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Issued at 300 AM MDT Thu Aug 22 2019 000 WTPZ45 KNHC 220842 TCDEP5 Tropical Storm Ivo Discussion Number 4 NWS National Hurricane Center Miami FL EP102019 300 AM MDT Thu Aug 22 2019 The cloud pattern associated with Ivo is a little better organized and consists of a circular mass of convection surrounded by a well- defined cyclonically curved band. The center appears to be more embedded under the canopy than several hours ago. Despite the improvement, recent scatterometer data show that the winds have not increased yet and are between 40 and 45 kt. Because the cloud pattern has improved since then, the initial intensity has been increased to 50 kt, which is the consensus among TAFB, SAB and SATCON estimates. The environment during the next 36 hours should favor Ivo to strengthen a little more and reach hurricane status. Thereafter, Ivo should begin to encounter dry air and cooler waters, resulting in gradual weakening. By day 4, Ivo should be over 20 degree Celsius waters and become a remnant low void of deep convection. The intensity forecast follows very closely the HCCA solution and is a little higher than the consensus. Satellite data suggest that the center of Ivo has either moved a little bit south of due west or it has reformed closer to the convection with a decrease in forward speed. However, an average of the past 6 to 12 hours gives a motion toward the west or 270 degrees at 11 kt. Ivo should be reaching the southwestern edge of a subtropical ridge in 12 to 24 hours, and this flow pattern should steer the cyclone more toward the west-northwest and northwest. This general motion should then continue until the end of the forecast period. The NHC forecast is a little to the right of the previous one, but it is still on the western edge of the guidance envelope and in between the HFIP corrected consensus HCCA and the multi-model average TVCE. FORECAST POSITIONS AND MAX WINDS INIT 22/0900Z 15.8N 112.5W 50 KT 60 MPH 12H 22/1800Z 16.2N 114.1W 55 KT 65 MPH 24H 23/0600Z 17.4N 115.3W 60 KT 70 MPH 36H 23/1800Z 19.0N 116.3W 65 KT 75 MPH 48H 24/0600Z 20.7N 117.1W 55 KT 65 MPH 72H 25/0600Z 24.6N 119.2W 35 KT 40 MPH 96H 26/0600Z 28.0N 121.5W 30 KT 35 MPH...POST-TROP/REMNT LOW 120H 27/0600Z 30.5N 123.5W 25 KT 30 MPH...POST-TROP/REMNT LOW $$ Forecaster Avila

Issued at 300 AM MDT Thu Aug 22 2019 000 WTPZ35 KNHC 220841 TCPEP5 BULLETIN Tropical Storm Ivo Advisory Number 4 NWS National Hurricane Center Miami FL EP102019 300 AM MDT Thu Aug 22 2019 ...IVO FORECAST TO BECOME A HURRICANE IN A DAY OR SO OVER OPEN WATERS... SUMMARY OF 300 AM MDT...0900 UTC...INFORMATION ---------------------------------------------- LOCATION...15.8N 112.5W ABOUT 520 MI...835 KM SSW OF THE SOUTHERN TIP OF BAJA CALIFORNIA MAXIMUM SUSTAINED WINDS...60 MPH...95 KM/H PRESENT MOVEMENT...W OR 270 DEGREES AT 13 MPH...20 KM/H MINIMUM CENTRAL PRESSURE...998 MB...29.47 INCHES WATCHES AND WARNINGS -------------------- There are no coastal watches or warnings in effect. DISCUSSION AND OUTLOOK ---------------------- At 300 AM MDT (0900 UTC), the center of Tropical Storm Ivo was located near latitude 15.8 North, longitude 112.5 West. Ivo has decreased its forward speed and is moving toward the west near 13 mph (20 km/h). A turn toward the west-northwest is expected later today or Friday with a northwestward motion continuing thereafter. Maximum sustained winds are near 60 mph (95 km/h) with higher gusts. Ivo is forecast to become a hurricane by Friday, but weakening should then begin after that time. Tropical-storm-force winds extend outward up to 45 miles (75 km) from the center. The estimated minimum central pressure is 998 mb (29.47 inches). HAZARDS AFFECTING LAND ---------------------- None NEXT ADVISORY ------------- Next complete advisory at 900 AM MDT. $$ Forecaster Avila

...IVO FORECAST TO BECOME A HURRICANE IN A DAY OR SO OVER OPEN WATERS... As of 3:00 AM MDT Thu Aug 22 the center of Ivo was located near 15.8, -112.5 with movement W at 13 mph. The minimum central pressure was 998 mb with maximum sustained winds of about 60 mph.

