Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0758 AM CDT Sat Jul 08 2017 Valid 081300Z - 091200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE CAROLINAS AND SOUTHERN VA... ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM THE CENTRAL PLAINS TO THE SOUTHEAST STATES... ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS THE FL PENINSULA... ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS THE NORTHEAST STATES/NEW ENGLAND... ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS SOUTHERN ARIZONA... ...SUMMARY... Isolated severe thunderstorms are expected from the central Plains to the Carolinas and Mid-Atlantic States, and across New England. Localized damaging wind gusts are most likely, with large hail most probable over the Plains. Isolated strong wind gusts are possible across southern Arizona as well. ...Carolinas/mid-Atlantic States... Thunderstorms should diurnally increase this afternoon initially near the mountains/higher terrain where differential cloud cover may also be an influence near and ahead of an advancing cold front. As the front continues to spread east-southeastward, storms should increase in coverage and organization/intensity by late this afternoon into evening as they move into a more unstable air mass across the Piedmont and coastal plain. Somewhat stronger forcing for ascent/vertical shear should also influence the region later today via the approach of a modestly amplifying upstream trough. Multiple eastward-moving clusters of strong to severe thunderstorms are probable this afternoon and evening especially across NC/southern VA, with localized wind damage as the primary risk. ...Northeast States/New England... An upper trough/speed max over the lower Great Lakes vicinity early today will continue east/northeastward toward New England. While forcing for ascent and vertical shear will increase across the region today, semi-prevalent cloud cover and early-day precipitation cast some uncertainty regarding the exact degree of destabilization ahead of the eastward-moving front. Even so, sufficient destabilization should exist for some of the stronger storms to produce severe hail/wind. A categorical Slight Risk upgrade could be warranted if confidence in somewhat greater destabilization would increase. ...Central Plains... In the presence of moderately strong north/northwesterly flow aloft, storms appear most likely to develop across parts of NE this afternoon in vicinity of a surface low and weak front with storms also potentially spreading into portions of western and central KS. Modest amounts of buoyancy and deep-layer shear could yield isolated severe storms capable of severe hail and wind mainly late this afternoon into evening. ...South-central Plains to lower Mississippi Valley... Storms should diurnally intensify along/south of an effective front and generally along the southern/eastern periphery of existing early-day storm clusters. Deep-layer shear will be weak, but ample moisture and instability will support the potential for some locally severe thunderstorms capable of damaging winds and possibility pulse-type bouts of severe hail. ...Southern Arizona... On the southern periphery of the upper ridge centered over NV/southern UT/northern AZ, moisture will continue to increase into the region today along with the possibility of a modest strengthening of easterly mid-level winds (15 kt or greater). Storms should diurnally increase over the mountains/rim vicinity and possibly in a more isolated sense across other parts of the desert floor, with these storms subsequently spreading westward through the late afternoon and evening hours. Localized strong with gusts will be possible as the storms encounter a hot/deeply mixed boundary layer. ...Florida Peninsula... The thermodynamic environment appears marginally supportive of the possibility of locally damaging wind gusts particularly as sea breeze-related development occurs across the central/southern FL Peninsula this afternoon. ..Guyer.. 07/08/2017Read more
from SPC Forecast Products http://ift.tt/rATNzD
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