Mesoscale Precipitation Discussion 1066
NWS Weather Prediction Center College Park MD
1011 AM EST Wed Dec 26 2018

Areas affected...North Central TX...Central OK

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

Valid 261510Z - 262110Z

Summary...Probability of convection with hourly totals exceeding
1" will increase through the morning and into the afternoon hours
and could pose a localized flash flood threat.

Discussion...An approaching mid level shortwave currently over the
Southwest US will enhance forcing for ascent across the region
into the afternoon hours. A broad axis of deeper moisture,
characterized by recent PWATs per blended TPW product of 1-1.2",
will lift northward. At the surface, a quasi-stationary boundary
was analyzed across the panhandle of TX into west-central OK.
South of this boundary, SBCAPE instability was on the order of a
few hundred J/kg, but is expected to increase into the afternoon.
The latest run of the HREF shows probabilities of exceeding 500
J/kg SBCAPE approach almost reaching the Red River. However, there
should be sufficient MUCAPE (1000 J/kg off latest HREF mean)
extending well into west-central OK. Wind fields are expected to
be convergent in the low levels, especially as a cold front
approaches this afternoon. In general, storm motions will align
nearly parallel to the mean winds, suggesting potential for
training convection.

Recent radar and satellite imagery shows convection beginning to
blossom and IR cloud tops continuing to cool. Recent mesonet
observations show hourly totals approaching 1" in places and this
generally matches what area radars are suggesting.

Through 21z / 3pm CT, the heaviest rainfall is expected to be
aligned nearly north-south across portions of north-central TX
into west-central OK. Latest trends in the hi-res models show
potential for 2-3" with locally higher amounts possible.

Mitigating factors for flash flooding however are the dry
antecedent conditions. Latest rainfall analysis shows 7-day
percent of normal across the area at 5-10 percent. Thus, with the
higher FFG values (1-hr 2-2.5"), any flooding concerns may be more
localized over sensitive or urban areas.

Taylor

ATTN...WFO...AMA...FWD...LUB...MAF...OUN...SJT...

ATTN...RFC...ABRFC...WGRFC...

LAT...LON   35999780 34679721 32779805 31259941 31750054
            33250073 34740030 35939949