February 24, 2012 Forecast Discussion

000
FXUS61 KALY 240245
AFDALY

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ALBANY NY
945 PM EST THU FEB 23 2012

.SYNOPSIS…
A WEAK RIDGE OF HIGH PRESSURE WILL SLIDE ACROSS THE REGION EARLY
TONIGHT. A COMPLEX LOW PRESSURE SYSTEM WILL THEN AFFECT THE REGION
LATE TONIGHT INTO FRIDAY NIGHT WITH ADDITIONAL SNOW AND RAIN. SOME
LINGERING SNOW SHOWERS ALONG WITH WINDY CONDITIONS WILL OCCUR IN
THE WAKE OF THE STORM ON SATURDAY. FAIR AND CHILLY CONDITIONS WILL
RETURN FOR SUNDAY.

&&

.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/…
AS OF 945 PM EST…TEMPERATURES RANGED FROM THE MID TO UPPER 20S
NORTHWEST TO THE MID TO UPPER 30S SOUTHEAST WITH MOSTLY CLOUDY TO
CLOUDY SKIES AS EVEN THOUGH LOWER LEVEL CLOUDS ERODED THIS EVENING
HIGH CLOUDS HAVE OVERSPREAD THE FA. EXPECT A SLOW DROP IN TEMPS
FOR THE REMAINDER OF THIS EVEN WITH A SLOW RISE IN THE DEWPOINTS.
DOUBLE BARREL LOW PRESSURE CENTER WAS QUICKLY MOVING EAST
NORTHEAST FROM ERN KY AND SRN IN. FOR THE REMAINDER OF THE EVEN
EXPECT MID LEVEL CLOUDS TO QUICKLY INCREASE WITH DRY CONDITIONS
REMAINING THROUGH MIDNIGHT.

AFTER MIDNIGHT…HAVE SLOWED THE ONSET OF PCPN BY AN HOUR OR
TWO…WHILE STILL EXPECTING A BAND OF PRECIP TO BLOSSOM FROM SW
TO NE ACROSS THE SOUTHERN HALF OF THE REGION IN RESPONSE TO
APPROACHING TROUGH AND INTENSIFYING MID LEVEL FRONTOGENESIS…IT
WILL TAKE A LITTLE LONGER TO SATURATE THE LOWER LEVELS. THERMAL
PROFILES STILL SUGGEST ENOUGH DEEP DRY AIR EXISTS THAT SUFFICIENT
WET BULB COOLING SHOULD ALLOW P-TYPE TO BEGIN AS SNOW. GIVEN THE
INTENSITY OF F-GEN AND ISENTROPIC LIFT…AND THE POTENTIAL FOR
SOME ELEVATED INSTABILITY JUST S/W OF THE REGION…PRECIP
INTENSITY MAY BEGIN QUITE STRONG…AS A BRIEF BURST OF MOD-HVY
SNOW IN MOST AREAS BTWN 07Z AND 11Z. BOUNDARY LAYER TEMPS IN THE
MID HUDSON VALLEY AND SOUTHERN LITCHFIELD CO MAY BE INITIALLY WARM
ENOUGH TO LIMIT SNOW ACCUMS TO AN INCH OR LESS. HOWEVER…SHOULD
PRECIP LINGER LONGER THAN EXPECTED…HIGHER ACCUMS COULD OCCUR IN
A SHORT DURATION.

TOWARD DAYBREAK…THIS DEVELOPING BAND OF MOD-HVY PRECIP SHOULD
CONTINUE EXPANDING NE…REACHING THE CAPITAL REGION…SCHOHARIE
VALLEY AND BERKSHIRES. THIS SHOULD PRODUCE A QUICK 1-2 INCHES OF
SNOWFALL BY DAYBREAK IN THIS REGION…WITH LESS THAN AN INCH
FURTHER N AND E.

THE PRECIP MAY CHANGE TO SLEET/FREEZING RAIN ACROSS HIGHER
ELEVATIONS OF THE CATSKILLS/SCHOHARIE VALLEY BY DAYBREAK…AND
PLAIN RAIN IN THE MID HUDSON VALLEY/SOUTHERN LITCHFIELD CO REGION.
ELSEWHERE…EXPECT P-TYPE TO BE MAINLY SNOW…POSSIBLY MODERATE TO
HEAVY IN INTENSITY IN SOME AREAS FURTHER N CLOSE TO…OR JUST S/W
OF THE CAPITAL REGION.

