Quantitative Precipitation Forecast
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FOUS30 KWBC 140715
QPFERD

EXCESSIVE RAINFALL DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
314 AM EDT MON JUL 14 2014

...VALID 06Z MON JUL 14 2014 - 12Z TUE JUL 15 2014...
...REFERENCE AWIPS GRAPHIC UNDER...DAY 1 EXCESSIVE RAINFALL...


SLIGHT RISK OF RAINFALL EXCEEDING FFG TO THE RIGHT OF A LINE FROM
15 SE AJG 25 ESE ILN 15 ESE UNV 10 NW PSF AUG 40 SSE RKD
25 NNE PVC 20 SSE JFK 10 N NHK 10 SE LKU 25 N CHO 25 NE HSP GEV
10 SSW 1A5 20 W GAD 30 ESE TUP 30 SW GWO 15 SSE ELD 25 SSE MWT
25 E RUE 40 SSW CIR 25 SW FAM 15 SE AJG.


...PORTIONS OF THE LOWER MISSISSIPPI VALLEY INTO THE TENNESSEE
VALLEY...LOWER OHIO VALLEY...MID ATLANTIC...AND NORTHEAST...

ADJUSTED THE PREVIOUS SLIGHT RISK AREA FARTHER DOWNSTREAM THIS
PERIOD...NOW CLIPPING NORTHERN PORTIONS OF THE LOWER MS VLY...THE
TN VALLEY... LOWER OH VALLEY...WHILE CONTINUING ACROSS THE
MID-ATLANTIC AND NORTHEAST. THE ACTIVE PATTERN WILL CONTINUE THIS
PERIOD AS THE ANOMALOUS DEEP UPPER TROUGH DROPS INTO THE UPPER AND
EVENTUALLY MID MS VLY...BECOMING MORE AMPLIFIED AS IT DOES SO AS
STRONG SHORTWAVE ENERGY ROTATES ON THE BACK SIDE. UPPER LEVEL
HEIGHT FALLS WILL BE MOST PRONOUNCED ACROSS EASTERN PORTIONS OF
THE CENTRAL/NORTHERN PLAINS AS WELL AS THE MID/UPR MS
VALLEYS...HOWEVER AT THE SAME TIME THE AMPLIFYING UPPER TROUGH
WILL BECOME MORE PARALLEL TO THE SURFACE FRONT EAST OF THE TROUGH
AXIS. THIS WILL LEAD TO MULTIPLE ROUNDS OF CONVECTION...THE FIRST
ASSOCIATED WITH AND INITIAL SPIKE OF RIGHT-ENTRANCE REGION UPPER
FORCING (DIVERGENCE ALOFT...LOW-MID FGEN) ALONG THE INITIAL
PRE-FRONTAL TROUGH...WITH THE NEXT ROUND OF MORE ORGANIZED
ACTIVITY EXPECTED LATER IN THE PERIOD (TONIGHT INTO EARLY TUE)
ASSOCIATED ALONG A BETTER-DEFINED AXIS OF RIGHT ENTRANCE REGION
UPPER FORCING...CLOSER TO THE MAIN COLD FRONT GRADUALLY
APPROACHING FROM THE EAST. PW VALUES AHEAD OF THE MAIN COLD FRONT
WILL REMAIN BETWEEN 1.75 AND 2.00+ INCHES...THOUGH STRONG
DEEP-LAYER INSTABILITY WILL BE LACKING AS MUCAPES GENERALLY RANGE
BTWN 1000-2000 J/KG OVER THE SOUTHERN PORTION OF THE OUTLOOK AREA
AND 500-1000 J/KG OVER THE NORTH.  STILL...THE POTENTIAL FOR HEAVY
TO LOCALLY EXCESSIVE RAINFALL WILL BE EXACERBATED BY THE INCREASED
LIKELIHOOD OF TRAINING CONVECTION AS THE STRENGTHENING
SOUTHWESTERLY LOW-LEVEL INFLOW BECOMES MORE PARALLEL TO THE MEAN
850-300 MB FLOW WITH TIME AS THE TROUGH AMPLIFIES...WHILE EQUALING
(OR IN SOME AREAS EXCEEDING) THE MAGNITUDE OF THE MEAN FLOW. WPC
LEANED A LITTLE MORE HEAVILY ON THE HIGHER-RESOLUTION GUIDANCE
(ESPECIALLY THE WRF-ARW...4KM NAM CONEST...RGEM) IN THE NEAR TERM
WITH RESPECT TO THE TIMING...AS THE GLOBAL ENSEMBLE MEANS ARE A
TAD TOO SLOW WITH THE SOUTHWARD PROPAGATION THROUGH THE LOWER OH
VALLEY AND INTO THE TN VALLEY. QPF WITHIN THE OUTLOOK AREA AVERAGE
BETWEEN 1 AND 2.5 INCHES...HOWEVER AS PER THE HIGHER RESOLUTION
GUIDANCE LOCALIZED AMOUNTS OVER 4 INCHES ARE EXPECTED.
FURTHERMORE...EXPECT THE FFG TO CONTINUE TO LOWER WITH TIME GIVEN
THE MULTIPLE ROUNDS OF CONVECTION...THEREBY MAKING RUNOFF ISSUES
MORE LIKELY AS WE GET INTO LATER THIS AFTN AND OVERNIGHT.


