Aggregator

Issued at 1500 UTC SAT SEP 14 2024 000 FOPZ14 KNHC 141438 PWSEP4 TROPICAL STORM ILEANA WIND SPEED PROBABILITIES NUMBER 9 NWS NATIONAL HURRICANE CENTER MIAMI FL EP092024 1500 UTC SAT SEP 14 2024 AT 1500Z THE CENTER OF TROPICAL STORM ILEANA WAS LOCATED NEAR LATITUDE 24.9 NORTH...LONGITUDE 108.9 WEST WITH MAXIMUM SUSTAINED WINDS NEAR 35 KTS...40 MPH...65 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 12Z SAT 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 12Z SAT 00Z SUN 12Z SUN 00Z MON 12Z MON 12Z TUE 12Z WED PERIODS TO TO TO TO TO TO TO 00Z SUN 12Z SUN 00Z MON 12Z MON 12Z TUE 12Z WED 12Z THU FORECAST HOUR (12) (24) (36) (48) (72) (96) (120) - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - LOCATION KT GUAYMAS 34 X 1( 1) 1( 2) 1( 3) X( 3) X( 3) X( 3) HUATABAMPO 34 X 3( 3) 1( 4) X( 4) X( 4) X( 4) X( 4) LOS MOCHIS 34 9 2(11) 1(12) X(12) X(12) X(12) X(12) $$ FORECASTER BEVEN

Issued at 800 AM MST Sat Sep 14 2024 000 WTPZ44 KNHC 141438 TCDEP4 Tropical Storm Ileana Discussion Number 9 NWS National Hurricane Center Miami FL EP092024 800 AM MST Sat Sep 14 2024 Satellite imagery shows that Ileana is being affected by increasing southwesterly shear. A large burst of convection that occurred in the early morning hours has moved northeast of the exposed low-level center, while new convection is forming to the north and southeast of the center. The initial intensity is held at 35 kt based on various satellite intensity estimates and earlier surface data from Topolobampo, Mexico. The initial motion is just east of due north or 010/6 kt. This general motion should continue for the next 6 hours or so, bringing the center near or over the coast of Mexico near Topolobampo and Los Mochis today. After that, Ileana should begin a slow motion toward the northwest over the Gulf of California roughly parallel to the coast of Mexico, with this motion continuing until the system dissipates. The new track forecast is nudged to the north and east of the previous track and lies near the various consensus models. Ileana is expected to weaken below tropical-storm strength later today due to a combination of shear and land interaction. However, before that happens, the cyclone should bring tropical storm conditions to portions of the northern coast of Sinaloa and southern coast of Sonora through this afternoon. The system is expected to degenerate to a remnant low between 12-24 h, with the remnant low dissipating over the central Gulf of California on Monday. Key Messages: 1. Tropical Storm Ileana will bring heavy rainfall to portions of coastal Sinaloa, Mexico through this weekend. This heavy rainfall will bring a risk of flash flooding and mudslides to portions of the area. 2. Tropical storm conditions are expected within the warning area of northern Sinaloa and southern Sonora through this afternoon. FORECAST POSITIONS AND MAX WINDS INIT 14/1500Z 24.9N 108.9W 35 KT 40 MPH 12H 15/0000Z 25.6N 109.2W 30 KT 35 MPH...NEAR COAST 24H 15/1200Z 26.3N 109.8W 25 KT 30 MPH...POST-TROP/REMNT LOW 36H 16/0000Z 26.9N 110.3W 25 KT 30 MPH...POST-TROP/REMNT LOW 48H 16/1200Z 27.7N 111.0W 20 KT 25 MPH...POST-TROP/REMNT LOW 60H 17/0000Z...DISSIPATED $$ Forecaster Beven

Issued at 1500 UTC SAT SEP 14 2024 000 WTPZ24 KNHC 141438 TCMEP4 TROPICAL STORM ILEANA FORECAST/ADVISORY NUMBER 9 NWS NATIONAL HURRICANE CENTER MIAMI FL EP092024 1500 UTC SAT SEP 14 2024 TROPICAL STORM CENTER LOCATED NEAR 24.9N 108.9W AT 14/1500Z POSITION ACCURATE WITHIN 30 NM PRESENT MOVEMENT TOWARD THE NORTH OR 10 DEGREES AT 6 KT ESTIMATED MINIMUM CENTRAL PRESSURE 1002 MB MAX SUSTAINED WINDS 35 KT WITH GUSTS TO 45 KT. 34 KT....... 50NE 50SE 0SW 0NW. 12 FT SEAS.. 30NE 30SE 0SW 0NW. 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 24.9N 108.9W AT 14/1500Z AT 14/1200Z CENTER WAS LOCATED NEAR 24.7N 109.1W FORECAST VALID 15/0000Z 25.6N 109.2W...NEAR COAST MAX WIND 30 KT...GUSTS 40 KT. FORECAST VALID 15/1200Z 26.3N 109.8W...POST-TROP/REMNT LOW MAX WIND 25 KT...GUSTS 35 KT. FORECAST VALID 16/0000Z 26.9N 110.3W...POST-TROP/REMNT LOW MAX WIND 25 KT...GUSTS 35 KT. FORECAST VALID 16/1200Z 27.7N 111.0W...POST-TROP/REMNT LOW MAX WIND 20 KT...GUSTS 30 KT. FORECAST VALID 17/0000Z...DISSIPATED REQUEST FOR 3 HOURLY SHIP REPORTS WITHIN 300 MILES OF 24.9N 108.9W INTERMEDIATE PUBLIC ADVISORY...WTNT34 KNHC/MIATCPEP4...AT 14/1800Z NEXT ADVISORY AT 14/2100Z $$ FORECASTER BEVEN

