textproduct: Binghamton

WHAT HAS CHANGED

The coverage of low chance PoPs was increased on Saturday, mainly for the afternoon and early evening as there will likely be scattered to numerous pop up instability showers, especially across Central NY. The trend of increasing winds and lowering dew points on Sunday was continued.

KEY MESSAGES

1) High pressure briefly builds with clearing skies and light winds allowing frost to develop across the area early this morning.

2) A cool air mass will remain across the region through the weekend with scattered rain showers expected this afternoon through Saturday. Snow may mix in across the higher elevations later tonight. Overnight low temperatures will fall into the low to mid 30s through Saturday night, allowing for continued frost/freeze chances in our growing zones into early Sunday.

3) Temperatures will be on the rise early next week. Despite the warmer weather, there will be multiple opportunities for showers through at least midweek.

DISCUSSION

KEY MESSAGE 1...

High pressure briefly builds in across the area early this morning and drier air moves in, especially at the mid-levels. The lower levels remain rather moist, so continue to be a few patchy clouds around and there can be some patches of valley fog as well prior to daybreak. The Frost Advisory remains in place until 9AM across the Finger Lakes region and Wyoming Valley where the growing season has officially begun as of today, with light to calm winds, especially across the lower elevations and lows fall back mainly in the lower to mid 30s. While some patches of frost are expected outside of the advisory area, the growing season begins May 11th for the rest of the CWA, thus no other areas will see any headlines early today or through the chilly spell of weather expected through the weekend.

KEY MESSAGE 2...

A broad upper level trough stretching from the northern Plains to the Northeast with a closed upper upper low drifting slowly from north of the Great Lakes to south of Hudson Bay will be the main feature through Sunday. A shortwave embedded in the flow and developing surface low will bring another round of showers this afternoon continuing into tonight. Temperatures at 850mb fall to around -3C to -4C late tonight into early Saturday morning (although the GFS is a little quicker and more aggressive pushing in the colder air faster and farther south). Where showers linger into the overnight, primarily east of I-81, there can be some wet snow that mixes in across the higher terrain before tapering off prior to daybreak Saturday. Lows will be in the 30s area-wide tonight.

With west to northwesterly flow continuing with cold air aloft, additional instability showers are expected Saturday, especially during the afternoon and evening. Highs will mainly be in the upper 40s to the mid 50s. The broad upper trough will become deeper and more amplified Saturday night into Sunday allowing for the cold, Canadian air to dip even farther south before the flow aloft becomes more southwesterly later Sunday night into Monday. As a result, Saturday night is expected to be the coldest night coming up with some clearing late and light winds, allowing lows to fall into the upper 20s to mid 30s. Additional frost/freeze headlines look likely at this time.

KEY MESSAGE 3...

Temperatures trend closer to average on Monday with the return of southwesterly flow and a more zonal pattern aloft. Highs Monday range from the upper 50s to the mid 60s with a low chance of showers as a warm front lifts through. A deepening upper trough over the Upper Midwest Tuesday will lead to stronger warm air advection ahead of the associated cold front, sending high temperatures into the upper 60s and lower 70s. Overnight lows Monday and Tuesday nights return to the 40s and 50s.

Showers and embedded thunderstorms along and ahead of the cold front are expected starting Tuesday and continuing into Wednesday as the front slowly pushes east.

AVIATION /12Z FRIDAY THROUGH TUESDAY/

Mainly VFR conditions are expected until the late afternoon. A batch of rain will move into the area after 21Z today, which will bring MVFR to Fuel Alternate restrictions to all terminals during the evening. Lingering low level moisture following these showers will result in a further deterioration of ceilings and potentially visbys late this evening/early Saturday morning. IFR restrictions are possible at the Central NY terminals tonight.

Outlook:

Saturday through Monday... Mainly VFR, but restrictions will be possible at times in isolated to scattered showers.

Tuesday...Scattered showers and associated restrictions possible.

BGM WATCHES/WARNINGS/ADVISORIES

PA...Frost Advisory until 9 AM EDT this morning for PAZ044-047. NY...Frost Advisory until 9 AM EDT this morning for NYZ015>018.