textproduct: Binghamton

WHAT HAS CHANGED

Light snow and flurries were added to the weather grids through the afternoon for the Twin Tiers and northward. Highest chances early this evening.

KEY MESSAGES

1) Light snow this afternoon with lake effect snow tonight into tomorrow with below average temperatures continuing.

2) A clipper system late in the week and into the weekend will bring a chance for snow as well as a strong arctic front. Below normal temperatures and gusty winds will lead to wind chills well below zero.

DISCUSSION

KEY MESSAGE 1...

Satellite imagery shows a nice shortwave with a small low pressure system passing through the northern Great Lakes. While we do not have our radar this afternoon, the day cloud phase shows that the cloud tops in western NY are glaciating and surface observations as well as webcams show some snow showers have developed with the bit of heating we have had today. Chances of precipitation were increased across the Southern Tier and northward with flurries added for NEPA through this evening. Since these showers look to be diurnally driven, the chances of precipitation were ended shortly after sunset today.

Tonight, once the shortwave is through, 850 mb temperatures fall once again with flow becoming Northwesterly. Conditions are favorable for lake effect snow off of Lake Ontario. Given the increase in ice cover as well as the loss of the upstream connection with the Georgian Bay ice covered now, there is uncertainty in the inland extent of the band. It looks like northern Onondaga county may get 2 to 4 inches of snow over the next 24 hours, but if the extent is greater, then closer to 6 inches is possible.

Headed into later tomorrow and into Thursday, the flow becomes more northerly across Ontario and with the loss of lake fetch, lake effect bands become disorganized and more cellular. Much of northern CNY and the Finger Lakes region will see on and off snow showers with little accumulating snow expected.

KEY MESSAGE 2...

A stronger system moves in Friday into Friday night with a 500 mb shortwave going from positively tilted in the Great Lakes to neutrally tilted as it moves into the Northeast. This shortwave will still be lacking a lot of moisture overall but with strong forcing, there will still be widespread snowfall. With the lack of moisture and the speed of the shortwave, QPF amounts are on the lighter side. Ensemble probabilities of greater than a quarter inch of precipitation is less than 10% for most of the area, outside of the Tug Hill which is closer to 30% chance. Expected snowfall with this event is likely less than 2 inches region wide outside of the tug hill and higher terrain where it could get up to 4 inches.

The main story with this clipper is the arctic air moving in behind it. Luckily the trend has been to a slightly warmer air mass descending out of Canada with 850 temperatures closer to -25C rather than -30C as some of the models were showing earlier in the week and over the weekend. Given the strong cold air advection leading to steep low level lapse rates, some of the higher winds aloft will be able to mix down Friday night into Sunday morning. Winds could gust as high as 40 mph with sustained winds of 15 to 25 mph region wide while temperatures struggle to get out of the single digits through the weekend. With the ice on the Great Lakes, we may not see as much temperature moderation so despite the temperatures aloft being a little warmer than several of the cold snaps over the previous years, the air will not warm as much as it passes over portions of the Great Lakes. Widespread wind chills of -15F to -25F are expected with potential for portions of CNY and higher terrain of the Southern Tier and NEPA seeing closer to -30F.

AVIATION /00Z WEDNESDAY THROUGH SUNDAY/

Some MVFR TEMPO groups this evening for some snow showers working across central New York. Ceilings should lower to MVFR again for all TAF sites but KAVP. Some lifting of the ceilings should occur Wednesday afternoon but they largely looking to stay in the MVFR range.

Outlook...

Wednesday night through Thursday night...Lake effect clouds and snow showers may result in occasional restrictions at all terminals except for KELM and KAVP.

Friday through Friday night...Restrictions likely with widespread snow showers, along with potential snow squalls and/or blowing snow late.

Saturday...Occasional restrictions possible at KSYR and KRME with scattered snow showers. Otherwise, mainly VFR.

BGM WATCHES/WARNINGS/ADVISORIES

PA...None. NY...None.