Quantitative Precipitation Forecast
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FOUS30 KWBC 271849
QPFERD

EXCESSIVE RAINFALL DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
249 PM EDT FRI MAY 27 2016

...VALID 21Z FRI MAY 27 2016 - 12Z SAT MAY 28 2016...
...REFERENCE AWIPS GRAPHIC UNDER...DAY 1 EXCESSIVE RAINFALL...


SLIGHT RISK OF RAINFALL EXCEEDING FFG TO THE RIGHT OF A LINE FROM
20 SW JEF 20 SW SZL 20 SE OJC 25 SSW IXD UKL 30 S EMP 15 NE AAO
10 NW EWK 15 S SLN 20 S CNK 30 NW BIE 10 ENE LNK 10 ESE OFF
15 ESE CSQ 20 ESE CNC 20 SSW MQB 10 SSW PPQ 45 WNW SUS 10 NE JEF
20 SW JEF.

SLIGHT RISK OF RAINFALL EXCEEDING FFG TO THE RIGHT OF A LINE FROM
20 S ELD 10 NW SGT 10 SSW JBR 15 SW BYH 10 WSW NQA 45 S UTA
15 SSW HEZ 7R4 10 WSW KVNP 35 WSW KCRH 20 SE KGVX 10 SW KBQX
15 NW RKP 50 N RBO 50 SE SSF 45 ESE SSF 25 W 3T5 20 WSW OCH
20 SSE SHV 20 S ELD.

MODERATE RISK OF RAINFALL EXCEEDING FFG TO THE RIGHT OF A LINE FROM
10 N CXO 20 WNW JAS 25 NE JAS 10 NNE POE 15 WSW ACP 10 ENE CWF
10 NW 7R5 20 S BPT GLS LBX 10 W PSX 30 NNW VCT 3T5 30 ENE 11R
10 N CXO.


1900 UTC UPDATE

MID TO UPPER TX COAST INTO WESTERN TO CENTRAL LA AND SOUTHEAST AR.

CHANGES TO THE PREVIOUS EXCESSIVE RAINFALL POTENTIAL OUTLOOK WERE
TO SUPPRESS THE RISK AXIS OVER SOUTHEAST TX TO THE IMMEDIATE
CENTRAL TO UPPER TX COAST INTO CENTRAL TO NORTHERN LA AND
SOUTHEAST AR.  WE CONTINUE TO RELY MORE ON THE HRRR FOR CONVECTIVE
DETAILS AS IT APPEARS TO HAVE A BETTER HANDLE AT THE MOMENT.  THE
LATEST HI RES ARW WAS TOO FAR TO THE NORTH---ALTHOUGH IT DID SHOW
CONTINUED POTENTIAL FOR HEAVY RAINS.   CURRENT SURFACE ANALYSIS
CONTINUES TO SHOW THE WELL DEFINED OUTFLOW BOUNDARY OVER SOUTHEAST
TX WHICH REMAINS THE FOCUS FOR ADDITIONAL CONVECTION.  EXPECT THE
CONVECTION TO REMAIN ACTIVE ALONG AND JUST NORTH OF THE
BOUNDARY---WITH THIS CONVECTION PUSHING SOUTHEAST TOWARD THE MID
TO UPPER TX COAST AND INTO LARGE PORTIONS OF LA.  RAINFALL TOTALS
OF 1-3" PER HOUR AND TOTALS OVER 5-8 INCHES POSSIBLE ALONG THIS
LINE WHERE A PERIOD OF TRAINING IS POSSIBLE LATE AFTERNOON INTO
EARLY EVENING.  PLEASE SEE WPC`S MESOSCALE PRECIPITATION
DISCUSSION #0249 VALID TO APPROXIMATELY 2030 UTC FOR ADDITIONAL
DETAILS

ACROSS EASTERN KS INTO NORTHERN MO---THE MODERATE RISK AREA WAS
REMOVED GIVEN RISING FFG VALUES AND LATEST GUIDANCE SHOWING
ACTIVITY POSSIBLY ENHANCING TO THE EAST OF THE LOWER FFG VALUES.


1500 UTC UPDATE

CENTRAL TO SOUTHEAST TX INTO THE LOWER MS VALLEY

SOME SIGNIFICANT CHANGES MADE TO THE PREVIOUS EXCESSIVE RAINFALL
POTENTIAL OUTLOOK FOR THE DAY 1 TIME PERIOD.  THE BROAD RISK AREA
WAS SEPARATED INTO TWO AREAS AS PER LATEST RADAR TRENDS AND HI RES
SHORT TERM GUIDANCE.  THE SOUTHERN RISK AREA WAS EXPANDED WESTWARD
INTO CENTRAL TX TO ACCOUNT FOR CONVECTION THAT CONTINUES TO FOCUS
ALONG AND JUST NORTH OF A WELL DEFINED OUTFLOW BOUNDARY OVER
CENTRAL TO SOUTHEAST TX.  MOIST SOUTH SOUTHWESTERLY LOW LEVEL FLOW
INTO THIS BOUNDARY WILL CONTINUE TO SUPPORT POTENTIAL FOR
CONVECTION TO REFORM ON THE WESTERN PORTION OF THE OUTFLOW AND
TRAIN DOWNSTREAM.  THIS MAY LIMIT THE NORTHWARD PUSH OF
PRECIP---WITH THIS THE PRIMARY REASON THE THREAT AREA WAS SPLIT
INTO TWO AREAS.  THE HRR---HRRP AND HRRR EXPERIMENTAL SEEM TO HAVE
THE BEST HANDLE ON THIS CURRENT ACTIVITY---ALL SUGGESTING THE
HEAVY RAIN THREAT WILL CONTINUE INTO THIS AFTERNOON ALONG AND
NORTH OF THIS BOUNDARY---BUT REMAIN CENTERED FARTHER TO THE SOUTH
THAN SOME OF THE OTHER GUIDANCE IS SHOWING.  TOWARD THE END OF
THIS FORECAST PERIOD---EARLY MORNING HOURS OF
SATURDAY---CONVECTION MAY PUSH SOUTHWARD BACK INTO AREAS WHERE THE
FFG VALUES HAVE LOWERED SIGNIFICANTLY OVER SOUTHEAST TX.  FOR THIS
REASON---THE PREVIOUS MODERATE RISK AREA WAS PUSHED SOUTHWARD AND
ANOTHER MODERATE AREA WAS ADDED BETWEEN WACO AND BROWNWOOD FOR
CURRENT ACTIVITY AND LOW FFG VALUES.

