Area Forecast Discussion
Issued by NWS Upton, NY

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000
FXUS61 KOKX 062357
AFDOKX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NEW YORK NY
657 PM EST SAT FEB 6 2016

.SYNOPSIS...
HIGH PRESSURE REMAINS OVER THE REGION THROUGH SUNDAY.
INTENSIFYING LOW PRESSURE ALONG THE SOUTHEAST US COAST WILL TRACK
NORTHEAST...MOVING SOUTHEAST OF THE REGION SUNDAY NIGHT INTO
MONDAY. AN ACTIVE WINTER PATTERN WILL CONTINUE THROUGH MUCH OF
NEXT WEEK AS SEVERAL WAVES OF LOW PRESSURE MAY IMPACT THE REGION.
HIGH PRESSURE MAY RETURN AT THE END OF THE WEEK.

&&

.NEAR TERM /THROUGH SUNDAY/...
HIGH PRESSURE SETTLES TO THE SOUTH TONIGHT. JUST SOME HIGH CLOUDS
STREAMING ACROSS AND LATEST SATELLITE TRENDS SHOW THEY ARE MOVING
EAST AND THINNING SOMEWHAT. EXPECT THIS TREND TO CONTINUE THROUGH
THE EVENING WITH MOSTLY CLEAR SKIES OVERNIGHT.

WINDS SHOULD BECOME LIGHT AND WITH MOSTLY CLEAR CONDITIONS...LOWS
SHOULD DROP WELL INTO THE TEENS INLAND AND LOWER AND MIDDLE 20S
FOR MOST OTHER LOCATIONS. SOME LOW 30S POSSIBLE IN THE NYC METRO.

FOR SUNDAY...A MOSTLY SUNNY SKY CONDITION WITH JUST SOME HIGH CLOUDS
AND WEAK WARM AIR ADVECTION ON SW WINDS WILL HELP TEMPS RISE
CLOSE TO SEASONAL NORMS.

&&

.SHORT TERM /SUNDAY NIGHT THROUGH MONDAY/...
SPLIT FLOW WITH MODEL IN GENERAL AGREEMENT WITH A CLOSED UPPER LOW
OFF THE SE US COAST SUN EVENING PIVOTING NE SUN NIGHT TO SE OF THE
40/70 BENCHMARK MONDAY MORNING. MEANWHILE A SECOND LARGER CLOSED LOW
DEVELOPING LOW DIGS INTO THE EASTERN 1/2 OF THE COUNTRY THROUGH THE
GREAT LAKES SUNDAY NIGHT INTO MONDAY.

THE INTERACTION BETWEEN THESE TWO SYSTEMS CONTINUES TO RESULT IN
SUBTLE DIFFERENCES (150 MILE SPREAD) IN TRACK OF AN INTENSIFYING LOW
PRESSURE SYSTEM AS IT MOVES FROM OFF THE NC COAST SUN EVENING AND
THEN SE OF THE 40/70 LAT/LON BENCHMARK ON MONDAY. THIS IS
ACCENTUATING DIFFERENCES IN THE WESTERN EXTENT OF THE DEFORMATION
BANDING AND PRECIPITATION SHIELD...WITH SNOWFALL VARYING ANYWHERE
FROM A TRACE TO INCH FROM W TO E (GFS/ECMWF)...OR TRACE TO 2
INCHES WEST TO 2 TO 4 INCHES EAST (GEM/NAM). OVERALL...A SLIGHT
EASTWARD AND DRIER TREND HAS BEEN NOTED WITH THE 12Z GUIDANCE
VERSUS 00Z.

IN TERMS OF ENSEMBLES...WESTERN LYING 15Z SREF MEAN IS HOLDING
FIRM WITH AROUND 1/2 TO 1 INCH QPF ACROSS THE REGION WITH MEAN
LYING IN THE MIDDLE OF A TRI- MODAL PATTERN. MEANWHILE 12Z GEFS
HAS MEAN OF .05 TO .1 INCH QPF AREAWIDE...WHICH IS BETWEEN THE
STRONG CLUSTERING AROUND THE OPERATIONAL GFS OF ONLY A FEW
HUNDREDTHS OF AN INCH AREA WIDE...TO A HANDFUL OF MEMBERS WITH
1/4 TO 1/2 INCH QPF.

00Z AND 12Z SBU ENSEMBLE SENSITIVITY INDICATING ENSEMBLE SPREAD
IS ON THE NW SIDE OF THE GEFS/ECMWF/CMC ENSEMBLE MEANS FOR THE
LOW TRACK...WITH SENSITIVITY LYING IN THE STRENGTH AND
INTERACTION OF THE AFORE MENTIONED UPPER LOWS. THIS NW SPREAD
PATTERN...HAS MANY TIMES FAVORED WESTERN MOST SOLUTIONS OR
WESTWARD TREND IN LOW PRESSURE TRACK.

