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SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0749 AM CDT Thu Sep 18 2025 Valid 181300Z - 191200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM OK INTO THE OZARKS AND LOWER MO VALLEY...AND ACROSS PORTIONS OF SOUTHERN CA AND SOUTHWEST AZ... ...SUMMARY... Strong to locally severe storms are possible from late afternoon into tonight from parts of Oklahoma into Missouri and over small parts of adjacent states. Isolated strong to severe storms are possible across eastern southern California and southwest Arizona as well. ...Southern CA/Southwest AZ... Anomalously moist airmass associated with the remnants of tropical cyclone Mario continues to advect northward into southern CA/AZ. 12Z NKX sounding sampled a 1.95 PWAT, which is well above the 90th percentile based on SPC sounding climatology. Filtered heating is anticipated within this moist environment, resulting in moderate buoyancy across much of eastern southern CA and southwest AZ this afternoon. Moderate vertical shear is anticipated as well, particularly across eastern southern CA. Thunderstorm development is expected during the afternoon, with a predominantly multicellular mode. However, enough shear and instability are in place to support organization with any more persistent updrafts, and a few supercells capable of damaging gusts are possible. A very-low-probability tornado threat exists as well, particularly in the Lower CO Valley vicinity where some guidance suggests surface winds stay more southeasterly. Even so, the low-level flow is weak and any tornado threat should be very localized. ...Central/Southern Plains into Ozarks and Mid/Lower MO Valley... Broad upper troughing remains in place across the northern/central Plains, anchored by a pair of modest cyclones, one currently centered over central SD and the other centered over the MT/SK border vicinity. Another shortwave trough is rotating through the base of this troughing, and is forecast to progress eastward/southward into KS and northern OK today before pivoting into IA/MO/AR during tonight. Surface analysis reveals a pair of lows, one beneath the central SD cyclone and another weaker one over northeast OK. Modest troughing extends between these lows and a diffuse cold front extends southwestward from the northeast OK low into the TX South Plains. Mid 60s dewpoints currently extend through much of eastern KS and western MO. A modest eastward/southeastward push of the cold front/surface trough is expected as the shortwave trough moves into KS, with ascent attendant to these features resulting in thunderstorm development from the Mid MO Valley across eastern KS/western MO into central OK and far northwest TX. Highest coverage appears most likely from far eastern KS into western MO, northeast OK, and northwest AR. Buoyancy and shear will both be fairly modest. However, strong high-level flow may support a greater chance of hail from the TX Panhandle into OK, while the coldest midlevel temperatures also support hail from eastern KS into MO. ..Mosier/Bentley.. 09/18/2025 Read more

887
ABPZ20 KNHC 181109
TWOEP

Tropical Weather Outlook
NWS National Hurricane Center Miami FL
500 AM PDT Thu Sep 18 2025

For the eastern and central North Pacific east of 180 longitude:

Off the Coast of Southwestern Mexico (EP96):
A broad area of low pressure located a few hundred miles southwest
of the coast of southwestern Mexico is producing a large area of
showers and thunderstorms. Although a tropical depression is likely
to form during the next day or two, the system is forecast to
encounter progressively cooler oceanic surface temperatures and a
drier, stable airmass over the weekend, which should inhibit any
additional development.
*Formation chance through 48 hours...high...80 percent.
*Formation chance through 7 days...high...80 percent.

