textproduct: Binghamton

WHAT HAS CHANGED

With temperatures above freezing in parts of the Southern Tier and into the Finger Lakes, freezing rain was removed from the grids. Ice accumulations were lowered along I-81 corridor with a smaller window of below freezing temperatures. Ice accumulations were increased on the eastern slopes and summits of Catskills and eastern Poconos.

KEY MESSAGES

1) An area of low pressure moves into the Great Lakes region today with a warm front lifting through our region bringing rain and mixed precipitation into tomorrow morning.

2) While a coastal low stays to our south late this weekend, a trough of low pressure will extend northward into our region, bringing some light snow.

3) Watching potential for ice jams over the next few days with temperatures remaining at or above freezing with additional rain.

DISCUSSION

KEY MESSAGE 1...

Temperatures this evening have been staying a little warmer than modeled as thick cloud cover has prevented cooling. Dew points have been falling due to some downslope drying in the SE winds in the western Catskills and Twin Tiers region. In the Finger Lakes and Chemung river basin, dew points and temperatures are above freezing. Precipitation will be moving in by around sunrise and with the warmer temperatures in western NEPA up into the Finger Lakes, freezing rain was taken out of the grids. For the I-81 corridor and eastward, the dry air in place will help the air temperature wetbulb down below freezing at least briefly before warming up at precipitation onset.

Forecast soundings have a pretty shallow cold inversion at the surface for the Catskills and east, with east winds so as the rainfall intensifies later this morning, that will mix out that cold air fairly quickly west of the Catskills and Poconos. East of the Catskills and Poconos, those east and southeast winds will help trap cold air in place so areas in Sullivan County down into Pike and Wayne may see freezing rain for much of the day. The eastern facing slopes and summits of the Catskills in Delaware and Otsego counties also are favorable for a longer duration freezing rain event. QPF amounts look to be a half inch or less so no significant ice accumulation is expected. Summits of the Catskills may get up to a quarter inch of ice with lower slopes closer to a tenth of an inch.

Headed north into the Mohawk Valley, forecast soundings out of Utica and up into Rome still look marginal with surface temperatures right around freezing. Given the east winds, it may be just enough to wobble temperatures up and down. Heavier periods of precipitation would be able to mix down the warmer air and pop temperatures above freezing but between heavier bands, some freezing drizzle or light freezing rain is possible. Snow is looking unlikely as temperatures aloft get above freezing right around precipitation onset. Still left some snow in the grids just in case there can be some cooling of the atmospheric column during heavier precipitation to briefly mix in some wet snow.

Late this afternoon and this evening, the surface low in the Great Lakes begins to occlude as a new low forms off the Atlantic coast. Once the surface low off the coast begins to deepen in the late afternoon, cold air advection and dynamic cooling drops temperatures below freezing with precipitation transitioning to snow region wide. Given that the forcing quickly leaves as the deepening coastal low races east leaving behind an elongated trough of low pressure, till given the subtle rising motion and moisture in place under this trough, some light snow or flurries will continue into Saturday morning.

KEY MESSAGE 2...

While a strong coastal low will form this weekend, the placement of the low will likely remain to our south. The trough of low pressure left behind by our current low will connect with this low and help snow redevelop over our region as the low deepens off of the Carolinas and Virginia coast. Given the lack of strong lift, snow will not be heavy but broad weak lift will likely lead to a period of light, persistent snow from late Sunday into Monday. While rates will not be high, the duration of the snow may result in near advisory criteria amounts.

KEY MESSAGE 3...

With the above freezing temperatures and rain today, the threat remains for ice jams. NOHRSC analysis shows the snowpack temperature is up to 32 degrees for much of the Finger Lakes into NEPA so any rain and snowmelt will be running into the streams and rivers. River ice is also estimated to be around a foot on some of the main stems, so as the water rises and the ice breaks up, there is ice jam potential anywhere there is a sharp bend or a narrowing of a river or stream. Areas in the Catskills and eastern Poconos don't have as high of an ice jam threat as the temperatures will struggle to get much above freezing preventing much snow melt.

AVIATION /06Z FRIDAY THROUGH TUESDAY/

A mix of MVFR to IFR restrictions are expected to continue before a system lifts a warm front through the area from southwest to northeast around 12z, bringing widespread precipitation, and worsening conditions.

With current overnight temperatures remaining above freezing at all terminals, precipitation will mainly fall as rain, with exception of RME. Temperatures through the profile indicate the highest chances for freezing rain, so it was kept in the 06z TAF package. RME will also likely be the only terminal where we'll see precipitation transition to wet snow after 00Z tomorrow.

Wind shear has been added to AVP, but could be added to other terminals with the 12z package. Highest confidence was only at AVP at this time.

Outlook...

Friday afternoon...Lingering showers, mainly in the form of rain, are expected to keep restrictions in place.

Friday night...Isolated to scattered rain and snow showers and associated restrictions.

Saturday...Isolated to scattered rain/snow showers. Confidence is low on restrictions with the uncertainty in timing and coverage.

Sunday...Potential coastal low could impact central NY and NE PA Sunday with restrictions from snow showers. Confidence is low.

Monday...Mainly VFR; low chance of light snow showers.

Tuesday...Mainly VFR.

BGM WATCHES/WARNINGS/ADVISORIES

PA...Winter Weather Advisory from 5 AM early this morning to noon EST today for PAZ038>040-043-044-047-048-072. NY...Winter Weather Advisory from 7 AM this morning to 7 AM EST Saturday for NYZ009. Winter Weather Advisory from 5 AM early this morning to noon EST today for NYZ036-044-045-055-056. Winter Weather Advisory from 6 AM this morning to 1 AM EST Saturday for NYZ037-046-057-062.