BASED ON THE ABOVE...HESITANT TO MAKE MANY CHANGES TO THE CURRENT
FORECAST...PARTICULARLY TOWARDS THE DRIER DETERMINISTIC TREND. A
BLEND OF DETERMINISTIC AND ENSEMBLE QPF PROBABILITIES INDICATING
INCREASING LIKELIHOOD FOR LIGHT PRECIPITATION TO DEVELOP LATE
SUNDAY NIGHT INTO MONDAY MORNING EAST OF NYC AND HUDSON RIVER.
LOWER PROBABILITIES FOR MEASURABLE PRECIPITATION WEST OF THE NYC
METRO AND HUDSON RIVER. PRECIPITATION SHOULD MAINLY BE IN THE FORM
OF SNOW...BUT MAY INITIALLY START AS A MIX WITH RAIN ACROSS
EASTERN LONG ISLAND DUE TO WARM BOUNDARY LAYER.

WILL CONTINUE WITH A GOING FORECAST FOR LATE SUNDAY NIGHT THROUGH
MONDAY WITH...

A LIKELY SCENARIO OF A DUSTING TO COUPLE INCHES ACROSS NYC METRO
AND POINTS WEST AND 2 TO 4 INCHES TOWARDS EASTERN LONG ISLAND AND
SE CT.

A CHANCE SCENARIO FOR A WESTWARD SHIFT...AND DOUBLING OF THESE
AMOUNTS.

&&

.LONG TERM /MONDAY NIGHT THROUGH SATURDAY/...
CONFIDENCE THIS PERIOD IS LOW AS MODELS AND ENSEMBLES HAVE NOT COME
INTO BETTER AGREEMENT WITH A POTENTIALLY ACTIVE WINTER PATTERN FOR
THE MIDDLE OF NEXT WEEK. INTENSE OFFSHORE LOW WILL CONTINUE MOVING
FURTHER NE AWAY FROM COAST MONDAY NIGHT. RIGHT BEHIND THIS SYSTEM IS
THE CONTINUATION OF A VERY ANOMALOUS PATTERN. BASED ON THE 12Z
GEFS...THE WESTERN NORTH AMERICA RIDGING HEIGHT ANOMALIES ARE
BETWEEN 2 AND 3 SD ABOVE NORMAL. THE LONGWAVE TROUGH DIGGING INTO
THE EASTERN STATES IS BETWEEN 3 AND 4 SD BELOW NORMAL. THIS TYPE OF
PATTERN IS USUALLY CAUSE FOR CONCERN AND MODELS AND ENSEMBLES ARE
SHOWING QUITE A LARGE SPREAD WITH IMPORTANT FEATURES AT THE SURFACE
AND ALOFT. SOME OF THIS COULD BE WITH HOW THEY HANDLE THE FIRST LOW
THAT MOVES AWAY FROM THE COAST MONDAY NIGHT.

MONDAY NIGHT INTO TUESDAY NIGHT...A VERY ENERGETIC LONGWAVE TROUGH
SETS UP OVER THE EASTERN STATES. A PARENT LOW IS PROGGED TO MOVE
ACROSS THE LAKES...TRANSFERRING SOMEWHERE NEAR THE MIDDLE ATLANTIC
COAST. THIS NEW WAVE OF LOW PRESSURE WILL THEN MOVE ENE AWAY FROM
THE COAST TO SOMEWHERE IN THE VICINITY OF OF THE 40/70 BENCHMARK.
THERE IS A GENERAL AGREEMENT WITH THIS AMONG THE DETERMINISTIC
MODELS...BUT THEY VARY IN HOW PRECIPITATION IS GENERATED DUE TO
PLACEMENT OF UPPER LEVEL ENERGY AND AMPLITUDE OF THE UPPER LEVEL
TROUGH. THEY SEEM TO BE KEYING ON AN INVERTED TROUGH TYPE
SIGNATURE. THE 12Z GFS/GEFS/CMC/CMC ENSEMBLE SEEM TO HAVE THIS
SETTING UP NEAR THE AREA FOR ACCUMULATING SNOW TUESDAY INTO
WEDNESDAY. THE 12Z ECMWF HAS THIS SETTING UP A BIT FURTHER SOUTH
AWAY FROM OUR CWA. THE 15Z SREF MEAN IS SIMILAR TO THE ECMWF IDEA
AS WELL AS THE 12Z NAM. THERE IS QUITE A BIT OF ENERGY WITHIN THIS
TROUGH AND SUBTLE CHANGES COULD MAKE A DIFFERENCE WHERE BEST LIFT
SETS UP. MODELS HAVE ALSO SHOWN PRETTY DRASTIC CHANGES WITH
IMPORTANT DYNAMICS OVER THE LAST FEW WEEKS...WHICH LEADS TO A
LOWER THAN NORMAL CONFIDENCE FOR THIS TIME PERIOD.

