Marine Weather and Tide Forecast for Chester, VT

NEAR TERM /THROUGH TONIGHT/
Despite an upper level low, east of Maine, departing farther out into the Atlantic, we will remain under the influence of moist, cyclonic flow and an upper level trough pattern today.
925-850 hPa RH values remain high through this afternoon (80 to 95 percent) which will likely result in continued mostly cloudy conditions. 850 hPa temperatures similar to Monday (+1 to +4C)
will keep high temperatures around 10 degrees below normal, only in the 50s to mid-60s. Similar to Monday, portions of the Adirondacks and southern Greens may not get out of the 40s.
Onshore flow from the Atlantic could result in a few light rain showers or sprinkles across portions of western New England during the afternoon hours; otherwise, all areas will remain dry once again. The pressure gradient will relax slightly as the upper low departs, so it will not be as breezy as Monday, but some gusts of 20 to 25 mph could still occur.

Generally cloudy conditions will continue tonight as easterly onshore flow increases. In addition, clouds associated with a low pressure system approaching from the Ohio Valley will also increase. Most areas will remain dry but some onshore light rain showers or sprinkles are possible in some spots. Rain associated with the approaching system will near southern areas toward daybreak but much of this will hold off until the daytime hours Wednesday. Lows fall back into the 40s for most with some upper 30s across the Adirondacks and southern Greens.

SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/
A complex double-barrel low pressure system will bring a widespread rainfall to the region during the short term period.
An initial upper level shortwave and surface low pressure system will trek across the Ohio Valley on Wednesday. Increasing moisture advection and forcing for ascent will result in periods of rain overspreading the region from south to north throughout the day. The northward advancement of precipitation may be slow as it will encounter increasing mid-level dry air from a high pressure system to the north and east across Atlantic Canada. By Wednesday night, an upper level low attempts to develop near the lower Great Lakes as the shortwave undergoes a negative tilt as it nears the mid- Atlantic coast. Continued upper level forcing for ascent and increasing divergent flow will maintain periods of rain through Wednesday night. As dynamic wet-bulb processes take shape, some of the highest peaks of the Adirondacks and southern Greens (especially above 3000 feet)
could see some snowflakes mix in but no accumulation is expected. Highs Wednesday will be mainly in the 50s to near 60 with lows Wednesday night falling back into the mid-30s to mid-40s.

On Thursday, the upper level shortwave continues to increase its negative tilt near the Atlantic coast and results in the gradual development of a coastal low (developing similar characteristics to that of a wintertime/early spring nor'easter) which will then track northeastward off the coast.
Over time, this coastal low will become the primary, stronger low as the inland low near the lower Great Lakes weakens.
Periods of rain will continue on Thursday with the steadiest rainfall developing mainly near or east of the Hudson Valley by Thursday night once the coastal low takes over. How much rain occurs during this period remains a bit uncertain but a general 0.50 to 1.00 inches of rain is expected with the higher amounts across southern areas. The long duration and non-convective nature of this event should limit hydrological concerns. The clouds and rain will lead to a chilly day on Thursday with highs only in the 40s to lower 50s. Daily record low maximum temperatures will be challenged at Albany, Glens Falls and Poughkeepsie. Lows once again fall back into the upper 30s to mid-40s Thursday night.

LONG TERM /FRIDAY THROUGH MONDAY/
Cloudy and unseasonably cool weather continues for the first half of the upcoming Memorial Day weekend as our occluded coastal low from Thursday exits into the Canadian Maritime and its upper level low becomes absorbed by the parent trough slowly rotating eastward out of the Great Lakes. With the broad parent trough and its associated cold pool persisting overhead Friday into Saturday with deformation processes also at play on Friday, each day will feature diurnally driven isolated to scattered showers. The highest probability for showers (50 - 60% chance)
remain over the southern Adirondacks, northern/eastern Catskills, Taconics, and southern Greens due to upslope flow enhancements. Despite chance to even likely POPs in the forecast, probabilistic guidance continues to support overall low QPF amounts with mainly 25% or less for rainfall amounts to exceed 0.10" each day. Given the isolated to scattered shower character, we used coverage wording (isolated/scattered/numerous) instead of probabilistic (slight chance/chance/likely) to describe the shower potential both days. We hope this helps communicate that we are not expecting washouts and that there will likely be periods of dry time.
Otherwise, unseasonably cool temperatures persist under cloudy skies with daytime highs 10 to 15 degrees below normal for late May standards. Cloudy skies at night will limit the diurnal temperature change overnight and thus prevent frost.

While some gradual improvements are expected for the second half of the holiday weekend, latest ensemble cluster guidance continues to suggest that broad troughing continues or, at best, zonal flow develops Sun - Mon. Monday features higher potential for more dry time. Should troughing continue with limited sun, temperatures will likely remain cooler than normal. However, if we finally see breaks of that strong May sun, tempertures will likely rise closer to normal (upper 60s to low 70s). Still moderate uncertainty on the cloud coverage at this lead time but probabilistic guidance favors a warming trend with temperatures inching closer to normal as we close the weekend. We also limited POPs to just slight chance and chance (highest POPs in the higher terrain areas) given uncertainty on the exact timing and placement of shortwaves within the potential broad troughing pattern.

AVIATION /08Z TUESDAY THROUGH SATURDAY/
Through 06z Wednesday...Low end VFR conditions persist at ALB/POU/GFL through 00 - 03 UTC while MVFR cigs continue at PSF as our upper level low continues to slowly exit into the Canadian Maritime. The wind direction becomes more northerly and eventually northeasterly towards the end of the TAF period resulting in more of an onshore flow and advecting marine moisture inland. This will result in MVFR cigs returning to POU with potentially near IFR cigs ensuing at PSF. Some patchy mist cannot be ruled out as well at PSF but not enough confidence to include at this time. Northwest to northerly flow around 5-10 kts with gusts near 15 kts through sunrise become breezy once again by 14-16 UTC with sustained winds reaching 8-12 kts and gusts up to 20kts. Winds continue shifting north to northeasterly late this afternoon into this evening but trend weaker, sustained 5-8kts.

Outlook...

Wednesday Night: High Operational Impact. Pds RA.
Thursday: High Operational Impact. Pds RA.
Thursday Night: High Operational Impact
Likely SHRA
RA.
Friday: Moderate Operational Impact. Scattered SHRA.
Friday Night: Moderate Operational Impact. Numerous SHRA.
Saturday: Moderate Operational Impact. Scattered SHRA.
Saturday Night: Low Operational Impact. Isolated SHRA.
Sunday: Low Operational Impact. Isolated SHRA.

CLIMATE
Record low maximum temperatures for May 22:

Albany: 52F (2005)
Glens Falls: 52F (2005)
Poughkeepsie: 56F (2005, 2003)

ALY WATCHES/WARNINGS/ADVISORIES
CT...None.
NY...None.
MA...None.
VT...None.