Sunrise 5:36 AM   Sunset 8:02 PM Moonrise 3:58 AM   Moonset 3:54 PM

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FXUS61 KBTV 042348 AFDBTV

Area Forecast Discussion National Weather Service Burlington VT 748 PM EDT Sat May 4 2024

SYNOPSIS
Dry weather will give way to widespread rainfall on Sunday along with breezy conditions. High pressure will bring dry and mostly sunny weather to start the new work week. The next chance for widespread rainfall and potential thunderstorms arrive middle of the week.

NEAR TERM /THROUGH SUNDAY NIGHT/
As of 722 PM EDT Saturday...Its a beautiful evening acrs our fa with partly cloudy skies and comfortable temps in the 60s to near 70F. Hope you enjoyed todays weather, because changes are on the way for Sunday. Have increased pops to 100% for Sunday as a widespread wetting rainfall is anticipated with qpf ranging btwn 0.25 and 0.75. A cool, raw and wet day is anticipated with localized breezy south/southeast winds likely from time to time. Did make some minor tweaks to cloud grids this evening, temps, and winds, but overall fcst in good shape.

Previous discussion follows: It has turned out to be a fairly pleasant early May day across North Country with upper ridging overhead mitigating the low- level maritime flow from coastal New England. KCXX radar shows some reflectivity returns across our southwestern and southern zones but much of these are just virga with plenty of dry air in the lower levels of the atmosphere. The partial sunshine has allowed temperatures to warm into the upper 60s to low 70s with even some isolated 73-74 degree readings despite plenty of cloud cover. Overnight tonight, the omega block weakens and moves east, allowing a piece of weak shortwave energy to come up the Ohio River valley. There are some hints of elevated instability, but while a handful of rumbles cannot be ruled out, it should be isolated enough to preclude mention of thunder with this forecast package.

Heading into Sunday, PWATs rise to around 1.5 standard deviations above normal as moisture with Gulf of Mexico origins overspreads the region. Upper level pattern shows a stout omega block shifting east of our area into Maine, increasing shower chances and coverage on Sunday. However, organized convection is not expected as the main jet energy associated with the shortwave trough moving eastward from the Great Lakes is diverted into Quebec. As a result, the main trough axis does not approach North Country until sometime middle of next week. Indeed, forecast soundings show a lack of surface-based instability, so scattered to numerous showers with brief locally heavy downpours look to be the main risk. While there could be embedded thunder due to elevated instability, the coverage is again too isolated to mention in the forecast.

While widespread wetting rainfall is expected, rainfall amounts are quite manageable in the 0.25 to 0.5 inch range with locally higher amounts in the favored upslope regions of the Green Mountains and Adirondacks. Indeed, the MMEFS shows none of our area rivers going into action stage. Sunday will be about 10-12F cooler than Saturday, with highs only in the 50s with low 60s possible if there are breaks in the rain or clouds. In addition, a 40-50 kt 925mb southerly low level jet overspreads the region during the day on Sunday. NAEFS situational awareness ensemble table shows the v vector wind rising up to 2.5 standard deviations above normal, so it will be a rather breezy if not blustery day. A mitigating factor is that the waters of Lake Champlain is still quite cold with water temperatures still in the low to mid 40s, which is almost isothermal to the forecast 925mb temperatures in the +5 to +8C range. That could reduce the mixing potential in the boundary layer, in addition to the stabilizing effect of any rainfall. So have mostly kept wind gusts in the 30 to 35 mph range across the Champlain Valley despite the southerly wind component being anomalously strong. Overall, no overall hazardous weather to speak of but Sunday does look to be a less than ideal day for outdoor activities. Heading into Sunday night, showers taper off and the boundary layer looks well mixed enough to preclude widespread fog development. Temperatures stay quite mild in the mid 40s to low 50s.

SHORT TERM /MONDAY THROUGH MONDAY NIGHT/
As of 307 PM EDT Saturday...A few showers could linger on Monday from a weak surface trough (QPF up to 0.03"), but precipitation chances decrease throughout the day as drier air moves in. With this dry air, clouds will be on the decrease as well on Monday, allowing for mostly sunny skies by the afternoon. Resulting highs will be in the mid 60s to lower 70s, a few degrees above average. Monday night, clouds will mostly clear out and winds will be light/variable as high pressure noses into the region from Hudson Bay. This will cause lows to drop into the 40s for most. It's possible for some patchy fog to develop late Monday night into early Tuesday morning with the favorable light winds and clearing skies. This will largely depend on how much the skies do clear as some models hold onto some clouds throughout the night.

LONG TERM /TUESDAY THROUGH SATURDAY/
As of 307 PM EDT Saturday...Ridging and surface high pressure will keep Tuesday dry and mostly sunny. There could be some high clouds arriving Tuesday afternoon/evening due to a trough hovering to our northeast as well as another approaching system. Tuesday is likely to be our warmest day of the long term period (through Saturday)
with highs in the upper 60s through mid 70s, several degrees above average.

Precipitation chances will return by Wednesday as one of a few waves follow the zonal flow aloft through the forecast area. Each day through the end of the week could have some showers. Highs will take a hit from these, mostly peaking in the 60s, and lows will be in the 40s and lower 50s for the remainder of the week. Frontogenetical forcing and instability look most favorable Wednesday for some thunderstorm chances, but instability and forcing are not impressive enough for severe weather concerns at this time.

AVIATION /00Z SUNDAY THROUGH THURSDAY/
Through 00Z Monday...VFR conditions are expected to prevail at all terminals for the next 6 to 12 hours. Some MVFR ceilings will be possible at KMPV as southwesterly flow brings low-level moisture and increased cloud cover into the region under a subsidence inversion. Outside KMPV, ceilings will gradually lower towards MVFR after 12Z as widespread precipitation moves across the region, with some pockets of IFR possible. Winds are currently under 10 kt out of the south or southeast, except for northeast at KMSS. Winds will become gusty during the afternoon, with LLWS possible at most terminals.

Outlook...

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

BTV WATCHES/WARNINGS/ADVISORIES
VT...None.
NY...None.

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