SPC Mar 1, 2018 1730 UTC Day 2 Convective Outlook

By Newsroom America Feeds at 1 Mar 2018

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1038 AM CST Thu Mar 01 2018 Valid 021200Z - 031200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Thunderstorms will be possible along the West Coast on Friday. ...Synopsis... A large cyclone is expected to mature just off the New England coast during the first half of the period before then progressing slowly eastward as a vertically stacked, mature system. At the same time, shortwave ridging will move gradually across the Plains into the MS Valley and upper troughing will deepen over the Pacific Northwest and northern Great Basin. A shortwave trough is expected to pivot through the Pacific Northwest trough through the northern Great Basin and northern Rockies. Enhanced southwesterly flow aloft accompanying this system will spread eastward as well, encouraging a deepening of the surface lee trough stretching across the High Plains. Resulting increase in the surface pressure gradient supports a strengthening of southerly winds across the Plains but favorable low-level moisture, which will have recently been scoured out by a frontal passage on Thursday, will remain confined to deep south TX. Consequently, stable conditions will preclude thunderstorm activity west of the Rockies. Isolated lightning strikes will be possible along the northern and central portions of West Coast, particularly from northern CA through OR, as a shortwave trough pivots around the upper low, providing forcing for ascent amidst the post-frontal, steep lapse rate environment. Some small hail will be possible with the strongest storms. Additionally, given the strongly veered low-level flow, a tornado cannot be completely ruled out along the immediate northern CA/southwest OR coast. However, limited instability suggests updrafts will have difficultly maintaining strength with cells likely exhibiting more episodic pulses of greater updraft intensity. ..Mosier.. 03/01/2018 Read more



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