Frbruary 19, 2013 Forecast Discussion

000
FXUS61 KALY 191802
AFDALY

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ALBANY NY
102 PM EST TUE FEB 19 2013

.SYNOPSIS…
LOW PRESSURE OVER THE NORTHERN GREAT LAKES REGION AND AN
ASSOCIATED COLD FRONT WILL MOVE ACROSS OUR REGION THIS AFTERNOON
INTO THIS EVENING WITH A LIGHT MIXTURE OF RAIN AND SNOW. AN UPPER
LEVEL DISTURBANCE WILL SLIDE OVER OUR REGION ON WEDNESDAY WHICH
WILL KEEP PLENTY OF CLOUDS AROUND ALONG SNOW SHOWERS…MAINLY OVER
THE MOUNTAINS AND MOHAWK VALLEY.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/…
PRECIPITATION MOVING INTO WESTERN AREAS AND RAPIDLY EXPANDING
EAST. PRECIPITATION STARTS AS RAIN OR A MIX OF RAIN AND
SNOW…THEN COLUMN COOLING AND COOLING TO LOW LEVEL WET BULB
TEMPERATURES COOLS TEMPERATURES ENOUGH TO CHANGE TO SOME WET SNOW.
THIS WILL LIKELY BE THE TREND INMOST AREAS AS THE PRECIPITATION
SPREADS EAST. SO…SOME MINOR ADJUSTMENTS TO THE TEMPERATURES AND
EVOLUTION OF PRECIPITATION TYPES…BUT JUST MINOR CHANGES. STILL A
CHANCE AT SOME DUSTINGS TO A SLUSHY INCH IN SOME AREAS BEFORE
STEADIER PRECIPITATION ENDS THIS EVENING. SOME LAKE EFFECT SNOW
SHOWER ACTIVITY COULD EXTEND INTO THE SOUTHERN ADIRONDACKS LATER
TONIGHT BUT WILL ANALYZE THIS CLOSER ONCE ALL THE NEW GUIDANCE IS
IN LATER THIS AFTERNOON

&&

.SHORT TERM /6 PM THIS EVENING THROUGH THURSDAY/…
THE AFOREMENTIONED COLD FRONT WILL SWEEP ACROSS OUR REGION THIS
EVENING…BRINGING ANOTHER SHOT OF CHILLY MODIFIED ARCTIC AIR. WHILE
THE SURFACE FEATURES (LOW PRESSURE AND COLD FRONT) WILL QUICKLY MOVE
TO OUR EAST…THE UPPER LEVEL PORTION OF THE STORM WILL LAG
BEHIND…NOT CROSSING OUR REGION UNTIL WEDNESDAY EVENING. THIS WILL
KEEP OUR WEATHER SOMEWHAT UNSETTLED TONIGHT INTO WEDNESDAY. WEAK
ASCENT… CYCLONIC CIRCULATION AND LAKE ENHANCED MOISTURE WILL
CONSPIRE WITH STEEP LOW LEVEL LAPSE RATES TO PRODUCE LOTS OF CLOUDS
THROUGH WEDNESDAY…ALONG WITH LAKE ENHANCED/UPSLOPE SNOW
SHOWERS…MAINLY ACROSS THE ADIRONDACKS…BUT LATER AS THE FLOW GOES
FROM WESTERLY TO NORTHWESTERLY BY LATE WEDNESDAY…SNOW SHOWERS WILL
BE FOUND OVER THE GREENS/BERKSHIRES AND EVEN CATSKILLS. THE VALLEY
AREAS…PARTICULAR FROM ALBANY NORTHWARD WILL SEE LIMITED SNOW
SHOWER ACTIVITY…BUT EVEN HERE A BRIEF HEAVY SNOW SHOWER COULD COAT
THE GROUND IN SPOTS.

THERE IS POTENTIAL FOR MODERATE ACCUMULATIONS OF SNOW ACROSS THE
ADIRONDACKS TONIGHT THROUGH WEDNESDAY NIGHT…MAYBE EVEN THE
GREENS…WITH SPOTTY LIGHT ACCUMULATIONS POSSIBLE OVER THE CATSKILLS
AND BERKSHIRES. THIS DOES NOT APPEAR TO BE A PURE LAKE EFFECT…AT
LEAST THROUGH EARLY TONIGHT. LATER ON…AS THE UPPER AIR LOW MOVES
OFF THE NORTHEAST…THE FLOW WILL BECOME MORE NORTHWESTERLY AND THEN
MORE IN THE WAY OF LAKE EFFECT BANDS MIGHT WORK DOWN THE MOHAWK
VALLEY OR EVEN INTO THE CATSKILLS. UPSLOPE FLOW WILL BRING
ADDITIONAL SNOW SHOWERS ACROSS THE SOUTHERN GREENS AND
VERMONT.

