Area Forecast Discussion
Issued by NWS Burlington, VT

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FXUS61 KBTV 231952
AFDBTV

Area Forecast Discussion
National Weather Service Burlington VT
352 PM EDT Mon Oct 23 2017

.SYNOPSIS...
A deep trough of low pressure over the Ohio Valley this afternoon
will shift into the Great Lakes tonight and Tuesday providing the
North Country with a windy and wet Tuesday and Tuesday night. The
rain will end from west to east during the early morning hours on
Wednesday, with total rainfall in the 1 to 2 inch range over much of
the area.

&&

.NEAR TERM /THROUGH TUESDAY NIGHT/...
As of 350 PM EDT Monday...Forecast for tonight through Tuesday
night remains largely unchanged from our thinking from yesterday
and last night with a few minor modifications due to recent
model trends.

Big picture highlights strong high pressure anchored off the
eastern seaboard while a deep upper trough is digging into the
Ohio Valley this afternoon. As the low strengthens and shifts
north/northwestward into the Great Lakes, the attending frontal
boundary will tap into sub-tropical moisture from the Gulf of
Mexico, readily seen on today`s blended TPW products. Some of
this deeper moisture is already working into the region this
afternoon with surface dewpoints rising into the mid 50s, and a
low marine stratus layer working up the southern Champlain and
Connecticut River valleys. As the front tracks through the
region late tonight through Tuesday, the deep moisture combined
with strong surface to mid-level winds paralleling the front
will develop a band of moderate to locally heavy rain moving
over northern New York during the morning hours, and Vermont in
the afternoon and evening.

Ahead of the front, winds will continue to become increasingly
gusty with the mean 925mb flow from the south/southeast
strengthening to 40-50kts. With a more southerly component to
the direction versus southeast, true downslope effects won`t be
realized despite gusts in the 30-40mph range. The wind combined
with falling leaves could present an issue with clogged drains
in urban areas, especially considering QPF should be fairly
widespread in the 1-2" range. Rivers should be able to handle
the QPF, so don`t think we`ll have any concerns there.

&&

.SHORT TERM /WEDNESDAY THROUGH THURSDAY/...
As of 350 PM EDT Monday...Models continue to show the back edge
of precipitation associated with cold front exiting central and
eastern VT on Wednesday. With the 500mb trough lagging behind
flow will generally be parallel to the front, making for a more
gradual end to rain showers across central and eastern VT. SW
flow behind the front could also filter in moist air and clouds
from Lake Ontario with just a slight to low chance of some
showers over the Adirondacks into the Champlain Valley late
Wednesday into Wednesday night. The aforementioned 500mb trough
looks to swing through the area sometime Thursday, keeping
chance of showers over the North Country.

Temperatures running 5-10 degrees above normal Wednesday and
Wednesday night will cool to near to slight above normal on
Thursday.

&&

.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
As of 350 PM EDT Monday...12Z ECMWF is slower to progress the
500mb trough eastward, keeping chance of showers over eastern
portions of the North Country Thursday night, while the GFS
shows slight ridging and PWATs falling to less than half an
inch. Friday looks to be dry with increasing southerly flow
ahead of another system approaching from the west. Models
diverge on evolution of this system and its upper level support
as we head into the weekend. At this point in time, Saturday
looks to be mostly dry with a longwave trough digging south and
east into the western Great Lakes region Saturday night.
Potential development of a coastal closed low at the surface
Sunday could bring warm moist air into the Northeast Sunday into
Monday. Chance of showers continues into Monday night. Above
normal temperatures are expected throughout the period.

&&

.AVIATION /20Z MONDAY THROUGH SATURDAY/...
Through 18Z Tuesday...VFR conditions will continue across the
region through sunset, and largely prevail at most terminals
through 12Z Tuesday, with the exception being KMPV where marine
MVFR stratus advecting northward will build into eastern Vermont
after 02Z. Elsewhere, expanding cirrus deck will just gradually
lower through the night. After 12Z, low clouds shift into
portions of northern New York, mainly affecting KPBG while rain
shifts over KMSS and KSLK, but not eastward until closer the end
of the 24hr period. Winds will continue to be increasingly
gusty from the south/southeasterly in the 15-25kt range through
12Z, strengthening to 25-35kts east of KMSS thereafter.

Outlook...

Tuesday Night: VFR. Windy with gusts to 30 kts. Definite RA.
Wednesday: VFR. Chance SHRA.
Wednesday Night: VFR. Slight Chance SHRA.
Thursday: VFR. Chance SHRA.
Thursday Night: VFR. Slight Chance SHRA.
Friday: VFR. NO SIG WX.
Friday Night: VFR. Slight Chance SHRA.
Saturday: VFR. Chance SHRA.

&&

.MARINE...
A lake wind advisory is in effect through at least Tuesday.
Winds will be from the south at 15 to 30 knots tonight, but
increase into the 25 to 35 knot range on Tuesday. Winds of this
magnitude will create rather choppy conditions, especially on
the northern portions of the lake, and waves will build into the
4 to 6 foot range by Tuesday.

&&

.EQUIPMENT...
MPV is not transmitting due to a communications outage. FAA is
aware of the problem. We do not have an estimated return to
service.

&&

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

&&

$$
SYNOPSIS...Lahiff
NEAR TERM...Lahiff
SHORT TERM...KGM
LONG TERM...KGM
AVIATION...Lahiff
MARINE...Evenson
EQUIPMENT...BTV



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