Flash Flood Warning 20, NWS New York, NY

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE UPTON NY
1238 PM EDT FRI APR 27 2007

.SYNOPSIS...
A WARM FRONT HAS LIFTED ACROSS EASTERN LONG ISLAND THIS
MORNING...OTHERWISE THE FRONT WILL REMAIN JUST S OF NEW YORK CITY
THIS AFTERNOON. WAVES OF LOW PRESSURE RIPPLING ALONG THIS FRONT WILL
BRING HEAVY RAIN AT TIMES INTO THIS AFTERNOON AS A BROADER AREA OF
LOW PRESSURE MOVES FROM THE GREAT LAKES INTO EASTERN CANADA.
THIS PARENT LOW WILL KEEP UNSETTLED WEATHER IN THE FORECAST THROUGH
SATURDAY BEFORE MOVING OFFSHORE. HIGH PRESSURE THEN RETURNS
FOR SUNDAY.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...FOCUS OF HEAVY RAIN IS
SHIFTING EAST...AS RADAR SHOWS LAST SLUG OF MODERATE TO HEAVY RAIN
MOVING OVER NYC AND WESTERN LONG ISLAND ATTM. THIS AREA OF RAIN
SHOULD THEN MOVE OVER EASTERN LONG ISLAND AND SOUTHEAST CT LATER
AFTER 18Z OR SO. HAVE EXTENDED FLOOD WATCH UNTIL 4 PM TO ACCOUNT FOR
THIS LAST AREA OF PRECIP AND SUBSEQUENT RUNOFF. ELSEWHERE...HAVE KEPT
LIKELY POP AS ENOUGH MOISTURE/ELEVATED INSTABILITY WILL REMAIN
PRESENT TO POP UP SHOWERS AT ANY TIME.
&&

.SHORT TERM /6 PM THIS EVENING THROUGH SUNDAY/...
WARM FRONT WILL LIFT CLOSER TO THE AREA THIS EVENING AS SECONDARY
LOW LIFTS INTO THE GULF OF MAINE...MOVING THE FOCUS OF HEAVY
RAINFALL OFFSHORE. PRECIP WILL BECOME MORE SCATTERED THIS EVENING AND
THROUGH TONIGHT...AND WILL KEEP A SLIGHT CHANCE FOR THUNDERSTORMS
AFTER MIDNIGHT AS PARENT LOW MOVES INTO NORTHERN NEW YORK AND
NORTHERN NEW ENGLAND. MID LEVEL SHORTWAVE WILL SLIDE ACROSS THE AREA
SAT AFTERNOON...AND HAVE KEPT A CHANCE FOR SHOWERS/STORMS. COLD FRONT
PASSES THROUGH THE REGION SAT NIGHT...WINDS TURN W...AND THE AREA
BEGINS TO DRY OUT. ALTHOUGH THE PARENT LOW WILL SLOWLY LIFT
OFFSHORE...THERE MAY BE ENOUGH INSTABILITY TO TOUCH OFF SOME SHOWERS
ON SUN...BUT CHANCES LOOK LOW AND HAVE KEPT OUT OF THE FCST FOR NOW.

WARMEST TEMPS ON SAT WILL OCCUR OVER W PORTIONS OF THE CWA...WHERE
CLEARING WILL BEGIN EARLY ENOUGH TO PRODUCE ENOUGH SUNSHINE. HIGHS
WILL APPROACH 70 HERE...AND WILL BE IN THE 60S MOST ELSEWHERE. SUN
WILL FEATURE CLEARING SKIES WITH SLIGHTLY WARMER TEMPS.

&&

.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...HAVE UPDATED LONG TERM
EARLY TO CONCENTRATE ON NEAR/SHORT TERM THIS AFTERNOON. MEDIUM RANGE
MODEL GUIDANCE AND ADJUSTED HPC GUIDANCE WERE ALL CLOSE...SO HAVE USED
27/00Z GFS/MEX AS BASIS FOR FORECAST. COLD FRONT DROPS THROUGH THE
AREA ON MON WITH CHANCE POP FOR SOUTHERN CT/EASTERN LONG ISLAND AND
SLIGHT CHANCE ELSEWHERE AS ASSOCIATED MOISTURE LOOKS CONFINED TO MID
LEVELS. WEAK HIGH PRESSURE BUILDS IN LATER MON INTO MON NIGHT BEFORE
ANOTHER WAVE OF LOW PRESSURE SCOOTS TOWARD THE AREA FROM THE NORTHERN
PLAINS. ASSOCIATED FRONTAL SYSTEM APPROACHES BRINGING CHANCE POP INTO
TUE EVENING...AND NYC METRO MAY EVEN GET INTO THE WARM SECTOR TUE
AFTERNOON. 00Z GFS PREDICTS SFC- BASED LI OF 0 TO -2 IN WARM
SECTOR...WITH SHOWALTER INDICES FROM 0 TO -2 AREAWIDE...SO HAVE
FORECAST CHANCE OF THUNDER AS WELL. AFTER THIS WAVE MOVES
THROUGH...FAIR WX WITH NEAR NORMAL TEMPS WILL SETTLE IN FOR WED AND
THU WITH NW FLOW ALOFT AND CANADIAN HIGH PRESSURE BUILDING OVERHEAD.