...CENTRAL/SOUTHERN ROCKIES INTO PORTIONS OF THE CENTRAL/SOUTHERN
HIGH PLAINS...

THE SLIGHT RISK AREA WAS MAINTAINED IN THE LEE OF THE CENTRAL TO
SOUTHERN ROCKIES WHERE PW VALUES ARE EXPECTED TO REMAIN ABOVE
AVERAGE IN THE VICINITY OF THE WEAKENING FRONT OVER THE SOUTHERN
PLAINS.  WHILE THIS INITIAL FRONT IS EXPECTED TO CONTINUE TO
WEAKEN AND SUBSEQUENTLY LEAD TO WEAKENING UPSLOPE FLOW FROM NORTH
TO SOUTH...THERE SHOULD BE RE-STRENGTHENING OF THE UPSLOPE POST
FRONTAL FLOW DURING THE DAY ON MONDAY IN THE WAKE OF THE SECOND
SURGE OF COLD AIR SINKING SOUTHWARD ACROSS THE MID SECTION OF THE
NATION.  ADDITIONAL WIDESPREAD SCATTERED CONVECTION
POSSIBLE---WITH ISOLATED RUNOFF ISSUES POSSIBLE ESPECIALLY WHERE
FFG VALUES HAVE LOWERED FROM YESTERDAY`S CONVECTION.


...SOUTHWEST...

LATEST GUIDANCE CONTINUES TO SHOW A NORTHWESTWARD PUSH OF PW
VALUES BETWEEN 1.5-2.0 INCHES FROM NORTHWEST MEXICO INTO SOUTHERN
AZ...SOUTHERN CA... AND FAR SOUTHERN NV ASSOCIATED WITH THE FAIRLY
WELL DEFINED UPPER LOW OVER THE GULF OF CALIFORNIA THAT WILL BE
MOVING NORTHWESTWARD OFF THE NORTHERN BAJA AND SOUTHERN CA COASTS.
WITH POTENTIAL FOR CONVECTION TO AGAIN ENHANCE TO THE NORTH OF
THIS CIRCULATION AND THE CIRCULATION AND ASSOCIATED HIGH PW AXIS
PUSHING INTO OR CLOSER TO THE SOUTHWEST...THERE MAY BE ISOLATED
RUNOFF ISSUES AS INCREASING MONSOONAL ACTIVITY AFFECTS SOUTHERN AZ
INTO SOUTHEAST CALIFORNIA THIS PERIOD.

HURLEY
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