&&

.SHORT TERM /6 AM FRIDAY MORNING THROUGH SATURDAY NIGHT/…
FRIDAY-FRI NT…LOW CONFIDENCE PERSISTS DURING THIS TIME
FRAME…AS 12Z/DETERMINISTIC MODELS VARY WIDELY IN OVERALL QPF.
THE NAM IS GREATEST…IMPLYING HIGH END ADVISORY…OR EVEN LOW END
WARNING LEVELS SNOWS FOR AREAS N AND E OF ALBANY…INTO THE SW
ADIRONDACKS. THE 12Z/GFS IS A BIT LESS…IMPLYING MORE ADVISORY
LEVEL SNOWS…WHILE THE 12Z/ECMWF HAS MUCH LESS OVERALL
PRECIP…SPLITTING THE GREATEST QPF SE AND N OF THE REGION…WITH
MORE EMPHASIS ON A WEAK SECONDARY LOW DEVELOPING E OF LONG
ISLAND…LIMITING OVERALL MOISTURE INFLUX INTO OUR REGION UNTIL
THE OCCLUDED FRONT MOVES ACROSS THE REGION FRI EVENING. FOR
NOW…HAVE GENERALLY BLENDED ALL MODELS…SIDING HIGHER THAN THE
ECMWF…BUT A BIT LESS THAN THE NAM. THIS BRINGS A PERIOD OF SNOW
THROUGH THE MORNING HOURS FROM ALBANY N AND E…ALTHOUGH INTENSITY
MAY DIMINISH A BIT AS STRONGEST ISENTROPIC LIFT SLIDES INTO
SOUTHERN NEW ENGLAND. EITHER WAY…IT APPEARS THAT MUCH OF THE
REGION SHOULD EXPERIENCE A RATHER MESSY MORNING COMMUTE…WITH AT
LEAST 1-3 INCHES OF SNOWFALL IN VALLEY AREAS FROM ALBANY
SOUTH…EXCEPT AN INCH OR LESS ACROSS THE MID HUDSON VALLEY AND
SOUTHERN LITCHFIELD CO…WITH 2-4 INCHES EXPECTED FOR AREAS NORTH
INTO NORTHERN SARATOGA COUNTY AND INTO THE EASTERN MOHAWK
VALLEY…WITH 3-6 INCHES EXPECTED ACROSS HIGHER ELEVATIONS ACROSS
THE CATSKILLS/SCHOHARIE VALLEY…BERKSHIRES…SOUTHERN GREENS AND
SOUTHERN ADIRONDACKS…WITH LOCALLY UP TO 8 INCHES POSSIBLE IN
PORTIONS OF THE WESTERN DACKS. A PERIOD OF FREEZING RAIN IS
POSSIBLE DURING THE MID TO LATE MORNING HOURS AS WELL ACROSS
HIGHER ELEVATIONS AS PRECIP INTENSITY DIMINISHES. THERE SHOULD BE
A LULL IN PRECIP INTENSITY FROM MID MORNING INTO THE MID AFTERNOON
HOURS…BEFORE INCREASING AGAIN FROM W TO E AS THE OCCLUDED FRONT
APPROACHES. AT THAT TIME…BOUNDARY LAYER TEMPS SHOULD BE WARM
ENOUGH FOR RAIN IN VALLEYS…AND WET SNOW ACROSS HIGHER
ELEVATIONS. THIS NEXT SURGE OF PRECIP WITH THE OCCLUDED FRONTAL
PASSAGE WILL NEED TO BE WATCHED…AS SUFFICIENT MID LEVEL COOLING
COULD ALLOW FOR ANOTHER BURST OF SNOW TO OCCUR FRI EVE…EVEN IN
VALLEY REGIONS FROM ALBANY NORTHWARD. PRECIP SHOULD TRANSITION TO
SNOW SHOWERS LATER FRI EVE AND OVERNIGHT…WITH INCREASING W/NW
WINDS DEVELOPING…POSSIBLY GUSTING OVER 40 MPH. WILL HIGHLIGHT
POTENTIAL FOR GUSTY WINDS…PERHAPS REACHING ADVISORY LEVELS…IN
HWOALY. FOR TEMPS…GENERALLY SIDED WITH MET MOS.

