textproduct: Binghamton

WHAT HAS CHANGED

Temperatures have warmed above freezing for much of the area this afternoon, with just a few rain showers expected. Winter weather advisories remain in effect for the far eastern and northern portion of our CWA, where additional minor snow and ice accumulations remain possible into tonight. A flood watch has been issued for Steuben County where ice jams could cause localized flooding issues. The strong coastal storm continues to trend north and west closer to our area Sunday into Monday morning. Snow amounts are increasing in the forecast for this time period, especially over northeast PA and the southern Catskills.

KEY MESSAGES

1) An area of low pressure stalls over the Great Lakes region tonight with a stationary front through our region bringing rain and some mixed precipitation to the area.

2) Watching potential for ice jams over the next few days with temperatures remaining at or above freezing with additional rain. Flood watch is in effect for Steuben County until Saturday evening.

3) A strong coastal low will develop to our south late this weekend, tracking northeast toward the 40/70 benchmark by Monday morning. A trough of low pressure will extend northward into our region, bringing periods of snow. Portions of the area (NE PA & southern Catskills) may be more directly impacted by the coastal low.

DISCUSSION

KEY MESSAGE 1... The stationary/warm front is draped over far northeastern portions of our forecast area at this time, and it is not expected to move very much, until a cold front presses in from the west after midnight. Most of Central NY and all of NE PA has warmed up into the mid-30s to mid-40s this afternoon, with scattered rain showers around. A few pockets of freezing rain remain possible over the higher elevations and sheltered valleys of the east-central Catskills into this evening. Also across northern Oneida county a mixture of snow, sleet and freezing rain will continue into tonight. Winter weather advisories remain in effect for these areas into tonight. Additional snow and ice accumulations are expected to be light, with less than 1 inch of snow and just a light glaze of ice...except perhaps 1-3 inches of snow/sleet over northern Oneida. Temperatures tonight gradually fall back into the upper 20s and lowers 30s for most locations.

The frontal system and trough stalls over the area on Saturday, with some lingering snow showers and flurries expected over Central NY, but with really no additional accumulation expected during the day. Temperatures reach the mid-30s to lower 40s, which is close to average for late February.

KEY MESSAGE 2...

Several ice jams have been reported and noted across Steuben County but EMA partners. Temperatures will hold in the mid-40s and above freezing for much of the evening and overnight hours. Additional light rain showers and snow melt will continue to add some water into the rivers and creeks across the area. This will allow the thick ice to continue breaking up and moving. Therefore, we cannot rule out additional ice jams and/or ice james producing flooding issues. The melting processes may slow late tonight and Saturday morning as temperatures dip down around or just below freezing, but as it warms again on Saturday additional ice movement could very well occur.

KEY MESSAGE 3...

Current mid level water vapor imagery shows several players across the US, that will attempt to phase together to potentially produce a large and powerful nor eastern over the region by Sunday into Monday morning. An mid level low is evident across the Central Great Lakes, drifting east with time. A jet streak, with added subtropical moisture is being picked up extending across northern Mexico, into Texas and the lower Mississippi Valley. Another key mid level shortwave is seen moving east across Colorado. This is a complex setup and the latest model guidance is starting to trend toward a stronger and closer to the coast low pressure center late this weekend. The charge was lead by the GFS/GEFS model guidance and now there was a fairly sizable shift NW with the 12z ECMWF and 12z CMC ensemble members this afternoon. The ensemble mean (GEFS/CMC/ECS) is now showing a 984mb low 60-90NM east of Ocean City MD by 1 AM Monday, then moving northeast and deepening to a sub 970mb low near the 40N 70W benchmark Monday morning. An inverted trough will be lingering back across Central PA and Central NY Sunday into Sunday night, coming from the the frontal system that is currently impacting our area. This inverted trough may act as an additional lifting mechanism to produce bands of enhanced snowfall in portions of our forecast area. The exact details, such as track, timing and snow amounts remain uncertain with this coastal system. However, with that said trends are definitely pointing up for an impactful winter storm somewhere across the Mid-Atlantic and Northeastern US. The latest 13z NBM probabilities for greater than 6 inches of snow continue to increase especially across the Poconos and southern Catskills, where chances are up to 50-70% in a few locations. Still, even with this northwest trend in the guidance today, the heaviest snow from this system likely remains east of our CWA.

As mentioned above there is also uncertainty in how the snow and precipitation shield will evolve with this low, as it becomes closed off at 700mb and even 500mb Monday morning. There will be mesoscale banding potential as well, but again, being 48-72 hours out in time is still clouding these specific details. We will continue to very closely monitor model guidance trends in the coming days, and if confidence in warning level snow amounts continues to increase, winter storm watches may be issued for portions of the area.

The timing of this system, based on the latest data looks to be as follows. Some light snow develops along the inverted trough axis and expands over the area during the day on Sunday. The snow could become locally moderate in intensity along the trough axis and/or closer to the coastal low. Temperatures will be in the 30s for most areas, so the snow may not accumulated very effectively in the lower elevations during the midday hours Sunday; thus lowering snow to liquid ratios during this timeframe. Periods of snow then continue to rotate around the strengthening coastal low heading into Sunday night, with specifics still unknown. Temperatures do fall back into the 20s so snow to liquids are likely to increase, closer to 15:1. Northerly winds increase between 10-20 mph with some higher gusts Sunday night into Monday as the coastal low gradually pulls east. Some snow or snow showers look to linger into the day on Monday as colder air aloft (-10C at 850mb) filters into the region.

AVIATION /20Z FRIDAY THROUGH WEDNESDAY/

Lingering light rain will gradually taper off this afternoon before a quick hit of another round of rain/snow mix between 22Z and 02Z this evening and then light lake enhanced snow showers into the favored areas southeast of Lake Ontario into Saturday morning. Gusty southeast winds this afternoon will veer to the west/sw tonight and eventually to the west/nw Sat morning. Gusts to 20 kt this afternoon are possible and gusts tonight and Saturday could increase up to 15 kt at times.

Ceilings will hover around MVFR/fuel alternate required through this evening, with a slight chance of dipping to IFR as an area of rain/snow mix moves through. Flight conditions improve slightly after the precipitation moves through before dropping back to fuel alt/IFR after 08-09Z...and persisting through most of the Saturday morning hours.

Outlook...

Saturday afternoon...Isolated to scattered rain/snow showers mainly RME,SYR,ITH and BGM. Confidence is low on restrictions with the uncertainty in timing.

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

Monday...Mainly VFR; low chance of light snow showers. Low to moderate confidence.

Tuesday...Mainly VFR. High confidence.

Wednesday...Restrictions possible as a clipper system moves through the region. Confidence is low.

BGM WATCHES/WARNINGS/ADVISORIES

PA...None. NY...Winter Weather Advisory until 7 AM EST Saturday for NYZ009. Flood Watch through Saturday evening for NYZ022. Winter Weather Advisory until 1 AM EST Saturday for NYZ037-046- 057-062.