textproduct: Burlington

WHAT HAS CHANGED

As of 220 AM EDT Thursday...

No changes to the current forecast.

KEY MESSAGES

As of 220 AM EDT Thursday...

1. Increasingly mild, breezy, and showery weather is expected through Friday in advance of a cold front. Sharply drier and sunny weather will return on Saturday.

2. Fluctuating temperatures next week with a few chances of scattered showers.

DISCUSSION

As of 220 AM EDT Thursday...

KEY MESSAGE 1: Current surface analysis this morning shows a weak shortwave continuing to push east across the region. Most radar returns are not making it to the ground as a result of a decent surface dry layer. That said, isentropic lift across the southern tier of New York is leading to some light shower activity that stretches back into the Great Lakes. As today progresses this boundary will lift north encountering a dry sfc-700mb level which will help reduce precipitation chances for the most part today. Clouds will be the main change as cloud cover increases throughout the day. A few isolated light showers and/or sprinkles in northern New York, and some upslope mist and mountain top clouds will be possible after noon today, but most locations today look to remain dry. The main weather impacts today will be wind driven. A tightening pressure gradient will allow for good southerly channeled flow in the Champlain Valley and St. Lawrence Valley this afternoon as a 40-50 knot LLJ in the 850-925mb layer builds across the region. Gusts 20-30 MPH are expected late this morning into this evening before more steadier rain arrives late tonight, stabilizing and weakening our gusts. While current lake winds are just below Lake Wind Advisory criteria (25 knots), a Lake Wind Advisory will likely be needed for this afternoon and evening, when winds are expected to increase. Southerly flow will also aid in advecting some warmer air into the region, as highs increase into the upper 60s to low 70s today.

Steadier rain will arrive overnight tonight as a cold front pushes into the region from west to east. Moisture associated with this front is reminiscent of a summer-like pattern, as this air mass originates from the tropical east Pacific. PWs will increase to 1.5- 1.8" in the wider valleys of the area; in the 99th percentile for this time of year. While PWs will be anomalously high, the stretching the system, in addition to its progressive nature, will help keep higher totals at bay. Ensembles continue to keep probabilities of exceeding 1" at 10% or lower. Hi res model guidance generally depicts a quarter to half an inch of rain for much of northern New York, and near the International Border, with a quarter or less in the western Champlain Valley and southern Vermont, due to some shadowing effects. The winners from this system will be across the northwestern upslope regions of the Adirondacks and northern Greens where around three quarters of an inch is expected. Given the high PWs, some downpours, and locally heavier rainfall amounts will be possible in the aforementioned locations.

A secondary clearing cold front, depicted in the higher resolution models looks to pass through Friday afternoon. Some additional convergent flow and meager instability may allow for some additional showers across southern Vermont, though these look isolated to scattered at best. Dewpoints behind this second front will fall from near 60 Friday afternoon, to the upper 30s to low 40s by Saturday afternoon. Drying top down Friday night into Saturday will clear the region of cloud cover with more sunny skies. Temperatures will also follow suit, cooling from the mid 60s on Friday to the upper 50s to near 60 by Saturday. More seasonable temperatures will continue into the latter portion of the weekend.

KEY MESSAGE 2: Closed low across Hudson-James Bay this weekend will rotate a few shortwaves that will impact our area late weekend into next week.

The first largely stays across Canada with an associated cold front from the primary surface low well north in Canada moving across the northern Great Lakes then northern NY-New England Sunday night but immediately on its heels a larger, stronger and more amplified shortwave drops SSE into the region on Monday with much colder air and breezy conditions.

The initial front may bring a shower/two across the northern border but then the front waits for the more robust system during Monday with increased instability due to strong cold air advection aloft for better chance of showers, especially terrain driven.

Continued cold air advection and cyclonic NW flow Monday night will keep some clouds and gradient so not the coldest night.

Upper level shortwave ridging and surface high building into the region Tue-Tue ngt will bring the coldest air of this young season with frost-freeze likely everywhere except immediately along Lake Champlain. Tuesday morning lows will be in the 20s-30s with highs in the 50s with some upper 40s as well.

Ridging at all levels exits Wednesday with return flow and moderating temperatures and a chance of showers Wed ngt.

AVIATION /06Z THURSDAY THROUGH MONDAY/

Through 06Z Friday...Mainly high clouds across the region with calm/lgt surface winds and decent low level moisture. However, soundings show decent wind above the deck and this should prevent fog across NY and west of the Green Mountains. KMPV went to IFR due to Vsby and CIG but expect Vsby to improve as gradient shifts east yet stratus deck may linger so IFR-MVFR there through daybreak.

Light southerly winds increase and become more southwesterly in some spots with wind speeds 7 to 13 knots sustained with gusts 16 to 22 knots. As winds start subsiding around 20-21z, LLWS will be possible, mainly over KMSS and KSLK then spread east beyond 00z Friday. Additionally, some isolated rain showers may reach Adirondacks in the 16-20z timeframe.

Main shower activity with potential MVFR conditions enter KMSS around 00z with KSLK around 04z and after 06z Fri east.

Outlook...

Friday: Mainly VFR, with areas MVFR possible. Likely SHRA. Friday Night: VFR. Slight chance SHRA. Saturday: VFR. NO SIG WX. Saturday Night: VFR. NO SIG WX. Sunday: VFR. NO SIG WX. Sunday Night: Mainly VFR, with local MVFR possible. Slight chance SHRA. Monday: MVFR/IFR conditions possible. Slight chance SHRA.

BTV WATCHES/WARNINGS/ADVISORIES

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