OVER EASTERN KS AND NORTHERN MO...

THE MODERATE RISK AREA WAS EXPANDED WESTWARD INTO NORTHEAST KS TO
COVER THE LOWER FFG VALUES.  MODELS CONTINUE TO SUGGEST HEAVY RAIN
POTENTIAL LATER THIS PERIOD...AFTERNOON INTO THE OVERNIGHT HOURS
TO THE NORTHEAST OF THE EJECTING CENTRAL HIGH PLAINS CLOSED LOW.
STILL SOME UNCERTAINTIES HOW ANY ORGANIZED ACTIVITY TO THE SOUTH
WILL DISRUPT THIS POTENTIAL---BUT WITH FFG VALUES SO LOW---BELIEVE
THE RUNOFF THREAT WILL REMAIN OVER EASTERN KS INTO NORTHERN MO.

ORAVEC

PREVIOUS DISCUSSION

...ERN KS/SE NEB/MO/AR/LA/ERN TX...

A RATHER LARGE SLIGHT RISK AREA IS DEPICTED FOR DAY ONE AS ANOTHER
DAY OF ACTIVE WEATHER IS EXPECTED ACRS MUCH OF THE CNTL U.S. IN
ADVANCE OF A SLOW MOVING UPR TROF LIFTING NEWD OUT OF THE CNTL/SRN
ROCKIES.    VERY MOIST UNSTABLE AIRMASS AHEAD OF THIS FEATURE
COMBINED WITH HEIGHT FALLS AND DIFFLUENT FLOW ALOFT WILL ONCE
AHEAD LEAD TO NUMEROUS SHOWERS/TSTMS FROM THE SRN/CNTL PLAINS AND
EXTENDING EAST OF THOSE AREAS.  WHILE THE GLOBAL MODELS SHOW
REASONABLY SIMILAR HANDLING OF THE UPR LOW/TROF...MODELS CONTINUE
TO STRUGGLE SHOWING ANY CONSISTENCY/AGREEMENT WITH CONVECTIVE
DEVELOPMENT AND THIS INCLUDES MOST OF THE HI RES CONVECTIVE
ALLOWING MODELS AS WELL.  THIS LEADS TO RATHER LOW CONFIDENCE IN
TIMING/PLACEMENT OF HEAVIER PCPN...THOUGH THERMAL/MSTR
CONSIDERATIONS WITH PWS WELL IN EXCESS OF 1.75 INCHES ACRS THE SRN
PLAINS INTO THE MID MS VALLEY WOULD GENLY SUPPORT CONTINUED THREAT
OF ORGANIZED HEAVY TO EXCESSIVE RAINS..FROM PARTS OF THE MID MS
VALLEY SWD THRU ARKANSAS/WRN LA AND ERN TX.  HOW REMNANT OUTFLOW
BNDRIES FROM OVERNIGHT MCS ACTIVITY OVER SRN TX AS WELL AS CNTL KS
PLAY OUT THIS MRNG IS QUITE THE CHALLENGE AS AGAIN HI RES GUIDANCE
INCLUDING MULTIPLE HRRR RUNS HAVE NOT DONE PARTICULARLY WELL.
HOWEVER..MOST SUGGEST A SLIGHT EWD FOCUS FROM MOST OF THE GLOBAL
GUIDANCE FOR SUBSEQUENT DEVELOPMENT TODAY/TONIGHT ACRS THE SOUTH
AND THIS IDEA WAS GENLY FOLLOWED.   THE THREAT OF EXCESSIVE RAINS
WILL BE FUELED BY 40 KT SLY 85H FLOW AND GREATER THAN 1.75 INCH
PROVIDING STG MSTR FLUX WELL AHEAD OF THE UPR TROF.  EXPECT SOME
SHORT TERM RAINFALL RATES OF 1 TO 2 INCHES THRU PARTS OF ERN KS/SE
NEB AND MO PRIMARILY FRI AFTN/EVE AS MAIN HEIGHT FALLS WORK EWD
AND HELP DESTABILIZE THE REGION AHEAD OF THE ASSOCD COLD
FRONT...WHILE HEAVIER AMOUNTS ARE PSBL FARTHER SOUTH ACRS THE
ARKLATEX IN PROXIMITY TO HIER MSTR AND DEEPER LAYERED SSWLY FLOW
THAT COULD PROMOTE TRAINING.  EARLIER HEAVY RAINS HAVE LOWERED FFG
VALUES SIGNIFICANTLY ACRS PARTS OF NE KS/MO AND ERN TX SO THAT IT
WON`T TAKE MUCH ADDITIONAL RAINS ACRS THOSE AREAS TO EXACERBATE
RUNOFF PROBLEMS.


SULLIVAN
$$





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