MESOSCALE PRECIPITATION DISCUSSION 0128
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
554 PM EDT MON MAY 25 2015
 
AREAS AFFECTED...EASTERN OK...EASTERN TX...NORTHWEST LA...WESTERN
AND CENTRAL AR 
 
CONCERNING...HEAVY RAINFALL...FLASH FLOODING LIKELY 
 
VALID 252145Z - 260115Z
 
SUMMARY...STRONG MCS TO CONTINUE EAST AND FAVOR SIGNIFICANT
RAINFALL POTENTIAL WITH FLASH FLOODING LIKELY THIS EVENING.

DISCUSSION...A STRONG AND WELL-ORGANIZED MCS IS MOVING EAST EARLY
THIS EVENING ACROSS SOUTHEAST OK AND EASTERN TX. THE CONVECTION IS
VERY COLD-TOPPED IN NATURE AND EXHIBITING A NUMBER OF EMBEDDED
OVERSHOOTING TOPS AS PER THE GOES-OTD ALGORITHM.

THE LATEST GOES-14 SRSO 1-MIN IMAGERY SUGGESTS AN UNCAPPED AND
VERY UNSTABLE AIRMASS AHEAD OF THE MCS WITH A LARGE CU/TCU FIELD
INDICATED IN ASSOCIATION WITH A PERSISTENT MOIST SOUTHERLY LOW
LEVEL FETCH IN OFF THE WESTERN GULF OF MEXICO. THE LATEST RAP
ANALYSIS SUGGESTS SBCAPE VALUES AHEAD OF THE MCS REACHING 4000 TO
4500 J/KG AND COUPLED WITH PWATS OF 1.5 TO 1.75 INCHES AS PER
GOES-SOUNDER DATA.

MEANWHILE...THE LATEST GOES-RGB AIRMASS IMAGERY SHOWS A
WELL-DEFINED AND COMPACT SHORTWAVE LIFTING NORTHEAST ACROSS
NORTHWEST TX LATE THIS AFTERNOON AND OVER THE NEXT FEW HOURS THIS
WILL ADVANCE NORTHEAST THROUGH CENTRAL OK. THE WIND FIELD ALOFT
OVER MUCH OF SOUTHEAST OK AND EASTERN TX IS HIGHLY DIVERGENT WHICH
IS WELL DEPICTED IN WV IMAGERY. THIS IS FOSTERING STRONG DEEPER
LAYER ASCENT OVER THE STRONG THERMODYNAMIC ENVIRONMENT IN VICINITY
OF THE MCS AND AHEAD OF IT.

EXPECT THE MCS TO CONTINUE TO MAINTAIN ITS CURRENT LEVEL OF
STRENGTH INTO THE EVENING HOURS. THE NORTHERN PORTION OF THE LINE
SHOULD TEND TO BE FAIRLY PROGRESSIVE AND WILL REACH INTO WESTERN
AR BY 23Z...BUT GIVEN SUCH HEAVY RAINFALL OF LATE...AND INTENSE
RAINFALL RATES OF UP TO 2 INCHES/HR...THERE WILL STILL BE STRONG
CONCERNS FOR FLASH FLOODING. THE SOUTHERN PORTION OF THE LINE FROM
JUST NORTH OF KSAT TO KAUS IS TENDING TO PROPAGATE A BIT SLOWER TO
THE EAST...AND THERE HAVE BEEN SEVERAL CELL MERGERS OCCURRING
WITHIN THIS PART OF THE LINE. MULTIPLE RUNS OF THE HRRR OF LATE
HAVE SUGGESTED THIS PART OF THE LINE TAKING ON MORE OF A SW/NE
ORIENTATION THIS EVENING WHICH GIVEN THE SW MEAN LAYER FLOW WILL
FAVOR CELL-TRAINING. WILL NEED TO MONITOR THIS CLOSELY AS THIS
WOULD GREATLY ENHANCE THE FLASH FLOOD CONCERNS FOR SOUTHEAST TX.

ORRISON

ATTN...WFO...CRP...EWX...FWD...HGX...LCH...LZK...OUN...SHV...

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

LAT...LON   36259414 35969287 34949226 33439233 31549304 
            29969405 29239490 28709613 28879758 29459840 
            30349775 31139677 31859611 32669561 33319549 
            34129549 34929580 35379684 36079571