Issued at 0900 UTC THU AUG 22 2019 000 WTPZ25 KNHC 220841 TCMEP5 TROPICAL STORM IVO FORECAST/ADVISORY NUMBER 4 NWS NATIONAL HURRICANE CENTER MIAMI FL EP102019 0900 UTC THU AUG 22 2019 THERE ARE NO COASTAL WATCHES OR WARNINGS IN EFFECT. TROPICAL STORM CENTER LOCATED NEAR 15.8N 112.5W AT 22/0900Z POSITION ACCURATE WITHIN 25 NM PRESENT MOVEMENT TOWARD THE WEST OR 270 DEGREES AT 11 KT ESTIMATED MINIMUM CENTRAL PRESSURE 998 MB MAX SUSTAINED WINDS 50 KT WITH GUSTS TO 60 KT. 50 KT....... 20NE 20SE 0SW 0NW. 34 KT....... 40NE 30SE 10SW 30NW. 12 FT SEAS.. 90NE 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 15.8N 112.5W AT 22/0900Z AT 22/0600Z CENTER WAS LOCATED NEAR 15.7N 112.0W FORECAST VALID 22/1800Z 16.2N 114.1W MAX WIND 55 KT...GUSTS 65 KT. 50 KT... 20NE 0SE 0SW 20NW. 34 KT... 50NE 40SE 30SW 50NW. FORECAST VALID 23/0600Z 17.4N 115.3W MAX WIND 60 KT...GUSTS 75 KT. 50 KT... 30NE 30SE 20SW 30NW. 34 KT... 60NE 60SE 40SW 60NW. FORECAST VALID 23/1800Z 19.0N 116.3W MAX WIND 65 KT...GUSTS 80 KT. 64 KT... 20NE 20SE 0SW 15NW. 50 KT... 40NE 40SE 20SW 30NW. 34 KT... 80NE 80SE 60SW 70NW. FORECAST VALID 24/0600Z 20.7N 117.1W MAX WIND 55 KT...GUSTS 65 KT. 50 KT... 40NE 40SE 20SW 30NW. 34 KT... 80NE 80SE 60SW 70NW. FORECAST VALID 25/0600Z 24.6N 119.2W MAX WIND 35 KT...GUSTS 45 KT. 34 KT... 70NE 70SE 50SW 60NW. EXTENDED OUTLOOK. NOTE...ERRORS FOR TRACK HAVE AVERAGED NEAR 100 NM ON DAY 4 AND 150 NM ON DAY 5...AND FOR INTENSITY NEAR 15 KT EACH DAY OUTLOOK VALID 26/0600Z 28.0N 121.5W...POST-TROP/REMNT LOW MAX WIND 30 KT...GUSTS 40 KT. OUTLOOK VALID 27/0600Z 30.5N 123.5W...POST-TROP/REMNT LOW MAX WIND 25 KT...GUSTS 35 KT. REQUEST FOR 3 HOURLY SHIP REPORTS WITHIN 300 MILES OF 15.8N 112.5W NEXT ADVISORY AT 22/1500Z $$ FORECASTER AVILA

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook CORR 1 NWS Storm Prediction Center Norman OK 0157 AM CDT Thu Aug 22 2019 Valid 221200Z - 231200Z CORRECTED FOR TEXT ...CRITICAL FIRE WEATHER AREA FOR PORTIONS OF UTAH...NORTHERN ARIZONA...SOUTHEAST NEVADA...SOUTHWEST WYOMING...NORTHWEST COLORADO... ...Synopsis... An upper-level shortwave trough will continue moving eastward over the Pacific Northwest and northern Rockies today. An associated surface cold front will also continue pushing east and south through much of the northern Rockies and northern California and into the Great Basin. A pre-frontal surface pressure trough will run parallel to the cold front stretching southwest from north-central Montana into southern Nevada. A broad area of elevated conditions will develop stretching from northern Arizona/southern Nevada into central Wyoming, with critical conditions likely developing in far northwest Arizona/southeast Nevada through central Utah into southwest Wyoming. West-southwest sustained surface winds of 15-25 mph with RH values of 8-20% are likely to develop ahead of the cold front during the afternoon and into the evening. ERCs are mostly above the 80th percentile within the elevated/critical areas including some locations above the 95th percentile. Elevated conditions are likely across portions of the Snake River Plain and vicinity this afternoon. The cold front will likely push through the area this morning. However, daytime heating will help mix/deepen the boundary layer and increase surface temperatures with west-southwest surface winds of 15-20 mph and RH values of 15-20% developing during the afternoon. ..Nauslar.. 08/22/2019 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook CORR 1 NWS Storm Prediction Center Norman OK 0157 AM CDT Thu Aug 22 2019 Valid 221200Z - 231200Z CORRECTED FOR TEXT ...CRITICAL FIRE WEATHER AREA FOR PORTIONS OF UTAH...NORTHERN ARIZONA...SOUTHEAST NEVADA...SOUTHWEST WYOMING...NORTHWEST COLORADO... ...Synopsis... An upper-level shortwave trough will continue moving eastward over the Pacific Northwest and northern Rockies today. An associated surface cold front will also continue pushing east and south through much of the northern Rockies and northern California and into the Great Basin. A pre-frontal surface pressure trough will run parallel to the cold front stretching southwest from north-central Montana into southern Nevada. A broad area of elevated conditions will develop stretching from northern Arizona/southern Nevada into central Wyoming, with critical conditions likely developing in far northwest Arizona/southeast Nevada through central Utah into southwest Wyoming. West-southwest sustained surface winds of 15-25 mph with RH values of 8-20% are likely to develop ahead of the cold front during the afternoon and into the evening. ERCs are mostly above the 80th percentile within the elevated/critical areas including some locations above the 95th percentile. Elevated conditions are likely across portions of the Snake River Plain and vicinity this afternoon. The cold front will likely push through the area this morning. However, daytime heating will help mix/deepen the boundary layer and increase surface temperatures with west-southwest surface winds of 15-20 mph and RH values of 15-20% developing during the afternoon. ..Nauslar.. 