Issued at 800 AM MST Sat Sep 14 2024 000 WTPZ34 KNHC 141438 TCPEP4 BULLETIN Tropical Storm Ileana Advisory Number 9 NWS National Hurricane Center Miami FL EP092024 800 AM MST Sat Sep 14 2024 ...ILEANA MOVES CLOSER TO THE COAST OF MAINLAND MEXICO... ...TROPICAL STORM CONDITIONS AND HEAVY RAINS SPREADING ONSHORE... SUMMARY OF 800 AM MST...1500 UTC...INFORMATION ---------------------------------------------- LOCATION...24.9N 108.9W ABOUT 60 MI...100 KM S OF LOS MOCHIS MEXICO ABOUT 100 MI...160 KM ENE OF LA PAZ MEXICO MAXIMUM SUSTAINED WINDS...40 MPH...65 KM/H PRESENT MOVEMENT...N OR 10 DEGREES AT 7 MPH...11 KM/H MINIMUM CENTRAL PRESSURE...1002 MB...29.59 INCHES WATCHES AND WARNINGS -------------------- CHANGES WITH THIS ADVISORY: None. SUMMARY OF WATCHES AND WARNINGS IN EFFECT: A Tropical Storm Warning is in effect for... * Altata to Huatabampito Mexico A Tropical Storm Warning means that tropical storm conditions are expected somewhere within the warning area, in this case within 12 hours. Interests elsewhere in the Mexican states of Baja California Sur, Sinaloa, and Sonora should closely monitor the progress of Ileana. For storm information specific to your area, please monitor products issued by your national meteorological service. DISCUSSION AND OUTLOOK ---------------------- At 800 AM MST (1500 UTC), the center of Tropical Storm Ileana was located near latitude 24.9 North, longitude 108.9 West. Ileana is moving toward the north near 7 mph (11 km/h), and this general motion is expected to continue today. A slower motion toward the north-northwest and northwest is expected tonight and on Sunday. On the forecast track, the center of Ileana will move near or over the coasts of northern Sinaloa and southern Sonora later today, and then move over the Gulf of California roughly parallel to the coast on Sunday. Maximum sustained winds are near 40 mph (65 km/h) with higher gusts. Weakening is forecast to begin later this afternoon or evening, and Ileana is likely to degenerate into a remnant low tonight. The remnant low is expected to dissipate by Monday. Tropical-storm-force winds extend outward up to 60 miles (95 km) from the center. The estimated minimum central pressure is 1002 mb (29.59 inches). HAZARDS AFFECTING LAND ---------------------- Key messages for Ileana can be found in the Tropical Cyclone Discussion under AWIPS header MIATCDEP4 and WMO header WTPZ44 KNHC. RAINFALL: Tropical Storm Ileana is expected to bring additional rainfall amounts of 3 to 6 inches, with localized higher amounts up to 10 inches, across northwest coastal Sinaloa through this weekend. For a complete depiction of forecast rainfall associated with Tropical Storm Ileana, please see the National Weather Service Storm Total Rainfall Graphic, available at hurricanes.gov/graphics_ep4.shtml?rainqpf WIND: Tropical storm conditions are expected across portions of the warning area in northern Sinaloa and southern Sonora through this afternoon. SURF: Swells generated by Ileana will affect portions of the Gulf of California coasts of Sinaloa, southern Sonora, and southern Baja California Sur during the next day or so. These swells could cause life-threatening surf and rip current conditions. Please consult products from your local weather office. NEXT ADVISORY ------------- Next intermediate advisory at 1100 AM MST. Next complete advisory at 200 PM MST. $$ Forecaster Beven

...ILEANA MOVES CLOSER TO THE COAST OF MAINLAND MEXICO... ...TROPICAL STORM CONDITIONS AND HEAVY RAINS SPREADING ONSHORE... As of 8:00 AM MST Sat Sep 14 the center of Ileana was located near 24.9, -108.9 with movement N at 7 mph. The minimum central pressure was 1002 mb with maximum sustained winds of about 40 mph.

000
ABPZ20 KNHC 141259
TWOEP

Tropical Weather Outlook
NWS National Hurricane Center Miami FL
500 AM PDT Sat Sep 14 2024

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

Active Systems:
The National Hurricane Center is issuing advisories on Tropical
Storm Ileana, located over the southern Gulf of California.

