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000
FXUS61 KALY 050508
AFDALY

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ALBANY NY
1159 PM EST WED DEC 4 2013

.SYNOPSIS...
A WEAK HIGH PRESSURE SYSTEM WILL MOVE NORTHEAST...AS WE GO THROUGH
THE FIRST HALF OF THURSDAY INTO SOUTHERN CANADA. CLOUD COVERAGE WILL
INCREASE AS A LOW PRESSURE SYSTEM MOVING NORTH FROM THE GREAT LAKES
WILL HAVE A TRAILING COLD FRONT ASSOCIATED WITH IT THAT WILL MOVE
THROUGH THE REGION THURSDAY NIGHT INTO FRIDAY MORNING. AFTER SOME
POSSIBLE LIGHT SNOW ACCUMULATIONS ON FRIDAY NIGHT...THE REGION WILL
HAVE COLD BUT MAINLY DRY CONDITIONS UNTIL THE NEXT SYSTEM ON MONDAY.

&&

.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
AS OF MIDNIGHT...CLOUDS CONTINUE TO SLOWLY SPREAD
EASTWARD...ASSOCIATED WITH WARM AIR ADVECTION PROCESSES. HIGH
PRESSURE HAS CRESTED OVER THE HUDSON VALLEY ALLOWING TEMPERATURES TO
TUMBLE TO INTO THE 20S...LOWER THAN EARLIER THOUGHT. HOWEVER...WITH
THE INCREASE CLOUDS AND EVENTUALLY A LIGHT SOUTHERLY BREEZE
OVERNIGHT...TEMPERATURES WILL RISE BACK INTO THE 30S.

RADARS INDICTED SOME PRECIPITATION HAS BROKEN OUT WELL TO THE WEST
OF OUR AREA...ACROSS LAKE ONTARIO. THIS AREA WILL LIKELY EXPAND INTO
OUR PORTIONS OF OUR REGION TOWARD DAYBREAK. THE JURY IS STILL OUT
WHETHER OR NOT TEMPERATURES WILL BE ABOVE FREEZING IN OUR NORTHERN
AREAS...QUITE POSSIBLY NOT. CAPITAL REGION SOUTHWARD SHOULD SEE
TEMPERATURES ABOVE FREEZING WHEN AND IF ANY VERY LIGHT RAIN BEGINS TO
FALL BUT WILL CONTINUE TO MONITOR.

&&

.SHORT TERM /6 AM THURSDAY MORNING THROUGH FRIDAY NIGHT/...
AS WE GO INTO THURSDAY MORNING...A WEAK HIGH PRESSURE SYSTEM WILL
MOVE NORTHEAST INTO SOUTHERN CANADA. THIS WILL BE FOLLOWED BY A
COLD FRONT THAT WILL MAKE ITS WAY THROUGH WESTERN NEW YORK AS WE
GO INTO THURSDAY AFTERNOON ASSOCIATED WITH A LOW OVER THE GREAT
LAKES MOVING NORTHEAST INTO EASTERN ONTARIO. HIGH TEMPERATURES ON
THURSDAY OUT AHEAD OF THE COLD FRONT DURING THE DAY WITH A
SOUTHWESTERLY FLOW WILL BE WELL ABOVE AVERAGE RANGING FROM THE LOW
50S TO UPPER 50S ACROSS THE ENTIRE REGION.

THIS COLD FRONTAL SYSTEM WILL BE RELATIVELY SLOW MOVING AS WEAK
UPPER LEVEL WINDS STEER THE FRONT FROM WEST TO EAST. LATEST MODEL
GUIDANCE SUGGEST THAT AS WE GO INTO THURSDAY EVENING...THE COLD
FRONT WILL STILL BE TO THE WEST OF OUR REGION WHICH WILL DELAY ANY
CHANGEOVER FROM RAIN TO WINTRY PRECIPITATION. OVERNIGHT LOW
TEMPERATURES ON THURSDAY NIGHT WILL RANGE FROM THE UPPER 20S TO
NEAR 30 IN THE ADIRONDACKS TO THE UPPER 30S IN LOWER 40S SOUTH AND
EAST OF THE IMMEDIATE CAPITAL REGION.

AS THE COLD FRONT CONTINUES TO MOVE EAST FRIDAY MORNING...THE
TRANSITION FROM RAIN TO A QUICK WINTRY MIX TO SNOW. THE MAIN
FORCING FOR PRECIPITATION AT THIS TIME WILL BE RIGHT ALONG THE
COLD FRONT WHERE HIGHEST ELEVATIONS OF THE ADIRONDACKS WHERE
PRECIPITATION WILL CHANGE TO SNOW FIRST AS T850 WILL RANGE FROM
-1C TO -4C AND T925 WILL RANGE FROM -1C TO -3C EARLY THURSDAY
MORNING. AS THE FRONT PROGRESSES THROUGH THE REGION DURING THE DAY
ON FRIDAY...MAX TEMPERATURES ON FRIDAY WILL OCCUR BEFORE THE COLD
FRONT GOES THROUGH THE REGION WHICH WILL OCCUR EARLY IN THE DAY ON
FRIDAY NORTH AND WEST OF THE IMMEDIATE CAPITAL REGION AND LATER ON
IN THE DAY ON FRIDAY SOUTH AND EAST OF THE IMMEDIATE CAPITAL
REGION. HIGH TEMPERATURES ON FRIDAY WILL RANGE FROM THE MID 30S IN
THE ADIRONDACKS TO MID 40S ACROSS THE MID HUDSON VALLEY.

