Graphic for MPD #0019
 
MESOSCALE PRECIPITATION DISCUSSION 0019
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
712 PM EST SUN JAN 15 2017
 
AREAS AFFECTED...CENTRAL TX...NORTH TX 
 
CONCERNING...HEAVY RAINFALL...FLASH FLOODING POSSIBLE 
 
VALID 160011Z - 160526Z
 
SUMMARY...TWO ROUNDS OF CONVECTION IN RAPID SUCCESSION WITHIN AN
INCREASINGLY EFFICIENT HEAVY RAIN ENVIRONMENT MAY CAUSE FLASH
FLOODING IN URBAN OR OTHER PARTICULARLY SENSITIVE AREAS.

DISCUSSION...THE ENVIRONMENT WAS PERHAPS FOREMOST A SEVERE WEATHER
ENVIRONMENT...BUT THE FLASH FLOOD POTENTIAL SHOULD NOT BE
UNDERESTIMATED AS SOUTH TO NORTH TRAINING BANDS OF CONVECTION WILL
BE QUICKLY FOLLOWED BY A QUASI-LINEAR SYSTEM. LATE AFTERNOON HRRR
RUNS HAD BEEN CONSISTENT AT PRODUCING ISOLATED TOTALS BETWEEN 2
AND 3 INCHES STRADDLING THE WARM FRONT / INTERSTATE 35 CORRIDOR
THROUGH 05Z. AT 00Z...THE INITIAL STORMS WERE TRAINING FROM ABOUT
190 DEGREES...FOLLOWING THE MEAN LOWER TO MID LEVEL WINDS...AS
BROAD SCALE LIFT INCREASED AHEAD OF THE EJECTING NEGATIVELY TILTED
MID LEVEL WAVE. THERE WAS A CORRESPONDING SUBTLE BACKING OF LOW
LEVEL FLOW OBSERVED PER RAP SOUNDINGS AND VAD WIND PROFILES FROM
FWS/GRK CONTRIBUTING TO THE TRAINING CELL MOTIONS.

OF PARTICULAR CONCERN...ONE-HOUR RAINFALL ESTIMATES FROM KFWS HAD
INCREASED ABOVE 2 INCHES WEST OF WACO AND HILLSBORO. THIS WAS
FAIRLY CLOSE TO THE RADAR AND AWAY FROM MELTING LAYER
ISSUES...SUCH THAT THERE IS LITTLE REASON TO DOUBT THE ESTIMATES.
PW VALUES WERE INCREASING TOWARD 1.4 INCHES IN THIS REGION AND
OTHER FACTORS SUCH AS INCREASING DEEP LAYER ASCENT AND LOW LEVEL
MOISTURE FLUX WILL FAVOR EFFICIENT RAINFALL PRODUCTION DESPITE
SOME SMALL HAIL.

FLASH FLOOD GUIDANCE VALUES ARE SOMEWHAT HIGH...BUT GIVEN THE
RECENT RADAR QPE TRENDS THE 3-HOUR FFG VALUES MAY BE EXCEEDED
WHEREVER THE S-N BANDS SET UP IN ADVANCE OF THE SQUALL LINE. WITH
THE WARM FRONT ALSO BISECTING THE DALLAS / FORT WORTH
METROPLEX...URBAN RUNOFF ISSUES MAY BECOME A FACTOR AS WELL.

BURKE

ATTN...WFO...EWX...FWD...SHV...

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

LAT...LON   33639601 33039511 32239591 30809737 30569831 
            31959817 32839829 33599781 


Last Updated: 712 PM EST SUN JAN 15 2017