textproduct: Binghamton

WHAT HAS CHANGED

No significant changes made to the forecast.

KEY MESSAGES

1) Scattered showers and thunderstorms are expected again today with a few producing heavy rain and damaging winds.

2) Quiet weather is anticipated Sunday before the pattern becomes active again Monday through the middle of the week.

DISCUSSION

KEY MESSAGE 1...

Broad cyclonic synoptic flow in place across the Northeast US today helping to keep the active weather in place. A pre-frontal trough is rotating through central NY/PA this morning and combining with a modest amount of deep moisture (PWs around 1.5 inches) to produce mainly rain showers, but also an area of thunderstorms tracking east over the northern Finger Lakes. There is a sufficient amount of instability (ML CAPE values around 500-1000 J/kg) for this line of convection to tap into, but the limited forcing from the short wave and minimal amount of deep layer shear is keeping the convection on the weaker side.

As this line of convection tracks east and the morning continues to heat up, the boundary layer will destabilize further and allow for additional convective initiation and deeper, potentially more organized storm structure. SPC has expanded the Marginal Risk for severe storms farther north and also place parts of Pike County PA and Sullivan County NY in the Slight Risk category.

The primary concern will be for heavy rain and training convection that could potentially produce flash flooding, especially in locations that have seen significant rain the past several days. Pockets of PWs above 1.5 inches, warm cloud depth above 10kft, short MBE vectors and the potential for storms to move parallel to boundary dragging across the region will all contribute to the threat for isolated areas of heavy rain/training storms and flash flooding.

There is also a concern for damaging winds from downbursts in any of these storms that generate enough vertical depth, or become organized due to localized storm-induced shear profiles.

Most of the convection will be focused along this pre-frontal trough as the primary cold front hangs back well to the west and does not move through until later this evening/tonight. The bulk of the strong to severe storms will likely impact the region before 5-7 PM this evening, with lingering rain showers and possible a few weak storms after 7 PM and nearly all precipitation done after 1 AM.

KEY MESSAGE 2...

Weak high pressure builds in from the west tonight, which will allow for some clearing to occur along with winds diminishing...leading to enough raditional cooling to generate patch fog. After the fog mixes out on Sunday morning, the rest of the day should remain dry and quiet.

The early part of Monday should be mostly quiet as well, but the next round of showers and storms looks to move in from the west later in the day Monday. There is some indication that the remnants of a Midwest MCS could be tracking east through the southern Great Lakes Sunday night/Monday morning and eventually into NY/PA by Monday afternoon. An embedded upper short wave along with this convective system may help sustain the storms as they track to the east. This will require close watching as there could be remnants of an EML associated with this convection as well.

Chances for showers and storms Tuesday and Wednesday appear to be on the lower side, but given the warm temperatures and high surface dew points, persistent cyclonic flow and sporadic weak short waves within the flow, any one period cannot be ruled out completely for thunderstorms.

A higher chance for showers and storms arrives Thursday with the arrival of a deep upper trough and associated stronger forcing. The weekend may be cooler and drier if this trough can kick east in time.

AVIATION /18Z SATURDAY THROUGH THURSDAY/

Scattered showers and isolated thunderstorms will persist through this afternoon and into the evening with an overall shift eastward later in the day. If a thunderstorm moves over a terminal today, visibility will be reduced to less than 1 mile with ceilings below 2000 ft. There is also the threat of heavy rain and wind gusts +40 kt with these storms.

Conditions subside after 8 PM this evening with some clearing and the potential for fog formation late, especially at ELM and BGM. Southwest winds around 10 kt today will become less than 5 kt tonight and then shift to the west/nw Sunday after 13Z with gusts up to 15 kt after 16Z.

Outlook:

Sunday through Monday morning...Mainly dry with VFR conditions expected.

Monday afternoon through Thursday...Unsettled pattern with periods of showers and scattered thunderstorms with associated restrictions. Restrictions with overnight fog/low clouds are also possible.

BGM WATCHES/WARNINGS/ADVISORIES

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