Convective Outlook
SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0220 AM CDT Tue Sep 17 2019 Valid 191200Z - 201200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS OVER PARTS OF THE NORTHERN PLAINS... ...SUMMARY... At least isolated storms producing large hail are possible Thursday evening and overnight over the northern High Plains. ...Synopsis... An upper trough will continue to slowly move east across the Great Basin and toward the Rockies with increasing south/southwest flow aloft into the northern High Plains. Meanwhile, an upper high will remain situated over the Southeast, with a surface high over the Mid Atlantic maintaining dry conditions there. Southerly winds over the Plains will maintain 65-70 F dewpoints from TX to MN, with a tropical disturbance possibly over eastern TX. The slow-moving western trough will also create lift over the northern High Plains as a cold front encounters an unstable air mass Thursday afternoon into Friday. ...Northern High Plains... Low pressure will develop over eastern WY during the afternoon with a wind shift over eastern MT. Southeast surface winds will maintain moist and unstable conditions over the Dakotas and Nebraska during the day, with continued northwestward warm advection during the evening with a 40-50 kt low-level jet. Steepening lapse rates aloft combined with sufficient deep-layer shear will support at least isolated severe storms capable of damaging hail. Locally damaging winds cannot be ruled out, although the majority of the storms are expected overnight. ..Jewell.. 09/17/2019Read more
Updated 17 September 2019 | 2:25 am
SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1234 AM CDT Tue Sep 17 2019 Valid 181200Z - 191200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... A few strong thunderstorms are possible across parts of the Upper Midwest Wednesday afternoon and evening, but the risk for severe weather appears low. ...Synopsis... An upper trough will shift east across the Pacific Northwest and Great Basin, with strong upper-level southwesterlies and cooling aloft approaching the Rocky Mountains into Thursday morning. Ahead of this trough, a fast-moving, compact shortwave trough will move from MN into Ontario while an upper ridge remains over the mid and lower MS Valley. Beneath the upper ridge, a warm core disturbance is forecast to move into southeast TX, providing heavy precipitation. At the surface, a weak front will stall over the northern Plains behind the leading wave, with a moist air mass extending southwest to the Gulf of Mexico. ...Eastern NE into western WI... Storms may be ongoing Wednesday morning associated with a low-level jet and warm advection from IA into MN and northwest WI. Shear will be weak but plenty of instability will support heavy rain, gusty winds. Severe weather is not anticipated, but a locally strong wind gust or marginal hail report cannot be ruled out during the afternoon as isolated storms regenerate along the weak boundary. ...Upper TX Coast... A disturbance in the northwest Gulf of Mexico is forecast to move northwestward into southeast TX, with the primary concern very heavy rainfall. Predictability is low regarding wind fields and thus tornado risk. Should the system become stronger than currently forecast, shear profiles may necessitate low tornado probabilities in later outlooks. ...MAXIMUM RISK BY HAZARD... Tornado: Read moreUpdated 17 September 2019 | 12:49 am
SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1236 AM CDT Tue Sep 17 2019 Valid 171200Z - 181200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF THE NORTHERN HIGH PLAINS AND THE UPPER MIDWEST... ...SUMMARY... A few strong/severe storms are expected across the northern high Plains area afternoon/early evening, and may evolve overnight into the Upper Midwest. Hail and locally damaging winds will be possible. ...Northern Plains to the Upper Midwest... A shortwave impulse over SD early this morning will continue to lift northeast across MN. Ongoing convection associated with this feature will spread across MN through midday and should remain elevated. This activity is not expected to be severe given the elevated nature of convection. Further southwest, a compact shortwave trough is forecast to lift northeast from the Great Basin to the eastern Dakotas/western MN by Wednesday morning. A surface low near the eastern MT/western ND/SK border will deepen during the afternoon as height falls begin to overspread the region. a surface trough/dryline will extend southward through the northern/central High Plains while a cold front shifts east across eastern MT by 00z. Deep layer flow will strengthen considerably as a mid/upper level jet streak overspreads the central High Plains and steep midlevel lapse rates will aid in modest destabilization by late afternoon. However, coverage/intensity of storms remains somewhat uncertain given a considerable dry slot and capping on the western fringes of the Midwestern upper ridge. Nevertheless, at least a few storms are expected near the triple point over eastern MT into northeast WY. Strong gusts and marginal hail will be possible with the strongest cells as they shift east/northeast. Additional storms are expected to develop over eastern SD into MN after 03z ahead of the eastward-surging cold front. Storms should quickly grow into clusters or line segments as a 40-50 kt southwesterly low level jet increases. Strong gusts will be possible with the strongest cells, though forecast soundings suggest convection may remain elevated. ..Leitman.. 09/17/2019Read more
Updated 17 September 2019 | 12:45 am