SPC Mar 7, 2018 0600 UTC Day 1 Convective Outlook

By Newsroom America Feeds at 7 Mar 2018

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1140 PM CST Tue Mar 06 2018 Valid 071200Z - 081200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Isolated thunderstorms are possible across the southern half of Florida into the afternoon, while lightning strikes cannot be ruled out across parts of the Northeast. Severe weather is not expected. ...Synopsis... A longwave trough will be maintained across the eastern half of the U.S. this forecast period with upstream ridging in the west. A progressive shortwave trough will become negatively tilted as it tracks from the base of the eastern trough (in lee of the southern Appalachians at 12Z today) through the middle Atlantic Coast states into New England. Surface cyclogenesis should be underway near of just off the Delmarva Peninsula at the start of the forecast period, with deepening expected as this low tracks to the Atlantic waters south of Long Island/New England by 00Z, then through southeast MA toward ME tonight. The southern extent of a trailing cold front will advance through southern FL today and offshore into the Florida Straits tonight. ...Southern half of FL... Some diabatic heating and boundary-layer moistening ahead of the cold front will contribute to weak buoyancy for convection, as the presence of weak deep-layer lapse rates precludes stronger destabilization. Veering low-level winds should weaken frontal convergence, with the potential for deep moist convection diminishing into the afternoon as the cold front advances southward. Isolated thunderstorms will be possible, with severe-weather not expected. ...NJ/southeast NY to southern New England... Forecast soundings indicate the occurrence of steepening midlevel lapse rates as strong low-level warm air advection/deep-layer ascent spreads from the northern middle Atlantic coast to southern New England this morning into the afternoon/evening, in association with the deepening cyclone. MUCAPE up to 100-200 J/kg should be rooted between 700-850 mb per forecast models, suggesting the likelihood for elevated thunderstorms, initially in vicinity of NJ this morning and developing into southern New England by this afternoon. While severe-weather is not expected with these elevated storms, enhanced precipitation rates could occur. ..Peters/Karstens.. 03/07/2018 Read more



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