Graphic for MPD #0401

MESOSCALE PRECIPITATION DISCUSSION 0401
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
647 PM EDT MON JUN 26 2017

AREAS AFFECTED...SOUTHEAST TX...SOUTHERN LA

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

VALID 262245Z - 270245Z

SUMMARY...SLOW-MOVING SHOWERS AND THUNDERSTORMS WILL CONTINUE TO
BE A THREAT OVER THE NEXT FEW HOURS.

DISCUSSION...THE PROXIMITY OF A OLD WEAK STATIONARY FRONT WITH AN
ABUNDANCE OF DIURNALLY ENHANCED INSTABILITY AND A RATHER DEEP
LAYER OF MOISTURE WILL CONTINUE TO FOSTER DEVELOPMENT OF SHOWERS
AND THUNDERSTORMS OVER THE NEXT FEW HOURS. SOME LOCALIZED
SEA-BREEZE AND MESOSCALE BOUNDARY FORCING IS EXPECTED TO FURTHER
CONCENTRATE THE CONVECTION ON A SMALLER SCALE.

PWATS OF 2 TO 2.2 INCHES WILL FAVOR HIGHLY EFFICIENT RAINFALL
PROCESSES...WHICH WILL CONTRIBUTE TO RAINFALL RATES UP TO 3
INCHES/HR LOCALLY. THE SLOW CELL MOTION COURTESY OF A WEAK MEAN
STEERING FLOW PATTERN WILL ADD TO THE RAINFALL POTENTIAL...WITH
LOCALIZED AMOUNTS UP TO 5 INCHES NOT OUT OF THE QUESTION. THIS IS
CONSISTENT WITH THE LATEST HRRR GUIDANCE.

CONDITIONS SHOULD IMPROVE LATER IN THE EVENING AS SURFACE
INSTABILITY BEGINS TO WANE...BUT THESE AMOUNTS ESPECIALLY NEAR
URBANIZED AREAS WILL CAUSE RUNOFF PROBLEMS AND POTENTIALLY SOME
FLASH FLOODING OVER THE NEXT FEW HOURS.

ORRISON

ATTN...WFO...CRP...EWX...HGX...LCH...LIX...

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

LAT...LON   30669433 30499247 29849083 29269053 29329113
            29519224 29669303 29439427 29029503 28479603
            28259659 28329711 29299697 30139619


Last Updated: 647 PM EDT MON JUN 26 2017