Quantitative Precipitation Forecast
Issued by NWS

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FOUS30 KWBC 220701
QPFERD

EXCESSIVE RAINFALL DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
300 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 CONTENT 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/WESTERN PANHANDLE OF FL. THE MOISTURE
BECOMES FOCUSED ON AN ELEVATED FRONT STRETCHING FROM 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 SUPPRESSED (THOUGH MESONET OBSERVATIONS
HAVE SHOWN 0.50 TO 0.75 INCHES 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 GUIDANCE 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 PRIOR TO 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 THAN CONVECTIVE. THE THREAT FOR ORGANIZED FLASH
FLOODING DIMINISHES AFTER 12Z...SO WHILE HEAVY RAIN IS EXPECTED.
FLASH FLOODING IS NOT EXPECTED. THIS BEING THE CASE...NO EXCESSIVE
AREA WAS ISSUED FOR THE SOUTHEAST AFTER 22/12Z.

HAYES
$$




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