textproduct: Binghamton

WHAT HAS CHANGED

Extreme Cold Watch issued for Northern Oneida County for Friday night through early Saturday afternoon.

Winter Storm Watch issued for the entire forecast area early Sunday morning through Monday due to the potential for widespread heavy snow.

KEY MESSAGES

1) A clipper system continues to bring snow across Central NY with a winter weather advisory out for northern Oneida County until this afternoon. Lake effect snow then develops tonight and continues into the start of the weekend, but it will mostly miss our region.

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

3. Significant winter storm possible Sunday morning through Monday.

DISCUSSION

KEY MESSAGE 1...

A cold front is pushing through the region early this morning and is producing heavy snow showers and squalls across the western forecast area. The snow has been quite intense with this squall and it has even produced a few lightning strikes, but with it being 230 am, an SPS has been issued instead of a snow squall warning. If this squall can hold together as it crosses central NY, then squall warnings may be needed as we near the morning commute in a few hours.

Behind this front, lake effect snow develops, but the heavy snow bands should remain mostly north of the region through tonight, but as flow turns more westerly to northwesterly on Friday, the band should drift southward into northern Oneida County at times. By this Friday evening, the band is forecast to dip into the Finger Lakes region and persist with snow showers into Saturday morning. 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 generally 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. A extreme cold watch has been issued for northern Oneida County with this update as wind chill values there could dip to or below minus 30F. Saturday night will be warmer ahead of our incoming winter storm, but still frigid with lows in the positive and negative single digits and wind chills below zero. Cold weather Advisories will likely be need for rest of the forecast area for Friday night through Saturday, but one shouldn't be needed Saturday night into Sunday.

KEY MESSAGE 3...

A significant winter storm is forecast to impact the region Sunday morning through Monday. Models are now in much better agreement, however, some swings in the projected storm track and the swath of heavy snow is still likely to change some...as we are still over 72 hours out before the first flakes start to fly in our region. However, forecast confidence is high enough that we will at least see widespread warning level snowfall (6 in NEPA and 7 in NY), so a Winter Storm Watch has been issued for the entire CWA.

Snow will begin to move into the region early Sunday morning and spread across the region from southwest to northeast throughout the day. Snow will continue into Monday, but should gradually diminish as the low moves into New England. A swath of very heavy snow will be possible with this system as mesoscale banding is looking likely. It is still too early to forecast where this heavy band of snow will set up, but early forecast soundings for AVP and BGM are quite impressive. Both soundings show a very deep and saturated dendritic growth zone from the surface to over 15K feet with strong OMEGA through the layer. Snow ratios will be interesting with this system and would not be surprised if some locations exceed a 20:1 ratio with what the soundings are indicating. So, even if a forecast QPF is 0.60, this could possibly yield snowfall totals of a foot or more. Also, would not be surprised to see snowfall rates under this mesoscale band exceed 1 - 2" per hour at times. Finally, at this time, it is looking unlikely that we will see any mixing in our forecast area, but if there is more shifting to the north in the coming days, then it is possible for some wintry mix to sneak into our far southern forecast area in NEPA.

This system will exit Monday afternoon, however, in its wake, wraparound moisture and northwest to westerly flow off the lakes will likely kick off lake effect snow. While the start of next week will be slightly warmer, conditions will still be frigid and remain below normal through the week. Also, with troughing likely remaining over the NE US through at least the end of the month, the pattern will remain favorable for more winter storms.

AVIATION /18Z THURSDAY THROUGH TUESDAY/

Main line of snow showers has moved east of the terminals with mainly VFR conditions expected for most of the period. There could be some scattered snow showers lingering this afternoon into early evening. This could briefly bring MVFR restrictions over CNY terminals, but confidence on showers directly impacting terminals is low at this time and therefore not included in the TAF.

West-southwest wind gusts this afternoon are expected to be around 20-25 knots before diminishing this evening. There is a brief period of LLWS at ELM tonight from 06Z to 12Z. Otherwise westerly wind gusts return towards the end of the period.

Outlook...

Friday 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...Winter Storm Watch from late Saturday night through Monday evening for PAZ038>040-043-044-047-048-072. Cold Weather Advisory from 7 PM Friday to 10 AM EST Saturday for PAZ038>040-043-044-047-048-072. NY...Winter Weather Advisory until 1 PM EST this afternoon for NYZ009. Extreme Cold Warning from 7 PM Friday to 10 AM EST Saturday for NYZ009. Extreme Cold Watch from Saturday morning through Saturday afternoon for NYZ009. Winter Storm Watch from late Saturday night through Monday evening for NYZ009-015>018-022>025-036-037-044>046- 055>057-062. Cold Weather Advisory from 7 PM Friday to 10 AM EST Saturday for NYZ015>018-022>025-036-037-044>046-055>057-062.