January 20, 2014 Forecast Discussion

000
FXUS61 KALY 201511
AFDALY

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ALBANY NY
1011 AM EST MON JAN 20 2014

.SYNOPSIS…
AN ARCTIC COLD FRONT WILL CROSS THE REGION TODAY…USHERING IN A
BITTERLY COLD AIRMASS AND BE ACCOMPANIED BY SOME SNOW SHOWERS.
TEMPERATURES WILL FALL DURING THE AFTERNOON HOURS. THE ARCTIC AIR
IS EXPECTED TO REMAIN IN PLACE FOR THE REMAINDER OF THE WEEK. THE
VERY COLD TEMPERATURES COMBINED WITH WINDS…EVEN LIGHT
WINDS…WILL RESULT IN DANGEROUSLY COLD WIND CHILLS MUCH OF THE
WEEK…ESPECIALLY LATE AT NIGHT AND EARLY IN THE MORNING. IN
ADDITION…A COASTAL STORM MAY BRING ACCUMULATING SNOWFALL TO
AREAS TO THE SOUTH AND EAST OF THE CAPITAL DISTRICT TUESDAY
AFTERNOON AND NIGHT.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/…
AS OF 1011 AM EST…THE WINTER WEATHER ADVISORY FOR SNOW HAS BEEN
ALLOWED TO EXPIRE AT 10 AM FOR NORTHERN HERKIMER AND HAMILTON
COUNTIES. BASED ON SOME OBSERVATIONS AND MOSAIC RADAR
TRENDS…LIGHT SNOW IS OCCURRING ACROSS THE ADVISORY AREA WITH
VERY MINOR ADDITIONAL ACCUMULATION THE REST OF TODAY. LIGHT SNOW
WILL GRADUALLY TAPER OFF THIS AFTERNOON…AS FRIGID ARCTIC AIR
STARTS TO FILTER INTO THE AREA.

ELSEWHERE…UPDATED FORECAST TO SLIGHTLY INCREASE POPS FOR AREAS
WHERE MORE PERSISTENT SNOW SHOWERS HAVE BEEN OCCURRING THIS
MORNING. OBS INDICATING VSBYS BETWEEN 1-2 MILES WHERE HIGHER RADAR
REFLECTIVITIES ARE OCCURRING…SO ANY ADDITIONAL ACCUMULATIONS
WILL BE LIGHT AND GENERALLY A FEW TENTHS OF AN INCH TO PERHAPS AN
INCH IN SOME HIGHER ELEVATION LOCATIONS.

AT THIS TIME…THE ARCTIC BOUNDARY IS SLOWLY DRIFTING SOUTHWARD
ACROSS NORTHERN NEW YORK AND NORTHERN NEW ENGLAND. THIS BOUNDARY
WILL OPEN THE DOOR TO AN ARCTIC AIRMASS THAT WILL AFFECT US THE
ENTIRE WEEK. IT WILL MAKE SOUTHWARD PROGRESS HOWEVER IS NOT
EXPECTED TO CLEAR THE MID HUDSON VALLEY AND LITCHFIELD HILLS UNTIL
LATER THIS AFTERNOON. THIS IS BECAUSE SHORT WAVES MOVING THROUGH
THE LONGWAVE TROUGH SLOW THE SOUTHWARD PROGRESS OF THE BOUNDARY.

RELATIVELY MILD TEMPERATURES ACROSS THE AREA THIS MORNING…HOWEVER
TEMPERATURES WILL FALL DURING THE AFTERNOON AND EVENING ACROSS
MUCH OF THE FORECAST AREA WITH THE PASSAGE OF THE ARCTIC BOUNDARY.
AS THE WINDS SHIFT TO THE SOUTHWEST AS THE BOUNDARY APPROACHES
THEN TO THE NORTHWEST WITH ITS PASSAGE WINDS WILL PICK UP BECOMING
BRISK AND GUSTY ESPECIALLY IN THE WAKE OF THE FRONT.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH WEDNESDAY NIGHT/…
A WIND CHILL ADVISORY HAS BEEN ISSUED FOR 9 AM TONIGHT INTO 11 AM
TUESDAY FOR THE SOUTHERN ADIRONDACKS AND WESTERN MOHAWK VALLEY.

A COASTAL STORM MAY BRING ACCUMULATING SNOWFALL TO AREAS TO THE
SOUTH AND EAST OF THE CAPITAL DISTRICT TUESDAY AFTERNOON AND NIGHT.

