November 13, 2014 Forecast Discussion

000
FXUS61 KALY 140217
AFDALY

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ALBANY NY
917 PM EST THU NOV 13 2014

.SYNOPSIS…
FIRST MEASURABLE SNOWFALL FOR MUCH OF THE FORECAST AREA EXPECTED
TONIGHT WITH ACCUMULATIONS MAINLY ON GRASSY SURFACES. SNOW IS
EXPECTED TO COME TO AN END BEFORE THE MORNING COMMUTE. IN THE
MEANTIME…LAKE ENHANCED SNOW WILL CONTINUE INTO THE WESTERN
ADIRONDACKS. A REINFORCING SHOT OF COLD AIR WILL TAKE HOLD FRIDAY
AND LAST INTO THE WEEKEND.

&&

.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/…
AS OF 915 PM…A BAND OF STEADY LIGHT SNOW IS PROGRESSING EASTWARD
ACROSS THE MOHAWK VALLEY AND PARTS OF THE SARTAOGA REGION. IR
SATELLITE IMAGERY HAS SHOW A STEADY DECREASE IN CLOUD TOP
TEMPERATURES WHICH IS CAUSING THIS LIGHT SNOW BAND TO DEVELOP.
THIS WILL MAKES ITS WAY THROUGH THE IMMEDIATE CAPITAL REGION IN
THE NEXT COUPLE OF HOURS. PLEASE USE EXTRA CAUTION IF TRAVELING ON
ROADWAYS IN THE NEXT FEW HOURS WHERE LOCALIZED SLIPPERY CONDITIONS
ARE POSSIBLE. WITH THE ASSIST OF THE UPTON NEW YORK RADAR…THERE
IS ALSO A SECOND AREA OF PRECIPITATION ACROSS DUTCHESS AND
LITCHFIELD COUNTIES. CURRENT OBSERVATIONS IN OUR EXTREME SOUTHERN
AREAS ARE STILL SHOWING RAIN SHOWERS ACROSS THE REGION BUT THIS
WILL EVENTUALLY CHANGE TO SNOW.

LATEST LOCAL HRRR MODEL AND RAP MODEL RUN UPDATES HAVE BEEN CONSISTENT
WITH SLIGHTLY MORE QPF ACROSS THE SOUTHERN REGIONS WHERE SNOWFALL
TOTALS HAVE BEEN INCREASED SLIGHTLY IN THE HIGHEST TERRAIN ACROSS THE
SOUTHERN BERKSHIRES INTO THE NORTHERN LITCHFIELD HILLS WILL RANGE
BETWEEN ONE TO TWO INCHES WITH ISOLATED AREAS UP TO THREE INCHES
POSSIBLE BY EARLY FRIDAY MORNING.

PREV DISC…
SHORT WAVE IS MOVING ACROSS THE GREAT LAKES REGION INTO THE OHIO
VALLEY THROUGH THE LONGWAVE TROUGH. THIS PIECE OF ENERGY IS INDUCING
THE DEVELOPMENT OF A LOW OFF THE MID ATLANTIC COAST. GUIDANCE IS
WELL CLUSTERED MOVING THE SURFACE LOW NORTHEASTWARD PASSING IT JUST
TO THE SOUTH AND EAST OF CAPE COD AROUND 12Z/FRIDAY. THESE FEATURES
WILL BRING A LIGHT SNOWFALL TO THE REGION TONIGHT…MAINLY THIS
EVENING. REGIONAL RADARS ARE BLOSSOMING TO THE WEST. INITIALLY THE
PRECIPITATION SHOULD START OUT A RAIN AND SNOW IN THE VALLEY WITH
ALL SNOW EXPECTED BY 9-10PM. THE SNOW IS EXPECTED TO END BEFORE THE
MORNING COMMUTE…BY AROUND 07Z ACROSS OUR WESTERN NEW ENGLAND
COUNTIES. GENERALLY LOOKING AT LESS THAN AN INCH BELOW 1000 FEET
WITH 1 TO 2 INCHES ABOVE 1000 FEET AND FOR LITCHFIELD COUNTY.

LAKE ENHANCED SNOW WILL CONTINUE INTO THE WESTERN ADIRONDACKS
TONIGHT AS THE SOUTHWESTERLY FLOW CONTINUES AHEAD OF APPROACHING
TROUGH.

TEMPERATURES ARE EXPECTED TO DROPPED INTO MAINLY THE 20S OVERNIGHT.

&&

.SHORT TERM /6 AM FRIDAY MORNING THROUGH SATURDAY NIGHT/…
FLOW ACROSS REGION WILL SHIFT TO THE NORTHWEST AS THE LOW MOVES
NORTHEAST AWAY FROM THE REGION. ALOFT THE UPPER TROUGH AXIS WILL
SWING THROUGH MAINLY DURING THE MORNING AND CYCLONIC WILL SET UP
ACROSS THE REGION. COLDER AIR MASS WILL BLANKET REGION WITH 850 MB
TEMPERATURES DROPPING TO -10 TO -12 DEGREES CELSIUS ACROSS THE
FORECAST AREA. WITH THIS COLD AIR MOVING ACROSS THE GREAT LAKES
LAKE EFFECT CLOUDS AND SHOWERS IMPACTING PORTIONS OF THE FORECAST
AREA…MAINLY THE WESTERN MOHAWK VALLEY INTO THE EASTERN CATSKILLS.
THE LAKE EFFECT WILL DIMINISH SATURDAY AND SHOULD COME TO AN END
BY SATURDAY NIGHT AS RIDGING BUILDS IN. THE RIDGE`S VISIT WILL BE
BRIEF AS IT MOVES QUICKLY OFFSHORE SATURDAY NIGHT AHEAD OF THE
NEXT SYSTEM.

