textproduct: Binghamton

WHAT HAS CHANGED

Extreme Cold Watch was continued. Confidence location of coldest wind chills not high enough to issue headlines at this time.

KEY MESSAGES

1) Lake effect snow diminishes by late afternoon.

2) A clipper system will bring widespread light snow Friday. Behind this system, an arctic frontal boundary will bring brutally cold conditions this weekend.

3) Temperatures begin to trend warmer next week with potential for closer to normal conditions.

DISCUSSION

KEY MESSAGE 1...

Light lake effect snow continues across CNY this afternoon. Snow is starting to retreat to the north as a ridge builds in from the SW and the winds shift to more westerly. Snow should be completely over by mid afternoon. Temps this afternoon will climb into the low to mid 20s across the region.

KEY MESSAGE 2...

The main impactful weather event will be this weekend as a clipper system moves through on Friday, followed by brutally cold conditions into Monday.

A clipper system will drop into the Great Lakes region Friday morning and quickly dive to the SE through the day. Snow showers should move in from the WNW Friday afternoon, becoming more widespread by the early evening into the overnight hours. Accumulations look to be light, with 1-3 inches expected region wide. The Finger Lakes could see around 4 inches as some lake moisture could enhances the snow totals in the area. Snow is expected to be very light and fluffy. An arctic front will accompany this clipper system, pushing into the area just after midnight. Temps will quickly fall from the low 20s around midnight to near 0 by 6am. The pressure change across this front is very strong, leading to strong and gusty winds accompanying this arctic airmass. NW winds of 15 to 30mph with gusts up to 40mph are forecast to fill in across the area behind the front late Friday night into Saturday evening. Anafrontal snow is expected to be present into the early morning hours, followed by lake effect snow showers. The earlier snowfall combined with the aforementioned snow will lead to widespread blowing snow into Sunday, causing visibility to quickly drop and roads becoming snow covered. With the brutally cold temperatures, road treatments do not work very effectively so travel will be hazardous, especially in some areas where blowing snow can be an issue.

Speaking of brutally cold, temperatures on Saturday will remain in the low single digits and with the strong winds expected, wind chills will be in the -15F to -25F range across the area during the day. Saturday night will see the coldest lows of the weekend, with near 0F to -18F lows across the region. Combined with active NW winds, wind chills will fall into the -25F to -35F range east of I-81 and -15F to -25F west of I-81. The Extreme Cold Watch was not upgraded as there is still some uncertainty as to how far west the extreme cold will get. This should be better resolved during the next forecast update. Sunday will remain brutally cold in the morning. Winds lighten up during the afternoon as a surface high builds in from the west, but with temps remaining in the single digits, wind chills will still be in the -5F to -15F range through the Sunday and into Monday morning. The coldest air retreats north on Monday, with highs in the mid teens and wind chills in the positive single digits.

Light Finger Lake effect snow is expected to remain through the weekend with mostly aligned NW flow through the lower portion of the atmosphere. The saturated layer of the atmosphere will be too cold for the DGZ, so any snow that falls should not be in dendrites, but plates or needles. This would limit accumulations, even though no much is expected at this time. Another 0.5 to 2 inches could fall south and east of the Finger Lakes through Sunday evening.

KEY MESSAGE 3...

Uncertainty remains as to how the overall pattern will play out next week. There have been signals for a slight warm up by mid week but guidance is mixed in how the pattern evolves. The ridge that has been planted out west over the past several weeks looks to eject eastward as a low south of Alaska guides the jet stream into the west coast of the US. Originally, this ridge was very amplified and brought above freezing temps to the area mid-week, but that trend has backed off a little bit. GFS has flattened the ridge, allowing cold air to remain overhead and temps only climbing into the mid to upper 20s. The ECMWF has a more amplified ridge which allows temps in the mid 30s to move in by mid week. Either way, much warmer temperatures will be welcome'd compared to what we have seen over the past several weeks.

AVIATION /00Z FRIDAY THROUGH TUESDAY/

VFR conditions are expected to persist through tonight and at least until 18Z tomorrow. The next system starts to move in from the west around or just after 18Z with clouds thickening and ceilings beginning to lower. Winds remain light and variable through at least the next 24 hours.

Outlook...

Friday afternoon through Friday night...Restrictions likely with snow showers, along with a low potential for snow squalls and/or blowing snow as winds really start to gust late Friday night.

Saturday through Sunday morning...Strong winds with occasional ceiling restrictions at all terminals except for KELM and KAVP.

Sunday afternoon through Tuesday...Mainly VFR.

BGM WATCHES/WARNINGS/ADVISORIES

PA...Extreme Cold Watch from late Friday night through Sunday afternoon for PAZ038>040-043-044-047-048-072. NY...Extreme Cold Watch from late Friday night through Sunday afternoon for NYZ009-015>018-022>025-036-037-044>046- 055>057-062.