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-- Discussion containing changed information from previous version are highlighted. --
000
FXUS61 KOKX 250302
AFDOKX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NEW YORK NY
1002 PM EST SAT JAN 24 2015

.SYNOPSIS...
RAPIDLY DEEPENING LOW PRESSURE IN THE GULF OF MAINE WILL TRACK UP
INTO THE CANADIAN MARITIMES INTO SUNDAY...WITH A COLD FRONT MOVING
ACROSS THE AREA DURING THE DAY ON SUNDAY. HIGH PRESSURE BUILDS
NORTH OF THE AREA SUNDAY NIGHT. STRONG LOW PRESSURE THEN
APPROACHES MONDAY AND PASSES SOUTHEAST OF THE REGION MONDAY NIGHT
INTO TUESDAY BEFORE CONTINUING NORTHEAST TUESDAY NIGHT AND
WEDNESDAY. A WEAKER SYSTEM THEN PASSES THROUGH THURSDAY NIGHT INTO
FRIDAY.

&&

.NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
        ** BLACK ICE ON UNTREATED SURFACES OVERNIGHT **

PRECIPITATION HAS COME TO AN END OVER THE AREA...AND WITH NEGATIVE
VORTICITY ADVECTION IN THE WAKE OF THE DEPARTING SHORTWAVE THAT
SUPPORTED THE LAST BURST OF SNOW...HAVING SOME CLEARING THIS
EVENING. A MID DECK WILL BUILD BACK IN LATE THIS EVENING/EARLY
OVERNIGHT...THEN EXIT LATE.

MAIN STORY THOUGH IS WITH RESIDUAL WATER ON MOST AREA
ROADWAYS...AND TEMPERATURES FALLING MAINLY INTO THE 20S
OVERNIGHT...EXCEPT TO AT OR JUST BELOW THE FREEZING MARK IN
NYC...EXPECT BLACK ICE TO FORM ON NON-TREATED SURFACES. THIS COULD
MAKE TRAVEL...INCLUDING WALKING...TREACHEROUS IN PLACES OVERNIGHT
INTO EARLY SUNDAY MORNING. A SPECIAL WEATHER STATEMENT HAS BEEN
ISSUED FOR THE DEVELOPMENT OF BLACK ICE ON UNTREATED SURFACES.

&&

.SHORT TERM /6 AM SUNDAY MORNING THROUGH SUNDAY NIGHT/...
SHORT WAVE TROUGH PASSES THROUGH NORTHERN NEW ENGLAND ON
SUNDAY...WITH WEAKENING POLAR FRONT APPROACHING SUNDAY MORNING.
FRONTAL PASSAGE LOOKS DRY...WITH JUST SOME SCT STRATO-CU.

BREEZY AND MOSTLY SUNNY WITH HIGHS SUNDAY TOPPING OUT IN THE MID TO
UPPER 30S.

UPPER TROUGH SLIDES EAST SUN NIGHT WITH POLAR HIGH SLIDING INTO NEW
ENGLAND. THIS SHOULD ALLOW FOR GOOD RADIATIONAL COOLING CONDITIONS
FIRST HALF OF SUNDAY EVENING WITH POTENTIAL FOR TEMPS TO DROP INTO
THE TEENS INTERIOR AND PINE BARRENS AND LOWER 20S NYC METRO. COULD
GET INTO SINGLE DIGITS ACROSS THE INTERIOR VALLEYS IF CLOUDS HOLD
OFF LONG ENOUGH.

THEREAFTER...ALL EYES ON STRONG SHORTWAVE ENERGY DIVING THROUGH THE
CENTRAL PLAINS SUN AND INTO THE SE US SUN NIGHT. THIS WILL HAVE LOW
PRESSURE BEGINNING TO TAKE SHAPE ACROSS THE SE US...WITH POTENTIAL
FOR SOME LIGHT SNOW TO DEVELOP LATE SUN NIGHT INTO MONDAY MORNING
ACROSS AT LEAST SOUTHERN AND WESTERN PORTIONS OF THE TRI-STATE.

&&

.LONG TERM /MONDAY THROUGH SATURDAY/...
NOTE ON LATEST MODEL TRENDS FOR STORM SYSTEM MONDAY-TUESDAY. THE
18Z AND 00Z NAM HAVE MOVED TO A TRACK/IMPACT SIMILAR TO THE 12Z
GFS...WITH MOST OF THE IMPACT E OF THE CT/NY STATE LINE. THE 18Z
GFS THOUGH HAS A SOLUTION SIMILAR TO THE 12Z ECMWF/CMC-GLOBAL/NAM
WITH A POTENTIALLY POTENT STORM IMPACTING THE ENTIRE CWA. NO
CHANGES TO PREVIOUS THINKING...WHICH FOLLOWS BELOW...BASED ON
THESE TRENDS.