Tropical cyclone formation is not expected during the next 7 days.

$$
Forecaster Beven

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0742 AM CDT Sat Sep 14 2024 Valid 141300Z - 151200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS OVER PARTS OF THE NORTH-CENTRAL PLAINS... ...SUMMARY... Thunderstorms capable of isolated severe gusts and hail will be possible over parts of the north-central Plains. ...Synopsis... Blockiness in the eastern CONUS will continue to dominate the large-scale, mid/upper-level pattern through the period. An anticyclone will drift eastward to southeastward over the Great Lakes, poleward of a broad belt of low heights and several embedded vorticity maxima extending from the lower Mississippi Valley to offshore from the Carolinas. One of those perturbations will be the decaying remnants of a merger of a midlatitude mid/upper low with the remnants of Francine. This feature is forecast to drift erratically eastward to southeastward over the Mid-South, contributing to convective potential over a broad area of the Southeast, but with wind fields and lift too weak to support organized severe potential. Farther west, synoptic-scale height rises are forecast across most of the central/northern Plains, as a strong trough digs south- southeastward near the BC Coast and forms a 500-mb low near UIL at the end of the period. By then, associated cyclonic flow should cover a large part of the CONUS west of the Rockies, as well as for several hundred miles off the West Coast. The 11Z surface analysis showed a low over northern MS (associated with the remnants of Francine) with an occluded front arching across AL to a triple point near MGM, a warm front across southern GA, and a cold front across the western FL Panhandle. These boundaries should become more diffuse with time today as the deep-layer cyclone above the low continues its gradual degradation. Meanwhile, a quasistationary front from east-central ND across central SD to southwestern NE should weaken through the day, but with a remnant trough/convergence zone lingering near the present position. A weak surface low should form farther west today, in northeastern WY east of GCC, then migrate eastward into western SD toward RAP tonight. ...North-central Plains... Isolated to scattered thunderstorms are expected to develop this afternoon, in a narrow corridor of relatively maximized low-level convergence (corresponding to the weak front/trough) and favorably strong surface heating east through southeast of the low. Isolated severe gusts and hail will be possible as convection proceeds across SD and perhaps into southern ND this evening, before encountering progressively more-stable low-level conditions with a decreasing severe threat. A weak perturbation apparent in moisture-channel imagery over east-central WY should move northeastward across the western NE Panhandle to southwestern/south-central SD by mid/late afternoon, and may contribute subtle large-scale ascent to the environment. Still, with broader, ambient height rises superimposed on that, considerable mesoscale timing/location uncertainty remains on the most probable initiation zone within the southern part of the outlook area. The later initiation occurs, the farther north the unconditional severe-threat area will be. Activity should move north-northeastward into a corridor of favorable moisture and buoyancy, with peak MLCAPE in the 500-1500 J/kg range, atop a well-mixed subcloud layer. Greater lift and more backing of low level flow will be present over the SD part of the outlook, spreading northward into southern ND with time this evening, and supporting conditional potential for upscale growth of activity initiating in a hotter boundary layer near the Badlands. Stronger capping and weaker convergence over western NE cast some doubt as to formation and convective coverage in the Sandhills, though the environment will be favorable for marginal severe there as well. Modest low/middle-level winds nonetheless will veer strongly with height, leading to 25-35-kt effective-shear magnitudes in support of some organization. ..Edwards/Mosier.. 09/14/2024 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0742 AM CDT Sat Sep 14 2024 Valid 141300Z - 151200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS OVER PARTS OF THE NORTH-CENTRAL PLAINS... ...SUMMARY... Thunderstorms capable of isolated severe gusts and hail will be possible over parts of the north-central Plains. ...Synopsis... Blockiness in the eastern CONUS will continue to dominate the large-scale, mid/upper-level pattern through the period. An anticyclone will drift eastward to southeastward over the Great Lakes, poleward of a broad belt of low heights and several embedded vorticity maxima extending from the lower Mississippi Valley to offshore from the Carolinas. One of those perturbations will be the decaying remnants of a merger of a midlatitude mid/upper low with the remnants of Francine. This feature is forecast to drift erratically eastward to southeastward over the Mid-South, contributing to convective potential over a broad area of the Southeast, but with wind fields and lift too weak to support organized severe potential. Farther west, synoptic-scale height rises are forecast across most of the central/northern Plains, as a strong trough digs south- southeastward near the BC Coast and forms a 500-mb low near UIL at the end of the period. By then, associated cyclonic flow should cover a large part of the CONUS west of the Rockies, as well as for several hundred miles off the West Coast. The 11Z surface analysis showed a low over northern MS (associated with the remnants of Francine) with an occluded front arching across AL to a triple point near MGM, a warm front across southern GA, and a cold front across the western FL Panhandle. These boundaries should become more diffuse with time today as the deep-layer cyclone above the low continues its gradual degradation. Meanwhile, a quasistationary front from east-central ND across central SD to southwestern NE should weaken through the day, but with a remnant trough/convergence zone lingering near the present position. A weak surface low should form farther west today, in northeastern WY east of GCC, then migrate eastward into western SD toward RAP tonight. ...North-central Plains... Isolated to scattered thunderstorms are expected to develop this afternoon, in a narrow corridor of relatively maximized low-level convergence (corresponding to the weak front/trough) and favorably strong surface heating east through southeast of the low. Isolated severe gusts and hail will be possible as convection proceeds across SD and perhaps into southern ND this evening, before encountering progressively more-stable low-level conditions with a decreasing