern MT. Along the way, activity should produce at least occasional large hail (mainly with any sustained supercells) and damaging gusts. Some aggregation of convection should occur, leading to forward-propagational clustering and increased potential for swath(s) of severe to potentially significant (65+ kt) gusts from late afternoon through much of the evening, as activity moves through a lingering, deep, well-mixed layer left by diurnal heating. A well-heated and deep boundary layer west of the moist plume will support MLCAPE in the 500-1500 J/kg range, with 1000-1500 J/kg DCAPE as well. This will foster high-based convection for the first few hours, with some potential for activity to cluster and become collectively outflow-dominant before reaching the grater moisture. weak low-level winds are expected, beneath 50-80 kt flow in the upper half of the buoyant profile, contributing to favorable deep shear (40-50 kt effective) for supercells, and long, relatively straight hodographs supporting splitting storms and hail potential where convection doesn't produce too much outflow too soon. Thunderstorms will move into larger nominal CAPE and greater near- surface moisture over easternmost MT into western ND, where the moist axis should be found, with MLCAPE of 2000-3000 J/kg. Though MLCINH also will be stronger in the higher-CAPE corridor than farther west, forced ascent that is driven by cold-pool processes should sustain some of the strong-severe convection well into ND this evening. Activity should peak near the moist/buoyancy axis and weaken afterword tonight, as it moves into progressively more-stable low-level profile, both with lower ambient theta-e and nocturnal diabatic cooling/stabilization near the surface. ...Central High Plains... Widely scattered to scattered thunderstorms should develop this afternoon over higher terrain from the Black Hills to the Laramie Range and southward over the Front Range, its foothills, and adjoining ridges such as the Cheyenne Ridge and Palmer Divide. This convection should move east toward the lee trough and low-level moist axis, while crossing over a hot, deeply mixed boundary layer. Isolated severe gusts are expected, and severe hail also may be a concern with relatively discrete cells. While vertical shear will be weaker than farther north, strong veering of flow with height (especially near the trough) should contribute enough deep shear (30-40 kt effective mainly north of I-70) for at least brief supercell potential. Aggregation of outflows may foster one or more eastward-surging clusters into this evening from western KS to central SD, and a relatively concentrated local severe-wind threat will exist in any such cluster. However, guidance is too inconsistent in convective evolution and longevity, and in location/number of such clusters, to assign greater unconditional probabilities within the long "marginal" area at this time. ...Southeastern AZ... Scattered thunderstorms are expected to develop this afternoon, at first over higher terrain then across deserts/valleys as outflow/ differential-heating boundaries develop. With a relatively deep layer of south-southeasterly midlevel flow, activity should move generally northwestward. Though most progs keep the flow aloft modest (15 kt or less), some mesoscale enhancement is possible east of the track of a northwestward-moving MCV -- evident in IR satellite imagery over north-central Sonora. The most intense convection will be capable of isolated severe gusts. Clouds related both to earlier/overnight convection over southern AZ, as well as to activity over MX, are south and west of this region already, portending essentially a full day of insolation over the outlook area. Residual lower-elevation surface dewpoints in the 50s to mid 60s should decrease only slightly through the diurnal heating/mixing cycle, offset to some extent by moist advection. MLCAPE in the 1000-2000 J/kg range should develop through early/mid afternoon, atop the well-mixed subcloud/boundary layer. ..Edwards/Mosier.. 08/21/2024 Read more

709
ABPZ20 KNHC 211147
TWOEP

Tropical Weather Outlook
NWS National Hurricane Center Miami FL
500 AM PDT Wed Aug 21 2024

For the eastern North Pacific...east of 140 degrees west longitude:

Active Systems:
The National Hurricane Center is issuing advisories on recently
upgraded Hurricane Gilma, located several hundred miles
west-southwest of the southern tip of the Baja California
peninsula.

