Quantitative Precipitation Forecast
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000
FOUS30 KWBC 310100
QPFERD

EXCESSIVE RAINFALL DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
859 PM EDT TUE AUG 30 2016

...VALID 01Z WED AUG 31 2016 - 12Z WED AUG 31 2016...
...REFERENCE AWIPS GRAPHIC UNDER...DAY 1 EXCESSIVE RAINFALL...


MARGINAL RISK OF RAINFALL EXCEEDING FFG TO THE RIGHT OF A LINE FROM
40 ESE PIL 15 SSE MMMA 25 SW MMRX 60 NE MMMY.

MARGINAL RISK OF RAINFALL EXCEEDING FFG TO THE RIGHT OF A LINE FROM
95 SE DUG 60 SSW DMN 35 N SVC 50 W 4CR 25 SSE SKX 25 SSE VTP
15 ENE VTP 30 NNE VTP 30 SW FCS 25 WSW AFF 10 WNW MNH 25 WNW LIC
LIC 25 ENE LIC 10 NW ITR 10 WSW GLD 15 ESE GLD 25 WNW HLC
20 SSW HDE 25 NNW HJH 25 SSE LWD 15 W BMI OKK 30 ESE FWA FDY
15 ENE MNN TZR 35 SSE BAK 20 ENE BLV 15 ENE BLV 15 W VIH
35 NE JLN 20 SSW BVO LTS 20 WSW SNK 25 W E29 35 N DRT 30 SE MMPG
30 NNW LRD 15 NNE LRD 20 NNW HBV 15 NW ALI 20 NNE ALI 15 SW VCT
10 WNW PSX 20 NNW KBQX 10 SSE KBQX 25 NW KVAF.

MARGINAL RISK OF RAINFALL EXCEEDING FFG TO THE RIGHT OF A LINE FROM
120 W PIE 45 SSW CTY 30 SSW SGJ 80 NE TTS.

SLIGHT RISK OF RAINFALL EXCEEDING FFG TO THE RIGHT OF A LINE FROM
25 NNE ALM 15 SE LVS 50 W CVS 15 E DHT 15 NNW PYX 10 S HHF
35 W LBB 40 S ODO 40 SE E38 45 S MRF 45 WNW MRF 40 E ELP
25 NNE ALM.

SLIGHT RISK OF RAINFALL EXCEEDING FFG TO THE RIGHT OF A LINE FROM
40 SSE BIE 25 SSE FNB 20 SE STJ 35 SW CDJ 35 N SZL 10 N SZL
15 SW SZL 50 SW SZL 55 N JLN 40 E CNU 25 ESE CNU PPF 25 ENE WLD
25 SW ICT GBD 20 WNW GBD 20 SSW HYS 15 W HYS 20 NNW HYS 35 N RSL
15 W CNK 20 NE CNK 25 ENE CNK 40 SSE BIE.

SLIGHT RISK OF RAINFALL EXCEEDING FFG TO THE RIGHT OF A LINE FROM
25 E HST 30 E MTH 15 SE NQX 25 WSW KEY 55 WNW KEY.

SLIGHT RISK OF RAINFALL EXCEEDING FFG TO THE RIGHT OF A LINE FROM
45 W SRQ 30 WNW PIE 10 WNW VVG 60 NE TTS.


0100 UTC UPDATE

ADJUSTMENTS MADE TO THE PREVIOUS EXCESSIVE RAINFALL POTENTIAL
OUTLOOK WERE BASED HEAVILY ON RADAR TRENDS FROM THE CENTRAL PLAINS
INTO THE MID MS VALLEY AND JUST NORTH OF THE OH VALLEY.  THE
PREVIOUS SLIGHT RISK AREA WAS DECREASED IN SIZE AND CONCENTRATED
WHERE CONVECTION REMAINS MOST ACTIVE OVER CENTRAL TO EASTERN KS
INTO WEST CENTRAL MO.  THE MARGINAL RISK AREA WAS SUPPRESSED
SOUTHWARD THROUGH THE MID MS VALLEY AND TO JUST NORTH OF THE OH
VALLEY.

OVER FL...WITH CONVECTION WANING AND LATEST HI RES GUIDANCE
SUGGESTING THE BEST POTENTIAL THROUGH 1200 UTC WEDNESDAY WILL BE
CONCENTRATED ALONG COASTAL SECTIONS OF SOUTHWEST AND SOUTHEAST
FL---THE MODERATE RISK WAS REMOVED FROM SOUTH FLORIDA---WITH A
SLIGHT RISK MAINTAINED.

COASTAL TX..THE SLIGHT RISK WAS REMOVED FROM COASTAL CENTRAL TO
SOUTH TX AS MOST ORGANIZED CONVECTION IS REMAINING OFFSHORE.  THE
MARGINAL RISK WAS ALSO SUPPRESSED SOUTHWARD.

ORAVEC

PREVIOUS DISCUSSION...

