Mesoscale Precipitation Discussion 0366
NWS Weather Prediction Center College Park MD
323 PM EDT Sun Jun 20 2021

Areas affected...portions of North and South Carolina

Concerning...Heavy rainfall...Flash flooding possible

Valid 201922Z - 210122Z

Summary...Gradually increasing convective coverage could result in
a few areas of flash flooding this afternoon and evening.

Discussion...Ahead of the eventual path of TD Claudette, strong
insolation amid a moist and increasingly buoyant airmass
(characterized by 2-2.3 inch PW values and around 2000 J/kg
MLCAPE) was fostering robust convective development recently.  The
storms are in an environment with southwesterly flow aloft and
were moving northeastward at around 15-20 knots.  However, the
weak low-level confluence and orientation of the development was
allowing for convection to repeat/develop in areas that have
received around 1-3 inches of rain earlier and have FFG values
ranging from 1-2 inch-per-hour thresholds.  The very moist airmass
was allowing for rainfall rates to exceed these thresholds beneath
the heavier updrafts (up to around 2.5 inches per hour at times),
suggesting that at least a spotty flash flood threat should
materialize especially wherever training convection can occur.

Over time, convective coverage should continue to increase through
at least sunset due to continued insolation and low-level
convergence ahead of Claudette.  There may be a downtick in
convective coverage thereafter due to loss of insolation, although
the moist environment should still sustain a few lingering storms
after sunset especially where updrafts can ingest non-convectively
modified air.

Cook

ATTN...WFO...AKQ...CAE...CHS...GSP...ILM...MHX...RAH...

ATTN...RFC...SERFC...NWC...

LAT...LON   36507687 35757645 35247670 34627730 33947811
            33447893 32747988 32568062 32898137 33258164
            34078207 34768161 35558024 36197842