Well East-Southeast of the Hawaiian Islands (EP90/EP91):
Showers and thunderstorms continue to become better organized
in association with a well-defined area of low pressure located
well east-southeast of the Hawaiian Islands. If these trends
continue, a tropical depression or tropical storm is likely to
develop later today while it moves generally westward at 10 to 15
mph. A weaker disturbance located just to its southwest is expected
to merge with this system later today. This system is expected to
strengthen as it moves into the central Pacific basin tonight or on
Thursday and moves near the Hawaiian Islands late this weekend or
early next week.

Interests in Hawaii should closely monitor this disturbance, though
it remains too early to determine the exact location and magnitude
of potential impacts. Information on this system's development can
also be found in the Tropical Weather Outlook for the Central
Pacific basin. For marine forecasts, including gale warnings, see
High Seas Forecasts issued by the National Weather Service.
* Formation chance through 48 hours...high...90 percent.
* Formation chance through 7 days...high...90 percent.

Eastern and Central Portion of the East Pacific:
Disorganized showers and thunderstorms continue in association with
a trough of low pressure centered several hundred miles southwest of
the coast of southwestern Mexico. Environmental conditions are
forecast to become more conducive for development in a few days, and
a tropical depression is likely to form late this week or over the
weekend while the system moves west-northwestward into the central
portion of the East Pacific, well offshore of Mexico.
* Formation chance through 48 hours...low...30 percent.
* Formation chance through 7 days...high...70 percent.

&&
High Seas Forecasts issued by the National Weather Service can be
found under AWIPS header NFDHSFEPI, WMO header FZPN02 KWBC, and on
the web at ocean.weather.gov/shtml/NFDHSFEPI.php

The Tropical Weather Outlook for the Central Pacific basin can be
found under AWIPS header HFOTWOCP and WMO header ACPN50 PHFO and on
the web at hurricanes.gov