TEMPERATURES WILL KEEP DROPPING AND ARE EXPECTED TO BOTTOM OUT
FROM AROUND 15 DEGREES BELOW ZERO ACROSS MUCH OF THE WESTERN
ADIRONDACKS TO AROUND 10 ABOVE ZERO IN THE MID HUDSON VALLEY.
WINDS WILL BE RATHER BRISK IN THE EVENING AND WILL DECREASE
OVERNIGHT AS HIGHER PRESSURE BUILDS IN FROM THE WEST AT THE SURFACE.
WIND CHILL VALUES ARE EXPECTED TO FALL TO BELOW ZERO ACROSS THE
ENTIRE FORECAST AREA…HOWEVER THEY WILL GET DANGEROUSLY COLD
ACROSS THE SOUTHERN ADIRONDACKS AND WESTERN MOHAWK VALLEY WITH
VALUES BELOW -20 DEGREES EXPECTED HENCE THE ISSUANCE OF THE WIND
CHILL ADVISORY FOR TONIGHT INTO TUESDAY MORNING.

MODEL GUIDANCE CONTINUES TO DEVELOP A COASTAL LOW OVER THE MID
ATLANTIC REGION TONIGHT AND MOVE IT OFF THE COAST TUESDAY IN
RESPONSE TO A VIGOROUS SHORT WAVE DIGGING THE LONGWAVE TROUGH OVER
THE EASTERN UNITED STATES. HOWEVER MODEL GUIDANCE HAS TRENDED A
BIT DEEPER WITH THE LOW AND CLOSER TO THE COAST AS IT TRACKS
NORTHEASTWARD TUESDAY AFTERNOON AND NIGHT PASSING WELL SOUTH OF
LONG ISLAND. NOW ITS ASSOCIATED PRECIPITATION SHIELD IS EXPECTED
TO EXTEND NORTHWARD INTO THE REGION REACHING AREAS TO THE SOUTH
AND EAST OF THE CAPITAL DISTRICT WITH ACCUMULATING SNOWFALL. THE
GFS IS THE MOST AGGRESSIVE AND THE 06Z/NAM HAS TRENDED TOWARD THE
GFS AND BRINGS THE PRECIPITATION SHIELD INTO THE SOUTHEASTERN
MOST PORTIONS OF THE FORECAST AREA. WITH SUCH A COLD AIR IN
PLACE LIQUID TO SNOW RATIOS WOULD BE HIGH RESULTING IN LIGHT
FLUFFY SNOW WHICH WOULD EASILY BLOWN AROUND AND DRIFT.

AT THIS TIME…IT APPEARS A MODERATE SNOWFALL OF 4 TO 6 INCHES IS
POSSIBLE ACROSS LITCHFIELD AND DUTCHESS COUNTIES. HAVE HIGHLIGHTED
THIS THREAT IN OUR HAZARDOUS WEATHER OUTLOOK. AS IT THE CASE WITH
ANY COASTAL STORM A CHANGE IN ITS EXPECTED TRACK WILL HAVE AN
IMPACT ON THE EXPECTED SNOWFALL. NOTE A WINTER STORM WATCH HAS
BEEN ISSUED FOR NEW YORK CITY…LONG ISLAND AND COASTAL CT.

ONE THING THAT IS SURE IS THAT EVEN COLDER AIR WILL BE DRAWN INTO
THE REGION IN THE WAKE OF THIS LOW. TUESDAY NIGHT WILL BE THE
COLDEST NIGHT THIS WEEK AND WEDNESDAY THE COLD DAY. THE REGION
WILL BE GETTING SQUEEZED BETWEEN THE HIGH TO OUR WEST AND THE
DEPARTING LOW SO THE WINDS COMBINED WITH THE COLD TEMPERATURES WILL
RESULT IN DANGEROUS COLD WINDS CHILL TUESDAY NIGHT INTO WEDNESDAY.
LOOKS LIKE A WIND CHILL WARNING WILL LIKELY BE NEEDED FOR NORTHERN
HERKIMER AND HAMILTON COUNTIES…HAVE THIS MENTIONED IN THE
CURRENT WIND CHILL ADVISORY. AS FOR THE REST OF THE FORECAST AREA
WILL NEED WIND CHILL ADVISORIES EVEN DOWN IN THE MID HUDSON
VALLEY. HAVE THIS HIGHLIGHTED IN OUR HAZARDOUS WEATHER OUTLOOK.

STILL VERY COLD WEDNESDAY NIGHT…HOWEVER THE WINDS WILL BE MUCH
LIGHTER. THE NEED FOR ANY WIND CHILL ADVISORIES SHOULD BE LIMITED TO
THE WESTERN ADIRONDACKS WHERE TEMPERATURES WILL BE THE COLDEST.

