SPC Aug 12, 2025 1630 UTC Day 1 Convective Outlook

1 week 6 days ago
SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1128 AM CDT Tue Aug 12 2025 Valid 121630Z - 131200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FOR PORTIONS OF THE GREAT LAKES AND SOUTHEAST ARIZONA INTO SOUTHWEST NEW MEXICO... ...SUMMARY... Strong to locally severe thunderstorms are possible over parts of the Great Lakes/Midwest this afternoon with both damaging winds and hail possible. Gusty winds may also occur over southeast Arizona and southwest New Mexico. ...Great Lakes/Midwest... Midday satellite/radar composite show a weakened thunderstorm band moving east-northeast across the eastern part of Lower MI. Surface analysis indicates rain-cooled air north of a gust front/outflow that has become draped from southeast Lower MI into the Michiana region. Heating south of this boundary has resulted in temperatures warming through the mid-upper 80s with dewpoints in the lower 70s. Additional storms will probably develop along the trailing outflow and gradually move east-northeast with the mean wind. Considerably weaker deep-layer shear is present across the eastern part of the Corn Belt into the Lower MI vicinity compared to farther north over the U.P. of MI in closer proximity to a shortwave trough. Nonetheless, scattered thunderstorms will gradually develop within a moist/destabilizing airmass and pose a risk for isolated strong to perhaps locally severe/damaging gusts this afternoon. Farther north in WI into the U.P. of MI, a weak cold front will move into the region later this afternoon. Model guidance shows widely scattered storms developing as filtered sunshine leads to a destabilizing boundary layer. A few stronger thunderstorms are possible and could yield a localized risk for marginally severe hail and damaging gusts during the mid afternoon to early evening period. ...Southeast AZ/southwest NM... Strong heating should result in widely scattered thunderstorms developing near terrain-favored areas. Weak shear will result in disorganized storms, but the development of very steep surface to 500-mb lapse rates will promote strong evaporative cooling with the more intense downdrafts. Isolated severe gusts are possible. ..Smith/Squitieri.. 08/12/2025 Read more

SPC Aug 12, 2025 1630 UTC Day 1 Convective Outlook

1 week 6 days ago
SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1128 AM CDT Tue Aug 12 2025 Valid 121630Z - 131200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FOR PORTIONS OF THE GREAT LAKES AND SOUTHEAST ARIZONA INTO SOUTHWEST NEW MEXICO... ...SUMMARY... Strong to locally severe thunderstorms are possible over parts of the Great Lakes/Midwest this afternoon with both damaging winds and hail possible. Gusty winds may also occur over southeast Arizona and southwest New Mexico. ...Great Lakes/Midwest... Midday satellite/radar composite show a weakened thunderstorm band moving east-northeast across the eastern part of Lower MI. Surface analysis indicates rain-cooled air north of a gust front/outflow that has become draped from southeast Lower MI into the Michiana region. Heating south of this boundary has resulted in temperatures warming through the mid-upper 80s with dewpoints in the lower 70s. Additional storms will probably develop along the trailing outflow and gradually move east-northeast with the mean wind. Considerably weaker deep-layer shear is present across the eastern part of the Corn Belt into the Lower MI vicinity compared to farther north over the U.P. of MI in closer proximity to a shortwave trough. Nonetheless, scattered thunderstorms will gradually develop within a moist/destabilizing airmass and pose a risk for isolated strong to perhaps locally severe/damaging gusts this afternoon. Farther north in WI into the U.P. of MI, a weak cold front will move into the region later this afternoon. Model guidance shows widely scattered storms developing as filtered sunshine leads to a destabilizing boundary layer. A few stronger thunderstorms are possible and could yield a localized risk for marginally severe hail and damaging gusts during the mid afternoon to early evening period. ...Southeast AZ/southwest NM... Strong heating should result in widely scattered thunderstorms developing near terrain-favored areas. Weak shear will result in disorganized storms, but the development of very steep surface to 500-mb lapse rates will promote strong evaporative cooling with the more intense downdrafts. Isolated severe gusts are possible. ..Smith/Squitieri.. 08/12/2025 Read more