08/22/2019 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook CORR 1 NWS Storm Prediction Center Norman OK 0157 AM CDT Thu Aug 22 2019 Valid 221200Z - 231200Z CORRECTED FOR TEXT ...CRITICAL FIRE WEATHER AREA FOR PORTIONS OF UTAH...NORTHERN ARIZONA...SOUTHEAST NEVADA...SOUTHWEST WYOMING...NORTHWEST COLORADO... ...Synopsis... An upper-level shortwave trough will continue moving eastward over the Pacific Northwest and northern Rockies today. An associated surface cold front will also continue pushing east and south through much of the northern Rockies and northern California and into the Great Basin. A pre-frontal surface pressure trough will run parallel to the cold front stretching southwest from north-central Montana into southern Nevada. A broad area of elevated conditions will develop stretching from northern Arizona/southern Nevada into central Wyoming, with critical conditions likely developing in far northwest Arizona/southeast Nevada through central Utah into southwest Wyoming. West-southwest sustained surface winds of 15-25 mph with RH values of 8-20% are likely to develop ahead of the cold front during the afternoon and into the evening. ERCs are mostly above the 80th percentile within the elevated/critical areas including some locations above the 95th percentile. Elevated conditions are likely across portions of the Snake River Plain and vicinity this afternoon. The cold front will likely push through the area this morning. However, daytime heating will help mix/deepen the boundary layer and increase surface temperatures with west-southwest surface winds of 15-20 mph and RH values of 15-20% developing during the afternoon. ..Nauslar.. 08/22/2019 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0146 AM CDT Thu Aug 22 2019 Valid 241200Z - 251200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS OVER THE NORTHERN PLAINS... ...SUMMARY... At least isolated severe storms are possible over parts of the northern Plains Saturday. ...Synopsis... Strong cyclonic flow aloft will develop southeastward into the northern Rockies, providing increased deep-layer shear and cooling aloft to the northern High Plains. A weak shortwave trough will precede this larger-scale wave, aiding lift over the Dakotas and MN during the day. At the surface, low pressure will deepen over the northern High Plains, enhancing southerly surface winds and maintaining a plume of 60s F dewpoints from KS to southern Manitoba. Convergence along a cold front will increase overnight and into Sunday morning from eastern MT toward the Black Hills, providing lift. Elsewhere, a moist and unstable air mass will remain over the southern Plains and lower MS Valley, with various areas of storms and outflow boundaries throughout the period. Any potential marginal threat area here for wind gusts is currently unpredictable. ...Northern Plains... Storms are likely to be ongoing across the central Dakotas, and possibly into north-central NE Saturday morning, near the eastern instability gradient where southwesterly 850 mb winds of 30-40 kt will provide lift via warm advection. Marginal hail cannot be ruled out early. Later in the day, heating will remove CIN over the central and western Dakotas, and redevelopment is possible near the tail end of the departing lead wave over ND. Veering winds with height will favor a supercell or two, with severe threat dependent on how much instability can develop near an axis of 200-300 m2/s2 effective SRH. Isolated cells are also possible at peak heating over western SD. Overnight, large-scale lift will increase from MT into the western Dakotas. Steep lapse rates aloft and strengthening deep-layer shear will conditionally favor severe storms, however, it is unclear how much moisture and instability will exist overnight that far west. Parts of the area may require a categorical upgrade in future outlooks should instability increase. ..Jewell.. 08/22/2019 Read more

SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0146 AM CDT Thu Aug 22 2019 Valid 241200Z - 251200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS OVER THE NORTHERN PLAINS... ...SUMMARY... At least isolated severe storms are possible over parts of the northern Plains Saturday. ...Synopsis... Strong cyclonic flow aloft will develop southeastward into the northern Rockies, providing increased deep-layer shear and cooling aloft to the northern High Plains. A weak shortwave trough will precede this larger-scale wave, aiding lift over the Dakotas and MN during the day. At the surface, low pressure will deepen over the northern High Plains, enhancing southerly surface winds and maintaining a plume of 60s F dewpoints from KS to southern Manitoba. Convergence along a cold front will increase overnight and into Sunday morning from eastern MT toward the Black Hills, providing lift. Elsewhere, a moist and unstable air mass will remain over the southern Plains and lower MS Valley, with various areas of storms and outflow boundaries throughout the period. Any potential marginal threat area here for wind gusts is currently unpredictable. ...Northern Plains... Storms are likely to be ongoing across the central Dakotas, and possibly into north-central NE Saturday morning, near the eastern instability gradient where southwesterly 850 mb winds of 30-40 kt will provide lift via warm advection. Marginal hail cannot be ruled out early. Later in the day, heating will remove CIN over the central and western Dakotas, and redevelopment is possible near the tail end of the departing lead wave over ND. Veering winds with height will favor a supercell or two, with severe threat dependent on how much instability can develop near an axis of 200-300 m2/s2 effective SRH. Isolated cells are also possible at peak heating over western SD. Overnight, large-scale lift will increase from MT into the western Dakotas. Steep lapse rates aloft and strengthening deep-layer shear will conditionally favor severe storms, however, it is unclear how much moisture and instability will exist overnight that far west. Parts of the area may require a categorical upgrade in future outlooks should instability increase. ..Jewell.. 08/22/2019 Read more

SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0146 AM CDT Thu Aug 22 2019 Valid 241200Z - 251200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS OVER THE NORTHERN PLAINS... ...SUMMARY... At least isolated severe storms are possible over parts of the northern Plains Saturday. ...Synopsis... Strong cyclonic flow aloft will develop southeastward into the northern Rockies, providing increased deep-layer shear and cooling aloft to the northern High Plains. A weak shortwave trough will precede this larger-scale wave, aiding lift over the Dakotas and MN during the day. At the surface, low pressure will deepen over the northern High Plains, enhancing southerly surface winds and maintaining a plume of 60s F dewpoints from KS to southern Manitoba. Convergence along a cold front will increase overnight and into Sunday morning from eastern MT toward the Black Hills, providing lift. Elsewhere, a moist and unstable air mass will remain over the southern Plains and lower MS Valley, with various areas of storms and outflow boundaries throughout the period. Any potential marginal threat area here for wind gusts is currently unpredictable. ...Northern Plains... Storms are likely to be ongoing across the central Dakotas, and possibly into north-central NE Saturday morning, near the eastern instability gradient where southwesterly 850 mb winds of 30-40 kt will provide lift via warm advection. Marginal hail cannot be ruled out early. Later in the day, heating will remove CIN over the central and western Dakotas, and redevelopment is possible near the tail end of the departing lead wave over ND. Veering winds with height will favor a supercell or two, with severe threat dependent on how much instability can develop near an axis of 200-300 m2/s2 effective SRH. Isolated cells are also possible at peak heating over western SD. Overnight, large-scale lift will increase from MT into the western Dakotas. Steep lapse rates aloft and strengthening deep-layer shear will conditionally favor severe storms, however, it is unclear how much moisture and instability will exist overnight that far west. Parts of the area may require a categorical upgrade in future outlooks should instability increase. ..Jewell.. 08/22/2019 Read more

5-Day Uncertainty Track last updated Thu, 22 Aug 2019 06:42:10 GMT


Wind Speed Probabilities last updated Thu, 22 Aug 2019 06:42:11 GMT

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0133 AM CDT Thu Aug 22 2019 Valid 231200Z - 241200Z ...NO CRITICAL AREAS... ...Synopsis... The upper-level shortwave trough that tracked over the Pacific Northwest and northern Rockies during the past couple of days will begin to weaken while slowly lifting east-northeast across the northern Plains. A stronger upper-level trough will approach the Pacific Northwest tomorrow with a westerly mid-level jet (35-50 knots) preceding it and stretching across the Pacific Northwest and northern Rockies. The south/east progress of the surface cold front will slow with it likely becoming a stationary front across northern Utah and central Nevada. Elevated conditions may develop across portions of southwest Wyoming into northwest Colorado, but they should be confined to vegetation-sparse areas. Elevated conditions may also develop across portions southern Utah and northern Arizona. However, a weakening surface pressure gradient, lack of mid-level flow, and the possibility of high clouds moving northward preclude an elevated area at this time. ..Nauslar.. 08/22/2019 ...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 0133 AM CDT Thu Aug 22 2019 Valid 231200Z - 241200Z ...NO CRITICAL AREAS... ...Synopsis... The upper-level shortwave trough that tracked over the Pacific Northwest and northern Rockies during the past couple of days will begin to weaken while slowly lifting east-northeast across the northern Plains. A stronger upper-level trough will approach the Pacific Northwest tomorrow with a westerly mid-level jet (35-50 knots) preceding it and stretching across the Pacific Northwest and northern Rockies. The south/east progress of the surface cold front will slow with it likely becoming a stationary front across northern Utah and central Nevada. Elevated conditions may develop across portions of southwest Wyoming into northwest Colorado, but they should be confined to vegetation-sparse areas. Elevated conditions may also develop across portions southern Utah and northern Arizona. However, a weakening surface pressure gradient, lack of mid-level flow, and the possibility of high clouds moving northward preclude an elevated area at this time. ..Nauslar.. 08/22/2019 ...