341
FXUS61 KOKX 071148
AFDOKX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE UPTON NY
748 AM EDT SUN SEP 7 2008
SYNOPSIS
WEAK HIGH PRESSURE BUILDS IN FROM THE WEST THROUGH TONIGHT...THEN
SLIDES OFF THE MID ATLANTIC COAST ON MONDAY AND MONDAY NIGHT. A
COLD FRONT WILL APPROACH FROM THE WEST ON TUESDAY...THEN CROSS THE
TRI-STATE TUESDAY NIGHT. HIGH PRESSURE THEN RIDGES IN FROM THE
GREAT LAKES WEDNESDAY AND WEDNESDAY NIGHT...THEN MOVES OFF THE NEW
ENGLAND COAST ON THURSDAY. THIS HIGH WILL THEN DOMINATE OUR
WEATHER THROUGH FRIDAY. A COLD FRONT WILL SLOWLY APPROACH FROM THE
WEST FRIDAY NIGHT AND SATURDAY.
NEAR TERM /UNTIL 6 PM THIS EVENING/
WINDS SHOULD QUICKLY DIMINISH THIS MORNING (LAST LINGERING IMPACT
OF HANNA)...OTHERWISE A TYPICAL EARLY FALL DAY (METEOROLOGICAL
FALL BEGAN SEPTEMBER 1ST). 20 KT OF WNW DOWNSLOPE FLOW WILL MINIMIZE
CLOUD COVER AND COUPLED WITH 850 TEMPERATURES OF 13-15C WILL
PROMOTE ABOVE NORMAL TEMPERATURES TODAY. USED A BLEND OF
MAV/FWC/MET TEMPERATURES...TEMPERING MAV NUMBERS WHICH HAVE RUN A
BIT ON THE HIGH SIDE IN SIMILAR REGIMES DURING THE SUMMER.
SHORT TERM /6 PM THIS EVENING THROUGH TUESDAY NIGHT/
WESTWARD EXTENSION OF BERMUDA HIGH BUILDS IN THROUGH THE MID
LEVELS...WITH RISING HEIGHTS AND ZONAL FLOW KEEPING THINGS DRY
INTO TUESDAY MORNING. SLIGHTLY COOLER 850 TEMPERATURES WILL YIELD
HIGHS A BIT COOLER THAN TODAY ON MONDAY. RELATIVELY CLEAR SKY
CONDITIONS AND LIGHT WINDS SHOULD PROMOTE DECENT RADIATIONAL
COOLING TONIGHT...WITH LOWS BELOW NORMAL (LOWER 50S NORMAL COOL
SPOTS MID 50S TO AROUND 60 ELSEWHERE). SOUTHERLY RETURN FLOW
MONDAY NIGHT SHOULD RESULT IN LOWS A FEW DEGREES WARMER MONDAY
NIGHT THAN TONIGHT. FOLLOWED A MET/FWC BLEND AT NIGHT (MAV TOO
WARM) AND A MET/FWC/MAV BLEND DURING THE DAY (TEMPERING MAV
NUMBERS A TAD BUT REFLECTING IMPACT OF DOWNSLOPE FLOW).
AN APPROACHING STRONG COLD FRONT SHOULD BRING A CHANCE OF SHOWERS
AND THUNDERSTORMS BY TUESDAY AFTERNOON...WITH THEM BECOMING MORE
WIDESPREAD TUESDAY NIGHT AS THE FRONT CROSSES THE TRI-STATE. WITH
1000-1500 J/KG OF CAPE BY LATE AFTERNOON/EARLY EVENING...THETA-E
RIDGE BUILDING OVER AREA AND DECENT SHEAR...HAVE THE POTENTIAL FOR
SOME STRONG TO POSSIBLY SEVERE STORMS LATE TUESDAY AFTERNOON AND
EVENING.
LONG TERM /WEDNESDAY THROUGH SATURDAY/
LONGER RANGE MODELS IN FAIRLY GOOD AGREEMENT THROUGH THURSDAY
NIGHT...THEN ECMWF IS MUCH FASTER IN BRINGING A COLD FRONT THROUGH
THAN THE GFS TO CLOSE THE WEEK (DUE TO DIFFERENCES IN HANDLING
HIGH OFFSHORE). DUE TO THESE DIFFERENCES AND NO CLEAR CUT REASON
TO FAVOR ONE OVER THE OTHER...MADE LITTLE CHANGES IN THE
FRIDAY/SATURDAY TIME FRAME (WHICH ALREADY WAS LEANING TOWARDS
SLOWER FRONTAL PASSAGE.
WILL BE NOTICEABLY COOLER BEHIND COLD FRONT WEDNESDAY/THURSDAY WITH
HIGHS IN THE LOWER TO MID 70S. DID LOWER LOWS WEDNESDAY NIGHT (NOW
HAVE UPPER 40S IN NORMAL COLDER LOCATIONS) AND THURSDAY
NIGHT...HOWEVER BELIEVE THAT WILL END UP BEING LOWERED FURTHER AS
GUIDANCE OFTEN UNDERESTIMATES AMOUNT OF COLD AIR BEHIND THESE
EARLY SEASON FRONTS (TYPICALLY UNDER DOES STRENGTH OF HIGH BUILDING
IN FROM SOUTH CENTRAL CANADA)...THEN WITH HIGH OFFSHORE AND SW
RETURN FLOW SETTING UP SHOULD SEE MODERATING TEMPERATURES
FRIDAY AND SATURDAY. WITH DIFFERENCES IN FRONTAL TIMING DO HAVE
CHANCE POPS IN FRIDAY-SATURDAY (COULD END UP BEING MORE DIURNAL
FRIDAY AFTERNOON/EVENING AND DRY IN THE MORNING AND LATE AT NIGHT
VICE CURRENT BLANKET CHANCE POPS CURRENTLY IN FORECAST).
