December 11, 2013 Forecast Discussion

000
FXUS61 KALY 112141
AFDALY

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ALBANY NY
440 PM EST WED DEC 11 2013

.SYNOPSIS…
A BRISK WESTERLY FLOW WILL BRING SIGNIFICANT LAKE EFFECT SNOWFALL TO
PORTIONS OF THE SOUTHERN ADIRONDACKS THROUGH TONIGHT. AN ARCTIC COLD
FRONT CROSSING THE REGION WILL BRING A FEW SNOW SHOWERS
TONIGHT…AND FOLLOWED BY SLIGHTLY COLDER AIR FOR THURSDAY. YET
ANOTHER CLIPPER AND COLD FRONT WILL BRING A FEW MORE SNOW SHOWERS
LATE THURSDAY NIGHT INTO FRIDAY. ADDITIONAL LAKE EFFECT SNOWFALL
WILL OCCUR THURSDAY INTO FRIDAY AS WELL.

&&

.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/…
AS OF 430 PM EDT…ALL HEADLINES REMAIN IN EFFECT. KTYX RADAR
INDICATED A STRENGTHENING LAKE BAND OFF LAKE ONTARIO REACHING INTO
NORTHERN HERKIMER COUNTY…LIKELY PRODUCING 2 OR MORE INCHES PER
HOUR UNDERNEATH THE BAND.

ALSO STILL OBSERVING A MUCH NARROW BAND THAT HAS NEVERTHELESS LINED
UP NEAR THE I-90 CORRIDOR WITH SNOWFALL RATES OF AN INCH OR MORE
LIKELY THAT SHOULD WEAKENED IN THE NEXT COUPLE OF HOURS. A SPECIAL
WEATHER STATEMENT HAS BEEN ISSUED WITH THAT BAND…AS IT MOVES OVER
THE NORTHWAY…COULD CAUSE LOCALIZED WHITEOUTS AND SLICK ROADS AND A
QUICK INCH OF SNOW.

A LAKE EFFECT SNOW WARNING REMAINS IN EFFECT FOR NORTHERN HERKIMER
AND HAMILTON COUNTIES THROUGH 6AM EST THURSDAY. IN ADDITION…A LAKE
EFFECT SNOW ADVISORY REMAINS IN EFFECT FOR NORTHERN WARREN
COUNTY…SPECIFICALLY THE PORTION BORDERING HAMILTON COUNTY ACROSS
THE HIGHER TERRAIN…THROUGH MIDNIGHT TONIGHT.

THROUGH THE EVENING DRIVE…LOOK FOR IT TO REMAIN BRISK WITH A
WESTERLY WIND 5 TO 15 MPH. MOST PLACES WILL BE DRY WITH NOTHING MORE
THAN A FEW FLURRIES (OUTSIDE THE AFOREMENTIONED SNOW BANDS).
TEMPERATURES WILL BE 25-30 IN THE VALLEYS…TEENS TO LOWER 20S
HIGHER ELEVATIONS. TEMPERATURES WILL BEGIN TO FALL BY THE END OF THE
EVENING DRIVE.

THIS EVENING…THE LAKE EFFECT SNOWBAND OFF OF LAKE ONTARIO WILL
CONTINUE TO IMPACT NORTHERN HERKIMER COUNTY WORKING INTO HAMILTON
AND EVEN WARREN COUNTIES. WE HAVE ADMITTEDLY NOT RECEIVED ANY
REPORTS OF SIGNIFICANT SNOW IN WARREN COUNTY. HOWEVER…WE SUSPECT
SOME SNOW HAS FALLEN. THE CSTAR FUNDED KVIE PROGRAM INDICATE A GOOD
INLAND EXTENT OF WELL OVER 100 MILES OF A SINGLE BAND FROM LAKE
ONTARIO. THE SURFACE TO 10,000 FOOT WIND FLOW LINES UP AROUND A 270
VECTOR AND SLANTWISE INSTABILITY IS MODERATE TO EXTREME. THE CAPPING
INVERSION STARTS TO NEAR 10,000 FEET TONIGHT WHICH ALLOWS FOR CLOUD
TOP NEARLY THAT HIGH. TEMPERATURES ARE PLENTY COLD ENOUGH THROUGH
THE LAYER FOR OPTIMAL DENDRITIC GROWTH. SO FAR…HAVE NOT SEEN ANY
CLOUD TO GROUND LIGHTNING STRIKES WHICH WOULD INDICATE CLOUD TOPS
OVER 10,000 FEET AND EVEN POTENTIALLY HEAVIER SNOW RATES. PERHAPS A
LITTLE DRY AIR ENTRAINMENT IS THE ONLY INHIBITING FACTOR TO AN
OTHERWISE EPIC LAKE EVENT SNOWFALL.

