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SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0940 AM CST Mon Nov 13 2023 Valid 131630Z - 141200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Isolated thunderstorms appear possible along a small part of the Florida Atlantic Coast, and in the lee of Lake Ontario. ...Synopsis... Upper-ridging, coupled with a surface anticyclone centered over the OH/TN Valleys, will support mass subsidence and static stability across most of the CONUS today, limiting thunderstorm potential. A surface low and associated marginal buoyancy appear to be too far offshore from the lower TX coastline to support a threat for organized thunder, hence the removal of the general thunder line (though a lightning flash or two cannot be ruled out). Modest cooling aloft amid low-topped convection advecting off of Lake Ontario may support enough buoyancy (albeit scant) to support a couple of lightning flashes later today. Otherwise, modest warm-air advection inland across portions of the east-central FL coastline may support an isolated thunderstorm later tonight. ..Squitieri.. 11/13/2023 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0940 AM CST Mon Nov 13 2023 Valid 131630Z - 141200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Isolated thunderstorms appear possible along a small part of the Florida Atlantic Coast, and in the lee of Lake Ontario. ...Synopsis... Upper-ridging, coupled with a surface anticyclone centered over the OH/TN Valleys, will support mass subsidence and static stability across most of the CONUS today, limiting thunderstorm potential. A surface low and associated marginal buoyancy appear to be too far offshore from the lower TX coastline to support a threat for organized thunder, hence the removal of the general thunder line (though a lightning flash or two cannot be ruled out). Modest cooling aloft amid low-topped convection advecting off of Lake Ontario may support enough buoyancy (albeit scant) to support a couple of lightning flashes later today. Otherwise, modest warm-air advection inland across portions of the east-central FL coastline may support an isolated thunderstorm later tonight. ..Squitieri.. 11/13/2023 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0940 AM CST Mon Nov 13 2023 Valid 131630Z - 141200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Isolated thunderstorms appear possible along a small part of the Florida Atlantic Coast, and in the lee of Lake Ontario. ...Synopsis... Upper-ridging, coupled with a surface anticyclone centered over the OH/TN Valleys, will support mass subsidence and static stability across most of the CONUS today, limiting thunderstorm potential. A surface low and associated marginal buoyancy appear to be too far offshore from the lower TX coastline to support a threat for organized thunder, hence the removal of the general thunder line (though a lightning flash or two cannot be ruled out). Modest cooling aloft amid low-topped convection advecting off of Lake Ontario may support enough buoyancy (albeit scant) to support a couple of lightning flashes later today. Otherwise, modest warm-air advection inland across portions of the east-central FL coastline may support an isolated thunderstorm later tonight. ..Squitieri.. 11/13/2023 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0940 AM CST Mon Nov 13 2023 Valid 131630Z - 141200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Isolated thunderstorms appear possible along a small part of the Florida Atlantic Coast, and in the lee of Lake Ontario. ...Synopsis... Upper-ridging, coupled with a surface anticyclone centered over the OH/TN Valleys, will support mass subsidence and static stability across most of the CONUS today, limiting thunderstorm potential. A surface low and associated marginal buoyancy appear to be too far offshore from the lower TX coastline to support a threat for organized thunder, hence the removal of the general thunder line (though a lightning flash or two cannot be ruled out). Modest cooling aloft amid low-topped convection advecting off of Lake Ontario may support enough buoyancy (albeit scant) to support a couple of lightning flashes later today. Otherwise, modest warm-air advection inland across portions of the east-central FL coastline may support an isolated thunderstorm later tonight. ..Squitieri.. 11/13/2023 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0630 AM CST Mon Nov 13 2023 Valid 131300Z - 141200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Isolated thunderstorms appear possible along portions of the western/central Gulf Coast, a small part of the Florida Atlantic Coast, and in the lee of Lake Ontario. ...Synopsis and Discussion... Downstream of a weak mid-level trough over west TX and northern Mexico, a surface front will remain over parts of the western and northern Gulf of Mexico. Convective activity through the period will primarily remain focused along/near the front and offshore of the Gulf Coast. Still, some chance for elevated convection appears possible as the shortwave trough moves eastward across TX through tonight. Showers are ongoing this morning across parts of the FL Atlantic Coast. Poor lapse rates should inhibit most convection from becoming deep enough to support charge separation and lighting. But, an isolated thunderstorm or two may still occur though tonight in weak easterly low-level flow. A strong mid-level jet will move across the Great Lakes and Mid-Atlantic today, with rather cold mid-level temperatures overspreading the Lower Great Lakes. Corresponding steepening of lapse rates over the warmer waters of Lake Ontario and the development of weak instability may allow for isolated lighting flashes with any convection that can develop and move across parts of western NY. ..Gleason.. 