February 13, 2012 Forecast Discussion

000
FXUS61 KALY 131136
AFDALY

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ALBANY NY
636 AM EST MON FEB 13 2012

.SYNOPSIS…
LAKE EFFECT SNOW WILL CONTINUE TO AFFECT AREAS EAST OF LAKE ONTARIO
INTO EARLY THIS AFTERNOON. HOWEVER…AS MILDER AIR AND HIGH PRESSURE
BUILDS IN FROM THE SOUTHWEST…THE LAKE EFFECT ACTIVITY WILL SUBSIDE
THIS AFTERNOON. A WEAK DISTURBANCE WILL APPROACH THE REGION FROM THE
WEST BY LATE TUESDAY AFTERNOON…WITH A CHANCE OF SNOW OR MIXED
PRECIPITATION TUESDAY NIGHT INTO WEDNESDAY.

&&

.NEAR TERM /THROUGH TODAY/…
AS OF 615 AM…KTYX RADAR SHOWS THE LAKE ONTARIO SNOW BAND
WEAKENING. NOT CONFIDENT ENOUGH TO CANCEL THE LAKE EFFECT SNOW
ADVISORY YET…BUT IF THE TREND CONTINUES…THE ADVISORY CAN LIKELY
BE CANCELLED WITH THE NEXT UPDATE. TEMPS HAVE BEGUN TO SLOWLY RISE
ACROSS THE REGION AND HOURLY TEMPS GRIDS WERE MUCH TOO COLD. HAVE
ADJUSTED THE HOURLY TEMP GRIDS TO TAKE INTO ACCOUNT CURRENT
CONDITIONS.

PREVIOUS DISCUSSION
AS OF 400 AM…THE LAKE EFFECT BAND HAD SHIFTED NORTH AND OUT OF THE
SOUTHERN HERKIMER REGION. WITH THE BAND CURRENTLY SHOWING LITTLE OR
NO MOVEMENT OVER THE PAST 2 TO 3 HOURS AND NOT EXPECTED TO RETURN
SOUTH…HAVE CANCELLED THE LAKE EFFECT SNOW ADVISORY FOR SOUTHERN
HERKIMER COUNTY. BUT DID ISSUE AN ADVISORY FOR NORTHERN HERKIMER AND
HAMILTON COUNTIES. LOCAL CSTAR RESEARCH TOOL FOR DETERMINING THE
INLAND EXTENT OF LAKE SNOW BANDS INDICATES THAT THE BAND WILL EASILY
REACH INTO WESTERN HAMILTON COUNTY AS WELL AS NORTHERN HERKIMER
COUNTY THIS MORNING. THE REST OF THE REGION WILL ALSO HAVE SCATTERED
TO ISOLATED SNOW SHOWERS THIS MORNING.

AS HIGH PRESSURE BUILDS IN AND THE INVERSION LOWERS…EXPECT ALL
SNOW SHOWER ACTIVITY…INCLUDING THE LAKE EFFECT SNOW…TO DIMINISH
THIS AFTERNOON. GENERALLY CLOUDY SKIES THIS MORNING WILL BECOME
MOSTLY CLOUDY TO PARTLY SUNNY THIS AFTERNOON.

WILL STILL HAVE A GUSTY WIND TODAY…BUT IT WILL BE MILDER THAN
SUNDAY. HIGHS TODAY WILL BE IN THE UPPER 20S TO NEAR 40.

&&

.SHORT TERM /TONIGHT THROUGH WEDNESDAY/…
— Changed Discussion —
HIGH PRESSURE WILL BRIEFLY BUILD INTO THE REGION TONIGHT…THEN A
UPPER LEVEL TROF CURRENTLY OVER THE ROCKIES…WILL EJECT A SHORT
WAVE TROF EASTWARD…WHICH WILL EVENTUALLY AFFECT OUR REGION TUESDAY
NIGHT AND WEDNESDAY. IT WILL BE QUITE WEAK WHEN IT REACHES OUR
REGION AND MODELS FORECAST VERY LITTLE QPF. HAVE FORECAST POPS NO
HIGHER THAN ABOUT 40 PERCENT DURING THIS PERIOD. MAINLY SNOW SHOWERS
EXPECTED…BUT DURING THE WARMEST PART OF THE DAY…THE PCPN IS
LIKELY TO FALL AS RAIN SHOWERS OVER MOST VALLEY LOCATIONS AND ACROSS
MUCH OF THE SOUTHERN PART OF THE FORECAST AREA.