THURSDAY WILL BE BRISK DAY WITH LOW PRESSURE OFF NOVA SCOTIA…AND
LARGE HIGH PRESSURE ANCHORED OVER HUDSON/S BAY…PRODUCING A FAIRLY
STEEP PRESSURE GRADIENT AND RESULT WIND. THERE STILL COULD BE SOME
LAKE EFFECT SNOW SHOWERS…BUT THE BRUNT OF THESE AT THIS TIME LOOK
TO REMAIN TO OUR WEST. UPSLOPE SNOWS HOWEVER…WILL CONTINUE ACROSS
MUCH OF OUR MOUNTAIN AREAS.

TEMPERATURES TONIGHT WILL DIP BACK INTO THE 20S (EXCEPT TEENS ACROSS
THE ADIRONDACKS). THEY WILL BE HARD PRESSED TO RISE MUCH ON
WEDNESDAY WITH THE CLOUDS AND ADDITIONAL COLD AIR ADVECTION. WE WENT
WITH A BLEND OF THE WARMER MAV/COLDER MET NUMBERS…LEANING A TAD
MORE WITH THE COLDER MET VALUES. FIGURE ON HIGH TEMPERATURES RANGING
FROM THE MID 30S IN THE MID HUDSON VALLEY/LOWER LITCHFIELD
COUNTY…TO AROUND 30 IN THE GREATER CAPITAL REGION…AND ONLY 20S
MOST OTHER HIGHER SPOTS. A WEST TO NORTHWEST WIND 10 TO 20 MPH WITH
GUSTS TO 30 MPH IN PLACES WILL MAKE IT FEEL A BIT COLDER. AT THIS
POINT…WE ARE NOT LOOKING FOR WIND CHILLS TO BE LOW ENOUGH TO ISSUE
ANY WIND CHILL ADVISORIES THROUGH WEDNESDAY.

WEDNESDAY NIGHT COULD BE A DIFFERENT STORY ACROSS THE ADIRONDACKS.
TEMPERATURES ARE FORECASTED TO TUMBLE TO THE SINGLE NUMBERS. WE ARE
FORECASTING WINDS TO REMAIN IN THE 10 TO 20 MPH RANGE…SO THAT WILL
PUT THE REGION CLOSE TO WIND CHILL ADVISORIES. THE REMAINDER OF THE
REGION WILL HAVE VALUES IN THE TEENS SO IT IS UNLIKELY ANY WIND
CHILL ADVISORIES WOULD BE NEEDED IN THESE REGIONS.

HIGH TEMPERATURES ON THURSDAY WILL ONCE AGAIN FALL SHORT OF LATE
FEBRUARY NORMALS…TOPPING OUT TO VALUES VERY SIMILAR TO WEDNESDAY.
IT WILL REMAIN BLUSTERY.

&&

.LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/…
THE COLD CYCLONIC NORTHWEST FLOW WILL BE LOOSENING ITS GRIP OVER THE
FORECAST AREA THURSDAY NIGHT AND HAVE KEPT THE FORECAST DRY. LOWS
ARE EXPECTED TO BE IN THE UPPER SINGLE NUMBERS AND TEENS.

FRIDAY INTO SATURDAY…A WEAK RIDGE WILL BUILD INTO THE REGION FROM
THE SOUTHWEST AHEAD OF OUR NEXT WEATHER SYSTEM. A LARGE AREA OF SFC
DIVERGENCE ASSOCIATED WITH A WEAK HIGH PRESSURE AREA WILL OVERSPREAD
THE REGION GOING INTO THE FIRST PART OF THE WEEKEND. IN ADDITION
MODELS SHOW A DEVELOPING LOW PRESSURE OVER THE UPPER MIDWEST MOVING
INTO THE WESTERN GREAT LAKES. HAVE KEPT POPS DRY ON FRIDAY SINCE
NONE OF THE MODELS INDICATE ANY PCPN REACHING THE ALBANY FORECAST
YET. POPS ARE FORECAST TO INCREASE FRIDAY NIGHT AND REACH 35 PERCENT
BY SATURDAY. ANY PCPN THAT DOES FALL DURING THE FRIDAY NIGHT AND
SATURDAY PERIOD WILL BE VERY LIGHT. HIGHS FRIDAY WILL BE 30 TO 40.
LOWS FRIDAY NIGHT IN THE UPPER TEENS AND 20S. HIGHS SATURDAY IN THE
30S AND LOWER 40S.

SATURDAY NIGHT INTO SUNDAY…MODELS CONTINUE TO SHOW A LOW
DEVELOPING OVER THE SOUTHEAST U.S. DURING THIS PERIOD AND MOVING
EAST-NORTHEAST OFF THE COAST. MOST MODEL RUNS INDICATE THAT ANY
SIGNIFICANT PCPN ASSOCIATED WITH THIS LOW WILL REMAIN SOUTH OF THE
FORECAST AREA…BUT OCCASIONAL RUNS (LIKE THE LATEST 00Z ECMWF RUN)
INDICATE SIGNIFICANT PCPN WILL COME FAR ENOUGH NORTH TO AFFECT THE
ALBANY FORECAST AREA. WITH LITTLE AGREEMENT BETWEEN THE MODELS…AND
FROM RUN TO RUN OF THE SAME MODELS…WILL ONLY RAISE POPS TO BETWEEN
35 AND 45 PERCENT SATURDAY NIGHT AND 25 TO 35 PERCENT SUNDAY. LOWS
SATURDAY NIGHT WILL BE IN THE 20S AND LOWER 30S. HIGHS SUNDAY IN THE
30S TO LOWER 40S…BUT WOULD BE CONSIDERABLY LOWER IF WIDESPREAD
PCPN WERE TO MOVE INTO THE REGION.

