textproduct: Binghamton

WHAT HAS CHANGED

Winter Storm Watch issued for Otsego County. Winter Storm Watches upgraded to warnings for Luzerne, Lackawanna, Southern Wayne, Pike, and Sullivan Counties. Snowfall totals for Sunday's system were updated with a slight more northern extent. Temperatures were lowered on Sunday. Winds and gusts were increased during the storm so blowing snow was added to the forecast.

KEY MESSAGES

1) Lake enhanced flurries and freezing drizzle possible before winter storm. Flood Watches also remain in effect for Steuben and Tompkins until this evening.

2) A Nor'east will develop to our south early Sunday and moves up the coast through Sunday night bringing accumulating snowfall to the region. Lake effect snow develops behind this departing system with additional snowfall for portions of CNY early next week.

3) Active pattern continues next week with temperatures warming back up to near normal.

DISCUSSION

KEY MESSAGE 1...

A weak wave remains stretched across the region and northwesterly flow are supporting some areas of light flurries and freezing drizzle. This wave will lift north and flow becomes more southwesterly tonight, so this precipitation will gradually come to an end late this evening. Little to no snow and ice accumulations are expected but with some slippery spots on untreated surfaces will be possible.

Another concern is the potential for flooding due to ice jams in Steuben and Tompkins County. Recent updates from local officials have mentioned some minor localized flooding in open fields but fortunately, no residential or business properties are. Still, we will continue to monitor these situations for any changes that may require an extension of these watches that are set to expire later this evening or upgrade to warnings.

KEY MESSAGE 2...

The main concern in the forecast period is the Nor'easter that will impact the region Sunday into Monday. A low pressure system will develop well south of the region tonight. As it moves off land and begins to strengthen, a low over the Great Lakes weakens. Moisture from these two systems will support scattered snow showers ahead of approaching coastal low. A few areas where temperatures climb into the mid 30s could see rain/snow mix or rain briefly during the afternoon. Snow will then begin to become more widespread north to south Sunday night as the low moves up the coast and continues to strengthen. The merger of these two lows may create a narrow axis of heavier snow over west-central NY late Sunday. With a strong pressure gradient extending as far back as the Mississippi Valley, winds will also pick up overnight, resulting in blowing snow. Gusts up to 40 mph will be possible.

Snow gradually ends west to east as the moves along the New England coast Monday. Models are showing some FGEN banding Monday suggesting that there will be potential for some locations to observe the highest snowfall rates of the event if snow lingers long enough As snow ends with this system, another wave dips south and northwest flow over Lake Ontario will enhance additional snow showers over central NY Monday night and into Tuesday. Additional snowfall accumulations are expected.

This is a challenging forecast even being within 24 hours of when the first snowflakes are expected to fall. Models are in better agreement with the location and strength of the low but do differ on the extent of snow. This then leads to a wide range of snowfall amounts and uncertainty where the sharp cutoff will be. A blend of NBM and WPC QPF was used for Sunday through Monday. WPC was not as aggressive as far north as the NBM and even accounted for that early axis of snow over west-central NY as the two lows merge, though some manual edits were made to that feature to lower totals for now. WPC SLRs were more reasonable compared to NBM. The mild, moist conditions should keep SLRs in the range of 10-15:1. As a result, there were some significant changes to snowfall and the northern extent was increased. Due to this, Otsego County was added to the Winter Storm Watch though snowfall totals are on the lower end of warning criteria. Then the watch was upgraded to a warning for the southern counties in our CWA as that is where confidence is highest that at least 6-7 inches will fall. Further north, we hang onto watches for another forecast cycle as these could end up being either warnings or advisories.

Solutions such as the GFS and NAM have a wider QPF footprint compared to solutions similar to the ECMWF and CMC. Given the uncertainties, this forecast continues to favor blended guidance and does not lean in the direction of any particular solution. With that said, snowfall amounts are likely to change again, so monitor the forecast for additional updates.

KEY MESSAGE 3...

The pattern remains quite active through the rest of the week. A clipper system will move through midweek. Conditions will be cold enough for mainly just snow across the region. Enough moisture will be present for there to be additional snowfall accumulations with this system, though totals should be light. Then a low will pass just to the south Thursday night into Friday. A warm front associated with this system may push north into the region late Thursday with milder air possible over the southern half of the region. Precipitation would initially be rain but then would become snow as colder air filters in. While there is some uncertainty with this system, guidance has high pressure building in on Friday and sticking around into Saturday.

AVIATION /00Z SUNDAY THROUGH THURSDAY/

A persistent deck of low clouds continues to bring at least widespread MVFR ceiling restrictions this evening, with some light snow, flurries and patchy freezing drizzle also around the area. This trend will continue through the overnight, although there could be some tempo IFR CIGs at RME through late evening (04z)

Light snow from a developing coastal storm/Nor'easter is expected to move in late tonight/early Sunday morning along an inverted trough axis and is expected to persist through the day on Sunday. While the steadiest/heaviest snow will likely hold off until Sunday night and Monday AM, IFR visby restrictions will still be possible at times through the day on Sunday. More widespread IFR ceilings will also be moving in around the same time.

Surface winds will be light and variable under 5 kts overnight, turning easterly at 5-15 kts Sunday into Sunday evening.

Outlook...

Sunday night...Snow and associated restrictions, especially for KAVP and KBGM. Uncertainty regarding how far northwest the heavier snow will get, so lower confidence across the rest of the Central NY terminals. North winds increase overnight 8-15 kts, with gust 20-30 kts late (BGM and AVP)

Monday...Restrictions likely with lingering snow bands and blowing snow; especially in the morning. Gradual improvement through the afternoon hours.

Tuesday...Mainly VFR.

Wednesday through Thursday...Occasional restrictions possible with light rain/snow.

BGM WATCHES/WARNINGS/ADVISORIES

PA...Winter Storm Watch from Sunday afternoon through Monday evening for PAZ039-040-043. Winter Storm Warning from 1 PM Sunday to 7 PM EST Monday for PAZ044-047-048-072. NY...Flood Watch until 8 PM EST this evening for NYZ022-025. Winter Storm Watch from Sunday afternoon through Monday evening for NYZ046-057. Winter Storm Warning from 1 PM Sunday to 7 PM EST Monday for NYZ062.