MESOSCALE PRECIPITATION DISCUSSION 0237...CORRECTED
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
920 AM EDT THU SEP 12 2013
 
CORRECTED FOR TEXT

AREAS AFFECTED...CENTRAL TO NORTHERN CO...SOUTHEAST WY 
 
CONCERNING...HEAVY RAINFALL...FLASH FLOODING LIKELY 
 
VALID 121220Z - 121620Z
 
SUMMARY...THE SIGNIFICANT HEAVY RAIN/FLASH FLOODING EVENT IS
CONTINUING IN THE UPSLOPE AREAS IN THE LEE OF THE CENTRAL ROCKIES
FROM WEST OF DENVER INTERNATIONAL...INCLUDING DOWNTOWN
DENVER...NORTHWESTWARD TO THE WEST OF FORT COLLINS. LATEST RADAR
TRENDS ARE NOT SHOWING ANY SIGNIFICANT CHANGES TO THE AREAS OF
PRECIPITATION ACROSS THESE AREAS WITH THE POTENTIAL FOR ADDITIONAL
RUNOFF ISSUES HIGH.

DISCUSSION...THE ONGOING FLASH FLOOD EVENT CONTINUES ALONG THE
STATIONARY FRONTAL BOUNDARY DRAPED IN THE LEE OF THE CENTRAL
ROCKIES THROUGH EAST CENTRAL CO.  PW VALUES IN THE VICINITY OF
THIS BOUNDARY REMAIN WELL ABOVE AVERAGE AND ARE IN THE 99TH OR
GREATER PERCENTILE FOR OBSERVED PW VALUES IN SEPTEMBER. 
OVERALL...THERE IS NOT EXPECTED TO BE ANY SIGNIFICANT CHANGES TO
THE OVERALL PATTERN OVER EASTERN COLORADO...WITH CONTINUED LOW
LEVEL EASTERLY FLOW INTO THE FRONT AND THE UPSLOPE AREA OF THE CO
ROCKIES.   

THE HI RES ARW AND NMM FROM BOTH THE 0000 AND 0600 UTC RUNS
CONTINUE TO SHOW HEAVY RAINFALL AMOUNTS IN THIS UPSLOPE REGION
INTO EARLY THIS AFTERNOON...WITH ADDITIONAL 6 HOURS AMOUNTS IN
EXCESS OF 2".  THESE AMOUNTS SEEM REASONABLE GIVEN THE EXPECTED
PERSISTENT FAVORABLE PATTERN FOR HEAVY RAINS AND MAY BE UNDERDONE
LOCALLY.  MODEL SOUNDING DATA IN THIS AREA FROM THE LATEST RAP
CONTINUES TO SHOW A MOIST ADIABATIC LAYER FROM THE SURFACE UP TO
NEARLY 600 MB...WITH TEMPERATURES ABOVE ZERO THROUGH THIS LAYER. 

ADDITIONAL RAINFALL AMOUNTS OF .50-1" IN AN HOUR AND TOTALS OF
2-4"+ OVER A THREE TO SIX HOUR TIME FRAME POSSIBLE IN AREAS OF
PERSISTENT PRECIPITATION.


ORAVEC

ATTN...WFO...PUB...BOU...CYS...

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

LAT...LON   41670499 41330476 40780452 40140452 39630458 39210435
            38690421 38430435 38230484 38340526 39180545 39990560
            40780576 41290583 41590553 41720518 41670499