January 25, 2012 Forecast Discussion

000
FXUS61 KALY 251748
AFDALY

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ALBANY NY
1248 PM EST WED JAN 25 2012

.SYNOPSIS…
TRANQUIL CONDITIONS ARE IN THE FORECAST FOR THE MID WEEK PERIOD
AS A RIDGE OF HIGH PRESSURE TRACKS ACROSS THE AREA. THE NEXT STORM
SYSTEM IS EXPECTED TO IMPACT THE REGION LATE THURSDAY INTO FRIDAY
WITH MIXED PRECIPITATION.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/…
AS OF 1245 PM EST…JUST SOME MINOR TWEAKS TO GRIDS…MAINLY TO
ADD SOME FLURRIES ACROSS CENTRAL AND NORTHERN PORTIONS OF THE
REGION…AS SOME FLURRIES/SNOW GRAINS CONTINUE. SOME CLEARING HAS
OCCURRED ACROSS THE MID HUDSON VALLEY REGION…AND MAY EXPAND INTO
PORTIONS OF SOUTHERN LITCHFIELD COUNTY DURING THE AFTERNOON AS
DOWNSLOPING STRENGTHENS…SO HAVE INDICATED A SLIGHT DECREASING
TREND IN CLOUD COVER IN THIS REGION…BEFORE CLOUDS INCREASE YET
AGAIN FROM THE W AROUND OR AFTER SUNSET. TEMPS IN MOST AREAS
SHOULD HOLD GENERALLY STEADY THROUGH THE AFTERNOON…ALTHOUGH SOME
RISES ARE EXPECTED WHERE SUNSHINE OCCURS FROM THE MID HUDSON
VALLEY INTO SOUTHERN LITCHFIELD COUNTY…WHERE MAX TEMPS MAY REACH
THE MID 40S IN SOME AREAS.

PREVIOUS DISCUSSIONS FOLLOW…

AS OF 10 AM…OVERCAST CONDITIONS ALONG WITH TEMPS IN THE UPPER
20S TO UPPER 30S WERE COMMON ACROSS THE FA. ABUNDANT LOW LEVEL
MOISTURE REMAINS TRAPPED ACROSS FA BENEATH A STRONG LOW LEVEL
INVERSION. THUS EXPECT CLOUDS TO LINGER THROUGH THE AFTERNOON WITH
LITTLE CHANGE IN TEMPS AS READINGS ONLY EXPECTED TO RISE ANOTHER
FEW DEGREES FROM CURRENT VALUES. ANY LINGERING SCATTERED LIGHT
SNOW SHOWERS AND FLURRIES ARE EXPECTED TO GRADUALLY DIMINISH AS
FLOW STARTS TO BECOME ANTICYCLONIC.

LITTLE TO NO CHANGE IN THE SKY COVER ACROSS THE REGION.
TEMPERATURES ARE REACHING THEIR LOWS. JUST AN ISOLATED SNOW
SHOWER/FLURRY POSSIBLE IN THE WESTERN MOHAWK VALLEY AND SOUTHERN
ADIRONDACKS THIS MORNING. VERY FEW ADJUSTMENTS IF ANY THROUGH THIS
MORNING BASED ON CURRENT OBSERVATIONS AND TRENDS.

PREV AFD BELOW…

CLOUD COVER STILL HOLDING OVER THE REGION IMPLYING THE INVERSION
AND TRAPPED MOISTURE CONTINUES…ESPECIALLY WITH FLOW OFF THE
GREAT LAKES. GUIDANCE TRYING TO HINT AT SOME OF THE CLOUDS
BREAKING UP BY THIS AFTERNOON…BUT GUIDANCE MAY BE OPTIMISTIC
BASED ON UPSTREAM CONDITIONS. SOME INCREASED SUBSIDENCE IS LIKELY
LATER THIS AFTERNOON AS LOW LEVEL RIDGING BUILDS IN.WHICH COULD
HELP MIX OUT THE CLOUD LAYER.

