063 FXUS61 KALY 100257 AFDALY AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE ALBANY NY 957 PM EST SUN JAN 9 2011 .SYNOPSIS... HIGH PRESSURE WILL BUILD INTO ONTARIO AND THE GREAT LAKES REGION THROUGH TUESDAY...BEFORE ANOTHER POSSIBLE COASTAL STORM IMPACTS THE REGION WITH SNOW TUESDAY NIGHT AND WEDNESDAY. && .NEAR TERM /UNTIL 6 AM MONDAY MORNING/... AS OF 950 PM EST...CLOUDS AND SNOW SHOWERS/FLURRIES PERSIST ACROSS THE DACKS...AND HIGHER ELEVATIONS ACROSS THE SCHOHARIE VALLEY/EASTERN CATSKILLS...AND ACROSS HIGHER ELEVATIONS OF SOUTHERN VT/WESTERN MA. IN VALLEYS...CLOUDS HAVE INCREASED FROM ALBANY NORTH...WITH CLEAR TO PARTLY CLOUDY SKIES FURTHER S. A RATHER POTENT SHORTWAVE WAS NOTED ON WV SATELLITE IMAGERY...OVER EAST CENTRAL QUEBEC AND HEADING S. THIS FEATURE SHOULD PASS FROM N TO S ACROSS THE REGION TOWARD...OR AROUND DAYBREAK. AS IT APPROACHES...SOME INCREASING SYNOPTIC LIFT...IN COMBINATION WITH SOME LAKE MOISTURE...AND RESIDUAL MID LEVEL MOISTURE FROM THE ATLANTIC SHOULD COMBINE TO INCREASE THE AREAL COVERAGE OF SNOW SHOWERS AND FLURRIES ACROSS CENTRAL AND NORTHERN PORTIONS OF THE REGION. IN FACT...SOME ADDITIONAL LIGHT ACCUMS ARE EXPECTED ACROSS THE WESTERN DACKS...ABOUT 1-3 INCHES...AND ALSO HIGHER WEST FACING TERRAIN IN SOUTHERN VT...WHERE 1-2 INCHES WILL BE POSSIBLE...ALONG WITH ISOLATED HIGHER AMOUNTS...AND PERHAPS UP TO AN INCH ACROSS THE SCHOHARIE VALLEY...WESTERN MOHAWK VALLEY...AND BERKSHIRES. ACROSS VALLEY AREAS...SOME FLURRIES SHOULD REDEVELOP FROM ALBANY NORTH. SO...HAVE BOOSTED POPS SLIGHTLY IN AFOREMENTIONED HIGHER ELEVATIONS...ESP ACROSS THE WESTERN DACKS. AND...WITHIN VALLEYS FROM THE CAPITAL REGION NORTH...HAVE ADDED MENTION OF SCATTERED FLURRIES...WITH PERHAPS A FEW DUSTINGS OCCURRING THROUGH DAYBREAK. AS FOR TEMPS...HAVE KEPT MINS THE SAME...BUT SLOWED DOWN THE OVERALL TEMP CURVE OVERNIGHT...AS CLOUDS AND WIND SHOULD KEEP TEMPERATURES FROM FALLING MUCH THROUGH MIDNIGHT...BEFORE FALLING MORE RAPIDLY RIGHT AROUND DAYBREAK WHEN SOME BREAKS IN THE CLOUDS MAY DEVELOP AS SUBSIDENCE DEVELOPS WITH THE PASSAGE OF THE AFOREMENTIONED SHORTWAVE. OTHERWISE...JUST SOME MINOR TWEAKS TO HOURLY TEMPS/DEWPOINTS/WINDS ACCORDING TO RECENT OBS. PREVIOUS DISCUSSION FOLLOWS... ANOTHER TRICKY FORECAST TONIGHT...LIKE LAST NIGHT...AS AREAS THAT SEE PERIODS OF CLEARING SHOULD SEE COLDER LOWS THAN AREAS THAT SEE MORE CLOUDS. GRANTED...BOUNDARY LAYER FLOW IS STRONG...AND WILL MIX TO SOME DEGREE TO THE SURFACE...BUT SOME VALLEY AREAS...SUCH AS AROUND GFL AND POU...CAN SEE VERY LIGHT