EXCESSIVE RAINFALL DISCUSSION
NWS HYDROMETEOROLOGICAL PREDICTION CENTER CAMP SPRINGS MD
228 AM EDT TUE MAY 03 2011
 
...VALID 06Z TUE MAY 03 2011 - 12Z WED MAY 04 2011...
...REFERENCE AWIPS GRAPHIC UNDER...DAY 1 EXCESSIVE RAINFALL...
 

SLIGHT RISK OF RAINFALL EXCEEDING FFG TO THE RIGHT OF A LINE FROM
CWTN 30 ESE CWST 45 SW FVE 50 NNW MLT 15 WSW GNR 35 NE BML
10 W HIE 20 NW 1P1 10 S RUT 15 SSW RUT 10 NNW SCH 35 WSW SCH
30 SSE BGM 15 ESE SEG 25 NNE HGR 30 ENE CBE JST FIG 25 ESE BFD
30 NW ELZ 25 SSW CWQP ART 25 SE OGS 20 S CWBZ 15 WSW CWBS CWTN.

SLIGHT RISK OF RAINFALL EXCEEDING FFG TO THE RIGHT OF A LINE FROM
20 SE SGH 20 SSE LUK 10 SSE LOU 30 WNW BWG 10 SSW CKV MKL
10 N OLV 10 SSE HKA 20 NNE CGI MVN 15 WSW EYE 15 WSW AOH
15 NW MFD MFD 20 SE SGH.

MODERATE RISK OF RAINFALL EXCEEDING FFG TO THE RIGHT OF A LINE
FROM
CWHY 15 SSW CWQH 25 S CWHY MVL 15 SSE BTV 25 SE SLK 35 SSW SLK
10 NE SLK CWIZ CWHY.

 
OH VALLEY...
THRU EARLY TUES...AREA OF POST FRONTAL RAINS AND A FEW EMBDD TSTMS
WILL CONTINUE TO LIFT NEWD ACRS THE REGION AHEAD OF UPR TROF
PUSHING ENEWD FROM THE SRN PLAINS.  MODEST SWLY FLOW OF MSTR WITH
PWS BETWEEN 1.25 AND 1.5 INCHES WILL BE TAPPED BY GRADUAL SHEARING
UPR TROF AND BROAD RIGHT ENTRANCE REGION OF UPR JET.  LACK OF
SIGNIFICANT INSTABILITY SHOULD KEEP GENL RAINFALL AMOUNTS BETWEEN
.50 TO .75 INCHES ACRS THE REGION..THOUGH SOME ISOLD 6 HR AMOUNTS
IN EXCESS OF AN INCH ARE PSBL.  EXISTING FF GUIDANCE VALUES ARE AS
LOW AS .25 INCH IN 3 HRS ACRS PARTS OF THE OUTLOOK AREA..SO THE
ADDITIONAL RAINS WHILE NOT EXTREME ARE STILL LIKELY TO CAUSE
ADDITIONAL RUNOFF PROBLEMS THRU EARLY TUES AT WHICH TIME PCPN
SHOULD GRADUALLY DIMINISH FROM WEST TO EAST.

NE...
SECOND AREA OF FLOODING CONCERNS IS ACRS THE NE AS MODELS CONTINUE
TO SHOW DECENT AGREEMENT IN GRADUALLY PHASING SRN STREAM UPR TROF
PUSHING EWD FROM THE SRN PLAINS WITH NRN STREAM TROF MOVING MORE
SLOWLY THRU THE WRN GT LAKES/MIDWEST.  LOW PRES IS EXPECTED TO
INTENSIFY ACRS THE NRN MID ATLC REGION LATER TUE WHERE IT WILL
LIFT MORE SLOWLY NWD TOWARD NEW ENGLAND BY WED MRNG AS UPR TROF
TRENDS TOWARD CLOSING OFF OVER THE ERN GT LAKES.  THIS SHOULD HELP
FOCUS THE MORE SIGNIFICANT RAINS ACRS UPSTATE NY/NRN VT AS LOW
LEVEL JET STRENGTHENS INTO THE ASSOCD FRONTAL BNDRY...WHICH IS
EXPECTED TO MOVE MORE SLOWLY THRU THE REGION TUES NIGHT.  COULD
NOT RULE OUT SOME EMBDD CONVECTIVE CELLS AS AREA OF WEAK
INSTABILITY WORKS NWD INTO THE REGION TUES NIGHT..WHICH COULD HELP
SUPPORT SOME ISOLD HEAVIER CONVECTION.  OTHERWISE..EXPECT A LONGER
DURATION RAINFALL EVENT WITH STORM TOTAL AMOUNTS OF 1 TO 2 INCH
AMOUNTS FROM NE PA NWD INTO UPSTATE NY INTO NW MAINE.  INDICATED A
MDT RISK OVER PORTIONS OF NE NY/NRN VT IN RESPONSE WHERE
COMBINATION OF EXPECTED HEAVIEST RAINS COINCIDE WITH RATHER LOW
FFG VALUES WITH SLIGHT RISK EXTENDING SWD INTO CNTL PA. 

SULLIVAN
A$$