January 21, 2014 Forecast Discussion

000
FXUS61 KALY 211007
AFDALY

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ALBANY NY
507 AM EST TUE JAN 21 2014

.SYNOPSIS…
AN ARCTIC AIR IS IN PLACE ACROSS THE REGION AND IT WILL REMAIN FOR
THE REMAINDER OF THE WEEK…WITH DANGEROUSLY COLD TEMPERATURES AND
WIND CHILLS. A COASTAL STORM IS DEVELOP ALONG THE MID ATLANTIC
COAST. THIS LOW WILL MOVE NORTHEASTWARD AND STRENGTHEN EVENTUALLY
PASSING WELL SOUTH OF LONG ISLAND AND CAPE COD TONIGHT AND WEDNESDAY
MORNING. ACCUMULATING SNOWS WILL OCCUR MAINLY TO AREAS TO THE SOUTH
AND EAST OF THE CAPITAL DISTRICT…ESPECIALLY AS YOU GET CLOSER TO
THE COAST.

&&

.NEAR TERM /THROUGH TONIGHT/…
WIND CHILLS…

A WIND CHILL ADVISORY REMAINS IN EFFECT UNTIL 11 AM TODAY FOR THE
SOUTHERN ADIRONDACKS AND WESTERN MOHAWK VALLEY.

THE ARCTIC AIRMASS IS IN PLACE. TEMPERATURES HAVE FALLEN TO AROUND
15 DEGREES BELOW ZERO ACROSS THE WESTERN ADIRONDACKS TO TEENS IN THE
MID HUDSON VALLEY. DID CUT BACK ON THE CURRENT WIND CHILL
ADVISORY…HAVE IT EXPIRING AT 11 AM. BY THIS TIME WIND CHILL
READINGS SHOULD NO LONGER BE REACH OE EXCEED THE ADVISORY CRITERIA.

BRUTALLY COLD TONIGHT INTO WEDNESDAY MORNING. HAVE ISSUED A WIND
CHILL WARNING FOR THE SOUTHERN ADIRONDACKS…WESTERN MOHAWK
VALLEY…SCHOHARIE VALLEY AND THE CENTRAL/SOUTHEASTERN CATSKILLS
FOR THIS EVENING THROUGH WEDNESDAY MORNING.

ALSO A WIND CHILL ADVISORY HAS BEEN ISSUED FOR THE REST OF EAST
CENTRAL AND ADJACENT WESTERN NEW ENGLAND…EXCEPT FOR EASTERN
ULSTER…WESTERN DUTCHESS AND SOUTHERN LITCHFIELD FOR THE SAME TIME
PERIOD.

WITH A DEEPENING COASTAL LOW PASSING WELL TO OUR SOUTH AND HIGH
PRESSURE TO OUR WEST THE PRESSURE GRADIENT WILL TIGHTEN ACROSS THE
REGION. COMBINING THE STRENGTHENING WINDS AND FALLING TEMPERATURES
DANGEROUSLY COLD TO LIFE THREATENING WINDS CHILLS WILL DEVELOP.
HAVE KEEP IT SIMPLE AND STARTED THE WARNING AND ADVISORY AT THE
SAME TIME AND RAN IT THROUGH EARLY WEDNESDAY MORNING.

COASTAL STORM…

A WINTER STORM WARNING HAS BEEN ISSUED FOR LITCHFIELD COUNTY FOR 6
TO 10 INCHES OF SNOW…AND A WINTER WEATHER ADVISORY FOR
DUTCHESS…ULSTER…EASTERN COLUMBIA AND BERKSHIRE COUNTIES FOR
GENERALLY 3 TO 7 INCHES. THE HIGHEST TOTAL ARE EXPECTED ACROSS THE
SOUTHERN PORTIONS OF THE COUNTIES CLOSER TO THE COAST AND STORM.
BOTH ARE IN EFFECT FOR THIS AFTERNOON BEGINNING AT 1 PM AS THE
SNOW OVERSPREADS THE AREA AND RUN INTO THE EARLY MORNING HOURS
WEDNESDAY.

