MESOSCALE PRECIPITATION DISCUSSION 0294
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
804 AM EDT FRI JUL 03 2015
 
AREAS AFFECTED...NERN TEXAS...SERN OKLAHOMA INTO ARKANSAS 
 
CONCERNING...HEAVY RAINFALL...FLASH FLOODING POSSIBLE 
 
VALID 031204Z - 031704Z
 
SUMMARY...FLASH FLOODING WILL BE POSSIBLE THROUGH 17Z ACROSS
PORTIONS OF NERN TEXAS...SERN OKLAHOMA INTO CNTRL/SRN ARKANSAS
WHERE INCREASING CONVECTIVE COVERAGE WITHIN UNIDIRECTIONAL FLOW
MAY LEAD TO POCKETS OF 3-5 INCHES OF RAINFALL.

DISCUSSION...AT 1145Z...WATER VAPOR IMAGERY AND VAD WIND PROFILE
PLOTS AT 700 MB SHOWED A SHORTWAVE TROUGH PRESSING SEWD ACROSS NRN
OKLAHOMA AND NRN ARKANSAS. RAP FORECAST SOUNDINGS AND GPS
PRECIPITABLE WATER PLOTS SHOWED PW VALUES OF 1.9 TO 2.2 INCHES AND
WET BULB ZERO HEIGHTS NEAR 14 KFT AGL ACROSS THE THREAT AREA WHICH
COULD SUPPORT RAINFALL RATES OF 2-3 IN/HR...SOME OF WHICH IS
ALREADY BEING OBSERVED ACCORDING TO DUAL POL RADAR ESTIMATES.
UNIDIRECTIONAL FLOW WITH LOW LEVEL FLOW EXCEEDING THE MEAN WIND IS
PRESENT THROUGHOUT THE REGION AND IS EXPECTED TO CONTINUE THROUGH
THE REMAINDER OF THE MORNING PER RECENT RAP FORECASTS.

ONGOING CLUSTERS OF HEAVY RAIN WITH TRAINING HAVE BEEN PERSISTING
ACROSS THE REGION FOR THE PAST FEW HOURS WITH THE MOST NOTABLE
REGENERATION POINTS ACROSS S-CNTRL OKLAHOMA AND W-CNTRL ARKANSAS.
FLOW IS QUITE DIFFLUENT ACROSS THE REGION AT THE MOMENT...BUT THIS
IS EXPECTED TO RELAX A BIT GOING INTO THE LATE MORNING HOURS.
HOWEVER...AS THE AFOREMENTIONED SHORTWAVE CONTINUES TO ADVANCE
SEWD THROUGH 17Z...EXPANDING COVERAGE OF RAINFALL IS EXPECTED TO
OCCUR FROM NEAR THE RED RIVER INTO CNTRL AND SRN ARKANSAS WITH
HOURLY RATES OF 2-3 IN/HR WITH THE ONSET OF DAYTIME HEATING. 

A HI-RES MODEL QPF CONSENSUS OF THE MOST RECENT GUIDANCE SHOWED AN
AXIS OF VERY HEAVY RAINFALL THROUGH 17Z ACROSS SERN OKLAHOMA INTO
CNTRL ARKANSAS WITH AMOUNTS OF 4-8 INCHES. WHILE THE UPPER RANGE
OF THESE VALUES COULD BE OVERDONE AND ALTHOUGH RECENT RUNS OF THE
HRRR HAVE BACKED OFF SOME ON QPF AMOUNTS...FEEL THE THREAT IS
STILL HIGH ENOUGH TO WARRANT CONCERN OF FLASH FLOODING GIVEN FFG
VALUES OF 2-3 IN/HR AND 3-4 INCHES IN 3 HOURS.

OTTO

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

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

LAT...LON   35049394 35029228 34999101 34799027 34429014 
            34139039 33849118 33689242 33509380 33489569 
            33939740 34659748 34899596