MESOSCALE PRECIPITATION DISCUSSION 0038
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
751 AM EST SAT FEB 24 2018

AREAS AFFECTED...NORTH-CENTRAL TO NORTHEAST TX...SOUTH-CENTRAL TO
EASTERN OK...WESTERN AR

CONCERNING...HEAVY RAINFALL...FLASH FLOODING LIKELY

VALID 241250Z - 241800Z

SUMMARY...HEAVY SHOWERS AND THUNDERSTORMS SHOULD TEND TO INCREASE
IN COVERAGE AND ORGANIZATION OVER THE NEXT FEW HOURS. SENSITIVE
SOIL CONDITIONS WILL PROMOTE EXCESSIVE RUNOFF AND/OR FLASH
FLOODING.

DISCUSSION...THE MORNING GOES-16 RGB AIRMASS IMAGERY SHOWS A
FAIRLY WELL-DEFINED VORT CENTER LIFTING NORTHEAST ACROSS
WEST-CENTRAL TX EMBEDDED WITHIN LARGER SCALE SOUTHWEST FLOW
ASSOCIATED WITH THE SUBTROPICAL JET CROSSING THE SOUTHERN PLAINS.
MEANWHILE...THIS IS OUT AHEAD OF A STRONGER UPPER TROUGH ADVANCING
EAST ACROSS THE FOUR CORNERS REGION.

NUMEROUS SHOWERS AND THUNDERSTORMS ARE ALREADY BREAKING OUT ACROSS
NORTH-CENTRAL TX AND QUICKLY WORKING INTO SOUTHERN OK WHERE THE
ENERGY ALOFT IS WORKING IN TANDEM WITH THE NOSE OF A 40 TO 45 KT
S/SW LOW LEVEL JET THAT IS BOLSTERING THE WARM ADVECTION ALOFT
OVER TOP A STABLE BOUNDARY LAYER. ALREADY THERE IS A FAIR DEGREE
OF ELEVATED INSTABILITY WITH MUCAPE VALUES UPWARDS OF 1000 J/KG
POOLING UP ALONG THE RED RIVER AND CONVECTIVE UPDRAFTS BEING AIDED
BY 40 TO 50 KTS OF EFFECTIVE BULK SHEAR.

GRADUALLY INCREASING LARGE SCALE ASCENT AND IMPROVING
THERMODYNAMICS AHEAD OF THE APPROACHING LARGE SCALE TROUGH FROM
THE FOUR CORNERS REGION WILL ALLOW CONVECTION TO INCREASE IN
COVERAGE AND ORGANIZATION OVER THE NEXT FEW HOURS...AND CAPABLE OF
PRODUCING LOCALLY VERY HEAVY RAINFALL RATES GIVEN THE DEGREE OF
DEEPER LAYER MOISTURE TRANSPORT. CIRA-LPW DATA CONFIRMS A
WELL-DEFINED EASTERN TROPICAL PACIFIC CONNECTION OF 700/300 MB
MOISTURE WHICH IS CONTRIBUTING TO PWATS AS HIGH AS 1.5 INCHES JUST
SOUTH OF THE RED RIVER. THIS ENVIRONMENT WILL PROMOTE ENHANCED
RAINFALL RATES THAT MAY REACH 1.5 TO 2 INCHES/HR WITHIN STRONGER
CONVECTIVE CORES.

MOST OF THE CAM GUIDANCE ALREADY APPEARS TO BE TOO SLOW WITH THE
ONGOING CONVECTIVE INITIATION AND RADAR IMAGERY SHOWS THE ACTIVITY
ORGANIZING A BIT WEST OF THE CAM CONSENSUS. THEY COLLECTIVELY
SUGGEST ADDITIONAL AMOUNTS OF 1 TO 1.5 INCHES THROUGH 18Z OVER
ESPECIALLY SOUTH-CENTRAL TO EASTERN OK...BUT THE DEGREE OF
ELEVATED INSTABILITY...EFFICIENT MOISTURE TRANSPORT AND LARGE
SCALE ASCENT FAVORS AMOUNTS THAT COULD BE HIGHER AND PERHAPS
LOCALLY AS MUCH AS 2 TO 3 INCHES. IT IS LIKELY TOO THAT CONVECTION
WILL MAKE IT INTO WESTERN AR FASTER THAN THE CAM GUIDANCE IS
SUGGESTING BASED ON THE LATEST SATELLITE AND RADAR TRENDS.

GIVEN THE RECENT RAINFALL OVER THE LAST COUPLE OF DAYS...THE SOIL
CONDITIONS ARE HIGHLY SENSITIVE AND THESE ADDITIONAL AMOUNTS
THROUGH MIDDAY WILL LIKELY CAUSE ENHANCED RUNOFF AND CONCERNS FOR
FLASH FLOODING. WILL CONTINUE TO MONITOR.

ORRISON

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

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

LAT...LON   36589540 36489445 35909328 34619310 33689399
            33099507 32789590 32469681 32409789 32939896
            33539925 34189940 35049878 35759783 36029727
            36389635