Radar — KCXX
Surface Analysis — Eastern U.S. (North)
Satellite
Nearest monitored road: Main Street (Primary)
As of 222 PM EDT tuesday...
A flood watch has been issued for much of central/southern vermont and essex county ny. Expected rainfall in those areas has increased. Amounts between 2-3 inches should fall in most places, with isolated amounts up to 5 inches possible. Isolated to scattered flash flooding is possible there.
As of 222 PM EDT tuesday...
1. Periods of rain continue tonight through wednesday night. Localized flash flooding is possible if storms repeatedly track over the same area.
2. After a brief period of drier weather, unsettled conditions are expected to return later this weekend into the beginning of next week.
As of 222 PM EDT tuesday...
Key message 1: an upper-level low builds into the region today and remains over the area into thursday. An associated surface low has formed over the great lakes and it will occlude as it moves into new york and new england, bringing consistent showers. The widespread showers have entered northern new york, and scattered showers and thunderstorms have developed across the higher terrain in vermont. As the afternoon and evening progress, the combination of strengthening synoptic dynamics and increasing instability will cause these showers to become widespread. A lack of deep-layer is expected to prevent any severe threat though. These storms will likely have the highest rainfall rates of the entire event, but dry antecedent conditions and some south to north storm motion should keep the flood threat relatively low through this afternoon. The axis of rain will become more SSE-NNW oriented heading into this evening and night, and mostly stall in the same locations. However, as the evening goes on, this axis of rain looks to become a more broken line, so there will be rounds of showers heading over the areas but likely not constant rain. While the precipitation should trend toward more stratiform as the night goes on, some convective enhancement will still be likely, especially in southern vermont where the highest totals are expected. This tuesday night into wednesday morning would likely have the highest concern for any flash flooding as the axis of rain looks to stay relatively stationary. Heading through tomorrow, the dynamics weaken and the axis of rain looks to become more broken and lighter. Periods of showers will continue tomorrow night through thursday, but they will become much lighter and gradually less widespread as the surface low weakens and pushes east. The area of highest concern is the eastern slopes and spine of the southern green mountains where the best dynamics will combine with upsloping. The east slopes of the adirondacks will likely be the second area of focus due to the upsloping. Most areas will see between 1-3 inches of rain, but isolated areas up to 5 inches are possible in parts of the southern greens. Still, in the more favored areas, only isolated to scattered flash flooding looks to be possible. The champlain valley and northeast kingdom will likely receive some locally lower totals due to downsloping. Showers will become much more isolated heading into friday.
Key message 2: brief ridging across the region will continue to bring drier conditions for the start of the weekend. Seasonably warm temperatures are expected for the start of this weekend, with high temperatures in 80S areawide. Unsettled weather conditions are expected to return for the latter half of the weekend into the beginning of next week as another shortwave trough moves through, although there is still some uncertainty regarding the timing of this feature and how widespread showers will be. Temperatures will largely be influenced by any cloud cover and precipitation, but above normal temperatures are anticipated with highs climbing into the mid 70S and 80S with overnight lows in the upper 50S and 60S.
Through 00Z thursday...rain and a few rumbles of thunder are lifting north across the region. A few downpours have dropped visibilities below 3sm, but the extent of heavy rain has been diminishing. Upcoming activity is not expected to have much lightning, and no explicit mention of thunder is noted for any taf, but could occur through 06Z and again after 13Z wednesday. Favored a gradual reduction in ceilings and visibility with the potential for the worst surface conditions around 09Z-17Z with most terminals IFR or near-IFR. This will be timed with heavy rain associated with a surface low expected to pass north. Winds will go calm or variable on its approach. Southeast winds will then be favored across vermont, and northeast over northern new york with speeds increasing to 6-11 knots sustained, with some downslope gusting at areas like krut up to 20-22 knots. Eventually, low pressure will develop more strongly off the new england coast. Surface winds will begin to diminish, but the flow aloft will remain southeasterly at 30-40 knots at 2000 ft agl across vermont. Some llws is noted. As the surface low decays, conditions are expected to improve. However, across vermont, there will likely be some redeveloping convection 18Z wed to about 03Z thurs, which could produce locally heavy rain reducing visibilities.
Outlook...
Wednesday night: mainly VFR, with local IFR possible. Chance shra. Thursday: mainly MVFR, with local IFR possible. Chance shra, slight chance tsra. Thursday night: mainly VFR, with local MVFR possible. No sig wx. Friday: VFR. Slight chance shra. Friday night: VFR. No sig wx. Saturday: VFR. No sig wx. Saturday night: VFR. Slight chance shra. Sunday: VFR. Chance shra, chance tsra.