MESOSCALE PRECIPITATION DISCUSSION 0338
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
826 PM EDT MON SEP 01 2014
 
AREAS AFFECTED...ERN KANSAS / NERN OKLAHOMA...ENEWD INTO W-CNTRL
INDIANA 
 
CONCERNING...HEAVY RAINFALL...FLASH FLOODING POSSIBLE 
 
VALID 020026Z - 020626Z
 
SUMMARY...EVENING TRENDS HAVE ALLOWED FOR GREATER CONFIDENCE IN A
FLASH FLOOD THREAT EXTENDING FROM WSW TO ENE ACROSS MISSOURI AND
ILLINOIS DEVELOPING THROUGH 06Z. TRAINING CONVECTION WITH 3-HRLY
RATES OF 3 TO 4 INCHES CAN BE EXPECTED.

DISCUSSION...ALTHOUGH SOME UNCERTAINTY EXISTED EARLIER THIS
EVENING WITH A REMNANT OUTFLOW BOUNDARY NOT HANDLED WELL BY 12Z
MODEL GUIDANCE...WITH CONVECTION NOW UNDERWAY BETWEEN THE OUTFLOW
BOUNDARY AND SYNOPTIC FRONT...ENOUGH CONFIDENCE IS IN PLACE TO
FOCUS ON AN EXTENDED REGION FOR AN ENHANCED FLASH FLOOD THREAT
OVERNIGHT. 00Z VAD WIND PLOTS SHOW SSWLY FLOW OF 2O TO 30 KTS FROM
TUL TO SGF WHICH IS FORECAST TO SLOWLY INCREASE AND VEER ACROSS
CNTRL/SRN MISSOURI WITH THE PASSAGE OF A SOMEWHAT BROAD UPPER
TROUGH SEEN ON WATER VAPOR IMAGERY. UPPER LEVEL JET ENHANCEMENT
TIED TO A WELL DEFINED SHORTWAVE CURRENTLY OVER THE CNTRL
NEBRASKA/KANSAS BORDER IS FORECAST TO OCCUR WITH THE
RIGHT-ENTRANCE REGION SETTING UP OVER THE THREAT AREA BETWEEN 03Z
AND 06Z. 

IN ADDITION TO LOW LEVEL CONVERGENT FLOW NEAR 850MB...SWLY LOW
LEVEL FLOW IS EXPECTED TO PARALLEL MEAN STORM MOTIONS TOWARD THE
ENE AT OR ABOUT 35 KTS CAUSING ONLY SLOW SYSTEM PROPAGATION TOWARD
THE SOUTHEAST OVER CNTRL MISSOURI INTO ILLINOIS.
MEANWHILE...CONVECTION FARTHER WEST ACROSS SERN KANSAS INTO
OKLAHOMA SHOULD FEATURE GREATER PROPAGATION TOWARD THE SOUTHEAST
ONCE A COLD POOL DEVELOPS GIVEN MORE OF A SRLY COMPONENT TO THE
LOW LEVEL FLOW. THE FLASH FLOOD THREAT ACROSS THE WRN PORTION OF
THE THREAT AREA SHOULD BE LIMITED. THE 12Z HI-RES ARW APPEARS TO
BE BEST HANDLING CURRENT RADAR TRENDS WHILE RUNS OF THE HRRR
BETWEEN 18Z AND 22Z MAY BE A BIT TOO FAR SOUTH. 

OTTO

ATTN...WFO...PAH...ILX...LSX...SGF...EAX...TSA...TOP...ICT...
OUN...

ATTN...RFC...ABRFC...LMRFC...MBRFC...NCRFC...OHRFC...

LAT...LON   38228929 37509205 36979449 36789629 36869693 36959723
            37539706 38469513 39159265 39589018 39798838 38868793
            38228929