A COASTAL STORM IS TAKING SHAPE ALONG THE MID ATLANTIC COAST AS A
VIGOROUS SHORT WAVE DIGS THE UPPER LEVEL TROUGH OVER THE EASTERN
UNITED STATES. PRESSURE ARE FALLING ACROSS THAT REGION. MODEL GUIDANCE
CONTINUES TO TREND DEEPER WITH THE STORM RESULTING IN A TRACK A
BIT CLOSER TO THE COAST AND A BIT SLOWER. THE GFS…NAM AND ECMWF
ARE IN GOOD AGREEMENT WITH THE TRACK OF THE STORM AND THE GEFS
ENSEMBLES MEMBERS ARE TIGHTLY CLUSTERED. THE LOW IS EXPECTED TO
PASS AROUND 150 MILES SOUTHEAST OF CAPE COD 12Z/WEDNESDAY.
GUIDANCE INDICATES FGEN FIELDS QUICKLY INCREASE LATE THIS
AFTERNOON AND EVENING WITH POTENTIAL BANDS LIFTING AS FAR NORTH AS
THE MID HUDSON VALLEY AND SOUTHERN BERKSHIRES. THE PRECIPITATION
SHIELD IS EXPECTED TO REACH THE CAPITAL DISTRICT WITH LIGHT SNOW
THIS EVENING WITH AROUND AN INCH. EXPECTING A TIGHT SNOWFALL
GRADIENT ACROSS THE SOUTHEASTERN PORTION OF THE FORECAST AREA WITH
THE HIGHEST SNOWFALL TOTALS OCCURRING ACROSS THE SOUTHERN PORTIONS
OF THE COUNTIES.

SINCE HAVE AN ARCTIC AIRMASS IN PLACE AND TEMPERATURES WILL BE VERY
COLD THE SNOW TO LIQUID RATIO WILL BE HIGH RESULTING IN LIGHT
FLUFFY SNOW THAT WILL BE EASILY BLOWN AROUND.

&&

.SHORT TERM /WEDNESDAY THROUGH THURSDAY/…
THE COASTAL SYSTEM WILL CONTINUE TO DEEPEN AS IT HEADS OFF TO THE
NORTHEAST TOWARD THE CANADIAN MARITIMES. EVEN COLDER AIR WILL BE
DRAWN INTO THE REGION IN THE WAKE OF THE LOW SETTING TE STAGE FOR
WEDNESDAY TO BE THE COLDEST DAY OF THE WEEK.

IT WILL BE BRUTALLY COLD WEDNESDAY MORNING. WILL HAVE VERY COLD
TEMPERATURES AND BRISK AND GUSTY WINDS OCCURRING ACROSS MOST OF
THE FORECAST AREA ESPECIALLY TOWARD THE COAST. HAVE WIND CHILL
HEADLINES POSTED THROUGH THE MORNING HOURS.

WEDNESDAY NIGHT WILL FEATURE COLDER AIR TEMPERATURES HOWEVER THE
WINDS WILL BE LIGHTER WHICH HAS A HUGE IMPACT ON WIND CHILL
READINGS. WILL LIKELY NEED WIND CHILL ADVISORIES ACROSS THE HIGHER
TERRAIN FOR WEDNESDAY NIGHT INTO THURSDAY MORNING.

SHORT WAVES WILL CONTINUE TO PARADE THROUGH THE LONGWAVE TROUGH
OVER THE REGION. LOW LEVEL FLOW WEDNESDAY NIGHT INTO THURSDAY WILL
BE FAVORABLE FOR LAKE EFFECT SNOW SHOWERS ACROSS CENTRAL NEW YORK
POSSIBLY INTO THE SCHOHARIE VALLEY AND EASTERN CATSKILLS.

&&

.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/…
THE EXTENDED FORECAST CONTINUES TO FEATURE BELOW NORMAL
TEMPERATURES…AND SEVERAL CLIPPERS THAT WILL BRING REINFORCING
SHOTS OF ARCTIC AIR TO THE NORTHEAST.

THE MEAN LONGWAVE TROUGH WILL CONTINUE OVER THE ERN TWO THIRDS OF
THE LOWER 48 WITH AN H500 RIDGE OVER THE WEST COAST AND ERN
PACIFIC. THIS POSITIVE PNA PATTERN HAS BEEN PERSISTENT OF LATE.

THURSDAY NIGHT…BITTERLY COLD AIR WILL ENGULF THE REGION IN THE
WAKE OF A CLIPPER…AS A SFC RIDGE CENTERED OVER THE SRN PLAINS
BUILDS IN BRIEFLY. H850 TEMPS PLUMMET BACK INTO THE -21C TO -25C
RANGE. 1000-500 HPA THICKNESSES FALL BELOW 500 DECAMETERS IN THE
ARCTIC AIR MASS. LOWS ARE FORECASTED TO BE 10 TO 15F BELOW ZERO OVER
THE SRN DACKS….ZERO TO 10F BELOW OVER THE MOHAWK VALLEY…CAPITAL
REGION…LAKE GEORGE SARATOGA REGION…SRN VT…THE
BERKS…SCHOHARIE VALLEY…AND ERN CATSKILLS. TEMPS WILL BE IN THE
ZERO TO 5F RANGE OVER THE SRN TACONICS…MID HUDSON VALLEY AND NW
CT. WINDS IN THE 5 TO 15 MPH RANGE COULD PRODUCE ADVISORY LEVEL
WIND CHILLS OVER THE HIGHER TERRAIN ONCE AGAIN /-15 TO -29F/…AND
WE WILL KEEP MENTION IN THE HWO.

