textproduct: Binghamton

WHAT HAS CHANGED

Another risk of severe thunderstorms is anticipated this afternoon through early evening, though confidence has increased that the threat will be primarily north of the Twin Tiers.

KEY MESSAGES

1) Scattered thunderstorms are again expected this coming afternoon into evening, though this time especially north of the Twin Tiers. Strong wind gusts and locally heavy rain are the primary threats.

2) A dramatic pattern shift will occur over the weekend with a a round of rain and perhaps thunder Saturday evening followed by much colder weather early next week including snow showers for some parts of the area.

DISCUSSION

KEY MESSAGE 1... For the third consecutive day we will have a risk for severe thunderstorms, though this time the focus will be especially north of the Twin Tiers.

A subtle shallow boundary left behind by the convection we just had in the evening, will drift right back north during the day to allow well above normal temperatures to be realized again with highs in the mid 70s to mid 80s. Dewpoints will be into the lower 60s at most locations, so it will definitely feel ahead of pace compared to the calendar.

Unlike the prior couple of days, there will be more forcing via an incoming upper wave and eventual frontal passage. Modest height falls will occur aloft, as southwesterly warm air advection occurs below. A rather robust and even top-heavy Convective Available Potential Energy profile should set up for the Finger Lakes to Central New York pointing to not just damaging gusts but also potential for large hail; farther south there will be more uncertainty because of convective inhibition/thermal capping holding on even late in the day.

The SPC Convective Outlook continues to highlight a good portion of Central NY in the Slight Risk for severe storms. Convective initiation looks to be between 3-5 PM across the Finger Lakes or just to the north. These storms will push eastward quickly, initially in discrete mode, but then potentially becoming more linear with time. As mentioned the primary threats are likely hail and damaging winds. An isolated tornado cannot be totally ruled out within storm-scale boundary interactions, and the Mohawk Valley sometimes can cause its own topographical influences. However, shear even for Central New York will be mainly unidirectional since the boundary will lift so far north this afternoon.

It was a good thing that most rainfall during the event that just concluded was mostly in the central to southern part of the area, because the northern third remains sensitive. That said, for the coming afternoon-evening, we will still have to keep an eye on potential for isolated localized flooding where it is the most sensitive. Speed of cells though will probably mostly mitigate the threat, and thus is more of a secondary risk.

KEY MESSAGE 2... Above normal temperatures continue up to Saturday, but a rainy cold front in the evening will herald an abrupt pattern flip to much cooler weather for Sunday into Monday.

Temperatures will bump down some on Friday in the wake of the prior batch of thunderstorms, yet still above normal with highs of mid 60s to mid 70s. There could still be a few lingering showers early Friday, otherwise passing high pressure will provide for window of dry weather through at least midday Saturday.

An upper trough will dig into the Western Great Lakes Saturday, with deep southwest flow boosting temperatures well into the 70s across the area. This will occur ahead of a very well-marked front trailing from strong Canadian low pressure. A narrow yet significant ribbon of moisture will pool all the way up from the Western Gulf, causing rain and embedded thunder to sweep across our region late Saturday through Saturday night.

Abruptly colder weather will be ushered in during the second half of the weekend. Temperatures Sunday will initially range from the mid 40s to lower 50s, yet under strong cold air advection with gusty winds and scattered showers. Temperatures plummet into the mid 20s to near 30 Sunday night, with any lingering rain showers changing to snow showers/flurries. Highs on Monday will only reach into the upper 30s and lower 40s, and a few lake enhanced snow showers cannot be ruled out anywhere across central NY and northeast PA. Drier air settles in Monday night which will be our coldest; 20s areawide. Temperatures recover back into the 50s and 60s going into the middle of next week.

AVIATION /06Z THURSDAY THROUGH MONDAY/

Now that the storms and rain have moved out of the area, lingering low ceilings and patchy fog/mist will be observed at the majority of terminals, but expected to stay VFR, with exception to RME and SYR. Low clouds through 12z from a weak quasi-stationary boundary could drop restrictions to MVFR. Confidence is moderate, but was included in the 06Z TAF package. Otherwise, expect VFR conditions areawide through Thursday afternoon, before showers and storms are expected in the evening hours.

Outlook:

Thursday evening through Friday...Restrictions possible from scattered showers and thunderstorms.

Saturday...Occasional restrictions possible in scattered showers and thunderstorms late in the day. Otherwise, mainly VFR.

Sunday...Restrictions possible from rain showers.

Sunday night through Monday...Occasional restrictions possible in scattered rain and snow showers.

BGM WATCHES/WARNINGS/ADVISORIES

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