Area Forecast Discussion
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FXUS61 KBTV 281144
Area Forecast Discussion
National Weather Service Burlington VT
744 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 735 AM EDT Thursday...Mild conditions prevail across the
North Country early this morning with dewpoints in the low-mid 60s
and temperatures rising through the upper 60s and lower 70s at
1130Z. Surface analysis shows a weak frontal boundary across srn
Quebec into southeastern Ontario. Winds are nearly calm south of
the boundary...and light NW-N poleward 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 yesterday across the upr MS river valley and Great
Lakes region. These mid-level clouds will be in place much of the
day resulting in filtered sunshine.
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. Forcing aloft is not great...with limited height falls
and only brief period in LFQ of upper jet during early afternoon.
Low-mid tropospheric 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 around 1000 J/kg and PW
values of 1.5 to 1.6" this aftn. Bulk of the day will be dry in
most locations, but will see some scattered convective cells
around during peak heating hrs per NCAR/10member WRF ensemble and
the 06Z BTV-4km WRF. While we can`t rule out a stronger
thunderstorm or two, combination of mid-level lapse rates only
around 6 C/km and very weak low- level flow should limit overall
robustness and organization of scattered showers and thunderstorms
this afternoon. Isold stronger cores could have some small hail or
gusty winds, but anticipate 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 settles swd. 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- mid 60s.
.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 /12Z Thursday THROUGH Monday/...
Through 12z Friday...Generally VFR with SCT-BKN070-100 much of
the day. Scattered shower and thunderstorm activity 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. Mainly carried VCSH in TAFs ATTM. 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.