textproduct: Binghamton

WHAT HAS CHANGED

Minor adjustments to PoPs, QPF and thunderstorm chances this afternoon and evening. PoPs, QPF and thunderstorm chances were increased and expanded northwestward on Saturday; brining isolated t'storm chances across the Twin Tiers, Catskills and NE PA. Tuesday is trending hotter, with higher heights, thicknesses and temperatures aloft in the latest guidance.

KEY MESSAGES

1) Scattered showers and thunderstorms are expected across the Central Southern Tier and Northeast PA into the evening hours; a few storms could be strong with gusty winds and heavy rain.

2) Scattered showers and isolated thunderstorms will again be possible on Saturday as a slow moving front drops south. However, much of the day will be mostly sunny and seasonably warm.

3) A large upper level ridge of high pressure brings dry and hot weather to the area early to mid week. A front likely brings temperatures back down closer to normal by the end of the upcoming workweek.

DISCUSSION

KEY MESSAGE 1...

Showers and thunderstorms are developing south of a weak wind shift frontal boundary this afternoon. The main area for these showers and storms heading into the evening hours looks to be south of a line from about Hornell--Elmira--Binghamton and Monticello. Temperatures are rising into the upper 70s and lower 80s, along with surface dew points in the 60s. This is creating MLCAPE between 750-1500 J/kg in the above mentioned area. PWATs are between 1.5 to 1.8 inches in this area as well, with deep layer shear running 25-30 kts. Overall, this setup will potentially yield a few stronger storms and some heavy rain producers. Some of the stronger storms could produce wind gusts of 30-40 mph, or isolated higher gusts. Rainfall rates around 1"/hr will be possible as these storms slowly move off to the south and east...can't rule out isolated higher rain rates. Flash flood guidance is 1.5-2"/hr across the Southern Tier and Northeast PA, so we will be monitoring rainfall amounts and rates closely into this evening. There remain a marginal risk for severe storms and excessive rainfall across the Central Southern Tier of NY and most of NE PA. The showers and storms should taper off and end shortly after sunset. Overnight will be mostly clear with patchy fog developing, lows dip into the upper 50s and 60s.

KEY MESSAGE 2...

The weak frontal boundary, characterized by a moisture gradient and subtle wind shift will be positioned along I-80 in NE PA by Saturday morning. Instability will build across the entire area through the day, with between 600-1200 J/Kg of MLCAPE expected. The latest CAMs such as the HRRR, 3km NAM and 12z RRFS are showing isolated showers and storms popping up over the higher terrain of east-central NY and dropping south across NE PA heading into the late afternoon and early evening hours. Therefore, with these latest indications from the CAMs, increased PoPs above the latest NBM, to include generally a mention of isolated thunderstorms in the forecast. Otherwise, Saturday will be mostly sunny and warm with highs in the upper 70s to mid-80s across the region.

KEY MESSAGE 3...

Sunday and Monday are looking dry, mostly sunny and warm with a surface high pressure in place. Then, the building heat dome over the upper Midwest and Central Great Lakes shift east for Tuesday. 500mb heights rise to around 594dm, with 1000-500mb thicknesses up around 580dm expected. 850mb temperatures surge to around +21C. Skies will be sunny under the upper level ridge and dew points look to mix out into the low/mid-60s for the afternoon. This should allow daytime highs to surge up into the upper 80s to mid-90s. This will be close to daily record highs, and be about 10-15 degrees above average for mid-July. The core of the truly extreme heat looks to remain just west of our area. A trough and NW flow develops by Wednesday, with 850mb temperatures sliding back sliding back to around +18C and around +15 by Thursday. This will bring high temperatures back down into the 80s for most locations. The weather looks to remain dry Tuesday through Thursday.

AVIATION /00Z SATURDAY THROUGH WEDNESDAY/

Mainly VFR throughout the period. Potential for fog or stratus formation overnight at KELM for a few hours. A stray shower or thunderstorm can not be ruled out Saturday. Coverage and confidence too low for TAF inclusion at this time.

Outlook:

Saturday night into Tuesday...Mainly VFR, with possible morning fog at KELM.

Wednesday... Mainly VFR.

BGM WATCHES/WARNINGS/ADVISORIES

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