LOWS TONIGHT WILL BE IN THE TEENS TO LOWER 20S. HIGHS TUESDAY IN THE
30S TO LOWER 40S. LOWS TUESDAY NIGHT IN THE UPPER TEENS AND
20S…AND THE HIGHS WEDNESDAY IN THE UPPER 30S TO MID 40S.
— End Changed Discussion —

&&

.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/…
MEDIUM RANGE GUIDANCE HAS COME INTO BETTER AGREEMENT WITH REGARDS TO
A STORM SYSTEM APPROACHING FROM THE CENTRAL PLAINS STATES AND GREAT
LAKES FOR THURSDAY INTO THURSDAY NIGHT. AS HAS BEEN THE CASE WITH
MANY OF THE STORMS WE HAVE EXPERIENCED THIS WINTER…THE PRIMARY
SURFACE LOW CENTER IS FORECAST TO TRACK TO THE NORTH OF LAKE ONTARIO
AND THE ST LAWRENCE RIVER VALLEY. THIS TYPE OF STORM TRACK WILL
LIKELY YIELD MAINLY RAIN IN THE VALLEYS…WITH SOME SNOW ACROSS THE
HIGHER TERRAIN. MOST SOURCES OF GUIDANCE STILL SHOWING SECONDARY
CYCLOGENESIS OCCURRING OFF THE DELMARVA THURSDAY NIGHT INTO FRIDAY
MORNING…ALTHOUGH THIS APPEARS TO HAPPEN TOO LATE TO GIVE US ANY
APPRECIABLE PRECIP ONCE THE PRIMARY LOW PASSES TO OUR NORTH. THERE
COULD BE ENOUGH COLD AIR WRAPPING AROUND TO RESULT IN SOME LINGERING
SNOW SHOWERS FOR ALL ELEVATIONS AS THE STORM SYSTEM DEPARTS BUT THIS
IS IN QUESTION.

IN GENERAL…USED A BLEND OF RAIN/SNOW FOR PTYPE BASED ON DIURNAL
TEMPS AND ELEVATION DEPENDENCY. SYSTEM IS GOING TO BE A
FAST-MOVER…SO NO SIGNIFICANT QPF WITH AROUND A THIRD TO THREE
QUARTERS OF AN INCH EXPECTED AT THIS TIME. MAIN TIME FRAME WHERE
PRECIP IS MOST LIKELY APPEARS TO BE FROM LATE THURSDAY THROUGH
THURSDAY NIGHT BASED ON LATEST GUIDANCE. SOME LINGERING UPSLOPE/LAKE
ENHANCED SNOW SHOWERS WILL BE POSSIBLE FRIDAY INTO FRIDAY NIGHT WITH
TEMPS COOLING BACK TO NEAR SEASONAL READINGS.

MAINLY A DRY NORTHWEST FLOW IN STORE FOR THE WEEKEND…WITH PERHAPS
SOME LAKE EFFECT SNOW SHOWERS DEPENDING ON MIXED LAYER DEPTH AND
TRAJECTORIES. OTHERWISE SEASONABLE TEMPS AND GENERALLY TRANQUIL
WEATHER EXPECTED TO RETURN.

&&

.AVIATION /12Z MONDAY THROUGH FRIDAY/…
— Changed Discussion —
A WEST-NORTHWEST FLOW REGIME WILL CONTINUE THROUGH TODAY. FLURRIES
WILL DIMINISH THROUGH THE MORNING…ALTHOUGH SOME WILL LINGER FROM
KALB-KGFL. MAINLY VFR CONDITIONS SHOULD PREVAIL WITH CLOUDS
GRADUALLY SCOURING OUT AS DRIER AND WARMER AIR ALOFT MOVES IN.

WINDS WILL INITIALLY BE SOUTHWEST AROUND 7 TO 10 KT…BECOMING
WESTERLY LATE THIS MORNING AROUND 12 TO 17 KT WITHS GUSTS BETWEEN 20
TO 30 KT POSSIBLE ESPECIALLY AT KALB WHERE CHANNELING DOWN THE
MOHAWK VALLEY WILL ENHANCE WIND SPEEDS. WINDS WILL DIMINISH TO
AROUND 3-7 KT DURING THE EVENING.

OUTLOOK…
TUE…VFR…NO SIG WX.
TUE NIGHT-WED…MAINLY VFR. MVFR POSSIBLE WITH CHC -SHRA/-SHSN.
WED NIGHT-THU AM…VFR…NO SIG WX.
THU PM-FRI…MAINLY MVFR…-RA/-SN LIKELY WITH POSSIBLE IFR.
— End Changed Discussion —

&&

.HYDROLOGY…
NO HYDRO PROBLEMS ARE EXPECTED OVER THE NEXT SEVERAL DAYS. SOME
GAGES WILL CONTINUE TO HAVE ICE EFFECTS ACROSS THE NORTHERN TIER
OF THE ALBANY HYDRO SERVICE AREA /HSA/.

SOME LAKE EFFECT SNOWFALL WILL IMPACT THE REGION INTO EARLY THIS
AFTERNOON WITH LIQUID EQUIVALENT AMOUNTS OF A FEW HUNDREDTHS TO
AROUND A TENTH OF AN INCH. TEMPERATURES WILL MODERATE TO ABOVE
NORMAL BY THE MIDDLE OF THE WEEK.

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…LAKE EFFECT SNOW ADVISORY UNTIL 1 PM EST MONDAY FOR NYZ032-033.
MA…NONE.
VT…NONE.

&&

$$
SYNOPSIS…GJM
NEAR TERM…GJM
SHORT TERM…GJM
LONG TERM…JPV
AVIATION…JPV
HYDROLOGY…GJM

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