SPC Aug 12, 2025 1630 UTC Day 1 Convective Outlook

1 week 6 days ago
SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1128 AM CDT Tue Aug 12 2025 Valid 121630Z - 131200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FOR PORTIONS OF THE GREAT LAKES AND SOUTHEAST ARIZONA INTO SOUTHWEST NEW MEXICO... ...SUMMARY... Strong to locally severe thunderstorms are possible over parts of the Great Lakes/Midwest this afternoon with both damaging winds and hail possible. Gusty winds may also occur over southeast Arizona and southwest New Mexico. ...Great Lakes/Midwest... Midday satellite/radar composite show a weakened thunderstorm band moving east-northeast across the eastern part of Lower MI. Surface analysis indicates rain-cooled air north of a gust front/outflow that has become draped from southeast Lower MI into the Michiana region. Heating south of this boundary has resulted in temperatures warming through the mid-upper 80s with dewpoints in the lower 70s. Additional storms will probably develop along the trailing outflow and gradually move east-northeast with the mean wind. Considerably weaker deep-layer shear is present across the eastern part of the Corn Belt into the Lower MI vicinity compared to farther north over the U.P. of MI in closer proximity to a shortwave trough. Nonetheless, scattered thunderstorms will gradually develop within a moist/destabilizing airmass and pose a risk for isolated strong to perhaps locally severe/damaging gusts this afternoon. Farther north in WI into the U.P. of MI, a weak cold front will move into the region later this afternoon. Model guidance shows widely scattered storms developing as filtered sunshine leads to a destabilizing boundary layer. A few stronger thunderstorms are possible and could yield a localized risk for marginally severe hail and damaging gusts during the mid afternoon to early evening period. ...Southeast AZ/southwest NM... Strong heating should result in widely scattered thunderstorms developing near terrain-favored areas. Weak shear will result in disorganized storms, but the development of very steep surface to 500-mb lapse rates will promote strong evaporative cooling with the more intense downdrafts. Isolated severe gusts are possible. ..Smith/Squitieri.. 08/12/2025 Read more

SPC Aug 12, 2025 1630 UTC Day 1 Convective Outlook

1 week 6 days ago
SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1128 AM CDT Tue Aug 12 2025 Valid 121630Z - 131200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FOR PORTIONS OF THE GREAT LAKES AND SOUTHEAST ARIZONA INTO SOUTHWEST NEW MEXICO... ...SUMMARY... Strong to locally severe thunderstorms are possible over parts of the Great Lakes/Midwest this afternoon with both damaging winds and hail possible. Gusty winds may also occur over southeast Arizona and southwest New Mexico. ...Great Lakes/Midwest... Midday satellite/radar composite show a weakened thunderstorm band moving east-northeast across the eastern part of Lower MI. Surface analysis indicates rain-cooled air north of a gust front/outflow that has become draped from southeast Lower MI into the Michiana region. Heating south of this boundary has resulted in temperatures warming through the mid-upper 80s with dewpoints in the lower 70s. Additional storms will probably develop along the trailing outflow and gradually move east-northeast with the mean wind. Considerably weaker deep-layer shear is present across the eastern part of the Corn Belt into the Lower MI vicinity compared to farther north over the U.P. of MI in closer proximity to a shortwave trough. Nonetheless, scattered thunderstorms will gradually develop within a moist/destabilizing airmass and pose a risk for isolated strong to perhaps locally severe/damaging gusts this afternoon. Farther north in WI into the U.P. of MI, a weak cold front will move into the region later this afternoon. Model guidance shows widely scattered storms developing as filtered sunshine leads to a destabilizing boundary layer. A few stronger thunderstorms are possible and could yield a localized risk for marginally severe hail and damaging gusts during the mid afternoon to early evening period. ...Southeast AZ/southwest NM... Strong heating should result in widely scattered thunderstorms developing near terrain-favored areas. Weak shear will result in disorganized storms, but the development of very steep surface to 500-mb lapse rates will promote strong evaporative cooling with the more intense downdrafts. Isolated severe gusts are possible. ..Smith/Squitieri.. 08/12/2025 Read more

