textproduct: Binghamton

WHAT HAS CHANGED

Snow chances have been expanded across CNY this afternoon as light lake effect streamers are moving over the area and are expected to continue into the evening. The Cold Weather Advisory has been extended until 1pm Tuesday given the expected cold temperatures in place and increasing winds that should allow wind chill criteria to be met until the early afternoon.

KEY MESSAGES

1) Very cold temperatures and wind chills expected tonight. A Cold Weather Advisory is in effect for NEPA and Steuben County.

2) Light lake effect snow showers expected thru most of the week, mostly impacting areas north of the Southern Tier.

2) An arctic blast will bring very cold temperatures and wind chills to the region Thursday into Saturday.

DISCUSSION

KEY MESSAGE 1...

A reinforcing shot of cold air will filter in from the NW this afternoon as Sunday's storm system moves off to the NE. A shortwave axis currently over western NY will slide east through the afternoon hours, allowing NW flow to develop across the area and cold Canadian air to filter in by late afternoon. Current temps in the mid to upper teens will fall into the low 10s to upper single digits by 6pm. Winds will be active tonight as isobars on the west side of the transiting shortwave stack up with a ridge building in behind it from the SW. Expected 5-10mph winds will produce wind chills in the -5F to -20F range across the region. Steuben county should see the coldest wind chills with stronger winds across the higher terrain. A Cold Weather Advisory has been issued for Steuben County in NY and all of NEPA. All of NY will see negative wind chills but we are not expecting it to be cold enough to meet criteria for an advisory.

KEY MESSAGE 2...

To go along with the very cold temperatures tonight, lake effect snow is expected to develop this afternoon into Tuesday. Currently, a narrow band of snow is developing along the southern shore of Lake Ontario as we are seeing some wind convergence along this region. This band is expected to stay across northern Onondaga into Oneida county through the evening. Lake effect streamers are also developing across CNY into NEPA this afternoon thanks to some very weak CAPE at the surface and enhanced moisture from the Finger Lakes. A quick burst of moderate snow will be possible under one of these heavier streamers. Accumulations under an inch are expected.

A ridge will build in from the SW later this evening, which should allow the Ontario band and lake streamers to dissipate. Some isentropic uplift is expected along the leading edge of the ridge as some slightly colder temperatures will accompany it. This will generate a band of lake snow that should push through the northern Finger Lakes and north of Oneida county during the overnight hours. This band is expected to remain north of the area through Tuesday afternoon. Total snowfall accumulations through Tuesday morning look to be in the trace to an inch across much of the Finger Lakes, Southern Tier and into the Catskills and NEPA. 2-4 inches is expected across Onondaga, Madison and western northern Oneida county. NW Onondaga county should see the higher end of the range.

A shortwave will traverse the region on Tuesday, allowing for some more widespread snow to develop, especially east of the Finger Lakes. Once this shortwave passes, flow becomes WNWerly again and lake effect snow will push into Oneida, Madison and Onondaga counties on Tuesday night. This incursion south will be short lived as another weak surface ridge will build in ahead of a stronger shortwave, switching flow to more WSWerly and push the band north of the area once again.

A stronger shortwave will move through the area Wednesday night into Thursday, bringing NW flow and more lake effect snow showers thru Friday.

Key Message #3

Another arctic blast of cold air is expected to accompany the aforementioned shortwave passing through the area at the end of the week. A very positively tilted trough is expected to push through from the north at the end of the week, sometime on Thursday to early Friday, dragging -20C to -25C 850mb air into the region. Lows in the -0s Thursday night will only climb into the single digits on Friday. With winds remaining active through this period, wind chills are expected to remain below 0 for much of the area from Thursday night into Saturday. While the timing of the coldest weather is still somewhat uncertain as the speed of the trough could change, he coldest weather is currently expected to be Thursday night into Friday morning, with wind chills in the -10F to -25F area wide.

AVIATION /18Z MONDAY THROUGH SATURDAY/

MVFR ceilings should slowly lift by tonight with the exception of KRME and KSYR. Some light lake effect snow showers are likely to develop by this evening with a fairly high potential for IFR restrictions this evening at KSYR. Currently most of this activity looks to stay west of KRME. A few wind gusts may approach 20 knots from the west this afternoon, winds shift overnight and a few stronger southwest wind gusts can not be ruled out Tuesday.

Outlook...

Tuesday night thru Saturday... A few rounds of light snow showers with the potential for off and on lake effect snow showers at KRME and KSYR. Occasional restrictions likely.

BGM WATCHES/WARNINGS/ADVISORIES

PA...Cold Weather Advisory from 7 PM this evening to 1 PM EST Tuesday for PAZ038>040-043-044-047-048-072. NY...Cold Weather Advisory from 10 PM this evening to 1 PM EST Tuesday for NYZ022.