SOME DEGREE OF COLD ADVECTION SHOULD OCCUR TODAY…NOT STRONG…
BUT ENOUGH THAT IF ANY GLIMPSES OF SUN OCCUR…TEMPERATURES MAY
NOT RISE MUCH. STILL…TEMPERATURES ARE STARTING RELATIVELY
WARM…SO TEMPERATURES SHOULD RISE AT LEST A FEW DEGREES FROM
MORNING LOWS. SOME GUSTY NW WINDS WILL EASE A LITTLE THIS
MORNING…THEN DIMINISH MORE IN THE AFTERNOON.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH FRIDAY NIGHT/…
WEAK LOW LEVEL RIDGING SHOULD BE OVER THE REGION…BUT SOME WARM
ADVECTION ALOFT SHOULD BRING A PERIODS OF CLOUDINESS ACROSS THE
REGION. THE TIMING OF THE CLEARING IN GUIDANCE LOOKS TO BE TOWARD
SUNRISE…AND THE TIMING OF CLEARING WILL DETERMINE IF
TEMPERATURES CAN FALL BELOW GUIDANCE OR NOT. TEMPERATURES WOULD BE
ABOVE GUIDANCE IF IT REMAINS CLOUDY ALL NIGHT…WE WILL SEE. LOWS
GENERALLY IN THE 20S WITH TEENS IN HIGHER ELEVATIONS.

STRONGER SYSTEM APPROACHES THURSDAY WITH INCREASING CLOUDS AND
WARM ADVECTION AS LOW LEVEL RIDGING BUILDS EAST. HIGHS THURSDAY IN
THE 30S…BUT AROUND 40 IN SOUTHERN AREAS. SOME RAIN MAY JUST BEGIN
TO BUILD INTO THE EASTERN CATSKILLS AND MID HUDSON VALLEY AROUND
SUNSET.

PRECIPITATION SPREADS ACROSS THE REGION THURSDAY NIGHT…AND BASED
ON THERMAL PROFILES…AND LOW LEVEL WET BULB POTENTIAL…
TEMPERATURES COULD FALL A FEW DEGREES THROUGH THE EVENING. THERMAL
PROFILES ALSO SUGGEST MIXED RAIN AND SNOW IN AREAS THAT ARE JUST
ABOVE FREEZING…AND SNOW AND SLEET IN AREAS BELOW FREEZING. ALL
AREAS COULD SEE A PERIOD OF FREEZING RAIN THURSDAY NIGHT AS
WARMING ALOFT TAKES PLACE. SOUTHERN AREAS MAY OR MAY NOT SEE ANY
FREEZING RAIN…WHILE POTENTIAL LENGTH OF ANY PERIOD OF FREEZING
RAIN EVERYWHERE ELSE DEPENDS ON HOW FAR NORTH AND HOW WELL
PROTECTED A VALLEY IT MAY OCCUR.

PRECIPITATION TYPES AND TRANSITIONS NOT WELL RESOLVED IN TEXT
FORMATTERS…SO THE BOTTOM LINE IS THAT A MIX IS LIKELY IN MANY
AREAS INCLUDING A CHANCE OF FREEZING RAIN…THAT SHOULD TRANSITION
TO RAIN FROM SOUTH TO NORTH. WITH SUCH UNCERTAINTIES…JUST
KEEPING AS A CHANCE OF FREEZING RAIN…AND WILL MENTION THE
POSSIBILITY IN THE HWO. NORTHERN AREAS COULD SEE LIGHT TO MODERATE
SNOW ACCUMULATIONS BEFORE ANY PRECIPITATION TRANSITION.

ON FRIDAY…PRECIPITATION EVENTUALLY BECOMES RAIN EVERYWHERE BY
MIDDAY…AND BECOMES SHOWERY DURING THE AFTERNOON WITH PARTIAL
CLEARING POSSIBLE BEFORE SUNSET. HIGHS IN THE 40S IN MANY AREAS
DUE TO BREEZY NW WINDS HELPING MIXING BEFORE THE DEEPER COLD
ADVECTON OCCURS. MORE CLEARING AND COOLING FRIDAY NIGHT…WITH
LOWS IN THE 20S…SOME TEENS IN THE SOUTHERN ADIRONDACKS.

