textproduct: Binghamton

WHAT HAS CHANGED

Little change to previous forecast.

KEY MESSAGES

1) Warm and dry through tomorrow afternoon ahead of a front that moves in towards the evening bringing showers and thunderstorms, some of which could contain gusty winds.

2) Generally dry benign weather returns towards the end of this week, with temperatures bumping back up over the weekend.

DISCUSSION

KEY MESSAGE 1...

Upper level ridging is building in today ahead of an approaching trough moving along the US/Canada border. Temperatures tonight into tomorrow will be a little above average with dew points gradually rising as precipitable water values rise to near 2 inches tomorrow afternoon into the overnight hours. An area of low pressure moving through Southern Canada will swing a cold front into the region in the evening to early overnight hours.

Ahead of this front, wind shear increases with bulk shear around 50 knots. The uncertainty will be CAPE as post sunset, the boundary layer will stabilize quickly. Confidence has increased that the western Finger Lakes may see the front arrive towards sunset where there could still be some surface instability for stronger winds to mix down. SPC has highlighted this area with a slight risk of severe thunderstorms. Dry air advecting in behind the thunderstorms could help with downdraft production from the dry air entrainment into the core of the storms. If the downdrafts can be strong enough, the could punch into the stable boundary layer even a few hours after sunset so SPC's marginal risk has been extended into CNY and parts of the Twin Tiers. Confidence is low that the severe risk will make it much east of the Finger Lakes though given that Most Unstable CAPE quickly falls below 500 even in some of the more aggressive models. Thunderstorms may continue thanks to forced lift along the front but their ability to produce damaging winds at the surface will diminish quickly after dark.

Flash flood risk is also lower in this event despite the 2 inch PWATs as the front is pretty progressive and the shear vectors dont line up well for persistent training. Rainfall rates will still be high with any thunderstorm so localized urban flooding is possible if thunderstorms move through a larger urban area.

KEY MESSAGE 2...

The front is likely east of the region by Thursday morning with drier NW flow. With the front sweeping most moisture well off to the southeast and the NW flow continuing through the weekend, cooler and dry weather is expected through this weekend. Zonal flow aloft will prevent any significant cool downs or warm ups and with the lack of moisture in place, any shortwaves moving through will just cloud things up briefly rather than produce much precipitation. Sunday into Sunday night has the best chance at some isolated to scattered rain showers as models are hinting at a stronger shortwave and cold front moving in.

AVIATION /18Z TUESDAY THROUGH SUNDAY/

VFR conditions are expected through the entire TAF period as high pressure dominates. Fog tonight looks less likely as more clouds are expected to stream overhead. Light and variable winds are also expected this evening and overnight, with southwest winds developing tomorrow.

Outlook...

Wednesday through Thursday...Potential cold front passage with wind shift and showers. Highest chance for showers later Wednesday through Thursday morning.

Friday through Saturday...Mainly VFR with high pressure building into the region. Morning fog will be possible.

Sunday...Restriction possible as frontal system approaches the region.

BGM WATCHES/WARNINGS/ADVISORIES

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