Quantitative Precipitation Forecast
Issued by NWS

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FOUS30 KWBC 300100
QPFERD

EXCESSIVE RAINFALL DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
859 PM EDT SUN MAY 29 2016

...VALID 01Z MON MAY 30 2016 - 12Z MON MAY 30 2016...
...REFERENCE AWIPS GRAPHIC UNDER...DAY 1 EXCESSIVE RAINFALL...


SLIGHT RISK OF RAINFALL EXCEEDING FFG TO THE RIGHT OF A LINE FROM
15 S MQI 15 NE SUT 30 ENE CHS 20 WSW NBC 35 W OGB 20 NNE MTV
20 NE W99 35 N UNV 30 E BUF 15 ENE UCA 25 SE MSS 10 S CMRY
10 SW MVL VSF 10 SSW DXR 15 E CGE 15 E LFI 15 S MQI.

SLIGHT RISK OF RAINFALL EXCEEDING FFG TO THE RIGHT OF A LINE FROM
HHF 15 SSW OUN 20 NNW GVT 15 ENE AUS 35 SE COT 45 NW LRD
25 S DRT 45 W E29 40 ESE LBB 20 NNE CVN 15 WSW DUX HHF.


0100 UTC UPDATE

A BROAD SLIGHT RISK AREA CONTINUES THROUGH THE REMAINDER OF THE
DAY 1 PERIOD (12Z MON) FROM EASTERN SC NNE THROUGH THE MID
ATLANTIC AND INTO UPSTATE NY AND WESTERN NEW ENGLAND. THIS WAS TO
COVER THE EXPANDING AREA OF CONVECTION THAT HAS FORMED THIS
AFTERNOON/EARLY EVENING ACROSS THESE AREAS IN THE INCREASINGLY
UNSTABLE AIRMASS AHEAD OF THE COLD FRONT MOVING INTO THE GREAT
LAKES AND THE WARM FRONT RETREATING INTO NEW ENGLAND. WHILE FAR
REMOVED FROM TD BONNIE`S CIRCULATION...AN ELONGATED WARM CONVEYOR
BELT AND PLUME OF ANOMALOUSLY DEEP MOISTURE (PWS OF AT LEAST
1.50") HAVE EXPANDED WELL N-NE INTO THE NORTHEASTERN
CONUS...ENRICHING THE THERMODYNAMIC PROFILE AHEAD OF THE
APPROACHING FRONT. THE ATMOSPHERIC RIVER HAS ORIGINS FROM THE
EASTERN CARIBBEAN...WHICH IS NOTED ON THE SATELLITE TPW LOOPS
ALONG WITH THE 500-300 MB LAYER PW. DUE TO THE FAVORABLE
DEEP-LAYER MOISTURE...WEAK INSTABILITY (MUCAPES 500-1000 J/KG) IS
MORE THAN SUFFICIENT FOR RAINFALL RATES THAT WILL APPROACH OR IN
SOME AREAS EXCEED 1-3 HOURLY FFG.

CLOSER TO BONNIE`S CIRCULATION...HAVE MAINTAINED A SLIGHT RISK
AREA THROUGH 12Z AS WELL...ALTHOUGH THE AREA OF MORE WIDESPREAD
CONVECTION (COLDER CLOUD TOPS) IS FAIRLY COMPACT AT THIS POINT.

ACROSS THE MID SECTION OF THE NATION...BOTH THE GLOBAL AND
HIGH-RES GUIDANCE CONTINUE TO STRUGGLE WITH THE QPF WELL EAST OF
THE SOUTHWESTERN U.S. UPPER LOW. WEAK PERTURBATIONS WITHIN AN
OTHERWISE BROADLY DIFFLUENT FLOW ALOFT IS TRIGGERING TWO
CONCENTRATED AREAS OF CONVECTION EARLY THIS EVENING -- ONE
CENTERED ACROSS KS/NE AND THE OTHER ACROSS THE TX PANHANDLE. SEE
THE LATEST MESOSCALE PRECIPITATION DISCUSSIONS (MPDS) FOR FURTHER
SHORT-TERM DETAILS. OTHERWISE...THE MUCH OF THE HIGH RES
GUIDANCE...INCLUDING RECENT HRRR AND PARALLEL HRRR RUNS... FAVOR
THE TX PANHANDLE CONVECTION TO PROPAGATE SOUTHWARD INTO
WEST-CENTRAL TX. THEREFORE...THE ELONGATED SLIGHT RISK CONTINUES
N-S ACROSS TX.