THE BAND OF LAKE ERIE SHOULD FALL APART AS THE SUBSIDENCE LOWERS IN
THIS AREA AND THE FLOW EVENTUALLY VEERS TO A MORE NORTHWEST VECTOR.
ALSO THE FLOW WEAKENS A LITTLE.

LATER TONIGHT…A WEAK REINFORCING COLD FRONT WILL WORK THROUGH WITH
VERY LITTLE MOISTURE OF ITS OWN…AND IT WILL EVENTUALLY DISRUPT THE
NORTHERN BAND OF LAKE ONTARIO. EVENTUALLY THIS BAND WILL BECOME MORE
FRAGMENTED AND SLIP SOUTH THROUGH THE MOHAWK VALLEY…POSSIBLY
CLIPPING THE CAPITAL DISTRICT AND AREAS TO THE EAST WHERE UPSLOPE
ENHANCEMENT COULD BRING A QUICK INCH OR SO OF SNOW TO THE CENTRAL
TACONICS AND BERKSHIRES. IN THE CAPITAL DISTRICT…ANY LOCALIZED
ACCUMULATIONS WILL BE A DUSTING TO UNDER AN INCH.

MOST OF THE REGION WILL REMAIN DRY WITH NOTHING MORE THAN A FEW
PATCHY CLOUDS AND FLURRIES ALTHOUGH THE AFOREMENTIONED FRONTAL BOUNDARY
COULD BRING A LOCALIZED BRIEF SNOW SQUALL OR TWO ON ITS OWN. IT WILL
BE COLD…A LITTLE COLDER THAN LAST NIGHT WITH LOWS GENERALLY IN THE
TEENS FROM ALBANY SOUTHWARD…SINGLE NUMBERS TO AROUND ZERO FURTHER
NORTH.

A WEST TO SOUTHWEST WIND WILL TURN TO THE NORTHWEST WITH
TIME…GENERALLY 5 TO 15 MPH WITH A FEW HIGHER GUSTS.

&&

.SHORT TERM /6 AM THURSDAY MORNING THROUGH FRIDAY NIGHT/…
FOR THURSDAY INTO THURSDAY NIGHT…ALTHOUGH THE MAIN LAKE EFFECT
POTENTIAL WILL SHIFT SOUTH AND WEST OF THE REGION THURSDAY
MORNING…LAKE EFFECT SNOW BANDS COULD SHIFT BACK NORTH IN THE
AFTERNOON AND AT NIGHT AS THE LOW LEVEL FLOW BACKS AHEAD OF YET
ANOTHER INCOMING CLIPPER. LOW LEVEL INSTABILITY STILL LOOKS RATHER
IMPRESSIVE ACROSS MOST OF THE REGION THURSDAY AS THE MID LEVEL COLD
POOL MOVES ACROSS…SO AT LEAST SCATTERED SNOW SHOWERS…AND PERHAPS
A FEW EMBEDDED HEAVIER SQUALLS COULD OCCUR…MAINLY NORTH AND WEST
OF THE CAPITAL DISTRICT…WITH ADDITIONAL MINOR SNOWFALL
ACCUMULATIONS POSSIBLE. AS FOR THE LAKE EFFECT POTENTIAL…MODERATE
ADDITIONAL ACCUMULATIONS COULD OCCUR ACROSS PORTIONS OF THE WESTERN
MOHAWK VALLEY AND ADIRONDACKS…SO NEW LAKE EFFECT SNOW ADVISORIES
AND OR WARNINGS MIGHT BE NEEDED.

TEMPERATURES WILL REMAIN WELL BELOW AVERAGE…WITH MAX TEMPS ONLY
REACHING THE SINGLE DIGITS AND TEENS FOR HIGHER ELEVATIONS…AND
GENERALLY LOWER TO MID 20S ACROSS VALLEY AREAS. THU NT/FRI AM MINS
SHOULD FALL INTO THE SINGLE DIGITS NORTH AND WEST OF THE CAPITAL
DISTRICT….TEENS CAPITAL DISTRICT SOUTH.

BY FRIDAY AND FRIDAY NIGHT…ANOTHER CLIPPER WILL WORK NORTH OF THE
REGION…DRAGGING YET ANOTHER ARCTIC FRONT ACROSS THE REGION. THERE
ARE SOME TIMING DIFFERENCE WITH THE NAM MODELS BRINGING IT THROUGH
ON FRIDAY AND THE GFS FRIDAY NIGHT. EITHER WAY…IT REMAINS COLD.
THE FRONT COULD TRIGGER ADDITIONAL SNOW SQUALLS ON ITS OWN.

