-- Discussion containing changed information from previous version are highlighted. --
000
FXUS61 KOKX 191733
AFDOKX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NEW YORK NY
133 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/...
WEAK WAA CAUSING LIGHT RAIN TO PROGRESS ACROSS THE AREA THIS
MORNING. UPDATED POPS TODAY AND TONIGHT BASED ON LATEST RADAR
TRENDS...WITH THE RAIN SHIFTING MORE INTO EASTERN SECTIONS THIS
AFTERNOON. DO NOT SEE MUCH IN THE WAY OF FORCING TONIGHT SO POP
ONLY LOW CHANCE...WITH AREAS OF FOG/DRIZZLE AS LOW LEVELS REMAIN
VERY MOIST.

THERE IS SOME WEAK INSTABILITY ALOFT LATE TONIGHT AND EARLY MON
MORNING...SO MENTIONED ISOLD TSTMS.

HIGHS WILL ONLY REACH THE LOWER 60S TODAY...5-10 DEG BELOW AVG.
LOWS TONIGHT WILL BE NEAR TO SLIGHTLY ABOVE AVG...IN THE MID AND
UPPER 50S.

&&

.SHORT TERM /MONDAY THROUGH TUESDAY/...
THE REGION WILL BE WARM SECTORED ON MONDAY AS A COLD FRONT
APPROACHES FROM THE N. EXPECT AT LEAST PARTIAL CLEARING TO
OCCUR...WHICH WILL DETERMINE AMT OF DAYTIME HEATING/INSTABILITY.
AS FRONT ALIGNS WITH THE FLOW ALOFT WHICH IS RELATIVELY WEAK
/10-20 KT/ AND AS PW INCREASES TO 1.5 INCHES THERE IS POSSIBILITY
OF TRAINING OF SLOW MOVING HEAVY SHOWERS/THUNDERSTORMS WITH
ATTENDANT URBAN FLOODING ISSUES. CONFIDENCE LOW ATTM.

ANY CONVECTION SHOULD WANE MON EVENING AS THE FRONT DROPS THROUGH.
UNCERTAIN JUST HOW FAR S THE BOUNDARY GETS...KEPT CHANCE POP FOR
AFTERNOON SHOWERS/TSTMS ON TUE...MAINLY N AND W OF NYC.

TEMPS WILL BE AROUND 5 DEGREES ABOVE AVG...WITH A NOTICEABLY MORE
HUMID AIR MASS IN PLACE AS WELL.

&&

.LONG TERM /TUESDAY NIGHT 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 /18Z SUNDAY THROUGH FRIDAY/...
-- Changed Discussion --
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.
-- End Changed Discussion --

&&

.MARINE...
HIGH PRESSURE PASSES EAST OF THE WATERS TODAY. AS IT DOES
SO...SOUTHERLY WINDS WILL INCREASE TO 15 TO 20 KT...MAINLY ACROSS
THE OCEAN WATERS. OCEAN SEAS STILL ONLY 2-3 FT...BUT COULD TOUCH 5
FT BY LATE DAY...SO PUSHED START TIME OF OCEAN SCA FORWARD TO 4
PM.

BY TONIGHT...LOW PRESSURE PASSES TO THE NORTH OF THE WATERS. WINDS
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.

WAVE WATCH HAS BEEN RUNNING HIGH...BUT LATEST GUIDANCE HAS CAPTURED THE
TRENDS AND SLOWLY BUILDS SEAS TODAY. MAY UNDERCUT OCEAN SEA FCSTS
SLIGHTLY EARLY IN THE WEEK...BUT SEAS REMAIN RATHER ROUGH THROUGH
MONDAY ON THE OCEAN WATERS DUE TO PERSISTENT SOUTHERLY FETCH AND
SWELLS.

WILL FOLLOW WIND DIRECTION AND SPEED CLIMATOLOGY FOR SEA/WAVE FCSTS
ACROSS LI SOUND AND THE SURROUNDING HARBORS AND BAYS.

&&

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

&&

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

&&

$$
SYNOPSIS...
NEAR TERM...GOODMAN
SHORT TERM...
LONG TERM...
AVIATION...BC
MARINE...
HYDROLOGY...