WILL HOLD ONTO LIKELY POPS THROUGH THIS TIME FRAME. FEEL CONTINUITY
IS THE WAY TO GO HERE AND HOPEFULLY AS WE GET CLOSER...WE WILL HAVE
A BETTER IDEA FOR WHERE THE INVERTED TROUGH AND BEST LIFT FROM UPPER
ENERGY WILL SET UP. THE TAKE HOME MESSAGE IS ACCUMULATING LIGHT SNOW
IS POSSIBLE AT SOME POINT MONDAY NIGHT THROUGH TUESDAY NIGHT PERIOD.

WEDNESDAY THROUGH THURSDAY...LOW PRESSURE MOVES FURTHER NE ON
WEDNESDAY...BUT ANOMALOUS TROUGH IS LIKELY TO REMAIN OVERHEAD.
CANNOT RULE OUT LIGHT SNOW WEDNESDAY...BUT FOR NOW IT APPEARS BEST
LIFT SHIFTS EAST OF THE AREA. UPPER TROF AXIS SHIFTS EAST THURSDAY.
POPS TAPER DOWN TO CHANCE WEDNESDAY AND THEN SLIGHT CHANCE ON
THURSDAY.

FRIDAY THROUGH SATURDAY...AN ARCTIC COLD FRONT CROSSES THE REGION
FRIDAY INTO FRIDAY NIGHT AS DEEP UPPER LOW SETS UP ACROSS SOUTHEAST
CANADA. THE FRONT SHOULD MOVE THROUGH DRY AS BEST MOISTURE AXIS HAS
SHIFTED OFFSHORE FROM EARLIER WEEK ACTIVITY. ARCTIC HIGH BUILDS INTO
THE AREA SATURDAY. THE 12Z ECMWF HAS 850 HPA TEMPS DROPPING TO
BETWEEN -22C TO -26C.

FORECAST TEMPERATURES ARE BELOW NORMAL THROUGHOUT THE LONG
TERM...WITH INCREASING PROBABILITY OF A SHOT OF ARCTIC AIR AND WELL
BELOW NORMAL TEMPERATURES AT THE WEEK AND NEXT WEEKEND.

&&

.AVIATION /00Z SUNDAY THROUGH THURSDAY/...
HIGH PRESSURE SLOWLY RETREATS TO THE NORTHEAST INTO SUNDAY
EVENING.

VFR THROUGH THE TAF PERIOD.

WINDS BECOME LIGHT AND VARIABLE THROUGHOUT TONIGHT...AND SHOULD
REMAIN SO INTO SUNDAY AFTERNOON. WINDS BECOME SE/E THEN ENE-NE AT
UNDER 10 KT LATE SUNDAY AFTERNOON/EARLY SUNDAY EVENING.

.OUTLOOK FOR 00Z MONDAY THROUGH THURSDAY...
.SUNDAY NIGHT...VFR IN THE EVENING...THEN MVFR OR LOWER POSSIBLE
LATE...ESPECIALLY AT EASTERN TERMINALS IN -SN...POSSIBLY MIXED
WITH RAIN AT THE START FOR SOUTHERN/EASTERN TERMINALS. NE WINDS
G20-30+KT POSSIBLE. HIGHEST GUSTS EASTERN CT/LONG ISLAND
TERMINALS.
.MONDAY...MVFR OR LOWER LIKELY IN SNOW. NE-N WINDS G20-30KT
WESTERN TERMINALS AND 30-40KT EASTERN TERMINALS POSSIBLE.
.MONDAY NIGHT-TUESDAY NIGHT...MVFR OR LOWER LIKELY IN SNOW. MIXED
PRECIPITATION POSSIBLE NEAR THE COAST DURING THE DAY ON TUESDAY.
N-NE WINDS G15-25KT POSSIBLE MONDAY NIGHT-TUESDAY.
.WEDNESDAY THROUGH THURSDAY...SUB-VFR POSSIBLE IN -SN. W-NW WINDS
G20-25KT POSSIBLE WEDNESDAY NIGHT-THURSDAY.

&&

.MARINE...
FORECAST ON THE WATERS REMAINS ON TRACK THIS EVENING AS HIGH
PRESSURE SETTLES SOUTH.

SUB-ADVISORY CONDITIONS WILL PREVAIL ON ALL WATERS THROUGH SUNDAY
WITH HIGH PRESSURE TO OUR SOUTH. WINDS GUSTS AROUND 20 KT LIKELY
THROUGH THIS EVENING ON THE OCEAN AND EASTERN LONG ISLAND...WITH
SEAS BUILDING TO AROUND 4 FT ON THE EASTERN OCEAN WATERS.

