February 11, 2015 Forecast Discussion

000
FXUS61 KALY 120049
AFDALY

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ALBANY NY
749 PM EST WED FEB 11 2015

.SYNOPSIS…
A FAST MOVING CLIPPER TYPE LOW PRESSURE SYSTEM WILL APPROACH FROM
SOUTHERN ONTARIO AND THE GREAT LAKES REGION TONIGHT…BRINGING
SNOW SHOWERS TO THE REGION INTO THURSDAY. ANOTHER FRIGID AIR MASS
WILL THEN BUILD BACK INTO THE REGION THURSDAY NIGHT INTO THE
UPCOMING WEEKEND…WITH THE POSSIBILITY OF SOME SNOW OR SNOW
SHOWERS ON SATURDAY WITH ANOTHER CLIPPER SYSTEM. THE COMBINATION
OF WIND AND VERY LOW TEMPERATURES WILL YIELD TO POTENTIALLY
DANGEROUS WIND CHILLS THURSDAY NIGHT…ESPECIALLY OVER THE HIGHER
TERRAIN TO THE WEST OF THE HUDSON VALLEY.

&&

.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/…
RELATIVELY BENIGN AND ONLY SEASONABLY COLD WEATHER ACROSS THE
REGION. TEMPERATURES WERE GENERALLY IN THE 20S REGIONWIDE WITH A
PARTLY CLOUDY SKY. THE WIND WAS RELATIVELY LIGHT.

SOME LIGHT SNOW SHOWERS WERE ADVANCING AHEAD OF A CLIPPER SYSTEM
WHICH WAS WORKING ACROSS THE NORTHERN GREAT LAKES. WEAK WARM
ADVECTION/ISENTROPIC LIFT AND VORITICITY ADVECTION WAS CONTRIBUTING
TO THE LIGHT SNOW. CLOUDS WILL INCREASE THIS EVENING FROM WEST TO
EAST. THE SNOW WILL WORK INTO THE ADIRONDACKS AFTER MIDNIGHT…AND
THE REMAINDER OF OF THE REGION OVERNIGHT INTO EARLY THURSDAY. THE
BEST CHANCE FOR ACCUMULATING SNOW WILL BE OVER THE HIGHER
TERRAIN…WHERE AN INCH OR SO OF SNOW WILL ACCUMULATE WITH A DUSTING
OR NOTHING IN THE VALLEYS OVERNIGHT.

TEMPERATURES WILL NOT BE AS COLD TONIGHT…GENERALLY IN THE TEENS
ALBANY SOUTHWARD…SINGLE NUMBERS NORTH. THE LOWS WILL LIKELY
OCCUR BEFORE MIDNIGHT…THEN REMAIN STEADY OR RISE A LITTLE
TOWARD DAYBREAK.

&&

.SHORT TERM /6 AM THURSDAY MORNING THROUGH SATURDAY/…
WIND CHILL WATCH POSTED FOR THE CATSKILLS AND ADIRONDACKS (INCLUDING
ALL OF THE MOHAWK VALLEY) FROM THURSDAY MIDNIGHT TO FRIDAY NOON.

ON THURSDAY…THE AFOREMENTIONED CLIPPER SYSTEM WILL TRANSLATE EAST
INTO NORTHERN NYS AND NEW ENGLAND. IT STILL LOOKS AS IF A SECONDARY
LOW WILL DEVELOP SOUTH OF LONG ISLAND. MOISTURE WILL BE LIMITED
WITH THIS SYSTEM…AND THE ISENTROPIC LIFT WILL BE FAIRLY WEAK
ACROSS OUR REGION. ADDITIONAL ACCUMULATING SNOW WILL BE LIKELY
ACROSS THE HIGHER TERRAIN…ESPECIALLY TO THE EAST AND SOUTHEAST OF
THE HUDSON VALLEY WERE THE SHIELD OF SNOW ASSOCIATED WITH THE
SECONDARY LOW PRESSURE MIGHT BRUSH.

MEANWHILE…THE CLIPPER WILL DRAG AN ARCTIC COLD FRONT THROUGH THE
REGION FROM WEST TO EAST MIDDAY INTO THE AFTERNOON HOURS. IT WILL
TURN MUCH COLDER BEHIND THE FRONT…AND WINDIER TOO. WINDS COULD
GUST UP TO 35 MPH AT TIMES.

OVERALL LOOK FOR UP TO AN INCH IN MOST VALLEY AREAS ON
THURSDAY…CLOSER TO 2 INCHES NEAR SARATOGA…2-3 HIGHER TERRAIN AND
LITCHFIELD COUNTY.

HIGH TEMPERATURES ON THURSDAY WILL BE AROUND 30 IN MOST VALLEY
AREAS…20S HIGHER TERRAIN. TEMPERATURES WILL DROP INTO THE TEENS
AND LOWER IN OUR NORTHWESTERN ZONES BY LATE IN THE DAY WITH WIND
CHILLS DROPPING PRECIPITOUSLY TO BELOW ZERO.

