textproduct: Burlington

WHAT HAS CHANGED

As of 603 PM EDT Tuesday...

Have issued an update this evening, mainly to add thunder chances to Wednesday's forecast. Model soundings indicate CAPE values of 250 to as much as 1000 J/kg tomorrow afternoon. This should be enough to allow for some thunder, even lacking strong forcing. Coverage of the showers/thunderstorms is uncertain, as some CAMs are showing two waves of precipitation with a substantial break in the middle, while others are more broad brushed. Regardless, with PWATs approaching 2 inches, briefly heavy rain will be possible, though no flooding is anticipated.

KEY MESSAGES

As of 209 PM EDT Tuesday...

1. Chances for scattered showers start early Wednesday and persist through Friday.

2. Building heat and humidity through Friday.

3. Cooler over the weekend into next week with a few shower chances.

DISCUSSION

As of 209 PM EDT Tuesday...

KEY MESSAGE 1: Surface and upper level ridges will exit our region later today, after a sunny and dry day. Some fog will be possible once again overnight, though not too extensive since we're a few days removed from rainfall. Our weather pattern will become more unsettled for the Wed through Fri timeframe as some upper level shortwave energy will pass overhead and bring chances for showers. Meanwhile we will have warming at the surface and temperatures surging to the upper 80s and lower 90s. This will lead to some surface based instability and some thunderstorms will be possible each afternoon. Best forcing will be on Friday as a surface front will also cross our region though the surface low will remain well north of our forecast area. As previous forecaster mentioned, not expecting a wash out but several chances for showers which should be tied to shortwaves passing through progressive upper level flow. At this time not expecting strong or severe storms.

KEY MESSAGE 2: Temperatures will trend warmer the second half of the work week with increasing humidity Thursday and Friday. Given the overall unsettled weather pattern with scattered showers and clouds moving through, have continued to hedge forecast temps towards MOS guidance, slightly lower than the NBM. Friday continues to look like the warmest day, when temperatures will reach into the upper 80s to lower 90s. At the same time, dewpoints will tick upwards into the mid to upper 60s as Gulf moisture wraps up and around high pressure over the western Atlantic. As a result, expect the airmass to feel noticeably more muggy late week. Heat indices will reach into the low to mid 90s on Friday in the Champlain Valley, Saint Lawrence Valley, and Connecticut River Valley. In addition to the increasing humidity and warmer daytime temperatures, overnight lows will also be on the warmer side, falling only to the low to upper 60s. This will limit overnight recoveries, and increase heat risk to any vulnerable populations.

KEY MESSAGE 3: Large scale troughing slowly builds into the region this weekend and into next week, gradually lowering temperatures and bringing multiple rounds of shower chances. While any concerns for heat headlines will end with the cold front on Friday, the trough and the associated cooler air will build in gradually so it will be longer before it feels fully refreshing. After any lingering showers clear sometime Friday night behind the first shortwave, Saturday looks to be mostly dry and still relatively warm. Highs look to be in the mid 70s to upper 80s. The next shortwave looks to come through late Sunday and Sunday night with another chance for showers, knocking the temperatures down a bit more behind it. By the start of next week, the dew points look to be in the 50s and highs look to be in the 70s and low 80s. Another shortwave with associated showers is possible for Monday or Tuesday. These shortwaves all look to be quick moving so there are currently not any flooding concerns.

AVIATION /18Z TUESDAY THROUGH SUNDAY/

Through 18Z Wednesday...VFR conditions will mostly prevail for the next 18 hours. The exception is that patchy fog formation is expected across parts of eastern Vermont late tonight. Whether it will be able to reach any specific terminal is uncertain, but there is a decent probability (maybe 60 percent) that it reaches MPV. Any fog exits around sunrise. Around and after 12Z tomorrow, rain showers enter the region from southwest to northeast. As the rain arrives, ceilings will fall and MVFR ceilings are possible at any of the terminals late in the morning and in the afternoon. WInds will generally be light and variable over the next 24 hours, but with BTV and PBG seeing southerly winds today.

Outlook...

Wednesday Night: Mainly VFR, with local IFR possible. Definite SHRA, Slight chance TSRA. Thursday: Mainly VFR, with local IFR possible. Chance SHRA, Slight chance TSRA. Thursday Night: Mainly VFR, with local MVFR possible. Slight chance SHRA. Friday: Mainly VFR, with areas MVFR possible. Chance SHRA, Chance TSRA. Friday Night: Mainly VFR, with local IFR possible. Chance SHRA, Chance TSRA. Saturday: VFR. Slight chance SHRA. Saturday Night: VFR. Slight chance SHRA. Sunday: VFR. Chance SHRA, Slight chance TSRA.

CLIMATE

Record High Temperatures:

June 12: KMPV: 88/2017 KMSS: 89/2005

Record High Minimum Temperatures:

June 12: KBTV: 71/2017 KPBG: 67/2017 KSLK: 62/1996

BTV WATCHES/WARNINGS/ADVISORIES

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