000
FXUS61 KOKX 182357
AFDOKX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NEW YORK NY
757 PM EDT SAT MAY 18 2013

.SYNOPSIS...
HIGH PRESSURE WILL CONTINUE TO SLIDE EAST OF THE AREA TONIGHT. 
A WARM FRONT WILL APPROACH FROM THE MID ATLANTIC STATES SUNDAY INTO 
SUNDAY NIGHT. A WARM FRONT WILL PASS TO THE NORTH ON MONDAY. THE
FRONT THEN REMAINS IN CLOSE PROXIMITY TO THE AREA THROUGH THE
WEEK...QUITE POSSIBLY PASSING SOUTH AS A COLD FRONT LATE TUESDAY
AND THEN BACK NORTH AS A WARM FRONT ON THURSDAY. A COLD FRONTAL
PASSAGE OCCURS LATE IN THE WEEK OR EARLY WEEKEND.

&&

.NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
THE BULK OF JET STREAK INDUCED LIGHT RAIN SHOWER AND SPRINKLE
ACTIVITY HAS MOVED SE OF THE REGION. AFTER A BRIEF RESPITE THROUGH
LATE THIS EVENING...SEVERAL CONVECTION ALLOWING MODELS AS WELL AS
HRRR/NAM ARE INDICATING SHOWERS RE-DEVELOPING ACROSS SW ZONES LATE
TONIGHT INTO SUNDAY MORNING. FORCING APPEARS TO BE QUITE SUBTLE
(THETA-E ADVECTION/FRONTOGENIC)...SO HAVE ONLY RAISED POPS TO HIGH
CHANCE. WILL HAVE TO WATCH THIS ACTIVITY OVERNIGHT...WITH
POTENTIAL FOR SOME EMBEDDED HEAVIER SHOWERS IF IT MAKES IT THIS
FAR NORTH. LOWS WILL FALL INTO THE 50S...WITH THE WARMEST SPOTS IN
AND AROUND THE NYC METRO AREA.

&&

.SHORT TERM /6 AM SUNDAY MORNING THROUGH SUNDAY NIGHT/...
A WARM FRONT SOUTH OF THE REGION WILL APPROACH THE AREA SUNDAY AND 
SUNDAY NIGHT. SKIES WILL REMAIN CLOUDY WITH AN INCREASING THREAT
OF SHOWERS THROUGH THE DAY. WILL STILL LIMIT POPS TO JUST CHANCE
AT THIS TIME...DUE TO THE DIFFICULTY IN TIMING AND PLACEMENT OF
ANY SHOWER ACTIVITY.

MOISTURE CONTINUES TO INCREASE SUNDAY NIGHT AS A SHORTWAVE
APPROACHES ALONG THE WARM FRONT. WOULD EXPECT LIGHT RAIN OR
DRIZZLE ALONG WITH AREAS OF FOG TO DEVELOP.

TEMPERATURES ON SUNDAY WILL BE SLIGHTLY BELOW NORMAL DUE TO CLOUD
COVER. EXPECT HIGHS IN THE LOWER AND MIDDLE 60S. SUNDAY
NIGHT...LOWS WILL BE MILD WITH TEMPERATURES ONLY FALLING INTO THE
MIDDLE AND UPPER 50S TO NEAR 60.

&&

.LONG TERM /MONDAY 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. 

MODELS IN DECENT AGREEMENT WITH A SPLIT UPPER FLOW ON MONDAY...WITH 
WEAK SHORTWAVE ENERGY OVER THE MID MISSISSIPPI RIVER 
VALLEY...TRACKING SOUTH OF THE REGION ON MONDAY. THE RESULTANT S/SW 
FLOW SHOULD ALLOW FOR WARM FRONTAL PASSAGE MONDAY MORNING...IF NOT 
SOONER. WITH SURGE OF A MORE UNSTABLE AIRMASS...THUNDERSTORMS ARE 
POSSIBLE WITH THE WARM FRONTAL PASSAGE MON MORNING. THEN ONCE IN THE 
WARM SECTOR MON AFTERNOON...THERE IS POTENTIAL FOR ISOLATED TO 
SCATTERED AFTERNOON CONVECTION WITH WEAK SHORTWAVE FORCING/THERMAL 
TROUGHING. 

ON TUESDAY...MODELS CONTINUE IN FAIRLY GOOD AGREEMENT WITH AN 
UNSEASONABLY WARM AND HUMID AIR MASS WORKING INTO THE REGION. 12Z 
GFS PUSHES A BACKDOOR COLD FRONT SOUTH OF THE REGION BY TUESDAY 
MORNING...BUT MAJORITY OF GUIDANCE HOLDS OFF ON THIS TILL LATE 
DAY/NIGHT. DEPENDING ON THE TIMING OF THE FRONTAL 
BOUNDARY...FAVORABLE INSTABILITY AND WIND FIELDS PRESENT THE 
POTENTIAL FOR SOME STRONG TO SEVERE CONVECTION AHEAD/ALONG THIS 
BOUNDARY TUESDAY AFTERNOON/EVENING. 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 FORECASTED.