MODELS ARE TRENDING FARTHER NW REGARDING A STORM THAT IS PROGGED TO
EMERGE OFF THE CAROLINA COAST DURING MONDAY. AS THE STORM HEADS TO
THE NORTH...AN ASSOCIATED UPPER TROUGH BECOMES STRONGLY NEGATIVELY
TILTED BEFORE A 500 MB LOW CLOSES SOUTH OF US AT SOME POINT LATE
MONDAY NIGHT INTO TUESDAY. THIS WOULD DRAW THE STORM CLOSER TOWARDS
IT...EFFECTIVELY SLOWING DOWN ITS PROGRESS TO THE NE IN SPITE OF A
BLOCKING LOW OVER THE CANADIAN MARITIMES MOVING AWAY.

HEAVY SNOW AND STRONG WINDS ARE BECOMING INCREASINGLY LIKELY FOR AT
LEAST EASTERN PORTIONS OF THE CWA. WITH THE UPPER LOW CLOSING OFF
AND DEEPENING OF THE STORM...MESOSCALE BANDING BECOMES MORE LIKELY
AS WELL...BUT IT IS VERY DIFFICULT TO SAY THIS FAR OUT IN ADVANCE
WHERE IT WOULD SET UP. BUT BASED THE MID LEVEL FRONTOGENESIS AND
DEFORMATION THAT MODELS ARE SHOWING...BANDED PRECIPITATION WOULD
MOVE AT LEAST IN THE VICINITY OF THE CWA...PERHAPS LATE MONDAY
NIGHT INTO TUESDAY MORNING. PRECIPITATION TYPE LOOKS LIKE TO BE
ALL SNOW. RIGHT NOW ONLY A SLIGHT CHANCE THAT WARM AIR GETS
WRAPPED INTO THIS SYSTEM AND CAUSES MIXED PRECIPITATION TYPES FOR
EASTERN SECTIONS. SHOULD MODELS CONTINUE THE NW TREND OF THE
STORM`S TRACK...PRECIPITATION TYPE ISSUES COULD BE A BIGGER
CONCERN. WHAT IS MORE CERTAIN IS THAT A COLD AIR MASS WILL ALREADY
BE IN PLACE WITH HIGH PRESSURE SHIFTING THROUGH SE CANADA MONDAY
INTO TUESDAY...PROMOTING PRECIPITATION TYPE OF SNOW.

DID NOT WANT TO TREND UPWARD TOO MUCH REGARDING POPS AND TOO HIGH
WITH QPF/SNOW TOTALS AT THIS POINT AS LIKELY POPS ARE NOT
CURRENTLY FORECAST UNTIL THE 5TH PERIOD...BUT WENT FAIRLY CLOSE TO
RFC AND WPC GUIDANCE...WHICH SEEMS LIKE A GOOD COMPROMISE FROM THE
HIGH QPF OUTPUT FROM ECMWF AND NAM...AND THE OTHER MODELS THAT DO
NOT SHOW AS MUCH. BUT BASED ON THE NW TREND OF THE STORM...DID
MAKE SOME UPWARD ADJUSTMENTS MAINLY WEST OF EASTERN LONG ISLAND
AND SE CT. FORECAST WINDS DURING THIS STORM COULD BE ON THE
CONSERVATIVE SIDE AS WELL...BUT FOR NOW...THINKING IS THAT EASTERN
AND OTHER COASTAL SECTIONS HAVE A DECENT CHANCE OF SEEING GUSTS
OVER 40 MPH. TOO EARLY FOR ANY HEADLINES REGARDING THE SNOW AND
WIND POTENTIAL...BUT WILL ADDRESS AT LEAST THE SNOW ASPECT IN THE
HWO AS WARNING CRITERIA SNOWFALL FOR AT LEAST SOMEWHERE IN THE CWA
IS INCREASING IN LIKELIHOOD.

BEHIND THE STORM...DRY WEATHER WEDNESDAY AND THURSDAY...THEN A
WEAKER LOW AFFECTS US THURSDAY NIGHT INTO FRIDAY. CAPPED POPS A
CHANCE FOR SNOW...WITH PRECIPITATION MORE LIKELY TO BE SNOW...BUT
MIXED PRECIPITATION NOT OUT OF THE QUESTION.

&&

.AVIATION /03Z SUNDAY THROUGH THURSDAY/...
** HIGH IMPACT SNOW AND WIND EVENT POSSIBLE LATE MONDAY INTO
TUESDAY NIGHT...SEE OUTLOOK FOR DETAILS **

LOW PRESSURE TRACKS THROUGH THE WESTERN CANADIAN MARITIME
PROVINCES OVERNIGHT. A COLD FRONT CROSSES THE AREA ON SUNDAY.

