MESOSCALE PRECIPITATION DISCUSSION 0309
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
330 PM EDT FRI AUG 22 2014
 
AREAS AFFECTED...NERN COLORADO INTO SWRN NEBRASKA AND EXTREME NWRN
KANSAS 
 
CONCERNING...HEAVY RAINFALL...FLASH FLOODING POSSIBLE 
 
VALID 221928Z - 230100Z
 
SUMMARY...SLOW MOVING AND TRAINING CONVECTION IS EXPECTED TO
ORGANIZE BY 20-21Z...LEADING TO A FLASH FLOOD THREAT OVER NERN
COLORADO. RAINFALL RATES OF 1-2 IN/HR WITH 3-4 INCHES TOTAL WILL
BE POSSIBLE BY 01Z.

DISCUSSION...AT 19Z...SURFACE OBSERVATIONS PLACED A 1016 MB HIGH
BETWEEN AKO AND APA...WHILE LOW PRESSURE WAS SITUATED ALONG THE
SRN COLORADO/KANSAS BORDER. LOW LEVEL FLOW WAS FUNNELING IN
BETWEEN THESE TWO FEATURES...MOST NOTED BY STEADY 20 KTS AT 850 MB
PER THE KGLD VAD WIND PROFILE. THIS UPSLOPE COMPONENT WAS KEEPING
DEWPOINTS IN THE 55 TO 60 F RANGE ACROSS MUCH OF ERN COLORADO WITH
BREAKS IN CLOUDS NOTED ON VISIBLE IMAGERY ALLOWING WEAK
INSTABILITY TO DEVELOP. 

THE SURFACE LOW OVER THE COLORADO/KANSAS BORDER IS FORECAST TO
SLOWLY LIFT NNE THIS EVENING WHILE INSTABILITY CONTINUES TO
DEVELOP ALLOWING CONVECTION TO INCREASE IN COVERAGE...WITH SOME
TCU ALREADY NOTED ON 1-MIN RESOLUTION GOES-14 SRSO IMAGERY.
TRAINING OF RAINFALL WAS NOTED EARLIER BETWEEN FORT MORGAN AND
STERLING IN THE VICINITY OF I-76 AND FLASH FLOOD GUIDANCE VALUES
ARE ALREADY 1-2 INCHES IN 3 HOURS FOR MUCH OF THE THREAT AREA. 

AS UPPER DIFFLUENCE AND THE RIGHT ENTRANCE REGION OF AN UPPER
LEVEL JET STREAK...TIED TO AN UPPER LEVEL LOW CURRENTLY OVER THE
FOUR CORNERS REGION...MOVES OVER THE AREA...LIFT SHOULD BE
ENHANCED WITH RAINFALL RATES OF 1-2 IN/HR EXPECTED. GIVEN THE
POTENTIAL FOR TRAINING...AS NOTED WITH EARLIER RAINFALL...FLASH
FLOODING WILL BE A GROWING CONCERN THROUGH THE REMAINDER OF THE
AFTERNOON INTO THE EVENING. A VAST MAJORITY OF HI-RES MODEL QPF
AGREES ON THIS IDEA BUT THERE ARE SOME DIFFERENCES IN
TIMING/PLACEMENT...HOWEVER...CONFIDENCE IS ABOVE AVERAGE FOR
CONVECTIVE DEVELOPMENT BY 00Z ACROSS THE THREAT AREA.

OTTO

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

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

LAT...LON   38930379 38620510 39030549 39790541 40520470 41330335
            41440180 41260077 40750047 40330054 39840109 39420209
            38930379