MESOSCALE PRECIPITATION DISCUSSION 0211
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
412 AM EDT SAT AUG 10 2013
 
AREAS AFFECTED...EASTERN OK...NORTHERN AR...SOUTHERN MO...WESTERN
TN...FAR SOUTHWEST KY 
 
CONCERNING...HEAVY RAINFALL...FLASH FLOODING LIKELY 
 
VALID 100803Z - 101403Z
 
SUMMARY...SEVERAL HOURS OF WEST TO EAST TRAINING CONVECTION IS
LIKELY TO PRODUCE FLASH FLOODING. HIGH RESOLUTION MODELS ARE
UNUSUALLY UNANIMOUS IN PRODUCING PARTICULARLY HIGH RAIN TOTALS
OVER NORTHERN ARKANSAS...WHERE THE MOST SIGNIFICANT FLOODING COULD
OCCUR.

DISCUSSION...EVENING SOUNDINGS SHOWED AN ATMOSPHERE SIMILARLY
MOIST AND UNSTABLE TO THE SETUP FROM RECENT NIGHTS OF HEAVY RAIN.
ORGANIZED MODEST FORCING HAD BEGUN TO ACT ON THIS
ENVIRONMENT...AND RADAR TRENDS SHOWED SUBSTANTIAL COVERAGE OF
INTENSIFYING CELLS WITH HEAVY RAIN AT 0745Z. EARLIER INITIATION OF
STORMS OVER SOUTHWEST MO APPEARED LINKED TO A 700-500 MB SHORTWAVE
TROUGH. THIS ACTIVITY WI WILL FIND BETTER INFLOW OVER SOUTHEAST MO
WHERE ADDITIONAL CELLS WERE INITIATING IN RESPONSE TO WARM
ADVECTION. STORM CLUSTERS SHOULD MOVE SLOWLY THROUGH SOUTHERN
MO...WITH MDT/HVY RAIN RATES. GIVEN THE COMPROMISED SOILS AND
EFFICIENT WARM RAIN PROCESS SEEN IN FORECAST SOUNDINGS SOME LOCAL
FLASH FLOODING IS LIKELY. EVENTUALLY...HOWEVER...INFLOW MAY BE
CUTOFF BY THE GROWING EVENT IN OK/AR.

PER RAP FORECASTS...A SLOW MOVING 700 MB TROUGH WILL COINCIDE WITH
CONVERGENCE AT THE NOSE OF THE 850 MB JET...ALSO COINCIDENT WITH
THE LEADING EDGE OF HIGHER MUCAPE VALUES. RADAR HAD BEGUN TO TELL
THE STORY OF CELLS INITIATING NEAR THE 700 MB TROUGH IN EASTERN OK
AND THEN BLOSSOMING AS THEY ENCOUNTER MORE FAVORABLE INFLOW/CAPE
COMBINATION OVER NORTHERN AR. A SIGNIFICANT AMOUNT OF TRAINING
SHOULD RESULT THROUGH 09-11Z...WITH PERHAPS MORE PROPAGATION TO
THE SOUTH AND EAST TOWARD INTERSTATE 40 LATER ON AS COLD POOLS
GROW. 

SIMILAR ENVIRONMENTS IN RECENT NIGHTS HAVE BEEN SUPPORTIVE OF AT
LEAST 1.5-2" PER HOUR RATES...WITH A QUICK 3-4" POSSIBLE WHEREVER
2 OR 3 ROUNDS TRAIN OVER A LOCATION. THE 00Z HIGH RESOLUTION MODEL
SUITE WAS UNUSUALLY UNANIMOUS IN PAINTING A BROAD SWATH OF
EXCESSIVE TOTALS HERE THROUGH MORNING...GENERALLY IN THE NORTHERN
3 ROWS OF COUNTIES IN AR. THIS CONSENSUS MAY SPEAK TO THE
DEFINITION OF THE FORCING MECHANISMS AND EFFICIENCY OF THE
ENVIRONMENT.

BURKE

ATTN...WFO...PAH...MEG...LSX...LZK...SGF...TSA...

ATTN...RFC...ABRFC...LMRFC...MBRFC...NCRFC...WGRFC...

LAT...LON   37309254 37709170 37709037 37278945 36408903 35378994
            34589367 34759572 35749519 36539338 37309254