severe threat. A weak perturbation apparent in moisture-channel imagery over east-central WY should move northeastward across the western NE Panhandle to southwestern/south-central SD by mid/late afternoon, and may contribute subtle large-scale ascent to the environment. Still, with broader, ambient height rises superimposed on that, considerable mesoscale timing/location uncertainty remains on the most probable initiation zone within the southern part of the outlook area. The later initiation occurs, the farther north the unconditional severe-threat area will be. Activity should move north-northeastward into a corridor of favorable moisture and buoyancy, with peak MLCAPE in the 500-1500 J/kg range, atop a well-mixed subcloud layer. Greater lift and more backing of low level flow will be present over the SD part of the outlook, spreading northward into southern ND with time this evening, and supporting conditional potential for upscale growth of activity initiating in a hotter boundary layer near the Badlands. Stronger capping and weaker convergence over western NE cast some doubt as to formation and convective coverage in the Sandhills, though the environment will be favorable for marginal severe there as well. Modest low/middle-level winds nonetheless will veer strongly with height, leading to 25-35-kt effective-shear magnitudes in support of some organization. ..Edwards/Mosier.. 09/14/2024 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0742 AM CDT Sat Sep 14 2024 Valid 141300Z - 151200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS OVER PARTS OF THE NORTH-CENTRAL PLAINS... ...SUMMARY... Thunderstorms capable of isolated severe gusts and hail will be possible over parts of the north-central Plains. ...Synopsis... Blockiness in the eastern CONUS will continue to dominate the large-scale, mid/upper-level pattern through the period. An anticyclone will drift eastward to southeastward over the Great Lakes, poleward of a broad belt of low heights and several embedded vorticity maxima extending from the lower Mississippi Valley to offshore from the Carolinas. One of those perturbations will be the decaying remnants of a merger of a midlatitude mid/upper low with the remnants of Francine. This feature is forecast to drift erratically eastward to southeastward over the Mid-South, contributing to convective potential over a broad area of the Southeast, but with wind fields and lift too weak to support organized severe potential. Farther west, synoptic-scale height rises are forecast across most of the central/northern Plains, as a strong trough digs south- southeastward near the BC Coast and forms a 500-mb low near UIL at the end of the period. By then, associated cyclonic flow should cover a large part of the CONUS west of the Rockies, as well as for several hundred miles off the West Coast. The 11Z surface analysis showed a low over northern MS (associated with the remnants of Francine) with an occluded front arching across AL to a triple point near MGM, a warm front across southern GA, and a cold front across the western FL Panhandle. These boundaries should become more diffuse with time today as the deep-layer cyclone above the low continues its gradual degradation. Meanwhile, a quasistationary front from east-central ND across central SD to southwestern NE should weaken through the day, but with a remnant trough/convergence zone lingering near the present position. A weak surface low should form farther west today, in northeastern WY east of GCC, then migrate eastward into western SD toward RAP tonight. ...North-central Plains... Isolated to scattered thunderstorms are expected to develop this afternoon, in a narrow corridor of relatively maximized low-level convergence (corresponding to the weak front/trough) and favorably strong surface heating east through southeast of the low. Isolated severe gusts and hail will be possible as convection proceeds across SD and perhaps into southern ND this evening, before encountering progressively more-stable low-level conditions with a decreasing severe threat. A weak perturbation apparent in moisture-channel imagery over east-central WY should move northeastward across the western NE Panhandle to southwestern/south-central SD by mid/late afternoon, and may contribute subtle large-scale ascent to the environment. Still, with broader, ambient height rises superimposed on that, considerable mesoscale timing/location uncertainty remains on the most probable initiation zone within the southern part of the outlook area. The later initiation occurs, the farther north the unconditional severe-threat area will be. Activity should move north-northeastward into a corridor of favorable moisture and buoyancy, with peak MLCAPE in the 500-1500 J/kg range, atop a well-mixed subcloud layer. Greater lift and more backing of low level flow will be present over the SD part of the outlook, spreading northward into southern ND with time this evening, and supporting conditional potential for upscale growth of activity initiating in a hotter boundary layer near the Badlands. Stronger capping and weaker convergence over western NE cast some doubt as to formation and convective coverage in the Sandhills, though the environment will be favorable for marginal severe there as well. Modest low/middle-level winds nonetheless will veer strongly with height, leading to 25-35-kt effective-shear magnitudes in support of some organization. ..Edwards/Mosier.. 09/14/2024 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0742 AM CDT Sat Sep 14 2024 Valid 141300Z - 151200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS OVER PARTS OF THE NORTH-CENTRAL PLAINS... ...SUMMARY... Thunderstorms capable of isolated severe gusts and hail will be possible over parts of the north-central Plains. ...Synopsis... Blockiness in the eastern CONUS will continue to dominate the large-scale, mid/upper-level pattern through the period. An anticyclone will drift eastward to southeastward over the Great Lakes, poleward of a broad belt of low heights and several embedded vorticity maxima extending from the lower Mississippi Valley to offshore from the Carolinas. One of those perturbations will be the decaying remnants of a merger of a midlatitude mid/upper low with the remnants of Francine. This feature is forecast to drift erratically eastward to southeastward over the Mid-South, contributing to convective potential over a broad area of the Southeast, but with wind fields and lift too weak to support organized severe potential. Farther west, synoptic-scale height rises are forecast across most of the central/northern Plains, as a strong trough digs south- southeastward near the BC Coast and forms a 500-mb low near UIL at the end of the period. By then, associated cyclonic flow should cover a