Quantitative Precipitation Forecast
Issued by NWS

Current Version | Previous Version | Graphics & Text | 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 48 49 50
000
FOUS30 KWBC 220646
QPFERD

EXCESSIVE RAINFALL DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
245 AM EDT SUN MAR 22 2015

...VALID 06Z SUN MAR 22 2015 - 12Z MON MAR 23 2015...
...REFERENCE AWIPS GRAPHIC UNDER...DAY 1 EXCESSIVE RAINFALL...


SLIGHT RISK OF RAINFALL EXCEEDING FFG TO THE RIGHT OF A LINE FROM
30 WNW LFT 25 S ESF 10 NE HEZ 40 E JAN 30 SE NMM 50 NNW GZH
25 NE GZH 20 ESE GZH 25 SSW GZH 15 NNW MOB ASD 20 NNW PTN
30 WNW LFT.



..GULF COAST/SOUTHEAST...

THE LOW LEVEL INFLOW (20 TO 30 KNOTS BETWEEN 925 MB AND 850 MB)
CONTINUES
TO TRANSPORT HIGH MOISTURE AIR (WITH PRECIPITABLE WATER VALUES
NEAR 1.75
INCHES OVER SOUTHERN MS/SOUTHERN AL) UP AND OVER A SURFACE FRONT
EXTENDING
ACROSS SOUTHEAST LA/SOUTHERN AL/THE WESTERN PANHANDLE OF FL. THE
MOISTURE
AND LIFT AHEAD OF THE MID LEVEL SYSTEM OVER TX/OK BECOMES FOCUSED
ON AN
ELEVATED FRONT STRETCHING ACROSS MS/CENTRAL AL INTO CENTRAL GA.
THE BEST
INSTABILITY REMAINS OVER THE GULF OF MEXICO SOUTH OF THE SURFACE
FRONT...
BUT ELEVATED INSTABILITY IS TRANSPORTED NORTH TO THE ELEVATED
BOUNDARY.

THE DISCONNECT OF MID LEVEL LIFT AND SURFACE BASED INSTABILITY IS
KEEPING
RAINFALL RATES DOWN (THOUGH MESONET OBSERVATIONS HAVE SHOWN 0.50
TO 0.75
INCH PER HOUR RATES ACROSS SOUTHERN MS INTO THE PANHANDLE OF FL).
AS THE
SYNOPTIC SCALE LIFT INCREASES...A LARGE AREA OF 0.50 TO 0.75
INCHES OF QPF
IS EXPECTED ACROSS THE GULF COAST STATES PRIOR TO 22/12Z. LOCALLY
HIGHER
AMOUNTS ARE POSSIBLE...AS ELEVATED INSTABILITY IS TRANSPORTED
NORTHWARD.
ONE AND THREE HOUR FLASH FLOOD VALUES ARE GENERALLY ABOVE 2.50
INCHES
IN THESE AREAS...SO ORGANIZED FLASH FLOODING IS NOT EXPECTED.
HOWEVER...
DUE TO THE PRESENCE OF HIGH MOISTURE CONTENT AIR AND ELEVATED
INSTABILITY...
LOCAL FLOODING ISSUES ARE POSSIBLE. BECAUSE OF THIS...THE SLIGHT
RISK AREA
WAS DOWNGRADED TO A SEE TEXT...WHICH IS MAINLY FOR THE HEAVY RAIN
POTENTIAL
THROUGH 12Z.

AFTER 12Z...THE MID LEVEL SHORT WAVE CROSSES THE GULF COAST AND
SOUTHEAST STATES. THE BEST LIFT REMAINS NORTH OF THE SURFACE FRONT

AND BEST LOW LEVEL INSTABILITY. HOWEVER...HIGH MOISTURE CONTENT
AIR FOLLOWS THE BEST MID LEVEL LIFT ASSOCIATED WITH THE SHORT
WAVE. THE DISCONNECT BETWEEN THE BEST INSTABILITY AND BEST MID
LEVEL LIFT BECOMES MORE PRONOUNCED WITH TIME. AN AXIS OF 1.50 TO
2.00 INCHES OF QPF WAS EXTENDED ACROSS EAST CENTRAL AL/CENTRAL GA
INTO SOUTHERN SC...ALONG THE PATH OF BEST MID LEVEL LIFT.
HOWEVER...SINCE THE BEST INSTABILITY REMAINS REMOVED FROM THE BEST

LIFT...THE CHARACTER OF THE PRECIPITATION SHOULD BE MORE
STRATIFORM THAT CONVECTIVE. THE THREAT OF ORGANIZED FLASH FLOODING

DIMINISHES WITH TIME AFTER 12Z...SO THAT WHILE HEAVY RAIN IS
EXPECTED...FLASH FLOODING IS NOT. THIS BEING THE CASE...NO
EXCESSIVE AREA WAS ISSUED FOR THE SOUTHEAST STATES AFTER 22/12Z.

HAYES
$$





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