$$
Forecaster Roberts

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0249 AM CDT Thu Sep 18 2025 Valid 211200Z - 261200Z ...DISCUSSION... An upper shortwave trough is forecast to move across the northern Rockies on Day 4/Sun while low-amplitude, broad upper troughing persists across the central portion of the CONUS. By Day 5/Mon, the northern Rockies upper trough is expected to rapidly deepen as it overspread the plains. Rich boundary layer moisture if forecast to be in place across portions of the southern/central Plains into the MS Valley as a strong cold front moves across parts of the Plains. While the timing of the upper trough ejecting into the Plains is uncertain, some severe potential could develop on Day 5/Mon across the southern/central Plains toward the Mid/Lower MO Valley. Uncertainty remains too high to include 15 percent probabilities at this time however. Beyond Day 5/Mon, uncertainty increases as large spread among model guidance persists with regard to the evolution of a developing upper low somewhere over the mid-section of the CONUS into Day 8/Thu. Severe potential is uncertain, and the overall pattern may favor heavy rain over organized severe heading into Day 6/Tue, but model trends will continue to be monitored. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0249 AM CDT Thu Sep 18 2025 Valid 211200Z - 261200Z ...DISCUSSION... An upper shortwave trough is forecast to move across the northern Rockies on Day 4/Sun while low-amplitude, broad upper troughing persists across the central portion of the CONUS. By Day 5/Mon, the northern Rockies upper trough is expected to rapidly deepen as it overspread the plains. Rich boundary layer moisture if forecast to be in place across portions of the southern/central Plains into the MS Valley as a strong cold front moves across parts of the Plains. While the timing of the upper trough ejecting into the Plains is uncertain, some severe potential could develop on Day 5/Mon across the southern/central Plains toward the Mid/Lower MO Valley. Uncertainty remains too high to include 15 percent probabilities at this time however. Beyond Day 5/Mon, uncertainty increases as large spread among model guidance persists with regard to the evolution of a developing upper low somewhere over the mid-section of the CONUS into Day 8/Thu. Severe potential is uncertain, and the overall pattern may favor heavy rain over organized severe heading into Day 6/Tue, but model trends will continue to be monitored. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0249 AM CDT Thu Sep 18 2025 Valid 211200Z - 261200Z ...DISCUSSION... An upper shortwave trough is forecast to move across the northern Rockies on Day 4/Sun while low-amplitude, broad upper troughing persists across the central portion of the CONUS. By Day 5/Mon, the northern Rockies upper trough is expected to rapidly deepen as it overspread the plains. Rich boundary layer moisture if forecast to be in place across portions of the southern/central Plains into the MS Valley as a strong cold front moves across parts of the Plains. While the timing of the upper trough ejecting into the Plains is uncertain, some severe potential could develop on Day 5/Mon across the southern/central Plains toward the Mid/Lower MO Valley. Uncertainty remains too high to include 15 percent probabilities at this time however. Beyond Day 5/Mon, uncertainty increases as large spread among model guidance persists with regard to the evolution of a developing upper low somewhere over the mid-section of the CONUS into Day 8/Thu. Severe potential is uncertain, and the overall pattern may favor heavy rain over organized severe heading into Day 6/Tue, but model trends will continue to be monitored. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0249 AM CDT Thu Sep 18 2025 Valid 211200Z - 261200Z ...DISCUSSION... An upper shortwave trough is forecast to move across the northern Rockies on Day 4/Sun while low-amplitude, broad upper troughing persists across the central portion of the CONUS. By Day 5/Mon, the northern Rockies upper trough is expected to rapidly deepen as it overspread the plains. Rich boundary layer moisture if forecast to be in place across portions of the southern/central Plains into the MS Valley as a strong cold front moves across parts of the Plains. While the timing of the upper trough ejecting into the Plains is uncertain, some severe potential could develop on Day 5/Mon across the southern/central Plains toward the Mid/Lower MO Valley. Uncertainty remains too high to include 15 percent probabilities at this time however. Beyond Day 5/Mon, uncertainty increases as large spread among model guidance persists with regard to the evolution of a developing upper low somewhere over the mid-section of the CONUS into Day 8/Thu. Severe potential is uncertain, and the overall pattern may favor heavy rain over organized severe heading into Day 6/Tue, but model trends will continue to be monitored. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0249 AM CDT Thu Sep 18 2025 Valid 211200Z - 261200Z ...DISCUSSION... An upper shortwave trough is forecast to move across the northern Rockies on Day 4/Sun while low-amplitude, broad upper troughing persists across the central portion of the CONUS. By Day 5/Mon, the northern Rockies upper trough is expected to rapidly deepen as it overspread the plains. Rich boundary layer moisture if forecast to be in place across portions of the southern/central Plains into the MS Valley as a strong cold front moves across parts of the Plains. While the timing of the upper trough ejecting into the Plains is uncertain, some severe potential could develop on Day 5/Mon across the southern/central Plains toward the Mid/Lower MO Valley. Uncertainty remains too high to include 15 percent probabilities at this time however. Beyond Day 5/Mon, uncertainty increases as large spread among model guidance persists with regard to the evolution of a developing upper low somewhere over the mid-section of the CONUS into Day 8/Thu. Severe potential is uncertain, and the overall pattern may favor heavy rain over organized severe heading into Day 6/Tue, but model trends will continue to be monitored. Read more

SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0201 AM CDT Thu Sep 18 2025 Valid 201200Z - 211200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Severe thunderstorms are not forecast on Saturday. ...Synopsis... A pair of upper shortwave troughs will migrate across the northern Plains and Upper Midwest on Saturday, maintaining broad upper troughing across much of the central U.S. Late in the period, another upper shortwave trough will approach the Pacific Northwest. Overall, severe potential is expected to remain limited due to poor lapse rates and weak vertical shear. Nevertheless, upper 50s to mid 60s F dewpoints across portions of the Plains to the MS Valley will support scattered diurnal thunderstorm activity. ..Leitman.. 09/18/2025 Read more

SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0201 AM CDT Thu Sep 18 2025 Valid 201200Z - 211200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Severe thunderstorms are not forecast on Saturday. ...Synopsis... A pair of upper shortwave troughs will migrate across the northern Plains and Upper Midwest on Saturday, maintaining broad upper troughing across much of the central U.S. Late in the period, another upper shortwave trough will approach the Pacific Northwest. Overall, severe potential is expected to remain limited due to poor lapse rates and weak vertical shear. Nevertheless, upper 50s to mid 60s F dewpoints across portions of the Plains to the MS Valley will support scattered diurnal thunderstorm activity. ..Leitman.. 09/18/2025 Read more

SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0201 AM CDT Thu Sep 18 2025 Valid 201200Z - 211200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Severe thunderstorms are not forecast on Saturday. ...Synopsis... A pair of upper shortwave troughs will migrate across the northern Plains and Upper Midwest on Saturday, maintaining broad upper troughing across much of the central U.S. Late in the period, another upper shortwave trough will approach the Pacific Northwest. Overall, severe potential is expected to remain limited due to poor lapse rates and weak vertical shear. Nevertheless, upper 50s to mid 60s F dewpoints across portions of the Plains to the MS Valley will support scattered diurnal thunderstorm activity. ..Leitman.. 09/18/2025 Read more

SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0201 AM CDT Thu Sep 18 2025 Valid 201200Z - 211200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Severe thunderstorms are not forecast on Saturday. ...Synopsis... A pair of upper shortwave troughs will migrate across the northern Plains and Upper Midwest on Saturday, maintaining broad upper troughing across much of the central U.S. Late in the period, another upper shortwave trough will approach the Pacific Northwest. Overall, severe potential is expected to remain limited due to poor lapse rates and weak vertical shear. Nevertheless, upper 50s to mid 60s F dewpoints across portions of the Plains to the MS Valley will support scattered diurnal thunderstorm activity. ..Leitman.. 09/18/2025 Read more

SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0201 AM CDT Thu Sep 18 2025 Valid 201200Z - 211200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Severe thunderstorms are not forecast on Saturday. ...Synopsis... A pair of upper shortwave troughs will migrate across the northern Plains and Upper Midwest on Saturday, maintaining broad upper troughing across much of the central U.S. Late in the period, another upper shortwave trough will approach the Pacific Northwest. Overall, severe potential is expected to remain limited due to poor lapse rates and weak vertical shear. Nevertheless, upper 50s to mid 60s F dewpoints across portions of the Plains to the MS Valley will support scattered diurnal thunderstorm activity. ..Leitman.. 09/18/2025 Read more