&&

.LONG TERM /THURSDAY THROUGH SUNDAY/…
THE EXTENDED FORECAST CONTINUES TO FEATURE BELOW NORMAL…FRIGID
TEMPERATURES…AND A FEW CLIPPER TYPE LOWS IMPACTING ERN NY AND WRN
NEW ENGLAND.

ON THURSDAY…THE POLAR VORTEX CONTINUES TO DOMINATE WITH A PIECE OF
SHORT-WAVE ENERGY MOVING THROUGH THE LONGWAVE TROUGH AND PASSING
SOUTH OF MOST OF THE REGION. THE SYSTEM IS MOISTURE STARVED…BUT
MAY TAP SOME GREAT LAKES MOISTURE…AND A SLIGHT CHC OF SNOW SHOWERS
WAS PLACED IN THE FCST GRIDS SOUTH AND WEST OF THE CAPITAL
DISTRICT. H850 TEMPS WILL CONTINUE TO BE A FEW STANDARD DEVIATIONS
BELOW NORMAL…WITH THE GFS INDICATING TEMPS AT THAT LEVEL STILL IN
THE -21C TO -25C RANGE ACROSS THE FCST AREA. MAX TEMPS WILL STILL
ONLY BE IN THE TEENS ACROSS MOST OF THE REGION WITH SINGLE DIGITS IN
THE SRN DACKS…AND SRN GREEN MTNS.

THU NIGHT INTO FRIDAY…SFC HIGH PRESSURE WILL ATTEMPT TO BUILD IN
FROM THE SOUTH AND WEST. WINDS IN THE 5-10 MPH RANGE COUPLED WITH
THE VERY COLD TEMPS THU NIGHT WILL LIKELY CONTINUE WIND CHILL
HEADLINES AT LEAST FOR THE SRN DACKS REGION WHERE LOWS IN THE 10 TO
15 BELOW RANGE WILL YIELD APPARENT TEMPS IN THE 20 TO 25F BELOW
ZERO RANGE. MIN TEMPS WILL BE IN THE 5 BELOW ZERO TO 5 ABOVE ZERO
RANGE FOR MOST OF THE REST OF THE REGION…EXCEPT FOR THE MID HUDSON
RIVER VALLEY/NW CT WHERE SOME UPPER SINGLE DIGITS ARE POSSIBLE. AS
THE SFC HIGH RIDGES IN FROM THE SOUTH…SOME LOW TO MID LEVEL WARM
ADVECTION WILL OCCUR. A BRIEF LAKE CONNECTION WILL OCCUR FOR SOME
ISOLATED TO SCT SNOW SHOWERS OVER THE WRN DACKS. THE VAST MAJORITY
OF THE REGION WILL BE DRY WITH TEMPS STILL RUNNING BELOW NORMAL BY
AT LEAST 10 DEGREES WITH SINGLE DIGITS TO MID TEENS NORTH OF THE
MOHAWK VALLEY AND CAPITAL REGION…AND UPPER TEENS TO L20S TO THE
SOUTH AND EAST.

FRIDAY NIGHT INTO SATURDAY…THE NEXT CLIPPER AND ITS ASSOCIATED
COLD FRONT LOOKS TO IMPACT THE REGION. AFTER SOME MODEST WARM
ADVECTION IN THE LOW TO MID LEVELS. THE CLIPPER WILL BE APPROACHING
FROM SE CANADA AND THE GREAT LAKES REGION. THE ECMWF IS A LITTLE
FASTER THAN THE GFS WITH THIS SYSTEM BY SATURDAY MORNING. THE WEAK
ISENTROPIC LIFT AHEAD OF THE CLIPPER ITS ASSOCIATED WARM AND COLD
FRONT SHOULD ALLOW FOR A PERIOD OF LIGHT SNOW OR SNOW SHOWERS ON
SATURDAY. CHANCE POPS WERE KEPT IN DURING THE DAY. SNOW ACCUMS
COULD BE A COATING TO A FEW INCHES. AFTER LOWS IN THE SINGLE DIGITS
AND TEENS…MAX TEMPS WILL NUDGE SLIGHTLY CLOSER TO SEASONAL NORMALS
WITH U20S TO L30S IN THE VALLEYS…AND LOWER TO MID 20S OVER THE
HIGHER TERRAIN.

