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-- Discussion containing changed information from previous version are highlighted. --
814
FXUS61 KBTV 251736
AFDBTV

Area Forecast Discussion
National Weather Service Burlington VT
Issued by National Weather Service ALBANY NY
136 PM EDT Mon Sep 25 2017

.SYNOPSIS...
-- Changed Discussion --
Plenty of sunshine with some clouds across the higher terrain as
temperatures climb into the mid 80s to lower 90s. A shower or
two may pop up along the spine of the Green Mountains this
afternoon. The above normal temperatures will continue right
through the middle of the week as high pressure remains over the
area. Expect dry weather on Tuesday but as a trough of low
pressure moves into the region late Wednesday through Thursday
morning the chances for showers will increase...especially near
the Canadian Border.
-- End Changed Discussion --

&&

.NEAR TERM /THROUGH TUESDAY/...
-- Changed Discussion --
As of 129 PM EDT Monday...Diurnally driven cumulus field per the
GOES16 data was well underway across the higher terrain,
especially across the Greens. While current radar scans are null
of activity, recent trends in the satellite imagery suggest more
of the robust cumulus where dewpoints were well into the 60s and
near 70F could be enough for a shower or two to develop. In
fact, HRRR/NAM3km and BTV4 mesoscale model showing on
consecutive runs the potential for some isolated convection over
the Green Mountains this afternoon. Plenty of instability and
the mountains of course are a natural source of lift. Cap
overall should hold...but cannot rule out a couple can break
through the cap. Flow aloft is weak so any showers would not be
able to move off the terrain...thus having little impact
overall. Have included a slight chance of showers for parts of
the Green Mountains.

Any showers quickly come to an end tonight and high dew points
will keep overnight lows above normal and should see fog
developing with clear skies and light winds. On Tuesday once
again little change in 925/850 millibar temperatures and will
continue to go with more record breaking temperatures with highs
in the mid 80s to lower 90s. Will be interesting if here at BTV
we can actually hit three straight days of 90 degrees...something
that never occurred this summer.
-- End Changed Discussion --

&&

.SHORT TERM /TUESDAY NIGHT THROUGH WEDNESDAY/...
As of 323 PM EDT Sunday...Its much of the same story for Tuesday
evening as the ridge will still be in place. High heat during
the day Tuesday and high dewpoints during the afternoon will
lead to fog overnight. General feeling is that there will be
some dense fog in the sheltered valley locations with some
patches of fog elsewhere. Overnight lows will be in the 60s
again, which is more indicative of our normals highs this time
of year.

The airmass will be slightly changing into Wednesday as the
ridge finally breaks down however not much changes in the thermal
profile until late. 925mb temps still support temps in the upper
80s with 90`s in the Valleys. I wasn`t as bullish on that as
we should start to build in some cloud cover that would
insulate the North Country from peak heating. Even so the
forecast of mid to upper 80s would still set or tie records at
BTV/MPV/MSS/1V4. With records possible I`ll hold on to the
previous discussion highlighting heat hazards below:

While these temps are considered sub advisory(<95 F), they are
not to be taken lightly especially given the time of year. Based
on the forecast and current records, its expected that records
will fall at all sites by 3-5 degrees. Prolonged exposure
outside combined with strenuous activity can lead to heat
related injuries. Please take caution, stay hydrated and take
frequent breaks during any outdoor activities. This will be the
fourth consecutive day with 90+ degree heat indexes during the
afternoon.

&&

.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
As of 323 PM EDT Sunday...Wednesday night is when we should
finally start to see some reprieve from the heat. A mid level
short wave will finally move into the North Country but the
moisture isn`t very strong. I`ve trended the forecast back
another 3-6 hours as guidance seemed overdone on the precip
threat during the late afternoon Wednesday.

A weak cold front will swing through during the overnight hours
Wednesday and bring scattered showers. Given the overnight
timing I dont feel there will be any thunder threat so I`ve
opted to continue with no mention of thunder. Behind the front
we get into cold air advection and see temps return to near
normal with highs in the 60s and lows in the 40s.

Late in the week heading into the weekend guidance is starting
to bring a shortwave trough into the region so I`ve mentioned
slight chance for pops but I dont have high confidence in
timing of the isolated to scattered showers.

&&

.AVIATION /18Z MONDAY THROUGH SATURDAY/...
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Through 18Z Tuesday...VFR conditions through about 06z before
fog returns at several sites through the overnight period.
Little in the way of cloud cover through the period, diurnally
driven FEW-SCT cumulus clouds, but brief periods of LIFR to
VLIFR ceilings associated with the fog...especially at KSLK and
KMPV. Winds will be less than 10 knots through the period.

Outlook...

Monday Night: VFR. Patchy FG.
Tuesday: VFR. NO SIG WX.
Tuesday Night: VFR. NO SIG WX.
Wednesday: VFR. Chance SHRA.
Wednesday Night: VFR. Chance SHRA.
Thursday: VFR. Slight Chance SHRA.
Thursday Night: VFR. NO SIG WX.
Friday: VFR. Slight Chance SHRA.
-- End Changed Discussion --

&&

.CLIMATE...
Record high temperatures and year recorded for the period Sunday Sep 24
to Wednesday Sep 27

Day    Burlington    Massena      Montpelier
9/25   85 / 1891     90 / 2007    85 / 2007
9/26   84 / 1934     82 / 1970    83 / 2007
9/27   83 / 1920     82 / 2003    80 / 2007

For Burlington, here are the latest in the year dates for reaching
specific temperature thresholds

90F or higher:  9/16/1939
88F or higher:  9/22/1965
87F or higher:  9/23/1895
86F or higher:  9/23/1895 (was 87F that day)

RECORDS:
Day   Burlington   Massena   Montpelier   St Johnsbury
9/23                 86
9/24     91          88         85          89* (Tied)

&&

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

&&

$$
SYNOPSIS...Evenson/BGM
NEAR TERM...Evenson/BGM
SHORT TERM...Deal
LONG TERM...Deal
AVIATION...Evenson/BGM
CLIMATE...BTV