MESOSCALE PRECIPITATION DISCUSSION 0259
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
1231 AM EDT MON SEP 16 2013
 
AREAS AFFECTED...SRN AND CNTRL NM 
 
CONCERNING...HEAVY RAINFALL...FLASH FLOODING POSSIBLE 
 
VALID 160430Z - 160730Z
 
SUMMARY...UPPER LEVEL SUPPORT WILL SUSTAIN SLOW MOVING
THUNDERSTORMS THROUGH 07Z. RAIN TOTALS AT ANY ON SPOT MAY NOT
EXCEED 1 OR 1.5 INCHES...BUT THE VOLUME OF RAIN INTO ANY
PARTICULAR DRAINAGE BASIN COULD EASILY LEAD TO NEW FLASH FLOODING.

DISCUSSION...JUDGING BY RADAR AND SFC OBS AN OUTFLOW BOUNDARY HAD
STALLED OR WAS VERY SLOW MOVING IN GRANT...SIERRA...AND SOCCORRO
COUNTIES AT 04Z. THIS BOUNDARY WAS LOCATED AT THE NORTHWEST SIDE
OF A CAPE MAXIMUM...WITH UNSTABLE AIR FEEDING INTO SW AND CNTRL NM
IN A LAYER CENTERED ON 700 MB. THIS COMBINED WITH SUBTLE MID LEVEL
LIFT AT THE BASE OF THE SLOW MOVING INTERMOUNTAIN TROUGH...SHOULD
SUSTAIN THUNDERSTORMS THROUGH AT LEAST 07Z. AFTER THAT TIME...CAPE
DIMINISHES IN BOTH THE HRRR AND RAP MODELS.

WITH 0-6 KM WIND SHEAR ONLY 10-15 KT...CELLS WERE BEHAVING AS
ORDINARY CELLS WITH SHORT DURATION OF UPDRAFTS OVER ANY PARTICULAR
POINT. WITH SLOW MOVEMENT AVERAGING 5 KT...HOWEVER...LOCALLY HEAVY
RAIN COULD RESULT...ESPECIALLY IN A BASIN-AVERAGE SENSE. WITH MOST
OF THE CELLS AT LONG RANGE FROM RADAR...RAIN ESTIMATES WILL BE
DIFFICULT. PW VALUES ARE NEAR OR JUST ABOVE 1 INCH...BUT THERE IS
RELATIVELY DRY AIR BENEATH CLOUD BASE PER EPZ RAOB AND RAP
SOUNDINGS. AFTER DISCUSSING WITH NESDIS...FEEL THAT THIS EVENT IS
BEST GAUGED BY ASSUMING MAX RAIN RATES ABOUT 1 INCH PER HOUR.
FLASH FLOOD GUIDANCE IN THE REGION IS ON THE ORDER OF 1 INCH IN AN
HOUR...AND AGAIN...WITH THE FORCING MECHANISMS PERSISTING OVER THE
SAME LOCATION...OR DRIFTING SLOWLY ESE...COULD SEE SOME HIGHER
TOTALS LOCALLY. BOTH THE NSSL WRF AND EMC WRF ARW...WHICH HANDLED
THINGS WELL THROUGH 03Z...PREDICT EVENT TOTALS OVER 2 INCHES ALONG
THIS STALLED OUTFLOW BOUNDARY.

BURKE

ATTN...WFO...ABQ...EPZ...

ATTN...RFC...CBRFC...CNRFC...WGRFC...

LAT...LON   34410763 34890687 34900554 34120507 33540523 32610605
            32140712 32150827 32450873 33170863 34410763