textproduct: Binghamton

WHAT HAS CHANGED

No significant changes have been made with this forecast update.

KEY MESSAGES

1) A strengthening ridge of high pressure will be our main feature early this week leading to above average temperatures and increasing humidity through Tuesday. A few isolated afternoon showers and thunderstorms are possible both Monday and Tuesday.

2) A cold front will bring the potential for stronger thunderstorms Wednesday afternoon, then cooler conditions return for the second half of the week.

DISCUSSION

KEY MESSAGE 1...

A frontal boundary currently north of Lakes Erie and Ontario and across far northern NY is expected to dip a bit farther south this evening across north-central NY before retreating back northward as a warm front later tonight into early tomorrow. This front can lead to a couple of isolated showers, especially late tonight north of the NYS Thruway.

As the front retreats, southwesterly flow develops tonight through Tuesday as surface high pressure becomes anchored around Bermuda and an upper level ridge centered off the Southeast Coast strengthens and builds northward leading to strong warm air advection and increasing dew points. All this put together will give us a taste of summer-like conditions, through Tuesday. Highs tomorrow and Tuesday are expected to be in the mid 80s to lower 90s area-wide and can be record-challenging. The record high for both days at KBGM is 87, KAVP's record highs are 93 tomorrow and 92 Tuesday, and for KSYR the record highs are 90 and 92 respectively. NBM guidance continues to look too warm compared to nearly all model guidance due to a known seasonal bias, so the trend to lower temperatures a bit from the model blend was continued, but highs were kept near or just above the warmest guidance given the favorable synoptic set up for temperatures to overachieve. However, confidence in those temperatures is a bit mixed. There is the potential for some scattered clouds and isolated showers or thunderstorms to pop up during the afternoon and early evening hours tomorrow and Tuesday as a couple of weak waves embedded in the flow around the ridge move through, which could result in high temperatures being held back slightly. If little in the way of convection develops, temperatures could potentially overachieve, and that could be the case especially tomorrow as some model soundings do show a cap in place.

As mentioned, dew points will be on the rise, reaching the low to mid 60s tomorrow and Tuesday, with some spots even reaching the upper 60s Tuesday afternoon, so the humidity will be noticeable. Some guidance continues to be more aggressive with the increase dew points, especially tomorrow night into Tuesday, so this is something to keep an eye on.

KEY MESSAGE 2...

The next opportunity for widespread showers and thunderstorms will be with a cold front moving into the region on Wednesday. As of now, the bulk of the convection looks to be from midday through the afternoon, and while there remains some uncertainty with regards to the exact timing, the best instability seems to be setting up across NE PA through portions of the Southern Tier of NY and into the southern Catskills. This coincides with the warmest temperatures Wednesday where highs are expected to range from the mid 70s to the mid 80s, while noticeably cooler air returns to the Finger Lakes region through the Tug Hill with highs in the upper 60s and lower 70s. If everything can come together, some locally strong to severe thunderstorms can't be ruled out for the afternoon and early evening, especially across NE PA and the southern Catskills. So far deterministic and ensemble guidance shows a general 500 to 1000 J/kg of CAPE (with higher values from the NAM), about 30 to 40 knots of shear and decent low-level lapse rates in this area. High temperatures are expected to fall back into the 60s in the wake of the front for the second half of the week.

AVIATION /21Z SUNDAY THROUGH FRIDAY/

VFR conditions expected through the period. There is a small chance that ELM/ITH/SYR/RME could see brief MVFR - IFR fog during the predawn hours, but probability of occurrence is low at this point, so it was left out of the forecast. From around 03-06z, skies will be mostly clear and winds in the lower atmosphere will be mostly calm as high pressure will be over the area. With dewpoints in the upper 50s, if the temperature can drop quickly enough, then some brief patchy fog could occur, but as mentioned, this probability is low and will pick up in the lower atmosphere through the early morning hours, mixing out any saturation that may occur at the surface.

Outlook:

Monday night...Mainly VFR; slight chance for afternoon isolated showers/thunderstorms with brief MVFR/IFR restriction possible.

Tuesday...Mainly VFR, but afternoon scattered showers and thunderstorms may result in brief restrictions.

Wednesday...Scattered showers and thunderstorms and associated restrictions possible as a frontal boundary moves into the area.

Thursday and Friday...Mainly VFR.

BGM WATCHES/WARNINGS/ADVISORIES

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