AS WE GO FROM FRIDAY AFTERNOON INTO FRIDAY EVENING WITH T850 AND
T925 DROPPING BELOW 0C THROUGHOUT THE DAY...LATEST MODEL GUIDANCE
SHOWS A SERIES OF LOW PRESSURE IMPULSES THAT WILL MOVE NORTHEAST
ALONG THE THERMAL GRADIENT. THIS IN CONJUNCTION WITH GOOD 850-700
HPA Q-VECTOR CONVERGENCE AND A GOOD MID LEVEL STRIPE OF
FRONTOGENESIS SETTING UP OFF THE MIDATLANTIC COASTLINE FRIDAY
AFTERNOON...THIS WILL MOVE NORTHEAST UP TO THE SOUTHERN COAST OF
LONG ISLAND AS WE GET INTO FRIDAY NIGHT...WITH ADDITIONAL MOISTURE
FROM THE PACIFIC THAT GENERATED THESE LOW PRESSURE IMPULSES ALONG
WITH AN EASTERLY FLOW OFF THE ATLANTIC...THIS COULD BE A SET UP
FOR LIGHT SNOW ACCUMULATIONS AS WE GO INTO LATE FRIDAY NIGHT. THIS
FORECAST WILL BE UPDATED HOWEVER TO TAKE INTO ACCOUNT THE TIMING OF
THE COLD FRONT AS THE MAIN MESOSCALE FORCING WILL BE ALONG THE
PASSING COLD FRONT. AT THIS TIME...LATEST PROBABILISTIC ENSEMBLE
MEMBERS AND LATEST MODEL GUIDANCE SHOWS THE HIGHEST QPF VALUES
SOUTH AND EAST OF THE IMMEDIATE CAPITAL REGION. THE COLD FRONT
WILL EXIT THE REGION LATER FRIDAY NIGHT. BEHIND THE COLD
FRONT...TEMPERATURES WILL DROP FRIDAY NIGHT WITH LOW TEMPERATURES
RANGING FROM THE UPPER TEENS IN THE ADIRONDACKS TO MID AND UPPER
20S ACROSS THE MID HUDSON VALLEY.

&&

.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
HE PERIOD STARTS OUT ON SATURDAY WITH A NORTHWESTERLY FLOW REGIME
IN PLACE AND COLDER AIR FILTERING INTO THE REGION. THERE COULD BE A
MINOR LAKE RESPONSE WITH SOME LAKE EFFECT SNOW SHOWERS ACROSS THE
WESTERN MOHAWK VALLEY AND SOUTHWESTERN ADIRONDACKS. HOWEVER...HIGH
PRESSURE IS FORECAST TO BUILD IN FAIRLY QUICKLY BY SATURDAY NIGHT
WHICH SHOULD END ANY LAKE EFFECT ACTIVITY. THEN COLDER AND TRANQUIL
WEATHER IS EXPECTED SATURDAY NIGHT THROUGH MOST OF SUNDAY...AS HIGH
PRESSURE DRIFTS ACROSS THE AREA THEN SHIFTS NORTHEASTWARD INTO
SOUTHERN QUEBEC AND NORTHERN NEW ENGLAND LATE SUNDAY.

SUNDAY NIGHT INTO MONDAY...A SYNOPTIC SCALE SYSTEM IS EXPECTED TO
IMPACT THE REGION WITH POTENTIALLY SIGNIFICANT WINTRY PRECIPITATION.
INITIALLY...ENOUGH DEEP LAYER COLD AIR WILL BE IN PLACE SUCH THAT
SNOW WILL DEVELOP FROM SOUTH TO NORTH SUNDAY NIGHT...AS ISENTROPIC
LIFT/WARM ADVECTION INCREASES CONSIDERABLY AHEAD OF A DUAL-CENTER
LOW PRESSURE SYSTEM LIFTING NORTHWARD FROM THE OHIO VALLEY AND
EASTERN SEABOARD RESPECTIVELY. MODELS IN FAIRLY GOOD AGREEMENT WITH
REGARDS TO THE MAIN FEATURES WITH SUBTLE DIFFERENCES...HOWEVER DUE
TO THE PRIMARY LOW LIFTING NORTHWARD THROUGH THE GREAT LAKES AND A
WEAKER SECONDARY LOW EXPECTED ALONG THE NEW ENGLAND COAST...THIS
SYSTEM WILL LIKELY BE DOMINATED BY SOUTHERLY FLOW AND WARMING ALOFT.
WITH A COLD AIR REMAINING TRAPPED IN THE LOW LEVELS DUE TO THE
STRONG DEPARTING HIGH PRESSURE SYSTEM...THE RESULT WILL BE A COMPLEX
VERTICAL THERMAL PROFILE...WITH SNOW TRANSITIONING TO SOME SORT OF A
MESSY WINTRY MIX THEN EVENTUALLY SOME PLAIN RAIN LATER MONDAY.
WINTER WEATHER HEADLINES WILL LIKELY BE NEEDED WITH THIS SYSTEM ONCE
FORECAST CONFIDENCE INCREASES. WILL CONTINUE TO MENTION THREAT IN
THE HWO.