AVIATION /12Z SUNDAY THROUGH THURSDAY/
VFR CONDITION IN THE WAKE OF T.S. HANNA.
GUSTY NW WINDS HAVE RELAXED AS PRESSURE RISES DECREASE. THERE MAY
BE A FEW GUSTS THROUGH THE MORNING THAT RESULT IN A TAIL WIND AT
KEWR. NO OTHER AVIATION IMPACTS EXPECTED TODAY.
OUTLOOK FOR 06Z MONDAY THROUGH THURSDAY...
HIGH PRESSURE AND VFR MONDAY. SHOWERS/TSTMS COULD PRODUCE SUB VFR
CONDITIONS TUE AFTERNOON INTO TUE NIGHT AHEAD OF AN APPROACHING
COLD FRONT. HIGH PRESSURE AND VFR CONDITIONS RETURN WED AND THU.
MARINE
LARGE SEA/SWELL COMBINATION STILL EXISTS IN THE WAKE OF HANNA ACROSS
OCEAN WATERS. THIS WILL PRODUCE POUNDING HIGH SURF AND DANGEROUS
RIP CURRENTS TODAY...WITH THE HIGH SURF DIMINISHING TODAY...BUT
STRONG RIP CURRENTS ARE EXPECTED TO CONTINUE INTO TUESDAY. REFER
TO THE LATEST COASTAL FLOOD STATEMENT FOR DETAILS.
THE PRESSURE FIELDS OVER THE AREA SUPPORTS A
CONTINUING DECREASE IN WINDS SPEEDS. HOWEVER...SEAS WILL BE A BE
SLOWER TO RESPOND...MAINLY DUE TO THE LONGER PERIOD SWELL IN PLACE.
A SMALL CRAFT ADVISORY CURRENTLY IN EFFECT WILL EXPIRE FOR LI
SOUND/NY HARBOR/AND ALL BAYS AT 11AM. OCEAN WATERS WILL SEE SMALL
CRAFT SEAS THROUGH TONIGHT.
HIGH PRESSURE BUILDING IN WILL ALLOW CONDITIONS TO CONTINUE TO
DIMINISH INTO MONDAY.
WINDS BACK TO SOUTHERLY AND PICK UP AGAIN TUESDAY AHEAD OF A POTENT
COLD FRONT. SCA WINDS MAY BE REACHED SOUTH OF LI AHEAD OF THE
FRONT...AND GUSTY NW WINDS AND HIGHER SEAS MAY NECESSITATE A SCA ON
WEDNESDAY MORNING.
LONG PERIOD SWELLS FROM HURRICANE IKE MAY IMPACT THE LOCAL WATERS
THROUGH MUCH OF NEXT WEEK.
HYDROLOGY
RIVER FLOODING ONGOING THIS MORNING. IN NEW JERSEY...THE SADDLE
BROOK NEAR LODI REMAINS ABOVE MODERATE FLOOD STAGE...BTU APPEAR TO
BE REACHING ITS CREST AT THIS TIME NEAR 7.8 FEET. A RIVER FLOOD
WARNING REMAINS IN EFFECT THROUGH THIS MORNING UNTIL THE FLOOD
STAGE OF 6.0 FEET IS REACHED.
SMALLER STREAMS IN NJ HAVE FALLEN BELOW FLOOD STAGE.
THE POMPERAUG RIVER IN NEW HAVEN COUNTY CT HAS GONE ABOVE FLOOD
STAGE (9.0 FEET)...BUT ALSO APPEARS TO BE CRESTING. NO OTHER NEW
FLOODING IS EXPECTED WITH RAINFALL HAVING ENDED ACROSS THE
HYDROLOGIC SERVICE AREA...AND RIVER LEVELS WILL CONTINUE TO RECEDE
WITH DRY WEATHER SUNDAY AND MONDAY.
THE NEXT CHANCE FOR RAINFALL IS TUESDAY AFTERNOON AND NIGHT...WITH
ABOUT 0.5 INCHES EXPECTED BASIN WIDE. LOCALLY HIGHER AMOUNTS ARE
POSSIBLE IN THUNDERSTORMS.
OKX WATCHES/WARNINGS/ADVISORIES
CT...NONE.
NY...HIGH SURF ADVISORY UNTIL 6 PM EDT THIS AFTERNOON FOR
NYZ075>077-080-081.
NJ...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 11 AM EDT THIS MORNING FOR ANZ330-
335-338-340-345-355.
SMALL CRAFT ADVISORY UNTIL 1 AM EDT MONDAY FOR ANZ350-353.
SYNOPSIS...PFM
NEAR TERM...PFM
SHORT TERM...PFM
LONG TERM...MAS/PFM
AVIATION...BS
MARINE...BS
HYDROLOGY...BS/PFM
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