FXUS61 KBGM 231724
AFDBGM
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BINGHAMTON NY
1224 PM EST WED DEC 23 2009
.SYNOPSIS...
AN UPPER LEVEL DISTURBANCE COMBINED WITH LAKE MOISTURE WILL BRING
SNOW SHOWERS ACROSS UPSTATE NEW YORK TODAY...GRADUALLY WINDING DOWN
LATE TONIGHT. NEAR NORMAL TEMPERATURES AND DRY WEATHER CAN BE
EXPECTED ON THURSDAY AS HIGH PRESSURE MOVES INTO THE AREA. THE NEXT
STORM SYSTEM WILL SPREAD A MIX OF PRECIPITATION INTO THE AREA ON
CHRISTMAS DAY. THIS WINTRY MIX WILL CONTINUE THROUGH FRIDAY
NIGHT...TRANSITIONING TO RAIN DURING THE DAY SATURDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
HAVE GOTTEN A FEW REPORTS OF 4 TO 5 INCHES OF SNOW SINCE LAST NIGHT
IN MULTI-BAND SNOW SHOWERS SOUTHEAST OF LAKE ONTARIO. A SHORT WAVE
TROUGH IS FORECAST TO ROTATE SOUTH AROUND THE CLOSED LOW OVER NORTHERN
NEW ENGLAND THIS AFTERNOON. THIS IS FORECAST TO DEEPEN THE MOISTURE
AND WILL RESULT IN SEVERAL HOURS OF DEEP MOISTURE IN THE DENDRITIC
SNOW GROWTH LAYER OVER CENTRAL NY THIS AFTERNOON. THE FLOW IS FORECAST
TO REMAIN BETWEEN 300 AND 315 DEGREES WHICH WILL CONTINUE TO FAVOR THE
ZONE FROM CAYUGA TO SOUTHERN ONONDAGA...CORTLAND AND NORTHERN CHENANGO
COUNTIES. BASED ON THIS HAVE ISSUED AN ADVISORY FOR UP TO 5 INCHES OF
ADDITIONAL SNOWFALL IN THAT AREA THROUGH THIS EVENING.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH FRIDAY NIGHT/...
PCPN WL SLOWLY WIND DOWN LATE TONIGHT AS INVERSION CRASHES AND FLOW
GOES MORE NRLY. SCTD SNOW SHOWERS STILL JUSTIFIED THRU 09Z TONIGHT
BFR DROPPING TO SLGT CHC AFT THIS TIME.
H5 LOW OVR DESERT SW WILL MV E-NE THRU MID-WEEK. UL RIDGE WILL
AMPLIFY AHD OF THIS FEATURE...ALLOWING FOR A BRIEF BREAK IN THE PCPN
DRG THE DAY THURSDAY AND INTO THUR NGT. SFC LOPRES WILL DEEPEN ACRS THE
SRN PLAINS BY THUR AFTN. WITH TROF EXPECTED TO GO NEGATIVE AND SFC
LOW DEEPENING...SYSTEM CONTS TO SLOW DOWN AS PROGGED BY MODEL
GUIDANCE.
BY CHRISTMAS DAY CLOSED LOW WILL DRIFT OFF TO THE NORTH WITH SFC
BNDRY SLOWLY MEANDERING INTO MIDWEST AND EVENTUALLY INTO NE U.S. DRY
AIR ASSOC WITH UL RIDGE WILL KEEP MEASURABLE PCPN AT BAY THRU
CHRISTMAS MRNG.
MOIST SE FLOW KICKS IN FM THE MID-ATLANTIC FRI MRNG...LKLY SPREADING
A LOW STRATUS LAYER INTO SRN AND WRN SXNS OF THE CWA BY 12Z. WITH
TEMPS BLO FRZG AND SIGNIFICANT MOISTURE WORKING IN HV ADDED IN THE
POSSIBILITY FOR LGT FREEZING DRIZZLE BTWN 12Z-18Z. PCPN WILL BE
COUNTERACTED FURTHER NORTH AND WEST BY STRONG HIGH OVR ERN CANADA
SHUNTING MOISTURE AWAY FM AREA.
FCST WILL BE TRICKY FOR CHRISTMAS DAY AS WEDGING WILL KEEP SHALLOW
COLD AIRMASS IN ACRS THE CWA FOR A GOOD PART OF THE DAY. MODELS
NOTORIOUSLY HV A HARD TIME DEALING WITH SHALLOW COLD AIR AND AM
CONCERNED THAT GUIDANCE MAY BE WARMING TEMPS UP TOO MUCH ON
FRIDAY...ESPECIALLY OVR ERN AREAS.
STILL SOME DISCREPANCIES ON HOW QUICKLY PCPN MVS INTO FA FRI AFTN.
00Z NAM IS THE FASTEST WITH GFS/EURO LAGGING SLIGHTLY BHND. THINK
SLOWER IS BETTER IN THIS CASE GIVEN EXTENT OF COLD HIPRES
INFLUENCING AIRMASS ACRS THE EAST. WILL BACK OFF SOME ON POPS ACRS
THE EAST BUT BOOST POPS A TAD OVR WRN SXNS FOR FRI AFTN.
BUFKIT PROFILES PER NAM/GFS BOTH LOOK TO BE FAIRLY ISOTHERMAL AT
ONSET OF PCPN WITH SFC TEMPS SLIGHTLY COLDER FM NAM. EXPECT A
HODGE-PODGE OF PCPN TYPE ON FRIDAY WITH RAIN/SLEET ACRS THE WEST AND
RAIN/SNOW/SLEET FURTHER TO THE EAST. COLD AIR WILL LKLY HOLD IN
LONGER ACRS THE EAST SO PD OF FREEZING RAIN WILL BE LKLY A GOOD PART
OF THE DAY EAST OF I-81 AND IN ISOLD POCKETS ACRS THE EAST.
