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FXUS61 KBTV 280746
Area Forecast Discussion
National Weather Service Burlington VT
346 AM EDT Thu Jul 28 2016
A frontal boundary just north of the international border early
this morning will settle slowly southward across the North Country
today. Meanwhile, an upper level disturbance across the central
Great Lakes will move eastward, and result in scattered showers
and thunderstorm activity near the frontal zone this afternoon and
evening. High temperatures will generally reach the mid to upper
80s across the region today. A few showers are possible again on
Friday, mainly across south- central Vermont as the low-level frontal
zone continues to shift southward into southern New England.
Cooler and drier air will filter in across northern sections, with
highs in the lower 80s for Friday and upper 70s to lower 80s for
Saturday, with lower humidity levels.
.NEAR TERM /THROUGH TONIGHT/...
As of 341 AM EDT Thursday...Mild conditions prevail across the
North Country early this morning with dewpoints in the low-mid 60s
and temperatures ranging from the mid 60s most sections, to the
lower 70s across the St. Lawrence and Champlain Valleys. Surface
analysis shows a weak frontal boundary across srn Quebec into
southeastern Ontario. Winds are nearly calm south of the
boundary...and light W-NW north of the trough line with dewpoints
mainly in the mid-upr 50s north of the front (an air mass that
will be in place across the North Country for Friday). Some mid-
upper level clouds are streaming ewd across the region this
morning, mainly a function of convective debris from thunderstorms
earlier today across the upr MS river valley and Great Lakes
region. These mid-upr clouds are limiting radiational fog
formation, but can`t rule out patchy development 8-11Z in the
favored valleys of central/ern VT and within the valleys of the
Northern Adirondack region.
Remnant 500mb vort across the central Great Lakes will shear out
ewd in W-E belt of strengthening 300-200mb flow approaching
90-100kt across Lake Ontario ewd into nrn NY/VT by 18Z this
afternoon. That said, low-mid level flow will remain rather light
in vcnty of sfc trough/frontal zone, as it sags swd into nrn NY/VT
by early to mid afternoon. Insolational heating with filtered
sunshine will yield 2-m temps in the low-mid 80s, and with mid 60s
dewpoints in place, will contribute to SBCAPE values of 1000-1500
J/kg and PW values of 1.5 to 1.6" this aftn. Can`t rule out a
stronger thunderstorm or two, but combination of mid-level lapse
rates only around 6 C/km and very weak low-level flow should limit
overall robustness and organization of widely scattered convective
cells this afternoon. A few stronger cores could have some small
hail or gusty winds, but generally below svr limits. PoPs peak
around 60-70 Percent 18-20Z across central/nrn VT, and generally
40-50 percent across s-central sections.
Into the early to late evening hours, will see convective coverage
and intensity gradually diminish and generally focus across
s-central VT as frontal zone sags south. Effective front may be
marked by convective outflows pushing swd through the evening
hours. Precipitation should be generally ending by 06z, with
patchy fog possible in favored valleys 06-12z, especially in areas
seeing daytime/evening thunderstorm activity and residual wet
ground conditions. Low temperatures tonight generally in the low-
.SHORT TERM /FRIDAY THROUGH SATURDAY/...
As of 341 AM EDT Thursday...Cluster of convection looks to affect
more of southern New England on Friday than northern areas. Would
expect a fairly sharp gradient of precipitation given the west to
southwest flow aloft. Areas near the Canadian border should remain
dry with a chance of showers across central and south central
Vermont. High temperatures on Friday will generally be in the
upper 70s to lower 80s. Any lingering precipitation comes to an
end Friday evening with high pressure starting to build down from
Canada late Friday night into Saturday. No precipitation is
expected during this period with highs on Saturday in the mid 70s
to lower 80s.
.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
As of 341 AM EDT Thursday...Trends in the data now suggest a
shortwave trough moves into the region on Sunday for a chance of
showers right through Sunday night. The pattern looks to change
for the first half of next week with an upper level ridge of high
pressure gradually building in for relatively dry weather and a
gradual warming trend with highs in the 80s all areas Tuesday and
.AVIATION /08Z Thursday THROUGH Monday/...
Through 12z Friday...Generally VFR with SCT-BKN070-100 much of
the day. Scattered shower and thunderstorm activity will become
most widespread 16-20Z, and then gradually diminish in coverage
during the evening hours, while generally shifting swd into srn
VT. Brief periods of MVFR/IFR possible in shower and thunderstorm
activity with brief heavy downpours. Winds generally light S-SW,
becoming light N-NW with weak frontal passage this afternoon...and
remaining light north tonight. Patchy fog possible during the
06-12Z Friday period, especially at locations seeing
shower/thunderstorm activity during the aftn/evening period with
residual wet ground conditions.
Outlook 12z Friday through Monday...Mainly VFR. Isold -SHRA
possible s-central VT/KRUT during Friday afternoon. Chance for
additional showers on Sunday, with isold -TSRA possible mainly
across srn sections.