SPC Aug 12, 2025 1630 UTC Day 1 Convective Outlook

1 week 6 days ago
SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1128 AM CDT Tue Aug 12 2025 Valid 121630Z - 131200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FOR PORTIONS OF THE GREAT LAKES AND SOUTHEAST ARIZONA INTO SOUTHWEST NEW MEXICO... ...SUMMARY... Strong to locally severe thunderstorms are possible over parts of the Great Lakes/Midwest this afternoon with both damaging winds and hail possible. Gusty winds may also occur over southeast Arizona and southwest New Mexico. ...Great Lakes/Midwest... Midday satellite/radar composite show a weakened thunderstorm band moving east-northeast across the eastern part of Lower MI. Surface analysis indicates rain-cooled air north of a gust front/outflow that has become draped from southeast Lower MI into the Michiana region. Heating south of this boundary has resulted in temperatures warming through the mid-upper 80s with dewpoints in the lower 70s. Additional storms will probably develop along the trailing outflow and gradually move east-northeast with the mean wind. Considerably weaker deep-layer shear is present across the eastern part of the Corn Belt into the Lower MI vicinity compared to farther north over the U.P. of MI in closer proximity to a shortwave trough. Nonetheless, scattered thunderstorms will gradually develop within a moist/destabilizing airmass and pose a risk for isolated strong to perhaps locally severe/damaging gusts this afternoon. Farther north in WI into the U.P. of MI, a weak cold front will move into the region later this afternoon. Model guidance shows widely scattered storms developing as filtered sunshine leads to a destabilizing boundary layer. A few stronger thunderstorms are possible and could yield a localized risk for marginally severe hail and damaging gusts during the mid afternoon to early evening period. ...Southeast AZ/southwest NM... Strong heating should result in widely scattered thunderstorms developing near terrain-favored areas. Weak shear will result in disorganized storms, but the development of very steep surface to 500-mb lapse rates will promote strong evaporative cooling with the more intense downdrafts. Isolated severe gusts are possible. ..Smith/Squitieri.. 08/12/2025 Read more

SPC Aug 12, 2025 1630 UTC Day 1 Convective Outlook

1 week 6 days ago
SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1128 AM CDT Tue Aug 12 2025 Valid 121630Z - 131200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FOR PORTIONS OF THE GREAT LAKES AND SOUTHEAST ARIZONA INTO SOUTHWEST NEW MEXICO... ...SUMMARY... Strong to locally severe thunderstorms are possible over parts of the Great Lakes/Midwest this afternoon with both damaging winds and hail possible. Gusty winds may also occur over southeast Arizona and southwest New Mexico. ...Great Lakes/Midwest... Midday satellite/radar composite show a weakened thunderstorm band moving east-northeast across the eastern part of Lower MI. Surface analysis indicates rain-cooled air north of a gust front/outflow that has become draped from southeast Lower MI into the Michiana region. Heating south of this boundary has resulted in temperatures warming through the mid-upper 80s with dewpoints in the lower 70s. Additional storms will probably develop along the trailing outflow and gradually move east-northeast with the mean wind. Considerably weaker deep-layer shear is present across the eastern part of the Corn Belt into the Lower MI vicinity compared to farther north over the U.P. of MI in closer proximity to a shortwave trough. Nonetheless, scattered thunderstorms will gradually develop within a moist/destabilizing airmass and pose a risk for isolated strong to perhaps locally severe/damaging gusts this afternoon. Farther north in WI into the U.P. of MI, a weak cold front will move into the region later this afternoon. Model guidance shows widely scattered storms developing as filtered sunshine leads to a destabilizing boundary layer. A few stronger thunderstorms are possible and could yield a localized risk for marginally severe hail and damaging gusts during the mid afternoon to early evening period. ...Southeast AZ/southwest NM... Strong heating should result in widely scattered thunderstorms developing near terrain-favored areas. Weak shear will result in disorganized storms, but the development of very steep surface to 500-mb lapse rates will promote strong evaporative cooling with the more intense downdrafts. Isolated severe gusts are possible. ..Smith/Squitieri.. 08/12/2025 Read more