$$
Forecaster Papin/Alaka

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0355 AM CDT Wed Aug 21 2024 Valid 241200Z - 291200Z ...DISCUSSION... ...Saturday/Day 4 to Monday/Day 6... Heights within an upper-level ridge are forecast to rise across the central and northern U.S over the weekend, as an upper-level trough moves across the western U.S. Isolated severe-thunderstorm development will be possible across the Dakotas in the afternoon and evening both Saturday and Sunday. The best chance for severe storms would be on Sunday as large-scale ascent and deep-layer shear both increase across the northern Plains due to the approach of the trough. The severe threat is forecast to shift eastward into the upper Mississippi Valley on Monday, as the upper-level trough and its associated cold front advance eastward from the northern Plains into the upper Mississippi Valley. ...Tuesday/Day 7 and Wednesday/Day 8... On Tuesday and Wednesday, the upper-level trough is forecast to deamplify as it moves through the Great Lakes region. Another upper-level trough is forecast to move through the western U.S on Tuesday and Wednesday. The best chance for severe storm development would be on Wednesday afternoon along an instability axis, most likely in either eastern parts of the northern Plains or in the upper Mississippi Valley. At this range, large model spread concerning the timing of the trough and distribution of instability suggests uncertainty is substantial. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0355 AM CDT Wed Aug 21 2024 Valid 241200Z - 291200Z ...DISCUSSION... ...Saturday/Day 4 to Monday/Day 6... Heights within an upper-level ridge are forecast to rise across the central and northern U.S over the weekend, as an upper-level trough moves across the western U.S. Isolated severe-thunderstorm development will be possible across the Dakotas in the afternoon and evening both Saturday and Sunday. The best chance for severe storms would be on Sunday as large-scale ascent and deep-layer shear both increase across the northern Plains due to the approach of the trough. The severe threat is forecast to shift eastward into the upper Mississippi Valley on Monday, as the upper-level trough and its associated cold front advance eastward from the northern Plains into the upper Mississippi Valley. ...Tuesday/Day 7 and Wednesday/Day 8... On Tuesday and Wednesday, the upper-level trough is forecast to deamplify as it moves through the Great Lakes region. Another upper-level trough is forecast to move through the western U.S on Tuesday and Wednesday. The best chance for severe storm development would be on Wednesday afternoon along an instability axis, most likely in either eastern parts of the northern Plains or in the upper Mississippi Valley. At this range, large model spread concerning the timing of the trough and distribution of instability suggests uncertainty is substantial. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0355 AM CDT Wed Aug 21 2024 Valid 241200Z - 291200Z ...DISCUSSION... ...Saturday/Day 4 to Monday/Day 6... Heights within an upper-level ridge are forecast to rise across the central and northern U.S over the weekend, as an upper-level trough moves across the western U.S. Isolated severe-thunderstorm development will be possible across the Dakotas in the afternoon and evening both Saturday and Sunday. The best chance for severe storms would be on Sunday as large-scale ascent and deep-layer shear both increase across the northern Plains due to the approach of the trough. The severe threat is forecast to shift eastward into the upper Mississippi Valley on Monday, as the upper-level trough and its associated cold front advance eastward from the northern Plains into the upper Mississippi Valley. ...Tuesday/Day 7 and Wednesday/Day 8... On Tuesday and Wednesday, the upper-level trough is forecast to deamplify as it moves through the Great Lakes region. Another upper-level trough is forecast to move through the western U.S on Tuesday and Wednesday. The best chance for severe storm development would be on Wednesday afternoon along an instability axis, most likely in either eastern parts of the northern Plains or in the upper Mississippi Valley. At this range, large model spread concerning the timing of the trough and distribution of instability suggests uncertainty is substantial. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0355 AM CDT Wed Aug 21 2024 Valid 241200Z - 291200Z ...DISCUSSION... ...Saturday/Day 4 to Monday/Day 6... Heights within an upper-level ridge are forecast to rise across the central and northern U.S over the weekend, as an upper-level trough moves across the western U.S. Isolated severe-thunderstorm development will be possible across the Dakotas in the afternoon and evening both Saturday and Sunday. The best chance for severe storms would be on Sunday as large-scale ascent and deep-layer shear both increase across the northern Plains due to the approach of the trough. The severe threat is forecast to shift eastward into the upper Mississippi Valley on Monday, as the upper-level trough and its associated cold front advance eastward from the northern Plains into the upper Mississippi Valley. ...Tuesday/Day 7 and Wednesday/Day 8... On Tuesday and Wednesday, the upper-level trough is forecast to deamplify as it moves through the Great Lakes region. Another upper-level trough is forecast to move through the western U.S on Tuesday and Wednesday. The best chance for severe storm development would be on Wednesday afternoon along an instability axis, most likely in either eastern parts of the northern Plains or in the upper Mississippi Valley. At this range, large model spread concerning the timing of the trough and distribution of instability suggests uncertainty is substantial. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0355 AM CDT Wed Aug 21 2024 Valid 241200Z - 291200Z ...DISCUSSION... ...Saturday/Day 4 to Monday/Day 6... Heights within an upper-level ridge are forecast to rise across the central and northern U.S over the weekend, as an upper-level trough moves across the western U.S. Isolated severe-thunderstorm development will be possible across the Dakotas in the afternoon and evening both Saturday and Sunday. The best chance for severe storms would be on Sunday as large-scale ascent and deep-layer shear both increase across the northern Plains due to the approach of the trough. The severe threat is forecast to shift eastward into the upper Mississippi Valley on Monday, as the upper-level trough and its associated cold front advance eastward from the northern Plains into the upper Mississippi Valley. ...Tuesday/Day 7 and Wednesday/Day 8... On Tuesday and Wednesday, the upper-level trough is forecast to deamplify as it moves through the Great Lakes region. Another upper-level trough is forecast to move through the western U.S on Tuesday and Wednesday. The best chance for severe storm development would be on Wednesday afternoon along an instability axis, most likely in either eastern parts of the northern Plains or in the upper Mississippi Valley. At this range, large model spread concerning the timing of the trough and distribution of instability suggests uncertainty is substantial. Read more

