Quantitative Precipitation Forecast
Issued by NWS

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FOUS30 KWBC 161328
QPFERD

EXCESSIVE RAINFALL DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
928 AM EDT SAT AUG 16 2014

...VALID 15Z SAT AUG 16 2014 - 12Z SUN AUG 17 2014...
...REFERENCE AWIPS GRAPHIC UNDER...DAY 1 EXCESSIVE RAINFALL...


SLIGHT RISK OF RAINFALL EXCEEDING FFG TO THE RIGHT OF A LINE FROM
40 E CYEN 15 SSE K5H4 10 NNE K2D5 10 SSW 8D3 10 NE ATY
30 NE HON 35 NNW HON 50 WSW ABR 15 SW KY19 30 WSW KHZE
15 SSE KS25 15 NE SDY 35 NNW SDY 25 SSE CWAQ 30 NE CWAQ
25 WSW CWWF 25 E CWWF 40 E CYEN.

THERE IS STILL A THREAT FOR SOME LOCALLY HEAVY AND EVEN ISOLATED
EXCESSIVE RAINS FOR PARTS OF ND AND SD INTO THE LATER SATURDAY
AFTERNOON HOURS.  THE 12Z RAOBS SHOWED A RATHER NARROW AXIS OF
VERY HIGH MOISTURE/PWS RUNNING NORTHWEST TO SOUTHEAST FROM
NORTHWESTERN ND INTO NORTHEASTERN SD..WITH OBSERVED PWS AS HIGH AS
1.86 AT BIS.  THE 40 K INDEX AT BIS ALSO SHOWS JUST HOW MOIST AND
UNSTABLE THE AIRMASS IS AT THIS TIME.  THIS MOIST AND UNSTABLE
AIRMASS ALONG WITH THE SMALL CIRCULATION VICINITY OF CENTRAL ND
WILL SUPPORT THE POTENTIAL FOR ADDITIONAL ISOLATED HEAVY
CONVECTION WITHIN THE THREAT AREA..AT LEAST INTO THE LATER
SATURDAY AFTERNOON HOURS.  BY LATER SATURDAY AFTERNOON AND
EVENING..THE CIRCULATION IS FORECAST TO MOVE INTO A LESS MOIST AND
UNSTABLE AIRMASS..LESSENING THE THREAT FOR HEAVY RAINS.  SOME
ISOLATED 1+ INCH RAINS IN AN HOUR OR SO AND 1-2 INCH RAINFALL
AMOUNTS INTO THE SATURDAY AFTERNOON HOURS COULD CAUSE SOME
ISOLATED FLOODING PROBLEMS.


SLIGHT RISK OF RAINFALL EXCEEDING FFG TO THE RIGHT OF A LINE FROM
15 SSW 1H2 20 ENE SAR 15 E FAM 40 W FAM 20 E TBN TBN 15 WNW TBN
10 S AIZ AIZ 25 WSW JEF COU 30 N COU 40 SE IRK 30 SE IRK
20 ENE IRK 25 SSW FFL FFL AWG 20 SE MUT 20 SE GBG 15 ENE AAA
15 WSW CMI MTO 15 SSW 1H2.

CONVECTION CONTINUES EARLY THIS MORNING AHEAD OF AN MCV VICINITY
OF THE MO/IA BORDER.  THE LOW LEVEL INFLOW INTO THIS SYSTEM HAS
WEAKENED PAST FEW HOURS AND THIS GENERAL WEAKENING TREND IN THE
LOW LEVEL INFLOW SHOULD CONTINUE THROUGH 16/15Z...AND WITH IT THE
HEAVIEST RAIN POTENTIAL. BOTH THE LATEST HRRR AND RAP SHOW SOME
ACTIVITY WITH THE MCV THROUGH 16/15Z...SO A SLIGHT RISK WILL STILL
BE MAINTAINED THROUGH THE WEAKENING PHASE OF THE CONVECTION THIS
MORNING.

THE MCV WILL CONTINUE TO FOCUS INSTABILITY AND MOISTURE INTO THE
EVENING HOURS. THE LOW LEVEL INFLOW INCREASES AGAIN AFTER 17/00Z
ACROSS EASTERN MO AND WEST CENTRAL IL. PRECIPITABLE WATER VALUES
REMAIN IN THE TWO STANDARD DEVIATION ABOVE NORMAL RANGE (BETWEEN
1.75 AND 2.00 INCHES) ALONG AND NORTH OF THE FRONTAL BOUNDARY AS
THE LOW LEVEL INFLOW INCREASES...AND THERE IS A MULTI MODEL SIGNAL
THAT AN MCS COULD FORM OVER EASTERN MO AFTER 17/03Z... AND TRACK
ACROSS WEST CENTRAL IL THROUGH THE END OF THE PERIOD. A SWATH OF
1.00 TO 1.50 INCHES OF QPF WAS PLACED ALONG THE TRACK OF THE
POSSIBLE MCS. WHILE THE BASIN AVERAGED QPF IS NOT ABOVE THE THREE
HOUR FLASH FLOOD GUIDANCE VALUES...THE HIGH RAINFALL RATES COULD
LEAD TO FLASH FLOODING...AND THIS AREA WAS MAINTAINED IN THE
SLIGHT RISK FOR AFTER 17/00Z.

TERRY
$$





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