MESOSCALE PRECIPITATION DISCUSSION 0362
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
1238 AM EDT WED SEP 10 2014
 
AREAS AFFECTED...NRN MISSOURI / SRN IOWA INTO CNTRL/NRN ILLINOIS 
 
CONCERNING...HEAVY RAINFALL...FLASH FLOODING LIKELY 
 
VALID 100436Z - 101030Z
 
SUMMARY...REPEATING CELL TRACKS ARE EXPECTED TO CONTINUE THE FLASH
FLOOD THREAT OVER NRN MISSOURI / SRN IOWA IN THE SHORT
TERM...WHILE SHIFTING DOWNSTREAM INTO ILLINOIS AFTER 06/07Z.
ADDITIONAL RAINFALL AMOUNTS OF 3-6 INCHES ARE EXPECTED FROM NERN
MISSOURI INTO W-CNTRL ILLINOIS BY 10Z.

DISCUSSION...A LARGE MCC CURRENTLY DEVELOPING OVER IOWA AND
MISSOURI HAS ALREADY PRODUCED NUMEROUS REPORTS OF FLASH FLOODING
WITHIN 50 MILES OF EITHER SIDE OF THE MISSOURI/IOWA BORDER WITH
LOCALIZED RAINFALL RATES OF 3+ IN/HR AS EVIDENCED IN SRN NODAWAY
AND SRN SULLIVAN COUNTIES IN NWRN AND N-CNTRL MISSOURI EARLIER
TONIGHT. A STRONG LLJ OF 50-60 KTS FROM THE SSW AS SEEN ON VAD
WIND PLOTS FROM KTWX AND KEAX...IS ADVECTING WARM/MOIST AIR ATOP A
SHARPLY DEFINED STATIONARY FRONT STRETCHING SEWD FROM A LOW IN
SERN NEBRASKA.

AS A 700 MB LOW / SHORTWAVE CONTINUES TO STRENGTHEN AND ADVANCE
FROM SERN SOUTH DAKOTA TOWARD WRN WISCONSIN...A SURFACE LOW IN
SERN NEBRASKA WILL TRANSLATE NEWD OVER THE NEXT 3-6
HOURS...CAUSING LOW LEVEL FLOW TO VEER. THE VEERING FLOW IS
EXPECTED TO PARALLEL AND EXCEED MEAN NELY STORM MOTIONS OF 30-35
KTS...SETTING UP A STRONG SIGNAL FOR TRAINING CONVECTION FROM NERN
MISSOURI INTO CNTRL/NRN ILLINOIS. 

THE 12Z HRW ARW HAS BEEN HANDLING THIS SITUATION THE BEST SO
FAR...AND WITH ADJUSTMENTS MADE FOR CURRENT RADAR TRENDS...FLASH
FLOODING APPEARS LIKELY AS 2+ INCH PWAT AIRMASS FILTERS INTO
ILLINOIS LATER THIS MORNING.

OTTO

ATTN...WFO...DMX...DVN...EAX...ILX...LOT...LSX...OAX...TOP...

ATTN...RFC...MBRFC...NCRFC...OHRFC...

LAT...LON   42338945 42118767 41328725 40348812 39449024 
            39139325 39479465 39949555 40269584 40729589 
            41199479 41479343 41749164