MESOSCALE PRECIPITATION DISCUSSION 0511
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
629 PM EDT WED SEP 23 2015
 
AREAS AFFECTED...EASTERN NM...PORTIONS OF NORTH TX 
 
CONCERNING...HEAVY RAINFALL...FLASH FLOODING POSSIBLE 
 
VALID 232230Z - 240330Z
 
SUMMARY...CONVECTION TAPPING INSTABILITY AND DEEP MOISTURE ON A
LOW LEVEL SOUTHERLY FLOW COULD PRODUCE LOCAL FLASH FLOODING
THROUGH THE EVENING HOURS.

DISCUSSION...CONVECTION IS INCREASING IN COVERAGE ACROSS EASTERN
NM AND A PORTION OF NORTH TX ALONG AN INSTABILITY AXIS (WITH
SBCAPES BETWEEN 1000-1500 J/KG). A 20 TO 25 KNOT LOW LEVEL
SOUTHERLY FLOW CONTINUES TO TRANSPORT 1.25 INCH PRECIPITABLE WATER
AIR (WHICH IS ABOUT TWO STANDARD DEVIATIONS ABOVE THE MEAN) INTO
FAR EASTERN NM AND NORTH TX. THE IR LOOPS SHOWED COOLING TOPS AND
KMAF RADAR INDICATED 1.50 TO 1.75 INCH PER HOUR RAINFALL RATES.
HOWEVER...GIVEN THE AMOUNT OF DRY AIR IN THE MID LEVELS...THESE
ESTIMATES ARE PROBABLY HAIL CONTAMINATED.

A SHORT WAVE APPROACHING FROM WESTERN NM PROVIDES INCREASING
SYNOPTIC SCALE LIFT...ALLOWING THE CONVECTION TO BECOME MORE
WIDESPREAD WITH TIME. THE LATEST HRRR AND 12Z WRF ARW/NMMB SHOWED
THE POTENTIAL FOR LOCAL 2 INCH RAINFALL AMOUNTS. AS THE MOISTURE
IN THE COLUMN INCREASES... THESE AMOUNTS SEEM PLAUSIBLE. ONE AND
THREE HOUR FLASH FLOOD GUIDANCE VALUES ARE AS LOW AS 1.00 TO 1.50
INCHES...SO FLASH FLOODING IS CONSIDERED POSSIBLE.

THE HIGH RESOLUTION MODEL CONSENSUS SUGGESTS THESE RAINFALL
AMOUNTS ARE MOST LIKELY TO OCCUR ACROSS FAR EASTERN NM AND NORTH
TX FROM KDHT TO KMAF THROUGH ABOUT 24/03Z. AS THE LOW LEVEL INFLOW
MOVES EAST AND INSTABILITY WEAKENS...THE THREAT FOR FLASH FLOODING
SHOULD WANE AFTER THAT TIME.

HAYES

ATTN...WFO...ABQ...AMA...LUB...MAF...PUB...

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

LAT...LON   37140383 36800290 34840210 32190212 32100413 
            34740431 36190493