textproduct: Binghamton

WHAT HAS CHANGED

A slight trend north with coastal low track brings some higher PoPs into the Poconos and possibly 1 to 2 inches of snow.

KEY MESSAGES

1) Coastal low will either be a near miss or just graze portions of the area with light snow.

2) Temperatures will trend warmer through early to midweek, but then trend cooler toward the end of next week. A system moves through Wednesday with rain, snow and a wintry mix possible.

DISCUSSION

KEY MESSAGE 1...

As has been the case all winter long, models continue to have a hard time adjusting with a transition to a zonal flow pattern. This has led to a lot of uncertainty to the mid to long range forecast (Days 3-7). This next coastal system is no different, and now that we are within 36 hours, we have seen the forecast track of the coastal low shift northward. However, it should be noted that just 24 hours ago, this system was a complete miss for our area, with possibly just a few light snow showers with the passing northern stream shortwave.

That northern stream wave came ashore the Washington coast yesterday evening, so for the first time, weather models can actually get some sampled upper air sounding data on it. This wave will race across the CONUS over the next 24 hours and now phase with our southern system and develop a stronger coastal low along the Mid Atlantic Coast tomorrow night. The timing of the northern stream wave and the amplitude will eventually determine exactly where this coastal low develops and then tracks. Still, at this time, even with the storm shifting northward, it is still a near miss for our area, with a 1 to 3 inch snow for the Poconos not out of the question and a coating of light snow as far north as the Twin Tiers. At this time, the thinking is that any further shift north will be slight, if at all, being we are now just 36 hours out. This is because we are getting good sampling into the models now with the wave coming ashore and the 12Z guidance has initialized well with the placement of the ingredients at play. NBM is lagging behind with this shift northward, so leaned on current 12Z deterministic and ensemble models for the forecast. Decided to bump up PoPs from just a slight chance to now likely and increased snowfall totals across NE PA into the Poconos and southern Catskills. Still looking at amounts below advisory criteria, but we could see totals approach advisory criteria in the Poconos if any further north movement is noted.

KEY MESSAGE 2...

Made very little changes to the mid week system at this time and there remains some uncertainty amongst the models.

Previous Discussion... Temperatures will trend warmer through midweek, but how much so remains somewhat uncertain. While it initially looked like a ridge would set up over part of eastern CONUS, models are trending to a more zonal pattern. This would favor cooler air occasionally dipping back south over parts or all of the region. With that said, Monday is still on track to reach the low to mid-40s and Tuesday will be well into the 40s and perhaps even around 50 in the valleys of the Southern Tier and NE PA. Skies will be partly sunny both days, with dry weather expected. Overnight lows still look to dip down into the upper 20s to low 30s for most locations, which will slow the snow melt overnight and in the early morning.

Then midweek, a low moves across the Midwest with a frontal boundary extending well east over our area. There remains uncertainties with this system, though depending on the where the front sets up, this would be favorable for a wintry mix or snow that could possibly include localized freezing rain. The 12z ECMWF continues to be much colder and snowier with the Wednesday system compared to the 12z GFS and 12z CMC model guidance. The official forecast follows the ensemble/NBM guidance at this point in time, to account for uncertainty in temperatures and precipitation type with this system.

Behind this system, colder air dips south as temperatures trend slightly cooler from the peak warmth earlier in the week.

As conditions warm, we will need to keep a close eye on the rivers and streams. Warming temperatures will help melt snow but of there is any rain as well, there could be enough runoff to dislodge ice leading to additional ice jams.

AVIATION /18Z SATURDAY THROUGH THURSDAY/

Northwest flow keeps MVFR/Fuel Alt ceilings across central NY with a brief window of VFR possible at ELM and BGM early evening. MVFR and Fuel Alt are expected to persist overnight. As weak high pressure moves overhead, trapped low level moisture under a subsidence inversion may allow ceilings to lower to IFR across CNY. Confidence in the IFR remains low, so tempo groups were included to indicate the potential timing. Otherwise AVP es expected to remain VFR through the TAF period.

Outlook...

Sunday...Mainly VFR.

Sunday night... Weak clipper system could bring snow showers with associated restrictions.

Monday through Wednesday...Mainly VFR, possible restrictions late Tuesday night into Wednesday with rain or wintry mix.

Thursday...Restrictions possible as low pressure systems passes south of the region.

BGM WATCHES/WARNINGS/ADVISORIES

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