Area Forecast Discussion
Issued by NWS Burlington, VT

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000 FXUS61 KBTV 081726 AFDBTV Area Forecast Discussion National Weather Service Burlington VT 126 PM EDT Sat Aug 8 2020 .SYNOPSIS... Scattered showers and thunderstorms will develop across the higher elevations of the Green and Adirondack Mountains this afternoon. These showers will taper off this evening with loss of heating and drier weather will continue tonight and Sunday. A warming trend will start on Sunday as highs warm into the lower to mid 80s. We could see places in the Champlain and St. Lawrence Valley push 90 degrees once again as early as Monday with above normal temperatures expected through next week. Drier weather will continue through the first half of next week before wetter and unsettled weather makes a return on Wednesday. && .NEAR TERM /THROUGH SUNDAY/... As of 942 AM EDT Saturday...Cluster of thunderstorms with locally heavy rainfall currently weakening and slowly exiting southern portions of Rutland/Windsor Counties. MRMS/HPE 3 hourly estimates along with surface observations suggest totals up to 2.5 inches have occurred in this area since 600 am and a Special Wx Statement for localized flooding remains in effect until 10 am. Any flooding should be isolated and minor, if it does occur. As such, increased PoPs and cloud cover in this area through late morning as activity exits. Otherwise, going forecast remains in decent shape with a partly to mostly sunny skies, seasonably warm temperatures, modest humidity and a few late afternoon showers/storms. Latest CAM output suggests highest probabilities of a late day storm to occur along the western Lake Champlain lake breeze in eastern Clinton/Essex Counties, NY where convergence occurs with light westerly geostrophic flow aloft along with a modest low level upslope component. Have a great day! Previous Discussion... A few showers moved across southern Vermont as weak PVA led to some decent upward vertical motions. However, the environment has remain highly capped leading to these showers to be short- lived and very light in nature. We will see any lingering shower activity shift eastward shortly after sunrise as a shortwave trough swings through the region. Another very nice summer afternoon is in store for the North Country as we see partly sunny skies prevail across the region with highs once again in the upper 70s to lower 80s. We will see some showers and possibly a thunderstorm or two form over the high peaks of the Adirondack and Green Mountains today as we have a pocket of colder air aloft underneath the aforementioned shortwave trough. With the colder air aloft, our lapse rates this afternoon will aid in creating a few hundred J/kg of CAPE. While we could see a few of these thunderstorms ultimately become rooted in the boundary layer, a loft of the instability will remain elevated. This basically means we could have some brief moderate rainfall and a few rumbles of thunder without the concern of any hail or strong wind gusts. Any convection that does fire this afternoon will quickly dissipate this evening with the loss of diurnal heating. Quieter weather is expected tonight and again on Sunday as a weak shortwave tracks just north of the international border. Temperatures warm into the lower to mid 80s on Sunday which looks to be the first day of a warming trend as we head into next week. && .SHORT TERM /SUNDAY NIGHT THROUGH MONDAY/... As of 346 AM EDT Saturday...A compact shortwave will skirt the northern part of the forecast area Sunday night, so can`t rule out a shower or two overnight near the Canadian Border. The rest of the forecast are should remain dry overnight. Lows will be in the low to mid 60s. Once the shortwave moves downstream by midday Monday, increasing heights will keep the area mainly dry for the remainder of the day with the exception of a few showers possible over the northern Adirondacks. No large-scale forcing present, however will see warm air advection and moisture advection through the day on westerly flow, which will increase instability to the point where a few showers may be able to pop up over higher terrain once the ridge axis moves to our east. Highs Monday will be in the mid to upper 80s. && .LONG TERM /MONDAY NIGHT THROUGH FRIDAY/... As of 346 AM EDT Saturday...Flow turns increasingly southwesterly Tuesday, ushering in warmer, moist air from the Ohio River Valley to the North Country. Will see increasing instability Tuesday as temperatures rise to near 90 and dewpoints rise into the upper 60s/low 70s. Focused forcing for ascent arrives Tuesday night as a front moves crosses the forecast area from west to east. At this point, it looks like the front will move through overnight, which will limit instability and decrease the t-storm potential. However, if the timing shifts either way, could see an increase in t-storm threat. Deep layer shear is marginal, so not expecting any organized severe storms regardless of the exact timing of the frontal passage. The front may stall over our forecast area into Wednesday, and if the boundary remains overhead Wednesday afternoon, would see a better chance for some (mainly non-severe) t-storms. However, if the boundary were more progressive, chances for showers and thunderstorms Wednesday would decrease. The remainder of the week is a bit tricker to forecast, as the area will remain close to the border between Canadian high pressure to our north and more unsettled and unstable conditions to our south. It continues to appear that we will remain on the northern side of this boundary...thus have kept the forecast mainly dry to finish out the work week...however this may change if the boundary were to shift northward into our forecast area. Higher confidence in dry weather in the northern part of our CWA, slightly lower confidence in dry weather over southern VT. && .AVIATION /18Z SATURDAY THROUGH THURSDAY/... Through 18Z Sunday...Mainly VFR through the TAF period. SCT/SKC conds expected through 07Z with cumulus bases in the 050-080 AGL range. An isolated shower/storm possible through 01Z across elevated terrain, but paucity of coverage warrants no mention in the terminal forecasts at this time. SCT/BKN mainly mid-level cigs in the 070-150 AGL then arrive after 07Z Sunday with an outside shot of a shower at KMSS after 14Z. Some brief MVFR/IFR br/fg possible at KMPV/KSLK in the 07-12Z time frame but confidence only moderate. Winds generally variable and less than 10 kts through the period, governed heavily by terrain and/or lake breeze flows. Outlook... Sunday Night: Mainly VFR, with local MVFR possible. Slight chance SHRA. Monday: Mainly VFR, with local MVFR possible. Slight chance SHRA, Slight chance TSRA. Monday Night: VFR. Slight chance SHRA. Tuesday: VFR. Likely SHRA, Slight chance TSRA. Tuesday Night: VFR. Chance SHRA. Wednesday: VFR. Slight chance SHRA, Slight chance TSRA. Wednesday Night: VFR. NO SIG WX. Thursday: VFR. Slight chance SHRA, Slight chance TSRA. && .BTV WATCHES/WARNINGS/ADVISORIES... VT...None. NY...None. && $$ SYNOPSIS...Clay NEAR TERM...Clay/JMG SHORT TERM...Duell LONG TERM...Duell AVIATION...JMG is the U.S. government's official web portal to all federal, state and local government web resources and services.