textproduct: Burlington

WHAT HAS CHANGED

As of 221 AM EDT Saturday...

No significant changes were made to the forecast.

KEY MESSAGES

As of 221 AM EDT Saturday...

1. High pressure will dominate the region today through early Sunday. Rain chances, mainly north, return during the day Sunday as a cold front sinks south from Canada.

2. A period of shower weather is expected mid to late week, with a emphasis on Wednesday night into Thursday.

DISCUSSION

As of 221 AM EDT Saturday...

KEY MESSAGE 1: High pressure will continue to build in this morning with areas of patchy valley fog scouring out an hour or two after sunrise. Mainly clear skies aside from some fair weather cumulus in the higher terrain will create a pleasant day across the region. Some light breezes from southwest channeled flow in the St. Lawrence Valley to 10-20 mph will be possible, in addition to light southerly flow in the Champlain Valley to 15 MPH as well. Highs will be relatively seasonable in the mid 70s. High pressure will begin to dip south late this evening as a cold front from Quebec sinks south. A modest low-level jet to 40-50 knots will precede the frontal leading to gusty winds on mountain summits. Elevations above 2500ft agl could see southwest winds around 30 MPH, with very isolated gusts to near 40 MPH in the highest summits of the Adirondacks. Due to less friction, Lake Champlain may also see 10-20 MPH winds overnight. An inversion should help keep winds in the wider valleys and sheltered hollows generally under 10 MPH.

Zonal flow ahead of a positively tilted shortwave, in association with the cold front, will keep moisture fairly progressive, but some shower activity will be possible near the International Border by mid to late Sunday. Lifting along the front with cool temperatures aloft may lead to some weak instability on the southern periphery of the front in northern Vermont and near the US-11 corridor in northern New York. The southern extent of the shower activity will be tricky with 10-20 degree dewpoint depressions Sunday afternoon as high pressure retreats south. Best shower chances will be closer to the International Border during the day. Rain amounts will generally be low from a few hundreths to a tenth or two in the western upslope areas. The front will slowly sag south Sunday night into north central Vermont and the northern Adirondacks. With fairly uniform flow under a zonal pattern, showers will become more confined to the western upslope regions of the Greens and Adirondacks than the wider valleys. The front will continue to push south early Monday, with models denoting it stalling out just south of our CWA from Lake Ontario into the Hudson Valley and curling to the Northeast towards Maine. Drier northern air will filter south into the area with a drying trend for Monday. Temperatures will also fall into the low to mid 70s with the cooler north air.

KEY MESSAGE 2: The weather pattern will feature channeled flow against a deep layer high in the southeastern US and a strong, compact upper low shifting slowly eastward across Canada. Systems with Pacific origins will get sucked into this fast flow bringing rounds of rain. Surface high pressure in far eastern Canada will try and keep warm, humid air from lifting northeastwards, and so we will be on the stable and dry side of things for the most part on Tuesday. We still should observe increased clouds and some rain along the southern portions of our forecast area. A stronger area of low pressure will develop over the Great Lakes region on Wednesday, and that should provide the focus for more active weather conditions. The interface of dry, stable conditions on the western periphery of departing high pressure and humid, modified tropical Pacific air will create the potential for showers and thunderstorms beginning late Wednesday afternoon. Elevated instability could allow thunderstorm activity to persist overnight before the system departs early Thursday morning. Synoptic scale models are starting to depict this feature as the one that produces most of our rainfall next week. Dynamically, the system appears quite vigorous and simulated IR satellite off the GFS is showing the potential for cool cloud tops associated with the elevated convection and strong isentropic lift. We'll continue to keep an eye on this feature.

AVIATION /06Z SATURDAY THROUGH WEDNESDAY/

Through 06Z Sunday...Skies are mainly clear. Localized fog has been reported at KSLK and KMSS for short windows of time, as dry air is competing with otherwise favorable conditions for radiation fog. Visibility could be in and out of IFR for a few hours at KSLK before prevailing IFR closer to sunrise, and perhaps an hour or two delayed at KMPV given drier air present there. After 12z, fog will dissipate with slowly increasing south to southwest to the west of the Green Mountains while staying more west to northwest near KMPV, KEFK, and KRUT. Wind speeds will increase to 6 to 10 knots in the afternoon with gusts 15 to 19 knots possible, mainly at KMSS. Surface winds will decrease after 22z, though winds at 2000 ft agl will begin to increase ahead of a front descending southwards on Sunday. LLWS has been noted across far northern terminals beginning around 03-04z Sunday.

Outlook...

Sunday: VFR. Chance SHRA, Slight chance TSRA. Sunday Night: Mainly VFR, with local IFR possible. Chance SHRA. Monday: Mainly VFR, with local MVFR possible. NO SIG WX. Monday Night: VFR. Slight chance SHRA. Tuesday: Mainly VFR, with local MVFR possible. Chance SHRA, Slight chance TSRA. Tuesday Night: Mainly MVFR, with local VFR possible. Likely SHRA, Slight chance TSRA. Wednesday: MVFR. Chance SHRA, Slight chance TSRA.

BTV WATCHES/WARNINGS/ADVISORIES

VT...None. NY...None.