11/13/2023 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0630 AM CST Mon Nov 13 2023 Valid 131300Z - 141200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Isolated thunderstorms appear possible along portions of the western/central Gulf Coast, a small part of the Florida Atlantic Coast, and in the lee of Lake Ontario. ...Synopsis and Discussion... Downstream of a weak mid-level trough over west TX and northern Mexico, a surface front will remain over parts of the western and northern Gulf of Mexico. Convective activity through the period will primarily remain focused along/near the front and offshore of the Gulf Coast. Still, some chance for elevated convection appears possible as the shortwave trough moves eastward across TX through tonight. Showers are ongoing this morning across parts of the FL Atlantic Coast. Poor lapse rates should inhibit most convection from becoming deep enough to support charge separation and lighting. But, an isolated thunderstorm or two may still occur though tonight in weak easterly low-level flow. A strong mid-level jet will move across the Great Lakes and Mid-Atlantic today, with rather cold mid-level temperatures overspreading the Lower Great Lakes. Corresponding steepening of lapse rates over the warmer waters of Lake Ontario and the development of weak instability may allow for isolated lighting flashes with any convection that can develop and move across parts of western NY. ..Gleason.. 11/13/2023 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0630 AM CST Mon Nov 13 2023 Valid 131300Z - 141200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Isolated thunderstorms appear possible along portions of the western/central Gulf Coast, a small part of the Florida Atlantic Coast, and in the lee of Lake Ontario. ...Synopsis and Discussion... Downstream of a weak mid-level trough over west TX and northern Mexico, a surface front will remain over parts of the western and northern Gulf of Mexico. Convective activity through the period will primarily remain focused along/near the front and offshore of the Gulf Coast. Still, some chance for elevated convection appears possible as the shortwave trough moves eastward across TX through tonight. Showers are ongoing this morning across parts of the FL Atlantic Coast. Poor lapse rates should inhibit most convection from becoming deep enough to support charge separation and lighting. But, an isolated thunderstorm or two may still occur though tonight in weak easterly low-level flow. A strong mid-level jet will move across the Great Lakes and Mid-Atlantic today, with rather cold mid-level temperatures overspreading the Lower Great Lakes. Corresponding steepening of lapse rates over the warmer waters of Lake Ontario and the development of weak instability may allow for isolated lighting flashes with any convection that can develop and move across parts of western NY. ..Gleason.. 11/13/2023 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0630 AM CST Mon Nov 13 2023 Valid 131300Z - 141200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Isolated thunderstorms appear possible along portions of the western/central Gulf Coast, a small part of the Florida Atlantic Coast, and in the lee of Lake Ontario. ...Synopsis and Discussion... Downstream of a weak mid-level trough over west TX and northern Mexico, a surface front will remain over parts of the western and northern Gulf of Mexico. Convective activity through the period will primarily remain focused along/near the front and offshore of the Gulf Coast. Still, some chance for elevated convection appears possible as the shortwave trough moves eastward across TX through tonight. Showers are ongoing this morning across parts of the FL Atlantic Coast. Poor lapse rates should inhibit most convection from becoming deep enough to support charge separation and lighting. But, an isolated thunderstorm or two may still occur though tonight in weak easterly low-level flow. A strong mid-level jet will move across the Great Lakes and Mid-Atlantic today, with rather cold mid-level temperatures overspreading the Lower Great Lakes. Corresponding steepening of lapse rates over the warmer waters of Lake Ontario and the development of weak instability may allow for isolated lighting flashes with any convection that can develop and move across parts of western NY. ..Gleason.. 