February 5, 2014 Forecast Discussion

000
FXUS61 KALY 052108
AFDALY

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ALBANY NY
408 PM EST WED FEB 5 2014

.SYNOPSIS…
LOW PRESSURE WILL CONTINUE TO TRACK NORTHEASTWARD INTO THE CANADIAN
MARITIMES…ALLOWING FOR SNOW TO END ACROSS OUR REGION THIS EVENING.
A RIDGE OF HIGH PRESSURE WILL THEN GRADUALLY BUILD EASTWARD INTO THE
OHIO VALLEY AND MID ATLANTIC REGION THROUGH EARLY SATURDAY. BELOW
NORMAL TEMPERATURES AND MAINLY DRY CONDITIONS ARE EXPECTED…EXCEPT
FOR SOME LAKE EFFECT SNOW SHOWERS OVER THE WESTERN ADIRONDACKS.

&&

.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/…
AS OF 400 PM EST…WINTER STORM WARNING CONTINUES THROUGH 6 PM FOR
THE ENTIRE AREA.

PLEASE SEE OUR PUBLIC INFORMATION STATEMENT FOR THE LATEST SNOWFALL
TOTALS. ALBANY HAS BROKEN THE SNOWFALL RECORD FOR THIS DATE WITH 8.5
INCHES AS OF 4 PM…WHICH BROKE THE OLD RECORD OF 8.1 SET BACK IN
2001.

SNOW HAS LIGHTENED CONSIDERABLY LATE THIS AFTERNOON FROM AROUND THE
CAPITAL REGION SOUTHWARD…WHILE A SWATH OF MODERATE SNOW CONTINUES
FOR AREAS TO THE NORTH FROM AROUND THE MOHAWK VALLEY AND SARATOGA
REGION NORTHWARD. THIS SECONDARY AREA OF SNOW IS BEING FORCED BY
DEFORMATION AHEAD OF AN UPPER LEVEL TROUGH OVER THE EASTERN GREAT
LAKES…WITH A DISTURBANCE ROUNDING THE BASE OF THE TROUGH INTO
SOUTH-CENTRAL NY AND PA. THIS COLD CONVEYOR-BELT SNOW WILL CONTINUE
INTO THE EARLY EVENING…AS THERE ARE STILL DECENT RADAR RETURNS
LAGGING BACK TO CENTRAL NY. SO WILL MENTION THE HIGHEST POPS FOR
THESE AREAS…BUT ALSO INTERMITTENT LIGHT SNOW WILL STILL BE
POSSIBLE ACROSS SOUTHERN AREAS AS IT IS NOT BEING DETECTED WELL BY
RADAR DUE TO BEING MORE SHALLOW. LITTLE ADDITIONAL ACCUMULATION IS
EXPECTED FROM AROUND THE CAPITAL REGION SOUTHWARD…WITH STILL A FEW
MORE INCHES LIKELY FOR AREAS TO THE NORTH.

LATER THIS EVENING…THE SNOW SHOULD TAPER TO FLURRIES AS THE SYSTEM
RAPIDLY PULLS AWAY. EXPECTING SOME BREAKS IN THE CLOUDS AFTER
MIDNIGHT…WITH A COLD ADVECTION REGIME RESULTING IN TEMPERATURES
DROPPING INTO THE SINGLE DIGITS TO AROUND 10…WITH BELOW ZERO
READINGS IN THE ADIRONDACKS.

&&

.SHORT TERM /6 AM THURSDAY MORNING THROUGH FRIDAY NIGHT/…
IN WAKE OF THE STORM…WE WILL LEFT WITH A WESTERLY ZONAL FLOW ALOFT
THROUGH THE PERIOD HIGH PRESSURE BUILDING JUST TO OUR SOUTH. THIS
PATTERN SHOULD RESULT IN MAINLY DRY CONDITIONS FOR MUCH OF THE AREA.
HOWEVER…WITH THE WESTERLY FLOW AND SLIGHTLY ANOMALOUSLY COLD AIR
AT 850MB ALONG WITH LAKE ONTARIO WATER TEMPERATURES IN THE UPPER
30S…SOME LAKE EFFECT SNOW SHOWERS SHOULD BE ABLE TO EXTEND INTO
THE WESTERN ADIRONDACKS ONCE THE WINDS ALIGN FROM THURSDAY NIGHT
THROUGH FRIDAY NIGHT. A MITIGATING FACTOR TO THE STRENGTH OF LAKE
EFFECT BANDS ARE LOW CAPPING INVERSION HEIGHTS OF ONLY 1 TO 1.5 KM
DURING THIS TIME…WHICH SHOULD LIMIT ACCUMULATIONS TO MINOR AMOUNTS.

