Mesoscale Precipitation Discussion 0280
NWS Weather Prediction Center College Park MD
1128 PM EDT Sat Jun 05 2021
Areas affected...Northeast Texas...Far Southern Oklahoma
Concerning...Heavy rainfall...Flash flooding possible
Valid 060328Z - 060700Z
Summary...Isolated flash flooding may continue across portions of
North Texas and far southern Oklahoma through the early overnight
hours with rainfall rates as high as 2-3"/hr.
Discussion...Deep convection is expanding across portions of
northeastern Texas late this evening, amid a highly favorable
mesoscale environment for heavy rainfall (as well as relatively
slow storm motions). SPC mesoscale analysis indicates MLCAPE of
1000-1500 J/kg, PWATS of 1.7-1.8 inches (above the 90th percentile
for FWD), and effective bulk shear of near 20 kts. In addition,
the placement of a synoptic scale upper-level low over central TX
is providing a fair amount of divergence/diffluence aloft. These
factors, along with a weak low-level jet (20 kts) and modest
925-850 mb moisture transport, should continue to foster upscale
growth of convection over the next several hours.
The just in 00z HREF suite also suggests that convection will be
able to continue to proliferate through 06z. The probability
matched mean (PMM) QPF suggests an additional 2-3" is possible
over a fairly broad area over northeastern Dallas and points
northeastward (toward far southern Oklahoma). The current
convective trends bear this out, as radar and satellite imagery
depict continued storm mergers and outflow enhanced convergence
over an analyzed region of deep moisture convergence. 00z HREF
40-km neighborhood probabilities suggest a 30% chance of 3-inch
exceedance over the next several hours. This 3-inch exceedance has
already been realized just north of Dallas (near Allen, TX),
according to dual-pol radar estimates via KFWS (as well as MRMS
3-hr QPF through 03z) which depicts an area where 5+ inches of
rain has already fallen. Hydrologically, much of the surrounding
area is already relatively saturated, as NASA SPoRT-LIS soil
moisture percentiles average above the 70th percentile.
Given these latest convective trends, the 00z CAM output, and
antecedent soil conditions, flash flooding will continue to be
possible through 07z. Of particular concern is the prospect of
convection backward-propagating farther into the Dallas-Fort Worth
metro area, given the relatively slow storm motions and high
rainfall rates.
Churchill
ATTN...WFO...FWD...OUN...SHV...TSA...
Winter time post are almost exclusively focused on the DFW area.
even up here I saw a 90 on the 10 day last night