SATURDAY NIGHT INTO SUNDAY…THE COLD OR ARCTIC FRONT MOVES ACROSS
THE REGION WITH SUB 1000-500 HPA THICKNESSES RETURNING…AND H850
TEMPS OF -20C TO -25C ESPECIALLY FROM THE CAPITAL REGION NORTH AND
WEST. THE BIG QUESTION WILL BE IF ANOTHER CLIPPER…AS THE ECMWF
ADVERTISES IMPACTS THE REGION ON SUNDAY. THE GFS AND WPC GUIDANCE
FAVORS A FRONTAL PASSAGE IN THE MORNING WITH SOME SCT SNOW SHOWERS
AND FLURRIES. SLIGHT AND LOW CHC POPS WERE KEPT IN THE FCST FOR SAT
NIGHT INTO SUNDAY FOR THE FRONTAL PASSAGE AND THE UNCERTAINTY WITH
THIS NEXT CLIPPER POTENTIALLY APPROACHING FROM THE GREAT LAKES
REGION. TEMPS CONTINUE BELOW NORMAL WITH LOWS IN THE SINGLE DIGITS
TO LOWER TEENS FOR THE VAST MAJORITY OF THE AREA…AND HIGHS IN THE
UPPER SINGLE DIGITS TO UPPER TEENS. WIND CHILLS MAY BE AN ISSUE
AGAIN LATE IN THE WEEKEND INTO EARLY NEXT WEEK.

&&

.AVIATION /15Z MONDAY THROUGH FRIDAY/…
AN ARCTIC COLD FRONT WILL MOVE ACROSS ERN NY AND WRN NEW ENGLAND IN
THE LATE MORNING INTO THE EARLY AFTERNOON. A FRIGID AIR MASS WILL
MOVE INTO THE REGION IN ITS WAKE FOR TONIGHT.

MAINLY VFR AND HIGH MVFR CONDITIONS ARE EXPECTED THE NEXT 24 HOURS.
CIGS HAVE BEEN IN THE HIGH MVFR RANGE AT KGFL WITH SOME SNOW SHOWERS
IN THE VICINITY WITH THE BOUNDARY GETTING CLOSER TO THE CHAMPLAIN
VALLEY AND ADIRONDACKS. AS THE BOUNDARY GETS CLOSER…THE CIGS MAY
LOWER TO 2.5-3 KFT AGL AT KALB/KPSF…BTWN 15Z-18Z. VCSH GROUPS
WERE USED TO ADDRESS ISOLD-SCT SNOW SHOWERS /PERHAPS AN ISOLD
SQUALL/ WITH THE BOUNDARY. OUR CONFIDENCE WAS HIGH ENOUGH TO ADD A
TEMPO GROUP FROM 15-18Z FOR KGFL FOR MVFR CIGS/VSBYS WITH THE SNOW
SHOWERS/ISOLD SQUALLS. CONFIDENCE WAS NOT HIGH ENOUGH TO ADD THEM TO
KPSF/KALB. KPOU SHOULD STAY VFR WITH CIGS AROUND 4 KFT AGL
THROUGHOUT THE DAY. THE BOUNDARY WILL SWING THROUGH DURING THE
AFTERNOON…AND CIGS WILL RISE BACK TO VFR LEVELS…WITH CLEARING
SKIES AFTER 00Z/TUE. HOWEVER…SOME HIGH CLOUDS WILL BE ON THE
INCREASE FROM SOUTH TO NORTH AS A STORM SYSTEM ORGANIZES NEAR THE
MID ATLANTIC REGION.

THE WINDS WILL BE FROM THE SOUTH TO SOUTHWEST AT 5-12 KTS THIS
MORNING WITH SOME GUSTS CLOSE TO 20 KTS AT KALB AND KPSF…AND VEER
TO THE WEST TO NORTHWEST IN THE 18Z-21Z TIMEFRAME AT 10-18 KTS WITH
SOME GUSTS 25-30 KTS AT KPSF AND KALB. THE WINDS WILL GRADUALLY
SUBSIDE TO 8-13 KTS WITH SOME GUSTS AROUND 20 KTS AT KPSF/KALB AFTER
03Z/TUE.

OUTLOOK…
TUESDAY TO TUESDAY NIGHT TO FRIDAY: LOW OPERATIONAL IMPACT.
CHC SNOW KPOU AND KPSF.
WED-FRI: NO OPERATIONAL IMPACT. NO SIG WX.
FRIDAY NIGHT: LOW OPERATIONAL IMPACT. SLIGHT CHANCE OF SHSN.

&&

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

AN ARCTIC BOUNDARY WILL ACROSS THE REGION USHERING IN A BITTERLY
COLD AIRMASS WHICH IS EXPECTED TO REMAIN IN PLACE FOR THE REMAINDER
OF THE WEEK. THIS WILL ALLOW RIVER AND LAKE ICE TO REFORM AND
THICKEN. THE PRECIPITATION THAT OCCURS THIS WEEK WILL BE 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…NONE.
NY…WIND CHILL ADVISORY FROM 9 PM THIS EVENING TO 11 AM EST
TUESDAY FOR NYZ032-033-038-042-082.
MA…NONE.
VT…NONE.

&&

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

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