MESOSCALE PRECIPITATION DISCUSSION 0616
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
940 PM EDT SUN OCT 25 2015
 
AREAS AFFECTED...FAR EAST TX...MUCH OF LA...SOUTHERN
AR...SOUTHWEST MS 
 
CONCERNING...HEAVY RAINFALL...FLASH FLOODING POSSIBLE 
 
VALID 260140Z - 260600Z
 
SUMMARY...EFFICIENT WARM RAIN PROCESSES WILL CONTINUE TO PRODUCE A
HEAVY RAIN THREAT OVER PORTIONS OF THE WESTERN AND CENTRAL GULF
STATES THROUGH THE EARLY MORNING HOURS. FLASH FLOODING IS POSSIBLE
IN LOCATIONS WHERE SOILS ARE SATURATED. 
 
DISCUSSION...THE LARGE AREA OF MODERATE TO HEAVY RAIN CONTINUES
ACROSS FAR EAST TX... MUCH OF LA INTO SOUTHERN AR AND AND MUCH OF
MS. THE RAINFALL IS BEING DRIVEN BY LIFT IN THE COMMA HEAD ACROSS
NORTHERN LA AND SOUTHERN AR...AHEAD OF A SHORT WAVE TRACKING
ACROSS SOUTHWEST LA. BANDED RAINFALL IS OCCURRING ACROSS EASTERN
TX AND NORTHERN AND CENTRAL LA...AND THE BANDED RAINFALL IS
AUGMENTED BY LIFT IN THE PERSISTENT MID/UPPER LEVEL DIFFLUENCE
ACROSS THE GULF STATES. INSTABILITY APPEARS TO BE SLANTWISE...AS
LIGHTNING STRIKES ARE OCCURRING OVER WEST CENTRAL LA. 

AS THE SHORT WAVE TRACKS SLOWLY NORTHEAST... THE BANDED RAINFALL
SHOULD CONTINUE TO ROTATE SLOWLY WEST NORTHWEST ACROSS PORTIONS OF
FAR EAST TX...AS WELL AS NORTHERN AND PORTIONS OF CENTRAL LA.
RAINFALL RATES BETWEEN ONE-HALF TO ONE INCH AN HOUR COULD RESULT
IN RAINFALL TOTALS OVER 2.00 INCHES IN THESE AREAS. FLASH FLOODING
IS POSSIBLE ACROSS AREAS OF FAR EAST TX/WEST CENTRAL LA WHERE
SOILS HAVE BECOME SATURATED DUE TO EARLIER HEAVY RAINFALL.

FURTHER EAST...A 40 TO 50 KNOT LOW LEVEL SOUTHEAST FLOW CONTINUES
TO TRANSPORT 2.25 TO 2.50 INCH PRECIPITABLE WATER AIR UP AND OVER
A FRONTAL BOUNDARY ACROSS SOUTHERN LA. INSTABILITY IN THE LOW
LEVEL INFLOW IS MARGINAL...AS THE 00Z KLIX SOUNDING SHOWED AN
SBCAPE VALUE OF 330 J/KG. THE DEEP MOISTURE AND MARGINAL
INSTABILITY HAS RESULTED IN HOURLY RAINFALL RATES BETWEEN 2.00 AND
3.00 INCHES (BASED ON THE MRMS RAINFALL RATE PRODUCT AND THE KLIX
RADAR). 

THERE IS A STRONG MODEL SIGNAL FOR 2-4 INCHES OF RAINFALL ACROSS
PORTIONS OF SOUTHEAST LA AND SOUTHWEST MS THROUGH 26/06Z. THE 23Z
HRRR/12Z WRF-ARW/18Z NAM CONEST SHOWED LOCAL RAINFALL AMOUNTS OF
6+ INCHES. INSTABILITY COULD END UP BEING THE LIMITING FACTOR FOR
RAINFALL AMOUNTS THIS HIGH...BUT GIVEN THE DEEP MOISTURE IS
PLACE...FLASH FLOODING IS POSSIBLE.

HAYES

ATTN...WFO...JAN...LCH...LIX...LZK...MOB...SHV...

ATTN...RFC...LMRFC...WGRFC...

LAT...LON   33689229 33479154 33219121 33039093 32469048 
            32128993 31918966 31888965 30848924 30128909 
            29768923 29168991 28989059 29389089 30009135 
            30839235 30849238 30839278 30609311 30329337 
            30289348 30159352 30079383 30139407 30379428 
            31009439 31779441 32609437 33109395 33379366 
            33629306