MESOSCALE PRECIPITATION DISCUSSION 0204
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
217 AM EDT THU AUG 08 2013
 
AREAS AFFECTED...NORTHERN OK...SOUTHERN KS...SOUTHWEST
MO...NORTHERN AR 
 
CONCERNING...HEAVY RAINFALL...FLASH FLOODING LIKELY 
 
VALID 080616Z - 081116Z
 
SUMMARY...COVERAGE OF HEAVY RAIN WILL INCREASE WITHIN WARM
ADVECTION REGIME. MOIST ENVIRONMENT AND LOCAL TRAINING IS LIKELY
TO YIELD FLASH FLOODING.

DISCUSSION...LARGE SCALE IS SETUP VERY FAVORABLE FOR CLUSTERS OF
THUNDERSTORMS WITH HEAVY RAIN TO EXPAND IN COVERAGE NORTH OF A
SURFACE FRONT ANALYZED THROUGH OK/AR. MODELS DEPICT CELL MOTIONS
10 KT TO THE NE WHILE CORFIDI VECTORS BRING CLUSTERS OF
CELLS/LOCAL MCS E OR ENE AT 10 KT. WINDS SURFACE TO 850 MB HAD
SIGNIFICANT EASTERLY COMPONENT TO YIELD BOTH WARM ADVECTION
INITIATING WIDESPREAD CELLS OVER CENTRAL/NORTHERN OK...AND STRONG
CONVERGENCE AT LEADING EDGE OF MCS ENTERING NORTHWEST OK. GREATER
CAPE AND CONVERGENCE SHOULD FAVOR NW/NC OK...BUT CELLS IN CENTRAL
OK COULD YIELD FLASH FLOODING AS THEY PREFERENTIALLY REDEVELOP AND
TRAIN RATHER THAN PROPAGATING INTO THE DRIER AIR SOUTH OF THE
FRONT. MEANWHILE...CLUSTERS OF DEEP CONVECTIVE CELLS WERE
BLOSSOMING FROM NE OK ACROSS FAR SW MO INTO NORTHERN AR AT
06Z...FORCED BY ADVECTION JUST SLIGHTLY MORE ELEVATED...WITH WINDS
MORE SOUTHWESTERLY AT 800-700 MB. 

THE SREF FORECASTS MIXED LAYER CAPES TO REMAIN NEAR OR ABOVE 1000
J/KG OVER MOST OF THE REGION THROUGH 12Z...AND WITH WARM ADVECTION
SUSTAINED THROUGH THAT TIME AND BEYOND...WOULD EXPECT EXTENSIVE
COVERAGE OF CONVECTION. WE NOTE VERY GOOD AGREEMENT TO THE
EVOLUTION OF THIS EVENT BETWEEN THE HRRR AND EXPERIMENTAL NAM
CONEST AVAILABLE AT WPC. MUCH OF THE OTHER GUIDANCE APPEARED TOO
FAR NORTH...AND THE GFS DISPLAYED SOME FEEDBACK PROBLEMS AFFECTING
ITS LOW LEVEL WIND FIELDS.

EARLIER BEAVER OK MESONET SITE IN THE PANHANDLE OBSERVED 2.04
INCHES IN 30 MINUTES...EQUATING TO A 4 INCH PER HOUR RAIN RATE.
ENVIRONMENT CHANGES LITTLE TO THE EAST...AND THUS...FLASH FLOODING
IS A SIGNIFICANT CONCERN. THE MAIN SWATH OF ACTIVITY SHOULD REMAIN
AT THE SOUTHERN EDGE OF THE LOWEST FLASH FLOOD GUIDANCE OVER PARTS
OF SE KS/SW MO...BUT LESS INTENSE STORMS WITH STILL EFFICIENT
RAINFALL COULD BUILD NORTHWARD INTO THOSE AREAS TOWARD 10-12Z.

BURKE

ATTN...WFO...MEG...LZK...SGF...TSA...ICT...OUN...DDC...AMA...

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

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