-- Discussion containing changed information from previous version are highlighted. --
000
FXUS61 KOKX 240244
AFDOKX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NEW YORK NY
1044 PM EDT THU MAY 23 2013

.SYNOPSIS...
A COLD FRONT MOVES INTO THE AREA OVERNIGHT...A WAVE OF LOW
PRESSURE THEN FORMS ALONG IT NEAR THE AREA FRIDAY...AND SLOWLY
TRACKS TO THE GULF OF MAINE BY SUNDAY MORNING. HIS LOW SLOWLY THEN
LIFTS INTO THE CANADIAN MARITIMES THROUGH MONDAY. HIGH PRESSURE
THEN BUILDS INTO THE SOUTH THROUGH WEDNESDAY NIGHT. A WARM FRONT
WILL APPROACH ON THURSDAY.

&&

.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
MAIN AREA OF FOCUS CONTINUES TO BE ACROSS NE NJ AND THE LOWER
HUDSON VALLEY WHERE HEAVY RAIN PRODUCING SHOWERS AND THUNDERSTORMS
CONTINUE TO MOVE ACROSS THE AREA. WHILE THERE IS LESS ORGANIZATION
THAN THERE WAS EARLIER IN THE DAY...ANY ADDITIONAL HEAVY RAINFALL
CONTINUES TO EXACERBATE THE ONGOING FLOODING. NUMEROUS STREAMS
AND RIVERS ARE OUT OF THEIR BANKS...IN PARTICULAR...ACROSS BERGEN
COUNTY NJ. MOST OF THE RIVER GAUGES ACROSS THIS AREA SHOW MAINLY
MINOR FLOODING...BUT THERE HAVE BEEN REPORTS OF SOME PROPERTIES
TAKING ON WATER WITH ABOUT A FOOT OF RUNNING WATER.

AHEAD OF THE COLD FRONT...ACROSS EASTERN PA...THEIR ARE WIDESPREAD
SHOWERS AND EMBEDDED THUNDERSTORMS. MODELS CONTINUE TO INDICATE A
GRADUAL DISSIPATION OF THIS AREA...WITH SOME ENHANCEMENT OF THE
ACTIVITY ACROSS EASTERN LI AND SE CT FROM NOW UNTIL EARLY MORNING.
THE FRONT THEN ARRIVES AROUND DAYBREAK ACROSS THE WESTERN ZONES
WITH THE POTENTIAL FOR ADDITIONAL CONVECTION.

BASED ON THE SEVERAL INCHES OF RAINFALL THAT HAS FALLEN ACROSS NE
NJ AND THE LOWER HUDSON VALLEY...LONGER TERM FLOODING MAY BECOME
AN ISSUE AND AREAL FLOOD WARNING MAY NEED TO REPLACE THE ONGOING
FLASH FLOOD WARNINGS. THIS WILL DEPEND IN HOW WELL THE CONVECTION
UPSTREAM REMAINS IN TACT.

THE SEVERE WEATHER THREAT IS DIMINISHING WITH A WEAKENING WIND
SHEAR PROFILE AND INCREASING LOW-LEVEL STABILITY.

FOR LOWS TONIGHT USED A BLEND OF MAV/MET GUIDANCE WITH NAM
2-METER TEMPERATURES WITH VALUES AROUND 10 DEGREES ABOVE NORMAL.

&&

.SHORT TERM /6 AM FRIDAY MORNING THROUGH FRIDAY NIGHT/...
HEAVY RAINFALL THREAT COMES TO AN END FRIDAY MORNING WITH
AFOREMENTIONED 250 HPA JET AXIS SLIDING TO OUR EAST ALONG WITH THE
DEVELOPMENT OF A WAVE OF LOW PRESSURE NEAR THE TRI-STATE AND
TRACKING INTO EASTERN PORTIONS OF THE AREA IN THE AFTERNOON.

CONTINUED MOIST S FLOW INT HE MID LEVELS ALONG WITH LOWS FROM 700
HPA DOWN TO THE SURFACE MOVING OVER THE AREA WILL BRING MAINLY
SHOWERY PRECIPITATION TO THE AREA FROM FRIDAY AFTERNOON INTO
FRIDAY EVENING...QUITE LIKELY TRANSITIONING TO STRATIFORM
PRECIPITATION AFTER MIDNIGHT WITH THE SURFACE LOW SLIDING TO THE
EAST...AND ISENTROPIC LIFT - ALTHOUGH WEAK - TAKING OVER.

