Marine Weather and Tide Forecast for Cheshire, MA

NEAR TERM /THROUGH TONIGHT/
Key Messages:

- The Storm Prediction Center continues a slight risk (level 2 of 5) for severe thunderstorms mainly north and west of the Capital District this afternoon into this evening with damaging winds (15-29% chance) the primary hazard.

Discussion: As of 645 AM EDT...An upper level ridge axis is centered right over the area, as ridging extends northeast from the Gulf Coast across the Appalachians and mid Atlantic and towards New England. Surface high pressure is located just southeast of the area off the coast of the mid Atlantic States. Through the morning hours, the ridge axis will continue to shift eastward, as an upper level shortwave over the Upper Midwest heads towards the Great Lakes. The surface high pressure area will continue to slowly shift east-southeast as well. Meanwhile, a strong surface cold front associated with the upper level disturbance will be marching across the Great Lakes region and is expected to get close to western New York towards sunset.

IR satellite imagery shows fairly clear skies over the region early this morning, although some thin cirrus clouds are in place. Skies will be mostly clear for the start of the day, with just some passing high clouds for this morning. Temps have been variable early this morning, although sheltered areas have fallen into the 30s, while the rest of the area remains int he mid 40s to lower 50s.

With plenty of sun expected this morning and a mild southerly flow in place, temps will quickly rise through the morning hours. Based on model soundings and blended guidance, highs should reach the mid 70s to low 80s for most areas this afternoon. The warmest temps may be right in the Capital Region, where some hires guidance shows compressional warming may lead to localized temps in the lower to perhaps mid 80s by late this afternoon. The increasing pressure gradient will allow for breezy conditions this afternoon, with southerly winds gusting up to 30 mph at times, especially within the Hudson Valley, where winds will be locally channeled. The southerly flow will help increase the low-level moisture as well. Although the day will start off with dewpoints into the 30s, they will steadily rise into the middle 50s by later this afternoon.

With the limited low-level moisture in place and some mid level capping in place, SBCAPE will be somewhat limited for today.
Latest NBM shows values generally under 500 J/kg across the area through much of the day, with highest SBCAPE values over western and central New York. However, as the upper level trough starts approaching for late today, heights falls aloft will help erode this mid-level cap and lapse rates aloft be increasing.
Mid- level lapse rates may reach 6-7 deg C/km by late today and MUCAPE values may reach up to 1000 J/kg. Plenty of shear will be in place, with 0-6 km bulk shear in the 40-50 kt range. The convective mode will favor a broken QLCS or short lines to develop and spread west to east. These lines of convection will develop ahead of both the cold front and a pre- frontal trough over western/central NY and will be heading eastward towards our area from the 5pm-10pm time period. CAMs suggest that despite the limited instability, these lines could hold together until instability wanes enough, allowing for a severe threat for at least the western half of the area (mainly from the Capital Region on north and west). With the linear mode expected, damaging winds would be the main threat, as the limited instability probably won't allow for much hail today (although it cannot be ruled out in any stronger storms).

By the late evening, the loss of daytime heating will allow for lowering instability and any activity around will start to weaken. Some lingering showers are possible towards midnight, but the front should be finally crossing from west to east around that time. Behind the front, cooler and drier air will move in for the late night hours, with much colder temps expected by daybreak. Lows will range from the mid 30s in the Adirondacks to the mid 50s in Dutchess and Litchfield Counties, where the front will be crossing later in the overnight.

SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/
Drier and more comfortable weather is expected on Wednesday. Any morning clouds will be departing, allowing for a mostly sunny sky by afternoon. It will be somewhat breezy in the morning due to a lingering pressure gradient with winds gradually decreasing by later in the day. While high terrain areas will only top out in the 50s, it still should reach into the 60s for valley areas.

With high pressure overhead, chilly and quiet weather is expected for Wednesday night with a mostly clear sky. Some patchy frost may develop across parts of the Upper Hudson Valley, with the growing season beginning on Thursday morning.
Temps will range from the upper 20s in the Adirondacks to the lower 40s in the mid Hudson Valley.