SPC Aug 12, 2025 1630 UTC Day 1 Convective Outlook

1 week 6 days ago
SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1128 AM CDT Tue Aug 12 2025 Valid 121630Z - 131200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FOR PORTIONS OF THE GREAT LAKES AND SOUTHEAST ARIZONA INTO SOUTHWEST NEW MEXICO... ...SUMMARY... Strong to locally severe thunderstorms are possible over parts of the Great Lakes/Midwest this afternoon with both damaging winds and hail possible. Gusty winds may also occur over southeast Arizona and southwest New Mexico. ...Great Lakes/Midwest... Midday satellite/radar composite show a weakened thunderstorm band moving east-northeast across the eastern part of Lower MI. Surface analysis indicates rain-cooled air north of a gust front/outflow that has become draped from southeast Lower MI into the Michiana region. Heating south of this boundary has resulted in temperatures warming through the mid-upper 80s with dewpoints in the lower 70s. Additional storms will probably develop along the trailing outflow and gradually move east-northeast with the mean wind. Considerably weaker deep-layer shear is present across the eastern part of the Corn Belt into the Lower MI vicinity compared to farther north over the U.P. of MI in closer proximity to a shortwave trough. Nonetheless, scattered thunderstorms will gradually develop within a moist/destabilizing airmass and pose a risk for isolated strong to perhaps locally severe/damaging gusts this afternoon. Farther north in WI into the U.P. of MI, a weak cold front will move into the region later this afternoon. Model guidance shows widely scattered storms developing as filtered sunshine leads to a destabilizing boundary layer. A few stronger thunderstorms are possible and could yield a localized risk for marginally severe hail and damaging gusts during the mid afternoon to early evening period. ...Southeast AZ/southwest NM... Strong heating should result in widely scattered thunderstorms developing near terrain-favored areas. Weak shear will result in disorganized storms, but the development of very steep surface to 500-mb lapse rates will promote strong evaporative cooling with the more intense downdrafts. Isolated severe gusts are possible. ..Smith/Squitieri.. 08/12/2025 Read more

SPC Aug 12, 2025 1630 UTC Day 1 Convective Outlook

1 week 6 days ago
SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1128 AM CDT Tue Aug 12 2025 Valid 121630Z - 131200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FOR PORTIONS OF THE GREAT LAKES AND SOUTHEAST ARIZONA INTO SOUTHWEST NEW MEXICO... ...SUMMARY... Strong to locally severe thunderstorms are possible over parts of the Great Lakes/Midwest this afternoon with both damaging winds and hail possible. Gusty winds may also occur over southeast Arizona and southwest New Mexico. ...Great Lakes/Midwest... Midday satellite/radar composite show a weakened thunderstorm band moving east-northeast across the eastern part of Lower MI. Surface analysis indicates rain-cooled air north of a gust front/outflow that has become draped from southeast Lower MI into the Michiana region. Heating south of this boundary has resulted in temperatures warming through the mid-upper 80s with dewpoints in the lower 70s. Additional storms will probably develop along the trailing outflow and gradually move east-northeast with the mean wind. Considerably weaker deep-layer shear is present across the eastern part of the Corn Belt into the Lower MI vicinity compared to farther north over the U.P. of MI in closer proximity to a shortwave trough. Nonetheless, scattered thunderstorms will gradually develop within a moist/destabilizing airmass and pose a risk for isolated strong to perhaps locally severe/damaging gusts this afternoon. Farther north in WI into the U.P. of MI, a weak cold front will move into the region later this afternoon. Model guidance shows widely scattered storms developing as filtered sunshine leads to a destabilizing boundary layer. A few stronger thunderstorms are possible and could yield a localized risk for marginally severe hail and damaging gusts during the mid afternoon to early evening period. ...Southeast AZ/southwest NM... Strong heating should result in widely scattered thunderstorms developing near terrain-favored areas. Weak shear will result in disorganized storms, but the development of very steep surface to 500-mb lapse rates will promote strong evaporative cooling with the more intense downdrafts. Isolated severe gusts are possible. ..Smith/Squitieri.. 08/12/2025 Read more