FLORIDA
~~~~~~~
THE TRACK OF T.D. #9 WILL CONTINUE INTO THE SOUTHEASTERN GULF OF
MEXICO BEFORE BECOMING A TROPICAL STORM DURING THE RECURVATURE
PROCESS TONIGHT AND WEDNESDAY MORNING. THIS WILL ALLOW FOR THE
CONTINUAL NORTHWARD PUSH OF 2-2.5" PRECIPITABLE WATER VALUES
ACROSS THE FL PENINSULA ON THE EAST TO NORTHEAST SIDE OF THE
CIRCULATION.  A CONVERGENCE BAND SETS UP OVER THE PENINSULA
BETWEEN THIS SYSTEM AND A NEW LOW OFFSHORE GA, ACTING AS A MORE
EFFECTIVE FOCUS FOR CONVECTION DURING DAYTIME HEATING (ROUGHLY
18Z-03Z).  GFS FORECASTS INDICATE 850 HPA INFLOW INCREASES TO
20-30 KTS WHILE SREF MEAN FIELDS INDICATE 2000 J/KG OF SURFACE
BASED CAPE.  WHEN COMBINED WITH EVACUATION ALOFT FROM AN UPPER LOW
TO THE NORTHEAST AND A POSSIBLE OUTFLOW JET FROM THE SLOWLY
DEVELOPING DEPRESSION, THE STAGE IS SET FOR WIDESPREAD MODERATE TO
HEAVY RAINS FOR CENTRAL TO SOUTH FLORIDA.  HIGH RESOLUTION
GUIDANCE IS VERY WET, SHOWING EITHER STRIPES OF 7"+ TOTALS, OR IN
THE CASE OF THE UNUSUALLY DRY NAM CONEST DUE TO ITS MORE WESTERLY
TRACK OF THE CYCLONE, LOCAL MAXIMA OF 5-7".  DUE TO THE STRONG
SIGNAL IN THE MESOSCALE GUIDANCE, AN UPGRADE TO A MODERATE RISK
WAS ADDED FOR PORTIONS OF THE PENINSULA SURROUNDING LAKE
OKEECHOBEE.  THIS WAS COORDINATED WITH THE MIAMI AND TAMPA FL
FORECAST OFFICES.


SOUTHERN AND CENTRAL PLAINS AND MIDWEST
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
MODERATELY STRONG UPSLOPE FLOW COMBINED WITH A MOIST AIRMASS AND A
NEARBY BOUNDARY AT 850 HPA IS EXPECTED TO CAUSE ANOTHER BOUT OF
HEAVY RAINS ACROSS PORTIONS OF WESTERN TX AND SOUTHEAST NM.  A
SLIGHT RISK OF EXCESSIVE RAINFALL HAS BEEN ADDED, AS THE GUIDANCE
SHOWS LOCAL MAXIMA OF 2-4" OVER SATURATED SOILS IN THIS AREA.
FROM THE CENTRAL PLAINS EAST-NORTHEAST, WEAK LOW-LEVEL INFLOW
SHOULD KEEP CONVECTION OF A PULSE NATURE, THOUGH SIGNIFICANT
MOISTURE COULD MAKE THE CELLS EFFICIENT RAINFALL-WISE.  THE
MESOSCALE GUIDANCE HAS A CONSISTENT SIGNAL FOR LOCAL AMOUNTS IN
THE 3-5" RANGE.  ANOTHER SLIGHT RISK OF EXCESSIVE RAINFALL WAS
ADDED FROM NORTHERN KS/SOUTHEAST NE EASTWARD INTO THE NORTHERN
IL/FAR NORTHWEST IN WHERE SOILS ARE PARTIALLY SATURATED FROM
RECENT RAINS.


WESTERN GULF COAST
~~~~~~~~~~~~~~~~~~
THE MID TO UPPER LEVEL CIRCULATION INITIALLY ALONG THE UPPER TX
COAST IS EXPECTED TO MOVE SOUTHWEST, WHICH EVENTUALLY WEAKENS THE
LOW-LEVEL INFLOW INTO SOUTHERN TX BY WEDNESDAY MORNING. THE AXIS
OF ABOVE AVERAGE PW VALUES IN THE EASTERLY INFLOW MAX TO THE NORTH
OF THIS CENTER WILL CONTINUE TO SUPPORT HEAVY RAINFALL POTENTIAL
ALONG THE IMMEDIATE MID TO LOWER TX COAST, WITH A POSSIBLE SPREAD
INLAND OF PROGRESSIVE CONVECTIVE CELLS DURING DAYTIME HEATING
WHICH WILL THEN SET OFF OUTFLOW BOUNDARIES TO SET RAIN WEST AND
NORTHWEST.  MODEL CONSENSUS IS FOR SIGNIFICANT PRECIPITATION TO
NOT TO MAKE IT VERY FAR INLAND.  A SMALL SLIGHT RISK OF EXCESSIVE
RAINFALL WAS PLACED ACROSS PORTIONS OF THE MIDDLE AND LOWER TX
COAST, WITH ITS NORTHWARD EXTENT COORDINATED WITH THE
HOUSTON/GALVESTON TX FORECAST OFFICE.

PEREIRA/ROTH
$$




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