large part of the CONUS west of the Rockies, as well as for several hundred miles off the West Coast. The 11Z surface analysis showed a low over northern MS (associated with the remnants of Francine) with an occluded front arching across AL to a triple point near MGM, a warm front across southern GA, and a cold front across the western FL Panhandle. These boundaries should become more diffuse with time today as the deep-layer cyclone above the low continues its gradual degradation. Meanwhile, a quasistationary front from east-central ND across central SD to southwestern NE should weaken through the day, but with a remnant trough/convergence zone lingering near the present position. A weak surface low should form farther west today, in northeastern WY east of GCC, then migrate eastward into western SD toward RAP tonight. ...North-central Plains... Isolated to scattered thunderstorms are expected to develop this afternoon, in a narrow corridor of relatively maximized low-level convergence (corresponding to the weak front/trough) and favorably strong surface heating east through southeast of the low. Isolated severe gusts and hail will be possible as convection proceeds across SD and perhaps into southern ND this evening, before encountering progressively more-stable low-level conditions with a decreasing severe threat. A weak perturbation apparent in moisture-channel imagery over east-central WY should move northeastward across the western NE Panhandle to southwestern/south-central SD by mid/late afternoon, and may contribute subtle large-scale ascent to the environment. Still, with broader, ambient height rises superimposed on that, considerable mesoscale timing/location uncertainty remains on the most probable initiation zone within the southern part of the outlook area. The later initiation occurs, the farther north the unconditional severe-threat area will be. Activity should move north-northeastward into a corridor of favorable moisture and buoyancy, with peak MLCAPE in the 500-1500 J/kg range, atop a well-mixed subcloud layer. Greater lift and more backing of low level flow will be present over the SD part of the outlook, spreading northward into southern ND with time this evening, and supporting conditional potential for upscale growth of activity initiating in a hotter boundary layer near the Badlands. Stronger capping and weaker convergence over western NE cast some doubt as to formation and convective coverage in the Sandhills, though the environment will be favorable for marginal severe there as well. Modest low/middle-level winds nonetheless will veer strongly with height, leading to 25-35-kt effective-shear magnitudes in support of some organization. ..Edwards/Mosier.. 09/14/2024 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0742 AM CDT Sat Sep 14 2024 Valid 141300Z - 151200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS OVER PARTS OF THE NORTH-CENTRAL PLAINS... ...SUMMARY... Thunderstorms capable of isolated severe gusts and hail will be possible over parts of the north-central Plains. ...Synopsis... Blockiness in the eastern CONUS will continue to dominate the large-scale, mid/upper-level pattern through the period. An anticyclone will drift eastward to southeastward over the Great Lakes, poleward of a broad belt of low heights and several embedded vorticity maxima extending from the lower Mississippi Valley to offshore from the Carolinas. One of those perturbations will be the decaying remnants of a merger of a midlatitude mid/upper low with the remnants of Francine. This feature is forecast to drift erratically eastward to southeastward over the Mid-South, contributing to convective potential over a broad area of the Southeast, but with wind fields and lift too weak to support organized severe potential. Farther west, synoptic-scale height rises are forecast across most of the central/northern Plains, as a strong trough digs south- southeastward near the BC Coast and forms a 500-mb low near UIL at the end of the period. By then, associated cyclonic flow should cover a large part of the CONUS west of the Rockies, as well as for several hundred miles off the West Coast. The 11Z surface analysis showed a low over northern MS (associated with the remnants of Francine) with an occluded front arching across AL to a triple point near MGM, a warm front across southern GA, and a cold front across the western FL Panhandle. These boundaries should become more diffuse with time today as the deep-layer cyclone above the low continues its gradual degradation. Meanwhile, a quasistationary front from east-central ND across central SD to southwestern NE should weaken through the day, but with a remnant trough/convergence zone lingering near the present position. A weak surface low should form farther west today, in northeastern WY east of GCC, then migrate eastward into western SD toward RAP tonight. ...North-central Plains... Isolated to scattered thunderstorms are expected to develop this afternoon, in a narrow corridor of relatively maximized low-level convergence (corresponding to the weak front/trough) and favorably strong surface heating east through southeast of the low. Isolated severe gusts and hail will be possible as convection proceeds across SD and perhaps into southern ND this evening, before encountering progressively more-stable low-level conditions with a decreasing severe threat. A weak perturbation apparent in moisture-channel imagery over east-central WY should move northeastward across the western NE Panhandle to southwestern/south-central SD by mid/late afternoon, and may contribute subtle large-scale ascent to the environment. Still, with broader, ambient height rises superimposed on that, considerable mesoscale timing/location uncertainty remains on the most probable initiation zone within the southern part of the outlook area. The later initiation occurs, the farther north the unconditional severe-threat area will be. Activity should move north-northeastward into a corridor of favorable moisture and buoyancy, with peak MLCAPE in the 500-1500 J/kg range, atop a well-mixed subcloud layer. Greater lift and more backing of low level flow will be present over the SD part of the outlook, spreading northward into southern ND with time this evening, and supporting conditional potential for upscale growth of activity initiating in a hotter boundary layer near the Badlands. Stronger capping and weaker convergence over western NE cast some doubt as to formation and convective coverage in the Sandhills, though the environment will be favorable for marginal severe there as well. Modest low/middle-level winds nonetheless will veer strongly with height, leading to 25-35-kt effective-shear magnitudes in support of some organization. ..Edwards/Mosier.. 09/14/2024 Read more