It will remain dry for much of Thursday, although clouds will be increasing ahead of the next storm system. Highs will mainly be in the 60s. As a warm front approaches the area, some showers are expected on Thursday night, with the highest POPs for western and northern areas. Precipitation generally looks fairly light and temps will be in the upper 40s to lower 50s.

LONG TERM /FRIDAY THROUGH MONDAY/
Key Message:

- Showers likely Friday afternoon along with some thunderstorms.

Discussion:

A warm front lifts north of the region Friday morning placing our region within the warm sector of a low pressure system tracking northeastward into Quebec. Showers and thunderstorms will develop within the warm/humid air mass, aided by a passing upper level shortwave/prefrontal trough, during the afternoon and evening hours.
Highs Friday are expected to reach the 70s to near 80 with some upper 60s across the higher elevations. A deep upper level trough then approaches the region to start next weekend which may induce another developing surface low along the passing cold front which may track near or up the East Coast. Forcing for ascent could result in another period of rain for much of the area Saturday. Saturday would not be as warm with highs only in the 50s and 60s. High pressure attempts to nose in for Sunday and Monday bringing the return of drier weather with highs both days remaining in the 50s and 60s. The upper level pattern becomes more uncertain by early next week, however, with solutions varying from the upper trough from the weekend closing off and meandering nearby or fully departing out to sea with ridging building in.

AVIATION /12Z TUESDAY THROUGH SATURDAY/
Through 12z/Wed...VFR conditions will continue at all TAF sites through much of this afternoon with occasional high clouds and some developing cumulus later this afternoon. A band of showers and possible thunder will begin to cross the TAF sites starting around 23z/Tue to 00z/Wed. Maintained PROB30 groups with TSRA for KALB/KGFL and SHRA at KPSF/KPOU with this update. Flight category reductions are likely to occur within these showers and storms along with some brief, gusty winds. Start timing of precipitation may need to be adjusted in later TAF issuances. A few showers will linger until around 06z/Wed before the cold front passes ending precipitation for the rest of the overnight hours. Cigs are expected to lower to borderline MVFR/VFR levels with the higher confidence for MVFR cigs at KPSF.

Wind will increase out of the south at 10-20 kt this morning with some gusts 25 to 30 kt this afternoon, strongest at KALB. Wind will then become southwesterly at around 10 kt this evening when switch to the northwest behind the cold front (after 06z/Wed) at 10-20 kt with gusts 20-30 kt.

Outlook...

Wednesday Night: No Operational Impact. NO SIG WX.
Thursday: No Operational Impact. NO SIG WX.
Thursday Night: Moderate Operational Impact. Chance of SHRA.
Friday: High Operational Impact. Breezy
Likely SHRA
TSRA.
Friday Night: Moderate Operational Impact
Likely SHRA
TSRA.
Saturday: Moderate Operational Impact. Chance of RA.
Saturday Night: Moderate Operational Impact. Chance of SHRA.
Sunday: Low Operational Impact. Slight Chance of SHRA.

FIRE WEATHER
A southerly flow will be in place today ahead of an approaching cold front. RH values will be as low as 30 to 40 percent early this afternoon, although low level moisture will be increasing ahead of the boundary. Southerly winds may gust 20 to 30 mph at times today, especially within the larger north-south valleys.
Some showers and thunderstorms are possible late today into this evening, especially for areas north and west of the Capital Region, where rainfall amounts may exceed a third of an inch.
With the expected gusty winds and lower RH during a portion of the day, a Special Weather Statement is in effect for Berkshire and Litchfield Counties for an elevated risk for fire spread for today.

Behind the cold front, cooler and drier air will return for Wednesday. RH values will be as low as 25 to 40 percent during the afternoon hours. Northwest winds will be around 10 to 15 mph with a few higher gusts in the morning but will be lowering by the afternoon hours. Depending on the conditions of fuels, a localized enhancement for elevated risk fire spread could occur in some areas on Wednesday. The next chance for rainfall will be Thursday night into Friday.

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