&&

.LONG TERM /SATURDAY THROUGH TUESDAY/…
AS STRONG PACIFIC ENERGY COMES ASHORE ACROSS BRITISH COLUMBIA…THIS
WILL ASSIST WITH A DIGGING TROUGH OVER THE CENTER OF THE NATION AND
REMAINS PROGRESSIVE AS IT MIGRATES EASTWARD THIS WEEKEND. THIS TYPE
OF PATTERN DOES NOT ALLOW FOR TOO MUCH MOISTURE WITH THE EXCEPTION
OF DOWNWIND LAKE ONTARIO WITH FAVORABLE COLD ADVECTION. SO POPS
WILL REMAIN RATHER LOW THROUGH THIS WEEKEND…WITH SLIGHTLY ELEVATED
POPS FOR SUNDAY AS THE BASE OF THE TROUGH TRACKS ACROSS THE REGION.
THERE WILL BE A WINDOW FOR LAKE EFFECT SNOW ACCUMULATIONS DURING
SUNDAY…BUT PLENTY OF TIME TO WATCH THIS POTENTIAL.

OTHERWISE…WITH THE FROPA EXPECTED SUNDAY MORNING…850MB TEMPS
DROP BACK INTO THE NEGATIVE TEENS TO MAKE FOR A COLDER DAY THAN
SATURDAY BY A GOOD 5-10 DEGREES.

A BRIEF RIDGE OF HIGH PRESSURE SLIDES ACROSS THE AREA MONDAY. AS
THIS HIGH SLIDES OFF THE MID ATLANTIC COAST…WARM ADVECTION REGIME
UNFOLDS UPSTREAM WITH OVERRUNNING PATTERN EVOLVING OVER THE GREAT
LAKES REGION. THIS WILL INCREASE CLOUD COVER AND THE CHANCE FOR
LIGHT STRATIFORM EVENT DURING THE TIMEFRAME OF MONDAY NIGHT INTO
TUESDAY.

&&

.AVIATION /18Z WEDNESDAY THROUGH MONDAY/…
LOW STRATUS REMAINS TRAPPED BENEATH A STRONG INVERSION EARLY THIS
AFTN. THIS IS ALLOWING FOR WIDESPREAD OVC SKIES WITH HIGH END
MVFR/LOW END VFR CIGS ACROSS THE REGION. THIS WILL CONTINUE THROUGH
THE REMAINDER OF THE AFTN AT ALL TAF SITES. WESTERLY WINDS WILL
REMAIN GUSTY AT TIMES AT KALB…AS AIR IS FUNNELED DOWN THE MOHAWK
VALLEY. THESE WINDS WILL DIMINISH BY THE EARLY EVENING HOURS.

TOWARDS THIS EVENING…THE LOWER CLOUDS WILL START TO BREAK UP AS
DRIER AIR MOVES INTO THE REGION…ALLOWING FOR VFR CONDITIONS TO
RETURN TO ALL SITES. SOME MID LEVEL CLOUDINESS WILL CONTINUE TO
SPREAD ACROSS THE REGION FOR TONIGHT INTO TOMORROW MORNING AS A
STORM OVER THE DEEP SOUTH AND TENNESSEE VALLEY HEADS TOWARDS THE
AREA. HOWEVER…FLYING CONDITIONS SHOULD REMAIN VFR WITH NO PRECIP
RIGHT THROUGH 18 UTC ON THURSDAY. WINDS OVERNIGHT WILL BE NEARLY
CALM AND SWITCH TO AN EAST TO SOUTHEAST DIRECTION FOR THURSDAY
MORNING AT LIGHT SPEEDS.

OUTLOOK…
THU NT-FRI AM…MVFR/IFR. MIXED PCPN TRANSITIONING TO -RA.
FRI AFTN…VFR/MVFR. CHC -SHRA EARLY.
FRI NT-SAT…VFR. NO SIG WX.
SAT NT-SUN…VFR/MVFR/IFR. CHC -SHSN/-SHRA.
SUN NT-MON…VFR. NO SIG WX.

&&

.HYDROLOGY…
NO HYDRO PROBLEMS EXPECTED FOR THE NEXT SEVERAL DAYS.

THE NEXT PRECIPITATION EVENT IS NOT EXPECTED UNTIL THURSDAY NIGHT
AND FRIDAY. LIQUID EQUIVALENT AMOUNTS WITH THIS EVENT WILL RANGE
FROM A QUARTER INCH TO THREE QUARTERS OF AN INCH. SOME OF THIS WILL
FALL AS SNOW OR MIXED PRECIPITATION…SO HYDRO IMPACTS WILL BE
MINIMAL.

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/11/NAS
SHORT TERM…NAS
LONG TERM…BGM
AVIATION…FRUGIS
HYDROLOGY…NAS

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