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650
FXUS61 KBTV 111130
AFDBTV

Area Forecast Discussion
National Weather Service Burlington VT
730 AM EDT Tue Jun 11 2024

.SYNOPSIS...
A gradual warming trend begins today, with highs reaching well
into the 80s on Thursday. A cold front brings the potential for
widespread showers and thunderstorms on Friday. Father`s Day
weekend looks gorgeous with plentiful sunshine and low humidity.
Summer like warmth and humidity looks to return early next week.

&&

.NEAR TERM /THROUGH WEDNESDAY/...
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As of 728 AM EDT Tuesday...Forecast remains largely on track.
Forecast challenge today remains how quickly we can get rid of
the stubborn cloud cover. Blended in some of the latest hi-res
sky cover guidance to hint at the potential for some down
sloping effect from the Adirondacks leading to partial sunshine
for the Champlain Valley during the afternoon hours.

PREVIOUS DISCUSSION...The main theme of the near term forecast
is the vertically stacked upper level low in the vicinity. Given
the recent rainfall, plenty of low- level moisture remains in
the boundary layer. However, there remains sufficient surface
pressure gradient between a 1016 mb high over the Midwest and a
1002mb low over Nova Scotia to prevent widespread fog
development. Only exceptions are across the higher elevation
above 1000 ft, such as Saranac Lake and Northeast Kingdom. Today
will be an improvement with highs expected to be several
degrees warmer than Monday. Expect highs to be in the mid 60s to
low 70s as overcast conditions give way to a mix of sun and
clouds by the afternoon hours. Most locations should stay dry
but CAMs do depict a 15 to 25 percent chance of showers, mainly
over the terrain in the Adirondacks and southern Greens, as well
as near the CT River valley.

Tonight, expect more in the way of fog development as greater
pockets of clearing should lead to better radiational cooling amidst
light and variable winds. Overnight lows are forecast to be in the
40s for the colder hollows and low to mid 50s elsewhere. Wednesday
should be the pick of the week with seasonable temperatures in the
low to upper 70s, more sunshine and light winds. Once again, most
locations should stay dry with the exception of terrain-driven
showers, mostly across the Adirondacks as well as along and east of
the Greens. Thunderstorms potential is almost nil given that the
instability is below the hail growth zone.
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&&

.SHORT TERM /WEDNESDAY NIGHT THROUGH THURSDAY/...
As of 324 AM EDT Tuesday...Wednesday night into Thursday night will
be warm with rising thicknesses. The humid air mass arrives
relatively late Wednesday night, and so it should just be slightly
above normal with temperatures in the upper 40s across the
Adirondacks and Northeast Kingdom, while the rest of the region will
primarily be in the 50s. But by early to mid-afternoon, people will
likely start noticing the increasing dewpoints, although it
shouldn`t feel oppressive in the mid 50s to lower 60s. 925hPa
temperatures will climb towards 21 C, and that reasonably suggests
80s. The warming will also be occurring in the mid-levels, and so
conditions will be stable. Little to no shower or thunderstorm
activity is expected on Thursday. Although, there may be a
prefrontal trough that starts to nose into the region close to 00z.
Some slight chance PoPs begin to creep in along the international
border as it approaches.

&&

.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
As of 324 AM EDT Tuesday...That prefrontal trough shifts east
overnight. Showers will be sustained by weak instability and modest
upper level forcing, although better dynamics will likely remain
north of the international border. NWP begins to deviate after this
point as the cold front slides south. As it`s moving south, an
embedded, vigorous shortwave will rapidly translate east. A
combination of overrunning moisture and diurnal instability will
generate an axis of moderate to locally heavy precipitation. So the
main question is how far south that cold front will be and what that
means for rainfall in our area. Probabilistic data suggests at a
threshold of 1 inch that coastal New England is the primary focus
(about 10% with a few deterministic models with streaks of 2-3" in
Massachusetts), but the spread regarding this swath of higher
precipitation Friday into Friday night is high. The range of
guidance for this strip of rain is from the coastline up to
Montreal. Assessing 500hPa clusters and various 250hPa wind fields,
there are differences even within clusters. Depending on how much
moisture is around, there could still be a handful of pop up showers
Friday, but it`s possible the front is too far south and the air too
stable that Friday could be mostly dry across the northern half of
our area. We`ll get in the range of higher resolution models soon
enough, but for now, the forecast for Friday is painted with a broad
brush of chance PoPs.

However Friday ends up, I can state more confidently that Saturday
and Sunday should be gorgeous for Father`s Day weekend. The air will
be seasonable (generally 70s to near 80 in the day and in the 50s at
night) with abundant sunshine beneath dry high pressure!

As surface high pressure moves offshore next Monday, a tropical
airmass will return to the region. This will send temperatures back
into the 80s across the region with high humidity... And then
probably some 90s as 925hPa temperatures climb towards 24-26 C. It
looks like we`ll be positioned near the edge of the developing upper
high, which will place us in the "ring of fire". So pop-up, hit-or-
miss showers and thunderstorms will make a return next Monday,
though with a cap and plenty of mid-level dry air likely present, it
will likely be more of a miss than a hit unless some type of
disturbance becomes apparent moving forward.

&&

.AVIATION /12Z TUESDAY THROUGH SATURDAY/...
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Through 12Z Wednesday...Widespread OVC through 12z this morning
with mainly MVFR ceilings except locally IFR at KSLK. Ceilings
lift to VFR between 15-18z today for most locations,
potentially not till 20z at KSLK. Winds are generally light and
variable for most of the TAF period, with the exception of
terrain-driven flow. After 04z Wednesday, there is the potential
for fog development and IFR conditions at KSLK and KMPV.

Outlook...

Tuesday Night: VFR. NO SIG WX.
Wednesday: VFR. Slight chance SHRA.
Wednesday Night: VFR. NO SIG WX.
Thursday: VFR. NO SIG WX.
Thursday Night: VFR. Chance SHRA, Slight chance TSRA.
Friday: Mainly VFR, with local MVFR possible. Likely SHRA, Slight
chance TSRA.
Friday Night: Mainly VFR, with local MVFR possible. Chance SHRA.
Saturday: VFR. NO SIG WX.
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&&

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

&&

$$
SYNOPSIS...Chai
NEAR TERM...Chai
SHORT TERM...Haynes
LONG TERM...Haynes
AVIATION...Chai