5-Day Uncertainty Track last updated Sat, 14 Sep 2024 11:39:51 GMT


Wind Speed Probabilities last updated Sat, 14 Sep 2024 09:28:47 GMT

Issued at 500 AM MST Sat Sep 14 2024 000 WTPZ34 KNHC 141137 TCPEP4 BULLETIN Tropical Storm Ileana Intermediate Advisory Number 8A NWS National Hurricane Center Miami FL EP092024 500 AM MST Sat Sep 14 2024 ...ILEANA CONTINUES NORTHWARD OVER THE SOUTHERN GULF OF CALIFORNIA... ...TROPICAL STORM CONDITIONS OCCURRING ALONG PORTIONS OF THE COAST OF MEXICO... SUMMARY OF 500 AM MST...1200 UTC...INFORMATION ---------------------------------------------- LOCATION...24.7N 109.2W ABOUT 70 MI...110 KM S OF LOS MOCHIS MEXICO ABOUT 85 MI...135 KM ENE OF LA PAZ MEXICO MAXIMUM SUSTAINED WINDS...40 MPH...65 KM/H PRESENT MOVEMENT...N OR 360 DEGREES AT 7 MPH...11 KM/H MINIMUM CENTRAL PRESSURE...1003 MB...29.62 INCHES WATCHES AND WARNINGS -------------------- CHANGES WITH THIS ADVISORY: None. SUMMARY OF WATCHES AND WARNINGS IN EFFECT: A Tropical Storm Warning is in effect for... * Altata to Huatabampito Mexico A Tropical Storm Warning means that tropical storm conditions are expected somewhere within the warning area, in this case within 12 hours. Interests elsewhere in the Mexican states of Baja California Sur, Sinaloa, and Sonora should closely monitor the progress of Ileana. For storm information specific to your area, please monitor products issued by your national meteorological service. DISCUSSION AND OUTLOOK ---------------------- At 500 AM MST (1200 UTC), the center of Tropical Storm Ileana was located near latitude 24.7 North, longitude 109.2 West. Ileana is moving toward the north near 7 mph (11 km/h), and this general motion is expected to continue today. A slower motion toward the north-northwest and northwest is expected tonight and on Sunday. On the forecast track, the center of Ileana will move near or over the coasts of northern Sinaloa and southern Sonora later today, and then move over the Gulf of California roughly parallel to the coast on Sunday. Maximum sustained winds are near 40 mph (65 km/h) with higher gusts. Weakening is forecast to begin later this afternoon or evening, and Ileana is likely to degenerate into a remnant low tonight. The remnant low is expected to dissipate by early Monday. Tropical-storm-force winds extend outward up to 60 miles (95 km) from the center. The Mexican Navy station at Topolobampo recently reported sustained winds of 40 mph (65 km/h) and a wind gust of 48 mph (77 km/h). The estimated minimum central pressure is 1003 mb (29.62 inches). HAZARDS AFFECTING LAND ---------------------- Key messages for Ileana can be found in the Tropical Cyclone Discussion under AWIPS header MIATCDEP4 and WMO header WTPZ44 KNHC. RAINFALL: Tropical Storm Ileana is expected to bring rainfall of 6 to 8 inches, with localized higher amounts up to 12 inches, across northwest coastal Sinaloa through this weekend. For a complete depiction of forecast rainfall associated with Ileana, please see the National Weather Service Storm Total Rainfall Graphic, available at hurricanes.gov/graphics_ep4.shtml?rainqpf WIND: Tropical storm conditions are expected across portions of the warning area in northern Sinaloa and southern Sonora later this morning and afternoon. SURF: Swells generated by Ileana will affect portions of the Gulf of California coasts of Sinaloa, southern Sonora, and southern Baja California Sur during the next day or so. These swells could cause life-threatening surf and rip current conditions. Please consult products from your local weather office. NEXT ADVISORY ------------- Next complete advisory at 800 AM MST. $$ Forecaster Beven

...ILEANA CONTINUES NORTHWARD OVER THE SOUTHERN GULF OF CALIFORNIA... ...TROPICAL STORM CONDITIONS OCCURRING ALONG PORTIONS OF THE COAST OF MEXICO... As of 5:00 AM MST Sat Sep 14 the center of Ileana was located near 24.7, -109.2 with movement N at 7 mph. The minimum central pressure was 1003 mb with maximum sustained winds of about 40 mph.

