Quantitative Precipitation Forecast
Issued by NWS

Current Version | Previous Version | Graphics & Text | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
000
FOUS30 KWBC 030122
QPFERD

EXCESSIVE RAINFALL DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
822 PM EST TUE FEB 02 2016

...VALID 01Z WED FEB 03 2016 - 12Z WED FEB 03 2016...
...REFERENCE AWIPS GRAPHIC UNDER...DAY 1 EXCESSIVE RAINFALL...


SLIGHT RISK OF RAINFALL EXCEEDING FFG TO THE RIGHT OF A LINE FROM
10 SE HEZ 25 NE GWO 20 SW EHR 15 NNW BAK 25 N DAY 10 WSW 4I3
UNI 35 W LNP 15 SSW TYS 1A5 20 W MRN 15 ENE FQD 25 WSW AND
10 NE RYY 35 NNE GZH 15 WNW HSA 10 ESE BTR 10 SE HEZ.



OH VALLEY---TN VALLEY---SOUTHERN APPALACHIANS INTO THE CENTRAL
GULF COASTAL REGION

0100 UTC UPDATE...UPDATED THE PREVIOUS DAY 1 EXCESSIVE RAINFALL
OUTLOOK BASED ON THE LATEST RADAR TRENDS...ALONG WITH LATEST CAM
GUIDANCE (INCLUDING HRRR/EXPERIMENTAL HRRR). ALSO CONSIDERED THE
LATEST (18Z) SSEO 40KM NEIGHBORHOOD PROBABILITIES OF 3 AND 6
HOURLY QPF EXCEEDING THE CURRENT FFG...WHICH SHOWS A FAIRLY LARGE
SWATH OF 30-50% PROBABILITIES FROM CENTRAL-NORTHEAST MS INTO
WESTERN-CENTRAL TN AND NORTHERN AL THIS EVENING AND OVERNIGHT.

850-700 MB MOISTURE FLUX ANOMALIES WITHIN THE WARM SECTOR ARE
BETWEEN 4-5 STANDARD DEVIATIONS ABOVE NORMAL WITHIN THE OUTLOOK
AREA PER BOTH THE SREF AND GEFS...WITH PWS OVER 2.5 STANDARD
DEVIATIONS ABOVE NORMAL OR OVER THE 90TH PERCENTILE. THE OBSERVED
1.47" PW AT KBNA PER THE 00Z 02/03 RAOB IN FACT WOULD BE AT OR
NEAR A RECORD FOR FEBRUARY PER THE SPC SOUNDING CLIMATOLOGY PAGE.
WIND PROFILES REMAIN FAVORABLE FOR TRAINING CELLS THIS EVENING AND
AT LEAST THROUGH THE EARLY PORTION OF THE OVERNIGHT...WITH THE SSW
850 MB FLOW OF 60-75 KTS PER THE OBSERVED VPWS BECOMING MORE
PARALLEL TO THE MEAN 850-300 MB WIND PRIOR TO THE COLD FRONTAL
PASSAGE. BROAD-SCALE...ALONG-STREAM QG FORCING WILL REMAIN ROBUST
AHEAD OF THE MID-UPPER LEVEL TROUGH...WITH AN ELONGATED AREA OF
FAVORABLE UPPER LEVEL DIVERGENCE AND DIFFLUENCE WITHIN THE
ELONGATED WARM CONVEYOR BELT (WCB) AHEAD OF THE SURFACE COLD
FRONT. THE ONE POTENTIAL LIMITING FACTOR...AT LEAST IN TERMS OF
SHORT TERM RAINFALL RATES OVERNIGHT (1-3 HOURLY)...WILL BE THE
REDUCTION IN DEEP-LAYER INSTABILITY. THE LATEST SPC MESOANALYSIS
SHOWS BOTH THE MU AND MIXED LAYER CAPES ON THE DOWNWARD TREND OVER
THE PAST COUPLE OF HOURS...SUPPORTING THE MOST RECENT
ARW...HRRR... AND RAP GUIDANCE. WHILE THIS WOULD SUGGEST THE
THREAT BECOMING MORE CONFINED ACROSS THE SOUTHERN PORTION OF THE
CURRENT OUTLOOK AREA (TN-MS-AL)...THE MUCH LOWER 1/3/6 HOURLY FFG
OVER THE LOWER OH VALLEY KY WOULD SUPPORT KEEPING THE SLIGHT RISK
OVER THESE AREAS AS WELL.


HURLEY

PREVIOUS DISCUSSION BELOW...


1800 UTC UPDATE...

THE PREVIOUS EXCESSIVE RAINFALL POTENTIAL OUTLOOK WAS ADJUSTED
SLIGHTLY WESTWARD OVER THE LOWER OH VALLEY AND LOWER TN VALLEY TO
ACCOUNT FOR THE MODEL CONSENSUS FOR A FARTHER WESTWARD INITIATION
OF CONVECTION ALONG AND AHEAD OF THE EASTWARD MOVING FRONT ACROSS
THESE AREAS EARLY THIS PERIOD.  THE WESTWARD SHIFT WAS MOST
EMPHATIC IN THE HI RES ARW AND NMMB.  GIVEN THE CONVERGENCE IN THE
1200 UTC BASED GUIDANCE ON THE FARTHER WESTWARD INITIATION
SOLUTION---THIS WAS FOLLOWED IN THE LATEST DAY 1 QPF AND EXCESSIVE
RAINFALL POTENTIAL OUTLOOK THROUGH 1200 UTC WED FEB 3.  TRAINING
OF CELLS IN A SOUTH TO NORTH DIRECTION POSSIBLE IN THE AXIS OF
MUCH ABOVE AVERAGE PW VALUE EXPECTED ALONG AND AHEAD OF THIS
FRONT...WITH 1-2" TOTALS IN A FEW HOURS POSSIBLE WHERE TRAINING
OCCURS.  ENHANCED UPSLOPE INTO HIGHER TERRAIN OF THE SOUTHERN
APPALACHIANS WILL ALSO SUPPORT ISOLATED VERY HEAVY TOTALS IN THE
2-5"+ RANGE FROM FAR UPSTATE SC INTO FAR SOUTHWESTERN NC.

ORAVEC
$$




USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.