5-Day Uncertainty Track last updated Wed, 21 Aug 2024 08:51:07 GMT


Wind Speed Probabilities last updated Wed, 21 Aug 2024 09:22:53 GMT

Issued at 200 AM PDT Wed Aug 21 2024 000 WTPZ42 KNHC 210849 TCDEP2 Hurricane Gilma Discussion Number 12 NWS National Hurricane Center Miami FL EP072024 200 AM PDT Wed Aug 21 2024 Satellite images showed Gilma becoming better organized through the night until about 0700 UTC, with the low-level center embedded underneath the deep convection. A 21/0216 SSMIS pass was quite helpful showing a more impressive mid-level structure, with the low-level center likely located about 20 miles to the northwest of the mid-level center. The latest images since 0700 UTC show a dry slot in between the central convective mass and a curved band to the northwest of the center. GOES-West CIRA Proxy-Vis imagery has been hinting that the low-level center may be near the NW edge of the central convective area rather than under the middle of it. The latest subjective intensity estimates were T-4.0/65 kt from both TAFB and SAB, and the latest objective intensity estimates from UW-CIMSS range from 61-68 kt. Based on these subjective and objective intensity estimates, the initial intensity is bumped up to 65 kt, making Gilma the second hurricane of the 2024 East Pacific hurricane season. Gilma has been moving due west over the past 12 h at 270/9 kt. A mid- to upper-level ridge situated to the north of the cyclone should be the primary steering mechanism through the forecast period, taking Gilma on a westward to west-northwestward course. A broad upper-level trough is forecast to move in well north of Gilma Thursday into Friday, which should act to slow Gilma's forward speed a bit. The latest global models indicate that this trough won't have much of an influence on causing Gilma to gain latitude. As a result, the track guidance has continued to shift well to the south, showing a mostly westward track through the forecast period. The latest NHC forecast has been shifted south of the previous official forecast, but still lies closer to the previous official forecast than the latest model consensus. If this trend continues, then subsequent NHC forecasts will need to be adjusted southward. Gilma has been reorganizing structurally as it has gradually to steadily strengthened over the past 24 h. Upper-level winds are expected to become more favorable over the next day or so. Gilma should remain over relatively warm SSTs and within a moist enough airmass for the next 24 to 48 h to allow for additional steady intensification, and the forecast peak intensity remains 90 kt. By the weekend, Gilma should encounter gradually cooling sea surface temperatures and drier mid-level air, causing the cyclone to gradually weaken. Only minor changes were made to the official intensity forecast. The intensity forecast is slightly above the model consensus during the short term, and near the consensus during the latter portion of the forecast period. FORECAST POSITIONS AND MAX WINDS INIT 21/0900Z 16.0N 122.3W 65 KT 75 MPH 12H 21/1800Z 16.1N 123.3W 70 KT 80 MPH 24H 22/0600Z 16.5N 124.4W 80 KT 90 MPH 36H 22/1800Z 16.9N 125.6W 90 KT 105 MPH 48H 23/0600Z 17.2N 126.7W 90 KT 105 MPH 60H 23/1800Z 17.5N 128.1W 90 KT 105 MPH 72H 24/0600Z 17.7N 129.6W 85 KT 100 MPH 96H 25/0600Z 18.3N 132.8W 70 KT 80 MPH 120H 26/0600Z 19.1N 136.7W 60 KT 70 MPH $$ Forecaster Hagen/Pasch

