February 5, 2012

000
FXUS61 KALY 051445
AFDALY

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ALBANY NY
945 AM EST SUN FEB 5 2012

.SYNOPSIS…
HIGH PRESSURE WILL BUILD ACROSS OUR REGION INTO THIS EVENING WITH
TEMPERATURES NEAR NORMAL TO SLIGHTLY ABOVE NORMAL FOR EARLY
FEBRUARY. A WARM FRONT IS EXPECTED TO SLIDE THROUGH THE REGION
LATE TONIGHT RESULTING IN MILDER CONDITIONS ON MONDAY.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/…
AS OF 945 AM EST…MAINLY SUNNY SKIES AND COOL CONDITIONS REMAINED
ACROSS THE FA WITH TEMPS MAINLY IN THE TEENS TO MID 20S. EXPECT
MOST AREAS TO BE MOSTLY SUNNY TO SUNNY TODAY WITH HIGH PRESSURE IN
CONTROL…ALTHOUGH CLOUDS WILL GRADUALLY INCREASE ACROSS NORTHWEST
PORTION OF FA DURING THE AFTERNOON. EXPECT HIGHS TODAY TO BE
A FEW DEGREES COOLER THAN SATURDAY…RANGING FROM THE UPPER 20S
NORTHWEST TO AROUND 40 SOUTHEAST.

CLOUD SHIELD IS SLOWLY BUILDING EAST…AND ADJUSTING SOME SKY
GRIDS BASED ON SATELLITE TRENDS. AS THE CLOUD SHIELD HEADS
EAST…IT MAY TEND TO SLOWLY BREAK UP AND MIX OUT…SO THAT WHEN
IT REACHES EASTERN NY…IT MAY BE A BROKEN VARIABLE SCATTERED
CLOUD LAYER.

SO…EVEN WITH THE CLOUD ADJUSTMENTS…THE MIXING
POTENTIAL IS STILL ROUGHLY THE SAME…SUPPORTING HIGH TEMPERATURES
NEAR CURRENT FORECASTED HIGH TEMPERATURES. FEW OTHER ADJUSTMENTS
OTHER THAN THE SKY COVER AND MINOR CHANGES TO TEMPERATURES BASED
ON CURRENT OBSERVATIONS AND TRENDS.

PREV AFD BELOW…

CLEAR ACROSS THE REGION BUT AREA OF CLOUDS SINKING SOUTH INTO THE
GREAT LAKES OUT OF CANADA IN AN AREA OF WARM ADVECTION ON THE
WESTERN PERIPHERY OF A LOW LEVEL RIDGE. IT SHOULD TAKE MUCH OF
THE DAY FOR THE LOW LEVEL RIDGING TO BUILD EAST AND THE WARM
ADVECTION TO SPREAD EAST. OUR REGION SHOULD SEE QUITE A BIT OF SUN
THROUGH THIS MORNING…THEN SOME OF THE CLOUDINESS SHOULD BUILD
EAST THROUGH THE AFTERNOON. SO…SOME WESTERN AND NORTHERN AREAS
COULD SEE A MOSTLY CLOUDY SKY BY LATE AFTERNOON. LIGHT WINDS
SHOULD LIMIT MIXING…AND WITH A RELATIVELY COLD START THIS
MORNING…HIGH TEMPERATURES SHOULD BE ON THE COOLER SIDE OF
GUIDANCE. SO..HIGHS IN THE MID 30S TO AROUND 40…SOME UPPER 20S
IN THE SOUTHERN ADIRONDACKS.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH TUESDAY NIGHT/…
DEGREE OF CLOUD COVER TONIGHT DEPENDS ON THE CHARACTER OF THE WARM
ADVECTION AND WHETHER ANY LAKE EFFECT MOISTURE GETS ENTRAINED IN
THE BOUNDARY LAYER ALONG WITH ANY POTENTIAL LOW LEVEL SUBSIDENCE
INVERSIONS THAT COULD TRAP SOME LOW LEVEL MOISTURE. FOR NOW…
SUSPECTING MOST AREAS WILL SEE SOME CLOUD COVER IN THE EVENING…
BUT WHETHER IT IS PREDOMINANTLY SCATTERED OR BROKEN IS UNKNOWN.
ALSO…HOW LONG INTO THE NIGHT MIGHT ANY CLOUD COVER LINGER SINCE
WARM ADVECTION IS EXPECTED THROUGH THE NIGHT? NOT STRAYING TOO FAR
FROM GUIDANCE…BUT GOING ON THE HIGHER SIDE OF GUIDANCE AS WARM
ADVECTION AND INCREASING BOUNDARY LAYER WINDS SUGGEST EVEN WITH
PERIODS OF CLEARING…AND LIGHT SURFACE WINDS…TEMPERATURES
SHOULD NOT BE ALE TO DROP AS MUCH AS THEY COULD IF THE LOW LEVEL
RIDGING WERE MORE PROXIMATE TO THE REGION. LOWS IN THE 20S…WITH
UPPER TEENS IN THE SOUTHERN ADIRONDACKS.

