Post by SKYSUMMIT on Jul 6, 2024 14:08:15 GMT -6
Mesoscale Precipitation Discussion 0575
NWS Weather Prediction Center College Park MD
235 PM EDT Sat Jul 06 2024
Areas affected...Southeast Texas
Concerning...Heavy rainfall...Flash flooding possible
Valid 061834Z - 070000Z
SUMMARY...Slow-moving storms are developing along a stationary
boundary across southeast Texas. Urban and small stream flash
flooding possible.
DISCUSSION...Slow moving storms have developed along a stationary
boundary across southeast Texas this afternoon. The boundary is
acting as a focusing mechanism for the storms, as 10 kt
southeasterly flow at the surface advects deep tropical moisture
into the boundary. Without much other forcing in the area, the
storms have been taking advantage of PWATs of 2.2 inches as
depicted in SPC Mesoanalysis and SBCAPE values up to 4,000 J/kg to
produce very heavy rainfall in the area. Rainfall rates with the
storms south and southwest of Beaumont have been approaching 2
inches per hour. Storm motions are slow...with the biggest storms
moving the fastest towards the west at 10-15 mph...while the
smaller cells have been mostly stationary.
CAMs guidance is in fair agreement noting the developing
convection in southeast Texas. The continued slow westward motion
is in good agreement, whereas the evolution more towards the north
inland into Texas or more south towards Victoria is still
uncertain. Since the strongest cells have been developing where
the stationary boundary is closest to the coast (the Beaumont
area)...it seems more probable that storm development will be tied
in at least some way to the moisture influx off the Gulf.
Thus...leaning towards those solutions that bring more convection
southwestward along the coast with time.
Later this afternoon, the approach of the wind field of T.S. Beryl
will turn the prevailing flow in the Gulf towards the
northeast...resulting in a rapid diminishing of the convective
coverage in much of the CAMs guidance while also driving the
convection west along I-10. Increasing distance from the Gulf and
a faster westward motion will diminish the flash flooding threat.
Urban and small stream flash flooding will be the greatest threat
with these storms in and around the Houston area.
Wegman