SAT-SAT NT…DURING THIS TIME…LAKE EFFECT/ENHANCED
SNOWBANDS…AND OROGRAPHIC LIFT MAY ALLOW FOR ADDITIONAL SNOWFALL
ACROSS THE SOUTHERN ADIRONDACKS…AND POSSIBLY ACROSS WEST FACING
SLOPES FROM THE SOUTHERN GREENS INTO THE BERKSHIRES.
OTHERWISE…STRONG/GUSTY WINDS WILL PERSIST THROUGH
SATURDAY…GRADUALLY DIMINISHING SAT NT AS COLDER AIR MOVES INTO
THE REGION FROM THE NW. ACCEPTED BLEND OF MAV/MET MOS FOR TEMPS.

&&

.LONG TERM /SUNDAY THROUGH THURSDAY/…
QUIET WEATHER IS EXPECTED FOR MUCH OF THE LONG TERM PERIOD AS HIGH
PRESSURE CRESTS OVER OUR REGION ON SUNDAY AND SLIDES OFF THE EASTERN
SEABOARD SUNDAY NIGHT. THE NEXT CLIPPER TYPE SYSTEM IS EXPECTED TO
TRACK WELL TO OUR NORTH ACROSS SOUTHERN CANADA MONDAY AND MONDAY
NIGHT WITH THE SOUTHERN EDGE OF THE PRECIPITATION SHIELD REMAINING
NORTH OF OUR REGION. THE DRY WEATHER LOOKS AS THOUGH IT WILL COME TO
AN END LATE TUESDAY NIGHT OR WEDNESDAY MORNING WITH UNSETTLED
WEATHER LASTING THROUGH THURSDAY AS A LOW PRESSURE SYSTEM LIFTS EAST
NORTHEAST TOWARD OUR REGION FROM THE OHIO VALLEY.

SUNDAY AND SUNDAY NIGHT APPEAR TO BE THE TWO COLDEST PERIODS IN THE
LONG TERM WITH HIGHS ON SUNDAY RANGING FROM THE MID 20S NORTHWEST TO
THE LOWER 40S SOUTHEAST AND LOWS SUNDAY NIGHT RANGING FROM THE
SINGLE DIGITS NORTHWEST TO LOWER 20S SOUTHEAST.

MONDAY THROUGH TUESDAY ARE EXPECTED TO BE CONSIDERABLY MILDER AS A
RETURN FLOW DEVELOPS WITH HIGH PRESSURE OFF THE EAST COAST. HIGHS ON
MONDAY AND TUESDAY ARE EXPECTED TO RANGE FROM THE LOW TO MID 30S
NORTHWEST TO THE MID TO UPPER 40S SOUTHEAST WITH LOWS MONDAY NIGHT
RANGING FROM THE UPPER TEENS AND LOWER 20S NORTHWEST TO AROUND 30
SOUTHEAST.

TUESDAY NIGHT THROUGH THURSDAY ARE EXPECTED TO BE UNSETTLED WITH AT
LEAST A CHANCE OF PRECIPITATION FROM LATE TUESDAY NIGHT THROUGH
THURSDAY AS A STORM SYSTEM TRACKS EAST NORTHEAST FROM THE OHIO
VALLEY WITH THE ECMWF INDICATING A SECONDARY COASTAL LOW DEVELOPING
BY THURSDAY MORNING. PTYPE THIS FAR OUT IS DIFFICULT TO
PINPOINT…HOWEVER WITH COLDER AIR FUNNELING IN BEHIND THE CLIPPER
SYSTEM TUESDAY NIGHT…IT MAY BE COLD ENOUGH FOR MOSTLY SNOW ACROSS
THE NORTHERN MOUNTAINS AND A MIX OF RAIN AND SNOW ELSEWHERE. EXPECT
LOWS TUESDAY NIGHT TO BE IN THE TEENS AND 20S WITH HIGHS ON
WEDNESDAY AND THURSDAY GENERALLY RANGING FROM THE LOW TO MID 30S
NORTHWEST TO THE LOW TO MID 40S SOUTHEAST. LOWS WEDNESDAY NIGHT ARE
EXPECTED TO RANGE FROM THE UPPER TEENS AND LOWER 20S NORTHWEST TO
THE UPPER 20S TO AROUND 30 SOUTHEAST.

&&

.AVIATION /03Z FRIDAY THROUGH TUESDAY/…
A LOW PRESSURE SYSTEM WILL APPROACH FROM THE OHIO VALLEY TONIGHT
BRINGING A WINTRY MIX WITH VFR CONDITIONS GIVING WAY TO MVFR/IFR
CONDITIONS RETURNING BETWEEN 07Z AND 09Z. THE WINTRY MIX IS THEN
EXPECTED TO GRADUALLY CHANGE TO ALL RAIN AT THE TAF SITES BTWN 13Z
AND 18Z WITH KGFL BEING THE SLOWEST TO CHANGE TO RAIN. MVFR
CONDITIONS ARE EXPECTED AT THE TAF SITES FROM 16Z-18Z UNTIL THE
END OF THE TAF PERIOD AT 00Z SAT.