THE COASTAL LOW WILL BE OUT OF THE PICTURE SUNDAY NIGHT…BUT THE
REMNANTS OF THE LOW THAT WAS OVER THE GREAT LAKES WILL STILL BE
MOVING ACROSS THE REGION SUNDAY NIGHT…SO HAVE FORECAST SLIGHT
CHANCE POPS WITH LOWS IN THE 20S. HIGH PRESSURE WILL SLOWLY BUILD IN
FOR MONDAY WITH GRADUALLY CLEARING SKIES AND HIGHS IN THE 30S TO
LOWER 40S.

&&

.AVIATION /18Z TUESDAY THROUGH SUNDAY/…
LOW PRESSURE CONTINUES TO MOVE NORTH OF THE REGION THIS AFTERNOON
WITH A WARM FRONT MOVING ACROSS THE REGION. THE COLD FRONT WILL
MOVE THROUGH THIS EVENING WITH A SECONDARY LOW FORMING ACROSS NEW
ENGLAND.

VFR CONDITIONS WILL GIVE WAY TO MVFR/IFR CONDITIONS WITH RA/SN
TRANSITIONING TO ALL SNOW BY NIGHTFALL. THE MIXTURE OF RAIN AND
SNOW WILL REACH THE E-CNTRL NY AND WRN NEW ENGLAND TERMINALS BTWN
19Z-21Z. VSBYS WILL HAVE THE BEST CHC OF REACHING IFR LEVELS AT
KGFL AND KPSF…WITH CIGS FALLING INTO THE MVFR RANGE AT ALL THE
TAF SITES. THE PRECIPITATION SHOULD TRANSITION TO ALL SNOW SHORTLY
BEFORE 00Z/WED DUE TO COLUMN COOLING AND THE WET BULB EFFECT. THE
SNOW SHOULD TAPER OFF SHORTLY BEFORE MIDNIGHT…AND CIGS AND VSBYS
SHOULD INCREASE BACK TO VFR LEVELS BTWN 06Z-12Z/WED.

THE WINDS WILL CONTINUE TO BE LIGHT AND VARIABLE AT KPOU AND
KGFL…BUT S/SE WINDS OF 10-15 KTS WITH SOME GUSTS AT 20-25 KTS
WILL CONTINUE AT KALB/KPSF. THE WINDS WILL VEER TO THE W/SW AFTER
00Z/WED AT AROUND 10 KTS WITH SOME GUSTS AROUND 20 KTS AT KALB.
THE WINDS WILL INCREASE FROM THE W/NW AT 10-15 KTS WITH SOME GUSTS
CLOSE TO 25 KTS AT KALB AND KPSF AFTER 12Z/WED.

OUTLOOK…
WED…MAINLY VFR. SLIGHT CHC/CHC MVFR -SHSNS NORTH OF KALB.
BLUSTERY.
THU-FRI…VFR. NO SIG WX.
FRI NIGHT-SAT NIGHT…VFR/MVFR. CHC -SN.
SUN…VFR/MVFR…CHC -RA/-SN.

&&

.HYDROLOGY…
NO HYDROLOGY PROBLEMS ARE EXPECTED OVER THE NEXT FEW DAYS. EVEN
THOUGH TEMPERATURES WILL BRIEFLY BE ABOVE FREEZING TODAY…IT WILL
NOT BE A LONG ENOUGH DURATION TO PRODUCE ANY ADDITIONAL MELTING OF
SNOW OR ICE.

PRECIPITATION TODAY LOOKS LIGHT…IN THE TENTH TO A QUARTER INCH
RANGE. SOME OF THAT COULD BE IN THE FORM OF SNOW…MAINLY ACROSS THE
ADIRONDACKS…WITH ONLY LIGHT ACCUMULATIONS. ELSEWHERE IT WILL BE
RAIN…POSSIBLY MIXED WITH A LITTLE SLEET OR A FEW WET SNOW FLAKES.
PRECIPITATION WILL NOT AFFECT ANY WATERSHEDS.

LAKE ENHANCED/UPSLOPE SNOWS COULD PRODUCE MINOR TO MODERATE SNOW
ACCUMULATIONS NAMELY IN THE ADIRONDACKS AND OTHER MOUNTAIN AREAS ON
WEDNESDAY INTO THURSDAY.

THEN…THE NEXT SYNOPTIC SYSTEM THAT COULD IMPACT OUR REGION WILL BE
EITHER RAIN OR SNOW FOR NEXT WEEKEND.

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…HWJIV/NAS
NEAR TERM…HWJIV/NAS
SHORT TERM…HWJIV
LONG TERM…GJM
AVIATION…WASULA
HYDROLOGY…HWJIV/NAS

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