LAKE EFFECT OVER THE ADIRONDACKS LOOKS TO TRANSITION MORE INTO AN
UPSLOPE EVENT WITH SNOW SHOWERS CONTINUING THROUGH MUCH OF FRIDAY.
EVENTUALLY BY FRIDAY…THE FLOW WILL GO MORE NORTHERLY WHICH COULD
TAP SOME MOISTURE OFF LAKE CHAMPLAIN AND DEVELOP A LAKE EFFECT PLUME
SOUTH INTO WASHINGTON COUNTY…PERHAPS CLIPPER SOUTHWESTERN VERMONT
AND THE BERKSHIRES AS WELL. USUALLY THESE DO NOT BRING MORE THAN A
COUPLE INCHES OF LOCALIZED SNOWFALL.

MEANWHILE…LAKE ENHANCED SNOW SHOWERS WILL LIKELY SHIFT SOUTH FROM
THE ADIRONDACKS INTO THE CENTRAL MOHAWK VALLEY AND EVENTUALLY
NORTHERN CATSKILLS. AMOUNTS HERE LOOK LIGHT BUT IN A FEW SPOTS COULD
BE LOCALLY MODERATE.

THE REMAINDER OF THE AREA AGAIN COULD SEE A FEW SNOW SHOWERS OR
LOCALIZED SNOW SQUALLS CAPABLE OF COATING THE GROUND IN A HURRY.

THE FRONT LOOKS TO STALL SOMEWHERE JUST SOUTH OF THE REGION FRIDAY
NIGHT. LOW LEVEL CONVERGENCE…COMBINED WITH INCREASED MID LEVEL
FRONTOGENETICAL FORCING SHOULD LEAD FLURRIES OR VERY LIGHT SNOW NEAR
AND IN THE WAKE OF THE BOUNDARY AND NORTH OF IT BY FRIDAY NIGHT.
MOISTURE IS INITIALLY LACKING SO FOR NOW…BUT WILL CONTINUE A 30
POP FOR LIGHT SNOW FROM ALBANY SOUTHWARD…SLIGHT CHANCES FURTHER
NORTH.

THIS WILL NEED TO BE WATCHED FOR POSSIBLE MINOR ACCUMULATIONS OF SNOW.
AS FOR LAKE EFFECT SNOW…SOME MAY BE ONGOING ACROSS THE WESTERN
ADIRONDACKS FRI AM. HOWEVER…A LOWERING INVERSION LEVELS…AND
VEERING WINDS WITH THE FRONTAL PASSAGE SHOULD SQUELCH LAKE EFFECT BY
LATE FRI.

CONTINUED VERY COLD FRIDAY WITH HIGHS ONLY REACHING THE TEENS
NORTH…20S TO NEAR 30 SOUTH. LOWS FRIDAY NIGHT WILL DIP AROUND ZERO
IN OUR NORTHWESTERN AREAS…TO 10-15 IN THE CAPITAL REGION…15-20
SOUTH. THIS ASSUMES WE WILL HAVE PLENTY OF CLOUD COVER. IF THE
CLOUDS WERE TO THIN…ESPECIALLY NORTH…IT COULD BE EVEN COLDER.

&&

.LONG TERM /SATURDAY THROUGH WEDNESDAY/…
…POTENTIALLY SIGNIFICANT WINTER STORM IMPACT THIS WEEKEND…

THERE IS STILL A GOOD CONSENSUS FROM DETERMINISTIC AND ENSEMBLE
GUIDANCE FOR A STORM TO TRACK OFF THE LONG ISLAND AND NEW ENGLAND
COAST OVER THE WEEKEND. THE ORIGINS OF THE SYSTEM ARE STILL OVER
THE PACIFIC…RESULTING IN LOTS OF UNCERTAINTY IN THE FORECASTED
TRACK AND POTENTIAL IMPACT TO THE REGION. THE EXACT TRACK WILL
DETERMINE HOW FAR NORTH THE HEAVIER PRECIPITATION GETS. THERE IS A
GOOD CONSENSUS THAT THERE WILL BE A PERIOD OF ENHANCED ISENTROPIC
LIFT AND FRONTOGENESIS ASSOCIATED WITH WARM ADVECTION SATURDAY
THROUGH SATURDAY NIGHT…PERHAPS LINGERING INTO SUNDAY MORNING. SOME
HEADLINES MAY BE NECESSARY DUE TO POTENTIAL SNOW AMOUNTS…SINCE
MOST AREAS SHOULD BE COLD ENOUGH FOR SNOW. THERE COULD BE A ZONE OF
MIXED PRECIPITATION IN SOUTHERN AREAS…BUT AGAIN WITH UNCERTAINTIES
IN THE STORM TRACK…JUST GOING WITH SNOW FOR NOW…WHICH WILL
PROBABLY NEED TO BE ADJUSTED AS WE GET CLOSER.

