FXUS61 KBGM 230551
AFDBGM
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BINGHAMTON NY
1251 AM EST WED DEC 23 2009
.SYNOPSIS...
A TROUGH OF LOW PRESSURE WILL DROP SOUTHWARD LATE TONIGHT AND
WEDNESDAY...ACROSS CENTRAL NEW YORK. THIS DISTURBANCE WILL COMBINE
WITH LAKE MOISTURE...TO BRING A NEW ROUND OF SNOW SHOWERS. SNOW
SHOWERS WILL GRADUALLY DIMINISH WEDNESDAY NIGHT...BEFORE HIGH
PRESSURE BUILDS IN FROM THURSDAY INTO CHRISTMAS DAY...WITH DRY
CONDITIONS. FROM FRIDAY AFTERNOON INTO THE WEEKEND...A COMPLEX
STORM WILL APPROACH...AND THREATEN THE AREA WITH A WINTRY MIX OF
PRECIPITATION.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
UPDATED 6PM...WITH ONLY A SMALL AREA OF LIGHT SNOW IN THE SYRACUSE
AREA...AND CLEAR SKIES OVER MUCH OF THE CWA...HAVE REDUCED POPS
THROUGH 6Z TONIGHT. ALSO...WITH THE CLEAR SKIES...HAVE DROPPED
EXPECTED LOWS BY SEVERAL DEGREES.
PREVIOUS DISCUSSION...FROM LATE THIS AFTERNOON INTO THE EARLY EVENING...A
SMALL PLUME OF MOISTURE OFF LAKE ONTARIO...WILL CONTINUE TO BRING
FLURRIES ACROSS OUR NORTHERN ZONES
(ONONDAGA/MADISON/ONEIDA/CORTLAND/CHENANGO PRIMARILY).
ELSEWHERE...IT WILL REMAIN GENERALLY DRY AND CHILLY.
FROM LATER THIS EVENING THROUGH THE OVERNIGHT HOURS...MODEL
AGREEMENT IS FAIRLY GOOD...THAT SYNOPTIC-SCALE MOISTURE WILL
INCREASE FROM NORTH TO SOUTH...AS AN UPPER-LEVEL WAVE ROTATES
AROUND THE CLOSED CIRCULATION MOVING INTO NORTHERN NEW ENGLAND.
AT THE SAME TIME...MOISTURE WILL REMAIN BELOW THE INVERSION BASE
(SURFACE TO ABOUT 850 MB)...WITH A PERSISTENT 310 FLOW. THIS
COMBINATION OF LES MECHANICS AND SYNOPTIC ENHANCEMENT SHOULD
INCREASE BOTH THE INTENSITY AND COVERAGE OF SNOW SHOWERS OVER
CENTRAL NY. OUR BEST IN-HOUSE LES ANALOGS (WHICH SEEM TO MATCH THE
DEEP MOISTURE/DENDRITE PROFILE WELL) SHOW THE POTENTIAL FOR 2-3"
OF ACCUMULATION BY DAYBREAK...IN THE MOST PERSISTENT BANDS. THE
BEST CHANCE FOR THIS APPEARS TO BE ACROSS ONONDAGA/MADISON/FAR
SOUTHERN ONEIDA/CORTLAND/CHENANGO/OTSEGO COUNTIES...PERHAPS EDGING INTO
THE FINGER LAKES REGION...AS WELL AS NORTHERN BROOME/DELAWARE.
FARTHER SOUTH ACROSS NORTHEAST PA...ONLY FLURRIES ARE EXPECTED
TOWARDS DAYBREAK...AND EVEN THEN MAINLY NORTH OF SCRANTON.
WITH CLEAR SKIES PROBABLY HANGING ON LONGER IN OUR SOUTHERN
ZONES...WE WENT WITH COLDER LOW TEMPERATURES IN THESE AREAS.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH FRIDAY/...
