textproduct: Binghamton

WHAT HAS CHANGED

Winds were increased on Friday. PoPs were increased Sunday into Monday as models continue to trend northward with the track of an impactful winter storm.

KEY MESSAGES

1) A clipper system will bring light snow to the region today and tomorrow. Lake effect snow then develops tomorrow night and continues into the start of the weekend.

2) An arctic airmass moves into the region late this week. Dangerous low wind chills likely Friday night into Saturday morning.

3. Confidence continues to increase for an impactful winter storm Sunday morning through Monday morning. While there does remain uncertainty in the forecast, there are increasing chances for widespread accumulating snowfall.

DISCUSSION

KEY MESSAGE 1...

A clipper system will continue to move through the region today with light snow possible, especially across north-central NY. This system will also lift a warm front through with temperatures trending slightly warmer late tonight into Thursday morning. More widespread snow showers are expected overnight with light accumulations possible across central NY and the Northern Tier of PA.

A cold front then moves into the region Thursday morning and will sweep through by the evening. This front will support scattered snow showers as it passes through. While instability is fairly weak and there is not much of a pressure change, there will be gusty winds so squall-like snow showers will be possible Thursday morning with the threat diminishing by the afternoon as drier air moves in. Lake effect snow then develops, but should be north of the region to start. Total snowfall from this clipper system will generally be an inch or less. However, in northern Oneida County, accumulations up to 7 inches will be possible.

The lake effect band may drift south at times into Northern Oneida on Friday. Another cold front will drop in from the north and flow then becomes more northwesterly. This will allow the band to then dip into the Finger Lakes region late Friday and Friday night. High pressure builds into the region Saturday morning and cuts off the lake effect snow. The estimated snowfall totals for the lake effect is sub-advisory with 1 to 4 inches in Onondaga, Madison, and Oneida Counties.

KEY MESSAGE 2...

The aforementioned cold front that drops into the region Friday will bring an Arctic airmass with it. Low temperatures Friday night/early Saturday morning will be below zero across the region. Blustery winds will make it feel even colder as wind chills will be -10 to -30. Little relief is expected Saturday as temperatures only climb into the single digits to low teens but wind chills will struggle to reach the positives despite lighter winds. Saturday night will be warmer but still frigid with lows in the positive and negative single digits and wind chills below zero. No hazards were issued at this time, though an Extreme Cold Watch will likely be needed in N. Oneida if future forecasts remain as cold as this update while the rest of the region would meet advisory criteria.

KEY MESSAGE 3...

Confidence continues to increase that a significant winter storm this weekend will have some impact on the region. This system will move across the south Saturday but then begins to drift northward Saturday night as a strong high retrogrades northward into Canada. Snow will begin to move into the region early Sunday and spread across the region throughout the day as this system tracks up the coast. Snow will continue into Monday but should gradually diminish as the low moves into New England. Then northwest to westerly flow will kick off lake effect snow following this system. While slightly warmer, conditions will stay frigid into early next week.

Confidence has increased with this storm as model and ensemble guidance has trended northward with this system. This is due to them favoring a deeper trough out west and more ridging in the east with the high drifting northward compared to previous runs that had high pressure staying in place and more zonal flow in the east. The system would then ride up the ridge and bring widespread accumulating snowfall to the region. Despite this trend, there is uncertainty with how much the ridge builds and slight differences in timing. Even with this northward trend, the mixed precipitation line should remain well south, though we will have to monitor a dry slot that is now shown in guidance that could result in a brief wintry mix in the far southern portions of the CWA. NBM probabilities for warning level snow (6" in NEPA and 7" in NY) have also increased with at least 50% areawide.

AVIATION /00Z THURSDAY THROUGH MONDAY/

Isolated to scattered snow showers and lower ceilings are expected to linger overnight as the clipper gradually moves east along with its associated cold front. Most of the snow shower activity is likely going to affect only or central NY taf sites, but the highest chance for tempo IFR conditions will be at RME, SYR and ITH...but ELM and BGM could still see some brief IFR or borderline IFR vsbys in snow showers later tonight into THursday morning. The best chance for snow showers will be along the front that pushes through from about 08-12z early Thursday morning. A few scattered snow showers then may linger or redevelop at times into the day on Thursday.

Expect south-southwest winds 7-15 kts, with gusts up around 20 kts gradually decreasing overnight. Winds are west-southwest on Thursday, 10-20 kts.

Occasional southwesterly Low Level Wind Shear (LLWS) is likely at most of our taf sites through daybreak (10-12z Thursday)...before ending. Winds will be around 35-45 kts at 210 degs at 2k ft agl.

Outlook...

Thursday night through Saturday...Mainly VFR, except intermittent lake effect snow showers are possible, generally for SYR-RME-ITH; low confidence on restrictions.

Sunday Into Sunday Night...Potential snow moving in; increasing confidence at this time in timing and track. IFR or lower becoming increasingly likely.

Monday...Lingering snow showers and/or lake effect possible with associated restrictions.

BGM WATCHES/WARNINGS/ADVISORIES

PA...None. NY...Winter Weather Advisory until 1 PM EST Thursday for NYZ009.