ZCZC SPCSWOD48 ALL
   ACUS48 KWNS 080859
   SPC AC 080859

   Day 4-8 Convective Outlook  
   NWS Storm Prediction Center Norman OK
   0359 AM CDT Wed Apr 08 2020

   Valid 111200Z - 161200Z

   ...DISCUSSION...
   While considerable uncertainties remain, a substantial severe
   episode appears possible this weekend, from Texas into portions of
   the lower MS Valley on Saturday, and especially from the lower MS
   Valley into portions of the Southeast on Sunday. 

   ...D4/Saturday: Southern Plains into the Arklatex/Lower MS Valley...

   Extended-range guidance continues to vary regarding the timing of
   the ejecting cutoff low over the Southwest, though all solutions are
   in generally good agreement in the development of a deep surface low
   over the central/southern High Plains on Saturday as the upper low
   ejects eastward. As low-level moisture streams northward, moderate
   destabilization appears possible as far north as the Red River, as
   deep-layer shear increases in advance of the ejecting trough. Severe
   thunderstorm development will be possible during the
   afternoon/evening across much of TX. Late Saturday night, an
   increasing low-level jet may help to advect very rich low-level
   moisture inland and potentially provide an additional focus for an
   overnight severe thunderstorm threat from the TX Gulf Coast into the
   lower MS Valley. 

   ...D5/Sunday: Arklatex/Lower MS Valley into the Southeast...

   Timing differences continue among the extended-range guidance into
   D5/Sunday, with the GFS notably faster, while the 08/00Z ECMWF has
   trended slower compared to other guidance as well as its own
   previous cycles. Regardless of timing, most guidance depicts the
   ejecting trough as taking on a neutral to negative tilt, with a
   deepening surface low moving into portions of the MS/TN Valleys.
   While the northward extent of substantial destabilization remains
   uncertain due to the potential for widespread convection, sufficient
   instability and increasing low-level and deep-layer shear will
   support a severe thunderstorm threat across much of the Southeast
   throughout the day into Sunday night. If very rich low-level
   moisture (low 70s dewpoints) over the Gulf can spread inland in
   advance of this dynamic system, as depicted by recent ECMWF/UKMET
   runs, then a substantial severe thunderstorm event could evolve,
   with all hazards possible. Higher probabilities will be required if
   guidance continues to trend in that direction. 

   The severe threat could spread into portions of the Carolinas and
   mid Atlantic on Sunday night, though too much uncertainty remains
   regarding the northward extent of surface-based destabilization to
   include probabilities for those areas at this time. 

   ...D6/Monday: Mid Atlantic southward to Florida...

   If the slower guidance verifies regarding the eastward movement of
   the surface low and attendant cold front, some severe threat will
   persist into D6/Monday from the Mid Atlantic southward along the
   Southeast coast. Predictability is too low to delineate any
   probabilities for D6/Monday at this time.

   ..Dean/Dial.. 04/08/2020

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