MESOSCALE PRECIPITATION DISCUSSION 0594
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
453 PM EDT SAT JUL 29 2017

AREAS AFFECTED... TX PANHANDLE INTO NORTHWEST TX

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

VALID 292100Z - 300200Z

SUMMARY...SLOW MOVING CELLS FORMING IN   AXES OF STRONG
INSTABILITY AND DEEP MOISTURE COULD RESULT IN A FLASH FLOOD THREAT
INTO THE EARLY EVENING HOURS.  

DISCUSSION...CONVECTION IS FORMING IN AN AXIS OF 1500-2000 J/KG OF
MLCAPE FROM NEAR KDHT TO NORTH OF KDYS...AS THE LOW LEVEL CIN ON
THE AXIS IS IN THE PROCESS OF BECOMING ERODED. RAP MODEL SOUNDINGS
SHOWED THAT MUCH OF THE INSTABILITY IS STILL ELEVATED... NORTH OF
THE COLD FRONT MOVING INTO CENTRAL TX. THE STORMS ARE MOVING
SLOWLY TO THE NORTHWEST...ALONG WITH THE 10 KNOT 850-300 MB MEAN
WIND...NEAR THE AXIS OF THE MID LEVEL RIDGING.

THE CONVECTION IS FORMING ON A STRONG PRECIPITABLE WATER AXIS OVER
THIS AREA... WHERE VALUES RANGED BETWEEN 1.25 AND 1.50 INCHES. RAP
MODEL SOUNDINGS SHOWED DRY IN PLACE WITH THE DEVELOPING
STORMS...WHICH WOULD SUGGEST OUTFLOW DOMINATED CONVECTION
INITIALLY (AND SUPPORTED BY THE KLBB HCA PRODUCT).

HOWEVER...AS THE COLUMN MOISTENS...WARM RAIN PROCESSES COULD
BECOME MORE IMPORTANT.
HIGH RAINFALL RATES (NEAR 2.00 INCHES OVER DICKENS COUNTY BASED ON
THE KLBB RADAR) DUE TO THE SLOW MOTION OF THE CELLS COULD POSE A
LOCAL FLASH FLOOD THREAT INTO THE EARLY EVENING HOURS.

THE MOST RECENT HRRR SHOWED LOCAL 2.00 TO 3.00 INCH RAINFALL
AMOUNTS FROM KDUX SOUTH THROUGH KSWW...MAINLY BEFORE 01Z. GIVEN
THE SLOW MOTION OF THE CELLS...THESE RAINFALL AMOUNTS ARE
PLAUSIBLE. IN FACT...CELL MERGERS AND SHORT TERM TRAINING COULD
PRODUCE LOCAL 3.00+ INCH AMOUNTS NEAR THE AXIS OF INSTABILITY.

THE MITIGATING FACTOR FOR FLASH FLOODING COULD BE THE RELATIVELY
HIGH FLASH FLOOD GUIDANCE (GENERALLY GREATER THAN 2.00 INCHES).
BECAUSE OF THIS...FLASH FLOODING IS ONLY CONSIDERED POSSIBLE INTO
THE EARLY EVENING.

HAYES

ATTN...WFO...AMA...LUB...MAF...OUN...SJT...

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

LAT...LON   36170226 36100115 33329960 32469941 32270015
            34090187