SNOW SHOWERS WILL BE ONGOING WEDNESDAY MORNING. THIS ACTIVITY
SHOULD START TO DIMINISH IN THE AFTERNOON...AS WE LOSE THE DEEPER
MOISTURE...AND THE COLDEST AIR GETS SHUNTED TO OUR EAST. BY THIS
TIME...SNOW TOTALS OF 1-3" SHOULD BE COMMON IN MANY PARTS OF
CENTRAL NY...EITHER SIDE OF THE I-81 CORRIDOR...WITH LOCALIZED
AREAS PERHAPS SEEING 4-5".
BREAKS OF SUNSHINE SHOULD BE ON THE INCREASE DURING THE AFTERNOON
ACROSS MUCH OF NORTHEAST PA.
WEDNESDAY NIGHT...THE LOW-LEVEL FLOW VEERS INTO THE NORTH...AND
EVENTUALLY NORTHEAST...WITH CONTINUED DRYING. ANY LINGERING LIGHT
SNOW SHOWERS/FLURRIES IN THE EVENING DOWNWIND OF LAKE ONTARIO AND
THE FINGER LAKES...SHOULD DISSIPATE LATE AT NIGHT.
THURSDAY...CHRISTMAS EVE...AND CHRISTMAS MORNING...DRY WEATHER IS
FORESEEN...AS HIGH PRESSURE SLIDES ACROSS THE REGION. ON
THURSDAY...HIGH TEMPERATURES WILL BE SOMEWHAT MILDER THAN RECENT
DAYS (GETTING INTO THE 30S MANY PLACES)...AS THE AIR MASS
CONTINUES TO MODIFY...AND OUR PREVAILING FLOW TAKES ON A SOUTHERLY
COMPONENT.
FRIDAY AFTERNOON...MODEL CONSENSUS REMAINS GOOD...THAT A DEEP STORM
WILL TRACK SLOWLY NORTHWARD THROUGH THE MIDWEST...WHILE SURFACE
HIGH PRESSURE HANGS TOUGH...EXTENDING FROM QUEBEC DOWN THE EASTERN
SEABOARD. MOISTURE ADVECTING IN FROM THE SOUTH AND
SOUTHWEST...WITH GRADUALLY IMPROVED FORCING...WILL BRING THE
LEADING EDGE OF LIGHT PRECIPITATION CLOSER TO OUR AREA. IF
ANYTHING...THE MODELS ARE TRENDING SLOWER WITH THE ONSET OF THIS
PRECIPITATION. THIS COULD BE A REASONABLE SCENARIO...WITH VERY DRY AIR
IN PLACE INITIALLY. FOR NOW...WE'LL CONTINUE TO BRING IN CHANCE
PROBABILITIES...MAINLY AFTER 18Z.
PRECIPITATION TYPE IS ANOTHER ISSUE. CURRENT MODEL SOUNDING
PROFILES...ALONG WITH A SEEMINGLY FAVORABLE POSITION OF THE
SURFACE RIDGE FOR COLD AIR SUPPLY...WOULD SUGGEST EITHER FROZEN OR
FREEZING PRECIPITATION AT THE START...AND WE'VE BASICALLY GONE
WITH A CHANCE OF EITHER SNOW...SLEET...OR FREEZING RAIN INITIALLY.
THE AREAS THAT HAVE THE BEST CHANCE TO SEE READINGS CLIMB ABOVE
FREEZING BY LATE AFTERNOON...AND EXPERIENCE JUST RAIN...WOULD BE
OUR LAKE-PLAIN/FINGER LAKES COUNTIES. WE'LL CONTINUE TO MENTION
THE POTENTIAL FOR A WINTRY MIX IN THE HWO...WITH MORE ON THIS
EVENT IN THE LONG-TERM SECTION BELOW.
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
FRIDAY NIGHT/SATURDAY...