Issued at 0900 UTC WED AUG 21 2024 000 FOPZ12 KNHC 210847 PWSEP2 HURRICANE GILMA WIND SPEED PROBABILITIES NUMBER 12 NWS NATIONAL HURRICANE CENTER MIAMI FL EP072024 0900 UTC WED AUG 21 2024 AT 0900Z THE CENTER OF HURRICANE GILMA WAS LOCATED NEAR LATITUDE 16.0 NORTH...LONGITUDE 122.3 WEST WITH MAXIMUM SUSTAINED WINDS NEAR 65 KTS...75 MPH...120 KM/H. Z INDICATES COORDINATED UNIVERSAL TIME (GREENWICH) PACIFIC DAYLIGHT TIME (PDT)...SUBTRACT 7 HOURS FROM Z TIME HAWAIIAN STANDARD TIME (HST)...SUBTRACT 10 HOURS FROM Z TIME WIND SPEED PROBABILITY TABLE FOR SPECIFIC LOCATIONS CHANCES OF SUSTAINED (1-MINUTE AVERAGE) WIND SPEEDS OF AT LEAST ...34 KT (39 MPH... 63 KM/H)... ...50 KT (58 MPH... 93 KM/H)... ...64 KT (74 MPH...119 KM/H)... FOR LOCATIONS AND TIME PERIODS DURING THE NEXT 5 DAYS PROBABILITIES FOR LOCATIONS ARE GIVEN AS OP(CP) WHERE OP IS THE PROBABILITY OF THE EVENT BEGINNING DURING AN INDIVIDUAL TIME PERIOD (ONSET PROBABILITY) (CP) IS THE PROBABILITY OF THE EVENT OCCURRING BETWEEN 06Z WED AND THE FORECAST HOUR (CUMULATIVE PROBABILITY) PROBABILITIES ARE GIVEN IN PERCENT X INDICATES PROBABILITIES LESS THAN 1 PERCENT PROBABILITIES FOR 34 KT AND 50 KT ARE SHOWN AT A GIVEN LOCATION WHEN THE 5-DAY CUMULATIVE PROBABILITY IS AT LEAST 3 PERCENT. PROBABILITIES FOR 34...50...64 KT SHOWN WHEN THE 5-DAY 64-KT CUMULATIVE PROBABILITY IS AT LEAST 1 PERCENT. - - - - WIND SPEED PROBABILITIES FOR SELECTED LOCATIONS - - - - FROM FROM FROM FROM FROM FROM FROM TIME 06Z WED 18Z WED 06Z THU 18Z THU 06Z FRI 06Z SAT 06Z SUN PERIODS TO TO TO TO TO TO TO 18Z WED 06Z THU 18Z THU 06Z FRI 06Z SAT 06Z SUN 06Z MON FORECAST HOUR (12) (24) (36) (48) (72) (96) (120) - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - LOCATION KT 15N 120W 34 1 2( 3) 1( 4) X( 4) X( 4) X( 4) X( 4) 15N 125W 34 17 42(59) 7(66) 1(67) 1(68) X(68) X(68) 15N 125W 50 X 2( 2) 3( 5) X( 5) 1( 6) X( 6) X( 6) 15N 125W 64 X X( X) 1( 1) X( 1) X( 1) X( 1) X( 1) 20N 125W 34 1 2( 3) 7(10) 7(17) 4(21) 1(22) X(22) 15N 130W 34 X X( X) 3( 3) 3( 6) 14(20) 4(24) 1(25) 15N 130W 50 X X( X) X( X) X( X) 3( 3) X( 3) X( 3) 15N 130W 64 X X( X) X( X) X( X) 1( 1) X( 1) X( 1) 20N 130W 34 X X( X) 1( 1) 5( 6) 32(38) 11(49) 1(50) 20N 130W 50 X X( X) X( X) X( X) 8( 8) 5(13) X(13) 20N 130W 64 X X( X) X( X) X( X) 2( 2) 3( 5) X( 5) 15N 135W 34 X X( X) X( X) X( X) X( X) 5( 5) 4( 9) 20N 135W 34 X X( X) X( X) X( X) 1( 1) 20(21) 26(47) 20N 135W 50 X X( X) X( X) X( X) X( X) 4( 4) 11(15) 20N 135W 64 X X( X) X( X) X( X) X( X) 1( 1) 3( 4) 20N 140W 34 X X( X) X( X) X( X) X( X) 1( 1) 9(10) $$ FORECASTER HAGEN/PASCH