SPC Aug 12, 2025 1300 UTC Day 1 Convective Outlook

1 week 6 days ago
SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0648 AM CDT Tue Aug 12 2025 Valid 121300Z - 131200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE UPPER GREAT LAKES/MIDWEST...AND PORTIONS OF THE SOUTHWEST... ...SUMMARY... Strong to occasionally severe thunderstorms may impact parts of the upper Great Lakes/Midwest today with both damaging winds and hail possible. Gusty winds may also occur over southeast Arizona and southwest New Mexico. ...Great Lakes/Midwest... A band of thunderstorms associated with an MCV tracked northeastward across parts of IA into northern IL and southern WI early this morning while remaining mostly sub-severe. Still, there may be some potential for strong to locally damaging winds with this activity as it continues northeastward across Lake Michigan into parts of Lower MI this morning/early afternoon as daytime heating gradually destabilizes the boundary layer. Otherwise, additional convection should develop later this afternoon along/ahead of a weak front over parts of WI and the U.P. of MI as the southern portion of a mid/upper-level trough moves eastward over the Upper Midwest/Great Lakes. Instability is forecast to remain fairly modest ahead of the front, but enough deep-layer shear should exist to support some organized convection. Initial cells may be capable of producing marginally severe hail, before clustering potentially increases the threat for occasional strong to damaging winds. A separate area of thunderstorms is forecast to develop this afternoon farther south and ahead of the front from portions of the Midwest into Lower MI. While this region will have relatively weaker mid-level westerly flow and related deep-layer shear compared to locations farther north, greater low-level moisture and instability are expected to be present. As low-level lapse rates become steepened with diurnal heating of the moist airmass, loosely organized clusters may become capable of producing isolated damaging winds as they spread generally east-northeastward through the afternoon and early evening. ...Southwest... Strong daytime heating should encourage diurnally driven convection over the higher terrain of southeast AZ and southwest NM this afternoon. With weak flow aloft and negligible shear, thunderstorms should drift slowly southward. Still, occasional gusty winds may occur with the more robust convection given steepened lapse rates. ..Gleason/Leitman.. 08/12/2025 Read more

SPC Aug 12, 2025 1300 UTC Day 1 Convective Outlook

1 week 6 days ago
SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0648 AM CDT Tue Aug 12 2025 Valid 121300Z - 131200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE UPPER GREAT LAKES/MIDWEST...AND PORTIONS OF THE SOUTHWEST... ...SUMMARY... Strong to occasionally severe thunderstorms may impact parts of the upper Great Lakes/Midwest today with both damaging winds and hail possible. Gusty winds may also occur over southeast Arizona and southwest New Mexico. ...Great Lakes/Midwest... A band of thunderstorms associated with an MCV tracked northeastward across parts of IA into northern IL and southern WI early this morning while remaining mostly sub-severe. Still, there may be some potential for strong to locally damaging winds with this activity as it continues northeastward across Lake Michigan into parts of Lower MI this morning/early afternoon as daytime heating gradually destabilizes the boundary layer. Otherwise, additional convection should develop later this afternoon along/ahead of a weak front over parts of WI and the U.P. of MI as the southern portion of a mid/upper-level trough moves eastward over the Upper Midwest/Great Lakes. Instability is forecast to remain fairly modest ahead of the front, but enough deep-layer shear should exist to support some organized convection. Initial cells may be capable of producing marginally severe hail, before clustering potentially increases the threat for occasional strong to damaging winds. A separate area of thunderstorms is forecast to develop this afternoon farther south and ahead of the front from portions of the Midwest into Lower MI. While this region will have relatively weaker mid-level westerly flow and related deep-layer shear compared to locations farther north, greater low-level moisture and instability are expected to be present. As low-level lapse rates become steepened with diurnal heating of the moist airmass, loosely organized clusters may become capable of producing isolated damaging winds as they spread generally east-northeastward through the afternoon and early evening. ...Southwest... Strong daytime heating should encourage diurnally driven convection over the higher terrain of southeast AZ and southwest NM this afternoon. With weak flow aloft and negligible shear, thunderstorms should drift slowly southward. Still, occasional gusty winds may occur with the more robust convection given steepened lapse rates. ..Gleason/Leitman.. 08/12/2025 Read more