CAT POPS DEFINITELY WARRANTED FOR FRI NIGHT AND WILL RETAIN P-TYPE
GRIDS ISSUED BY PVS SHIFT. SEE NO REASON TO CHG AT THIS POINT AS MIN
TEMPS WILL LKLY MV VRY LITTLE OVRNGT. THUS THERE WILL LKLY BE A
CONGLOMERATION OF RA/FZRA/IP FOR MOST OF THE NIGHT. AS OF
NOW...POTENTIAL EXISTS FOR 0.10-0.25 INCHES OF ICE ACCUMULATION FM
FRI MRNG THRU SAT AFTN.
WILL CONTINUE TO HIGHLIGHT THREAT IN HWO AND CONTINUE TO MONITOR FOR
POSSIBLE HEADLINES WITH LATER FORECASTS. AS OF NOW...APPEARS AS
THOUGH ADVISORY CRITERIA WILL BE MET FM LIGHT ICING BUT ANYTHING CAN
HAPPEN OVR THE COURSE OF THE NEXT 2 DAYS.
&&
.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
UPDATED AS OF 255 AM...TRANSITION FROM FREEZING RAIN TO RAIN WILL
CONTINUE EARLY SATURDAY FROM WEST TO EAST. BY 12Z MOST AREAS FROM 81
WEST SHOULD BE ABOVE FREEZING...EVEN IF ITS JUST BY A DEGREE OR SO.
IN OUR NORMALLY COLDER AREAS EAST OF I-81...TEMPS WILL START OUT
BELOW FREEZING...WITH SOME LOCATIONS HOLDING IN THE UPPER 20S.
TOWARD 18Z THESE AREAS WILL SEE A SLOW CLIMB ABOVE FREEZING WITH THE
TRANSITION TO RAIN. TOTAL ICE AMOUNTS ARE STILL UNCERTAIN THIS FAR
OUT. BEST GUESS AT THIS POINT WOULD BE AROUND A TENTH OF AN INCH FOR
MOST OF THE AREA...WITH UP TO A QUARTER OF AN INCH IN THE COLDER
VALLEYS EAST OF I-81. ASIDE FROM THE ICE POTENTIAL EARLY
SATURDAY...IT WILL BE BREEZY THANKS TO THE PRESSURE GRADIENT BETWEEN
HIGH PRESSURE OVER THE CANADIAN MARITIMES AND A SECONDARY LOW OVER
THE MID-ATLANTIC.
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. BY TUESDAY HIGH TEMPS ARE
EXPECTED TO BE BELOW NORMAL AS A CORE OF COLD AIR SLIDES TO OUR
NORTH. THE 0Z EURO IS NOT QUITE AS COLD AS THE PREVIOUS RUN BUT
BOTH THE 0Z GFS AND EURO SHOW 925 TEMPS DROPPING TO -14C...WHICH
WOULD MEAN HIGHS IN THE LOWER TO MIDDLE 20S FOR MOST OF THE CWA.
&&
.AVIATION /18Z WEDNESDAY THROUGH SUNDAY/...
AN BAND OF SNOW IS ROTATING S ACROSS NY STATE IS ASSOCIATED WITH A
LARGE UPPER LEVEL LOW OVER NEW ENGLAND. NW WINDS OFF LAKE ONTARIO IS
ENHANCING THE LOW CLOUDS AND SNOW. WIDESPREAD MVFR CIGS AND VSBY IS
THE RESULT WITH ISOLD IFR CONDITIONS IN HEAVIER SNOW. NW WINDS ARE
10-15 KT AT SFC WITH GUSTS TO 20KT AND INCREASE TO 30KT BY 5K FEET.
SNOW WILL BEGIN TO DIMINISH FROM N TO S AROUND 00Z. SOME BREAKS IN
THE CLOUDS WITH BRIEF VFR CONDITIONS IS POSSIBLE BETWEEN 00Z AND
06Z. THE EXCEPTION TO THIS IS IN THE KITH AND KELM AREAS WHERE
SOME FINGER LAKE BANDS MAY DEVELOP. CLOUDS ARE EXPECTED TO FILL
ALL AREAS TOWARD MORNING WITH MVFR CIGS. WINDS WILL DIMINISH
OVERNIGHT AND SHIFT TO NE 5-10 KT THUR MORNING.
A RIDGE OF HIGH PRESSURE WILL BUILD IN FOR THURSDAY WITH
GENERALLY VFR CONDITIONS BY 18Z AND CONTINUING OVERNIGHT. WINDS
WILL BE LIGHT.
.OUTLOOK...
FRI...VFR.
FRI NGT...MVFR IN MIXED PRECIP.
SATURDAY/SATURDAY NIGHT...IFR POSSIBLE IN RAIN AND SNOW.
SUN/MON...MVFR WITH AREAS OF LAKE EFFECT SNOW AT NY SITES.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...LAKE EFFECT SNOW ADVISORY UNTIL 1 AM EST THURSDAY FOR NYZ017-
018-036-044-045.
&&
$$
SYNOPSIS...PVN
NEAR TERM...MSE
SHORT TERM...PVN
LONG TERM...HEDEN/MLJ/RRM
AVIATION...BMW