THERMAL ADVECTION PCPN WILL MOVE INTO THE REGION AFTER MIDNIGHT.
SNOW SHOULD BE THE PREDOMINANT PRECIPITATION TYPE DURING THE ONSET
AROUND 07Z-09Z….EXCEPT AT KPOU WHERE A MIXTURE OF SNOW…SLEET
AND RAIN IS EXPECTED. MODEL SOUNDINGS AND PARTIAL THICKNESS
VALUES SUPPORT MAINLY SNOW AND SLEET PRIOR TO 12Z…WITH A
TRANSITION TO RAIN BEGINNING AT KPOU ARND 13Z…KALB BTWN 14Z AND
16Z AND KGFL AFT 18Z. SOME FREEZING RAIN IS ALSO PSBL DURING THE
EARLY TO MID MORNING HOURS…BUT WITH UNCERTAINTY ON TIMING HAVE
LEFT OUT OF TAFS FOR NOW. ONCE THE PRECIPITATION CHANGES TO RAIN
OR A MIX THE INTENSITY COULD DIMINISH AND CONDITIONS COULD BE
BETTER THAN FORECASTED IF A DRY SLOT MOVES ACROSS THE
REGION…STAY TUNED.

WINDS WILL BE LIGHT AND VARIABLE THROUGH MUCH OF THE OVERNIGHT AND
THEN BECOME EAST NORTHEAST AT 6 KTS OR LESS FRIDAY MORNING AND EAST
AROUND 6 KTS FRIDAY AFTERNOON.

OUTLOOK….
FRI…MVFR/IFR CIGS/VSBYS…TRANSITION TO RA FROM KPOU TO KGFL IN
THE MORNING. BECOMING WINDY.
FRI NGT…VFR/MVFR…CHC -SHSNS.
SAT…VFR…SLIGHT CHC -SHSN. WINDY.
SAT NIGHT-SUN…VFR…DECREASING WINDS.
MON…VFR SLIGHT CHC -SHRA/-SHSN.
TUE…VFR.

&&

.HYDROLOGY…
HYDRO PROBLEMS APPEAR MINIMAL THE NEXT FIVE DAYS. LOW PRESSURE
APPROACHING THE REGION LATE THURSDAY NIGHT INTO FRIDAY HAS THE
POTENTIAL TO BRING MODERATE PRECIPITATION AMOUNTS TO THE REGION
WITH AMOUNTS RANGING FROM LESS THAN HALF AN INCH…TO POSSIBLY UP
TO AN INCH. SOME…IF NOT MUCH OF THIS SHOULD FALL AS FROZEN
PRECIPITATION…WHICH WOULD LEAD TO MINIMAL IMPACTS ON RIVERS AND
STREAMS.

THE PROBABILITIES FOR FLOODING IS GENERALLY BELOW NORMAL DUE TO
BELOW NORMAL SNOWPACK AND LACK OF RIVER ICE. PLEASE REFER TO OUR
WINTER/SPRING FLOOD POTENTIAL OUTLOOK (ALBESFALY) ISSUED ON
FEBRUARY 16TH FOR DETAILS. NEXT ISSUANCE OF THIS PRODUCT IS
SCHEDULED FOR MARCH 1ST 2012.

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…WINTER WEATHER ADVISORY UNTIL 2 PM EST FRIDAY FOR NYZ038>040-
047-048-051-058-063.
WINTER WEATHER ADVISORY FROM 3 AM TO 6 PM EST FRIDAY FOR
NYZ032-033-042-043-054-061-082-083.
MA…WINTER WEATHER ADVISORY FROM 3 AM TO 6 PM EST FRIDAY FOR
MAZ001-025.
VT…WINTER WEATHER ADVISORY FROM 3 AM TO 6 PM EST FRIDAY FOR
VTZ013>015.

&&

$$
SYNOPSIS…KL/GJM/NAS
NEAR TERM…KL/11
SHORT TERM…KL
LONG TERM…11
AVIATION…11/NAS
HYDROLOGY…KL/GJM

Unless otherwise stated, the content of this page is licensed under Creative Commons Attribution-ShareAlike 3.0 License