textproduct: Binghamton

WHAT HAS CHANGED

Changed temperatures slightly tomorrow to cool them as models wanted to warm temps mid afternoon but with precipitation and clouds that is unlikely. Slight increase in snow at higher elevations of the Catskills and Poconos tomorrow night into Friday.

KEY MESSAGES

1) Area of low pressure moves through tonight into Friday bringing rain initially with a transition of snow late Thursday into Friday.

2) Below average temperatures and on and off lake effect snow showers this weekend into Monday.

3) Upper level ridging builds back in next week with temperatures gradually warming back up.

DISCUSSION

KEY MESSAGE 1...

High clouds are moving in as an area of low pressure deepens in the Southern Great Lakes region. Water vapor imagery shows a healthy baroclinic leaf expanding across the Ohio River Valley along with deep convection around the center of the low in central Illinois could signify that the low is deepening a little faster than models show. If it is , it likely wont affect our forecast too much outside of some heavier rain tonight into tomorrow. Cold air still lags behind the heavier precipitation with 850 mb temperatures not falling to -2C to -3C until late tomorrow afternoon into the early evening. That is when the transition to snow would begin from higher elevations and eventually to valley floors by Friday morning. There could be a few higher elevated areas above 2000 feet in the Catskills that see 4 or more inches of snow. If the cold air can filter in faster or precipitation lingers longer, then higher accumulations could occur at lower elevations and an advisory may be needed but too much uncertainty on the west side of the Catskills right now. Higher elevations of NEPA may also see some locally higher amounts, especially in Wayne and Pike county though the Wyoming Valley will see mostly rain and a brief transition to some wet flakes before the precipitation ends.

KEY MESSAGE 2...

Behind the departing low, 850 mb temperatures fall below -5C, and with warm lakes, lake effect precipitation will likely form and linger Friday into Saturday. Forecast soundings near the lakes and at lower elevations like the I-90 corridor may be too warm so a rain or rain snow mix is more likely. A brief period of snow is possible overnight at lower elevations though accumulations would be limited to elevated surfaces. In the hills south of the Thruway and in the Tug Hill, above 1000 feet or so, precipitation Friday into Saturday looks to be predominantly snow. Given the early season and instability both over the lake and warm ground, organized lake effect bands dont look likely so widespread on and off showers are expected. This will keep snow accumulations limited to a slushy half inch to inch on mainly elevated surfaces. Roads may become briefly covered if there is a heavy enough snow shower to pass through. These snow showers will struggle to make it much south of the Southern Tier.

KEY MESSAGE 3...

The pattern Tuesday and onwards looks to take on the same pattern that we have been seeing the last few weeks. Upper level ridging with high pressure centered over the Southeast US keeping off shore flow and preventing much moisture return. Skies clear out with more sun but with the much shorter days and low angle, it is going to be hard to get back up into the 60s but could happen towards late week.

AVIATION /18Z WEDNESDAY THROUGH MONDAY/

Conditions will be VFR through today and this evening, but will deteriorate overnight into Thursday morning. Rain will move in from the west late tonight and spread eastward after midnight. MVFR ceilings and visibilities and eventually IFR conditions Thursday morning will come with the rain.

Finally, there will also be a chance for some low level wind shear as the rain pushes in for AVP as an area of stronger winds aloft punch into NE PA. However, this area will likely exit the region around sunrise tomorrow morning.

Outlook...

Thursday...Showers and associated restrictions possible.

Friday through Saturday...A mix of rain/snow showers possible and associated restrictions.

Sunday...Perhaps a few lingering showers, otherwise mainly VFR expected.

BGM WATCHES/WARNINGS/ADVISORIES

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