SPC Aug 12, 2025 1300 UTC Day 1 Convective Outlook

1 week 6 days ago
SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0648 AM CDT Tue Aug 12 2025 Valid 121300Z - 131200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE UPPER GREAT LAKES/MIDWEST...AND PORTIONS OF THE SOUTHWEST... ...SUMMARY... Strong to occasionally severe thunderstorms may impact parts of the upper Great Lakes/Midwest today with both damaging winds and hail possible. Gusty winds may also occur over southeast Arizona and southwest New Mexico. ...Great Lakes/Midwest... A band of thunderstorms associated with an MCV tracked northeastward across parts of IA into northern IL and southern WI early this morning while remaining mostly sub-severe. Still, there may be some potential for strong to locally damaging winds with this activity as it continues northeastward across Lake Michigan into parts of Lower MI this morning/early afternoon as daytime heating gradually destabilizes the boundary layer. Otherwise, additional convection should develop later this afternoon along/ahead of a weak front over parts of WI and the U.P. of MI as the southern portion of a mid/upper-level trough moves eastward over the Upper Midwest/Great Lakes. Instability is forecast to remain fairly modest ahead of the front, but enough deep-layer shear should exist to support some organized convection. Initial cells may be capable of producing marginally severe hail, before clustering potentially increases the threat for occasional strong to damaging winds. A separate area of thunderstorms is forecast to develop this afternoon farther south and ahead of the front from portions of the Midwest into Lower MI. While this region will have relatively weaker mid-level westerly flow and related deep-layer shear compared to locations farther north, greater low-level moisture and instability are expected to be present. As low-level lapse rates become steepened with diurnal heating of the moist airmass, loosely organized clusters may become capable of producing isolated damaging winds as they spread generally east-northeastward through the afternoon and early evening. ...Southwest... Strong daytime heating should encourage diurnally driven convection over the higher terrain of southeast AZ and southwest NM this afternoon. With weak flow aloft and negligible shear, thunderstorms should drift slowly southward. Still, occasional gusty winds may occur with the more robust convection given steepened lapse rates. ..Gleason/Leitman.. 08/12/2025 Read more

SPC Aug 12, 2025 1300 UTC Day 1 Convective Outlook

1 week 6 days ago
SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0648 AM CDT Tue Aug 12 2025 Valid 121300Z - 131200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE UPPER GREAT LAKES/MIDWEST...AND PORTIONS OF THE SOUTHWEST... ...SUMMARY... Strong to occasionally severe thunderstorms may impact parts of the upper Great Lakes/Midwest today with both damaging winds and hail possible. Gusty winds may also occur over southeast Arizona and southwest New Mexico. ...Great Lakes/Midwest... A band of thunderstorms associated with an MCV tracked northeastward across parts of IA into northern IL and southern WI early this morning while remaining mostly sub-severe. Still, there may be some potential for strong to locally damaging winds with this activity as it continues northeastward across Lake Michigan into parts of Lower MI this morning/early afternoon as daytime heating gradually destabilizes the boundary layer. Otherwise, additional convection should develop later this afternoon along/ahead of a weak front over parts of WI and the U.P. of MI as the southern portion of a mid/upper-level trough moves eastward over the Upper Midwest/Great Lakes. Instability is forecast to remain fairly modest ahead of the front, but enough deep-layer shear should exist to support some organized convection. Initial cells may be capable of producing marginally severe hail, before clustering potentially increases the threat for occasional strong to damaging winds. A separate area of thunderstorms is forecast to develop this afternoon farther south and ahead of the front from portions of the Midwest into Lower MI. While this region will have relatively weaker mid-level westerly flow and related deep-layer shear compared to locations farther north, greater low-level moisture and instability are expected to be present. As low-level lapse rates become steepened with diurnal heating of the moist airmass, loosely organized clusters may become capable of producing isolated damaging winds as they spread generally east-northeastward through the afternoon and early evening. ...Southwest... Strong daytime heating should encourage diurnally driven convection over the higher terrain of southeast AZ and southwest NM this afternoon. With weak flow aloft and negligible shear, thunderstorms should drift slowly southward. Still, occasional gusty winds may occur with the more robust convection given steepened lapse rates. ..Gleason/Leitman.. 08/12/2025 Read more