Issued at 500 AM MST Sat Sep 14 2024 ZCZC MIATCPEP4 ALL TTAA00 KNHC DDHHMM BULLETIN Tropical Storm Ileana Intermediate Advisory Number 8A NWS National Hurricane Center Miami FL EP092024 500 AM MST Sat Sep 14 2024 ...ILEANA CONTINUES NORTHWARD OVER THE SOUTHERN GULF OF CALIFORNIA... ...TROPICAL STORM CONDITIONS OCCURRING ALONG PORTIONS OF THE COAST OF MEXICO... SUMMARY OF 500 AM MST...1200 UTC...INFORMATION ---------------------------------------------- LOCATION...24.7N 109.2W ABOUT 70 MI...110 KM S OF LOS MOCHIS MEXICO ABOUT 85 MI...135 KM ENE OF LA PAZ MEXICO MAXIMUM SUSTAINED WINDS...40 MPH...65 KM/H PRESENT MOVEMENT...N OR 360 DEGREES AT 7 MPH...11 KM/H MINIMUM CENTRAL PRESSURE...1003 MB...29.62 INCHES WATCHES AND WARNINGS -------------------- CHANGES WITH THIS ADVISORY: None. SUMMARY OF WATCHES AND WARNINGS IN EFFECT: A Tropical Storm Warning is in effect for... * Altata to Huatabampito Mexico A Tropical Storm Warning means that tropical storm conditions are expected somewhere within the warning area, in this case within 12 hours. Interests elsewhere in the Mexican states of Baja California Sur, Sinaloa, and Sonora should closely monitor the progress of Ileana. For storm information specific to your area, please monitor products issued by your national meteorological service. DISCUSSION AND OUTLOOK ---------------------- At 500 AM MST (1200 UTC), the center of Tropical Storm Ileana was located near latitude 24.7 North, longitude 109.2 West. Ileana is moving toward the north near 7 mph (11 km/h), and this general motion is expected to continue today. A slower motion toward the north-northwest and northwest is expected tonight and on Sunday. On the forecast track, the center of Ileana will move near or over the coasts of northern Sinaloa and southern Sonora later today, and then move over the Gulf of California roughly parallel to the coast on Sunday. Maximum sustained winds are near 40 mph (65 km/h) with higher gusts. Weakening is forecast to begin later this afternoon or evening, and Ileana is likely to degenerate into a remnant low tonight. The remnant low is expected to dissipate by early Monday. Tropical-storm-force winds extend outward up to 60 miles (95 km) from the center. The Mexican Navy station at Topolobampo recently reported sustained winds of 40 mph (65 km/h) and a wind gust of 48 mph (77 km/h). The estimated minimum central pressure is 1003 mb (29.62 inches). HAZARDS AFFECTING LAND ---------------------- Key messages for Ileana can be found in the Tropical Cyclone Discussion under AWIPS header MIATCDEP4 and WMO header WTPZ44 KNHC. RAINFALL: Tropical Storm Ileana is expected to bring rainfall of 6 to 8 inches, with localized higher amounts up to 12 inches, across northwest coastal Sinaloa through this weekend. For a complete depiction of forecast rainfall associated with Ileana, please see the National Weather Service Storm Total Rainfall Graphic, available at hurricanes.gov/graphics_ep4.shtml?rainqpf WIND: Tropical storm conditions are expected across portions of the warning area in northern Sinaloa and southern Sonora later this morning and afternoon. SURF: Swells generated by Ileana will affect portions of the Gulf of California coasts of Sinaloa, southern Sonora, and southern Baja California Sur during the next day or so. These swells could cause life-threatening surf and rip current conditions. Please consult products from your local weather office. NEXT ADVISORY ------------- Next complete advisory at 800 AM MST. $$ Forecaster Beven NNNN

...ILEANA CONTINUES NORTHWARD OVER THE SOUTHERN GULF OF CALIFORNIA... ...TROPICAL STORM CONDITIONS OCCURRING ALONG PORTIONS OF THE COAST OF MEXICO... As of 5:00 AM MST Sat Sep 14 the center of Ileana was located near 24.7, -109.2 with movement N at 7 mph. The minimum central pressure was 1003 mb with maximum sustained winds of about 40 mph.

5-Day Uncertainty Track last updated Sat, 14 Sep 2024 09:09:39 GMT


Wind Speed Probabilities last updated Sat, 14 Sep 2024 09:28:47 GMT

Issued at 200 AM MST Sat Sep 14 2024 000 WTPZ44 KNHC 140853 TCDEP4 Tropical Storm Ileana Discussion Number 8 NWS National Hurricane Center Miami FL EP092024 200 AM MST Sat Sep 14 2024 Ileana continues to produce bursts of deep convection, but a sharpening of the west side of the cloud canopy suggests stronger vertical shear is setting in. Maximum winds are still estimated to be 35 kt based on ASCAT data from last evening, and the fact that subjective and objective intensity estimates have not begun to decrease much quite yet. Ileana's center is moving northward over the southern Gulf of California, away from southern Baja California Sur, with an initial motion of 360/8 kt. A northward motion is expected to continue today, bringing Ileana's center near or over the coast of northern Sinaloa and southern Sonora around midday. The new NHC track forecast is a bit to the east of the previous prediction during the first 12 hours or so, mainly due to an adjustment of the initial position. The track guidance indicates that Ileana should slow down and turn north-northwestward and then northwestward tonight and on Sunday, generally running up the length of the Gulf of California. Although deep-layer shear is beginning to increase, several models, including the GFS and ECMWF, indicate that Ileana could maintain tropical storm intensity and bring tropical storm conditions to portions of the northern coast of Sinaloa and southern coast of Sonora later this morning and early afternoon. These same models, however, show Ileana's convection quickly being sheared away and dissipating by this evening and tonight as the cyclone moves into a much drier air mass. As a result, the NHC forecast shows Ileana degenerating into a remnant low in about 24 hours, with the remnant low dissipating over the central Gulf of California by early Monday. Key Messages: 1. Tropical Storm Ileana will bring heavy rainfall to portions of western Mexico through this weekend. This heavy rainfall will bring a risk of flash flooding and mudslides to portions of the area. 2. Tropical storm conditions are expected within the warning area of northern Sinaloa and southern Sonora later this morning and afternoon. FORECAST POSITIONS AND MAX WINDS INIT 14/0900Z 24.3N 109.2W 35 KT 40 MPH 12H 14/1800Z 25.1N 109.3W 35 KT 40 MPH 24H 15/0600Z 25.9N 109.7W 30 KT 35 MPH...POST-TROP/REMNT LOW 36H 15/1800Z 26.6N 110.4W 25 KT 30 MPH...POST-TROP/REMNT LOW 48H 16/0600Z 27.4N 111.2W 20 KT 25 MPH...POST-TROP/REMNT LOW 60H 16/1800Z...DISSIPATED $$ Forecaster Berg