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 0133 AM CDT Thu Aug 22 2019 Valid 231200Z - 241200Z ...NO CRITICAL AREAS... ...Synopsis... The upper-level shortwave trough that tracked over the Pacific Northwest and northern Rockies during the past couple of days will begin to weaken while slowly lifting east-northeast across the northern Plains. A stronger upper-level trough will approach the Pacific Northwest tomorrow with a westerly mid-level jet (35-50 knots) preceding it and stretching across the Pacific Northwest and northern Rockies. The south/east progress of the surface cold front will slow with it likely becoming a stationary front across northern Utah and central Nevada. Elevated conditions may develop across portions of southwest Wyoming into northwest Colorado, but they should be confined to vegetation-sparse areas. Elevated conditions may also develop across portions southern Utah and northern Arizona. However, a weakening surface pressure gradient, lack of mid-level flow, and the possibility of high clouds moving northward preclude an elevated area at this time. ..Nauslar.. 08/22/2019 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1201 AM CDT Thu Aug 22 2019 Valid 231200Z - 241200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM SOUTHERN VIRGINIA INTO NORTH CAROLINA...AND OVER THE NORTHERN AND CENTRAL HIGH PLAINS... ...SUMMARY... Isolated severe wind gusts are possible Friday over parts of North Carolina and southern Virginia, with hail and localized strong gusts possible over the northern and central High Plains. ...Synopsis... A positive-tilt upper trough will move across the Northeast with around 30 kt midlevel winds trailing across the Mid Atlantic. A front will drift southward across VA during the day, providing lift for storms, some capable of wind damage, from VA into NC. The westward extension of this front will move into Plains, with southeast surface winds maintaining 60s F dewpoints into the High Plains. A compact shortwave trough will move from WY into the Dakotas, providing cool air aloft and maximizing instability for a few strong to severe storms capable of hail. ...Southern VA into NC... Areas of thunderstorms may be ongoing Friday morning from eastern KY across WV and into western VA in association with lift near the right entrance region of the upper jet. Preceding this activity, heating of a moist air mass will lead to around 2000 J/kg MLCAPE, allowing ongoing activity to strengthen during the day. New development is also likely eastward along the front. While this boundary will be parallel to the upper flow, a southeastward propagation is expected as storms merge outflows, with locally damaging winds possible in an otherwise weak shear environment. ...Northern and central High Plains... Temperatures aloft will become cool for this time of year with the weak upper trough. Shear will not increase much, but southeast low-level winds will maintain ample moisture into eastern WY and CO, with isolated strong storms likely by late afternoon forming near the Front Range. Additional storms are likely over the Black Hills. Storms are generally expected to move east, within a narrow north-south corridor of hail or marginal wind threat with capping to the east. ...MAXIMUM RISK BY HAZARD... Tornado: 2% - Marginal Wind: 5% - Marginal Hail: 5% - Marginal ..Jewell.. 08/22/2019 Read more

SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1201 AM CDT Thu Aug 22 2019 Valid 231200Z - 241200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM SOUTHERN VIRGINIA INTO NORTH CAROLINA...AND OVER THE NORTHERN AND CENTRAL HIGH PLAINS... ...SUMMARY... Isolated severe wind gusts are possible Friday over parts of North Carolina and southern Virginia, with hail and localized strong gusts possible over the northern and central High Plains. ...Synopsis... A positive-tilt upper trough will move across the Northeast with around 30 kt midlevel winds trailing across the Mid Atlantic. A front will drift southward across VA during the day, providing lift for storms, some capable of wind damage, from VA into NC. The westward extension of this front will move into Plains, with southeast surface winds maintaining 60s F dewpoints into the High Plains. A compact shortwave trough will move from WY into the Dakotas, providing cool air aloft and maximizing instability for a few strong to severe storms capable of hail. ...Southern VA into NC... Areas of thunderstorms may be ongoing Friday morning from eastern KY across WV and into western VA in association with lift near the right entrance region of the upper jet. Preceding this activity, heating of a moist air mass will lead to around 2000 J/kg MLCAPE, allowing ongoing activity to strengthen during the day. New development is also likely eastward along the front. While this boundary will be parallel to the upper flow, a southeastward propagation is expected as storms merge outflows, with locally damaging winds possible in an otherwise weak shear environment. ...Northern and central High Plains... Temperatures aloft will become cool for this time of year with the weak upper trough. Shear will not increase much, but southeast low-level winds will maintain ample moisture into eastern WY and CO, with isolated strong storms likely by late afternoon forming near the Front Range. Additional storms are likely over the Black Hills. Storms are generally expected to move east, within a narrow north-south corridor of hail or marginal wind threat with capping to the east. ...MAXIMUM RISK BY HAZARD... Tornado: 2% - Marginal Wind: 5% - Marginal Hail: 5% - Marginal ..Jewell.. 08/22/2019 Read more

SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1201 AM CDT Thu Aug 22 2019 Valid 231200Z - 241200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM SOUTHERN VIRGINIA INTO NORTH CAROLINA...AND OVER THE NORTHERN AND CENTRAL HIGH PLAINS... ...SUMMARY... Isolated severe wind gusts are possible Friday over parts of North Carolina and southern Virginia, with hail and localized strong gusts possible over the northern and central High Plains. ...Synopsis... A positive-tilt upper trough will move across the Northeast with around 30 kt midlevel winds trailing across the Mid Atlantic. A front will drift southward across VA during the day, providing lift for storms, some capable of wind damage, from VA into NC. The westward extension of this front will move into Plains, with southeast surface winds maintaining 60s F dewpoints into the High Plains. A compact shortwave trough will move from WY into the Dakotas, providing cool air aloft and maximizing instability for a few strong to severe storms capable of hail. ...Southern VA into NC... Areas of thunderstorms may be ongoing Friday morning from eastern KY across WV and into western VA in association with lift near the right entrance region of the upper jet. Preceding this activity, heating of a moist air mass will lead to around 2000 J/kg MLCAPE, allowing ongoing activity to strengthen during the day. New development is also likely eastward along the front. While this boundary will be parallel to the upper flow, a southeastward propagation is expected as storms merge outflows, with locally damaging winds possible in an otherwise weak shear environment. ...Northern and central High Plains... Temperatures aloft will become cool for this time of year with the weak upper trough. Shear will not increase much, but southeast low-level winds will maintain ample moisture into eastern WY and CO, with isolated strong storms likely by late afternoon forming near the Front Range. Additional storms are likely over the Black Hills. Storms are generally expected to move east, within a narrow north-south corridor of hail or marginal wind threat with capping to the east. ...MAXIMUM RISK BY HAZARD... Tornado: 2% - Marginal Wind: 5% - Marginal Hail: 5% - Marginal ..Jewell.. 08/22/2019 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1245 AM CDT Thu Aug 22 2019 Valid 221200Z - 231200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE NORTHERN AND CENTRAL HIGH PLAINS AND FROM OK INTO THE MID-ATLANTIC AND NEW ENGLAND... ...SUMMARY... Isolated severe wind gusts are possible this afternoon and evening from Oklahoma eastward across the Ohio Valley and into parts of the mid-Atlantic and New England. Meanwhile, hail or wind, occasionally reaching severe levels, will also be possible over the central and northern High Plains area. ...Synopsis... A couple of upper level troughs and associated surface cold fronts will result in a few areas of strong, occasionally severe storms today. The first trough will pivot eastward from the upper Great Lakes to the Northeast. A band of stronger southwesterly deep-layer flow will overspread much of the northeastern U.S. from around PA northward while a surface cold front shifts eastward. The western extent of the front will drop more slowly south/southeast across the Midwest, extending from southern MO toward Chesapeake Bay by Friday morning. Several weak shortwave impulses and remnant MCVs will float through westerly flow from OK to the Mid-Atlantic ahead of the southward-sagging front, aiding in the development of sporadically strong thunderstorm clusters. Further northwest, a shortwave trough will migrate eastward across the northern Rockies. A surface cold front will progress eastward across MT/WY during the afternoon and evening, while a surface trough strengthens southeasterly low level flow in a moist upslope flow regime across the northern High Plains. This will focus another area for strong storm potential during the afternoon and evening across parts of the northern and central High Plains. ...Mid-Atlantic and New England... A warm and very moist airmass will reside ahead of the surface cold front. Overall, west/southwesterly flow will be rather modest, with the strongest flow residing over the Northeast. A corridor of modest destabilization will overlap with this relatively stronger flow, and a few fast moving storm clusters or line segments are possible from PA northward through coastal ME. A few strong wind gusts could accompany this activity, though the overall threat should remain limited by poor midlevel lapse rates and in the absence of stronger shear. Further south toward the Chesapeake and VA/NC Piedmont vicinity, thunderstorm clusters are expected to develop in vicinity of a lee trough as subtle shortwave impulses migrate across the Appalachians. The airmass across this area will be very moist with PW values greater than 2 inches forecast. Strong heating will result in moderate destabilization and some strong gusts in wet microbursts will be possible. ...Oklahoma toward the Ohio Valley... Deep-layer westerly flow will remain weak across the region. However, several shortwave impulses are forecast to migrate through westerly flow while a myriad of outflow boundaries and MCVs from prior convection influence