February 16, 2012 Forecast Discussion

00
FXUS61 KALY 170257
AFDALY

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ALBANY NY
950 PM EST THU FEB 16 2012

.SYNOPSIS…
A FAST MOVING FRONTAL BOUNDARY WILL BRING A LITTLE SPOTTY
LIGHT NUISANCE PRECIPITATION TO THE REGION THIS OVERNIGHT. ANY
ADDITIONAL SNOW ACROSS THE HIGHER ELEVATIONS WILL BE AN INCH OR LESS
WITH NO ACCUMULATIONS EXPECTED IN THE VALLEYS. DRIER AIR WILL MOVE
TOMORROW WITH MOST OF THE REGION SEEING A RETURN TO A LITTLE
SUNSHINE. SOME SNOW SHOWERS WILL REDEVELOP ACROSS THE HIGHER TERRAIN
AROUND ALBANY LATER IN THE DAY.

&&

.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/…
AS OF 950 PM…MOST OF THE PRECIPITATION HAS ENDED FROM THE HUDSON
VALLEY ON WESTWARD ACROSS THE REGION. THERE WERE STILL SOME
SCATTERED LIGHT RAIN OR SNOW SHOWERS IN THIS AREAS…MORE NUMEROUS
STILL TO THE EAST OF THE HUDSON VALLEY.

OUR REGION REMAINS STUCK UNDERNEATH LOW LEVEL MOISTURE AND THEREFORE
WE CAN STILL EXPECT VERY LIGHT SPOTTY SHOWERS OF RAIN OR SNOW
OVERNIGHT…EXCEPT NUMEROUS SHOWERS BECOME SCATTERED TO THE EAST OF
ALBANY. ADDITIONAL QPF WILL BE A FEW HUNDREDTHS OF AN INCH IF THAT.
ADDITIONAL SNOW ACCUMULATIONS WILL BE CONFINED TO AREAS OVER 1000
FEET ABOVE SEA LEVEL…A DUSTING TO NO MORE THAN AN LOCALLY AN
INCH.

TEMPERATURES WILL REMAIN NEARLY STEADY OVERNIGHT…IN THE LOWER TO
MID 30S…EXCEPT SOME UPPER 20S ACROSS THE ADIRONDACKS. THE WIND
WILL BE LIGHT OUT OF THE SOUTH OR SOUTHWEST…BECOMING WESTERLY BY
DAYBREAK.

&&

.SHORT TERM /6 AM FRIDAY MORNING THROUGH SATURDAY NIGHT/…
THE AFOREMENTIONED DRY SLOT MOVES ACROSS THE CWA DURING FRIDAY
MORNING WHERE AMPLE BREAKS IN THE CLOUDS ARE EXPECTED. WIND
TRAJECTORIES BECOME WESTERLY AS 850MB TEMPS DROP BACK TOWARD -10C.
THIS WOULD SET THE STAGE FOR A MARGINAL LAKE EFFECT EVENT DOWNWIND
OF LAKE ONTARIO AS INVERSION HEIGHTS ARE FORECAST TO BE BETWEEN
5-6K FEET /C0COULD BE A LITTLE HIGHER AS CYCLONIC FLOW INCREASES
OVER THE LAKE/. LOW LEVEL CONVERGENT SIGNALS REMAIN SUB-PAR AS
BANDS DO NOT LOOK TO BE TOO ORGANIZED. AT THIS TIME…WE WILL
PLACE 1-3 INCHES FOR PORTIONS OF HERKIMER COUNTY AND CLOSELY
MONITOR TRENDS.

OTHERWISE…MIXING LAYER HEIGHTS AND MOMENTUM TRANSFER SUGGESTS
WINDS WILL OCCASIONALLY GUST OVER 20KTS WITH SOME POTENTIAL
FUNNELING DOWN THE MOHAWK WITH GUSTS TO 30KTS IN THE CAPITAL
REGION. BASED ON CURRENT UPSTREAM TEMPERATURES IN THE WAKE OF THE
FROPA…WE WILL FORECAST HIGHS IN THE VALLEYS INTO THE 40S WITH
30S FOR THE WESTERN MOHAWK VALLEY AND HIGHER TERRAIN ABOVE 1000
FEET.