11/13/2023 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0630 AM CST Mon Nov 13 2023 Valid 131300Z - 141200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Isolated thunderstorms appear possible along portions of the western/central Gulf Coast, a small part of the Florida Atlantic Coast, and in the lee of Lake Ontario. ...Synopsis and Discussion... Downstream of a weak mid-level trough over west TX and northern Mexico, a surface front will remain over parts of the western and northern Gulf of Mexico. Convective activity through the period will primarily remain focused along/near the front and offshore of the Gulf Coast. Still, some chance for elevated convection appears possible as the shortwave trough moves eastward across TX through tonight. Showers are ongoing this morning across parts of the FL Atlantic Coast. Poor lapse rates should inhibit most convection from becoming deep enough to support charge separation and lighting. But, an isolated thunderstorm or two may still occur though tonight in weak easterly low-level flow. A strong mid-level jet will move across the Great Lakes and Mid-Atlantic today, with rather cold mid-level temperatures overspreading the Lower Great Lakes. Corresponding steepening of lapse rates over the warmer waters of Lake Ontario and the development of weak instability may allow for isolated lighting flashes with any convection that can develop and move across parts of western NY. ..Gleason.. 11/13/2023 Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0343 AM CST Mon Nov 13 2023 Valid 161200Z - 211200Z ...DISCUSSION... As the southern-stream mid/upper-level trough discussed in the day-2 and day-3 outlooks approaches FL day 4, with a frontal zone moving slowly northward over portions of the peninsula, thunder potential should increase. However, deep shear and low-level lift each appear on the low part of the spectrum, suggesting any severe potential near the front would be conditional and probably marginal. The shortwave trough should pass FL thereafter. A cut-off cyclone should remain off the CA Coast into day 5/18th-19th, before height falls to the north and northwest encourage inland movement. Progs thereafter show great variability in the amplitude and geometry of this system as it moves across the southwestern and eventually south-central CONUS. Meanwhile, low-level ridging within a slowly modifying continental/polar air mass will prevail over the south-central CONUS, east of or beneath 500-mb anticyclonic flow, through at least most of day 5. This should preclude favorable moisture return for severe potential ahead of the Pacific perturbation. The stronger, more-favorable ECMWF, along with a small minority of GEFS members that are in closest mid/upper pattern agreement with it, indicate some severe potential may develop over the south-central CONUS day 6/19th-20th or day 7/20th-21st, then shift eastward into the Southeast thereafter. At this time, too much spread exists in guidance to outline specific 15% unconditional severe area(s). Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0343 AM CST Mon Nov 13 2023 Valid 161200Z - 211200Z ...DISCUSSION... As the southern-stream mid/upper-level trough discussed in the day-2 and day-3 outlooks approaches FL day 4, with a frontal zone moving slowly northward over portions of the peninsula, thunder potential should increase. However, deep shear and low-level lift each appear on the low part of the spectrum, suggesting any severe potential near the front would be conditional and probably marginal. The shortwave trough should pass FL thereafter. A cut-off cyclone should remain off the CA Coast into day 5/18th-19th, before height falls to the north and northwest encourage inland movement. Progs thereafter show great variability in the amplitude and geometry of this system as it moves across the southwestern and eventually south-central CONUS. Meanwhile, low-level ridging within a slowly modifying continental/polar air mass will prevail over the south-central CONUS, east of or beneath 500-mb anticyclonic flow, through at least most of day 5. This should preclude favorable moisture return for severe potential ahead of the Pacific perturbation. The stronger, more-favorable ECMWF, along with a small minority of GEFS members that are in closest mid/upper pattern agreement with it, indicate some severe potential may develop over the south-central CONUS day 6/19th-20th or day 7/20th-21st, then shift eastward into the Southeast thereafter. At this time, too much spread exists in guidance to outline specific 15% unconditional severe area(s). Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0343 AM CST Mon Nov 13 2023 Valid 161200Z - 211200Z ...DISCUSSION... As the southern-stream mid/upper-level trough discussed in the day-2 and day-3 outlooks approaches FL day 4, with a frontal zone moving slowly northward over portions of the peninsula, thunder potential should increase. However, deep shear and low-level lift each appear on the low part of the spectrum, suggesting any severe potential near the front would be conditional and probably marginal. The shortwave trough should pass FL thereafter. A cut-off cyclone should remain off the CA Coast into day 5/18th-19th, before height falls to the north and northwest encourage inland movement. Progs thereafter show great variability in the amplitude and geometry of this system as it moves across the southwestern and eventually south-central CONUS. Meanwhile, low-level ridging within a slowly modifying continental/polar air mass will prevail over the south-central CONUS, east of or beneath 500-mb anticyclonic flow, through at least most of day 5. This should preclude favorable moisture return for severe potential ahead of the Pacific perturbation. The stronger, more-favorable ECMWF, along with a small minority of GEFS members that are in closest mid/upper pattern agreement with it, indicate some severe potential may develop over the south-central CONUS day 6/19th-20th or day 7/20th-21st, then shift eastward into the Southeast thereafter. At this time, too much spread exists in guidance to outline specific 15% unconditional severe area(s). Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0343 AM CST Mon Nov 13 2023 Valid 161200Z - 211200Z ...DISCUSSION... As the southern-stream mid/upper-level trough discussed in the day-2 and day-3 outlooks approaches FL day 4, with a frontal zone moving slowly northward over portions of the peninsula, thunder potential should increase. However, deep shear and low-level lift each appear on the low part of the spectrum, suggesting any severe potential near the front would be conditional and probably marginal. The shortwave trough should pass FL thereafter. A cut-off cyclone should remain off the CA Coast into day 5/18th-19th, before height falls to the north and northwest encourage inland movement. Progs thereafter show great variability in the amplitude and geometry of this system as it moves across the southwestern and eventually south-central CONUS. Meanwhile, low-level ridging within a slowly modifying continental/polar air mass will prevail over the south-central CONUS, east of or beneath 500-mb anticyclonic flow, through at least most of day 5. This should preclude favorable moisture return for severe potential ahead of the Pacific perturbation. The stronger, more-favorable ECMWF, along with a small minority of GEFS members that are in closest mid/upper pattern agreement with it, indicate some severe potential may develop over the south-central CONUS day 6/19th-20th or day 7/20th-21st, then shift eastward into the Southeast thereafter. At this time, too much spread exists in guidance to outline specific 15% unconditional severe area(s). Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0343 AM CST Mon Nov 13 2023 Valid 161200Z - 211200Z ...DISCUSSION... As the southern-stream mid/upper-level trough discussed in the day-2 and day-3 outlooks approaches FL day 4, with a frontal zone moving slowly northward over portions of the peninsula, thunder potential should increase. However, deep shear and low-level lift each appear on the low part of the spectrum, suggesting any severe potential near the front would be conditional and probably marginal. The shortwave trough should pass FL thereafter. A cut-off cyclone should remain off the CA Coast into day 5/18th-19th, before height falls to the north and northwest encourage inland movement. Progs thereafter show great variability in the amplitude and geometry of this system as it moves across the southwestern and eventually south-central CONUS. Meanwhile, low-level ridging within a slowly modifying continental/polar air mass will prevail over the south-central CONUS, east of or beneath 500-mb anticyclonic flow, through at least most of day 5. This should preclude favorable moisture return for severe potential ahead of the Pacific perturbation. The stronger, more-favorable ECMWF, along with a small minority of GEFS members that are in closest mid/upper pattern agreement with it, indicate some severe potential may develop over the south-central CONUS day 6/19th-20th or day 7/20th-21st, then shift eastward into the Southeast thereafter. At this time, too much spread exists in guidance to outline specific 15% unconditional severe area(s). Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0343 AM CST Mon Nov 13 2023 Valid 161200Z - 211200Z ...DISCUSSION... As the southern-stream mid/upper-level trough discussed in the day-2 and day-3 outlooks approaches FL day 4, with a frontal zone moving slowly northward over portions of the peninsula, thunder potential should increase. However, deep shear and low-level lift each appear on the low part of the spectrum, suggesting any severe potential near the front would be conditional and probably marginal. The shortwave trough should pass FL thereafter. A cut-off cyclone should remain off the CA Coast into day 5/18th-19th, before height falls to the north and northwest encourage inland movement. Progs thereafter show great variability in the amplitude and geometry of this system as it moves across the southwestern and eventually south-central CONUS. Meanwhile, low-level ridging within a slowly modifying continental/polar air mass will prevail over the south-central CONUS, east of or beneath 500-mb anticyclonic flow, through at least most of day 5. This should preclude favorable moisture return for severe potential ahead of the Pacific perturbation. The stronger, more-favorable ECMWF, along with a small minority of GEFS members that are in closest mid/upper pattern agreement with it, indicate some severe potential may develop over the south-central CONUS day 6/19th-20th or day 7/20th-21st, then shift eastward into the Southeast thereafter. At this time, too much spread exists in guidance to outline specific 15% unconditional severe area(s). Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0343 AM CST Mon Nov 13 2023 Valid 161200Z - 211200Z ...DISCUSSION... As the southern-stream mid/upper-level trough discussed in the day-2 and day-3 outlooks approaches FL day 4, with a frontal zone moving slowly northward over portions of the peninsula, thunder potential should increase. However, deep shear and low-level lift each appear on the low part of the spectrum, suggesting any severe potential near the front would be conditional and probably marginal. The shortwave trough should pass FL thereafter. A cut-off cyclone should remain off the CA Coast into day 5/18th-19th, before height falls to the north and northwest encourage inland movement. Progs thereafter show great variability in the amplitude and geometry of this system as it moves across the southwestern and eventually south-central CONUS. Meanwhile, low-level ridging within a slowly modifying continental/polar air mass will prevail over the south-central CONUS, east of or beneath 500-mb anticyclonic flow, through at least most of day 5. This should preclude favorable moisture return for severe potential ahead of the Pacific perturbation. The stronger, more-favorable ECMWF, along with a small minority of GEFS members that are in closest mid/upper pattern agreement with it, indicate some severe potential may develop over the south-central CONUS day 6/19th-20th or day 7/20th-21st, then shift eastward into the Southeast thereafter. At this time, too much spread exists in guidance to outline specific 15% unconditional severe area(s). Read more

SPC 0830Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0205 AM CST Mon Nov 13 2023 Valid 151200Z - 161200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Thunderstorms are possible from the central Gulf Coast States to portions of Florida. ...Synopsis... A mid/upper-level split-flow pattern will remain over the CONUS, with a fast, nearly zonal northern stream near the Canadian border remaining too detached from enough moisture/instability to support a deep-convective threat. In the southern stream, a perturbation now over Chihuahua should move eastward slowly across the central Gulf Coast States and north-central Gulf through the period. An embedded 500-mb low may move approximately along I-10 from southeastern LA to the western FL Panhandle. The corresponding surface-850-mb low should begin the period near the mouth of the Mississippi River, then shift eastward along a slowly northward-moving baroclinic zone. The surface warm front is progged to remain south of the northern Gulf Coast, extending southeastward to near southernmost mainland FL early, then drifting northward. Meanwhile a cold front should move eastward across the central Gulf south of the low. A corridor of well-modified boundary-layer air is expected to shift eastward across the east-central/northeastern Gulf, parallel to and ahead of the cold front, with theta-e optimized by marine thermal/ moisture fluxes over and near the Loop Current. This may support considerable convection over the open Gulf, including scattered thunderstorms. However, surface theta-e will diminish eastward/ northeastward through the warm-frontal zone and be relatively minimized across the inland FL Peninsula through the period. This, the slow timing of the wave aloft and associated surface frontal progressions, and weak deep shear where surface-based lift may occur, suggest any overland severe threat is too conditional and low-end to include in an outlook for now. Thunder potential with elevated convection will exist over parts of the central Gulf Coast States southeastward across parts of FL through the period, including near the surface front. Coverage may be greatest over parts of MS/AL where clusters of thunderstorms are possible, rooted in a persistent low-level warm-advection/moisture-transport regime poleward of the low-level cyclone track. ..Edwards.. 11/13/2023 Read more

SPC 0830Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0205 AM CST Mon Nov 13 2023 Valid 151200Z - 161200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Thunderstorms are possible from the central Gulf Coast States to portions of Florida. ...Synopsis... A mid/upper-level split-flow pattern will remain over the CONUS, with a fast, nearly zonal northern stream near the Canadian border remaining too detached from enough moisture/instability to support a deep-convective threat. In the southern stream, a perturbation now over Chihuahua should move eastward slowly across the central Gulf Coast States and north-central Gulf through the period. An embedded 500-mb low may move approximately along I-10 from southeastern LA to the western FL Panhandle. The corresponding surface-850-mb low should begin the period near the mouth of the Mississippi River, then shift eastward along a slowly northward-moving baroclinic zone. The surface warm front is progged to remain south of the northern Gulf Coast, extending southeastward to near southernmost mainland FL early, then drifting northward. Meanwhile a cold front should move eastward across the central Gulf south of the low. A corridor of well-modified boundary-layer air is expected to shift eastward across the east-central/northeastern Gulf, parallel to and ahead of the cold front, with theta-e optimized by marine thermal/ moisture fluxes over and near the Loop Current. This may support considerable convection over the open Gulf, including scattered thunderstorms. However, surface theta-e will diminish eastward/ northeastward through the warm-frontal zone and be relatively minimized across the inland FL Peninsula through the period. This, the slow timing of the wave aloft and associated surface frontal progressions, and weak deep shear where surface-based lift may occur, suggest any overland severe threat is too conditional and low-end to include in an outlook for now. Thunder potential with elevated convection will exist over parts of the central Gulf Coast States southeastward across parts of FL through the period, including near the surface front. Coverage may be greatest over parts of MS/AL where clusters of thunderstorms are possible, rooted in a persistent low-level warm-advection/moisture-transport regime poleward of the low-level cyclone track. ..Edwards.. 11/13/2023 Read more

