textproduct: Binghamton

WHAT HAS CHANGED

No significant changes made to the forecast. Only change was to add mention of snow showers off of Lake Ontario Monday night.

KEY MESSAGES

1) Showers and thunderstorms rolling across the region today with a few possibly becoming strong to severe and brief heavy rain possible.

2) Cold air arriving tonight will cause a period of freezing drizzle and light lake effect flurries into the Finger Lakes into Monday.

3) Gusty northwest winds Monday afternoon and light lake effect snow showers off of Lake Ontario Monday night with only minor amounts.

4) Next round of rain expected Thursday and Friday with another cold weekend and light snow possible on Saturday.

DISCUSSION

KEY MESSAGE 1...

Warm front has lifted northward across central NY this afternoon, but there is a minimal amount of mixing of the warm air down to the surface as of 1 PM across portions of central NY. Multiple waves have been able to ride east along the warm front this morning, which have kept a nearly continuous stream of rain showers going from wrn NY east across most of the state. A couple weak storm have attempted to move along the southern tier, but there has not been enough instability to keep them going.

Areas to the south, into northeast PA, have managed to experience a bit more clearing and produce temperature into the upper 50s and lower 60s. The elongated surface trough is extending from northern OH into wrn NY this afternoon and will move to the east/se through the rest of the day. The upper level dynamics are fairly weak, with the most notable feature being a weak embedded short wave rolling across NY and a 120 kt jet streak over the northern Great Lakes.

We are still expecting convection to initiate along or just south of the NY/PA border later this afternoon and progress to the southeast across mainly northeast PA into the early evening hours. There is still some uncertainty with regard to the storm mode and intensity, along with potential impacts, but the guidance and mesoanalysis continue to point at storms mostly initiating above the boundary layer and then possibly becoming rooted in the near surface layer as they grow upstream to the southeast.

The most likely time for initiating looks to be around 3-4 PM...with storms tracking to the e/se through around 7-8 PM before exiting our forecast area. There is expected to be a layer of instability aloft along with some steeper mid level lapse rates...and cold air aloft that could allow for the primary threat to be hail. However, as the storms grow and potentially tap into the surface instability, there is likely more of a threat of gusty winds later in the event.

We will also need to watch the threat for heavy rain and possibly some isolated flooding issue...especially in the urban areas of the Wyoming Valley. The E-W orientation of the surface trough and deeper moisture riding up from the southwest along this feature could allow for storms and heavy rain to train briefly over the same areas before the entire system moves out. Will need to watch how the convection evolves and how quickly/slowly the broader system exits this evening.

KEY MESSAGE 2...

Behind the departing low pressure system a cold air mass will move in quickly and allow the rain to change over to mix of snow and freezing drizzle late tonight and early Monday morning. The cold air is expected to undercut the exiting warm layer aloft during this time and allow favorable thermal profiles for light freezing rain/drizzle and snow before the slightly drier air moves in by late Monday morning. No significant icing or snow accumulations are expected tonight.

KEY MESSAGE 3...

As the 850mb low moves off the coast and the ridge to the west builds quickly east a favorable tight pressure gradient will set up over the region. This will cause gusty northwest winds up to 30 mph at times, mainly Monday afternoon into early Mon evening. The flow will also become favorable for a brief period of lake effect snow into portions of the Finger Lakes Monday evening/night. With 850mb temperatures around -9 to -10 deg C and steady N/NW flow off of Ontario, there will be a threat of an inch or less of lake effect snow...mainly given the short duration (less than 12 hours)...and the shallow nature of the mixed layer (around 7 kft or less).

KEY MESSAGE 4...

The pattern later this week is expected to become more active after a brief mid-week break. There is still quite a bit of uncertainty regarding the timing, intensity and placement of the short waves that could rotate through the Northeast US Thursday and Friday. Deep moisture looks to be mostly lacking with these waves and the pattern remains mostly muted and not amplified, which will keep temperatures near normal and the environment mostly stable. There does appear to be another push of cold Canadian air from the northwest going into Saturday with temperatures back below normal.

AVIATION /18Z SUNDAY THROUGH FRIDAY/

Rain showers are moving through the area this afternoon allowing ceilings and visibilities to fall. MVFR to IFR conditions are expected all all terminals through the evening. There is a slight chance for thunderstorms at AVP from 20-23Z. Rain will gradually come to an end tonight though as it does, it may transition to light snow or freezing drizzle for ITH, SYR, and RME as cold air fills in. While there will also be some improvement to ceilings tonight, AVP, SYR, and RME will be the terminals that have the best chance for Fuel Alt/MVFR by the end of the TAF period.

Northwesterly winds follow the cold front with sustained speeds of 5 to 10 kts.

Outlook:

Monday through Tuesday...High pressure building in across the Northeast with mainly VFR conditions; Possible restrictions with morning fog.

Wednesday...Cold front begins to move in from the north with rain and snow showers as well as potential restrictions.

Thursday... Warm front pushes up from the southwest with rainshowers and restrictions possible.

Friday...Some lingering showers and restrictions possible before high pressure builds in Saturday.

BGM WATCHES/WARNINGS/ADVISORIES

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