Area Forecast Discussion
Issued by NWS Burlington, VT-- Highlight Changed Discussion --
-- Discussion containing changed information from previous version are highlighted. --
FXUS61 KBTV 281948
Area Forecast Discussion
National Weather Service Burlington VT
348 PM EDT SAT MAY 28 2016
-- Changed Discussion --The Memorial Day weekend will continue to see well above normal
temperatures with daytime max temps between 10 to 20 degrees
above normal. Increasing low level moisture will allow for higher
relative humidities and an increasing chance for widespread
showers with scattered thunderstorms possible on Sunday and
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.NEAR TERM /THROUGH SUNDAY/...
-- Changed Discussion --As of 344 PM EDT Saturday...
With the 2pm observation in Burlington we reached 90 degrees for
the second day in a row putting us two thirds of a way to a local
heat wave. Expect warm and muggy (relative to normal for the North
Country) conditions through the rest of the afternoon and early
evening. The scattered cumulus field has continued to develop
across both northern New York and Vermont, however the lack of
any significant forcing has prevented any showers from developing
as of this discussion. The lake breeze on the western edge of Lake
Champlain may end up being the trigger for some late afternoon
early evening convection depending on how inland it moves.
Additionally, the western edge of the Champlain Valley has been
considerable cooler with light to moderate onshore flow from the
much colder lake water temps. With the area somewhat unstable
150-200 J/kg of MUCAPE any showers that do develop will have the
potential to cause an isolated lightning strike or two.
As the upper level ridge continues to build this evening expect
another evening with some potential for patchy fog development. The
best chance will be over northern New York where we are still
drying out from the light rain that fell overnight Thursday.
Across Vermont where we`ve gone with consecutive drys days we may
not have enough boundary layer moisture to see widespread fog.
Tomorrow, as mentioned by the midnight crew, becomes quite the
active period. The upper level ridge overnight gives way to an
advancing upper level trough. There will be a large influx of
precipitable water with values rising to 1.6-1.8 by location.
925mb temps are elevated again Sunday and the 21-23C 925mb temps
will support max temps tomorrow once again in the upper 80s to low
90s. Currently the forecast for Burlington reaches heat wave
criteria with a max temps of 90 expected. Unlike today however
there will be a few piece of shortwave energy the ride along the
longwave trough providing the necessary trigger for convection to
occur. So I`ve continue to offer high chance to likely pops for
most of the forecast area. MUCAPE values are expected to exceed
500-1000 J/kg and K-index values also are indicated of
thunderstormdevelopment. With the chance for thunderstorm
development, slow storm motions, and abnormally high pwat, I
continued to mention the chance for heavy rain in any
thunderstorms that develop. We should be safe with regards to
flash flooding due to how dry we`ve been in May but caution should
be taken with any shower producing heavy rainfall.
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.SHORT TERM /SUNDAY NIGHT THROUGH MONDAY/...
As of 333 AM EDT Saturday...Most active period then takes shape
by later Sunday into Sunday night with the approach of a longwave
trough and its interaction with deep tropospheric moisture. The
first half of the day should be more of the same with partly
sunny, warm and modestly humid conditions with widely scattered
terrain-driven showers/isolated storms. A few record high
temperatures may again be threatened (see climate section at
bottom). As mid level heights begin to fall by later in the day
and toward evening expect a broader coverage of showers/storms to
develop and continue into Sunday night as upper trough approaches.
Anomalously high pwats in excess of 1.5 to 2.0 inches combined
with a deep moist-neutral airmass to near 30 kft all spell at
least the potential of locally heavy rainfall across the area,
especially from the Adirondacks eastward where some interaction
with the moisture plume from TD #2 may occur Sunday night. Will
thus introduce this idea along with other surrounding NWS offices
per intra-site coordination this morning. While antecedent dry
conditions should preclude a widespread flood threat, localized
hydrological concerns will be a possibility during this period. As
we progress into Monday the upper trough pulls east with a drier,
more stable airmass filtering into the region over time and
precipitation chances lowering accordingly. In regard to
temperatures I leaned close to blended MOS-based and bias-
corrected data offering highs on Sunday in the 80s to locally near
90F in the Champlain/St Lawrence Valleys, then somewhat cooler
from the upper 70s to lower 80s by Monday with more tolerable
humidity levels. Overnight lows Sunday night mainly in the 58 to
.LONG TERM /MONDAY NIGHT THROUGH SATURDAY/...
As of 333 AM EDT Saturday...The period from Monday night onward
through Thursday of next week will be dominated by surface high
pressure with generally fair weather, light winds and tolerable
humidity levels. Temperatures will remain several degrees above
normal, continuing the present trend that`s been established over
the past week or so. Highs should mainly range from the mid 70s to
lower 80s each afternoon with overnight lows generally in the 50s
to around 60.
By late week, a slightly more vigorous northern stream trough and
attendant surface front will make a run into the northeastern third
of the nation. As this feature approaches expect a renewed threat of
showers from Friday into next Saturday.
.AVIATION /20Z Saturday THROUGH Thursday/...
Through 12z Sunday...Generally VFR conditions through the TAF
period...with SCT mid-upper level clouds. Light fair weather
cumulus has begun to pop up over the adirondacks with an isolated
showers or thunderstorm possible. Areal coverage is minimal so
I`ve only included vcsh for PBG which has the best chance to see a
shower in the vicinity this afternoon. Generally calm to light
and variable winds will continue this afternoon before going calm
overnight and then southerly tomorrow morning.
Outlook 12z Sunday through Wednesday... Mainly VFR with a daily
chances for showers and thunderstorms each afternoon and evening.
Greatest coverage/threat appears to occur in the Sunday and Monday
time frame. Best chance for a dry day will be Wednesday.
Record maximum temperatures for Saturday 5/28 and Sunday 5/29 are as
BTV - Burlington 92 in 1978 89 in 1978
MPV - Montpelier 88 in 1978 87 in 1978
MSS - Massena 89 in 1978 90 in 1978
St Johnsbury 93 in 1978 92 in 1978
Mt Mansfield 77 in 1978 77 in 1978