Area Forecast Discussion
Issued by NWS Burlington, VT

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FXUS61 KBTV 221410

Area Forecast Discussion
National Weather Service Burlington VT
1010 AM EDT Thu Jun 22 2017

High pressure will build into the region through this afternoon
with dry and seasonably pleasant weather expected. Showers and
thunderstorms return to the region by overnight Thursday into
Friday morning with locally heavy rainfall possible. A brief
return to dry weather is expected on Saturday before more
showers return for the early portions of next week.


As of 1008 AM EDT Thursday...Only minor changes to previous
forecast for today. Can`t ask for a much nicer day than today,
minimal cloud cover, and very low precipitation chances. Feel
that best chance for showers remains Adirondacks and westward
and generally very late in the period this evening. Otherwise
lots of sun, low dewpoints and warm temperatures.

Previous discussion...High pressure will continue to build into
the North Country today. Mostly clear skies should continue
through the morning and we`ve been fortunate that the boundary
layer winds have stayed elevated enough to not see much in the
way of fog development although its not that far away as the
GOES-R Fog product shows fog creeping into the river valleys of
central NY and across portions of Quebec. The lone exception to
that is Saranac Lake were literally as I typed the previous
sentence the visibility started to fall due to ground fog

The daylight hours should be quite pleasant across the North
Country under mostly clear skies through the morning. Mid to
high level clouds will begin to build in from the west as a warm
front lifts to the north. The warm air will advecting in but
shouldn`t have a significant impact on max temps as 925mb temps
will only warm to 17-19C supporting highs in the upper 70s.

In the overnight hours, the PWATs surge to 1.7-2.0 inches and
moisture convergence increase at the surface leading to rather
healthy rain showers developing. The best chance for the showers
is generally over norther New York where some areas will see up
to an inch of rain overnight. With the warm air advection
continuing expect lows to trend warmer in the upper 50s to low
60s under south/southwesterly flow and increasing clouds.


As of 430 AM EDT Thursday...Warm air advection well underway by
Friday morning with warm frontal rainfall predominantly across
northern half of the forecast area. Surface and upper ridge will
be to the east, and our area will be opened up to subtropical
moisture streaming in from the gulf. Actual remnants of TS Cindy
will move east across the mid-Atlantic coast, but we`ll get a
good sample of gulf moisture, and 850 and 700 mb theta-e ridge
surges into the area by mid day Friday. Model soundings in
BUFKIT indicate better warm rain processes in the morning, then
some mid level drying in the afternoon. Convective heavy
rainfall rates still a threat during the day Friday however
driven by precipitable water remaining near 2 inches. Examining
severe weather threat...not seeing really strong signals there.
NAM model CAPE over 2000 j/kg in the northern Champlain Valley
Friday afternoon, however with cloud cover limiting afternoon
heating I`m not convinced all that instability will be realized.
Additionally shear does not align well with max heating, with
one area of higher shear lifting north of the Canadian border
Friday morning, then higher shear again along the surface front
late in the day Friday after peak heating. SPC has also backed
off on risk of severe Friday, with Marginal threat over the
forecast area. Based on all this will continue to highlight
heavy rainfall threat in the forecast, and downplay strong storm

Expect area of rainfall to be lifting north during the morning
followed by a relative lull, then afternoon convection with
heavy rainfall rates firing in max heating and ahead of the
approaching front. Scattered showers/thunderstorms to continue
into Friday night with passage of the surface front. Boundary to
reach St. Lawrence Valley around 06z Saturday, Champlain valley
09z, and across entire forecast area by 12z Sat.

Temps Friday in the upper 70s to low 80s. 850 & 925 mb temps
support mid 80s, but clouds and rain around should knock a few
degrees off the max potential. Most of Friday night will be with
high dewpoint air remaining in the area, with muggy mins in the

Cooler and drying trend on Saturday with westerly flow at the
low levels backing southwest aloft ahead of the next 500 mb
trough settling into the Great Lakes region. Lingering showers
in the northern higher terrain supported by differential heating
and upslope flow. High temps Saturday in the 70s.


As of 430 AM EDT Thursday...SHRA/TSRA activity with heavy
rainfall risk continues for the early part of Friday night
before organized activity moves east early Saturday.

Broad upper level trof remains over the Great Lakes and
northeast into the middle part of next week. Can`t really find
any one period in the extended that will be completely dry with
cyclonic flow aloft and weak shortwaves rotating around the base
of the trof. SHRA chances will continue in the forecast through
the period.


Through 12Z Friday...VFR conditions expected through this
afternoon as skies will be mostly clear under high pressure.
Clouds will begin building into the north country this afternoon
as a warm front will bring rain showers to the northern taf
sites shortly after 00z Friday. Choose to offer VCSH for all
sites with prevailing -SHRA between 01-03z for BTV/PBG/MSS/SLK.
Winds light WSW turn more SW tomorrow.


Friday: VFR/MVFR. Breezy. Likely SHRA...Likely TSRA.
Friday Night: VFR. Numerous SHRA...Isolated TSRA.
Saturday: VFR. Breezy. Isolated SHRA.
Saturday Night: VFR. Slight Chance SHRA.
Sunday: VFR. Likely SHRA.
Sunday Night: VFR. Chance SHRA...Slight Chance TSRA.
Monday: VFR. Chance SHRA...Slight Chance TSRA.




NEAR TERM...Manning/Deal
LONG TERM...Hanson
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