HURLEY


PREVIOUS DISCUSSION


...COASTAL SC/EXTREME SRN NC COAST...


HEAVY TO EXCESSIVE RAIN THREAT WILL CONTINUE TO SPREAD NWD WITH
THE SLOW NWWD PROGRESSION OF TS BONNIE INTO SC.  BONNIE REMAINS
EMBDD WITHIN A LARGE NW-SE ORIENTED UPR SHEAR AXIS/TROF TO THE
SOUTH OF AN UPPER RIDGE OFF THE MID ATLC COAST AND WHILE THE
SYSTEM ITSELF WILL WEAKEN THIS PD..DEEP TROPICAL MSTR WITHIN THE
TROF AXIS WILL CONTINUE TO STREAM RAPIDLY NNWWD THRU THE MID ATLC
TOWARD THE NE.  THE APPROACH OF AN UPR TROF OVER THE GT
LAKES/MIDWEST WILL PROVIDE INCREASINGLY CONFLUENT 85H FLOW ACRS
THE MID ATLC REGION BY SUN NIGHT WHERE A PERIOD OF HEAVY RAINS
WITH EMBDD CONVECTION WILL BE PSBL WELL TO THE NORTH OF BONNIE.
SEVERAL HI RES MODEL RUNS SUPPORT A NARROW CORRIDOR OF 1 TO 2"+
RAINS FROM CNTL VA NEWD INTO SE PA AND NRN NJ WHICH ALSO HAS THE
SUPPORT OF THE 00Z UKMET AND HWRF.   MEANWHILE...HI RES MODELS
HAVE DONE A DECENT JOB WITH THE MAINTAINING A HEAVY RAIN CORE ON
THE WRN/SWRN SIDE OF BONNIE`S CIRC AND HAVE TENDED TO FAVOR THE
DEPICTION OF HEAVY RAIN AXIS ACRS SRN SC INTO CNTL SC WITH MID
LEVEL SHEAR AXIS PROVIDING WRN EXTENT OF THE HEAVIER RAINS.
ADDITIONAL RAINS THERE OF 2 TO 4 INCHES WITH PERHAPS ISOLD AMOUNTS
UP TO 6 INCHES...COULD LEAD TO A HEIGHTENED THREAT OF RUNOFF
PROBLEMS AND HENCE HAVE INDICATED A MDT RISK FOR THAT AREA NWD
INTO SCNTL NC. SEE THE LATEST NHC ADVISORIES FOR ADDITIONAL
INFORMATION ON THIS STORM.


...SRN PLAINS...

ADDITIONAL SHORTWAVE ENERGY/JET STREAK WILL BE EJECTING OUT ACRS
NRN MEX/NEW MEXICO INTO TX ON SUN.  STRENGTHENING SLY 85H FLOW
WILL ALLOW PWS TO INCREASE NWD ACRS NRN TX/OK EARLY SUN MRNG WHERE
LEFT EXIT REGION JET WILL HELP AID CONVECTIVE DEVELOPMENT AT START
OF THE PD ALONG OLD FRONTAL BNDRY THAT WILL CONTINUE TO BECOME
MORE DIFFUSE WITH TIME. ADDITIONAL STORMS ARE LIKELY TO DVLP ALONG
AND EAST OF DRY LINE SWD TOWARD THE BIG BEND AREA AND NRN MEX
DURING AFTN HEATING AND SLOWLY PROPAGATE EWD/SEWD INTO THE DEEPER
DOWNSTREAM MSTR  WHILE MODELS SHOW AN INCREASED HEAVY RAIN THREAT
ACRS PARTS OF THE REGION...THERE CONTINUES TO BE LARGE DIFFERENCES
WITH PLACEMENT ESPECIALLY LATITUDINAL-LY HENCE A RATHER BROAD
SLIGHT RISK OF EXCESSIVE RAINS HAS BEEN DEPICTED FROM THE NW/NRN
TX AND WRN OK SWD TOWARD CNTL TX.

SULLIVAN




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