TEMPERATURES ARE EXPECTED TO BE BELOW NORMAL THURSDAY AND
FRIDAY…WITH SIMILAR READINGS OF LOWER TO MID 20S IN VALLEY
LOCATIONS AND TEENS IN THE HIGHER TERRAIN. NIGHT-TIME LOWS WILL
GENERALLY BE IN THE SINGLE DIGITS BELOW ZERO TO SINGLE DIGITS ABOVE
ZERO.

&&

.LONG TERM /SATURDAY THROUGH WEDNESDAY/…
THERE CONTINUES TO REMAIN UNCERTAINTY REGARDING CHANCES FOR
ACCUMULATING SNOWFALL LATE SUNDAY INTO MONDAY…WITH HIGH PRESSURE
DOMINATING THE REST OF THE LONG TERM PERIOD.

AT THE START OF THE LONG TERM PERIOD…HIGH PRESSURE WILL BE IN
PLACE ACROSS THE REGION RESULTING IN MAINLY DRY CONDITIONS FOR THE
FORECAST AREA WITH PARTLY CLOUDY SKIES. THERE MAY BE A FEW LIGHT
LAKE EFFECT SNOW SHOWERS ACROSS PORTIONS OF THE SOUTHERN ADIRONDACKS
AND HAVE INDICATED SLIGHT CHANCE POPS ACROSS THESE AREAS.

THIS AREA OF HIGH PRESSURE WILL DEPART TO THE EAST SATURDAY
NIGHT…USHERING IN A PERIOD OF UNSETTLED WEATHER TO END THE WEEKEND
AND BEGIN NEXT WEEK. WITH FRESH SETS OF UPPER AIR DATA BEING
INGESTED INTO THE MODELS…LONG RANGE GUIDANCE HAS STARTED TO COME
INTO BETTER AGREEMENT HANDLING THE EVOLUTION OF PACIFIC ENERGY
MOVING ONSHORE THE WESTERN CONUS AND LATER EJECTING OUT OF THE
ROCKIES. GUIDANCE IS NOW INDICATING A SOUTHERN STREAM DOMINATED
SYSTEM…THAT WILL ALLOW FOR COASTAL DEVELOPMENT OFF THE SOUTHEAST
CONUS…BUT A TRACK THAT WILL EVENTUALLY LEAD THE LOW PRESSURE
SYSTEM OUT TO SEA.

HOWEVER…A PIECE OF NORTHERN STREAM ENERGY SUPPORTED BY A 120+ KT
JET STREAK AND PV ANOMALY WILL HELP CARVE OUT AN UPPER-LEVEL TROUGH
THAT WILL MOVE ACROSS THE GREAT LAKES DURING THE DAY SUNDAY…AND
ACROSS OUR REGION SUNDAY NIGHT INTO MONDAY. UNLIKE PRIOR
RUNS…THERE IS A GROWING CONSENSUS THAT THERE WILL BE LITTLE IF ANY
COASTAL DEVELOPMENT ASSOCIATED WITH THIS UPPER TROUGH…RESULTING IN
A PERIOD OF LIGHT SNOW DRIVEN LARGELY BY UPPER-LEVEL JET DYNAMICS
AND DIFFERENTIAL VORTICITY ADVECTION AS NORTHERN STREAM INFLUENCES
DOMINATE. ENOUGH GULF MOISTURE SHOULD BE PUMPED NORTHWARD IN THE
LOW-LEVEL SOUTHWESTERLY FLOW AHEAD OF THE UPPER TROUGH TO ALLOW FOR
A COUPLE OF INCHES TO FALL ACROSS THE REGION. WILL NOT MENTION THIS
SYSTEM IN THE HWO AT THIS TIME AS THERE CONTINUES TO REMAIN
UNCERTAINTY REGARDING THE EVOLUTION OF THE UPPER-LEVEL TROUGH AND
WHETHER ANY WEAK SURFACE CYCLOGENESIS ALONG THE COAST ACCOMPANIES
IT…WHICH COULD BUMP SNOWFALL TOTALS A LITTLE HIGHER.

THIS UPPER-LEVEL TROUGH WILL QUICKLY EXIT OFF TO THE NORTHEAST
MONDAY NIGHT…BEING REPLACED BY A LARGE AREA OF HIGH PRESSURE THAT
WILL RESULT IN DRY WEATHER FOR THE MIDDLE OF NEXT WEEK. LONG RANGE
GUIDANCE DOES HINT AT ANOTHER SYSTEM TAKING SHAPE ACROSS THE
MID-TENNESSEE VALLEY…BUT TOO FAR OUT IN TIME TO KNOW EXACTLY WHAT
WILL HAPPEN WITH THIS SYSTEM.