A SHORT WAVE RIDGE AXIS QUICKLY MOVES ACROSS NY STATE OVERNIGHT
FRIDAY WHICH WILL LOWER THE INVERSION HEIGHTS AND DIMINISH LAKE
EFFECT. STILL COULD SEE SOME CLOUD COVER ACROSS THE TERRAIN AS
THIS MOISTURE BECOMES TRAPPED UNDER THE SUBSIDENCE INVERSION.

LOOKING UPSTREAM…NCEP MODEL SUITE AND INTERNATIONAL GUIDANCE
SUGGESTS A FAST MOVING CLIPPER SYSTEM DURING SATURDAY AND SATURDAY
EVENING. THIS WAVE WILL WEAKEN AS IT BECOMES ENTRAINED WITHIN THE
CONFLUENT FLOW. NEVERTHELESS…SEEMS A BAND OF PRECIP WILL MOVE
ACROSS THE REGION. AT THIS TIME…THERMAL PROFILES SUGGEST MAINLY
SNOW YET BOUNDARY LAYER TEMPS COULD BE A LITTLE WARMER FOR A
RAIN/SNOW MIXTURE WITH CURRENT QPF FIELDS AROUND ONE TENTH OF AN
INCH.

THIS SYSTEM QUICKLY DEPARTS TOWARD MIDNIGHT WITH IMPROVING
CONDITIONS AS HIGH PRESSURE RETURNS AND NEAR SEASONABLE
TEMPERATURES.

&&

.LONG TERM /SUNDAY THROUGH THURSDAY/…
THE NORTH ATLANTIC OSCILLATION (NAO) LOOKS TO REMAIN WEAKLY
POSITIVE THROUGHOUT THE EXTENDED PERIOD. THIS HAS BEEN THE
PREVAILING PATTERN ALL WINTER LONG AND AGAIN WHEN THE NAO IS
POSITIVE…THIS FEATURES A PERSISTENT LOW PRESSURE ANCHORED NEAR
ICELAND AND HIGH PRESSURE NEAR THE AZORES…WHICH WILL BE THE CASE
GOING INTO THE EXTENDED PERIOD. IN THIS MODE…THE POLAR JETSTREAM
USUALLY IS DISPLACED FURTHER NORTH THAN NORMAL AND
ZONAL…ALLOWING FOR LITTLE OR NO PHASING WITH THE SOUTHERN
JETSTREAM AND THEREFORE LIMITED OPPORTUNITY FOR COASTAL STORMS (IE
NOR`EASTERS). ALSO…THIS PATTERN KEEPS MOST OF THE REALLY ARCTIC
AIR TO OUR NORTH.

WE WILL START THE PERIOD WITH A STORM IN THE SOUTHERN STREAM WORKING
INTO THE MID ATLANTIC REGION SUNDAY. A FEW PAST MODEL RUNS OF THE
GFS…AND ENSEMBLE MEMBERS OF THE GFS…SUGGESTED THIS STORM WOULD
PHASE WITH THE NORTHERN JETSTREAM AND PRODUCE A SIGNIFICANT
SNOWSTORM. HOWEVER…THIS IS LOOKING LESS AND LESS LIKELY TO BE THE
CASE…AND MOST…IF NOT ALL MODEL GUIDANCE (INCLUDING THE MOST
RECENT 12GFS) HAS THIS SYSTEM SLIDING OFF TO OUR SOUTH…POSSIBLY
GRAZING OUR EXTREME SOUTHERN AREAS WITH A LITTLE SNOW OR RAIN SUNDAY
BUT EVEN HERE…THE ODDS FAVOR IT EVEN MISSING THESE AREAS. WE WILL
KEEP SLIGHT CHANCES IN ON SUNDAY INTO SUNDAY EVENING BUT THAT AS FAR
AS IT GOES.

AS THIS STORM SLIDES PRESUMABLY SLIPS TO OUR BY MONDAY…HIGH
PRESSURE BUILDS INTO THE REGION. MONDAY LOOKS SEASONABLY CHILLY AND
DRY WITH A GOOD DEAL OF SUNSHINE. AS THIS HIGH SLIDES TO OUR
EAST…TEMPERATURES WILL MODERATE ONCE MORE TO ABOVE NORMAL LEVELS
WHERE THEY HAVE BEEN MOST OF THE WINTER.