WEST FLOW INCREASES THROUGH THE DAY MONDAY…AND WEST TO SOUTHWEST
WINDS COULD BE BREEZY AT TIMES. CONTINUED WARM ADVECTION SHOULD
WARM BOUNDARY LAYER TEMPERATURES AND AID IN MIXING. SO..
TEMPERATURES SHOULD REACH THE MID TO UPPER 40S IN MOST AREAS…
AROUND 50 SOUTHERN AREAS AND AROUND 40 SOUTHERN ADIRONDACKS.

A COLD FRONT TRACKS THROUGH THE REGION MONDAY NIGHT WITH VERY
LITTLE MOISTURE ASSOCIATED WITH IT. STRONGER COLD ADVECTION LOOKS
TO BEGIN LATER MONDAY NIGHT AND EARLY TUESDAY MORNING. SO LOWS
MONDAY NIGHT SHOULD BE ON THE WARMER SIDE OF GUIDANCE…IN THE
20S…WITH AROUND 20 SOUTHERN ADIRONDACKS.

COLD ADVECTION CONTINUES WITH SOME POSSIBLE BRIEF PERIOD OF LAKE
EFFECT SNOWS DEVELOPING LATE MONDAY NIGHT AND TUESDAY…POSSIBLY
EXTENDING INTO THE SOUTHERN ADIRONDACKS. THE BOUNDARY LAYER WINDS
LOOK RELATIVELY LIGHT AND THE INVERSION LEVELS ARE IN QUESTION.
FOR NOW JUST INDICATING SLIGHT CHANCES THERE UNTIL MESOSCALE
PARAMETERS BECOME CLEARER. LOW LEVEL RIDGING BUILDS BACK INTO THE
REGION TUESDAY NIGHT WITH LIGHT WINDS AND MOSTLY CLEAR SKY. HIGHS
TUESDAY IN THE UPPER 30S TO MID 40S…BUT UPPER 20S SOUTHERN
ADIRONDACKS. LOWS TUESDAY NIGHT IN THE UPPER TEENS TO MID 20S…
SOME READINGS JUST ABOVE ZERO POSSIBLE IN PARTS OF THE SOUTHERN
ADIRONDACKS.

&&

.LONG TERM /WEDNESDAY THROUGH SATURDAY/…
THE PERIOD STARTS OUT RATHER QUIET WITH HIGH PRESSURE CENTERED OVER
OR JUST NORTH OF THE REGION ON WEDNESDAY. MODELS HAVE BEEN
CONSISTENT IN SHOWING A FAST-MOVING SHORTWAVE TROF APPROACHING FROM
THE OHIO VALLEY REGION AND MOVING ACROSS OUR AREA WEDNESDAY NIGHT
INTO THURSDAY MORNING. THE TRACK OF THIS WEAK SYSTEM IS STILL IN
QUESTION…WITH THE GFS AND ECMWF WAVERING FROM RUN TO RUN. STILL
ENOUGH EVIDENCE TO WARRANT CONTINUING MENTION OF LOW CHANCE POPS FOR
SOME LIGHT SNOW.