HIGH TEMPERATURES THROUGHOUT THE LONG TERM PERIOD WILL GENERALLY
RANGE FROM THE MID TEENS TO UPPER 20S. LOW TEMPERATURES WILL
GENERALLY RANGE FROM SLIGHTLY BELOW ZERO ACROSS THE HIGHER TERRAIN
OF THE SOUTHERN ADIRONDACKS TO THE LOW TEENS ACROSS THE MID-HUDSON
VALLEY WITH SINGLE DIGITS ACROSS THE REST OF THE REGION.

&&

.AVIATION /21Z WEDNESDAY THROUGH MONDAY/…
MAJOR WINTER STORM CONTINUES TO IMPACT THE REGION. THE PRIMARY LOW
OVER WESTERN PENNSYLVANIA IS WEAKENING AS THE SECONDARY COASTAL LOW
DEEPENS OFF THE NEW JERSEY COAST. IN ADDITION…THE UPPER LEVEL
TROUGH ASSOCIATED WITH THE STORM IS APPROACHING FROM THE GREAT LAKES
REGION.

THE COASTAL LOW WILL BECOME THE PRIMARY LOW AS WE HEAD THROUGH THE
AFTERNOON AND EVENING HOURS AS IT MOVES NORTHEASTWARD AND OUT TO
SEA. THE UPPER TROUGH WILL SWING THIS EVENING. SOME WARMER AIR HAS
WORKED IN ALOFT INTO THE MID HUDSON VALLEY AND LITCHFIELD COUNTY
RESULTING IN SOME SLEET AND FREEZING RAIN. THIS THREAT WILL END AS
THE COASTAL LOW HEAD OFFSHORE. OTHERWISE…SNOW WILL CONTINUES
ACROSS THE AREA WITH MORE OF A FOCUS ACROSS THE NORTHERN PORTION OF
THE FORECAST AREA IN ASSOCIATION WITH THE UPPER TROUGH. EXPECTING
THE SNOW TO TAPER OFF LATER THIS AFTERNOON AND INTO THE EVENING
ACROSS THE AREA. IFR-MVFR CONDITIONS IMPROVING TO MVFR AS THE SNOW
LIGHTENS UP AND ENDS. VFR CONDITIONS ARE EXPECTED TO RETURN FOR THE
OVERNIGHT HOURS.

NORTHEAST TO NORTH WINDS WILL SHIFT TO THE NORTH AND WEST AS THE
COASTAL LOW MOVES OFFSHORE THIS EVENING. NORTHWEST WINDS ARE
EXPECTED OVERNIGHT INTO THURSDAY AFTERNOON.

OUTLOOK…
THU NIGHT-SAT: NO OPERATIONAL IMPACT. NO SIG WX.
SAT NIGHT-SUN: MODERATE OPERATIONAL IMPACT. CHANCE OF SN.

&&

.HYDROLOGY…
NO WIDESPREAD HYDRO PROBLEMS ARE EXPECTED THROUGH THE NEXT FIVE
DAYS. THE CURRENT SNOWSTORM WILL CONTINUE TO WIND DOWN THIS
EVENING…WITH MAINLY DRY CONDITIONS EXPECTED THROUGH THE REST OF
THE WORK WEEK EXCEPT FOR SOME LAKE EFFECT SNOW SHOWERS OVER THE
WESTERN ADIRONDACKS.

THERE IS A CHANCE FOR SNOW THIS WEEKEND…WITH CURRENT INDICATIONS
THAT ACCUMULATIONS WILL BE ON THE LIGHT SIDE.

WITH TEMPERATURES EXPECTED TO BE BELOW NORMAL FOR THE NEXT SEVERAL
DAYS…ICE WILL THICKEN ON BODIES OF WATER.

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…WINTER STORM WARNING UNTIL 6 PM EST THIS EVENING FOR CTZ001-
013.
NY…WINTER STORM WARNING UNTIL 6 PM EST THIS EVENING FOR NYZ032-
033-038>043-047>054-058>061-063>066-082>084.
MA…WINTER STORM WARNING UNTIL 6 PM EST THIS EVENING FOR MAZ001-
025.
VT…WINTER STORM WARNING UNTIL 6 PM EST THIS EVENING FOR
VTZ013>015.

&&

$$
SYNOPSIS…JPV
NEAR TERM…JPV
SHORT TERM…JPV
LONG TERM…IRL
AVIATION…IAA
HYDROLOGY…JPV

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