BY WEDNESDAY…A WEAK SYSTEM LOOKS TO MOVE ACROSS THE NORTHERN TIER
WITH POLAR JETSTREAM AND SHOULD BRING US A LITTLE RAIN (POSSIBLY
MIXED WITH WINTRY PRECIPITATION). FROM THIS VANTAGE POINT…THIS
SYSTEM LOOKS TO BRING ONLY LIGHT AMOUNTS OF QPF AS IT TOO WILL BE
MOVING QUICKLY IN THE PROGRESSIVE FLOW PATTERN WITH LITTLE
OPPORTUNITY TO REALLY STRENGTHEN.

ANOTHER COLD FRONT APPROACHES THURSDAY AND PERHAPS ANOTHER ONE FOR
FRIDAY…KEEP OUR WEATHER SOMEWHAT UNSETTLED WITH SLIGHT CHANCES OF
SHOWERS. HOWEVER…MUCH OF THIS TIME WILL LIKELY BE DRY TEMPERATURES
REMAINING A BIT ABOVE NORMAL.

&&

.AVIATION /03Z FRIDAY THROUGH TUESDAY/…

SO FAR…IFR CONDITIONS (LOW CIGS) PERSISTED AT KGFL AND
KALB…WHILE KPOU HAS HAD LOW MVFR CIGS (UNDER 2000 FEET BUT OVER
1000 FEET).

DON`T EXPECT A WHOLE LOT TO CHANGE OVERNIGHT ALTHOUGH CIGS AT KALB
SHOULD EVENTUALLY LIFT TO LOW MVFR. AT KPOU…STILL BELIEVE A
SLIGHTLY BETTER THAN 50/50 THAT AT LEAST SOME OF THE TIME…CIGS
WILL DIP TO JUST UNDER 1000 FEET BUT PRIMARILY IN THE LOW MVFR
RANGE.

AFTER MIDNIGHT…HAVE HELD CIGS BELOW 2000 FEET AS IT LOOKS AS IF
THEY WILL PERSIST TO BE RATHER LOW. AS A COLD FRONT APPROACHES NEAR
SUNRISE…MIXING SHOULD LIFT CIGS BACK ACROSS THE MVFR/VFR THRESHOLD
WITH GOOD VISIBILITIES. ANY LAKE EFFECT SNOW SHOWERS SHOULD REMAIN
AWAY FROM THE TAFS ON FRIDAY AS VFR CONDITIONS PREVAIL AT ALL THE
TAF SITES.

THE WIND…WHICH WILL BE LIGHT OUT OF THE SOUTH TONIGHT…WILL TURN
WESTERLY AND INCREASE TO AROUND 10KTS…BECOMING GUSTY AT BOTH KPOU
AND KALB BY 18Z…WITH GUSTS TO ABOUT 20KTS.

OUTLOOK…
FRI NITE-SAT…VFR…NO SIG WX.
SAT NGT…VFR. CHC MVFR WITH -SW POSS MIX WITH -RA.
SUN…VFR…SLIGHT CHC MVFR IN -SN.
MON-TUE…VFR…NO SIG WX.

&&

.HYDROLOGY…
NO HYDRO PROBLEMS ARE EXPECTED OVER THE NEXT SEVERAL DAYS. SOME
GAGES WILL CONTINUE TO HAVE ICE EFFECTS NORTH OF THE MOHAWK RIVER
VALLEY IN THE ALBANY HYDRO SERVICE AREA.

A LOW PRESSURE SYSTEM AND ITS ASSOCIATED COLD FRONT WILL BRING SOME
RAIN AND/OR SNOW TO THE REGION FROM THIS AFTERNOON THROUGH TONIGHT.
QPF AMOUNTS GENERALLY EXPECTED TO BE AROUND ONE-TWO TENTHS OF AN
INCH TO ONE THIRD OF AN INCH ACROSS THE HSA.

SOME LAKE ENHANCED OR UPSLOPE SNOWFALL IS POSSIBLE FOR THE WESTERN
ADIRONDACKS FRIDAY INTO SATURDAY WITH LIGHT ACCUMULATIONS EXPECTED.

THE WINTER SPRING FLOOD POTENTIAL OUTLOOK HAS BEEN ISSUED FOR
EASTERN NEW YORK AND WESTERN NEW ENGLAND. PLEASE REFER TO
ALBESFALY /FGUS71 KALY/ FOR FURTHER DETAILS.

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/BGM
NEAR TERM…HWJIV/BGM
SHORT TERM…BGM
LONG TERM…HWJIV
AVIATION…HWJIV
HYDROLOGY…BGM

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