textproduct: Binghamton

WHAT HAS CHANGED

No big changes from previous forecast; adjusted the timing of precipitation transition from snow to rain Christmas Day.

KEY MESSAGES

- 1) Rising rivers will continue into tomorrow. Ice movement still possible and we will continue to monitor for potential ice jams.

- 2) A moisture starved cold front moves through tomorrow, kicking off lake effect snow across CNY with 1-3 inches possible through tomorrow night.

- 3) Several systems to move through during the holiday travel period next week.

DISCUSSION

KEY MESSAGE 1... Rising rivers will continue into tomorrow. Ice movement still possible and we will continue to monitor for potential ice jams.

KEY MESSAGE 1 DESCRIPTION... Runoff from rainfall and melting snow from yesterday will continue to cause the main stem North Branch Susquehanna and Upper Delaware rivers to rise into tomorrow. Flow increases downstream are expected to peak tomorrow afternoon and are still expected to be sufficient enough to break up and move the established ice cover that has developed in some stretches of these rivers. Monitoring of sensitive and restrictive areas along the rivers for the possibility of ice jam formation and localized flooding will be needed through the weekend. Report active flooding to the National Weather Service as soon as possible.

KEY MESSAGE 2... A moisture starved cold front moves through tomorrow, kicking off lake effect snow across CNY with 1-3 inches possible through tomorrow night.

KEY MESSAGE 2 DESCRIPTION... A system to the north of the area will slide eastward early morning tomorrow, pushing a cold Canadian airmass into the region. With mostly zonal flow ahead of this system, there will be no access to moisture from the Gulf or Atlantic, so the front itself should not produce much precipitation. Behind the front, 850mb temps will fall to below -10 C during the day, and a ridge building into the central US, which will allow winds in the low and mid atmosphere to line up nicely out of the NW, and with upstream connection from Lake Huron and the Georgian Bay, lake effect snow is expected to develop for northern Central NY. Currently, 1-3 inches are forecast to fall over this area into tomorrow night. The aforementioned ridge should continue to build to the east-northeast into our area and cut off the lake effect by Monday morning. KEY MESSAGE 3... Several systems to move through during the holiday travel period next week.

KEY MESSAGE 3 DESCRIPTION... With a strong ridge sitting in place in the central US, a series of shortwaves will pass through the area through the upcoming week. The first shortwave should pass to the north Tuesday, with snow in the morning changing to a rain/snow mix by the afternoon as warmer air works its way in from the west.

Confidence for a shortwave moving through the area overnight Christmas Eve and into Christmas Day is increasing; precipitation could start as snow and change to rain as the morning progresses as warm air advection pushes its way into the area. With this being the busiest time of year for travel, we will be monitoring how this develops very closely for any potential for freezing rain since there is a low probability. Christmas Day is currently tracking to be pretty warm over the area, with highs in the low 40s. This warm air is currently modeled to stay around when the next clipper system moves in on Friday, bringing mostly rain to the area.

AVIATION /18Z SATURDAY THROUGH THURSDAY/

MVFR ceiling restrictions are expected to break over the next hour or so around KRME, otherwise, VFR conditions are expected for much of the TAF period. Some lower ceilings are expected late in forecast period around KRME and KSYR as lake effect snow takes shape downwind of Lake Ontario. Some light snow is possible at KRME prior to 18Z Sunday, but snow is expected to hold off until just after this at KSYR. While ceilings do lower at the rest of the terminals, VFR conditions are expected through 18Z Sunday.

Southerly winds are expected to become southwest later tonight, and then westerly by mid-to-late morning tomorrow with wind gusts of 20 to 25 knots developing. Southwesterly LLWS around 40 to locally 45 knots is also expected to develop this evening at all terminals from west to east and then start to dissipate between 06Z and 08Z.

Outlook...

Sunday late afternoon through Sunday night...Scattered snow showers across Central NY with occasional restrictions possible, especially at KSYR and KRME.

Monday...Mainly VFR.

Tuesday into Tuesday night...Occasional restrictions possible in scattered rain and snow showers.

Wednesday...Mainly VFR.

Thursday...A low chance of rain and snow showers and associated restrictions.

BGM WATCHES/WARNINGS/ADVISORIES

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