AN AREA OF LOW PRES DEVELOPS OFF THE SE COAST SUNDAY...INTENSIFYING
AS IT TRACKS NE. THE PRES GRADIENT WILL TIGHTEN SUN NIGHT WITH
GALE FORCE WINDS EXPECTED ACROSS CENTRAL AND EASTERN OCEAN WATERS
AFTER MIDNIGHT AND CONTINUING INTO MONDAY. POTENTIAL FOR GALES ON
THE WESTERN OCEAN WATERS AND EASTERN LONG ISLAND SOUND/BAYS. SCA
CONDITIONS EXPECTED ON REMAINDER OF THE WATERS. THERE IS STILL
SOME UNCERTAINTY WITH THE TRACK OF LOW PRESSURE...AND IF IT TRACKS
CLOSER TO THE COAST...THE GALE THREAT WILL MOVE WESTWARD.

SCA IS LIKELY ON MOST WATERS TUESDAY THROUGH THURSDAY AS SEVERAL
WAVES OF LOW PRESSURE ARE FORECAST TO PASS NEAR THE WATERS. WINDS
MAY TEMPORARILY DECREASE TUE NIGHT INTO WEDNESDAY...BUT SEAS ON THE
OCEAN WILL REMAIN ABOVE 5 FT. WINDS THEN INCREASE ABOVE SCA LATE
WEDNESDAY INTO THURSDAY.

&&

.HYDROLOGY...
WIDESPREAD LIGHT PRECIPITATION IS LIKELY LATE SUNDAY NIGHT THRU
MON...WITH LOW PROB FOR MODERATE PRECIPITATION. MOST IF NOT ALL
OF THE PRECIPITATION THAT FALLS LIKELY TO BE IN THE FORM OF SNOW
AT THIS TIME.

WIDESPREAD PRECIPITATION IS POSSIBLE MON NIGHT THROUGH TUESDAY
NIGHT. THE PRECIPITATION THAT FALLS SHOULD BE IN THE FORM OF SNOW.

&&

.TIDES/COASTAL FLOODING...
POTENTIAL FOR MINOR COASTAL IMPACTS MONDAY INTO MIDWEEK WITH A NEW
MOON ON MONDAY AND A SERIES OF LOW PRESSURES AFFECTING THE REGION.

AN INTENSIFYING LOW PRESSURE WILL HAVE NE/N WINDS INCREASING TO
POTENTIALLY GALE FORCE SUNDAY NIGHT AND CONTINUING INTO MONDAY.
BASED ON A TRACK OF INTENSIFYING LOW THAT SHOULD BE SE OF THE
40/70 LAT/LON BENCHMARK AND COLD AIR DAMMING SIGNATURE...WOULD
EXPECT POTENTIAL FOR WINDS TO BE BACKED MORE TO THE N THAN NE.
THIS WOULD FAVOR THE LOWER SURGE GUIDANCE FOR MONDAY AND MONDAY
NIGHT HIGH TIDE CYCLES...WHICH WOULD KEEP IMPACTS MINOR AND
LIKELY LIMITED TO THE MOST VULNERABLE LOCALES. WILL HAVE TO
MONITOR.

AS WE HEAD INTO TUESDAYS HIGH TIDE CYCLES...POTENTIAL EXISTS FOR
WINDS TO VEER MORE TO THE NE AS ADDITIONAL WAVE/S OF LOW PRESSURE
TRACK TO THE SOUTH OF THE REGION. THE SPRING ASTRONOMICAL TIDES
AND MULTI-TIDAL CYCLE NATURE OF THE EVENT WILL FAVOR ADDITIONAL
MINOR FLOODING...WITH POTENTIAL FOR WIDESPREAD MINOR TO MODERATE
IMPACTS IN THE BACK BAY AREAS TUESDAY AND WEDNESDAY.

&&

.OKX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
NJ...NONE.
MARINE...SMALL CRAFT ADVISORY FROM MIDNIGHT SUNDAY NIGHT TO 6 PM EST
     MONDAY FOR ANZ335-338-345.
     GALE WATCH FROM LATE SUNDAY NIGHT THROUGH MONDAY AFTERNOON FOR
     ANZ330-340-355.
     GALE WARNING FROM MIDNIGHT SUNDAY NIGHT TO 6 PM EST MONDAY FOR
     ANZ350-353.

&&

$$

SYNOPSIS...DS/NV
NEAR TERM...DS/NV
SHORT TERM...NV
LONG TERM...DS
AVIATION...MALOIT
MARINE...DS/NV
HYDROLOGY...DS/NV
TIDES/COASTAL FLOODING...NV


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