FOR HIGHS FRIDAY USED A BLEND OF NAM 2-METER TEMPERATURES WITH A
MIX DOWN FROM 925 HPA PER BUFKIT SOUNDINGS AND MAV AND MET
GUIDANCE. EXPECT HIGHS TO BE NEAR TO SLIGHTLY BELOW NORMAL.

FOR TEMPERATURES FRIDAY NIGHT USED A BLEND OF NAM 2-METER
TEMPERATURES WITH MAV AND MET GUIDANCE WITH LOWS NEAR TO SLIGHTLY
BELOW NORMAL.

&&

.LONG TERM /SATURDAY THROUGH THURSDAY/...
GFS/NAM/ECMWF ALL REASONABLY CLOSE IN THEIR INTENSITY AND MOVEMENT
OF THE CLOSED LOW AND ASSOCIATED LOW PRESSURE MOVING SLOWLY NE THIS
WEEKEND. HAVE SHIFTED FOCUS OF CATEGORICAL POP INITIALLY ON SAT TO
AREAS FROM NYC WEST WHERE HEAVIER COMMA HEAD PRECIP WILL BE
FALLING...THEN E-WARD ACROSS THE REST OF THE AREA INTO THE AFTERNOON
AND EVENING. N-NW WINDS ON THE BACK SIDE OF THE LOW SHOULD BECOME
RATHER BRISK BY SAT AFTERNOON...FALLING JUST SHY OF ADVISORY
CRITERIA AT 15-25 MPH WITH WITH GUSTS 40-45 MPH INTO EARLY SAT
EVENING. CANNOT RULE OUT A TSTM OVER ERN CT/LONG ISLAND VIA SOME
ELEVATED DESTABILIZATION AS DRY SLOT PUNCHES IN FROM THE SW. TEMPS
WILL BE RATHER COOL FOR LATE MAY...WITH HIGHS ONLY 55-60 AND
DROPPING INTO THE 40S SAT NIGHT.

STEADY RAIN SHOULD SHIFT EAST AND TAPER OFF IN INTENSITY SAT NIGHT
AS THE LOW PULLS E OF NEW ENGLAND...BECOMING MORE SHOWERY/ISOLD IN
NATURE ON SUNDAY VIA CYCLONIC LOW LEVEL FLOW AND PASSAGE OF
TRANSIENT MID LEVEL VORTICITY MAXES PINWHEELING AROUND THE UPPER LOW.
STILL COOL AND BREEZY ON SAT WITH HIGHS ONLY UPPER 50S/LOWER
60S...AND GUSTS 25-30 MPH.

DRY WX AND A GRADUAL WARM-UP TO NEAR SEASONABLE LEVELS IS THEN
FORECAST MON-WED AS HIGH PRESSURE MOVES ACROSS. TEMPS ON THU SHOULD
RETURN TO MORE SUMMER-LIKE LEVELS WITH THE APPROACH OF A WARM
FRONT...WHICH COULD BRING AFTERNOON SHOWERS AND POSSIBLE TSTMS
MAINLY TO AREAS WEST OF NYC.

&&

.AVIATION /03Z FRIDAY THROUGH TUESDAY/...
-- Changed Discussion --
LOW PRESSURE AND A COLD FRONTAL BOUNDARY WILL MOVE SLOWLY THROUGH
THE AREA OVERNIGHT INTO FRIDAY...PASSING EAST OF LONG ISLAND LATE IN
THE FORECAST PERIOD. NUMEROUS SHOWERS WILL CONTINUE THROUGH THE
PERIOD. AN ISOLATED THUNDERSTORM WILL ALSO BE POSSIBLE UNTIL AROUND
05Z...MAINLY WEST OF NEW YORK CITY.

SOUTHERLY WIND WILL SHIFT TO THE SOUTHWEST AND WEST AS THE FRONT
PASSES THROUGH AFTER 10Z...AND THEN BECOME NORTHERLY AS THE LOW
MOVES FARTHER TO THE EAST DURING FRIDAY.

IFR TO LIFR CEILINGS WILL BE WIDESPREAD WITH VISIBILITIES MVFR TO
IFR IN SHOWERS AND FOG. CONDITIONS BEGIN TO IMPROVE SLOWLY FRIDAY
MORNING BEHIND FRONT. TIMING IS A LITTLE UNCERTAIN AT THIS TIME.