SPC 0830Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0205 AM CST Mon Nov 13 2023 Valid 151200Z - 161200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Thunderstorms are possible from the central Gulf Coast States to portions of Florida. ...Synopsis... A mid/upper-level split-flow pattern will remain over the CONUS, with a fast, nearly zonal northern stream near the Canadian border remaining too detached from enough moisture/instability to support a deep-convective threat. In the southern stream, a perturbation now over Chihuahua should move eastward slowly across the central Gulf Coast States and north-central Gulf through the period. An embedded 500-mb low may move approximately along I-10 from southeastern LA to the western FL Panhandle. The corresponding surface-850-mb low should begin the period near the mouth of the Mississippi River, then shift eastward along a slowly northward-moving baroclinic zone. The surface warm front is progged to remain south of the northern Gulf Coast, extending southeastward to near southernmost mainland FL early, then drifting northward. Meanwhile a cold front should move eastward across the central Gulf south of the low. A corridor of well-modified boundary-layer air is expected to shift eastward across the east-central/northeastern Gulf, parallel to and ahead of the cold front, with theta-e optimized by marine thermal/ moisture fluxes over and near the Loop Current. This may support considerable convection over the open Gulf, including scattered thunderstorms. However, surface theta-e will diminish eastward/ northeastward through the warm-frontal zone and be relatively minimized across the inland FL Peninsula through the period. This, the slow timing of the wave aloft and associated surface frontal progressions, and weak deep shear where surface-based lift may occur, suggest any overland severe threat is too conditional and low-end to include in an outlook for now. Thunder potential with elevated convection will exist over parts of the central Gulf Coast States southeastward across parts of FL through the period, including near the surface front. Coverage may be greatest over parts of MS/AL where clusters of thunderstorms are possible, rooted in a persistent low-level warm-advection/moisture-transport regime poleward of the low-level cyclone track. ..Edwards.. 11/13/2023 Read more

SPC 0830Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0205 AM CST Mon Nov 13 2023 Valid 151200Z - 161200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Thunderstorms are possible from the central Gulf Coast States to portions of Florida. ...Synopsis... A mid/upper-level split-flow pattern will remain over the CONUS, with a fast, nearly zonal northern stream near the Canadian border remaining too detached from enough moisture/instability to support a deep-convective threat. In the southern stream, a perturbation now over Chihuahua should move eastward slowly across the central Gulf Coast States and north-central Gulf through the period. An embedded 500-mb low may move approximately along I-10 from southeastern LA to the western FL Panhandle. The corresponding surface-850-mb low should begin the period near the mouth of the Mississippi River, then shift eastward along a slowly northward-moving baroclinic zone. The surface warm front is progged to remain south of the northern Gulf Coast, extending southeastward to near southernmost mainland FL early, then drifting northward. Meanwhile a cold front should move eastward across the central Gulf south of the low. A corridor of well-modified boundary-layer air is expected to shift eastward across the east-central/northeastern Gulf, parallel to and ahead of the cold front, with theta-e optimized by marine thermal/ moisture fluxes over and near the Loop Current. This may support considerable convection over the open Gulf, including scattered thunderstorms. However, surface theta-e will diminish eastward/ northeastward through the warm-frontal zone and be relatively minimized across the inland FL Peninsula through the period. This, the slow timing of the wave aloft and associated surface frontal progressions, and weak deep shear where surface-based lift may occur, suggest any overland severe threat is too conditional and low-end to include in an outlook for now. Thunder potential with elevated convection will exist over parts of the central Gulf Coast States southeastward across parts of FL through the period, including near the surface front. Coverage may be greatest over parts of MS/AL where clusters of thunderstorms are possible, rooted in a persistent low-level warm-advection/moisture-transport regime poleward of the low-level cyclone track. ..Edwards.. 11/13/2023 Read more