Issued at 200 AM MST Sat Sep 14 2024 000 WTPZ34 KNHC 140852 TCPEP4 BULLETIN Tropical Storm Ileana Advisory Number 8 NWS National Hurricane Center Miami FL EP092024 200 AM MST Sat Sep 14 2024 ...ILEANA CONTINUES NORTHWARD OVER THE SOUTHERN GULF OF CALIFORNIA... ...TROPICAL STORM WARNING ISSUED FOR THE COASTS OF NORTHERN SINALOA AND EXTREME SOUTHERN SONORA... SUMMARY OF 200 AM MST...0900 UTC...INFORMATION ---------------------------------------------- LOCATION...24.3N 109.2W ABOUT 70 MI...110 KM E OF LA PAZ MEXICO ABOUT 105 MI...170 KM S OF LOS MOCHIS MEXICO MAXIMUM SUSTAINED WINDS...40 MPH...65 KM/H PRESENT MOVEMENT...N OR 360 DEGREES AT 7 MPH...11 KM/H MINIMUM CENTRAL PRESSURE...1003 MB...29.62 INCHES WATCHES AND WARNINGS -------------------- CHANGES WITH THIS ADVISORY: The government of Mexico has issued a Tropical Storm Warning along the coast of mainland Mexico from Altata to Huatabampito, and has discontinued all watches and warnings for Baja California Sur. SUMMARY OF WATCHES AND WARNINGS IN EFFECT: A Tropical Storm Warning is in effect for... * Altata to Huatabampito Mexico A Tropical Storm Warning means that tropical storm conditions are expected somewhere within the warning area, in this case within 12 hours. Interests elsewhere in the Mexican states of Baja California Sur, Sinaloa, and Sonora should closely monitor the progress of Ileana. For storm information specific to your area, please monitor products issued by your national meteorological service. DISCUSSION AND OUTLOOK ---------------------- At 200 AM MST (0900 UTC), the center of Tropical Storm Ileana was located near latitude 24.3 North, longitude 109.2 West. Ileana is moving toward the north near 7 mph (11 km/h), and this general motion is expected to continue today. A slower motion toward the north-northwest and northwest is expected tonight and on Sunday. On the forecast track, the center of Ileana will move near or over the coasts of northern Sinaloa and southern Sonora later today, and then move over the Gulf of California roughly parallel to the coast on Sunday. Maximum sustained winds are near 40 mph (65 km/h) with higher gusts. Weakening is forecast to begin later this afternoon or evening, and Ileana is likely to degenerate into a remnant low tonight. The remnant low is expected to dissipate by early Monday. Tropical-storm-force winds extend outward up to 60 miles (95 km) from the center. The estimated minimum central pressure is 1003 mb (29.62 inches). HAZARDS AFFECTING LAND ---------------------- Key messages for Ileana can be found in the Tropical Cyclone Discussion under AWIPS header MIATCDEP4 and WMO header WTPZ44 KNHC. RAINFALL: Tropical Storm Ileana is expected to bring rainfall of 6 to 8 inches, with localized higher amounts up to 12 inches, across northwest coastal Sinaloa through this weekend. For a complete depiction of forecast rainfall associated with Ileana, please see the National Weather Service Storm Total Rainfall Graphic, available at hurricanes.gov/graphics_ep4.shtml?rainqpf WIND: Tropical storm conditions are expected across portions of the warning area in northern Sinaloa and southern Sonora later this morning and afternoon. SURF: Swells generated by Ileana will affect portions of the Gulf of California coasts of Sinaloa, southern Sonora, and southern Baja California Sur during the next day or so. These swells could cause life-threatening surf and rip current conditions. Please consult products from your local weather office. NEXT ADVISORY ------------- Next intermediate advisory at 500 AM MST. Next complete advisory at 800 AM MST. $$ Forecaster Berg

...ILEANA CONTINUES NORTHWARD OVER THE SOUTHERN GULF OF CALIFORNIA... ...TROPICAL STORM WARNING ISSUED FOR THE COASTS OF NORTHERN SINALOA AND EXTREME SOUTHERN SONORA... As of 2:00 AM MST Sat Sep 14 the center of Ileana was located near 24.3, -109.2 with movement N at 7 mph. The minimum central pressure was 1003 mb with maximum sustained winds of about 40 mph.