FRIDAY…A COLD AND FAIRLY QUIET DAY IS EXPECTED…EXCEPT FOR SOME
LAKE EFFECT SNOW SHOWERS AND FLURRIES OVER THE WRN MOHAWK VALLEY/WRN
DACKS. THIS LAKE EFFECT ACTIVITY WILL BE ATTRIBUTED TO THE LOW TO
MID LEVEL FLOW BACKING FROM THE NW TO THE W/SW…AS THE SFC HIGH
NUDGES IN FROM THE SOUTHEASTERN STATES. MEANWHILE…THE NEXT
CLIPPER WILL BE APPROACHING FROM THE CANADIAN PRAIRIES AND THE
W-CNTRL GREAT LAKES REGION. MAX TEMPS WILL GENERALLY BE FRIGID IN
THE TEENS WITH SOME SINGLE DIGITS OVER THE SRN DACKS…AND SRN VT.

FRIDAY NIGHT INTO SATURDAY…WARM ADVECTION OCCURS AHEAD OF THE
CLIPPER AND ITS ASSOCIATED WARM FRONT DURING THE NIGHT TIME PERIOD
WITH H850 TEMPS RISING CLOSER TO NORMAL FOR LATE JAN IN THE -10C TO
-15C RANGE. LOWS WILL BE IN THE SINGLE DIGITS AND LOWER TEENS WITH
CLOUDS INCREASING FROM THE W/SW AND SOME THERMAL ADVECTION SNOW
SHOWERS OR LIGHT SNOW NORTHWEST OF THE CAPITAL REGION BY DAYBREAK.
THE EC/GFS/WPC GUIDANCE ARE IN PRETTY GOOD AGREEMENT THAT THE BEST
QG LIFT WITH THE CLIPPER FOR HIGH CHANCE TO LIKELY VALUES FOR A
PERIOD OF LIGHT SNOW WILL BE SATURDAY…AS THE CYCLONE MOVES ACROSS
SRN QUEBEC AND ITS COLD FRONT SWEEPS ACROSS THE REGION. A FEW INCHES
OF SNOW ACCUMULATION WILL BE POSSIBLE. MAX TEMPS MAY RISE INTO THE
20S TO PERHAPS EVEN A FEW 30F READINGS IN THE MID HUDSON VALLEY.

SATURDAY NIGHT…THE COLD FRONT MOVES THROUGH WITH SOME LINGERING
SNOW SHOWERS…AND A REINFORCING SHOT OF ARCTIC AIR. SOME LAKE
EFFECT SNOW MAY KICK IN BRIEFLY OVER THE WRN DACKS. THE LATEST GFS
PLUNGES THE H850 TEMPS BACK DOWN TO -23C OVER NW CT TO NEARLY -30C
OVER THE SRN DACKS BY 12Z SUN. LOWS WILL GENERALLY BE IN THE SINGLE
DIGITS OVER MOST OF THE REGION /SOME BELOW ZERO READINGS IN THE SRN
DACKS/…AND LOWER TEENS OVER THE MID HUDSON VALLEY…AND NW CT.

SUNDAY INTO MONDAY…SOME TIMING DIFFERENCES IN THE MEDIUM RANGE
GUIDANCE ON THE NEXT CLIPPER. SOME WESTERLY UPSLOPE AND LAKE EFFECT
SNOW SHOWERS WILL KEEP SLIGHT AND LOW CHC POPS ACROSS THE REGION
SUN/SUN NIGHT. THE QUESTION WILL BE HOW FAR SOUTH THE CLIPPER DIPS
IN THE LONGWAVE TROUGH. SOME SIGNALS HERE IT WILL DROP S/SE ACROSS
THE OHIO VALLEY AND UPPER MID ATLANTIC REGION…SUNDAY NIGHT INTO
MONDAY…AND MAY PRODUCE SOME LIGHT SNOW FOR MONDAY NIGHT INTO
TUESDAY. A LOT OF MODEL UNCERTAINTY HERE…AND WE HAVE MAINTAINED
SLIGHT CHC POPS FOR MONDAY. TEMPS CONTINUE TO BE BELOW NORMAL THESE
DAY BY 10 TO 15 DEGREES.

&&

.AVIATION /10Z TUESDAY THROUGH SATURDAY/…
HIGH PRESSURE NEAR THE UPPER MIDWEST WILL BRIEFLY RIDGE IN THIS
MORNING. HOWEVER…A STORM SYSTEM WILL MOVE FROM THE MID ATLANTIC
REGION BY DAYBREAK TO WELL SOUTH OF LONG ISLAND IN THE LATE
AFTERNOON AND EARLY EVENING BRINGING SOME SNOWFALL TO PARTS OF
E-CNTRL NY AND WRN NEW ENGLAND.

