Area Forecast Discussion
Issued by NWS Burlington, VT

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FXUS61 KBTV 281419

Area Forecast Discussion
National Weather Service Burlington VT
1019 AM EDT Sun May 28 2017

Overall looking at a quiet day today with clouds building up
over the mountains and maybe a shower or two over the higher
terrain this afternoon. Most areas will remain dry with highs in
the 70s to around 80. The pattern will change late tonight and
especially on Memorial Day as clouds will be on the increase
along with the chances for rain showers.


As of 1019 AM EDT Sunday...Any lingering valley fog has eroded
this morning and most areas are seeing plenty of sunshine.
Starting to get some buildups over the higher terrain across
southern Vermont...and we should see some buildups over the
northern Adirondacks and remainder of mountains in Vermont as
the day wears on. Cannot rule out the possibility of a shower or
two over the higher terrain during the mid-late afternoon hours.
Threat is low given the limited instability and forcing. Highs
are on track today for 70s to around 80 as areas outside the
mountains see a good deal of sunshine. Have made minor changes
to sky and weather grids to match scenario just described.
Essentially lower sky cover and confining it more to the
mountains and limiting the shower threat to the mountains and
only keep precipitation chances in the slight chance category.
Rest of forecast remains untouched.

Previous Discussion...
Tonight will remain dry early before the mid-level ridge pushes
east after midnight. This will lead to mid/upper level low
progressing eastward into the Great Lakes region. A surface low
and shortwave trough will pivot through the region, dragging a
warm frontal feature and associated deep moisture through the
pre-dawn hours Monday with widespread showers developing through
the morning. Hi-res models still hint at with synoptic forcing
associated with mid-level WAA as it lifts north, there`s
potential a weak mid-level dry slot building in briefly during
the late morning to mid-day hours which could bring brief period
of reduced PoPs and the potential for some gusty southeast
winds along the northern slopes of the Adirondacks as well as
western slopes of the Green Mountains as a 925-850mb jet of
35-50 kts will be overhead. Thinking is still the same as the
previous shift, still not thinking this will be wind advisory
levels, but certainly gusts up to 40mph are quite possible.

The chance for strong winds will quickly subside Monday
afternoon/evening as a weak cold frontal boundary shifts
through area. With this we can expect to see another brief
round of showers and would not rule out a rumble or two of
thunder as well too.

Sunday night will see lows in the 50s, while monday will see
highs Monday slightly below normal in the low 60s and low 70s in
the western counties..


As of 418 AM EDT Sunday...Once 850mb warm front lifts to our
north and east late Monday, should see relatively quiet and mild
conditions for Monday night. Deep-layer low pressure anchored
north of the Great Lakes will maintain S-SW winds during the
overnight hrs. Best chance for PBL decoupling will be east of
the spine of the Green Mountains, where lows will generally
range from 45-50F. Across the Champlain and St. Lawrence
Valleys, should see lows in the low-mid 50s for Monday night,
with S-SW winds 10-15 mph at times.

On Tuesday, will see some modest 700-500mb height falls from
west to east as center of upper low moves eastward across
northern Ontario. Also, some indication of an embedded shortwave
trough moving newd from wrn NY into our region by late Tuesday
morning/early afternoon. 850mb thermal ridge is slightly more
pronounced in advance of this trough in the 00Z GFS as compared
to previous runs. Insolational heating may contribute to SBCAPE
values of 500-800 J/kg per 00Z NAM during Tuesday afternoon.
Dewpoints only in the lower 50s, but it appears ingredients are
sufficient for at least a slight chance of tstms heading into
Tuesday afternoon. Based on present timing, best sfc heating
should be across central/s-central VT, and that should coincide
with best chances of thunderstorms aftn hours Tuesday. High
temps generally in the lower 70s for valley locations.


As of 418 AM EDT Sunday...The long-term period will feature a
broad mid-upper tropospheric low centered in the mean across the
northern Great Lakes region into northern Ontario. The North
Country will be embedded within a belt of moderately strong,
cyclonically curved mid-upper level flow Tuesday night through
Thursday morning. While it is difficult to time individual vort
maxima within this flow, it appears their presence will be
frequent enough to result in periods of rain showers, especially
during peak afternoon heating on Wednesday. Some indication
that a shortwave ridge will briefly build across the region
Thursday afternoon, so will indicate lower PoPs for that period
(20-30%). A shortwave trough moving in from the Canadian
Prairies will reestablish the 500mb trough on Friday, resulting
in a better chance of showers with possible thunderstorms late
in the day Friday, with showers continuing into Friday
night/early Saturday based on present indications. In terms of
temperatures, should see readings relatively close to seasonal
normals as we move into early June. Will see valley highs in the
low-mid 70s (except upper 60s Thursday), with lows ranging from
the mid 40s to lower 50s.


Through 12Z Monday....VFR conditions expected overall for most
locations. KMPV is the lone exception, currently VLIFR, but
should clear rapidly by 13Z. Conditions will start to degrade
for western stations after 06Z ahead of a approaching warm
front as KMSS/KSLK start to see some intermittent MVFR
conditions with incoming showers.

Winds will be out of the south-southeast on Sunday but remain
light...around 10kts or less.


Memorial Day: VFR. Breezy. Likely SHRA.
Monday Night: VFR. Slight Chance SHRA.
Tuesday: VFR. Breezy. Chance SHRA...Slight Chance TSRA.
Tuesday Night: VFR. Chance SHRA.
Wednesday: VFR. Chance SHRA.
Wednesday Night: VFR. Chance SHRA.
Thursday: VFR. Chance SHRA.




NEAR TERM...Evenson/MV
SHORT TERM...Banacos
LONG TERM...Banacos
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