January 19, 2012 Forecast Discussion

000
FXUS61 KALY 191126
AFDALY

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ALBANY NY
625 AM EST THU JAN 19 2012

.SYNOPSIS…
HIGH PRESSURE WILL CONTINUE TO LINGER OVER THE REGION FOR MOST OF
TODAY…THEN A FAST MOVING CLIPPER TYPE SYSTEM WILL IMPACT OUR
REGION LATE TODAY AND TONIGHT…BRINGING SOME LIGHT SNOW AND SNOW
SHOWERS TO OUR REGION. A MORE SIGNIFICANT STORM MAY IMPACT OUR
REGION LATE FRIDAY NIGHT THROUGH SATURDAY AS IT MOVES FROM THE
TENNESSEE VALLEY ACROSS THE MIDDLE ATLANTIC REGION.

&&

.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/…
AS OF 600 AM…PREVIOUS FORECAST IN GOOD SHAPE. HAV EONLY MADE SOME
MINOR ADJUSTMENTS TO THE HOURLY TEMP GRIDS. DID NOT RECREATE ANY
WORDED PRODUCTS SINCE CHANGES MADE WOULD NOT AFFECT THESE PRODUCTS.

PREVIOUS DISCUSSION
WILL START OUT THE DAY WITH MAINLY CLEAR SKIES…THEN CLOUDS WILL
RAPIDLY INCREASE THIS AFTERNOON AHEAD OF A FAST MOVING UPPER LEVEL
TROF AND COLD FRONTAL BOUNDARY. TOWARD SUNSET…SNOW SHOWERS WILL
HAVE ALREADY BEGUN TO SPREAD ACROSS THE WESTERN PART OF THE FORECAST
AREA. HIGHS TODAY WILL BE IN THE 20S AND LOWER 30S…WITH SOUTHERLY
WINDS INCREASING TO 10 TO 15 MPH…WITH GUSTS TO 25 MPH POSSIBLE
IN SOME AREAS.

SNOW SHOWERS WILL RAPIDLY OVERSPREAD THE REGION THIS EVENING FROM
WEST TO EAST AS THE TROF AND FRONT MOVE RAPIDLY EAST. HAVE FORECAST
LIKELY TO CATEGORICAL POPS THIS EVENING UNTIL A LITTLE AFTER
MIDNIGHT. AFTER MIDNIGHT…EXPECT THAT THE SNOW SHOWERS WILL HAVE
TAPPERED OFF IN MOST PLACES…EXCEPT FOR AREAS EAST OF LAKE ONTARIO
WHERE LAKE ENAHNACEMENT WILL KEEP SNOW SHOWERS GOING THROUGH THE
NIGHT. LOWS THURSDAY NIGHT WILL GENERALLY BE IN THE TEENS AND LOWER
20S. EXPECT ABOUT A HALF INCH TO TWO INCHES OF SNOW ACROSS MOST
AREAS…WITH UP TO AROUND 3 INCHES ACROSS THE ADIRONDACK PART OF THE
FORECAST AREA.

&&

.SHORT TERM /FRIDAY THROUGH SATURDAY/…
A BRIEF VISIT BY HIGH PRESSURE ON FRIDAY…THEN ANOTHER FAST MOVING
SYSTEM WILL AFFECT THE REGION LATE FRIDAY NIGHT AND SATURDAY. THIS
LOW PRESSURE SYSTEM WILL BE BETTER ORGANIZED AND ALSO TRACK TO THE
SOUTH OF THE REGION…MOVING OFF THE MID ATLANTIC COAST ON SATURDAY.
HEAVIER SNOW POSSIBLE WITH THIS SYSTEM…BUT NO MAJOR STORM IS
EXPECTED. PRELIMINARY FORECAST SNOWFALL AMOUNTS INDICATE ONE TO FOUR
INCHES OF SNOW POSSIBLE ACROSS THE NORTHERN HALF OF THE FORECAST
AREA…AND 3 TO 7 INCHES OVER THE SOUTH. HOWEVER…WOULD NOT TAKE
MUCH OF A SOUTHWARD SHIFT IN THE TRACK OF THIS LOW PRESSURE SYSTEM
TO REDUCE THESE SNOWFALL AMOUNTS SIGNFICANTLY.

SOME MODEL DIFFERENCES EXIST IN TERMS OF TIMING OF THIS EVENT.
GFS/ECMWF HAVE SIMILAR TIMING WITH THE SNOW STARTING AROUND OR
SHORTLY AFTER MIDNIGHT FRIDAY NIGHT…AND ENDING BY EARLY AFTERNOON
SATURDAY. THEN NAM STARTS THE SNOW AROUND SUNRISE ON SATURDAY…AND
LINGERS IT INTO EARLY SATURDAY EVENING. FOR NOW HAVE FORECAST CLOSER
TO THE FASTER GFS/ECMWF SOLUTIONS. DESPITE THE TIMING DIFFERENCES…
MODEL FORECASTS OF SNOWFALL AMOUNTS ARE SIMILAR.

STILL COLD THIS PERIOD…HIGHS FRIDAY WILL BE IN THE UPPER TEENS TO
LOWER 30S…LOWS FRIDAY NIGHT IN THE SINGLE NUMBERS AND TEENS…
HIGHS SATURDAY IN THE 20S.