.OUTLOOK FOR 00Z SATURDAY THROUGH TUESDAY...
.FRIDAY NIGHT...NUMEROUS SHOWERS. MVFR TO IFR IN SHOWERS...FOG AND
STRATUS.
.SATURDAY...NUMEROUS SHOWERS WITH MVFR TO IFR. N WIND 25-30G35KT.
.SUNDAY...SCATTERED SHOWERS...IMPROVING CONDITIONS TO VFR. NW WIND
20-25KT. POTENTIAL FOR GUSTS UP TO 40KT.
.MONDAY THROUGH TUESDAY...VFR.
-- End Changed Discussion --

&&

.MARINE...
SCA REMAINS UP FOR THE OCEAN WATERS THROUGH AT LEAST FRIDAY NIGHT
AS A LINGERING SWELL LIKELY KEEPS SEAS UP OVER 5 FT OVER A GOOD
PORTION OF THE OCEAN WATERS. GUSTS TO 25 KTS WILL BE POSSIBLE AS
WELL DURING PARTS OF THIS PERIOD ON THE OCEAN WATERS. NON-OCEAN
WATERS THROUGH FRIDAY SHOULD SEE GUSTS PEAK AT AROUND 20 KT...BUT
A FEW GUSTS TO 25 KT CANNOT BE COMPLETELY RULED OUT.

GUSTS IN STRENGTHENING N-NW FLOW ON THE BACK SIDE OF THE LOW AS IT
MOVES E OF NEW ENGLAND COULD REACH GALE FORCE SAT AFTERNOON/EVENING.
SCA CONDITIONS LIKELY TO CONTINUE ON ALL WATERS INTO SUNDAY
AFTERNOON...THEN GRADUALLY TAPER OFF ON THE OCEAN AND THEN ERN
SOUND/BAYS SUNDAY NIGHT. QUIET CONDITIONS EXPECTED MON-TUE VIA
BUILDING HIGH PRESSURE.

&&

.HYDROLOGY...
AREAL FLOOD WARNINGS MAY REPLACE THE FLASH FLOOD WARNINGS ACROSS NE
NJ AND THE LOWER HUDSON VALLEY OVER THE NEXT SEVERAL HOURS
DEPENDING ON HOW WELL THE CONVECTION UPSTREAM REMAIN IN TACT.

THERE IS THE POTENTIAL FOR ANOTHER 1/4 TO 1/2 INCH OF RAINFALL
WITH LOCALLY HIGHER AMOUNTS THROUGH MORNING. PRECIPITABLE WATER
VALUES OF AROUND 1.75 INCHES TONIGHT WILL ALLOW FOR RAINFALL RATES
TO APPROACH 2 INCHES AN HOUR IN ISOLATED STRONG CONVECTION. AS A
RESULT EXPECT ADDITIONAL LOCALIZED FLASH FLOODING FROM TONIGHT
INTO FRIDAY MORNING.

AN ADDITIONAL 1/2-3/4 OF INCH OF RAINFALL IS EXPECTED FROM FRIDAY
AFTERNOON THROUGH FRIDAY NIGHT - WITH LOCALLY HIGHER AMOUNTS
POSSIBLE. PRECIPITABLE WATERS DO DECREASE TO UNDER 1 INCH BY LATE
FRIDAY NIGHT. AS A RESULT...THE RISK OF MINOR URBAN FLOODING IN
THIS TIME FRAME WILL LIKELY BE RESTRICTED TO FRIDAY
AFTERNOON/EVENING...IF ANY OCCURS.

BASIN AVG QPF OF 1/2 TO 3/4 INCH EXPECTED SAT INTO SAT NIGHT...THEN
ONLY MINIMAL QPF IN LINGERING SHOWERS ON SUNDAY.

FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING OBSERVED
AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE VISIT THE
ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON OUR WEBSITE.

&&

.OKX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
NJ...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 6 AM EDT SATURDAY FOR ANZ350-353-
     355.

&&

$$
SYNOPSIS...GOODMAN/MALOIT/NV
NEAR TERM...MALOIT/DW
SHORT TERM...MALOIT
LONG TERM...GOODMAN
AVIATION...MET
MARINE...GOODMAN/MALOIT
HYDROLOGY...GOODMAN/MALOIT/NV