textproduct: Binghamton

SYNOPSIS

A series of clipper systems will brings periods of snow to late tonight and on Wednesday. Lake effect snow and much colder temperatures are expected behind this system heading into Thursday and Friday. Periods of snow showers and well below average temperatures continue for the upcoming weekend across the region.

NEAR TERM /THROUGH TODAY/

Main concern in the near term period will be the stronger low pressure/clipper system impacting the area Wednesday into Wednesday night. Winter storm warnings, watches and advisories have been issued for portion of the CWA, for this and the lake effect that follows.

A weak warm front will push through the area late this afternoon and evening bring some light snow or flurries to north-central NY. This will be a very minor event, as the snow struggles to reach the ground under the high dew point depression air mass which is in place. Dustings to perhaps 1 inch of snow expected, mainly across northern Oneida county. After this light snow or flurries moves out, there will be a break, with dry and mostly cloudy conditions overnight. It will be cold with lows in the mid-10s to mid-20s. South winds continue overnight between 10-20 mph in most areas.

The next, much stronger low pressure system begins to approach late tonight and move just north of the area on Wednesday. Warm air advection snow looks to quickly develop and overspread the area between about 4-8 AM Wednesday morning. Steady snow then impacts much of the area Wednesday morning, there could however be a few holes in the snow, where the strong south-southwest winds in the 1000-850mb layer downslope across the central southern tier or NY and the western Finger Lakes regions. The biggest uncertainty will be for areas surrounding this snowfall minimum, such as S. Cayuga, Tompkins, Tioga and Broome counties...how sharp will that gradient be from little snow west (< 1") to steadier, advisory level snow amounts (2-5") east. Right now, model guidance puts that large gradient across these 4 counties noted above. Broome county is particularly tough, with amounts likely ranging from 2 inches or less in the Susquehanna Valley region (Tri-Cities), with up to 4-5 inches over the higher elevations of the far east-northeastern portion of the county. Higher elevations will see more snow than the valley.

Further east and north confidence is high in advisory level amounts, of 2 to 5 inches, with localized amounts up to 7 inches in the higher elevations of the Catskills and northern Susquehanna regions. Confidence is also high for Northern Oneida County reaching Winter Storm Warning criteria of 6-12 inches Wednesday into Thursday morning here. The other question will be low level temperatures, and if any rain or freezing rain mixes in. The highest probability to see a little freezing rain and light glazes of ice will be across NE PA and perhaps into southern Sullivan county in NY, where temperatures aloft get close to, or just above 0C Wednesday morning...can't rule it out further north even into the portions of CNY, very briefly. Our latest forecast trended surface temperatures lower Wednesday afternoon, based on the latest guidance and considering how cold ground temperatures are now.

The snow (and valley rain) gradually tapers off late Wednesday afternoon as the main low moves over eastern Lake Ontario. A sharp cold front will pass through the area from west to east Wednesday evening, bringing temperatures back down below freezing just above everywhere by midnight. Wrap around snow showers and lake effect/enhanced snow then develops and impact CNY heading into Wednesday night with light additional accumulations possible. A lake effect snow band then likely sets up late Wednesday night up across the Onondaga--Madison--S. Oneida county with the snow rates potentially ramping up again here. Otherwise, it will be turning much colder overnight with lows in the mid-10s to lower 20s. West- northwest winds also start to increase between 10-20 mph with slightly higher gusts. This could cause areas of blowing snow. A Winter Storm Watch has been issued for Onondaga--Madison and S. Oneida counties starting at 1 AM Thursday morning, all the way through 7 AM Friday. More details below on this.

