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-- Discussion containing changed information from previous version are highlighted. --
000
FXUS61 KOKX 191853
AFDOKX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NEW YORK NY
253 PM EDT SUN MAY 19 2013

.SYNOPSIS...
A STATIONARY FRONT WILL REMAIN TO THE S THROUGH TONIGHT...THEN
LIFT TO THE NORTH MONDAY INTO MONDAY NIGHT. A COLD FRONT WILL DROP
THROUGH ON TUESDAY...THEN REMAIN NEARBY BEFORE LIFTING BACK NORTH
AS A WARM FRONT ON THURSDAY. A COLD FRONTAL PASSAGE WILL OCCUR
LATE IN THE WEEK OR EARLY NEXT WEEKEND.

&&

.NEAR TERM /THROUGH TONIGHT/...
-- Changed Discussion --
WEAK WAA STILL CAUSING LIGHT RAIN TO CONTINUE ACROSS MOST OF THE
AREA THIS AFTERNOON. UPDATED POP TO LIKELY/CAT FOR MOST OF THE AREA
PER RADAR TREND. THIS GENERAL SCENARIO SHOULD LAST INTO THIS
EVENING AS A DIFFUSE WARM FRONT TO THE SOUTH APPROACHES...THEN POP
SHOULD TAPER OFF AFTER MIDNIGHT FROM WEST TO EAST AS BEST
ISENTROPIC LIFT MOVES TO THE NE. TEMPS SHOULD REMAIN NEARLY
STEADY TONIGHT IN THE MID AND UPPER 50S...AND COULD SLOWLY
INCREASE TOWARD DAYBREAK. AS HIGHER DEWPOINT AIR ADVECTS
IN...POTENTIAL FOR FOG WILL ALSO INCREASE ESPECIALLY LATE TONIGHT.
-- End Changed Discussion --

&&

.SHORT TERM /MONDAY THROUGH MONDAY NIGHT/...
-- Changed Discussion --
THE REGION WILL BE WARM SECTORED ON MONDAY. EXPECT AT LEAST
PARTIAL CLEARING TO OCCUR...WHICH WILL DETERMINE AMT OF DAYTIME
HEATING/INSTABILITY. FORCING RELATIVELY WEAK...SO EXPECT ONLY
ISOLD TO SCT SHOWERS IN THE AFTERNOON. WITH WEAK STEERING FLOW
AND PW NEAR 1.5 INCHES...ANY SHOWER/TSTM COULD DUMP LOCALLY HEAVY
RAIN. HIGH-RES MESOSCALE MODELS SUCH AS SPC WRF AND HIGH-RES ARW
AGREE ON THIS SCENARIO.

EXPECT DAYTIME HIGHS TO REACH THE LOWER 80S FROM NYC NORTH/WEST
AND INTO THE 70S ELSEWHERE. TEMPS COULD BE A COUPLE DEG HIGHER IF
MORE AFTERNOON SUNSHINE TAKES PLACE THAN FCST.

ANY CONVECTION SHOULD WANE MON EVENING. IT NOW APPEARS THAT A BACK
DOOR COLD FRONT APPROACHING FROM NEW ENGLAND SHOULD HOLD OFF UNTIL
TUE MORNING...SO WITH AREA REMAINING IN THE WARM SECTOR WOULD
EXPECT REDEVELOPMENT OF FOG...ESPECIALLY ALONG THE COAST.
-- End Changed Discussion --

&&

.LONG TERM /TUESDAY THROUGH SATURDAY/...
PREDICTABILITY ISSUES DURING THIS TIME PERIOD HAVE TO DO WITH THE
INTERACTION OF EASTERN CANADIAN TROUGHING AND CENTRAL US TROUGHING
THIS WEEK. THE INTERACTION OF THESE TWO ENERGIES WILL DETERMINE THE
MAGNITUDE OF EAST COAST RIDGING FOR THE MIDWEEK. MODELS SIGNALING A
RETURN TO EAST COAST TROUGHING FOR THE WEEKEND AS EAST COAST RIDGING
BUILDS OFFSHORE INTO THE WESTERN ATLANTIC.

SHOWERS AND THUNDERSTORMS COULD CONTINUE TUESDAY NIGHT...WITH
INDICATIONS OF A WAVE OF LOW PRESSURE TRACKING EAST ALONG THE
SAGGING FRONTAL BOUNDARY. MOISTURE POOLING AND STEERING FLOW
PARALLEL TO THE SURFACE BOUNDARY WOULD PRESENT A FLASH FLOOD
THREAT IF THIS PATTERN MATERIALIZED.

THEN FOR THE MID-LATE WEEK PERIOD THE INTERACTION OF THE EARLIER
MENTIONED UPPER FEATURES WILL BE CRITICAL TO THE LOCATION OF THE
FRONTAL BOUNDARY. LATEST GUIDANCE HAS STRONGLY CONVERGED ON THE
BACKDOOR COLD FRONT PUSHING SOUTH THROUGH THE REGION TUESDAY
NIGHT...AND THEN BACK NORTH AS A WARM FRONT ON THURSDAY. IF THE
FRONT DOES PASS SOUTH...ONSHORE FLOW AND CLOUDS WOULD LIKELY DROP
MAX TEMPS TO SEASONABLE OR SLIGHTLY BELOW SEASONABLE LEVELS FOR
WED...SEVERAL DEGREES COOLER THEN FORECAST.

