Novmerber 26, 2012 Forecast Discussion

000
FXUS61 KALY 270253
AFDALY

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ALBANY NY
950 PM EST MON NOV 26 2012

.SYNOPSIS…
A WEAK LOW PRESSURE SYSTEM WILL MOVE FROM THE CAROLINAS TO WELL
SOUTH OF LONG ISLAND BY TUESDAY AFTERNOON. SOME LIGHT SNOW WILL
OCCUR FROM THE CAPITAL REGION SOUTH…BEFORE HIGH PRESSURE BRIEFLY
BUILDS IN TUESDAY NIGHT. ANOTHER COLD FRONT WILL MOVE THROUGH THE
REGION ON WEDNESDAY WITH AN ADDITIONAL CHANCE FOR MORE SNOW
SHOWERS AND FLURRIES.

&&

.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/…
AS OF 945 PM EDT…THE CLOUDS WERE INDEED BREAKING UP ACROSS THE
CAPITAL REGION AND MOST PLACES TO THE SOUTH. LAKE EFFECT CLOUDS WERE
HANGING TOUGH TO THE NORTH. DECIDED TO GO AHEAD AND LOWER
TEMPERATURES 2-4 DEGREES FROM ALBANY SOUTHWARD WHILE LEAVING THEM
ALONE TO THE NORTH AND EAST.

LAKE EFFECT SNOW WAS NOW CONFINED MAINLY TO OUR NORTHWESTERN
AREAS…NAMELY THE ADIRONDACKS. TRIMMED BACK OUR EVENING/EARLY POPS
STILL MORE IN THESE AREAS.

HIGHER CLOUDS FROM THE DEVELOPING WAVE ACROSS THE SOUTHERN OHIO
VALLEY WERE STREAMING INTO PA AND SOON WILL BE INTO OUR REGION.
INTERESTING…A CLUSTER OF THUNDERSTORMS HAVE ERUPTED ACROSS TEXAS
AND THESE WERE RACING EAST TOWARD THE SHORTWAVE. EVEN IF THEY DON/T
CATCH UP TO THE SHORT WAVE…AN INCREASE IN HEAT AND MOISTURE FLUX
COULD STRENGTHEN THE JETSTREAM DOWNSTREAM THE CENTER…INCREASING
ASCENT.

THE 00Z NAM (BASED OFF THE 00Z UPPER AIR DATA) CONTINUE TO INDICATE
A PRETTY GOOD SHOT OF QPF TO THE SOUTH OF OUR REGION WITH A VERY
SIMILAR PICTURE ACROSS OUR REGION…LIGHT AMOUNTS SOUTH AND NOW
VIRTUALLY NO MEASURABLE QPF FROM ALBANY NORTHWARD. EVEN THE LAKE
EFFECT SNOW APPEARS TO BE MAINLY NORTH OF OUR REGION.

WITH ONLY THIS MODEL MOSTLY IN…DO NOT FEEL COMFORTABLE MAKING ANY
SIGNIFICANT CHANGES TO TOMORROW/S FORECAST. HOWEVER…THIS MODEL
WOULD PRETTY MUCH SUPPORT WHAT WE HAVE IN OUR GRIDS/ZONES/SAF
(OUTSIDE OF THE LAKE EFFECT).

FOR THE REST OF TONIGHT…LOOK FOR HIGH CLOUDS TO INCREASE…AND
TEMPERATURES BOTTOMING OUT IN THE 20S…PROBABLY A LITTLE AFTER
MIDNIGHT. THEN THEY WILL HOLD…OR EVEN RISE A POINT OR TWO AFTER
THAT.

&&

.SHORT TERM /6 AM TUESDAY MORNING THROUGH WEDNESDAY NIGHT/…
THE STORM WILL TRACK WELL SOUTH OF THE REGION AND BE TO OUR EAST
LATER ON TUESDAY. LIGHT SNOW OR SNOW SHOWERS WILL PERSIST INTO THE
AFTERNOON HOURS WELL SOUTH OF ALBANY…WHILE LIGHT SNOW SHOWERS OR
FLURRIES WILL TAKE PLACE FURTHER NORTH.