THURSDAY NIGHT ANOTHER ROUND A VERY COLD ARCTIC AIR WILL BE POURING
IN ON GUSTY NORTHWEST WINDS. ACTUAL AIR TEMPERATURES WILL DROP TO
AROUND ZERO IN VALLEY AREAS…BUT 5 TO 20 BELOW BELOW ZERO ACROSS
THE HIGHER ELEVATIONS…WITH THE LOWEST READINGS IN THE ADIRONDACKS.
THE COMBINATION OF PERSISTENT 10 TO 20 MPH WINDS AND THE VERY LOW
TEMPERATURES COULD DRIVE WIND CHILL TEMPERATURES TO AS LOW AS 25 T0
40 BELOW ZERO ACROSS THE HIGHER TERRAIN TO THE WEST OF THE HUDSON
VALLEY. VALLEY AREAS AND ELEVATED TERRAIN TO THE EAST OF THE HUDSON
VALLEY WILL LIKELY NOT REACH WIND CHILL WARNING LEVELS…BUT COULD
REACH ADVISORY LEVELS SO NO ACTION YET ON THESE AREAS…EXCEPT IN
OUR HAZARDOUS WEATHER OUTLOOK.

SNOW SHOWERS ON THURSDAY NIGHT WILL LINGER MAINLY TO THE EAST OF THE
HUDSON VALLEY WHERE ADDITIONAL INCH OR SO OF SNOW COULD FALL.
OTHERWISE IT WILL BE DRY WITH GRADUAL CLEARING.

FRIDAY WILL START OUT EXTREMELY COLD AND END UP NOT MUCH BETTER.
DESPITE A GOOD DEAL OF PROJECTED SUNSHINE…HIGH READINGS ON FRIDAY
WILL REMAIN AT OR BELOW ZERO ACROSS MOST OF THE ELEVATED
TERRAIN…SINGLE NUMBERS IN THE VALLEYS…EXCEPT 10 TO 15 TO THE LEE
OF THE CATSKILLS…INCLUDING THE MID HUDSON VALLEY AND
LOWER LITCHFIELD COUNTY.

FRIDAY NIGHT…OVERNIGHT LOWS WILL BE TRICKY TO FORECAST. HIGH
PRESSURE WILL CREST OVER THE REGION SO THE WIND WILL BECOME LIGHT OR
CALM. CLOUDS WILL EVENTUALLY INCREASE AHEAD OF THE NEXT STRONGER
LOOKING CLIPPER. DEPENDING ON HOW FAST THESE CLOUDS COME IN WILL
DETERMINE HOW LOW TEMPERATURES WILL GO. THE LONGER THE CLOUDS TAKE
TO MOVE IN THE LOWER TEMPERATURES WILL GO. FOR NOW…LEANED ON THE
COLDER SIDE OF GUIDANCE (SLOWER ARRIVAL OF CLOUDS) WHICH WILL MEAN
LOWS SHOULD DROP TO 5 TO 10 BELOW ZERO ALBANY SOUTHWARD…10 TO 25
BELOW ZERO OUTLYING AREAS…AND ALL REGIONS NORTH OF THE CAPITAL
REGION.

SATURDAY…THE NEXT CLIPPER ARRIVES AND ONCE AGAIN…IT LOOKS AS IF
ENERGY FROM THE SYSTEM WILL TRANSFER TO ANOTHER STORM SOUTHEAST OF
LONG ISLAND. IF THE SECONDARY LOW FORMS MORE QUICKLY…STEADY SNOW
COULD IMPACT MUCH OF OUR REGION…BUT RIGHT NOW OUR THINKING IS THAT
ANY STEADY SNOW WILL LIMITED TO ADJACENT WESTERN NEW ENGLAND WITH
LIGHTER SNOW SHOWERS ACROSS THE REMAINDER OF THE REGION. EITHER
WAY…IT WILL TURN WINDY ONCE AGAIN WITH ANOTHER INCREDIBLY FRIGID
AIRMASS BUILDING IN BY SUNDAY NIGHT.

&&

.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/…
BITTERLY COLD WITH DANGEROUSLY COLD WIND CHILLS THROUGH THE
HOLIDAY WEEKEND WITH TEMPERATURES EXPECTED TO MODERATE AS WE HEAD
INTO THE MIDDLE OF THE WEEK…BUT REMAIN BELOW NORMAL. AS FOR
SNOWFALL…ANOTHER ROUND IS EXPECTED SATURDAY NIGHT WITH THE NEXT
CHANCES COMING MID WEEK.

WIND CHILL HEALDINES WILL BE NEEDED FROM SATURDAY NIGHT THROUGH MONDAY MORNING.
THE COLDEST TIME WILL BE SUNDAY NIGHT INTO MONDAY WHEN LOW TEMPERATURES ARE
EXPECTED TO BE GENERALLY FROM AROUND 10 TO 20 DEGREES BELOW ZERO. WHEN YOU ADD
THE AFFECTS OF THE WIND…WIND CHILL VAULES OF 25 TO 45 DEGREES BELOW ZERO ARE
ANTICIPATED.