COLD WITH TEMPERATURES RUNNING 10 TO 15 DEGREES BELOW NORMAL.

&&

.LONG TERM /SUNDAY THROUGH THURSDAY/…
A VERY ACTIVE AND CHILLY PATTERN SETTING UP FOR THE LONG TERM PERIOD
AS A VIGOROUS UPPER TROUGH /POLAR VORTEX/ DIVES SOUTHWARD AND
EASTWARD OF THE CONTINENTAL DIVIDE.

MONDAY…PLENTY OF MODEL DISCREPANCIES REMAIN AS THE ECMWF REMAINS
ON THE WARMER SIDE OF THE GUIDANCE ENVELOPE WITH THE GGEM/GFS ON THE
COLDER SIDE. IN ADDITION…THE GGEM IS STRONGER WITH THE COASTAL
WAVE REFLECTION AS OPPOSED TO THE FLATTER AND FASTER WAVE OF THE GFS
WITH THE ECMWF SOMEWHAT IN THE MIDDLE. AT THIS TIME…AND PER
COLLABORATION WITH WPC…WE WILL LEAN TOWARD THE MORE STABLE ECMWF.
THIS WOULD RESULT THE CHANCE FOR ACCUMULATING SNOW FOR THE HIGHER
TERRAIN NORTH AND WEST OF ALBANY WITH MAINLY RAIN /PERHAPS A LITTLE
SNOW MIX/ SOUTH AND EAST OF ALBANY. FOR NOW…WE WILL HAVE HIGH
CHANCE POPS UNDER A CLOUDY SKY. WPC GUIDANCE TEMPS ARE A GREAT
COMPROMISE WITH LEANING TOWARD A SLIGHTLY COLDER SOLUTION DUE TO WET
BULB PROCESS.

MONDAY NIGHT THROUGH WEDNESDAY…WHAT WAVE DOES DEVELOP WILL QUICKLY
TRACK TO THE NORTHEAST MONDAY EVENING. COLD AIR ADVECTION AND DEEP
CYCLONIC FLOW WILL RESULT IN LAKE EFFECT ACTIVITY DEVELOPING
DOWNWIND OF LAKE ONTARIO WHICH WILL BE THE MAIN WEATHER STORY FOR
THE REMAINDER OF THE LONG TERM PERIOD. OTHERWISE…BELOW NORMAL
TEMPERATURES AS H850 TEMPS ARE AT OR BELOW -10C AND MAINLY CLOUD
COVERAGE INTO THE TERRAIN WITH UPSLOPE CONDITIONS. MORE CLEARING
WILL TAKE PLACE DOWNWIND OF THE TERRAIN…ESPECIALLY IN THE MID
HUDSON VALLEY.

&&

.AVIATION /02Z FRIDAY THROUGH TUESDAY/…
PERIOD OF LIGHT WINTRY MIXTURE CHANGING TO MAINLY SNOW TONIGHT FOR
TAF SITES. THE INITIAL VFR CONDITIONS WILL GRADUALLY DETERIORATE TO
MVFR LATER THIS EVENING. THERE COULD BE A PERIOD OF IFR CONDITIONS
AT KPOU AS BANDED PRECIP MAY LIMIT BOTH VIS AND CIGS.
OVERNIGHT…THE COASTAL SYSTEM WILL RAPIDLY PULL AWAY AS IMPROVING
CONDITIONS WILL OCCUR WITH RESPECT TO DIMINISHING SNOW AND IMPROVING
VISIBILITIES. HOWEVER…CIGS WILL REMAIN AT OR WITH MVFR RANGE THE
REMAINDER OF THE NIGHT.

DURING FRIDAY…WEST-NORTHWEST WINDS WILL INCREASE WHICH WILL ASSIST
WITH CIGS BREAKING UP TO VFR CONDITIONS. HOWEVER…UPSLOPE
CONDITIONS FOR KPSF MAY HOLD ONTO THE BKN CIGS A BIT LONGER.

OUTLOOK…
FRI NIGHT: LOW OPERATIONAL IMPACT. SLIGHT CHANCE OF SHSN.
SAT-SAT NIGHT: NO OPERATIONAL IMPACT. NO SIG WX.
SUN: LOW OPERATIONAL IMPACT. SLIGHT CHANCE OF SHRA…SHSN.
SUN NIGHT: MODERATE OPERATIONAL IMPACT. CHANCE OF SHRA…SHSN.
MON: HIGH OPERATIONAL IMPACT. LIKELY RA…SN.
MON NIGHT: LOW OPERATIONAL IMPACT. SLIGHT CHANCE OF SHSN.
TUESDAY: NO OPERATIONAL IMPACT. NO SIG WX.

&&

.HYDROLOGY…
NO HYDROLOGIC PROBLEMS ARE EXPECTED INTO EARLY NEXT WEEK.

MAINLY LIGHT AND FROZEN PRECIPITATION INTO THE WEEKEND. A STORM
SYSTEM WILL IMPACT THE REGION TO END THE WEEKEND AND START THE NEW
WORK WEEK. THERE IS MUCH UNCERTAINTY WITH THE SYSTEM…REFER TO THE
LONG TERM DISCUSSION FOR DETAILS.

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…NONE.
MA…NONE.
VT…NONE.

&&

$$
SYNOPSIS…IAA
NEAR TERM…LFM
SHORT TERM…IAA
LONG TERM…BGM
AVIATION…ELH
HYDROLOGY…IAA

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