MESOSCALE PRECIPITATION DISCUSSION 0044
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
911 PM EDT SAT MAY 18 2013
 
AREAS AFFECTED...CENTRAL/EASTERN KS AND NORTHERN OK 
 
CONCERNING...HEAVY RAINFALL...FLASH FLOODING POSSIBLE 
 
VALID 190100Z - 190600Z
 
SUMMARY...UPSCALE GROWTH OF AN MCS AND A BROAD LOW LEVEL JET ARE
EXPECTED TO YIELD WIDESPREAD MODERATE TO HEAVY RAIN AND POSSIBLY
FLASH FLOODING.

DISCUSSION...MESOSCALE ORGANIZATION HAD BEGUN TO REVEAL ITSELF
WITH A COLD POOL STRADDLING THE KS/NE BORDER AND ANOTHER IN SW/SC
KS. MODEL FORECASTS ARE MOVING THE COLD POOLS EAST MUCH FASTER
THAN WOULD BE EXPECTED AGAINST THE RESISTANCE OF THE FORECAST
40-55 KNOT LOW LEVEL JET. BUT THE COVERAGE AND INTENSITY OF
MODELED PRECIPITATION IN RECENT RUNS OF THE HRRR AND GFS...NOTING
CONVECTIVE FEEDBACK...SUPPORT THE NOTION OF A LONG DURATION
CONVECTIVE EVENT TONIGHT WHERE HEIGHT FALLS WILL OVERSPREAD THE
MODERATE TO STRONGLY UNSTABLE AIRMASS ALREADY IN PLACE. SREF MIXED
LAYER CAPE VALUES REMAIN AT OR ABOVE 2000 J/KG IN THE INFLOW
THROUGH 06Z.

FLASH FLOOD GUIDANCE...WHICH IS NOT PARTICULARLY LOW...AVERAGES 2
TO 3 INCHES PER 3-HOURS IN THIS REGION. STORM
MOTIONS...HOWEVER...ARE EXPECTED TO CONTRIBUTE TO A FLASH FLOOD
THREAT...WITH INDIVIDUAL CELLS TRAINING NORTHEASTWARD AND MCS
PROPAGATION TAKING THE LEADING EDGE SLOWLY EAST-SOUTHEASTWARD. A
RATHER BROAD LOW LEVEL JET WILL SUPPORT CONTINUED REDEVELOPMENT ON
THE WESTERN FLANK OF THE OUTFLOW AS WELL... ALLOWING FOR MULTIPLE
ROUNDS OF MDT/HVY RAIN AT SOME LOCATIONS...AND LOCAL TOTALS
POSSIBLY EXCEEDING 3-4 INCHES.

NOTE THAT THE GREATEST THREAT IS ANTICIPATED NEAR/NORTH OF WEAK
FRONTAL ZONE THAT WAS ANALYZED OVER SOUTHWEST KS/NORTHERN OK PER
21Z WPC MAP.

BURKE


ATTN...WFO...EAX...TSA...TOP...ICT...OUN...GID...DDC...

LAT...LON   39029529 39669557 39899627 39939753 39819820 38759865
            37629895 36899877 36589777 36389676 36259620 36499586
            36949564 37929530 38819521 39029529