VFR THROUGH THE TAF PERIOD.

WINDS ARE MAINLY WNW AROUND 10-15KT...WITH GUSTS TO AROUND 20KT
THIS EVENING. WINDS BACK TO THE W OVERNIGHT AT 5-10KT THROUGHOUT.
WNW WINDS G15-20KT BY LATE SUNDAY MORNING/EARLY AFTERNOON. WINDS
THEN VEER TO THE NW AND THE GUSTS ABATE BY LATE AFTERNOON.

.OUTLOOK FOR 00Z MONDAY THROUGH THURSDAY...
.SUNDAY EVENING...VFR.
.LATE SUNDAY NIGHT/MONDAY MORNING. MVFR POSSIBLE IN -SN. E-NE
WINDS G20-25KT POSSIBLE.
.MONDAY AFTERNOON-TUESDAY NIGHT...IFR/LIFR CONDITIONS LIKELY IN
SNOW...HIGHEST PROBABILITIES AT EASTERN TERMINALS. POTENTIAL FOR
HEAVY SNOW WITH NE-N WINDS G35-45 KT.
.WEDNESDAY...VFR. NW WINDS G25-35KT POSSIBLE.
.WEDNESDAY NIGHT-THURSDAY...VFR.

&&

.MARINE...
GALE CONDITIONS APPEAR TO HAVE COME TO AN END ON ANZ-350...SO HAVE
CONVERTED THE GALE TO AN SCA THERE...WITH THE SAME END TIME AS
THE EXISTING SCA ELSEWHERE...22Z SUNDAY.

MARGINAL SCA CONDITIONS WILL PERSIST ACROSS MOST WATERS THROUGH
SUN AFT...WITH HIGHEST LIKELIHOOD THIS EVENING INTO SUNDAY
MORNING. SEAS 4 TO 10 FT ON THE OCEAN WATERS...HIGHEST EAST OF
MORICHES INLET OVERNIGHT.

WINDS EXPECTED TO GRADUALLY FALL BELOW SCA SUN AFTERNOON INTO
SUNDAY EVENING...AND SEAS ON THE COASTAL OCEAN WATERS FALLING
BELOW SCA LEVELS FOR PROBABLY AT LEAST A BRIEF PERIOD SUN NIGHT.

WINDS INCREASE MONDAY THROUGH TUESDAY WITH A STRONG STORM FORECAST
TO PASS TO THE SOUTHEAST. WILL PROBABLY NEED A GALE WATCH...AND
BASED ON MODEL TRENDS...STORM FORCE WINDS ARE NOT OUT OF THE
QUESTION. WILL ADDRESS GALE POTENTIAL IN THE HWO. WINDS AND SEAS
THEN DIMINISH WEDS AND THURS AS THE STORM MOVES FARTHER OUT TO SEA
AND A HIGH PRESSURE RIDGE APPROACHES FROM THE WEST.

&&

.HYDROLOGY...
DRY INTO SUNDAY EVENING...THEN LIGHT LIQUID EQUIVALENT FALLING AS
SNOW POSSIBLE FROM LATE SUNDAY NIGHT INTO MONDAY.

CURRENT FORECAST HAS ANYWHERE FROM AS LITTLE AS AROUND A TENTH OF
AN INCH OF LIQUID EQUIVALENT PRECIPITATION OVER FAR W ORANGE
COUNTY...TO A LITTLE OVER AN INCH OVER EASTERN LONG ISLAND AND SE
CT...IN ASSOCIATION WITH STORM AFFECTING THE REGION MONDAY
AFTERNOON THROUGH TUESDAY. PRECIPITATION TYPE HOWEVER DOES APPEAR
TO BE MOSTLY ALL SNOW...REDUCING ADVERSE HYDROLOGIC IMPACTS DURING
THE STORM. THERE IS STILL UNCERTAINTY WITH THESE AMOUNTS.

ICE ON THE WALLKILL AND YANTIC RIVERS IS CAUSING MINOR
FLUCTUATIONS IN RIVER LEVELS AT THIS TIME.

&&

.TIDES/COASTAL FLOODING...
A POTENTIAL INTENSE COASTAL STORM COULD BRING MINOR TO LOCALLY
MODERATE COASTAL IMPACTS TO THE REGION MONDAY NIGHT INTO TUESDAY
MORNING.

&&

.OKX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
NJ...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 5 PM EST SUNDAY FOR ANZ330-335-338-
     340-345-350-353-355.

&&

$$

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