textproduct: Binghamton

WHAT HAS CHANGED

There is increasing confidence for a round of light to moderate snow tonight, changing to a wintry mix during the day on Tuesday. Winter Weather Advisories may need to be issued later today.

KEY MESSAGES

1) Some lingering lake effect snow showers expected early this morning along the NY Thruway corridor.

2) A clipper system will pass through the area tonight into Tuesday, which will bring light to moderate snow to the area tonight, changing to a wintry mix on Tuesday.

3) Additional clipper systems are possible through the end of the week; a favorable pattern for mixed precipitation events.

DISCUSSION

KEY MESSAGE 1...

While the steadiest lake effect snow is now over, there are still some lingering light to moderate lake effect snow showers along the NY Thruway corridor with west-northwest winds continuing and 850mb temperatures still around -14C. A Winter Weather Advisory remains in effect for Onondaga County until 7AM, although it is possible this could be cancelled early with the bulk of the accumulating snow starting to wind down. By around 12Z/7AM, winds will shift to become more southwesterly, which will allow for any remaining light snow showers or flurries to move to north of the NY Thruway corridor and gradually dissipate.

KEY MESSAGE 2...

A weak clipper system moving through the Northern Great Lakes tonight into Tuesday will bring a warm front into NY and PA. Overrunning precipitation moves in tonight and with plenty of antecedent cold air in place, precipitation type tonight is expected to be entirely snow. However, by daybreak on Tuesday, forecast soundings show a warm nose moving in, which would likely change the snow to a wintry mix of of snow, sleet, and freezing rain, and eventually all rain in the valleys.

The timing of this transition results in a tricky snow accumulation forecast. The best chance for seeing accumulating snow will of course be tonight with the form of precipitation likely remaining all snow. Snow amounts tonight will likely be 1-3 inches for most of the area with locally higher amounts in the upslope areas of Central NY. With there being decent omega through the DGZ and indications there could be a mid-level FGEN band bisecting Central NY, there is certainly a potential for some locations to see some snow amounts a bit higher than currently forecast.

Once precipitation changes to a wintry mix Tuesday morning, while there could be some minor ice accumulation, overall impacts are expected to be limited since this light accumulation would be on top of fresh snow. Eventually, temperatures warm enough by Tuesday afternoon (highs in the mid 30s to lower 40s) to have any lingering showers be mainly in the form of rain or a rain/snow mix.

After coordinating with our surrounding WFOs, it was decided to hold off on any Winter Weather Advisory decisions until the day shift due to the high degree of uncertainty regarding if criteria will even be reached and low confidence in the wintry mix impacts (or if the wintry mix will even occur long enough to cause problems).

KEY MESSAGE 3...

The upper level pattern in the Northern Hemisphere looks to be blocked with 3 large ridges in Western Alaska, the Central U.S., and Northern Europe. This means that we will be stuck on the backside of a trough off of the Eastern U.S. and the Central U.S. ridge leading to plenty of chances of clippers to drive out of the northwest into the Mid Atlantic. Given the amount of warm air in the Central Plains, as well as access to cold air in eastern Canada, the setup is favorable for overrunning mixed precipitation events through the end of the week and into next weekend.

Right now, our official forecast keeps things simple with just rain/snow showers, but additional p-types could be introduced as the week progresses and if confidence increases.

AVIATION /06Z MONDAY THROUGH FRIDAY/

Light lake effect snow continues to fall over ITH and SYR at this hour. Upstream satellite observations show the flow starting to shift to the NE as a ridge builds in from the SW. This will push the band NE into RME tonight and out of ITH in the next hour or two. MVFR conditions are expected at SYR and RME into the morning hours as a cloud deck off the lake hangs around.

VFR conditions expected this morning into the evening hours for all terminals.

Another system will move in later this evening from the west, bringing snow showers that should produce MVFR restrictions at the end of this TAF period. IFR impacts should develop during the overnight hours and into the morning.

Outlook...

Monday night...Snow overspreads the area with IFR restrictions developing late in the overnight hours at all terminals.

Tuesday and Tuesday night...Snow and IFR and lower restrictions expected through the morning hours. Occasional IFR restrictions possible in rain and snow during the afternoon. Restrictions may linger into the overnight hours

Wednesday...Mainly VFR.

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

Friday...Rain and snow showers likely along with associated restrictions.

BGM WATCHES/WARNINGS/ADVISORIES

PA...None. NY...Winter Weather Advisory until 7 AM EST this morning for NYZ018.