SPC Apr 15, 2018 1730 UTC Day 2 Convective Outlook

By Newsroom America Feeds at 15 Apr 13:32

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1229 PM CDT Sun Apr 15 2018 Valid 161200Z - 171200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... A few strikes of lightning may accompany convection across portions of the Northeast early in the period. Isolated thunderstorms will also be possible across parts of the western United States. ..Northeast... A large closed mid-upper level low will maintain a negative tilt Monday into Monday night, as it shifts northeast across much of the northeast quadrant of the United States. A progressive midlevel shortwave trough moving through the eastern periphery of the parent closed low should shift northeast away from the Middle Atlantic States early Day 2, reaching New England by Monday afternoon. Meanwhile, an upstream midlevel shortwave trough will track quickly through the southern periphery of the closed low, moving through the Ohio Valley Monday afternoon to the Middle Atlantic region and southern New England Monday night. Forcing for ascent attendant to the lead shortwave trough should aid in the potential for strong to severe storms across portions of the Middle Atlantic States including the Delmarva Peninsula late Day 1. Current forecast timing suggests this forcing for ascent should move offshore at the start of Day 2 such that the introduction of a severe risk area is not warranted at this time. However, if the attendant cold front is slower than current thinking, then a Marginal severe risk may be needed for parts of the Delmarva Peninsula into southern NJ. A modified warm sector will struggle to advance into southern New England as strong height falls and strong warm advection aid in elevated convection north of a warm front residing near the southern New England coast. Despite forecast soundings suggesting MUCAPE of a few hundred J/kg rooted around 700 mb not becoming deep enough for charge separation, the strength of the dynamics with the negatively tilted trough should allow for a few lightning strikes accompanying the strongest elevated convection. ...Western United States... A large mid-upper level trough with cold 500-mb temperatures will advance inland across much of the western U.S. this forecast period. Despite precipitable water being seasonally low, forcing for ascent and some destabilization/steepening lapse rates accompanying a few embedded shortwave troughs should support a few thunderstorms from OR and CA northeast to MT. Small hail cannot be ruled out with elevated storms in eastern MT Monday night. ..Peters.. 04/15/2018 Read more



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