SHORT TERM /TONIGHT THROUGH FRIDAY NIGHT/

Main concern in this period will be the potential for ongoing significant lake effect snow; mainly across Onondaga, Madison and southern Oneida counties. As the previously mentioned low slowly pulls east-northeast of the area a lingering 500mb and 700mb low will setup and almost stall over the Adirondacks and northern New England through the day on Thursday. By Thursday night and Friday morning it finally shifts east into the Canadian Maritimes. With this mid and upper level low nearby on Thursday, our forecast area will be under a very cold and moist NW flow pattern. Expect 850mb temperatures around -16C Thursday afternoon, with forecast soundings showing moisture saturation depths up to to nearly 15-20K feet, or 550mb. GFS profiles show a strong bullseye of omega centered right in the snow growth layer Thursday morning at Syracuse. If this does in fact occur, this would be very favorable for highly efficient snow accumulation and high snowfall rates. As mentioned above, a winter storm watch for lake effect has been issued to cover this potential. Right now the overall flow pattern looks to vary between about 280- 300 degrees, which would again target the I-90 corridor and perhaps just south for the highest lake effect snow totals. The moisture depth gradually lowers below 800mb Thursday night, but the moisture remains centered within the snow growth zone in the soundings. This will allow light to moderate lake effect snow to continue.

Outside of the main lake effect zones, there will be scattered snow showers and even a few snow squalls around on Thursday. The other main story for Thursday will be the increasingly gusty winds, with soundings showing the potential for gusts of 30-40 mph through the day. This can cause areas of blowing and drifting snow in the open and exposed areas that receive fresh, new snow. It will be cold with highs only in the 20s (except low 30s Wyoming Valley). Thursday night will feature more scattered snow showers and flurries outside of the main lake effect counties noted above, with overnight lows in the 10s once again.

On Friday, there will be some lingering lake effect snow showers up across the Syracuse metro area, otherwise a weak wave approaches from the Ohio Valley in the afternoon with more clouds and slight chance of light snow reentering the forecast. Temperatures below freezing and below normal.

LONG TERM /SATURDAY THROUGH TUESDAY/

This period features well below average temperatures, with a strong arctic front pushing through the area Sunday morning. A low pressure system also slides by to our south bringing another round of snow or snow showers Saturday night into Sunday morning. By Sunday afternoon, through Monday a cold 500mb low is progged to be sitting over the area. This will bring sub 504dm thicknesses, with 850mb temperatures down to almost -20C. With the upper level low overhead, snow showers and bitter cold conditions look to continue Sunday and Monday, with wind chills likely below zero Sunday night and Monday morning. The bitter cold begins to slowly ease and moderate some as a weak clipper moves through Monday night into next Tuesday.

AVIATION /06Z WEDNESDAY THROUGH SUNDAY/

Ceilings are slowly lowering close to MVFR ahead of the incoming low pressure system. Snow is expected to move in from west to east starting around 10z. IFR restrictions are expected to quickly follow at all CNY terminals, lasting through the day as snow changes to a mix of rain and snow at lower elevations. AVP should see IFR restrictions during the afternoon hours. Broad snow exits in the evening with lingering showers remaining. A mix of IFR and MVFR Ceilings will remain. SYR and RME should see snow showers a through the end of the TAF period, keeping conditions IFR.

LLWS of 35-40kts up to FL020 will be present across the area for a few hours tonight, picking up again around sunrise and through the morning hours.

Outlook...

Wednesday night through Thursday night...Restrictions likely in lake effect snow showers and squalls, especially at SYR and RME.

Friday through Sunday...Occasional restrictions possible in scattered snow showers. Period of steadier accumulating snow possible Saturday night for KAVP, perhaps into KELM and KBGM as well.

BGM WATCHES/WARNINGS/ADVISORIES

PA...Winter Weather Advisory until 7 PM EST this evening for PAZ038>040-043-044-047-048-072. NY...Winter Storm Warning until 1 PM EST Thursday for NYZ009. Winter Weather Advisory until 1 AM EST Thursday for NYZ017-018- 036-037-044>046-057-062. Winter Storm Watch from late tonight through Friday morning for NYZ018-036-037. Winter Weather Advisory until 7 PM EST this evening for NYZ056.