VFR CONDITIONS ARE EXPECTED TO PREVAIL PRIOR TO NOONTIME AT ALL
THE TAF SITES…AS INITIALLY THE SKIES WILL PARTIALLY CLEAR FROM
KALB NORTHWARD PRIOR TO 12Z…BUT THEN THE CLOUDS WILL START TO
THICKEN AND LOWER FROM KPOU NORTHWARD DURING THE LATE MORNING INTO
THE AFTERNOON.

MVFR/IFR CIGS AND VSBYS ASSOCIATED WITH THE OVER RUNNING SNOWFALL
ARE EXPECTED TO IMPACT KPOU BY ABOUT 20Z…KPSF BY 22Z…AND KALB
BY 01Z/WED. CONFIDENCE IS THE HIGHEST FOR IFR CIGS AND VSBYS FOR
KPOU AT 23Z…AND KPSF BY ABOUT 01Z/WED. KALB IS EXPECTED TO BE
MAINLY MVFR…AND KGFL MAY STAY VFR FOR THE ENTIRE TAF CYCLE.

THE WINDS WILL BE FROM THE NW TO N AT 5-12 KTS THIS MORNING…AND
WEAKEN TO 7 KTS OR LESS BY DAYBREAK. THE WINDS WILL INCREASE FROM
THE NORTH AT AROUND 10 KTS BTWN 22Z/TUE TO 01Z/WED.

OUTLOOK…
WED NIGHT: NO OPERATIONAL IMPACT. NO SIG WX.
THU-FRI NIGHT: LOW OPERATIONAL IMPACT. NO SIG WX.
SAT: MODERATE OPERATIONAL IMPACT. BREEZY. CHANCE OF SN.

&&

.HYDROLOGY…
NO WIDESPREAD HYDRO PROBLEMS ARE EXPECTED THIS WEEK.

AN ARCTIC AIR IS IN PLACE ACROSS THE REGION AND IT WILL REMAIN FOR
THE REMAINDER OF THE WEEK. THIS WILL ALLOW RIVER AND LAKE ICE TO
REFORM AND THICKEN.

A COASTAL STORM WILL BRING ACCUMULATING SNOWS TO AREAS MAINLY TO
AREAS TO THE SOUTH AND EAST OF THE CAPITAL DISTRICT…ESPECIALLY
AS YOU GET CLOSER TO THE COAST THIS AFTERNOON INTO EARLY WEDNESDAY
MORNING. NEXT CHANCES FOR WIDESPREAD PRECIPITATION WILL COME OVER
THE WEEKEND IN THE FORM OF SNOW.

FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES…INCLUDING OBSERVED
AND FORECAST RIVER STAGES AND LAKE ELEVATIONS…PLEASE VISIT THE
ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON OUR WEBSITE.

&&

.ALY WATCHES/WARNINGS/ADVISORIES…
CT…WIND CHILL ADVISORY FROM 6 PM THIS EVENING TO NOON EST
WEDNESDAY FOR CTZ001.
WINTER STORM WARNING FROM 1 PM THIS AFTERNOON TO 6 AM EST
WEDNESDAY FOR CTZ001-013.
NY…WINTER WEATHER ADVISORY FROM 1 PM THIS AFTERNOON TO 6 AM EST
WEDNESDAY FOR NYZ061-063>066.
WIND CHILL WARNING FROM 6 PM THIS EVENING TO NOON EST
WEDNESDAY FOR NYZ032-033-038-042-047-058-063-082.
WIND CHILL ADVISORY FROM 6 PM THIS EVENING TO NOON EST
WEDNESDAY FOR NYZ039>041-043-048>054-059>061-066-083-084.
WIND CHILL ADVISORY UNTIL 11 AM EST THIS MORNING FOR NYZ032-
033-038-042-082.
MA…WINTER WEATHER ADVISORY FROM 1 PM THIS AFTERNOON TO 6 AM EST
WEDNESDAY FOR MAZ001-025.
WIND CHILL ADVISORY FROM 6 PM THIS EVENING TO NOON EST
WEDNESDAY FOR MAZ001-025.
VT…WIND CHILL ADVISORY FROM 6 PM THIS EVENING TO NOON EST
WEDNESDAY FOR VTZ013>015.

&&

$$
SYNOPSIS…IAA
NEAR TERM…IAA/HWJIV
SHORT TERM…IAA
LONG TERM…WASULA
AVIATION…WASULA
HYDROLOGY…IAA

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