Mesoscale Precipitation Discussion 0943
NWS Weather Prediction Center College Park MD
929 AM EDT Mon Oct 08 2018

Areas affected...TX Panhandle & Western OK

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

Valid 081328Z - 081728Z

Summary...A convective uptick is underway across the TX Panhandle
and western OK at the current time.  Hourly rain totals to 2" and
local amounts to 4" are expected over the next four hours.

Discussion...Thunderstorms are increasing in coverage across
portions of the TX Panhandle and western OK per recent radar
imagery.  This is occurring within a very divergent area aloft
ahead of a slowly progressive closed low over the Desert
Southwest.  Precipitable water values of 1.2-1.6" lie in the area
per recent GPS data.  Inflow at 850 hPa in convergent out of the
south-southwest at 25-45 kts (similar to the magnitude of the
effective bulk shear), importing ML CAPE values (as little CIN
exists) of 1000-2000 J/kg within the warm area advection pattern
north and east of a wave of low pressure.  The flow is
unidirectional out of the south-southwest, with moisture aloft
advecting in from the eastern Pacific.

Hourly rain totals to 2" are expected within this environment. 
There is a mesoscale guidance signal within the 00z WRF NSSL and
00z NMMB guidance (which look reasonable) for local amounts of 4"
in this area, which the 06z HREF probabilities of 1"+ an hour
suggest could persist for the next four hours.  Slow eastward
progression should keep the rainfall magnitude from becoming too
extreme.  Flash flood guidance values in this area are roughly
2-2.5" in three hours, which could be exceeded during this time
frame.

Roth

ATTN...WFO...AMA...DDC...ICT...LUB...OUN...

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

LAT...LON   38069796 37309698 35659852 33850098 33480239
            34810194 34990186 36619990