WINDS WHEN BOUNDARY LAYER FLOW IS WEST OR NORTHWEST. SOME MOISTURE BACKING SOUTH AND WEST OUT OF NORTHERN NY...COULD RESULT IN A COUPLE OF INCHES OF SNOW IN PARTS OF THE SOUTHERN ADIRONDACKS. THE NORTHWEST FLOW SHOULD AIM LAKE EFFECT MOISTURE MAINLY INTO THE WESTERN MOHAWK VALLEY AND SCHOHARIE VALLEY AS LITTLE MULTIBANDS...SO LOCALIZED INCH OR TWO POSSIBLE THERE OVERNIGHT. LOWS GENERALLY IN THE TEENS...WITH SOME SINGLE NUMBERS IN THE ADIRONDACKS...AND NORTHERN LAKE GEORGE SARATOGA REGION. && .SHORT TERM /6 AM MONDAY MORNING THROUGH WEDNESDAY/... LINGERING NORTHWEST FLOW AND LAKE EFFECT MULTIBAND SNOW SHOWER ACTIVITY COULD ADD LIGHT ACCUMULATIONS IN THE WESTERN MOHAWK VALLEY...SCHOHARIE VALLEY AND SOUTHERN ADIRONDACKS THROUGH MONDAY MORNING. PERIODS OF CLOUDS AND SUN MOST AREAS MONDAY...WITH BREEZY CONDITIONS EARLY...AND EASING WINDS THROUGH THE AFTERNOON. HIGHS MONDAY IN THE 20S TO AROUND 30. WEAK HIGH PRESSURE BUILDS IN MONDAY NIGHT THROUGH TUESDAY...WITH LIGHT WINDS...AND GRADUALLY DECREASING CLOUD COVER. LOWS MONDAY NIGHT...WITH LIGHTER WINDS...MORE CLEARING...AND SNOW PACK...AROUND 10 TO LOWER TEENS...AROUND 0 SOUTHERN ADIRONDACKS...LAKE GEORGE AND SARATOGA REGION. HIGHS TUESDAY...WITH INCREASING HIGH CLOUDS AHEAD OF THE NEXT SYSTEM...IN THE 20S TO LOWER 30S. SOME LIGHT SNOW COULD WORK ITS WAY INTO THE NORTHEASTERN CATSKILLS BY LATE TUESDAY AFTERNOON. THE NEXT SYSTEM...LOOKS TO BE A PHASING OF THE CURRENT GULF COAST SYSTEM...AND NORTHERN STREAM ENERGY CURRENTLY AROUND THE NORTHERN ROCKIES. SOURCES OF GUIDANCE AND ENSEMBLES IN UNUSUALLY GOOD AGREEMENT ON THE PREDICTED LARGE SCALE EVOLUTION OF THE SYSTEM. GULF COAST SYSTEM QUITE DYNAMIC NOW...BUT GUIDANCE CONSENSUS SUGGESTS DEAMPLIFICATION AND WEAKENING AS IT TRACKS TOWARD THE COASTAL CAROLINAS. HOWEVER...THE ATMOSPHERIC DEEP MOISTURE AND POTENTIAL VORTICITY FOOTPRINT WILL STILL EXIST...LIKE A FUSE THAT JUST NEEDS TO BE RE-LIT. THE LOW LEVEL FEATURE IS PREDICTED TO EMERGE OFF THE CAROLINAS...WITH THE GULF STREAM AND THERMAL GRADIENT BAROCLINICITY LIGHTING THE FUSE. THE NORTHERN STREAM UPPER ENERGY AND DYNAMICS COULD SUPPORT SOME ENSUING CONVECTIVE FIREWORKS AND THE SNOW BOMBS BURSTING IN AIR AS THE STORM DEVELOPS OFF THE CAROLINAS AND MID ATLANTIC COAST. O.K. THAT MIGHT HAVE BEEN TOO POETIC...BUT SOME HINTS AT CONVECTIVE CHARACTER TO SYSTEM WITH SOME DOWNSTREAM UPPER RIDGING...THAT COULD STEER THE SYSTEM ALONG THE MORE NORTHWESTERN PREDICTED TRACKS IN GUIDANCE. WIND ANOMALIES AT 850 HPA SUGGEST BETTER THAN AVERAGE MOISTURE CONVERGENCE