thunderstorm development during the afternoon. Steep lapse rates and moderate instability will be sufficient for severe storms, but weak flow will limit overall organization. Nevertheless a few strong to severe storms are possible with strong downburst winds being the main threat. Should an adequate cold pool develop, very steep low level lapse rates could support a surging cluster/bow with an increased threat for damaging wind, but confidence in this scenario is low, precluding higher probabilities. ...Portions of the Northern/Central High Plains... Strong southeasterly upslope flow in the vicinity of a pre-frontal lee trough will bring upper 50s to low 60s surface dewpoints across the High Plains of MT/WY/CO. Strong heating and very steep midlevel lapse rates will result in 2000-3000 J/kg MLCAPE by afternoon. While southeast flow through around 2 km will be strong, mid and upper-level flow will remain rather weak. Nevertheless, as forcing increases with the approach of a surface cold front and the upper trough, scattered thunderstorms are expected. A deeply mixed sub-cloud layer will support strong downburst winds, especially as clusters/line segments are favored. However, very steep midlevel lapse rates also will support some potential for hail initially. In the absence of stronger shear, will maintain Marginal risk. Further west across the higher terrain of south-central into southwest MT, a couple of storms could produce gusty winds and hail as the cold front moves through during the early afternoon. ..Leitman.. 08/22/2019 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1245 AM CDT Thu Aug 22 2019 Valid 221200Z - 231200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE NORTHERN AND CENTRAL HIGH PLAINS AND FROM OK INTO THE MID-ATLANTIC AND NEW ENGLAND... ...SUMMARY... Isolated severe wind gusts are possible this afternoon and evening from Oklahoma eastward across the Ohio Valley and into parts of the mid-Atlantic and New England. Meanwhile, hail or wind, occasionally reaching severe levels, will also be possible over the central and northern High Plains area. ...Synopsis... A couple of upper level troughs and associated surface cold fronts will result in a few areas of strong, occasionally severe storms today. The first trough will pivot eastward from the upper Great Lakes to the Northeast. A band of stronger southwesterly deep-layer flow will overspread much of the northeastern U.S. from around PA northward while a surface cold front shifts eastward. The western extent of the front will drop more slowly south/southeast across the Midwest, extending from southern MO toward Chesapeake Bay by Friday morning. Several weak shortwave impulses and remnant MCVs will float through westerly flow from OK to the Mid-Atlantic ahead of the southward-sagging front, aiding in the development of sporadically strong thunderstorm clusters. Further northwest, a shortwave trough will migrate eastward across the northern Rockies. A surface cold front will progress eastward across MT/WY during the afternoon and evening, while a surface trough strengthens southeasterly low level flow in a moist upslope flow regime across the northern High Plains. This will focus another area for strong storm potential during the afternoon and evening across parts of the northern and central High Plains. ...Mid-Atlantic and New England... A warm and very moist airmass will reside ahead of the surface cold front. Overall, west/southwesterly flow will be rather modest, with the strongest flow residing over the Northeast. A corridor of modest destabilization will overlap with this relatively stronger flow, and a few fast moving storm clusters or line segments are possible from PA northward through coastal ME. A few strong wind gusts could accompany this activity, though the overall threat should remain limited by poor midlevel lapse rates and in the absence of stronger shear. Further south toward the Chesapeake and VA/NC Piedmont vicinity, thunderstorm clusters are expected to develop in vicinity of a lee trough as subtle shortwave impulses migrate across the Appalachians. The airmass across this area will be very moist with PW values greater than 2 inches forecast. Strong heating will result in moderate destabilization and some strong gusts in wet microbursts will be possible. ...Oklahoma toward the Ohio Valley... Deep-layer westerly flow will remain weak across the region. However, several shortwave impulses are forecast to migrate through westerly flow while a myriad of outflow boundaries and MCVs from prior convection influence thunderstorm development during the afternoon. Steep lapse rates and moderate instability will be sufficient for severe storms, but weak flow will limit overall organization. Nevertheless a few strong to severe storms are possible with strong downburst winds being the main threat. Should an adequate cold pool develop, very steep low level lapse rates could support a surging cluster/bow with an increased threat for damaging wind, but confidence in this scenario is low, precluding higher probabilities. ...Portions of the Northern/Central High Plains... Strong southeasterly upslope flow in the vicinity of a pre-frontal lee trough will bring upper 50s to low 60s surface dewpoints across the High Plains of MT/WY/CO. Strong heating and very steep midlevel lapse rates will result in 2000-3000 J/kg MLCAPE by afternoon. While southeast flow through around 2 km will be strong, mid and upper-level flow will remain rather weak. Nevertheless, as forcing increases with the approach of a surface cold front and the upper trough, scattered thunderstorms are expected. A deeply mixed sub-cloud layer will support strong downburst winds, especially as clusters/line segments are favored. However, very steep midlevel lapse rates also will support some potential for hail initially. In the absence of stronger shear, will maintain Marginal risk. Further west across the higher terrain of south-central into southwest MT, a couple of storms could produce gusty winds and hail as the cold front moves through during the early afternoon. ..Leitman.. 