THE LATEST GUIDANCE STILL INDICATED THAT A COATING TO AT MOST (2
INCHES) MIGHT FALL WELL SOUTH AND EAST OF ALBANY…WITH THE HIGHER
AMOUNTS LIKELY ACROSS THE ELEVATED TERRAIN.

FURTHER NORTH…LITTLE OR NO SNOWFALL EXPECTED FROM ALBANY NORTHWARD
UNTIL ONE GETS INTO HAMILTON AND NORTHERN HERKIMER COUNTIES WHERE
ANOTHER DUSTING TO AROUND AN INCH OF NEW SNOW COULD ACCUMULATE.

DRIER AIR WILL OVERSPREAD THE REGION NORTHWEST TO SOUTHEAST HEADING
INTO THE AFTERNOON HOURS. THERE MIGHT EVEN BE A FEW BREAKS OF
SUNSHINE FROM ALBANY NORTHWARD DURING THE AFTERNOON.

HIGH TEMPERATURES WILL ONCE AGAIN FALL SHORT OF NORMAL…GENERALLY
IN THE MID TO UPPER 30S IN THE VALLEYS…BUT ONLY UPPER 20S TO MID
30S ACROSS THE HIGHER TERRAIN.

TUESDAY NIGHT INTO WEDNESDAY…A WEAK RIDGE OF HIGH PRESSURE WILL
BE BRIEF AS NEXT UPSTREAM SHORT WAVE APPROACHES. THIS SYSTEM DOES
HAVE RATHER STRONG FRONTOGENESIS FORCING BUT MOISTURE WILL BE
LACKING. THIS SYSTEM WILL HOWEVER TAP IN LAKE MOISTURE TO ASSIST
WITH LAKE ENHANCED SNOWFALL LATE TUESDAY NIGHT INTO WEDNESDAY. WE
WILL PLACE THE HIGHER POPS ACROSS THE DACKS AND LEAVE THE REMAINDER
OF THE CWA WITH EITHER SLIGHT CHANCE OR NO PRECIP.

HIGH PRESSURE WILL SETTLE INTO THE REGION WEDNESDAY NIGHT WITH
TRANQUIL CONDITIONS UNDER A VARIABLY CLOUDY SKY AS SOME LOW LEVEL
MOISTURE REMAINS AND AN INCREASE IN HIGHER LEVEL MOISTURE AS WARM
ADVECTION UNFOLDS UPSTREAM.

&&

.LONG TERM /THURSDAY THROUGH MONDAY/…
AT THE START OF THE LONG TERM PERIOD…FAST ZONAL FLOW ALOFT
CONTINUES TO HINDER FORECAST CONFIDENCE AS MODEL GUIDANCE STRUGGLES
TO GRASP THE LONGWAVE PATTERN. BOTH THE GFS AND ECMWF ARE IN FAIRLY
GOOD AGREEMENT WITH AN UPPER-LEVEL LOW CENTERED IN THE VICINITY OF
HUDSON BAY…WITH PIECES OF SHORTWAVE ENERGY ROTATING THROUGH IT.
MODEL GUIDANCE CONTINUES TO STRUGGLE WITH THE TIMING OF THESE
INDIVIDUAL DISTURBANCES MOVING THROUGH THE NORTHERN STREAM FLOW.
USED A BLEND OF HPC/GFS/ECMWF TO ACCOUNT FOR THESE DIFFERENCES.

WEAK HIGH PRESSURE WILL BUILD IN AT THE SURFACE FOR THURSDAY AND
FRIDAY…KEEPING THE AREA DRY. A FEW LAKE EFFECT SHOWERS MAY AFFECT
THE TUG HILL PLATEAU THURSDAY UNDER A NORTHWESTERLY ZONAL FLOW.

