-- Discussion containing changed information from previous version are highlighted. --
726
FXUS61 KBTV 120547
AFDBTV

Area Forecast Discussion
National Weather Service Burlington VT
147 AM EDT Wed Jun 12 2024

.SYNOPSIS...
A partly cloudy sky will persist overnight with some patchy fog
possible in the deeper valleys as temperatures fall back into
the 50s. Wednesday will feature intervals of clouds and sun with
a few widely scattered showers across the higher terrain. Much
warmer and drier weather returns briefly for Thursday, before a
cold front produce another round of showers on Friday. A
beautiful weekend is on tap with plenty of sunshine and
comfortable temperatures.

&&

.NEAR TERM /THROUGH THURSDAY/...
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As of 140 AM EDT Wednesday...Forecast remains largely on track
so only made minor changes to bring it up to date with current
obs. Temperatures are rather uniform across the region,
generally in the 50s under a broken to overcast cloud deck of
2000 to 3500 ft, with the exception of clear skies over the
Champlain Valley. Areas of patchy fog could still develop, but
the odds of more widespread fog have diminished with the cloud
cover overhead.

Previous Discussion...Mid/upper lvl closed cyclonic circulation
has redeveloped over eastern NY per latest GOES-16 water vapor
imagery and RAP upper air analysis, while dry air aloft prevails
acrs our cwa. However, shallow moisture and instability per
sounding data has resulted in plenty of strato cumulus clouds
acrs our cwa this aftn, with a few pockets of clearing acrs the
CPV and parts of central VT. Soundings show intervals of shallow
moisture btwn 975mb and 850mb acrs our cwa overnight, which wl
result in some partial clearing. Where areas of clearing
develop, patchy fog is possible, given light winds and temps
approaching cross over values. Lows similar to previous couple
of night with values in the mid 40s to mid 50s. On Weds, a weak
vort and slightly better moisture/instability, especially
northern VT and parts of the NEK wl help in the development of
widely scattered showers. Have continued with pops in the 15-25%
range for NEK VT and 15-20% probs for the dacks. Any showers wl
have limited vertical structure given sfc based CAPE values
<500 J/kg, but shower motions wl be <10 knots. So a few
localized heavy downpours are possible, but majority of the area
should remain dry. Highs on Weds should be warmer based on
progged 925mb temps btwn 14-15C, supporting values in the upper
60s to mid 70s. Weds night any showers quickly dissipate by
sunset with clearing skies and mostly light south/southwest
winds. Some patchy fog is possible eastern VT and parts of NEK
of VT, where better potential for rain showers occurs on Weds.
However, have noted increasing south/southwest flow by 06z,
especially western CWA, which may limit potential. Have not
included in fcst attm. Temps are similar to previous couple of
night with lows upper 40s to upper 50s.
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&&

.SHORT TERM /THURSDAY NIGHT/...
As of 353 PM EDT Tuesday...Expect above normal highs on Thursday with
temperatures surging into the low to mid 80s, although warming could
be delayed slightly if there is any morning fog in eastern Vermont.
There will be a lot of dry air aloft through the day on Thursday
that will help keep instability low despite ample low level warm air
advection. A modest pressure gradient will result in breezy south to
southwesterly wind, with gusty conditions becoming increasingly
favorable in the afternoon hours as boundary layer deepens. Forecast
soundings show mixing above 700 millibars where wind speeds will be
in excess of 30 MPH, supporting peak gusts in the 20 to 25 MPH range
in many locations. The temperature difference between the air and
lake should minimize the mixing on Lake Champlain and other larger
lakes, generally keeping wind speeds lower than over land during the
afternoon/evening. Low level wind will be channeled in the St.
Lawrence Valley where gusts above 30 MPH are favored at times. A
shower with a slight chance of thunder remains possible towards
sunset in this region, but most model guidance at this time suggests
a pre-frontal trough will still be too far west to support
precipitation even in our western areas through the daytime hours.

After that time, a vigorous shortwave trough that is currently in
southern British Colombia is progged to approach our region with
relatively good agreement across deterministic model guidance. This
upper level forcing combined with a surface trough will trigger
showers overnight. Forecast soundings show elevated instability that
suggests some rumbles of thunder will be possible, with best chances
in the predawn hours moving from west to east. Greatest PoPs
continue to be over northern New York and far northwestern Vermont,
with generally lower chances of these showers heading south and east
as best upper level forcing tends to shift north of due east as the
trough crosses our region. While rain showers could produce heavy
rain, rainfall amounts will be be modest. Deep layer shear looks
more perpendicular than parallel to the trough axis, suggesting the
heavy rainfall threat is minimal as showers will move along steadily
without backbuilding or training. Temperatures will be rather warm
overnight with continued southerly flow and increasing cloud cover,
with rain-cooled air still supporting lows mainly in the 60s.

&&

.LONG TERM /FRIDAY THROUGH TUESDAY/...
As of 353 PM EDT Tuesday...A cold front, following the pre-frontal
trough that moved through Thursday night, will quickly follow Friday
morning. Have kept a slight chance of thunder, although timing of
the front suggests relatively higher chances of a thunderstorm
exists in south central Vermont where temperatures have a better
chance to recover into the 80s before cooler and drier air advects
in behind the front. Overall, no significant weather is expected on
Friday, with a transition to a cool/dry pattern taking place in time
for Father`s Day weekend.

Temperatures will be chilly Friday and Saturday night, with the
latter night particularly cold for mid-June. Have bumped low
temperatures down a bit especially in the western Adirondacks where
patchy frost is not out of the question.

Dry and seasonable conditions will trend towards warm and muggy
early next week. While there is some model disagreement on the
extent of the heat for Tuesday, uncomfortably hot weather is likely
to develop midweek based on most model scenarios. The latest NBM
mean maximum temperatures are in the upper 80s to low 90s across
northern New York and Vermont; if dew points average in the mid 60s
as currently forecast, we could see heat indexes peak in the low to
mid 90s on Tuesday. Expect to see heat advisories concurrent with
major (3 out of 4) HeatRisk level if trends continue.

&&

.AVIATION /06Z WEDNESDAY THROUGH SUNDAY/...
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Through 06Z Thursday...Widespread cloud cover remains stretched
across our forecast area during the Wednesday pre dawn hours,
with a mix of VFR and MVFR ceilings being reported. Patchy fog
is still possible through 12z this morning but TAF sites should
generally stay AOA 6 SM. Ceilings lift to VFR for all sites by
15z this morning. Winds are generally light and variable or
terrain based for the TAF period.

Outlook...

Wednesday Night: VFR. NO SIG WX.
Thursday: VFR. NO SIG WX.
Thursday Night: VFR. Chance SHRA, Slight chance TSRA.
Friday: VFR. Chance SHRA, Slight chance TSRA.
Friday Night: VFR. NO SIG WX.
Saturday: VFR. NO SIG WX.
Saturday Night: VFR. NO SIG WX.
Sunday: VFR. NO SIG WX.
-- End Changed Discussion --

&&

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

&&

$$
SYNOPSIS...Taber
NEAR TERM...Chai/Taber
SHORT TERM...Kutikoff
LONG TERM...Kutikoff
AVIATION...Chai/Storm