SPC AC 091958

   Day 1 Convective Outlook  
   NWS Storm Prediction Center Norman OK
   0258 PM CDT Fri May 09 2025

   Valid 092000Z - 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.

   ...20Z Update...
   No changes were made to the forecast with this update. For details
   on the near-term severe risks in the Mid-Atlantic and
   northern/central FL, reference MCDs #753 and #754. For the overnight
   and early morning time frame, a locally favorable corridor for
   tornadoes/waterspouts may develop in the vicinity of the western FL
   Panhandle -- focused ahead of a well-defined MCV tracking eastward
   across the north-central Gulf. However, confidence in adding higher
   tornado probabilities is too low at this time, given
   ongoing/additional convection and related boundary-layer
   overturning.

   ..Weinman.. 05/09/2025

   .PREV DISCUSSION... /ISSUED 1130 AM CDT Fri May 09 2025/

   ...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.

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