08/22/2019 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1245 AM CDT Thu Aug 22 2019 Valid 221200Z - 231200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE NORTHERN AND CENTRAL HIGH PLAINS AND FROM OK INTO THE MID-ATLANTIC AND NEW ENGLAND... ...SUMMARY... Isolated severe wind gusts are possible this afternoon and evening from Oklahoma eastward across the Ohio Valley and into parts of the mid-Atlantic and New England. Meanwhile, hail or wind, occasionally reaching severe levels, will also be possible over the central and northern High Plains area. ...Synopsis... A couple of upper level troughs and associated surface cold fronts will result in a few areas of strong, occasionally severe storms today. The first trough will pivot eastward from the upper Great Lakes to the Northeast. A band of stronger southwesterly deep-layer flow will overspread much of the northeastern U.S. from around PA northward while a surface cold front shifts eastward. The western extent of the front will drop more slowly south/southeast across the Midwest, extending from southern MO toward Chesapeake Bay by Friday morning. Several weak shortwave impulses and remnant MCVs will float through westerly flow from OK to the Mid-Atlantic ahead of the southward-sagging front, aiding in the development of sporadically strong thunderstorm clusters. Further northwest, a shortwave trough will migrate eastward across the northern Rockies. A surface cold front will progress eastward across MT/WY during the afternoon and evening, while a surface trough strengthens southeasterly low level flow in a moist upslope flow regime across the northern High Plains. This will focus another area for strong storm potential during the afternoon and evening across parts of the northern and central High Plains. ...Mid-Atlantic and New England... A warm and very moist airmass will reside ahead of the surface cold front. Overall, west/southwesterly flow will be rather modest, with the strongest flow residing over the Northeast. A corridor of modest destabilization will overlap with this relatively stronger flow, and a few fast moving storm clusters or line segments are possible from PA northward through coastal ME. A few strong wind gusts could accompany this activity, though the overall threat should remain limited by poor midlevel lapse rates and in the absence of stronger shear. Further south toward the Chesapeake and VA/NC Piedmont vicinity, thunderstorm clusters are expected to develop in vicinity of a lee trough as subtle shortwave impulses migrate across the Appalachians. The airmass across this area will be very moist with PW values greater than 2 inches forecast. Strong heating will result in moderate destabilization and some strong gusts in wet microbursts will be possible. ...Oklahoma toward the Ohio Valley... Deep-layer westerly flow will remain weak across the region. However, several shortwave impulses are forecast to migrate through westerly flow while a myriad of outflow boundaries and MCVs from prior convection influence thunderstorm development during the afternoon. Steep lapse rates and moderate instability will be sufficient for severe storms, but weak flow will limit overall organization. Nevertheless a few strong to severe storms are possible with strong downburst winds being the main threat. Should an adequate cold pool develop, very steep low level lapse rates could support a surging cluster/bow with an increased threat for damaging wind, but confidence in this scenario is low, precluding higher probabilities. ...Portions of the Northern/Central High Plains... Strong southeasterly upslope flow in the vicinity of a pre-frontal lee trough will bring upper 50s to low 60s surface dewpoints across the High Plains of MT/WY/CO. Strong heating and very steep midlevel lapse rates will result in 2000-3000 J/kg MLCAPE by afternoon. While southeast flow through around 2 km will be strong, mid and upper-level flow will remain rather weak. Nevertheless, as forcing increases with the approach of a surface cold front and the upper trough, scattered thunderstorms are expected. A deeply mixed sub-cloud layer will support strong downburst winds, especially as clusters/line segments are favored. However, very steep midlevel lapse rates also will support some potential for hail initially. In the absence of stronger shear, will maintain Marginal risk. Further west across the higher terrain of south-central into southwest MT, a couple of storms could produce gusty winds and hail as the cold front moves through during the early afternoon. ..Leitman.. 08/22/2019 Read more