MESOSCALE PRECIPITATION DISCUSSION 0653
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
347 PM EST TUE NOV 17 2015
 
AREAS AFFECTED...NERN LA TO THE MO BOOTHEEL...AND EWD TO THE MS
RIVER 
 
CONCERNING...HEAVY RAINFALL...FLASH FLOODING LIKELY 
 
VALID 172043Z - 180230Z
 
SUMMARY...FLASH FLOODING APPEARS LIKELY ACROSS NERN ARKANSAS INTO
SERN MISSOURI AS A LINE OF HEAVY RAIN APPROACHES AN AREA OF LOW
FLASH FLOOD GUIDANCE FROM THE WEST. BETTER ACCESS TO INSTABILITY
ACROSS NRN LOUISIANA COULD AlSO RESULT IN FLASH FLOODING WITH 6 HR
RAINFALL TOTALS OF 3-6 INCHES EXPECTED.

DISCUSSION...A NEARLY CONTINUOUS LINE OF HEAVY RAIN...CONTAINING
AVERAGE RAINFALL RATES OF 0.5 TO 1.0 IN/HR WITH LOCALIZED RATES UP
TO 2+ IN/HR...ARE OCCURRING WITH A COLD FRONT MOVING EAST AT 20-25
MPH. THE LOCALLY HIGHER RATES ARE OCCURRING WITH AREAS OF TRAINING
WITHIN THE LINE AND FROM PRE-FRONTAL SHOWERS WITHIN AN AXIS OF
INSTABILITY ACROSS LOUISIANA. MOISTURE REMAINS HIGHLY ANOMALOUS
FOR MID-NOVEMBER AS SEEN BY 2 INCH PWATS IN SPECIAL 18Z LCH AND
LZK SOUNDINGS. IN ADDITION...JUST PRECEDING THE COLD
FRONT...850-700 MB FLOW INCREASED TO A REMARKABLE 75 KTS VIA THE
KLZK VAD WIND PROFILE. 

GIVEN UPPER DIFLUENCE ACROSS THE THREAT AREA REMAINS ROBUST WITH
AN APPROACHING 110-130 KT UPPER JET...AND LITTLE CHANGE IS
ANTICIPATED IN THE COLD FRONTAL SPEED THROUGH 03Z...THE ENTIRE
LINE OF HEAVY RAIN IS EXPECTED TO TRANSLATE EAST OVER THE NEXT 6
HOURS. LOW LEVEL FLOW OF 70+ KTS SHOULD CONTINUE JUST AHEAD OF THE
COLD FRONT PAST 00Z. THIS IS ESPECIALLY CONCERNING ACROSS NERN
ARKANSAS INTO SERN MISSOURI WHERE ANTECEDENT RAINFALL HAS LOWERED
FFG TO 1-2 INCHES IN 1 HOUR AND 3 HOURS. FARTHER SOUTH...ALTHOUGH
FFG IS HIGHER...BETTER ACCESS TO INSTABILITY AND ELEMENTS OF
TRAINING WILL CONTINUE TO CAUSE SPOTTY LOCATIONS TO RECEIVE HOURLY
RAINFALL RATES OF 2-3 IN/HR. FLASH FLOODING IS LIKELY ACROSS THE
ENTIRE MPD THREAT AREA.
  
OTTO

ATTN...WFO...JAN...LZK...MEG...PAH...SGF...SHV...

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

LAT...LON   37119047 36828991 35648990 34349014 32899058 
            31879158 31999235 33469219 35239188 36369126 
            36909090