MODEL DIFFERENCES BEGIN TO INCREASE DURING THE WEEKEND AS PIECES OF
SHORTWAVE ENERGY WOBBLE THE NORTHERN STREAM FLOW SOUTH ACROSS THE
AREA SATURDAY. HAVE INTRODUCED SLIGHT POPS FOR THIS PERIOD
INCREASING THE POPS TO CHANCE AS A CLIPPER-TYPE LOW PRESSURE SYSTEM
APPROACHES THE REGION FROM THE NORTHWEST. HAVE KEPT FORECAST SIMPLE
WITH RAIN AND/OR SNOW…HOWEVER THERE COULD BE BRIEF PERIODS OF
MIXED PRECIPITATION AS WELL AS THE SYSTEM EXITS THE REGION DURING
THE MONDAY NIGHT-TUESDAY TIMEFRAME.

TEMPERATURES INITIALLY WILL BE BELOW NORMAL BEFORE MODERATING NEAR
THE END OF THE LONG TERM PERIOD AS THE SURFACE HIGH MOVES EAST
DURING THE WEEKEND AND SOUTHWESTERLY RETURN FLOW FILLS IN BEHIND.

&&

.AVIATION /03Z TUESDAY THROUGH SATURDAY/…
NO WEATHER RELATED PROBLEMS THROUGH ABOUT 400 AM AS ANY SNOW SHOWER
ACTIVITY SHOULD STAY TO THE WEST AND NORTH OF THE TAF SITES.

TOWARD DAYBREAK…LIGHT SNOW IS EXPECTED TO BREAK OUT ACROSS AREAS
TO THE SOUTH OF ALBANY. EVEN BEING LIGHT…WE FEEL THIS SNOW SHOULD
FAIRLY QUICKLY DROP CONDITIONS TO IFR AT KPOU AND KPSF BY THE
MORNING PEAK. FURTHER NORTH…THE SNOW LOOKS VERY LIGHT…PROBABLY
DROPPING CONDITIONS TO MVFR AT WORST AT KALB.

IFR CONDITIONS COULD LAST INTO THE AFTERNOON HOURS AT KPOU AND KPSF
BUT WILL IMPROVE WITH TIME DURING THE AFTERNOON. ANY MVFR WILL
QUICKLY GO BACK TO VFR BY AFTERNOON AT KALB.

AT KGFL…ONLY ISOLATED SNOW SHOWERS AT WORST WITH VFR EXPECTED TO
PREVAIL ALL OF TUESDAY.

THE WIND WILL BE NOT BE A PROBLEM AT THE TAF SITES…GENERALLY
STAYING BELOW 10KTS…VARIABLE TO WESTERLY.

OUTLOOK…
TUE NIGHT…VFR. NO SIG WX.
WED…VFR WITH SLIGHT SUB-VFR CHC -SHSN AT KALB/KGFL.
WED NIGHT-SAT…VFR. NO SIG WX.

&&

.HYDROLOGY…
NO HYDROLOGIC PROBLEMS ARE EXPECTED THROUGH THE NEXT 5 DAYS.

THE PREDOMINANT PTYPE WILL BE SNOW DURING THIS WEEK. THE HEAVIER
SNOW TALLIES WILL BE IN THE FAVORED LAKE SNOW BELTS /WRN DACKS
AREA/ INTO TUESDAY.

THE BELOW NORMAL TEMPS MAY ALLOW SOME ICE TO START TO FORM NORTH
OF THE MOHAWK RIVER VALLEY INTO THE ADIRONDACKS. SOME ICE EFFECTS
COULD BE SEEN ON GAGES BY LATE IN THE WEEK.

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…BGM
NEAR TERM…HWJIV/BGM
SHORT TERM…HWJIV/BGM
LONG TERM…IRL
AVIATION…HWJIV
HYDROLOGY…BGM/WASULA

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