SPC Aug 12, 2025 1300 UTC Day 1 Convective Outlook

1 week 6 days ago
SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0648 AM CDT Tue Aug 12 2025 Valid 121300Z - 131200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE UPPER GREAT LAKES/MIDWEST...AND PORTIONS OF THE SOUTHWEST... ...SUMMARY... Strong to occasionally severe thunderstorms may impact parts of the upper Great Lakes/Midwest today with both damaging winds and hail possible. Gusty winds may also occur over southeast Arizona and southwest New Mexico. ...Great Lakes/Midwest... A band of thunderstorms associated with an MCV tracked northeastward across parts of IA into northern IL and southern WI early this morning while remaining mostly sub-severe. Still, there may be some potential for strong to locally damaging winds with this activity as it continues northeastward across Lake Michigan into parts of Lower MI this morning/early afternoon as daytime heating gradually destabilizes the boundary layer. Otherwise, additional convection should develop later this afternoon along/ahead of a weak front over parts of WI and the U.P. of MI as the southern portion of a mid/upper-level trough moves eastward over the Upper Midwest/Great Lakes. Instability is forecast to remain fairly modest ahead of the front, but enough deep-layer shear should exist to support some organized convection. Initial cells may be capable of producing marginally severe hail, before clustering potentially increases the threat for occasional strong to damaging winds. A separate area of thunderstorms is forecast to develop this afternoon farther south and ahead of the front from portions of the Midwest into Lower MI. While this region will have relatively weaker mid-level westerly flow and related deep-layer shear compared to locations farther north, greater low-level moisture and instability are expected to be present. As low-level lapse rates become steepened with diurnal heating of the moist airmass, loosely organized clusters may become capable of producing isolated damaging winds as they spread generally east-northeastward through the afternoon and early evening. ...Southwest... Strong daytime heating should encourage diurnally driven convection over the higher terrain of southeast AZ and southwest NM this afternoon. With weak flow aloft and negligible shear, thunderstorms should drift slowly southward. Still, occasional gusty winds may occur with the more robust convection given steepened lapse rates. ..Gleason/Leitman.. 08/12/2025 Read more

Eastern North Pacific Tropical Weather Outlook

1 week 6 days ago
000
ABPZ20 KNHC 121130
TWOEP

Tropical Weather Outlook
NWS National Hurricane Center Miami FL
500 AM PDT Tue Aug 12 2025

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

Active Systems:
The National Hurricane Center is issuing advisories on Hurricane
Henriette, located in the Central Pacific basin several hundred
miles north of the Hawaiian Islands.

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

$$
Forecaster Brown
NHC Webmaster

SPC Aug 12, 2025 Day 4-8 Severe Weather Outlook

2 weeks ago
Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0311 AM CDT Tue Aug 12 2025 Valid 151200Z - 201200Z ...DISCUSSION... From Friday/D4 into Saturday/D5, an upper low will move from Manitoba across Hudson Bay and into Quebec. Moderate midlevel westerlies will exist over the far northern Plains to Upper Great Lakes during this period, with gradual weakening. An upper high will also be centered over the mid MS Valley, while a weak midlevel trough with cool air aloft slowly departs the Great Basin. At the surface, a front is forecast to stall on Friday/D4 from northern NE across southern MN and into northern WI, with a moist and unstable air mass remaining to the south. This front will remain over roughly the same zone into Saturday/D5, and perhaps as late as Sunday/D6. Given that the moist and unstable air mass will persist over parts of the northern Plains/Upper MS Valley, and minor ripples in the flow are hinted at by several models, areas of storms are expected. However, storm/MCS corridors are difficult to pinpoint this far out. In general, the area from SD into WI will bear watching for wind potential. From Sunday/D6 onward, an upper ridge is expected to build over much of the western and central states, with a reduction in severe potential overall. Read more

