Area Forecast Discussion
Issued by NWS Burlington, VT

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FXUS61 KBTV 260542
AFDBTV

Area Forecast Discussion
National Weather Service Burlington VT
Issued by National Weather Service ALBANY NY
142 AM EDT Tue Sep 26 2017

.SYNOPSIS...
Strong high pressure at the surface and aloft will continue to
provide unseasonably warm, record setting temperatures for the
region through Wednesday. A cold front will cross the area
Wednesday night along with a chance of showers. Much cooler,
more seasonable weather is expected behind this front to round
out the week.

&&

.NEAR TERM /UNTIL 8 AM THIS MORNING/...
As of 1249 AM EDT Tuesday...High pressure remains in control
early this morning with clear/mostly clear skies and light to
calm winds as radiative mist and fog is forming across the
forecast area. The fog will be locally dense in the Champlain
Valley, eastern VT near the CT Valley, portions of the St
Lawrence Valley, and the favored climo locations in the northern
Adirondacks such as Saranac Lake. Mins will be much above
normal for late Sept in the anomalously warm air mass with lows
mainly in the mid 50 to mid 60s.

The mist/fog should burn off shortly after 8 am /8-10 am time
frame/ with the strong subsidence from the high and plentiful
sunshine.

&&

.SHORT TERM /8 AM THIS MORNING THROUGH 6 PM WEDNESDAY/...
As of 1249 AM EDT TUESDAY...

Another rinse and repeat day is expected with mainly sunny
skies outside a few passing thin high clouds. H850/H925
temperatures are perhaps a half degree cooler than today, but
should have little impact to high temperatures with values once
again topping out in the mid 80s across elevated terrain to the
lower 90s in the deeper valleys. See climate section below for
specific records. Then clear to partly cloudy by Tuesday night
under light winds and patchy fog in favored locales. Lows again
mainly in the 55 to 65 range.

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 MONDAY/...
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 /06Z TUESDAY THROUGH SATURDAY/...
High pressure at the surface and aloft will be over the
region today into tonight. Another round of radiational mist/fog
due to clear/mostly clear skies and light to calm winds is
expected this morning.

Expecting locally dense fog with IFR/LIFR/VLIFR conditions at
several of the TAF sites this morning including KMSS, KSLK,
KMPV, and KRUT. The LIFR/VLIFR conditions will be dominate
between 07Z-14Z at those locations. Expect VFR or MVFR
conditions at KBTV and KPBG with some patchy light mist
especially between 08Z-12Z. Expect the fog/mist and or low
stratus to burn off quickly between 12Z-14Z with the strong
subsidence with the ridge and abundant sunshine. The fog may
linger the longest at KMPV.

VFR conditions will dominate from the late morning through the
afternoon with some sct-bkn cirrus and a few-sct cumulus clouds.
The clouds will thin towards sunset with some lingering
scattered cirrus.

The winds will be mainly calm early this morning, and then will
be from the southeast to southwest at 6 kts or less during the
late morning through the afternoon, and will be light to calm
tonight.

Outlook...

Tuesday Night: VFR. NO SIG WX. PATCHY FOG.
Wednesday: VFR. Chance SHRA.
Wednesday Night: VFR. Chance SHRA.
Thursday: VFR. Slight Chance SHRA.
Thursday Night: VFR. NO SIG WX.
Friday-Saturday: VFR. Slight Chance SHRA.

&&

.CLIMATE...
Record high temperatures and year recorded for the period
through 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...WasulaEvenson/JMG
NEAR TERM...Wasula
SHORT TERM...JMG/Deal
LONG TERM...Deal
AVIATION...Wasula
CLIMATE...BTV



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