&&

.AVIATION /16Z FRIDAY THROUGH TUESDAY/...MODERATE TO HEAVY SHOWERS
MOVING NORTHEASTWARD ALONG EASTERN SEABOARD. AREA TAF SITES HAVE
BEEN IN AND OUT OF THIS CONVECTION ALL MORNING WITH IFR VSBYS
GENERALLY...AND CEILINGS RUNNING LIFR/IFR TO OCCASIONALLY MVFR.
I EXPECT THIS TO CONTINUE THROUGH THE AFTERNOON AS WARM FRONT
REMAINS JUST SOUTH OF THE AREA...WITH LITTLE MOVEMENT EVIDENT.

MOST OF THE SHOWER ACTIVITY ASSOCIATED WITH OVERRUNNING PRECIP OVER
THIS LOW LEVEL BOUNDARIES. THE THREAT OF SHOWERS CONTINUE DUE TO
AXIS OF HIGH PRECIPITABLE WATER AND THETA E ADVECTION THROUGH THE
AFTERNOON...BEFORE SLIDING TO THE EAST.

BY THIS EVENING...FEEL THE WIDESPREAD COVERAGE OF SHOWERS WILL
SHRINK...AND I EXPECT MAINLY SCATTERED SHOWERS THEREAFTER. LOW
CLOUDS AND FOG HANG TOUGH ALL NIGHT AND INTO SATURDAY MORNING AS
COLD FRONT SLOWLY MOVES EAST. CEILINGS AND VSBYS IMPROVE TO VFR
AROUND 15Z SATURDAY MORNING AS TEMP/DEW POINT SPREADS INCREASE WITH
THE PASSAGE OF THE FRONT AND WESTERLY WINDS PICK UP.

THEREAFTER...POSSIBLE MVFR SAT NIGHT WITH UPPER TROUGH
PASSAGE...THEN IMPROVEMENT SUNDAY THROUGH EARLY TUESDAY AS RIDGE
EVENTUALLY BUILDS. A WEAK BACK DOOR FRONT ASSOCIATED WITH UPPER
SHORTWAVE SHOULD NOT AFFECT AREA EARLY MONDAY. ANOTHER SHORTWAVE
COULD BRING MORE RAIN LATER TUESDAY.

&&

.MARINE...
LOW PRESSURE ENTERING THE LOWER GREAT LAKES REGION WILL TRACK NE
ACROSS THE LAKES TODAY. THE SFC WARM FRONT WILL LIFT SLOWLY THROUGH
THE AREA WATERS THIS AFTERNOON. SOUTHERLY FLOW AROUND 15 KT ON THE
OCEAN WITH GUSTS TO 20 KT WILL LIKELY PRODUCE OCEAN SEAS MEETING
MARGINAL SCA CRITERIA. A TRAILING COLD FRONT WILL MOVE THROUGH FRI
NIGHT/SAT MORNING WITH A CYCLONIC WESTERLY FLOW TO PREVAIL THROUGH
EARLY NEXT WEEK. POST-FRONTAL WINDS AND SEAS LOOK TO REMAIN BELOW
SCA CRITERIA.

&&

.HYDROLOGY...OKX WSR-88D STORM TOTAL ESTIMATES OF 1.5-3 INCHES OVER A
NARROW BAND EXTENDING FROM NORTHEAST NJ ACROSS THE UPPER NYC BOROUGHS AND
SOUTHERN WESTCHESTER INTO SW CT LOOK CLOSE. COULD SEE UP TO ANOTHER
0.5 TO 1 INCH QPF ACROSS NYC...LONG ISLAND AND SE CT THIS AFTERNOON
WITH LAST SLUG OF MODERATE/HEAVY RAIN...AND FLOOD WATCH HAS BEEN
EXTENDED UNTIL 4 PM TO ACCOUNT FOR THIS AND SUBSEQUENT RUNOFF.
RIVER FLOOD WARNING ALREADY ISSUED FOR SMALL STREAMS IN UNION COUNTY
NJ...OTHER SMALL STREAMS SHOULD REMAIN WITHIN THEIR BANKS.

