Quantitative Precipitation Forecast
Issued by NWS

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000
FOUS30 KWBC 251408
QPFERD

EXCESSIVE RAINFALL DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
1007 AM EDT MON JUL 25 2016

...VALID 15Z MON JUL 25 2016 - 12Z TUE JUL 26 2016...
...REFERENCE AWIPS GRAPHIC UNDER...DAY 1 EXCESSIVE RAINFALL...


SLIGHT RISK OF RAINFALL EXCEEDING FFG TO THE RIGHT OF A LINE FROM
25 N ARG 40 NW SRC 10 WNW FSM 15 E SWO 15 N WLD 45 SSE IXD
10 E AIZ 40 SSW FAM 25 N ARG.


SOUTHEAST KS...NORTHEAST OK...SOUTHERN MO...NORTHERN AR
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

INCLUDED A "SLIGHT RISK" AREA OVER THIS REGION TO ACCOUNT FOR THE
CURRENT WIDESPREAD ACTIVITY ALONG AND SOUTH OF THE SURFACE FRONT.
THE OUTLOOK IS IN AN AREA OF WEAK UPPER LEVEL DIFFLUENCE...WHERE
THE ACTIVITY IS FEEDING OFF THE FAVORABLE THERMODYNAMIC
ENVIRONMENT WITH OBSERVED PW VALUES OF 2-2.25" AND MUCAPES BETWEEN
1000-2000 J/KG. OVER TIME TODAY...THE LIMITING FACTOR IN TERMS OF
MAINTAINING THE  ORGANIZATION AND INTENSITY (SHORT-TERM RAINFALL
RATES) CURRENTLY OBSERVED WILL BE THE WEAKENING LOW LEVEL INFLOW
AND WEAK (<20 KTS) 0-6KM BULK SHEAR AS THE CONVECTIVE CLUSTERS
CONTINUE TO DROP SOUTHWARD. NEVERTHELESS...DESPITE THE LIKELY
TREND TOWARD A MORE PULSE-TYPE CHARACTERISTIC WITH THE HEAVIEST
RAIN CORES...THE WEAK FLOW ALOFT AND THUS SLOW PROPAGATION WILL
ALLOW FOR SOME CELL MERGERS AND TRAINING OF CONVECTION BEFORE THE
INSTABILITY IS EXHAUSTED. AS A RESULT...SHORT-TERM FFG VALUES
(2.5-3.0" IN 3 HOURS) COULD CERTAINLY BE MET OR EXCEEDED
UNDERNEATH THE HEAVIEST CORES...AT LEAST THROUGH  20-22Z PER THE
LATEST (06Z) SSEO-BASED 40 KM NEIGHBORHOOD PROBABILITIES.


SOUTHERN HIGH PLAINS
~~~~~~~~~~~~~~~~~~~~

SOMEWHAT ANOMALOUS MOISTURE ACROSS THE REGION (1-2 SIGMAS ABOVE
THE MEAN FOR LATE JULY) ALONG WITH DAYTIME HEATING ARE EXPECTED TO
HELP FIRE AFTERNOON AND EVENING CONVECTION.  THUNDERSTORMS ROLLING
OUT OF NORTHEAST NM INTO THE TX PANHANDLE COULD BECOME
PROBLEMATIC.  LOW-LEVEL INFLOW INCREASES TO 25+ KTS WHILE
PRECIPITABLE WATER VALUES (ADJUSTED FOR SEA LEVEL >= 1.5") AND
CAPES/INSTABILITY (2000+ J/KG) REMAIN SUFFICIENT FOR BROADER SCALE
HEAVY RAIN ISSUES.  THE MESOSCALE GUIDANCE HAS A SIGNAL FOR LOCAL
AMOUNTS IN THE 3-5" RANGE.  RECENT CONVECTION OVERNIGHT IS
EXPECTED TO SOMEWHAT LOWER FLASH FLOOD GUIDANCE VALUES/PARTIALLY
SATURATE SOILS.  THE LIMITING FACTOR FOR A BROAD SCALE THREAT IS
THE QUICK VEERING OF THE LOW-LEVEL INFLOW SEEN IN THE GUIDANCE.
THE 00Z ECMWF THREW A MONKEY WRENCH IN THE SITUATION BY NOT HAVING
THIS POTENTIAL THUNDERSTORM COMPLEX, INCREASING UNCERTAINTY.
THOUGHT IT PRUDENT TO HAVE A SEE TEXT/MARGINAL AREA FOR NORTHEAST
NM AS WELL AS THE TX/OK PANHANDLES AND POSSIBLY WESTERN OK.


OH & TN VALLEYS/NORTHEAST
~~~~~~~~~~~~~~~~~~~~~~~~~

THUNDERSTORMS ARE EXPECTED NEAR AND AHEAD OF A PROGRESSIVE COLD
FRONT.  WARM ADVECTION SHOWERS AND THUNDERSTORMS ACROSS SOUTHEAST
ONTARIO ARE SLATED TO MOVE EASTWARD INTO NY WITH NEW ACTIVITY
FORMING ACROSS NORTHERN AND SOUTHERN NEW ENGLAND WITH TIME.
MOISTURE ANOMALIES ARE AROUND TWO SIGMAS ABOVE THE MEAN FOR LATE
JULY ACROSS NEW ENGLAND.  COMBINE THIS WITH NEARLY UNIDIRECTIONAL
WESTERLY FLOW AND DAYTIME HEATING WHICH SHOULD PUSH CAPES INTO THE
1500-2000 J/KG RANGE, SHORT BOUTS OF CELL TRAINING ARE POSSIBLE
WITH HOURLY RAIN RATES UP TO 2".  THE MESOSCALE GUIDANCE
ADVERTISES LOCAL AMOUNTS IN THE 2-4" RANGE ACROSS NORTHERN AND
SOUTHERN NEW ENGLAND.  CONSIDERING SLIGHTLY MORE FAVORABLE THAN
UNFAVORABLE FOR HEAVY RAINFALL HERE, FIGURED A SEE TEXT/MARGINAL
AREA WAS THE BEST COURSE OF ACTION.

HURLEY/ROTH
$$




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