MIXED PRECIPITATION EVENT WILL LIKELY TAKE PLACE THIS PERIOD...AS
RELATIVELY WARM MOIST AIR FROM THE SOUTH...OVERRUNS THE COLD DOME OF
AIR IN PLACE AT LOWER LEVELS.
THE BEST CHANCE FOR ANY PROLONGED ICING LOOKS TO BE ACROSS OUR
EASTERN ZONES (SOUTHERN TUG HILL/MOHAWK VALLEY/CATSKILLS)...WHERE
THE BEST SUPPLY OF COLD AIR WILL BE AVAILABLE...VIA COLD EASTERN
CANADIAN HIGH PRESSURE. ELSEWHERE...A WINTRY MIX FRIDAY NIGHT...AND
POSSIBLY EARLY SATURDAY...SHOULD ULTIMATELY TURN TO RAIN/DRIZZLE.
SATURDAY NIGHT COLD AIR ADVECTION BEGINS AS SECONDARY LOW MOVES
INTO NEW ENGLAND WITH PRIMARY LOW BACK ACROSS UPPER GREAT LAKES.
WILL START SATURDAY EVENING WITH CHC POPS FOR MIXED RAIN/SNOW
SHOWERS THEN AS COLUMN COOLS TOWARD MIDNIGHT JUST SNOW SHOWERS.
SUNDAY THROUGH TUESDAY, UPPER LEVEL TROF REMAINS OVER THE REGION
WITH WEST/NORTHWEST FLOW OF SEASONAL AIR. MINS WILL GENERALLY
RANGE IN THE UPPER TEENS WITH HIGHS AROUND 30. WILL ADVERTISE CHC
POPS THROUGH PERIOD PRIMARILY DOWNWIND OF LAKE ONTARIO WHERE LAKE
EFFECT SNOW SHOWERS ARE MOST PROBABLE.
&&
.AVIATION /06Z WEDNESDAY THROUGH SUNDAY/...
INCREASING MOISTURE COMBINED WITH NORTHWEST WINDS WILL RESULT IN
WIDESPREAD FLIGHT RESTRICTIONS THROUGH THIS AFTERNOON. THE MOST
PERSISTENT LAKE EFFECT SNOW SHOWERS WILL BE AT KITH/KBGM WHERE
A HIGH CONFIDENCE EXISTS FOR MVFR CIGS/VSBYS THROUGH AT LEAST
MORNING...AND POSSIBLY INTO THE AFTERNOON. KBGM STANDS THE HIGHEST
THREAT FOR IFR VSBYS DUE TO THE SLIGHTLY HEAVIER NATURE OF THE
SNOW SHOWERS AT THE TERMINAL. CONFIDENCE IN THE EXACT INTENSITY OF
THE BAND DIMINISHES AFTER 08Z SO I INCLUDED A TEMPO GROUP OF IFR
VSBYS FOR NOW. KELM SHOULD BE OUT OF THE LAKE EFFECT SNOW SHOWERS
BUT WILL BE IMPACTED BY MVFR CIGS IN LAKE CLOUDS DURING THIS SAME
STRETCH.
FARTHER NORTH...KSYR AND KRME WILL LIKELY BE NORTH AND EAST OF MOST
OF THE LAKE EFFECT ACTIVITY THROUGH 10Z. AFTER THAT TIME SYNOPTIC
MOISTURE FROM THE NORTH WILL INCREASE THE LIKELIHOOD OF MVFR CIGS
IN SNOW SHOWERS.
.OUTLOOK...
WED NGT/THU/THU NGT/FRI...VFR.
FRI NGT...MVFR IN MIXED PRECIP.
SATURDAY/SATURDAY NIGHT...MVFR POSSIBLE IN RAIN AND SNOW.
SUN...MVFR.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...NONE.
&&
$$
SYNOPSIS...MLJ
NEAR TERM...MLJ/10
SHORT TERM...MLJ
LONG TERM...MLJ/RRM
AVIATION...HEDEN