Issued at 200 AM PDT Wed Aug 21 2024 000 WTPZ32 KNHC 210847 TCPEP2 BULLETIN Hurricane Gilma Advisory Number 12 NWS National Hurricane Center Miami FL EP072024 200 AM PDT Wed Aug 21 2024 ...GILMA BECOMES THE SECOND HURRICANE OF THE 2024 EAST PACIFIC HURRICANE SEASON... SUMMARY OF 200 AM PDT...0900 UTC...INFORMATION ---------------------------------------------- LOCATION...16.0N 122.3W ABOUT 935 MI...1505 KM WSW OF THE SOUTHERN TIP OF BAJA CALIFORNIA MAXIMUM SUSTAINED WINDS...75 MPH...120 KM/H PRESENT MOVEMENT...W OR 270 DEGREES AT 10 MPH...17 KM/H MINIMUM CENTRAL PRESSURE...990 MB...29.24 INCHES WATCHES AND WARNINGS -------------------- There are no coastal watches or warnings in effect. DISCUSSION AND OUTLOOK ---------------------- At 200 AM PDT (0900 UTC), the center of Hurricane Gilma was located near latitude 16.0 North, longitude 122.3 West. Gilma is moving toward the west near 10 mph (17 km/h). A slightly slower westward to west-northwestward motion is expected during the next few days. Maximum sustained winds are near 75 mph (120 km/h) with higher gusts. Additional strengthening is forecast during the next couple of days. Hurricane-force winds extend outward up to 25 miles (35 km) from the center and tropical-storm-force winds extend outward up to 140 miles (220 km). The estimated minimum central pressure is 990 mb (29.24 inches). HAZARDS AFFECTING LAND ---------------------- None NEXT ADVISORY ------------- Next complete advisory at 800 AM PDT. $$ Forecaster Hagen/Pasch

...GILMA BECOMES THE SECOND HURRICANE OF THE 2024 EAST PACIFIC HURRICANE SEASON... As of 2:00 AM PDT Wed Aug 21 the center of Gilma was located near 16.0, -122.3 with movement W at 10 mph. The minimum central pressure was 990 mb with maximum sustained winds of about 75 mph.

