SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1130 AM CDT Fri May 09 2025 Valid 091630Z - 101200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM THE EASTERN FLORIDA PENINSULA INTO SOUTHEAST GEORGIA AND FAR SOUTHERN SOUTH CAROLINA...AND ACROSS EASTERN NORTH CAROLINA/FAR SOUTHEAST VIRGINIA... ...SUMMARY... Thunderstorms capable of producing large hail and severe wind gusts are possible across parts of the Mid-Atlantic and Southeast, especially from the eastern Florida Peninsula through southeast Georgia, and across northeastern North Carolina/far southeast Virginia. ...Synopsis... Recent satellite imagery shows a pair of cyclones embedded within a large positively titled upper trough extending from the southern Plains through the Northeast. The northernmost/easternmost cyclone is centered over the Lower Great Lakes vicinity, and is forecast to move gradually eastward throughout the day, ending the period over southern New England. An associated surface low, which is currently centered over eastern NJ, is forecast to progress northeastward while becoming increasingly aligned with the mid-level cyclone. A cold front extends southwestward from this low across VA and then back westward across KY, southern IL, and central MO. As the low moves northeastward, this front is expected to gradually push southward/southeastward, moving through much of the Mid-Atlantic by this evening. The southernmost/westernmost embedded cyclone is currently centered over southern AR, and the expectation is for the cyclone to shift southeastward throughout the day, ending the period over the Lower MS Valley. Primary surface low associated with this system is currently over the northwest Gulf. This low is forecast to progress slowly eastward along the central Gulf coast, remaining just off shore and likely reaching just off AL/MS border intersection by early tomorrow morning. ...Central Gulf Coast into FL... A modest, convectively enhanced vorticity maximum is forecast to move from the central FL Panhandle into southeast GA/northern FL today, well ahead of the mid-level cyclone and associated surface low described in the synopsis. Localized ascent attendant to this features coupled with modest large-scale forcing for ascent and airmass destabilization will result in early-afternoon thunderstorm development, particularly along any sea breeze boundary that develops. Vertical shear will be modest, resulting in a mostly multicellular mode. Even so, updrafts are still expected to be strong enough to produce damaging downbursts and isolated large hail. Later tonight, some additional organization/strengthening of a convective line near the surface low is possible. Some strengthening of the low-level flow could occur at the same time, resulting in a low-probability tornado risk along the coast from AL into the western and central FL Peninsula. ...Mid-Atlantic into the Carolinas... Afternoon thunderstorm development is anticipated across the region, with the highest coverage from the VA Tidewater into east-central NC, where forcing along the cold front will be strongest. The strongest shear is anticipated across this region as well, but the overall magnitude should still be modest, with most guidance suggesting deep-layer shear around 35 kt. Buoyancy will be modest as well, with MLCAPE likely maximizing around 800 to 1000 J/kg. These environmental conditions support the potential for a few stronger, more organized updrafts capable of damaging wind gusts and isolated large hail. ..Mosier/Squitieri.. 05/09/2025