Flash Flood Guidance
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000
AWUS01 KWNH 300731
FFGMPD
TXZ000-OKZ000-301145-

MESOSCALE PRECIPITATION DISCUSSION 0157
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
330 AM EDT SAT MAY 30 2015

AREAS AFFECTED...NORTHERN TX

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

VALID 300725Z - 301145Z

SUMMARY...INTENSE RAINFALL RATES WITH VERY SLOW-MOVING
THUNDERSTORMS WILL CONTINUE THROUGH DAWN. FLASH FLOODING WILL
REMAIN POSSIBLE.

DISCUSSION...RADAR AND SATELLITE IMAGERY CONTINUE TO SHOW A
FORWARD PROPAGATING MCS MOVING THROUGH WEST-CENTRAL TX...WITH NOW
A RATHER WELL-DEFINED MCV SIGNATURE SEEN IN RADAR IMAGERY JUST
NORTHWEST OF KDYS. THE COMMA-HEAD OF THE MCS IS WHERE SOME OF THE
MOST INTENSE CONVECTION AND HEAVIEST RAINFALL RATES ARE
SITUATED...ALONG WITH AN EASTWARD EXTENSION OF CONVECTION ALONG
THE NORTH SIDE OF A FRONTAL ZONE. SURFACE OBSERVATIONS SUGGEST
EVIDENCE OF A WEAK WAVE OF LOW PRESSURE NOW MOVING ALONG THE
BOUNDARY...AND CONVECTION HAS BEEN TENDING TO DEVELOP DOWNWIND TO
THE NORTH OF THE BOUNDARY IN LIEU OF AN UPTICK IN WARM ADVECTION
AHEAD OF THE MCV AND SURFACE WAVE.

THE CONVECTION IS BEING AIDED BY A FAIRLY STRONG INSTABILITY
GRADIENT ACROSS NORTH-CENTRAL TX. THE LATEST RAP ANALYSIS SHOWS A
NOSE OF 2000 TO 3000 J/KG OF MUCAPE OUT AHEAD OF THE BOW PORTION
OF THE MCS... AND SOME OF THIS ENERGY WILL CONTINUE TO FEED NORTH
AHEAD OF THE MCV AND INTO THE FRONTAL ZONE.

THE BOW PORTION OF THE MCS SHOULD CONTINUE TO PROPAGATE
SOUTHEASTWARD EARLY THIS MORNING...AND WHILE LOCALLY INTENSE
RAINFALL RATES WILL BE POSSIBLE WITH THIS...THE STRONGER CONCERN
FOR EXCESSIVE RAINFALL RATES WILL BE FARTHER NORTH NEAR THE TRACK
OF THE AFOREMENTIONED MCV COMMA-HEAD AND JUST NORTH OF THE FRONTAL
ZONE WHERE THE INSTABILITY GRADIENT WILL BE THE SHARPEST. THE 00Z
ARW AND 00Z NAM-CONEST OVER THE NEXT FEW HOURS SUGGEST RAINFALL
AMOUNTS OF AS MUCH AS 2 TO 3 INCHES WITH LOCALLY HEAVIER AMOUNTS
COURTESY OF THE LOCALLY VERY SLOW CELL MOTION AND CELL TRAINING.

THIS WILL FOSTER THE RISK OF FLASH FLOODING THROUGH DAWN.

ORRISON

...PLEASE SEE WWW.WPC.NCEP.NOAA.GOV FOR GRAPHIC PRODUCT...

ATTN...WFO...FWD...LUB...OUN...SHV...SJT...

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

LAT...LON   33829814 33799707 33589570 33249490 32749467
            32289508 32069629 32029747 32099896 32249969
            32770010 33379979 33719907


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