REGARDLESS OF WHERE THE WARM FRONT ENDS UP...IF THIS BOUNDARY
REMAINS CLOSE TO THE REGION...SHORTWAVES AT THE SOUTHERN EDGE OF THE
WESTERLIES MAY ALLOW FOR CONVECTIVE COMPLEXES TO FORM AND TRACK WEST
TO EAST ALONG THIS BOUNDARY THROUGH THE MID-LATE WEEK PERIOD. ANY
MCS WOULD BRING THE THREAT FOR HEAVY RAIN AND SEVERE WEATHER.

BY THE END OF THE WEEK...MODELS ARE SIGNALING VARYING DEGREES OF
PHASING OF THE MIDWEST UPPER TROUGH AND EASTERN CANADIAN UPPER
TROUGH. THIS WILL HAVE A COLD FRONT PASSING THROUGH THE REGION
SOMETIME FRI INTO SAT...WITH SHOWER AND THUNDERSTORM ACTIVITY
FINALLY EXITING IN IT WAKE. DEGREE OF PHASING OF UPPER ENERGIES WILL
DETERMINE TIMING AND ACTIVITY ALONG THE FRONT.

&&

.AVIATION /19Z SUNDAY THROUGH FRIDAY/...
A FRONTAL BOUNDARY APPROACHES FROM THE SOUTH TODAY AND TONIGHT.

SUB VFR THROUGH MUCH OF THE FORECAST. CONDITIONS HAVE FALLEN TO
MVFR-IFR THIS AFTERNOON AND ARE EXPECTED TO REMAIN DOWN THROUGH
TONIGHT AS A WARM FRONT APPROACHES FROM THE SOUTH. LITTLE TO NO
IMPROVEMENT IS EXPECTED...ESPECIALLY ALONG THE COASTAL
TERMINALS...AND IF ANY IMPROVEMENT DOES OCCUR...IT WONT LAST VERY
LONG.

CONDITIONS TONIGHT CONTINUE TO FALL TO IFR OR LESS AT ALL THE AREA
TERMINALS. THE LOW STRATUS WILL BE OVER THE REGION LOWERING CIGS TO
ANYWHERE FROM 200-1000 FT. QUESTION IS HOW MUCH FOG DEVELOPS. WILL
LIMIT VSBY RESTRICTIONS TO JUST 2 MILES FOR NOW...HOWEVER VSBYS
COULD FALL TO LESS THAN A MILE IN SPOTS.

WINDS WILL REMAIN FROM THE SOUTHEAST TODAY...THEN BECOME LIGHT AND
VARIABLE OVERNIGHT. TOMORROW...WINDS BECOME SOUTH OR SOUTHWEST AND
REMAIN LESS THAN 10 KT.

.OUTLOOK FOR 12Z MONDAY THROUGH THURSDAY...

.MONDAY...IMPROVEMENT TO VFR BY LATE MORNING OR EARLY AFTERNOON.
SCATTERED SHOWERS...AND ISOLATED THUNDERSTORMS WITH BRIEF MVFR
CONDITIONS POSSIBLE IN THE AFTERNOON.

.MONDAY NIGHT...MVFR OR LOWER CONDITIONS LIKELY WITH LOW CLOUDS AND
FOG.

.TUESDAY-THURSDAY...CHANCE OF MVFR OF LOWER CONDITIONS IN SHOWERS AND
THUNDERSTORMS.

.FRIDAY...CHANCE OF MVFR IN ANY LEFT OVER SHOWERS AND THUNDERSTORMS
EARLY.

&&

.MARINE...
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AS HIGH PRESSURE PASSES TO THE EAST AND A WARM FRONT APPROACHES
FROM THE SOUTH...SE-S WINDS SHOULD INCREASE TO 15 TO 20
KT...MAINLY ACROSS THE OCEAN WATERS. OCEAN SEAS STILL 2-4
FT...SHOULD REACH SCA CRITERIA OF 5 FT THIS EVENING...SO PUSHED
START TIME OF OCEAN SCA FORWARD A LITTLE MORE TO 6 PM. SCA LEVEL
OCEAN SEAS SHOULD LAST INTO MON AFTERNOON..POSSIBLY MON EVENING
OUT EAST.

WINDS SHOULD TURN TOWARD THE SOUTHWEST THROUGH MONDAY. A FRONTAL
BOUNDARY APPROACHES FROM THE NORTH BY TUESDAY...AND WINDS LIGHTEN
AND COULD SHIFT AROUND TO THE NORTHEAST OR EAST DEPENDING ON HOW
FAR SOUTH THE FRONT MOVES.

EVENTUALLY THIS FRONT IS EXPECTED TO MOVE BACK TO THE NORTH
RESULTING IN A WIND SHIFT TO THE SOUTH ONCE AGAIN BY MID WEEK.
-- End Changed Discussion --

&&

.HYDROLOGY...
-- Changed Discussion --
UP TO 1/2 TENTHS OF AN INCH QPF EXPECTED THROUGH TONIGHT. SCT
SHOWERS/TSTMS MON THROUGH FRI ARE CAPABLE OF PRODUCING LOCALLY
HEAVY RAINFALL...WITH AN ATTENDANT LOW FLASH FLOOD THREAT.
-- End Changed Discussion --

&&

.OKX WATCHES/WARNINGS/ADVISORIES...
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CT...NONE.
NY...NONE.
NJ...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 6 PM THIS EVENING TO 9 AM EDT MONDAY
     FOR ANZ355.
     SMALL CRAFT ADVISORY FROM 6 PM THIS EVENING TO 6 PM EDT MONDAY
     FOR ANZ350-353.
-- End Changed Discussion --

&&

$$