SPC AC 301729

   Day 2 Convective Outlook  
   NWS Storm Prediction Center Norman OK
   1229 PM CDT Thu Jul 30 2020

   Valid 311200Z - 011200Z

   ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS OVER EASTERN NEW
   MEXICO...PORTIONS OF THE SOUTHERN PLAINS EAST TO THE MID-MISSISSIPPI
   VALLEY...AND OVER THE MID-ATLANTIC REGION FRIDAY...

   ...SUMMARY...
   Severe thunderstorms may impact portions of the southern Great
   Plains into the Ozark Plateau and Mid South vicinity Friday.
   Isolated severe storms will also be possible across the mid-Atlantic
   region and eastern New Mexico. Strong/locally damaging winds and
   isolated large hail will be the primary threats.

   ...Synopsis...
   Upper-level flow across the CONUS Friday will be primarily
   influenced by high pressure centered over the southwest U.S. with a
   ridge extending northward to the international border, and a
   positively-tilted trough from the mid-Mississippi Valley across east
   Texas. Farther north, upper-level lows will be located west of the
   British Columbia coast, the Hudson Bay region, and the Canadian
   Maritime provinces. At the surface, an expansive front, reinforced
   by convective outflows, will extend from the Delmarva Peninsula to a
   weak surface low near the Missouri Bootheel and then across
   central/west Texas Friday afternoon. A cold front will also move
   east/southeast across the upper Midwest and northern Plains/Rockies.
   Tropical Storm Isaias is expected to move through the Bahamas Friday
   and Friday night. Please consult the latest NHC forecast for
   additional information.

   ...Southern Plains into mid-Mississippi Valley...
   The portion of the front from the surface low southwestward is
   expected to move south during the forecast period, as a
   convectively-enhanced upper-level vorticity maximum moves slowly
   southeast in the AR vicinity. Strong daytime heating should result
   in moderate/pockets of strong MLCAPE by afternoon.  Somewhat
   stronger flow aloft with the MCV will contribute to 25-30 kts of
   effective shear across the Arklatex east to the mid-Mississippi
   Valley. Thunderstorms are expected to develop near and in advance of
   the front, with mainly multicells expected, though weak supercell
   structures will be possible.  Although damaging winds and hail will
   be the primary severe threats, some risk of a tornado will also
   exist in the vicinity of the surface low where low-level SRH should
   be locally enhanced. 

   Higher severe probabilities may eventually be needed for portions of
   this area as the effects of Day 1 convection become clearer.

   Farther southwest across central/west TX thunderstorms should
   redevelop/re-intensify along the front as it moves into a strongly
   unstable air mass.  Weaker vertical shear will be present, however
   the presence of substantial DCAPE suggests that damaging gusts and
   isolated instances of hail will be possible with clusters of
   thunderstorms during the afternoon/evening.

   ...Mid-Atlantic Region...
   A very moist air mass will exist south of the front characterized by
   PW values in excess of 2 inches, and strong daytime heating will
   result in steepening low-level lapse rates and contribute to
   moderate/strong MLCAPE. Deep-layer shear, while remaining modest,
   will be locally 25-30 knots and supportive of some degree of storm
   organization. Thunderstorms developing during the afternoon will
   move east with an attendant risk for strong/locally damaging gusts.

   ...New Mexico...
   Isolated thunderstorms are expected to develop during the
   afternoon/evening aided by moistening upslope flow. Mid-level lapse
   rates will be noticeably steeper in this region, and 35-40 knots of
   northwesterly deep shear will support mid-level storm rotation as
   storms move southeast/south through evening.  Damaging gusts and
   large hail will be possible.

   ...South Florida...
   Tropical Storm Isaias will remain southeast of the south Florida
   coast through 12z Saturday (consult the latest NHC forecast for
   specific information on track and intensity). Although the risk for
   thunderstorms may increase across the area Friday night, uncertainty
   regarding the location, intensity, and spatial extent of the wind
   field preclude severe probabilities with this outlook.

   ..Bunting.. 07/30/2020

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