THE FLOW ALOFT REMAINS MAINLY ZONAL ACROSS MUCH OF THE EASTERN
CONUS…SO NO REAL COLD AIR EXPECTED BEHIND THE SHORTWAVE FOR
THURSDAY WITH TEMPS CONTINUING TO BE ABOVE NORMAL.

THE NEXT SYSTEM TO IMPACT OUR REGION WILL BE AN ARCTIC COLD FRONT
THAT WILL APPROACH FROM SOUTHEAST CANADA AND THE GREAT LAKES ON
FRIDAY. GUIDANCE IN PRETTY GOOD AGREEMENT WITH TIMING OF THE
FRONT…HOWEVER DIVERGING SOLUTIONS ARE NOTED BY FRIDAY NIGHT AS THE
GFS INITIALLY STALLS THE FRONT OVER THE AREA AND DEVELOPS A WAVE
ALONG IT. THE ECMWF HOWEVER…HAS THE FRONT CLEANLY SWEEPING THROUGH
WITH HIGH PRESSURE QUICKLY BUILDING IN BY SATURDAY. SINCE THIS
LATEST RUN OF THE GFS IS THE FIRST TO LATCH ONTO THIS SOLUTION WILL
NOT BUY IN JUST YET…BUT A FEW GFS ENSEMBLE MEMBERS INDICATING
DECENT QPF SO WILL AT LEAST MENTION LOW CHANCE POPS AT THIS TIME TO
ACCOUNT FOR SOME UNCERTAINTY.

FOR WHAT ITS WORTH…ON SATURDAY THE GFS HAS THE SURFACE CYCLONE
PASSING JUST EAST OF CAPE COD AS IT DEEPENS…WHICH WOULD RESULT IN
ACCUMULATING SNOWFALL FOR MUCH OF OUR AREA. IN CONTRAST…THE ECMWF
HAS A LARGE AREA OF HIGH PRESSURE BUILDING IN DURING THIS TIME SO
THERE IS MUCH UNCERTAINTY FOR THE END OF NEXT WEEK.

&&

.AVIATION /15Z SUNDAY THROUGH THURSDAY/…
VFR CONDITIONS ARE EXPECTED TO PERSIST THROUGH THE 24 HOUR PERIOD
ENDING 12Z MONDAY AT THE KALB/KPOU/KGFL TAF SITES. STRATUS DECK IN
VFR RANGE SLOWLY ENCROACHING FROM THE WEST THROUGH CENTRAL NY…BUT
IT IS UNCLEAR WHETHER THE CLOUD DECK WILL REMAIN WIDESPREAD AS IT
MOVES INTO EASTERN NY DUE TO BETTER MIXING POTENTIAL DURING THE
DAYLIGHT HOURS. EITHER WAY…VFR CONDITIONS WILL PREVAIL.

WINDS WILL INITIALLY BE LIGHT AND VARIABLE…BECOMING NORTHWEST
AROUND 5-8 KT AT KALB/KPOU…AND SOUTH-SOUTHWEST AT KGFL AROUND 5 KT
BY AFTERNOON. WINDS WILL BECOME LIGHT AN VARIABLE ONCE AGAIN AFTER
SUNSET.

OUTLOOK…
MON-WED…MAINLY VFR…NO SIG WX.
WED NT…VFR/MVFR…CHC -SN.
THU…VFR/MVFR…CHC -SHRA/-SHSN.

&&

.HYDROLOGY…
HYDRO PROBLEMS ARE NOT ANTICIPATED THROUGH EARLY NEXT WEEK WITH
LITTLE IF ANY PRECIPITATION EXPECTED. TEMPERATURES ARE EXPECTED
TO BE NORMAL TO SLIGHTLY ABOVE NORMAL OVER THE WEEKEND WITH
TEMPERATURES MODERATING AGAIN EARLY NEXT WEEK. SOME GAGES ARE STILL
BEING IMPACTED BY ICE ACROSS NORTHERN PORTIONS OF THE HSA.

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…11/NAS
SHORT TERM…NAS
LONG TERM…JPV
AVIATION…JPV
HYDROLOGY…NAS

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