Area Forecast Discussion
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FXUS61 KBTV 251804
Area Forecast Discussion
National Weather Service Burlington VT
204 PM EDT Sun Sep 25 2016
Tranquil early fall weather will persist through Monday, as a
large area of Canadian high pressure crosses the region. The crisp
air mass will allow areas frost to develop once again tonight,
with lows generally ranging through the 30s. Developing southerly
winds will allow for moderating temperatures on Monday, with high
temperatures reaching the mid to upper 60s in most valley
locations. A frontal system approaching from the west will bring
our next rainfall event Monday night into Tuesday.
.NEAR TERM /THROUGH MONDAY/...
As of 204 PM EDT Sunday...It`s another gorgeous early fall
afternoon across the North Country with temperatures warming into
the mid to upper 50s currently under sunny to mostly sunny skies.
Cyclonic flow from a departing trough continues to produce some
fair weather cumulus across Northeast Vermont, which will keep
temps down a bit in the low/mid 50s for highs, but elsewhere more
sunshine is being seen so temps will bump a few degrees from
current values to daily highs in the mid 50s to low 60s.
For tonight, surface high pressure extending from James Bays
southward into the Northeast very slowly drifts eastward,
continuing to crest over the region. Any lingering clouds across
northeast Vermont will trend towards clear, and with little
airmass change from last night and winds aloft lighter, we should
see even better radiative cooling conditions than this morning.
Despite 925-850mb temps warmer than last night, surface temps
area-wide should be a few degrees cooler producing more areal
coverage of frost. Have gone ahead and hoisted frost advisories
and freeze warnings for just about all of the BTV CWA, excluding
Grand Isle County where warmer Lake Champlain waters should keep
temps in the upper 30s to low 40s. Elsewhere, lows will widely
ranging through the 30s, with some upper 20s possible in the
Northeast Kingdom and locally low/mid 20s in the colder hollows of
the Northern Adirondacks (i.e. KSLK). In addition, unlike last
night where winds aloft mitigated fog development, expect to see
some patchy dense fog develop in the usual climo favored river
valleys after midnight.
On Monday, the aforementioned high shifts off the New England
coast allowing winds to shift to the south and temperatures to
warm to more seasonal values in the mid to upper 60s. We`ll start
the Monday under full sunshine with any morning fog burning off,
but as we progress into the afternoon we anticipate some
increasing mid and upper level clouds from west as a large closed
low approaches. Any rain showers associated with this system
should hold off until Monday night though.
.SHORT TERM /MONDAY NIGHT THROUGH TUESDAY/...
As of 422 AM EDT Sunday...A cold front will move east from the
Great lakes Monday night with rain showers developing over
northern New York. Expecting this rain shower activity to move
into Vermont mainly after 06Z Tuesday. Have gone with likely or
categorical pops. Models showing mid level dry slot to move into
the region early Tuesday morning over northern New York, and
across Vermont Tuesday morning. Expecting rain shower activity to
be over across the region by 18Z Tuesday, as mid level dry slot
will be over the region. The only exception to this will be over
the Saint Lawrence valley where models hinting at moisture moving
northeast from Lake Ontario, so have kept in slight chance pops
for showers there.
.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
As of 422 AM EDT Sunday...Models have a closed upper low over the
western Great Lakes Tuesday night, but GFS and ECMWF have vastly
different solutions as to the forecast track of this upper closed
low through Saturday. This leads to a rather low confidence
forecast, especially from Thursday through Saturday. Have gone
with a dry forecast across the region Tuesday night through
Wednesday night, as GFS and ECMWF in fairly good agreement on
this. ECMWF takes this closed upper low over the western Great
Lakes and moves it southward to the southern Appalachians and then
retrogrades it back to the western Ohio valley by early Friday
night, as an upper ridge builds northwest from the Atlantic across
New England and northern New York. The GFS model takes this upper
low over the western Great Lakes Tuesday night and moves it
southeast across the Ohio valley and into southern New England by
early Friday night. The ECMWF suggests a mainly dry forecast
Thursday and Friday across the region, while the GFS model hints
at a showery forecast from Thursday through Saturday. Have opted
to stay with the superblend pops from Thursday through Saturday
and have low chance pops for showers during this period. Given the
significant differences in the location of the closed upper low
during the period from the ECMWF and GFS models, forecaster
confidence is low through the long term period.
.AVIATION /18Z Sunday THROUGH Friday/...
Through 18Z Monday...Mainly VFR conditions are once again expected
through the period, with the typical exception being the high
likelihood of VLIFR in FG/FZFG at KSLK/KMPV from 05-13Z. North-
Northwest winds 8-10 knots with gusts 16-20 knots persist through
the daylight hours, then abates to nearly calm overnight.
Outlook 18z Monday through Friday...
18z Mon - 00z Tue: Mainly VFR.
00z Tue - 00z Wed: VFR trending to a mix of VFR/MVFR in scattered showers.
00z Wed - 00z Sat: Mainly VFR with isolated MVFR cigs.
VT...Freeze Warning from 1 AM to 8 AM EDT Monday for VTZ003-004-007-
Frost Advisory from 1 AM to 8 AM EDT Monday for VTZ002-005-006-
NY...Freeze Warning from 1 AM to 8 AM EDT Monday for NYZ026-027-
Frost Advisory from 1 AM to 8 AM EDT Monday for NYZ028-035-087.