MESOSCALE PRECIPITATION DISCUSSION 0459
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
105 AM EDT WED JUL 13 2016
 
AREAS AFFECTED...NORTHEAST CO 
 
CONCERNING...HEAVY RAINFALL...FLASH FLOODING POSSIBLE 
 
VALID 130505Z - 130905Z
 
SUMMARY...CONVECTION FORMING OVER NORTHEAST CO ON THE EDGE OF AN
INSTABILITY AXIS IS EXPECTED TO TRAIN OVER AREAS WITH RELATIVELY
LOW FLASH FLOOD GUIDANCE... RESULTING IN A FLASH FLOOD THREAT INTO
THE EARLY MORNING HOURS.

DISCUSSION...CONVECTION IS FORMING AND MOVING EASTWARD NEAR THE 40
NORTH PARALLEL THIS EVENING...AHEAD OF A WEAK SHORT WAVE OVER
NORTH CENTRAL CO (AS SEEN ON THE WATER VAPOR LOOP). THE CONVECTION
IS ON THE NORTHERN EDGE OF A 500-1000 J/KG MLCAPE GRADIENT...AND
THE LOW TO MID LEVEL FLOW IS EXPECTED TO CONTINUE FEEDING
INSTABILITY AND 1.00 TO 1.25 INCH PRECIPITABLE WATER AIR INTO THE
AXIS OF CONVECTION (PER THE LATEST RAP). THE KFTG RADAR HAS
ALREADY INDICATED HOURLY RAINFALL RATES NEAR AN INCH ACROSS
SOUTHEAST MORGAN...WASHINGTON AND YUMA COUNTIES IN CO. 

THE BEST AXIS OF INSTABILITY REMAINS IN PLACE THROUGH ABOUT 09Z.
AFTER THAT TIME...RAP SOUNDINGS AKO AND KIML SHOWED STRONG CAPPING
NEAR 700 MB...AND THIS IS EXPECTED TO BEGIN SHUTTING DOWN THE
SURFACE BASED CONVECTION (THOUGH ELEVATED CONVECTION IS STILL
POSSIBLE). THE 03Z HRRR/PARALLEL HRRR/00Z WRF ARW ALL SHOWED AN
AXIS OF LOCAL 2-4 INCH RAINFALL AMOUNTS...THOUGH ALL THREE MODELS
HAVE THE AXIS TOO FAR SOUTH BY ABOUT 40 MILES OR SO...BASED ON
CURRENT RADAR TRENDS). 

ONE AND THREE HOUR FLASH FLOOD GUIDANCE VALUES ARE AS LOW AS 1.00
TO 1.50 INCHES ACROSS PORTIONS OF WASHINGTON...KIT CARSON AND YUMA
COUNTIES. CONVECTION TRAINING OVER THESE AREAS COULD EASILY EXCEED
FLASH FLOOD GUIDANCE...SO A FLASH FLOOD THREAT WILL REMAIN IN
PLACE THROUGH ABOUT 09Z. 

HAYES

ATTN...WFO...BOU...CYS...GLD...LBF...

ATTN...RFC...MBRFC...

LAT...LON   41000329 40830202 39900189 39580210 39390336 
            39380368 39440417 39770471 40690447