Flash Flood Guidance
Issued by NWS

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47
000
AWUS01 KWNH 031649
FFGMPD
TNZ000-ALZ000-MSZ000-LAZ000-ARZ000-TXZ000-OKZ000-032230-

MESOSCALE PRECIPITATION DISCUSSION 0296
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
1249 PM EDT FRI JUL 03 2015

AREAS AFFECTED...ARKLATEX...ACROSS LOWER MS VALLEY...INTO SRN
TN/NWRN AL

CONCERNING...HEAVY RAINFALL...FLASH FLOODING LIKELY

VALID 031644Z - 032230Z

SUMMARY...A BROAD THREAT FOR FLASH FLOODING WILL CONTINUE THROUGH
THE AFTERNOON FOR LOCATIONS FROM THE ARKLATEX INTO PORTIONS OF THE
DEEP SOUTH. THE THREAT IS EXPECTED TO SHIFT SWD DURING THE
AFTERNOON INTO NERN TEXAS AND SRN ARKANSAS WHERE GREATER
INSTABILITY SHOULD BE PRESENT.

DISCUSSION...AT 1630Z...A LARGE AREA OF CONVECTION EXTENDED FROM
THE RED RIVER...ENEWD ACROSS THE LOWER MISSISSIPPI VALLEY INTO NRN
MISSISSIPPI AND ALABAMA. RELATED OUTFLOW BOUNDARIES HAVE SET UP A
10-15 F TEMPERATURE GRADIENT ACROSS THE DEEP SOUTH WITH RELATIVELY
CLEAR SKIES SOUTH OF THE ONGOING CONVECTION/OUTFLOW ALLOWING FOR
GROWING SURFACE BASED INSTABILITY.

IR SATELLITE AND CIMSS OVERSHOOTING TOP ALGORITHM SHOWED THE
STRONGEST UPDRAFTS DEVELOPING EWD IN AND AROUND THE MISSISSIPPI
RIVER VALLEY WHICH IS THE GREATEST SHORT TERM THREAT FOR FLASH
FLOODING AS UNIDIRECTIONAL FLOW CONTINUES TO ALLOW PERIODS OF
TRAINING WITH RAINFALL RATES MAXING OUT NEAR 2 IN/HR ON TOP OF
SATURATED SOILS.

ADDITIONAL CONVECTION IS EXPECTED TO DEVELOP NEAR AND SOUTH OF THE
PRESENT OUTFLOW LOCATION ACROSS THE ARKLATEX INTO SRN ARKANSAS AS
A 700 MB SHORTWAVE EXTENDING ACROSS THE OKLAHOMA/ARKANSAS BORDER
PROGRESSES SLOWLY SEWD THIS AFTERNOON. WHILE FFG IS HIGHER TO THE
SOUTH...THERE IS EXPECTED TO BE BROAD 850 MB CONFLUENCE ACROSS THE
ENTIRE REGION ALONG WITH DIFFLUENT UPPER LEVEL FLOW WHICH SHOULD
HELP TO ENHANCE UPWARD MOTION. WITH AREA PWATS NEAR 2
INCHES...MOISTURE REMAINS MORE THAN CAPABLE OF RAINFALL RATES NEAR
2 IN/HR AND UNIDIRECTIONAL FLOW SHOULD CAUSE SOME LOCATIONS TO
TRAIN. THIS IDEA IS SUPPORTED BY NEWLY ARRIVING 12Z HI-RES MODEL
GUIDANCE WITH 3-5 INCHES POSSIBLE.

OTTO

...PLEASE SEE WWW.WPC.NCEP.NOAA.GOV FOR GRAPHIC PRODUCT...

ATTN...WFO...BMX...HUN...JAN...LZK...MEG...OHX...SHV...

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

LAT...LON   35618923 35508762 35338724 34808722 34288750
            33978817 33398939 33069130 32999335 33149487
            33749516 34219410 34459337 35199225 35519128
            35468991


USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.