MESOSCALE PRECIPITATION DISCUSSION 0256
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
1123 AM EDT SUN SEP 15 2013
 
AREAS AFFECTED......EASTERN CO/SOUTHEASTERN WY/WESTERN KS... 
 
CONCERNING...HEAVY RAINFALL...FLASH FLOODING POSSIBLE 
 
VALID 151522Z - 152022Z
 
SUMMARY...WITH THE COLD FRONT SINKING SOUTH AND EAST OF THE
CENTRAL ROCKIES...THE LOW-LEVEL FLOW SHOULD CONTINUE TO VEER
AIDING IN ENHANCED UPSLOPE WINDS THROUGHOUT THE DAY. ANTECEDENT
CONDITIONS CONTINUE TO INDICATE THE REGION OF INTEREST WILL BE
PRONE FOR FLASH FLOODING EVENTS.

DISCUSSION...THE 12Z SOUNDING FROM DNR WAS NEARLY SATURATED FROM
THE SURFACE UP TO APPROXIMATELY 600 MB. PWATS AT JUST ABOVE AN
INCH RANK WITHIN THE 95TH TO 99TH PERCENTILES FOR MID-SEPTEMBER
CLIMATOLOGY. DESPITE THE TIME OF DAY NOT BEING FAVORABLE FOR
SURFACE-BASED CONVECTION...THIS SOUNDING HAD A VERY LOW LEVEL OF
FREE CONVECTION WITH OBSERVED CAPE VALUES OF NEARLY 700 J/KG. IT
APPEARS THE ATMOSPHERE HAS ALREADY BEGUN TAPPING INTO THIS AXIS OF
INSTABILITY GIVEN MULTIPLE AREAS OF ENHANCED CU SHOWING UP ON THE
VIS SATELLITE THIS MORNING. SOME OF THE COOLER CLOUD TOPS ARE
ACROSS NORTHEASTERN CO WHICH SEEMS TO BE COLLOCATED WITH THE
LEADING EDGE OF A THETA-E GRADIENT BASED ON THE 14Z RAP.

LOOKING FORWARD...THE BOUNDARY LAYER TO 700 MB WINDS SHOULD
CONTINUE TO VEER MORE TOWARD THE EAST TO NORTHEASTERLY DIRECTION
WHICH WILL ENHANCE THE UPSLOPE FLOW. CONDITIONS ALOFT APPEAR
FAVORABLE AS THE CENTRAL ROCKIES/CENTRAL HIGH PLAINS HAVE
SUFFICIENT DIFFLUENCE ALOFT AHEAD OF AN APPROACHING SHORTWAVE. THE
MOST RECENT HIGH-RES GUIDANCE SHOW PRETTY STRONG CLUSTERING OF
HIGHER RAINFALL AMOUNTS STRETCHING ALONG THE COLORADO ROCKIES
EASTWARD ALONG AND NORTH OF I-70. SOME OF THE MORE AGGRESSIVE
MODELS INCLUDE THE 00Z HIGH-RES ARW AND NMM...WRF NSSL...AND
EXPERIMENTAL NAM CONEST.


RUBIN-OSTER

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

ATTN...RFC...ABRFC...CBRFC...MBRFC...

LAT...LON   40930601 41550536 41620418 41090326 40620223 40240139
            39590009 38880043 38560213 37800390 38190545 39290604
            40930601