&&

.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/…
FAST BROAD CYCLONIC FLOW WITH EMBEDDED UPPER IMPULSES WILL CONTINUE
TO AFFECT OUR REGION THROUGH THE PERIOD…WITH A RELATIVELY STRONG
SYSTEM TO AFFECT THE REGION BETWEEN SUNDAY NIGHT AND MONDAY
EVENING. FIRST…SATURDAY NIGHT AND SUNDAY…HIGH PRESSURE WILL
CONTROL THE WEATHER WITH LOWS IN THE TEENS…SINGLE NUMBERS IN THE
SOUTHERN ADIRONDACKS. HIGHS SUNDAY WITH INCREASING CLOUDS IN THE LOW
TO MID 30S…WITH UPPER 20S IN HIGHER ELEVATIONS.

STRONG UPPER ENERGY APPROACHES SUNDAY NIGHT…WITH INCREASING WARM
ADVECTION AND ISENTROPIC LIFT…AND AREAS OF PRECIPITATION WILL
SPREAD ACROSS THE REGION. LOTS OF UNCERTAINTY ON THE TIMING OF WARM
AIR ALOFT BUT THE GENERAL CONSENSUS FOR SNOW CHANGING TO MIXED
PRECIPITATION VERY LATE SUNDAY NIGHT AND THROUGH MONDAY MORNING.
MIXED PRECIPITATION WOULD INCLUDE SOME POSSIBILITIES FOR FREEZING
RAIN. BY MONDAY AFTERNOON…MOST AREAS OUTSIDE OF THE SOUTHERN
ADIRONDACKS SHOULD SEE A COLD RAIN…WITH SOME MIXED PRECIPITATION
POSSIBLY ALL DAY IN THE SOUTHERN ADIRONDACKS. LOWS SUNDAY NIGHT IN
THE MID 20S TO NEAR 30…SOME TEENS IN THE SOUTHERN ADIRONDACKS.
HIGHS MONDAY IN THE UPPER 30S TO MID 40S…FEW COOLER AREAS IN THE
SOUTHERN ADIRONDACKS.

CONSIDERABLE SPREAD IN GUIDANCE/ENSEMBLES BEYOND MONDAY NIGHT.
SYSTEM MOVES OUT SOME TIME WITHIN THE TIME WINDOW BETWEEN MONDAY
AFTERNOON AND TUESDAY MORNING…WITH COLD ADVECTION BEGINNING.
PRECIPITATION TRANSITIONS TO SNOW SHOWER ACTIVITY. LOWS MONDAY
NIGHT IN THE 20S TO LOWER 30S. DRYING AND CLEARING EITHER LATE
MONDAY NIGHT OR TUESDAY…AND REMAINING DRY THROUGH WEDNESDAY. HIGHS
TUESDAY IN THE 30S TO LOWER 40S. SOME STRONGER COLD ADVECTION
WEDNESDAY WITH HIGHS IN THE MID 30S TO NEAR 40…SOME 20S IN HIGHER
ELEVATIONS.

&&

.AVIATION /12Z THURSDAY THROUGH MONDAY/…
— Changed Discussion —
HIGH PRESSURE IS CONTROLLING THE WEATHER THROUGH THIS AFTERNOON
WITH VFR CONDITIONS. THE NEXT SYSTEM WILL AFFECT OUR REGION THIS
EVENING…AND INDICATING MVFR VISIBILITIES AND CEILILNGS WITH LIGHT
SNOW AFTER 03Z AT KGFL AND KALB. MOST OF THE SNOW CHANCES ARE NORTH
OF KPOU…BUT ACKNOWLEDGING A VCSH THERE. SNOW CHANCES SHOULD END
BEFORE SUNRISE AND A RETURN TO VFR CONDITIONS IS INDICATED AFTER 09Z.

LIGHT WINDS WILL BECOME SOUTH TO SOUTHWEST AT LESS THAN 10 KT TODAY
AND CONTINUE THIS EVENING. WINDS WILL SHIFT TO WEST AND NORTHWEST
AROUND 09Z AND INCREASE TOWARD 10 KT.

OUTLOOK…
FRI…VFR. NO SIG WX.
SAT…MVFR/IFR. SNOW LIKELY.
SUN…VFR. NO SIG WX.
MON…VFR/MVFR/IFR. CHC -RA/-SN.
— End Changed Discussion —

&&

.HYDROLOGY…
NO MAJOR PROBLEMS ARE EXPECTED ON THE MAIN STEM RIVERS THROUGH THE
WEEKEND AS ANY PRECIPITATION WHICH FALLS WILL BE IN THE FORM OF SNOW.

COLD AND DRY WEATHER WILL PREVAIL THROUGH MOST OF TODAY…FOLLOWED
BY A CLIPPER TYPE SYSTEM WHICH IS EXPECTED TO BRING LIGHT SNOW TO
THE REGION LATE TODAY AND TONIGHT. A MORE SIGNIFICANT STORM IS
EXPECTED TO TRACK FROM THE TENNESSEE VALLEY TOWARD THE MIDDLE
ATLANTIC COAST BRINGING A GENERALLY LIGHT TO MODERATE SNOWFALL TO
THE REGION LATE FRIDAY NIGHT INTO SATURDAY WITH THE POTENTIAL FOR
HEAVIER SNOW ACROSS THE HIGHER TERRAIN SOUTH AND EAST OF CAPITAL
DISTRICT.

ICE FORMATION ON BODIES OF WATER IS EXPECTED TO INCREASE AGAIN
THROUGH THE END OF THE WEEK AS COLD AIR WILL BE IN PLACE ACROSS
THE REGION.

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…GJM
NEAR TERM…GJM
SHORT TERM…GJM
LONG TERM…NAS
AVIATION…NAS
HYDROLOGY…GJM

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