MESOSCALE PRECIPITATION DISCUSSION 0244
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
1152 PM EDT THU SEP 12 2013
 
AREAS AFFECTED...ERN CO...WRN KS...SW NE...SE WY 
 
CONCERNING...HEAVY RAINFALL...FLASH FLOODING LIKELY 
 
VALID 130351Z - 130851Z
 
SUMMARY...BROAD MODERATE RAIN AND LOCALLY HEAVIER CORES WILL
CONTINUE OVERNIGHT. WITH TIME EMPHASIS MAY SHIFT AWAY FROM CENTRAL
CO/WESTERN KS...THE INTERSTATE 70 CORRIDOR...AND TOWARD AREAS
FARTHER NORTH. RAIN RATES WILL AVERAGE 1 TO 1.25 INCHES PER HOUR
IN THE STRONGEST CORES.

DISCUSSION...GENTLE BUT SUSTAINED LIFTING OF A WARM/WET AND WEAKLY
UNSTABLE ENVIRONMENT WILL CONTINUE TO FAVOR MODERATE TO HEAVY
RAINS THROUGH MORNING. DUAL POL RADAR ESTIMATES HAD PERFORMED WELL
IN THIS ENVIRONMENT...AND AT 0330Z INDICATED RAIN RATES OF 1 TO
1.25 INCHES IN THE STRONGER CORES. ACTIVITY WAS BEST ORGANIZED
EAST TO WEST ALONG INTERSTATE 70 FROM GOODLAND TO DENVER. ANOTHER
WING OF ORGANIZED RAIN EXTENDED NORTH THROUGH THE FOOTHILLS WEST
OF BOULDER AND THROUGH ESTES PARK. 

THE ACTIVITY WAS BEING FED BY UPGLIDE AT THE 305 AND 310 K
ISENTROPIC SURFACES. THE NAM FORECASTS UPGLIDE TO BECOME FOCUSED
FARTHER NORTH WITH TIME...BEYOND ABOUT 06 OR 07Z. THIS OCCURS AS A
MID LEVEL WAVE FINALLY ROTATES AROUND THE GREAT BASIN LOW TO CAUSE
HEIGHT FALLS UP INTO WYOMING...AND A NORTHWARD SHIFT OF THE
PERSISTENT UPPER LEVEL DIFFLUENCE AXIS THAT HAS BEEN STUCK OVER
CO/KS. NUMEROUS HIGH RESOLUTION MODELS FORECAST HEAVY RAIN TO
DEVELOP TOWARD THE PLAINS OF NE CO/SW NE/SE WY AS THIS OCCURS
LATER TONIGHT. AT THE SAME TIME...UPGLIDE AND UPSLOPE FLOW REMAINS
PERSISTENT ENOUGH TO SUGGEST CONTINUED RAIN IN THE FOOTHILLS NORTH
OF DENVER. ALTHOUGH NOT HAS HEAVY AS THE CORES OUT ON THE EASTERN
PLAINS...THIS RAIN WILL UNDOUBTEDLY EXACERBATE ONGOING FLOODING IN
THAT AREA. ADDITIONAL RAIN TOTALS COULD AVERAGE 1-3 INCHES IN THE
FOOTHILLS BEFORE THE MID LEVEL WAVE PASSES...BY 09 OR 10Z
ACCORDING TO THE RAP.

GREATER UNCERTAINTY LIES TO THE EAST...WHERE THE ESTABLISHED LOW
LEVEL CONVERGENCE NEAR I-70 MAY CAUSE HEAVY RAIN TO LINGER WHERE
IT WAS AT 0330Z...FOR A WHILE LONGER THAN THE MODELS SUGGEST. BUT
AS THE MID LEVEL WAVE TAKES ITS SUPPORT FARTHER NORTH WITH
TIME...WE SHOULD SEE THE I-70 ACTIVITY DISSIPATE AND REDEVELOP
NORTHWARD. INSTABILITY WILL BE LESS TO THE NORTH...BUT RAIN RATES
OF NEAR 1"/HR WOULD STILL BE EXPECTED.

BURKE

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

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

LAT...LON   39210578 38150515 37630393 37260276 37540155 38360039
            38879992 39419967 40179996 41060129 41480228 41810411
            41390567 40540591 39210578