IN WAKE OF THIS SYSTEM THERE COULD BE SOME LEFTOVER LIGHT RAIN
SHOWERS TRANSITIONING TO SNOW SHOWERS MONDAY NIGHT...AS COLDER AIR
WRAPS BACK IN AROUND THE DEPARTING SYSTEM. TUESDAY THROUGH WEDNESDAY
LOOKS TO FEATURE COLDER TEMPERATURES AND A WESTERLY FLOW REGIME WITH
POSSIBLE LAKE EFFECT SNOW NORTH AND WEST OF THE CAPITAL REGION.
BASED ON CURRENT DATA...THE FLOW TRAJECTORY WOULD FAVOR MAINLY THE
WESTERN ADIRONDACKS WITH A POSSIBLE PROLONGED PERIOD OF LAKE SNOWS
THROUGH THE MIDDLE OF NEXT WEEK.

&&

.AVIATION /06Z THURSDAY THROUGH MONDAY/...
VFR CONDITIONS EXPECTED TO PREVAIL THROUGH THE EARLY EVENING
HOURS ACROSS THE TERMINALS...WITH JUST SOME PASSING SCT-BKN MID
LEVEL CLOUDS...ESPECIALLY FROM KALB NORTHWARD.

LOWER LEVEL STRATUS CLOUDS ARE EXPECTED TO INCREASE LATER THIS
EVENING...AS THE FLOW TURNS MORE SOUTHERLY. WITH LINGERING LOW LEVEL
MOISTURE SOME LIGHT FOG MAY ALSO ACCOMPANY THE STRATUS. CONDITIONS
ARE EXPECTED TO DETERIORATE TO MVFR THEN IFR LATE TONIGHT AS CIGS
LOWER AND VSBY BECOMES MARGINAL AS WELL. WARMER AIR WILL BE MOVING
IN ALOFT WHICH WILL TRAP THE LOW LEVEL STRATUS AND FOG...SO
EXPECTING IFR CONDITIONS TO CONTINUE THROUGH 15Z-18Z THURSDAY.
WINDS WILL BE LIGHT AND VARIABLE...BECOMING SOUTHEAST AROUND 3 TO
7 KT THURSDAY MORNING.

OUTLOOK...
THURSDAY: MODERATE OPERATIONAL IMPACT. LIKELY SHRA
THURSDAY NIGHT TO FRIDAY: HIGH OPERATIONAL IMPACT. LIKELY RA
FRIDAY NIGHT: MODERATE OPERATIONAL IMPACT. CHANCE OF RA...SN...SLEET.
SATURDAY TO SUNDAY: NO OPERATIONAL IMPACT. NO SIG WX.
SUNDAY NIGHT: HIGH OPERATIONAL IMPACT. LIKELY SN.
MONDAY: HIGH OPERATIONAL IMPACT. LIKELY RA...FZRA...SLEET.

&&

.HYDROLOGY...
NO HYDRO RELATED CONCERNS ARE EXPECTED OVER THE NEXT 5 DAYS.

THURSDAY NIGHT INTO FRIDAY...AS A STRONG COLD FRONT GRADUALLY
PUSHES THROUGH OUR REGION...A WAVE OF LOW PRESSURE WILL LIKELY
PRODUCE A BIT MORE SIGNIFICANT RAINFALL ACROSS MAINLY OUR CENTRAL
AND SOUTHERN AREAS WHERE ONE QUARTER TO ONE INCH OF RAIN COULD
FALL. THESE RAINFALL AMOUNTS WOULD BE ENOUGH TO PRODUCE SOME
WITHIN BANK RISES ON MAIN STEM RIVERS...HOWEVER NO FLOODING IS
EXPECTED.

IT WILL THEN TURN COLDER AFTER THIS SYSTEM FINALLY PUSHES THROUGH
FRIDAY NIGHT WITH ANY ADDITIONAL PRECIPITATION FALLING AS LIGHT SNOW.
IT LOOKS MAINLY DRY SATURDAY INTO SUNDAY BEFORE THE NEXT STRONG
STORM SYSTEM APPROACHES SUNDAY NIGHT INTO MONDAY. IT LOOKS COLD
ENOUGH FOR MAINLY SNOW AND/OR MIXED PRECIPITATION TO FALL WITH THIS
SYSTEM AT THIS TIME...POSSIBLY ENDING AS SOME RAIN.

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/LFM/NAS
NEAR TERM...HWJIV/LFM/NAS
SHORT TERM...LFM
LONG TERM...JPV
AVIATION...NAS
HYDROLOGY...HWJIV/LFM/JPV