SPC Aug 12, 2025 Day 4-8 Severe Weather Outlook

2 weeks ago
Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0311 AM CDT Tue Aug 12 2025 Valid 151200Z - 201200Z ...DISCUSSION... From Friday/D4 into Saturday/D5, an upper low will move from Manitoba across Hudson Bay and into Quebec. Moderate midlevel westerlies will exist over the far northern Plains to Upper Great Lakes during this period, with gradual weakening. An upper high will also be centered over the mid MS Valley, while a weak midlevel trough with cool air aloft slowly departs the Great Basin. At the surface, a front is forecast to stall on Friday/D4 from northern NE across southern MN and into northern WI, with a moist and unstable air mass remaining to the south. This front will remain over roughly the same zone into Saturday/D5, and perhaps as late as Sunday/D6. Given that the moist and unstable air mass will persist over parts of the northern Plains/Upper MS Valley, and minor ripples in the flow are hinted at by several models, areas of storms are expected. However, storm/MCS corridors are difficult to pinpoint this far out. In general, the area from SD into WI will bear watching for wind potential. From Sunday/D6 onward, an upper ridge is expected to build over much of the western and central states, with a reduction in severe potential overall. Read more

SPC Aug 12, 2025 Day 4-8 Severe Weather Outlook

2 weeks ago
Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0311 AM CDT Tue Aug 12 2025 Valid 151200Z - 201200Z ...DISCUSSION... From Friday/D4 into Saturday/D5, an upper low will move from Manitoba across Hudson Bay and into Quebec. Moderate midlevel westerlies will exist over the far northern Plains to Upper Great Lakes during this period, with gradual weakening. An upper high will also be centered over the mid MS Valley, while a weak midlevel trough with cool air aloft slowly departs the Great Basin. At the surface, a front is forecast to stall on Friday/D4 from northern NE across southern MN and into northern WI, with a moist and unstable air mass remaining to the south. This front will remain over roughly the same zone into Saturday/D5, and perhaps as late as Sunday/D6. Given that the moist and unstable air mass will persist over parts of the northern Plains/Upper MS Valley, and minor ripples in the flow are hinted at by several models, areas of storms are expected. However, storm/MCS corridors are difficult to pinpoint this far out. In general, the area from SD into WI will bear watching for wind potential. From Sunday/D6 onward, an upper ridge is expected to build over much of the western and central states, with a reduction in severe potential overall. Read more

SPC Aug 12, 2025 Day 4-8 Severe Weather Outlook

2 weeks ago
Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0311 AM CDT Tue Aug 12 2025 Valid 151200Z - 201200Z ...DISCUSSION... From Friday/D4 into Saturday/D5, an upper low will move from Manitoba across Hudson Bay and into Quebec. Moderate midlevel westerlies will exist over the far northern Plains to Upper Great Lakes during this period, with gradual weakening. An upper high will also be centered over the mid MS Valley, while a weak midlevel trough with cool air aloft slowly departs the Great Basin. At the surface, a front is forecast to stall on Friday/D4 from northern NE across southern MN and into northern WI, with a moist and unstable air mass remaining to the south. This front will remain over roughly the same zone into Saturday/D5, and perhaps as late as Sunday/D6. Given that the moist and unstable air mass will persist over parts of the northern Plains/Upper MS Valley, and minor ripples in the flow are hinted at by several models, areas of storms are expected. However, storm/MCS corridors are difficult to pinpoint this far out. In general, the area from SD into WI will bear watching for wind potential. From Sunday/D6 onward, an upper ridge is expected to build over much of the western and central states, with a reduction in severe potential overall. Read more