RIVER FLOOD WARNINGS REMAIN IN EFFECT FOR THE CONNECTICUT RIVER.
PLEASE REFER TO RIVER FLOOD PRODUCT ISSUED BY NWS TAUNTON MA
FOR DETAILS.

&&

.CLIMATE...CENTRAL PARK NOW UP TO 2.01 INCHES OF RAINFALL
TODAY...BREAKING THE DAILY RECORD SET IN 1889 AND PUSHING THE MONTHLY
TOTAL TO 13.02 INCHES...MAKING THIS MONTH THE 5TH WETTEST ON RECORD
AT THE PARK.

&&

.OKX WATCHES/WARNINGS/ADVISORIES...
CT...FLOOD WATCH UNTIL 4 PM EDT THIS AFTERNOON FOR CTZ005>012.
NY...FLOOD WATCH UNTIL 4 PM EDT THIS AFTERNOON FOR NYZ067>081.
NJ...FLOOD WATCH UNTIL 4 PM EDT THIS AFTERNOON FOR NJZ002>006-011.
MARINE...SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 2 PM EDT
     SATURDAY FOR ANZ350-353-355.

&&

UPDATE...GOODMAN
AVIATION...PW
HYDRO...FIG/GOODMAN

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE UPTON NY
1115 AM EDT FRI APR 27 2007

CTZ005>012-NJZ002>006-011-NYZ067>081-281200-
NORTHERN FAIRFIELD-NORTHERN NEW HAVEN-NORTHERN MIDDLESEX-
NORTHERN NEW LONDON-SOUTHERN FAIRFIELD-SOUTHERN NEW HAVEN-
SOUTHERN MIDDLESEX-SOUTHERN NEW LONDON-WESTERN PASSAIC-BERGEN-
EASTERN PASSAIC-ESSEX-HUDSON-UNION-ORANGE-PUTNAM-ROCKLAND-
NORTHERN WESTCHESTER-SOUTHERN WESTCHESTER-NEW YORK (MANHATTAN)-BRONX-
RICHMOND (STATEN ISLAND)-KINGS (BROOKLYN)-QUEENS-NASSAU-
NORTHWESTERN SUFFOLK-NORTHEASTERN SUFFOLK-SOUTHWESTERN SUFFOLK-
SOUTHEASTERN SUFFOLK-
1115 AM EDT FRI APR 27 2007

...FLOOD WATCH IN EFFECT UNTIL 4 PM EDT THIS AFTERNOON...

THIS HAZARDOUS WEATHER OUTLOOK IS FOR SOUTHERN
CONNECTICUT...NORTHEAST NEW JERSEY AND SOUTHEAST NEW YORK.

.DAY ONE...THIS AFTERNOON AND TONIGHT
OCCASIONAL HEAVY RAIN EXPECTED THIS AFTERNOON WILL CAUSE WIDESPREAD
URBAN FLOODING...ALONG WITH RIVER AND SMALL STREAM FLOODING.

PLEASE LISTEN TO NOAA WEATHER RADIO OR GO TO WEATHER.GOV ON THE
INTERNET FOR MORE INFORMATION ABOUT THE FOLLOWING HAZARDS.

   FLOOD WATCH

.DAYS TWO THROUGH SEVEN...SATURDAY THROUGH THURSDAY

NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME.

.SPOTTER INFORMATION STATEMENT...

WEATHER SPOTTERS ARE ENCOURAGED TO REPORT SIGNIFICANT WEATHER
CONDITIONS ACCORDING TO STANDARD OPERATING PROCEDURES.

ANZ330-335-338-340-345-350-353-355-281200-
LONG ISLAND SOUND EAST OF NEW HAVEN CT/PORT JEFFERSON NY-
LONG ISLAND SOUND WEST OF NEW HAVEN CT/PORT JEFFERSON NY-
NEW YORK HARBOR-PECONIC AND GARDINERS BAYS-
SOUTH SHORE BAYS FROM JONES INLET THROUGH SHINNECOCK BAY-
MORICHES INLET NY TO MONTAUK POINT NY OUT 20 NM-
FIRE ISLAND INLET NY TO MORICHES INLET NY OUT 20 NM-
SANDY HOOK NJ TO FIRE ISLAND INLET NY OUT 20 NM-
1115 AM EDT FRI APR 27 2007

THIS HAZARDOUS WEATHER OUTLOOK IS FOR ATLANTIC COASTAL WATERS.

.DAY ONE...THIS AFTERNOON AND TONIGHT

NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME.

.DAYS TWO THROUGH SEVEN...SATURDAY THROUGH THURSDAY

NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME.

.SPOTTER INFORMATION STATEMENT...

WEATHER SPOTTERS ARE ENCOURAGED TO REPORT SIGNIFICANT WEATHER
CONDITIONS ACCORDING TO STANDARD OPERATING PROCEDURES.