Issued at 0900 UTC WED AUG 21 2024 000 WTPZ22 KNHC 210846 TCMEP2 HURRICANE GILMA FORECAST/ADVISORY NUMBER 12 NWS NATIONAL HURRICANE CENTER MIAMI FL EP072024 0900 UTC WED AUG 21 2024 HURRICANE CENTER LOCATED NEAR 16.0N 122.3W AT 21/0900Z POSITION ACCURATE WITHIN 30 NM PRESENT MOVEMENT TOWARD THE WEST OR 270 DEGREES AT 9 KT ESTIMATED MINIMUM CENTRAL PRESSURE 990 MB MAX SUSTAINED WINDS 65 KT WITH GUSTS TO 80 KT. 64 KT....... 20NE 20SE 0SW 0NW. 50 KT....... 30NE 30SE 20SW 0NW. 34 KT....... 60NE 100SE 120SW 50NW. 12 FT SEAS..180NE 210SE 150SW 90NW. WINDS AND SEAS VARY GREATLY IN EACH QUADRANT. RADII IN NAUTICAL MILES ARE THE LARGEST RADII EXPECTED ANYWHERE IN THAT QUADRANT. REPEAT...CENTER LOCATED NEAR 16.0N 122.3W AT 21/0900Z AT 21/0600Z CENTER WAS LOCATED NEAR 15.9N 122.0W FORECAST VALID 21/1800Z 16.1N 123.3W MAX WIND 70 KT...GUSTS 85 KT. 64 KT... 20NE 20SE 0SW 0NW. 50 KT... 30NE 30SE 20SW 0NW. 34 KT... 60NE 100SE 110SW 60NW. FORECAST VALID 22/0600Z 16.5N 124.4W MAX WIND 80 KT...GUSTS 100 KT. 64 KT... 20NE 20SE 15SW 15NW. 50 KT... 30NE 30SE 30SW 30NW. 34 KT... 70NE 90SE 90SW 60NW. FORECAST VALID 22/1800Z 16.9N 125.6W MAX WIND 90 KT...GUSTS 110 KT. 64 KT... 20NE 20SE 20SW 20NW. 50 KT... 40NE 40SE 30SW 40NW. 34 KT... 80NE 80SE 80SW 70NW. FORECAST VALID 23/0600Z 17.2N 126.7W MAX WIND 90 KT...GUSTS 110 KT. 64 KT... 20NE 20SE 20SW 20NW. 50 KT... 40NE 40SE 40SW 40NW. 34 KT... 90NE 80SE 80SW 80NW. FORECAST VALID 23/1800Z 17.5N 128.1W MAX WIND 90 KT...GUSTS 110 KT. 50 KT... 40NE 40SE 40SW 40NW. 34 KT... 90NE 70SE 70SW 90NW. FORECAST VALID 24/0600Z 17.7N 129.6W MAX WIND 85 KT...GUSTS 105 KT. 50 KT... 40NE 40SE 40SW 40NW. 34 KT... 90NE 70SE 70SW 90NW. EXTENDED OUTLOOK. NOTE...ERRORS FOR TRACK HAVE AVERAGED NEAR 100 NM ON DAY 4 AND 125 NM ON DAY 5...AND FOR INTENSITY NEAR 15 KT EACH DAY OUTLOOK VALID 25/0600Z 18.3N 132.8W MAX WIND 70 KT...GUSTS 85 KT. 50 KT... 40NE 40SE 30SW 40NW. 34 KT...100NE 70SE 70SW 90NW. OUTLOOK VALID 26/0600Z 19.1N 136.7W MAX WIND 60 KT...GUSTS 75 KT. 50 KT... 40NE 40SE 30SW 40NW. 34 KT...100NE 70SE 60SW 90NW. REQUEST FOR 3 HOURLY SHIP REPORTS WITHIN 300 MILES OF 16.0N 122.3W NEXT ADVISORY AT 21/1500Z $$ FORECASTER HAGEN/PASCH

SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0225 AM CDT Wed Aug 21 2024 Valid 231200Z - 241200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE CENTRAL AND NORTHERN PLAINS...AND IN PARTS OF THE INTERMOUNTAIN WEST AND CENTRAL ROCKIES... ...SUMMARY... Marginally severe storms with hail and isolated severe gusts will be possible on Friday across parts of the central and northern Plains, and in parts of the Intermountain West and central Rockies. ...Central and Northern Plains... An upper-level ridge will remain over eastern parts of the central and northern Plains on Friday. A north-to-south axis of moisture and instability is forecast across Kansas, Nebraska, South Dakota and eastern Montana, where isolated thunderstorm development will be possible during the afternoon and evening. Forecast soundings near the area of strongest instability late Friday afternoon in northern Kansas and southwest Nebraska suggest MLCAPE will peak in the 2000 to 3000 J/kg range and 0-6 km shear will be from 30 to 40 knots. This, combined with steep low to mid-level lapse rates should support an isolated severe threat. However, large-scale ascent is forecast to be absent across much of the region. For this reason, updrafts may struggle to intensify due to subsidence in the wake of the ridge, keeping any severe threat marginal. ...Eastern Utah/Western Colorado/Far Southwest Wyoming... An upper-level low is forecast to approach the coast of Oregon on Friday as southwest mid-level flow remains over much of the Intermountain West. A shortwave trough is forecast to move through the western U.S., which will likely aid the development of scattered thunderstorms in the afternoon from eastern Utah eastward into the central Rockies. The models suggest that weak instability, moderate deep-layer shear and steep low to mid-level lapse rates will be in place, which would be sufficient for marginal severe threat. Hail and isolated severe gusts will be possible mainly during the mid to late afternoon. ..Broyles.. 08/21/2024 Read more