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0149 AM CDT Thu Sep 18 2025 Valid 191200Z - 201200Z ...NO CRITICAL AREAS... ...Synopsis... A mid-level trough will traverse the Upper Mississippi Valley as a weak upper trough meanders along the West Coast tomorrow (Friday). A surface low over the Upper Mississippi Valley will encourage moist conditions across the Plains, while a benign surface pattern west of the Rockies will result in another quiescent day (fire weather wise) across the Interior West. Dry low-level conditions may persist over the Ohio Valley on Friday. However, like Day 1, the lack of a stronger surface wind field should limit the potential for wildfire spread. ..Squitieri.. 09/18/2025 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0149 AM CDT Thu Sep 18 2025 Valid 191200Z - 201200Z ...NO CRITICAL AREAS... ...Synopsis... A mid-level trough will traverse the Upper Mississippi Valley as a weak upper trough meanders along the West Coast tomorrow (Friday). A surface low over the Upper Mississippi Valley will encourage moist conditions across the Plains, while a benign surface pattern west of the Rockies will result in another quiescent day (fire weather wise) across the Interior West. Dry low-level conditions may persist over the Ohio Valley on Friday. However, like Day 1, the lack of a stronger surface wind field should limit the potential for wildfire spread. ..Squitieri.. 09/18/2025 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0149 AM CDT Thu Sep 18 2025 Valid 191200Z - 201200Z ...NO CRITICAL AREAS... ...Synopsis... A mid-level trough will traverse the Upper Mississippi Valley as a weak upper trough meanders along the West Coast tomorrow (Friday). A surface low over the Upper Mississippi Valley will encourage moist conditions across the Plains, while a benign surface pattern west of the Rockies will result in another quiescent day (fire weather wise) across the Interior West. Dry low-level conditions may persist over the Ohio Valley on Friday. However, like Day 1, the lack of a stronger surface wind field should limit the potential for wildfire spread. ..Squitieri.. 09/18/2025 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0149 AM CDT Thu Sep 18 2025 Valid 191200Z - 201200Z ...NO CRITICAL AREAS... ...Synopsis... A mid-level trough will traverse the Upper Mississippi Valley as a weak upper trough meanders along the West Coast tomorrow (Friday). A surface low over the Upper Mississippi Valley will encourage moist conditions across the Plains, while a benign surface pattern west of the Rockies will result in another quiescent day (fire weather wise) across the Interior West. Dry low-level conditions may persist over the Ohio Valley on Friday. However, like Day 1, the lack of a stronger surface wind field should limit the potential for wildfire spread. ..Squitieri.. 09/18/2025 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0149 AM CDT Thu Sep 18 2025 Valid 191200Z - 201200Z ...NO CRITICAL AREAS... ...Synopsis... A mid-level trough will traverse the Upper Mississippi Valley as a weak upper trough meanders along the West Coast tomorrow (Friday). A surface low over the Upper Mississippi Valley will encourage moist conditions across the Plains, while a benign surface pattern west of the Rockies will result in another quiescent day (fire weather wise) across the Interior West. Dry low-level conditions may persist over the Ohio Valley on Friday. However, like Day 1, the lack of a stronger surface wind field should limit the potential for wildfire spread. ..Squitieri.. 09/18/2025 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0148 AM CDT Thu Sep 18 2025 Valid 181200Z - 191200Z ...NO CRITICAL AREAS... ...Synopsis... A mid-level trough will traverse the Plains states as a second upper trough meanders along the California coastline today. A surface low over California will encourage ample precipitation accumulations over southern parts of the state, and a surface high over the Rockies will help promote quiescent fire weather conditions over the Interior West. Dry low-level conditions will persist over the Ohio Valley today. However, the lack of an appreciable surface wind field should limit wildfire-spread potential. ..Squitieri.. 09/18/2025 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0148 AM CDT Thu Sep 18 2025 Valid 181200Z - 191200Z ...NO CRITICAL AREAS... ...Synopsis... A mid-level trough will traverse the Plains states as a second upper trough meanders along the California coastline today. A surface low over California will encourage ample precipitation accumulations over southern parts of the state, and a surface high over the Rockies will help promote quiescent fire weather conditions over the Interior West. Dry low-level conditions will persist over the Ohio Valley today. However, the lack of an appreciable surface wind field should limit wildfire-spread potential. ..Squitieri.. 09/18/2025 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0148 AM CDT Thu Sep 18 2025 Valid 181200Z - 191200Z ...NO CRITICAL AREAS... ...Synopsis... A mid-level trough will traverse the Plains states as a second upper trough meanders along the California coastline today. A surface low over California will encourage ample precipitation accumulations over southern parts of the state, and a surface high over the Rockies will help promote quiescent fire weather conditions over the Interior West. Dry low-level conditions will persist over the Ohio Valley today. However, the lack of an appreciable surface wind field should limit wildfire-spread potential. ..Squitieri.. 09/18/2025 ...Please see www.spc.noaa.gov/fire for graphic product... Read more