FXUS61 KBGM 231139
AFDBGM
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BINGHAMTON NY
639 AM 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/...
300-310 FLOW RESULTING IN LK EFFECT STREAMERS DOWNWIND OF LK ONTARIO
EARLY THIS MRNG. SOME BANDS DROPPING ONE HALF INCH PER HR AMNTS ACRS
UPSTATE NY. THIS PATTERN WILL RMN IN PLACE THROUGHOUT THE DAY WITH
SOME ENHANCEMENT FM UL LOW MVG NOW MVG ACRS NNE. AS UL WV MVS THRU
THIS AFTN EXPECT ENHANCED FORCING AND MORE WIDESPREAD SNOW ACRS THE
REGION...SPECIFICALLY NRN AND ERN PORTION OF THE CWA. EXPECT
LKLY-CAT POPS ACRS MOHAWK VLY/SUSQUEHANNA REGION FOR MOST OF THE DAY
TODAY...WITH SNOW ACCUMS FM 1 TO AS MUCH AS 4 INCHES ACRS THE HIGHER
TERRAIN IN NRN SXNS.
TEMPS NOT CHG MUCH FM PREVIOUS DAYS WITH HIGH IN THE MID 20S
EXPECTED AGAIN THIS AFTN.
&&
.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 TUESDAY/...
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 /12Z WEDNESDAY THROUGH SUNDAY/...
LAKE EFFECT SNOW SHOWERS NOW WILL REMAIN IN ROUGHLY THE SAME PLACE
THROUGH EARLY TONIGHT AS THE MEAN FLOW REMAINS OUT OF THE WEST-
NORTHWEST. DURING THIS TIME MVFR CIGS ARE LIKELY AT ALL OF THE
TERMINALS. MVFR VSBYS WITH PERIODS OF IFR VSBYS ARE POSSIBLE AT
KSYR/KRME AND KBGM THROUGH MID MORNING. A DISTURBANCE ACROSS
NORTHERN NY NOW WILL MOVE SOUTH BY MIDDAY. AS THIS HAPPENS MORE
WIDESPREAD LIGHT SNOW IS EXPECTED BY 15Z AT KSYR/KRME...AND BY 21Z
AT KITH/KBGM. THIS WILL KEEP MVFR CIGS AND VSBYS LIKELY IN AREAS
OF LIGHT SNOW WITH SOME PERIODS OF IFR VSBYS POSSIBLE. THE
EXCEPTION WILL BE AT KAVP WHERE JUST MVFR CIGS ARE EXPECTED WITH
VERY LIGHT SNOW AT MOST. WINDS OUT OF THE WEST- NORTHWEST TODAY
WITH GUSTS TO 20 KTS.
SOME IMPROVEMENT IS POSSIBLE TONIGHT AS THE FLOW VEERS MORE INTO
THE NORTHWEST. THIS SHOULD SHIFT THE BANDS OF SNOW SOUTH OF KSYR
AND KRME...WITH A CONTINUED THREAT AT KITH AND KBGM.
.OUTLOOK...
THU/THU NGT/FRI...VFR.
FRI NGT...MVFR IN MIXED PRECIP.
SATURDAY/SATURDAY NIGHT...MVFR POSSIBLE IN RAIN AND SNOW.
SUN/MON...MVFR WITH AREAS OF LAKE EFFECT SNOW AT NY SITES.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...NONE.
&&
$$
SYNOPSIS...PVN
NEAR TERM...PVN
SHORT TERM...PVN
LONG TERM...HEDEN/MLJ/RRM
AVIATION...HEDEN