AND ADVECION OFF ATLANTIC...BUT CLOSED UPPER LOW DOES LOOK PROGRESSIVE...NOT AN UPPER CUT OFF...EVIDENT IN 250 HPA WIND ANOMALIES. HOWEVER...BOUNDARY LAYER FRONTOGENESIS IMPRESSIVE...AND BEST UPWARD VERTICAL MOTION SHOULD CUT THROUGH THE DENDRITIC -12C TO -18C GROWTH ZONE IN A RELATIVELY DECENT LAYER OF THE ATMOSPHERE. MESOSCALE BANDING WILL HAVE TO BE MONITORED...AS IT IS TOO EARLY TO BE SPECIFIC ON WHERE ENHANCED SNOWFALL RATES OF >2"+ PER HOUR COULD SET UP. BIGGEST SNOWS COULD BE SOUTHERN NY INTO SOUTHERN AND CENTRAL/EASTERN NEW ENGLAND...OR COULD SHIFT A BIT WEST TOWARD THE BERKSHIRES...EASTERN NY AND SOUTHERN VT...WE JUST HAVE TO WAIT AND SEE. SO...ABOVE AVERAGE CONFIDENCE IN A SNOWSTORM WITH SIGNIFICANT IMPACTS...BUT FOR NOW...UNTIL THE EVENT GETS CLOSER...THE BIGGEST IMPACTS LOOK TO BE SOMEWHERE AROUND OR EAST OF THE NY AND NEW ENGLAND BORDER AND SOUTH OF VT...PERHAPS POU THROUGH LITCHFIELD COUNTY CT...MAYBE TO PSF...WITH THE UNDERSTANDING SOME ADJUSTMENTS IN ANY DIRECTION ARE POSSIBLE AS THE EVENT GETS NEARER. AREAS OF CENTRAL AND EASTERN NEW YORK...INCLUDING THE HUDSON VALLEY...CAPITAL DISTRICT...THROUGH THE WESTERN MOHAWK VALLEY...SOUTHERN ADIRONDACKS...SCHOHARIE VALLEY AND NORTHEASTERN CATSKILLS SHOULD SEE AT LEAST LIGHT TO LOCALLY MODERATE SNOWS AS THE NORTHERN STREAM UPPER ENERGY TRANSFERS TO THE STRENGTHENING OFFSHORE SYSTEM. AGAIN...A SLIGHT NORTHWEST SHIFT TO THE TRACK OF THE SYSTEM...AND HEAVIER SNOWS WOULD BE POSSIBLE IN THE HUDSON VALLEY AND CAPITAL DISTRICT TO SOUTHERN VT...STAY TUNED. LOWS TUESDAY NIGHT AROUND 20 TO THE MID 20S...SOME TEENS IN THE SOUTHERN ADIRONDACKS THROUGH SOUTHERN VT. HIGHS WEDNESDAY IN THE 20S TO LOWER 30S. && .LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/... THE PERIOD STARTS OUT WITH THE NOR'EASTER HEADING OUT TO SEA. THERE COULD STILL BE SOME LINGERING WRAP-AROUND LIGHT SNOW SHOWERS WEDNESDAY NIGHT...ESPECIALLY ACROSS THE FAVORED HIGHER TERRAIN LOCATIONS. OTHERWISE...A FLAT RIDGE ALOFT WILL SET UP ACROSS MUCH OF THE GREAT LAKES INTO THE NORTHEAST...BUT WITH SOME LAKE EFFECT SNOW SHOWERS POSSIBLE ACROSS AREAS WEST OF THE HUDSON VALLEY WITH A N-NW FLOW THURSDAY INTO THURSDAY NIGHT. LAKE EFFECT ACTIVITY WILL TEND TO DIMINISH ON FRIDAY AS THE FLOW TURNS DECIDEDLY ANTICYCLONIC WITH A SURFACE RIDGE OF HIGH PRESSURE BUILDING IN FROM THE OHIO VALLEY. TRANQUIL CONDITIONS WITH SEASONABLE TEMPS SHOULD THEN PERSIST THROUGH FRIDAY NIGHT AS THE RIDGE MOVES OVERHEAD. HOWEVER...WITH FAST ZONAL FLOW ALOFT DEVELOPING...A SURFACE TROF AND ASSOCIATED