MESOSCALE PRECIPITATION DISCUSSION 0247
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
1023 AM EDT FRI SEP 13 2013
 
AREAS AFFECTED...EASTERN CO/WESTERN KS/SOUTHWESTERN NE... 
 
CONCERNING...HEAVY RAINFALL...FLASH FLOODING POSSIBLE 
 
VALID 131422Z - 131922Z
 
SUMMARY...A REPRIEVE FROM THE HEAVY RAINFALL IS EVIDENT ALTHOUGH
RESIDUAL ISSUES MAY CONTINUE ONCE THE ATMOSHPERE BEGINS TO
DESTABILIZE BY THE AFTERNOON. FLASH FLOOD GUIDANCE REMAINS
EXTREMELY LOW OVER THE ENCOMPASSED AREA WHICH COULD LEAD TO FLASH
FLOODING CONDITIONS WITH VERY LITTLE PRECIPITATION.

DISCUSSION...A HISTORIC FLASH FLOODING EVENT FOR AREAS OF THE
CENTRAL ROCKIES CONTINUES AS RECORD PWAT VALUES INVADE THE REGION
FROM THE TROPICAL PACIFIC. THE 12Z PWAT PERCENTILE PLOT SUGGESTS
AN EXPANSIVE REGION OF 99TH PERCENTILE VALUES EXTENDING FROM EL
PASO TX UP ALONG THE SPINE OF THE SOUTHERN/CENTRAL ROCKIES. AS
EXPECTED...THE 12Z DNR SOUNDING INDICATED A SATURATED ATMOSPHERE
FROM THE BOUNDARY LAYER UP TO NEAR 500 MB WITH A WARM CLOUD LAYER
EXTENDING ALMOST 10,000 FEET ABOVE THE GROUND. AT THIS
TIME...REGIONS CLOSER TO THE COLORADO ROCKIES APPEAR TO HAVE
LOW-LEVEL WINDS WHICH PARALLEL THE TERRAIN WHICH HAS SIGNIFICANTLY
REDUCED THE UPSLOPE COMPONENT OF THE WIND. FARTHER EAST CLOSER TO
THE CO/KS BORDER...THE WIND PROFILES ARE MUCH STRONGER WITH THE
FLOW INCREASING TO ALMOST 30 KTS AT 850-MB BY 16Z ONWARD.
ADDITIONALLY...THE FLOW WILL CONTAIN MORE OF AN EASTERLY COMPONENT
WHICH SHOULD BE ABLE TO ADVECT THE HIGHER MOISTURE CONTENT OVER
THE GREAT PLAINS.

TOWARD THE END OF THE DURATION OF THIS MESOSCALE DISCUSSION...THE
13Z RAP AND 10Z HRRR SHOW A CORRIDOR OF INCREASING INSTABILITY
WITH MUCAPE VALUES RANGING FROM 1000 TO 2000 J/KG ACROSS EASTERN
CO/WESTERN KS. THE 06Z HIGH-RES NMM AND 00Z SPC WRF SEEM TO AGREE
AS THEY PRODUCE HEAVY PRECIPITATION IN THIS REGION...PARTICULARLY
IN THE 14-18Z TIMEFRAME. OF COURSE ANY ADDITIONAL HEAVY RAIN WOULD
CAUSE ISSUES GIVEN MANY LOCATIONS HAVE SEEN WELL OVER A HALF A
FOOT OF RAINFALL THE PAST 48 HOURS.



RUBIN-OSTER

ATTN...WFO...ICT...GID...DDC...GLD...PUB...BOU...

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

LAT...LON   40380605 40890553 40980414 40570305 39960185 39799915
            38529875 38329940 38420113 38210264 37760362 37640464
            37980577 39310605 40380605