MESOSCALE PRECIPITATION DISCUSSION 0714
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
1007 PM EST SUN DEC 27 2015
 
AREAS AFFECTED...FAR SOUTHERN MO...EXTREME EASTERN
OK...AR...LA...FAR EASTERN TX... 
 
CONCERNING...HEAVY RAINFALL...FLASH FLOODING LIKELY 
 
VALID 280300Z - 280900Z
 
SUMMARY...SLOW-MOVING AND VERY HEAVY SHOWERS AND THUNDERSTORMS
CONTINUE TO FOCUS AN ELEVATED THREAT OF FLASH FLOODING.

DISCUSSION...A STRONG MID LEVEL LOW CENTER IS GRADUALLY MOVING
EAST ACROSS THE RIO GRANDE VALLEY THIS EVENING AND WILL BE LIFTING
INTO THE ARKLATEX REGION BY EARLY MON MORNING. THIS WILL GRADUALLY
DRIVE AN OCCLUDED CYCLONE NORTH OUT OF FAR EASTERN TX AND UP ALONG
THE OK/AR BORDER LATER TONIGHT WITH A TRAILING COLD FRONT THAT IS
SLOWLY CROSSING THE WESTERN GULF COAST AREA.

STRONG MOISTURE TRANSPORT AHEAD OF THE COLD FRONT AND A MODEST
LEVEL OF INSTABILITY CONTINUES TO FOSTER NUMEROUS N/S ORIENTED
BANDS OF COLD-TOPPED CONVECTION ACROSS FAR EASTERN TX/WESTERN LA
AND NORTH INTO FAR EASTERN OK AND WESTERN AR...ALONG WITH SEVERAL
EMBEDDED OVERSHOOTING TOPS AS PER THE LATEST GOES-OTD ALGORITHM.
THE CONVECTION IS BEING AIDED BY VERY STRONG DIVERGENCE ALOFT/DEEP
LAYER ASCENT AHEAD OF THE HEIGHT FALLS INVOLVING THE MID LEVEL LOW
CENTER...AND THIS STRONG FORCING WILL PERSIST OVERNIGHT AS THE
ENERGY GRADUALLY FOCUSES OVER THE LOWER MS VALLEY.

IMPRESSIVE PW ANOMALIES PERSIST OVER THE LOWER MS VALLEY...WITH
1.6 TO 1.8 INCH PWATS AS PER 00Z RAOB DATA. THESE ANOMALIES ARE
UPWARDS OF 3 TO 4 STD DEV ABOVE NORMAL LOCALLY AND CONTINUE TO
FACILITATE INTENSE RAINFALL RATES OF 1 TO 2 INCHES/HR...AND
ESPECIALLY THE LAST COUPLE OF HOURS OVER FAR EASTERN TX AND NEAR
THE LA BORDER AND ALSO FAR SOUTHWEST AR WHERE COLDER CONVECTIVE
TOPS ARE NOTED.

ALL OF THIS ACTIVITY WILL SLOWLY SHIFT EAST OVERNIGHT...BUT EXPECT
AN ADDITIONAL 3 TO 6 INCHES OF RAIN LOCALLY OVER ESPECIALLY
NORTHERN LA AND SOUTHERN AR WHERE THE 12Z ARW AND 12Z NMMB SUGGEST
CONCENTRATED HEAVY RAINFALL AND APPEAR TO BE MORE REFLECTIVE OF
THE CURRENT ACTIVITY. ADDITIONAL AMOUNTS FARTHER NORTH SHOULD
GENERALLY BE 1 TO 3 INCHES GIVEN A LESSER DEGREE OF INSTABILITY.
IN ANY CASE...THE SATURATED SOIL CONDITIONS FOR MUCH OF THE REGION
WILL CONTINUE TO FAVOR LOCALLY EXTENSIVE FLASH FLOODING AND RUNOFF
CONCERNS THROUGH THE NIGHT.

ORRISON

ATTN...WFO...HGX...JAN...LCH...LZK...MEG...PAH...SGF...SHV...
TSA...

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

LAT...LON   37049304 36879170 36119048 34669062 32529141 
            30859189 29839264 29699378 29899453 30649502 
            31779510 33329525 34369531 35859505 36729420