Quantitative Precipitation Forecast
Issued by NWS

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FOUS30 KWBC 191219
QPFERD

EXCESSIVE RAINFALL DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
818 AM EDT TUE MAY 19 2015

...VALID 15Z TUE MAY 19 2015 - 12Z WED MAY 20 2015...
...REFERENCE AWIPS GRAPHIC UNDER...DAY 1 EXCESSIVE RAINFALL...


SLIGHT RISK OF RAINFALL EXCEEDING FFG TO THE RIGHT OF A LINE FROM
15 E VDW 25 NNE GXY 15 ENE DEN 15 SSW LIC 15 SE PUB 25 SSE TAD
30 NNE SKX 25 NW VTP 20 NE MYP CCU 20 ESE 20V 30 SW PUM 15 E VDW.

SLIGHT RISK OF RAINFALL EXCEEDING FFG TO THE RIGHT OF A LINE FROM
25 ENE PYX 35 WNW JWG 15 ESE GOK 25 WSW OKM JSV 30 SE FSM
30 NNE TXK 30 E OSA 20 WSW 3T1 15 ENE JWY 10 WSW MWL 35 W RPH
60 S CDS 35 ESE PVW 30 NNW PVW 30 WNW AMA 15 NNW DUX 30 SSW GUY
25 ENE PYX.


...CENTRAL ROCKIES/FOOTHILLS/ADJACENT HIGH PLAINS...

NEGATIVELY TILTED HEIGHT FALLS WILL BE PUSHING OUT OF THE CENTRAL
ROCKIES TODAY AND INTO THE SOUTHERN TO CENTRAL HIGH PLAINS.
WIDESPREAD MODERATE TO HEAVY PRECIPITATION TOTALS LIKELY AHEAD OF
THESE HEIGHT FALLS IN THE LEE OF THE CENTRAL ROCKIES IN A REGION
OF WELL DEFINED UPPER DIFFLUENCE---STRENGTHENING SOUTHEASTERLY TO
EASTERLY LOW LEVEL FLOW IN AN AXIS OF ABOVE AVERAGE PW VALUES.
THE THREAT AREA IS EXPECTED TO BE WHERE UPSLOPE FLOW COMES INTO
THE FOOTHILLS AND FRONT RANGE.  AFTER MORNING SYNOPTIC RAINS HAVE
MOVED DOWNSTREAM...LAPSE RATES START TO STEEPEN LATER TODAY INTO
TONIGHT TO 7-8 DEG C/KM.  SHOWERS THAT DEVELOP WOULD HAVE
POTENTIAL TO PRODUCE ISOLATED HEAVY DOWNPOURS IN AN AREA THAT HAS
RECEIVED RECENT RAINS.  THE RISK AREA COVERS MOST OF THE LOWER
FLASH FLOOD GUIDANCE VALUES OF 1-1.5 INCHES OF RAIN IN 6 HOURS.

...TEXAS PANHANDLE ACROSS NORTHERN TEXAS/SOUTHERN OKLAHOMA...

CLUSTERS OF SHOWERS/THUNDERSTORMS HAVE DEVELOPED WITH ONE CLUSTER
MOVING EAST FROM EASTERN NM.  PERSISTENT LOW-MID LEVEL MOISTURE
CONVERGENCE...UPPER DIVERGENCE... AND LOW LEVEL WARM ADVECTION
SUPPORTS SHOWERS/STORMS CROSSING THE TEXAS PANHANDLE THIS MORNING
DOWNSTREAM INTO SOUTHERN OK AND NORTH TEXAS.  AN AREA OF
PRECIPITABLE WATER VALUES OF 1.75-2 INCHES FCST ACROSS NORTH TEXAS
TO SOUTHERN OK SUPPLIES MOISTURE FOR THE PRECIPITATION.  TIMING
AND AXIS OF OF CONVECTION IS VARYING IN THE MODELS---BUT THERE IS
STRONG SIGNAL FOR HEAVY TO LOCALLY EXCESSIVE AMOUNTS THIS PERIOD
IN THE 0-06Z GFS/CANADIAN GLOBAL/CANADIAN REGIONAL/UKMET GEM/WRF
ARW AND ARW PARALLEL.  WIDESPREAD TOTALS OF 1-2" POSSIBLE WITH
LOCALIZED AMOUNTS IN THE 2-4"+ RANGE WHERE SLOW MOVEMENT OR
TRAINING OF CONVECTION OCCURS.

PETERSEN
$$




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