ONCE THE SYSTEM EXITS…LAKE EFFECT SNOW BANDS SHOULD DEVELOP…AND
ACKNOWLEDGING CHANCES FOR SNOW SHOWERS SUNDAY AFTERNOON THROUGH
WEDNESDAY FOR AREAS BORDERING THE SOUTHERN ADIRONDACKS AND EASTERN
CATSKILLS. HIGH TEMPERATURES SATURDAY THROUGH WEDNESDAY SHOULD BE
BELOW FREEZING…BUT AROUND FREEZING DURING THE WEEKEND STORM IN
SOUTHERN AREAS. LOWS SHOULD BE BELOW NORMAL THROUGH THE PERIOD AND
PERHAPS GET DOWN TO THE SINGLE NUMBERS IN MANY PLACES MONDAY
NIGHT…WITH SOME BELOW ZERO READINGS IN SOME AREAS.

SO…THERE ARE STILL SIGNIFICANT UNCERTAINTIES AS TO THE STORM TRACK
WITH THE MOST LIKELY SCENARIO AT THIS TIME BEING SOME ACCUMULATING
SNOW FOR MANY AREAS OVER THE WEEKEND. THERE ARE STILL CHANCES THAT
THE STORM COULD TRACK SO FAR SOUTH THAT WE SEE LITTLE TO NO
SNOW…OR IT COULD TRACK CLOSER TO US AND BRING MIXED PRECIPITATION
FURTHER NORTH. THESE DETAILS WILL GET SORTED OUT AS WE GET CLOSER

&&

.AVIATION /21Z WEDNESDAY THROUGH MONDAY/…
EVEN THOUGH ISOLATED TO SCT SNOW SHOWERS/SQUALLS COULD PRODUCE IFR
CONDITIONS THIS EVENING AS A SECONDARY ARCTIC FRONT MOVES THROUGH…
THE PROBABILITY OF IFR CONDITIONS AT ANY OF THE TAF SITES LOW SO
HAVE NOT INCLUDED ANY IFR CONDITIONS IN THE KALB/KGFL/KPOU/KPSF TAF
SITES FOR THIS TAF PERIOD. HAVE FORECAST VCSH THROUGH ABOUT 08Z/09Z
WITH MAINLY VFR CIGS. THE EXCEPTION IS MVFR CIGS ARE FORECAST AT
KPSF AFTER 00Z. AFTER 09Z THE CLOUD COVER WILL BECOME MAINLY SCT AT
THE TAF SITES FOR A TIME…THEN BECOME BKN AGAIN AFTER AROUND 15Z.

SURFACE WINDS WILL BE WESTERLY AT 10 TO 15 KTS WITH GUSTS OF 20 TO
25 KTS INTO THIS EVENING…THEN DECREASE TO MAINLY 10 KTS OR LESS
THIS EVENING AND CONTINUE THAT WAY THROUGH EARLY THURSDAY.

OUTLOOK…
THURSDAY AFTERNOON AND NIGHT: LOW OPERATIONAL IMPACT. SLIGHT CHANCE
OF SHSN.
FRIDAY: MODERATE OPERATIONAL IMPACT.BREEZY CHANCE OF SHSN.
FRIDAY NIGHT: MODERATE OPERATIONAL IMPACT. CHANCE OF SHSN.
SATURDAY: MODERATE OPERATIONAL IMPACT. LIKELY SN.
SATURDAY NIGHT: HIGH OPERATIONAL IMPACT. DEFINITE SN.
SUNDAY: HIGH OPERATIONAL IMPACT. DEFINITE SN.

&&

.HYDROLOGY…
NO HYDRO RELATED CONCERNS ARE EXPECTED THIS WEEK. THE PRECIPITATION
THAT OCCURS WILL BE IN THE FORM OF SNOW…EXCEPT A WINTRY MIX IS
POSSIBLE OVER THE WEEKEND FOR SOUTHERN AREAS.

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…LAKE EFFECT SNOW ADVISORY UNTIL MIDNIGHT EST TONIGHT FOR
NYZ042.
LAKE EFFECT SNOW WARNING UNTIL 6 AM EST THURSDAY FOR NYZ032-
033.
MA…NONE.
VT…NONE.

&&

$$
SYNOPSIS…HWJIV/KL
NEAR TERM…HWJIV
SHORT TERM…HWJIV/KL
LONG TERM…NAS
AVIATION…GJM
HYDROLOGY…IAA/HWJIV/KL

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