Quantitative Precipitation Forecast
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FOUS30 KWBC 151857
QPFERD

EXCESSIVE RAINFALL DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
256 PM EDT FRI AUG 15 2014

...VALID 18Z FRI AUG 15 2014 - 00Z 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
30 ENE BIS 20 SSW ABR 45 WNW HON 40 SSW MBG 35 SE HEI 10 SW GDV
25 NNE OLF 20 NNW ISN 30 ENE BIS.

SLIGHT RISK OF RAINFALL EXCEEDING FFG TO THE RIGHT OF A LINE FROM
15 NE IKV 20 NE GBG 15 WNW IJX 15 NNW COU 10 WNW IXD 25 SSE BIE
15 E OLU 15 E YKN 25 WNW SLB 15 NE IKV.

SLIGHT RISK OF RAINFALL EXCEEDING FFG TO THE RIGHT OF A LINE FROM
25 NNE HOB 10 NW MRF 80 S MMCS 110 SE DUG 55 SSW DUG 20 E OLS
35 SSW SAD 30 NE SAD 30 NE TCS 55 W CVS 25 NNE HOB.


...NRN/CNTL PLAINS/MID MS VALLEY...

WAS ABLE TO TIGHTEN UP THE SLIGHT RISK AREA FROM PARTS OF MT INTO
ND WHERE PRECIPITABLE WATER VALUES OF 170 TO 210 PCT ARE IN PLACE
IN A NORTHWEST TO SOUTHEAST ORIENTED RIBBON.  THE FLOW ALOFT
SHOULD CONTINUE TO BE HIGHLY DIFLUENT WITH A CLOSED LOW OVER WA/OR
AND THE RIDGE AXIS OFF TO THE EAST.  ALL THAT COMBINED WITH
SEVERAL MID LEVEL SHORTWAVES WILL RESULT CONVECTION THAT WILL BE
CAPABLE OF PRODUCING SOME LOCALLY HEAVY RAINFALL.

A SECOND AREA OF SLIGHT RISK WAS INDICATED OVER PARTS OF THE
CENTRAL MS VALLEY INTO PARTS OF THE WESTERN OH/TN VALLEY.  A
SHORTWAVE TROF MOVING EASTWARD ACROSS KS/NE WILL HELP TRIGGER AND
FOCUS CONVECTION LATER TONIGHT WHICH MAKES ITS WAY EASTWARD
OVERNIGHT.  AREAL AVERAGE AMOUNTS OF 2 TO 2.5 INCHES WAS DEPICTED
ALONG FAR SOUTHERN IA AND NORTHERN MO...WITH THE POTENTIAL FOR
ISOLATED HIGHER RAINFALL AMOUNTS WITHIN THIS AREA.  OUR SLIGHT
RISK ENCOMPASSES THE POSSIBILITY THAT THE MODEL SOLNS FAVORING A
MORE NORTHERLY TRACK VERIFY AS WELL AS OUR FAVORED TRACK TO THE
SOUTH.  STORMS HERE SHOULD BE ABLE TO INTERCEPT HIGHER
MOISTURE-CONTENT AIR STREAMING INTO THE REGION WITH PRECIPITABLE
WATER VALUES IN THE 1.75-2" RANGE.  WHILE FFG VALUES INITIALLY
WERE HIGH ACROSS WESTERN IOWA...RAINFALL THIS MORNING HAS LEFT
BEHIND ISOLATED AMOUNTS ON THE ORDER OF 2 INCHES.  WHILE THIS MAY
RESULT IN LOWER FFG VALUES...DID NOT FEEL IT WAS ENOUGH TO WARRANT
UPGRADING THE SLIGHT RISK.

...SOUTHERN NM TO FAR WEST TX...

12Z SOUNDINGS SHOWED AN AIRMASS WITH PW VALUES RUNNING FROM 130 TO
180 PCT OF NORMAL STILL IN PLACE ACROSS THE SOUTHWESTERN UNITED
STATES.  THE EPZ SOUNDING SHOWED A TALL...SKINNY CAPE PROFILE WITH
LIGHT WINDS FROM THE SURFACE UP TO AT LEAST 300 MB SUGGESTING THAT
ANY STORMS WHICH FORM WILL BE SLOW MOVERS.  IN ADDITION...WATER
VAPOR SATELLITE IMAGERY SHOWED A MID LEVEL SHORTWAVE APPROACHING
FROM AZ WHICH MAY HELP INITIATE/FOCUS CONVECTION THROUGHOUT THE
EVENING AND PERHAPS AGAIN ON SATURDAY AFTERNOON.

...NORTHERN WA/ID PANHANDLE...FAR WESTERN MT...

ISOLATED PROBLEMS DUE TO RUN OFF...ESPECIALLY IN BURN SCARRED
AREAS AND IN NORMALLY DRY WASHES...MAY DEVELOP FROM NORTHERN WA
INTO FAR WESTERN MT ONCE SHOWERS AND THUNDERSTORMS BECOME MORE
NUMEROUS THIS AFTERNOON.  THE 12Z SOUNDING FROM GEG HAD A PW WHICH
WAS AT THE 99TH PERCENTILE FOR THE DATE AND 172 PERCENT OF NORMAL
DESPITE HAVING A CLOSED COLD CORE LOW IN THE VICINITY.  GIVEN THE
SOUTHERLY FLOW OF 20 KTS OR SO AT BOTH GEG AND AT TFX...THINK THAT
INDIVIDUAL CELLS WILL MOVE ALONG STEADILY TO PRECLUDE MORE THAN
ISOLATED PROBLEMS.

BANN
$$




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