A VIGOROUS SHORT WAVE WILL DIVE SOUTHEAST OUT OF CANADA SATURDAY DEEPENING
THE LONGWAVE TROUGH OVER THE EASTERN UNITED STATES AND CUTTING OFF AN UPPER LOW.
THIS WILL RESULT IN A LOW PRESSURE SYSTEM TRACKING ACROSS THE REGION SATURDAY TO
STRENGTHEN OFF THE NEW ENGLAND COAST SATURDAY NIGHT INTO SUNDAY. A WIDESPREAD
SNOWFALL IS EXPECTED. AT THIS TIME…IT APPEARS A LIGHT TO MODERATE SNOWFALL
SHOULD OCCUR.

IN THE WAKE OF THIS SYSTEM AS ANOTHER SHOT OF BITTERLY COLD AIR WILL BE USHERED
IN…SOME OF THE COLDEST AIR OF THE WINTER. TO MAKE MATTERS WORSE WE WILL HAVE
A TIGHT PRESSURE GRADIENT ACROSS THE REGION BETWEEN DEPARTING DEEPENING LOW
PRESSURE SYSTEM AND AN ADVANCING RIDGE. THE COMBINATION OF THE BITTERLY COLD
AIRMASS AND WINDS WILL RESULT IN DANGEROUSLY COLD TO LIFE
THREATENING WIND CHILLS.

THE RIDGE IS EXPECTED TO QUICKLY MOVE ACROSS THE REGION MONDAY NIGHT AND TUESDAY
RESULTING IN FAIR WEATHER WITH MODERATING TEMPERATURES…BUT STILL BELOW NORMAL.

ANOTHER LOW PRESSURE SYSTEM APPROACHES FROM THE DEEP SOUTH BRINGING WARM
ADVECTION PRECIPITATION TO THE REGION FOR THE MID WEEK PERIOD.
TUESDAY. HIGHS IN THE TEENS AND 20S TUESDAY AND WEDNESDAY.

&&

.AVIATION /01Z THURSDAY THROUGH MONDAY/…
A CLIPPER LOW APPROACHING FROM WEST WILL BRING LIGHT SNOW TO THE
AREA. VFR CONDITIONS ARE EXPECTED THROUGH THE EVENING WITH MVFR
CONDITIONS DEVELOPING AS THE CLOUDS THICKEN AND LOWER OVERNIGHT.
LIGHT SNOW WILL BREAK OUT IN THE WARM ADVECTION AHEAD OF THE
CLIPPER AROUND DAYBREAK AND IS EXPECTED TO LAST INTO THE EARLY
AFTERNOON. EXPECTING MAINLY MVFR BUT IFR CONDITIONS ARE POSSIBLE
BUT DO NOT HAVE HIGH CONFIDENCE TO IMCLUDE IN THE FORECAST AT THIS
TIME. LIGHT WINDS WILL SHIFT TO WEST WITH THE PASSAGE OF TEH
CLIPPER/COLD FRONT WITH A SHIFT MORE TO THE NORTHWEST BY LATE
AFTERNOON.

OUTLOOK…
THU: HIGH OPERATIONAL IMPACT. SHSN LIKELY.
THU NIGHT: MODERATE OPERATIONAL IMPACT. CHANCE OF SHSN IN THE EVNG.
FRI-FRI NIGHT: NO OPERATIONAL IMPACT. NO SIG WX.
SAT-SAT NIGHT: MODERATE OPERATIONAL IMPACT. CHC SHSN.
SUN: LOW OPERATIONAL IMPACT. SLIGHT CHC SHSH.
SUN NIGHT-MON: NO OPERATIONAL IMPACT. NO SIG WX.

&&

.HYDROLOGY…
MUCH BELOW NORMAL TEMPERATURES WILL BE THE GENERAL
RULE WHICH WILL ALLOW ICE TO CONTINUE TO THICKEN ON RIVERS…STREAMS
CREEKS…LAKES AND OTHER BODIES OF WATER.

THERE WILL BE THREAT OF MAINLY LIGHT SNOW LATE TONIGHT INTO THURSDAY
EVENING. SOME NOW MAY ALSO MOVE IN AGAIN SATURDAY NIGHT INTO SUNDAY.

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…WIND CHILL WATCH FROM LATE THURSDAY NIGHT THROUGH FRIDAY
MORNING FOR NYZ032-033-038-042-047-051-058-063-082.
MA…NONE.
VT…NONE.

&&

$$
SYNOPSIS…HWJIV
NEAR TERM…IAA/HWJIV
SHORT TERM…HWJIV
LONG TERM…IAA
AVIATION…IAA/WASULA
HYDROLOGY…HWJIV/KL/WASULA

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