MESOSCALE PRECIPITATION DISCUSSION 0018
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
1222 AM EST SUN JAN 15 2017
 
AREAS AFFECTED...FAR WEST TX AND FAR SOUTHEAST NM 
 
CONCERNING...HEAVY RAINFALL...FLASH FLOODING POSSIBLE 
 
VALID 150520Z - 150920Z
 
SUMMARY...CONVECTION FORMING ALONG THE RIO GRANDE RIVER COULD
RESULT IN TRAINING... POSING A FLASH FLOOD THREAT INTO THE EARLY
MORNING HOURS. 

DISCUSSION...IR IMAGES SHOWED COOLING CLOUD TOPS ALONG THE RIO
GRANDE RIVER SOUTH OF KMRF...AND LIGHTNING DATA HAS SHOWN A STEADY
INCREASE IN COVERAGE FROM SOUTH OF THE RIVER INTO FAR SOUTHWEST
TX. MUCH OF THE ACTIVITY IS BEYOND SIGNIFICANT RADAR
COVERAGE...BUT THE MRMS PRECIPITATION RATE INFORMATION SHOWED
VALUES NEAR 1.25 INCHES CLOSE TO THE RIVER. 

THE ACTIVITY IS FORMING AND STRENGTHENING IN A LARGE AREA OF
500-1000 J/KG OF MUCAPE EXTENDING FROM NORTHERN MEXICO ACROSS FAR
WEST TX. FAVORABLE DYNAMICS (IN THE FORM OF INCREASING DIVERGENCE
AHEAD OF THE LONG WAVE TROUGH CROSSING NORTHERN MEXICO) WOULD
PROVIDE SUFFICIENT SYNOPTIC SCALE LIFT FOR CONTINUED CONVECTIVE
DEVELOPMENT. 

THUS FAR...MOISTURE HAS BEEN FAIRLY LIMITED...BUT THE LATEST RAP
SHOWED AN INCREASING LOW LEVEL SOUTHEAST INFLOW...WITH
PRECIPITABLE WATER VALUES NEARING AN INCH AFTER 05Z. UPSTREAM
PRECIPITABLE WATER VALUES TOP OUT NEAR 1.25 INCHES ACROSS SOUTH
TX. 

THE LIGHTNING DATA HAS SHOWN A SLOW EASTWARD DRIFT TO THE
CONVECTION...AND RAP CORFIDI VECTORS SHOW A SLOW EASTWARD DRIFT
WITH TIME. THIS WOULD TEND TO MITIGATE THE THREAT FOR
TRAINING...BUT AS THE LONG WAVE TROUGH STARTS TAKING ON A NEGATIVE
TILT... THE THREAT FOR TRAINING COULD INCREASE.

THERE IS A FAIR AMOUNT OF SPREAD IN THE HIGH RESOLUTION GUIDANCE
ON THE PLACEMENT OF THE HIGHEST RAINFALL AXIS...WITH THE LATEST
HRRR SHOWING THE POTENTIAL FOR LOCAL 1.50 INCH RAINFALL AMOUNTS IN
AREAS WHERE ONE HOUR FLASH FLOOD GUIDANCE NUMBERS ARE AS LOW AS
1.50 INCHES. TRAINING COULD BE REQUIRED FOR FLASH FLOODING TO
OCCUR...AND THIS IS SUGGESTED BY SOME OF THE HIGH RES GUIDANCE
(INCLUDING THE 00Z NSSL WRF AND 00Z SPC WRF). 

BECAUSE OF THE UNCERTAINTY CONCERNING THE THREAT OF
TRAINING...FLASH FLOODING IS ONLY CONSIDERED POSSIBLE AT THIS
TIME. 

HAYES

ATTN...WFO...MAF...

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

LAT...LON   32680358 32550300 31760279 31060279 30560282 
            29310311 29020338 29350403 29350404 29800463 
            30290478 31360472 32050442