MESOSCALE PRECIPITATION DISCUSSION 0036
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
1003 AM EST FRI FEB 23 2018

AREAS AFFECTED...NORTHERN TX...SOUTHERN/EASTERN
OK...WESTERN/CENTRAL AR

CONCERNING...HEAVY RAINFALL...FLASH FLOODING POSSIBLE

VALID 231500Z - 232100Z

SUMMARY...ADDITIONAL HEAVY RAINS ARE EXPECTED OVER SATURATED
SOIL...LOCALLY SIGNIFICANT RUNOFF AND/OR FLASH FLOODING CONCERNS
WILL CONTINUE.

DISCUSSION...THE GOES-16 RGB AIRMASS IMAGERY SHOWS A WELL-DEFINED
SHORTWAVE IMPULSE LIFTING NORTHEAST ACROSS CENTRAL TX THIS MORNING
WHICH IS EMBEDDED WITHIN AN OTHERWISE VERY MOIST SOUTHERN STREAM
UPPER JET THAT IS CONTINUING TO BRING MID AND HIGH LEVEL
SUBTROPICAL MOISTURE NORTHEAST FROM THE EASTERN TROPICAL PACIFIC
AND UP ACROSS MAINLAND MEXICO AND ADJACENT AREAS OF THE SOUTHERN
PLAINS AND LOWER MS VALLEY REGION.

MEANWHILE...A WELL-DEFINED POOL OF ELEVATED INSTABILITY IS NOTED
FROM 12Z RAOB DATA ACROSS MUCH OF CENTRAL TX AND EXTENDING DOWN TO
THE MIDDLE RIO GRANDE VALLEY. MUCAPE VALUES ARE EXCEEDING 1000
J/KG ACROSS AREAS OF NORTH-CENTRAL TX JUST TO THE SOUTH OF THE RED
RIVER AND THIS ENERGY WHICH IS EMBEDDED WITHIN A WELL-DEFINED WARM
ADVECTION PATTERN AHEAD OF THE SHORTWAVE TROUGH IS FOSTERING A
RATHER RAPID OUTBREAK OF ELEVATED CONVECTION. OVER THE LAST 1 TO 2
HOURS THERE HAS BEEN A GRADUAL INCREASE IN CONVECTIVE ORGANIZATION
ALONG WITH COOLING CLOUD TOPS AS SEEN IN GOES-16 IR SATELLITE
IMAGERY. RADAR IS SHOWING MULTIPLE SMALL SCALE CLUSTERS OF
CONVECTION GROWING IN COVERAGE WITH A COUPLE OF CELL-MERGERS CLOSE
TO OCCURRING.

OVER THE NEXT FEW HOURS...THE AFOREMENTIONED SHORTWAVE IS LIKELY
TO ALLOW HEAVY SHOWERS AND THUNDERSTORMS TO LIFT ACROSS
NORTH-CENTRAL TX AND THEN INTO SOUTHERN OK ACROSS THE RED RIVER AS
THE ENERGY INTERACTS FURTHER WITH THE NOSE OF A SOUTH/SOUTHWEST
LOW LEVEL JET OF 40 KTS AND WITH FAVORABLE MOISTURE/INSTABILITY
TRANSPORT. SOME EXPANSION OF CONVECTION BACK INTO WESTERN AR IS
POSSIBLE AS WELL.

EXPECT RAINFALL RATES OF AS MUCH AS 1 TO 1.25 INCHES/HR
LOCALLY...GIVEN THE AVAILABLE INSTABILITY AND GENERAL POOLING OF
1.2 TO 1.4 INCH PWATS SOUTH OF THE RED RIVER WHICH WILL BE LIFTING
NORTHEAST THROUGH MID-AFTERNOON. THE CAM GUIDANCE LED BY THE
HRRR...00Z HRW-ARW2 AND 06Z NAM-CONEST SUGGEST A SIGNAL FOR AS
MUCH AS ADDITIONAL 2 INCHES OF RAIN THROUGH ABOUT 21Z. WHILE THE
HEAVIEST RAINS SHOULD TEND TO FOCUS MORE ON NORTH-CENTRAL TX AND
SOUTHERN OK...THERE WILL BE AN ALIGNMENT OF HEAVIER CONVECTIVE
RAINS ATTEMPTING TO LIFT UP TOWARD NORTHEAST OK THIS AFTERNOON IN
LINE WITH THE STRONGEST WARM ADVECTION AND UPPER LEVEL FORCING.
AREAS FARTHER EAST ACROSS WEST-CENTRAL AR WILL LIKELY STILL SEE
SOME ADDITIONAL RAIN AS WELL...BUT THE RAINFALL RATES SHOULD BE A
BIT LOWER AND WITH LESS CONVECTIVE ORGANIZATION AT LEAST OVER THE
NEXT SEVERAL HOURS.

NEVERTHELESS...GIVEN THE WET ANTECEDENT CONDITIONS ACROSS THE
REGION...RUNOFF AND FLASH FLOOD CONCERNS WILL REMAIN IN PLACE.

ORRISON

ATTN...WFO...FWD...LZK...OUN...SHV...TSA...

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

LAT...LON   36479489 36379382 36099288 35859230 35159150
            34249148 33769231 33789369 33759501 33709585
            33479654 33029729 32979802 33209857 33649880
            34359849 35029791 35719716 36249616