PROGRESSIVE UPPER LEVEL TROF AXIS IS FORECAST TO MOVE THROUGH IN THE LATE SATURDAY THROUGH SUNDAY MORNING TIME FRAME. DUE TO TIMING DIFFERENCES IN MODEL FORECASTS...WILL MENTION LOW CHANCE POPS ACROSS THE ENTIRE AREA. WITH THE TRACK OF THE MAIN CYCLONE PASSING BY WELL NORTH OF THE AREA AND A DE-AMPLIFIED UPPER PATTERN...EXPECTING JUST SNOW SHOWERS WITH LIGHT ACCUMULATIONS WITH THIS SYSTEM. DRIER AIR SHOULD THEN FILTER IN FOR SUNDAY. && .AVIATION /03Z MONDAY THROUGH FRIDAY/... AS OF 950 PM EST...HAVE ADDED MENTION OF LOW LEVEL WIND SHEAR FOR KGFL...WHERE SFC WINDS HAVE DROPPED BELOW 10 KT...AND WINDS AROUND AND ABOVE 2000 FT AGL REMAIN FROM THE NW AT 30-40 KT...AS DEPICTED IN KALY 00Z SOUNDING. PREVIOUS DISCUSSION FOLLOWS... STRONG LOW PRESSURE MOVING INTO THE CANADIAN MARITIMES WILL MAINTAIN A BRISK NORTHWEST FLOW ACROSS THE TAF SITES THROUGH 00Z/TUE. THERE WILL BE OCCASIONAL CLOUDS...MAINLY WITHIN VFR RANGE...AND MOST NUMEROUS AT KALB AND KGFL OVERNIGHT INTO MON MORNING. SOME FLURRIES MAY REDEVELOP LATER TONIGHT...ESP AT KALB...AS A WEAK UPPER LEVEL DISTURBANCE PASSES ACROSS THE REGION TOWARD OR AFTER DAYBREAK...AND COMBINES WITH A BIT OF LAKE MOISTURE. AT THIS TIME...DO NOT ANTICIPATE REDUCTIONS IN VSBY...BUT RADAR TRENDS WILL NEED TO BE WATCHED LATER TONIGHT IN CASE ANY BETTER DEFINED LAKE ENHANCED SNOWBAND OR SNOW SHOWERS APPROACH KALB. FOR MONDAY...AFTER ANY CLOUDS/FLURRIES...EXPECT VFR CONDITIONS WITH SCT-BKN CLOUD BASES BETWEEN 3500-5000 FT AGL. WINDS WILL REMAIN FROM THE NW TO WNW THROUGH 00Z/TUE...WITH SPEEDS OF 10-15 KT AT KALB...AND GENERALLY LESS THAN 8 KT AT KGFL AND KPOU. SOME GUSTS OF 20-25 KT WILL REMAIN POSSIBLE AT KALB. FOR MONDAY...SPEEDS WILL INCREASE TO 10-15 KT...WITH OCCASIONAL GUSTS REACHING 25-30 KT AT KALB. WINDS SHOULD GRADUALLY SUBSIDE AFTER 22Z/MON. OUTLOOK... MON NT-TUE...VFR. NO SIG WX. TUE NGT-WED...MVFR/IFR...-SN/SN LIKELY WITH CHC +SN. THU-FRI...VFR. NO SIG WX. && .HYDROLOGY... TEMPERATURES ARE EXPECTED TO REMAIN BELOW FREEZING THROUGH MOST OF NEXT WEEK. ICE WILL CONTINUE TO THICKEN ON MAIN STEM RIVERS OVER THE NEXT SEVERAL DAYS ALTHOUGH SNOW COVER ON TOP OF THE ICE MAY SLOW THE RATE OF INCREASE IN ICE THICKNESS. OUTSIDE OF SOME UPSLOPE SNOW SHOWERS...THE NEXT CHANCE OF PRECIPITATION LOOKS TO BE LATE TUESDAY INTO WEDNESDAY BUT ONCE AGAIN THIS PRECIPITATION LOOKS TO 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...NONE. MA...NONE. VT...NONE. && $$ SYNOPSIS...NAS NEAR TERM...KL/NAS SHORT TERM...NAS LONG TERM...JPV AVIATION...KL/JPV HYDROLOGY...NAS/JPV