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 /00Z SUNDAY THROUGH THURSDAY/...
HIGH PRESSURE REMAINS EAST OF THE REGION FROM EASTERN CANADA TO OFF 
CAPE COD. MEANWHILE A FRONTAL BOUNDARY NEARLY STATIONARY FROM THE 
OHIO VALLEY TO THE MID ATLANTIC COAST WILL MOVE VERY SLOWLY 
NORTHWARD AS A WARM FRONT SUNDAY.

VFR WITH PERIODS OF LIGHT RAIN POSSIBLE THROUGH 09Z. MVFR CEILINGS 
DEVELOP TOWARD MORNING...09Z TO 10Z...WITH PERIODS OF LIGHT RAIN 
STILL POSSIBLE. MVFR CEILINGS AND VISIBILITIES MORE LIKELY FROM LATE 
SUNDAY MORNING INTO THE AFTERNOON WITH THE BEST CHANCE OF LIGHT RAIN.

SOUTH TO SOUTHEAST WIND 10 KT OR LESS THROUGH THE FORECAST PERIOD.

.OUTLOOK FOR 00Z MONDAY THROUGH THURSDAY...

.SUNDAY NIGHT...MVFR...POSSIBLY IFR CONDITIONS...IN LIGHT RAIN AND 
FOG.

.MONDAY...IMPROVEMENT TO VFR BY MID TO LATE MORNING. SCATTERED  
SHOWERS...AND ISOLATED THUNDERSTORMS WITH BRIEF MVFR CONDS 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.

&&

.MARINE...
HIGH PRESSURE EAST OF THE WATERS CONTINUES TO MOVE OFFSHORE. THIS 
WILL RESULT IN CONDITIONS REMAINING BELOW SCA LEVELS TONIGHT. 

A WARM FRONT SOUTH OF THE WATERS WILL APPROACH TONIGHT INTO SUNDAY
NIGHT...RESULTING IN A STRENGTHENING SE FLOW. SEAS WILL GRADUALLY
INCREASE TONIGHT INTO SUNDAY TO 5 FT. WAVEWATCH HAS SEAS REACHING
6 FT...HOWEVER AT THIS TIME...I AM THINKING IT MAY BE A LITTLE TOO
HIGH SO HAVE CAPPED SEAS AT 5 FT. WITH SEAS REACHING 5 FT...WILL
BE GOING WITH A SMALL CRAFT ADVISORY FOR THE OCEAN WATERS FROM
SANDY HOOK NJ TO MORICHES INLET NY STARTING SUNDAY MORNING AND
CONTINUING THROUGH SUNDAY NIGHT. FOR THE WATERS FROM MORICHES
INLET NY TO MONTAUK NY...THE SCA WILL START AT NOON ON SUNDAY AND
ALSO RUN THROUGH SUNDAY NIGHT. AN OCCASIONAL GUST TO 25 KT CAN NOT
BE RULED DURING THIS TIMEFRAME.

SCA OCEAN SEAS ARE LIKELY BY MONDAY MORNING WITH A PERSISTENT SE 
FLOW AHEAD OF AN APPROACHING WARM FRONT. THE WARM FRONT SHOULD MOVE 
NORTH OF THE WATERS MONDAY...AND SHOULD REMAIN TO THE NORTH THROUGH 
TUESDAY. THE FRONT WILL LIKELY REMAIN IN THE VICINITY OF THE WATERS 
THROUGH MID WEEK...POSSIBLY SAGGING SOUTH OF THE WATERS LATE TUESDAY 
AND THEN BACK NORTH ON THURSDAY.

ONCE THE WARM FRONT MOVES NORTH ON MONDAY A LONG FETCH SOUTHERLY 
FLOW WILL MAINTAIN SOUTHERLY SWELLS...AND SHOULD KEEP OCEAN SEAS AT 
SCA LEVELS INTO MID WEEK. MARGINAL SCA WINDS ARE POSSIBLE ON 
MONDAY...BUT WINDS SHOULD BE GENERALLY BELOW SCA LEVELS FOR THE 
REMAINDER OF THE EARLY TO MID WEEK PERIOD. MARGINAL SCA WINDS COULD 
RETURN FOR THURSDAY.

&&

.HYDROLOGY...
NO SIGNIFICANT RAINFALL IS EXPECTED THROUGH SUNDAY NIGHT.

PERIODS OF SHOWERS AND THUNDERSTORMS ARE POSSIBLE MON THROUGH 
FRI...WHICH WOULD BE CAPABLE OF PRODUCING LOCALLY HEAVY RAINFALL. 
THERE IS CURRENTLY A LOW THREAT OF FLASH FLOODING FROM ORGANIZED
SHOWER THUNDERSTORM ACTIVITY DURING THIS TIME PERIOD.

&&

.OKX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
NJ...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 6 AM SUNDAY TO 6 AM EDT MONDAY FOR 
     ANZ353-355.
     SMALL CRAFT ADVISORY FROM NOON SUNDAY TO 6 AM EDT MONDAY FOR 
     ANZ350.

&&

$$
SYNOPSIS...BC/NV
NEAR TERM...
SHORT TERM...BC
LONG TERM...NV
AVIATION...GOODMAN/MET/PW
MARINE...BC/NV
HYDROLOGY...BC/NV