FXUS61 KBTV 201417
Area Forecast Discussion
National Weather Service Burlington VT
1017 AM EDT Wed Jun 20 2018
A cold front dropping southward out of Canada will bring a chance of
showers to northern areas this evening through midnight, with high
pressure returning for Thursday and Friday. Unsettled conditions are
expected for the weekend with periods of rain likely, along with the
chance for a few rumbles of thunder.
.NEAR TERM /THROUGH THURSDAY/...
As of 1015 AM EDT Wednesday...Forecast remains in good shape
overall and just updated current temp/dewpoint trends to account
for observed RH values across the North Country. Expect
temperatures to warm into the mid 70s to lower 80s this
afternoon as RH values drop to 25 to 35 percent.
Previous Forecast...Main weather feature of interest for the
next 36 hours will be a cold front dropping southward from
Canada this evening through the overnight hours. Ahead of the
front, mostly sunny and dry conditions are expected for today
with temperatures about 5-10 degrees warmer than yesterday in
the mid 70s to low 80s. Cold front approaches the international
border around sunset with the latest 00Z CAM models indicating a
little more instability and forcing compared to previous runs
so have bumped up PoPs into the 30-50% range across northern
areas through midnight. Instability is only on order of a couple
hundred J/kg of CAPE through about 02Z so included just a
slight chance of thunder along the border through that time.
Otherwise, convective activity fizzles as it moves south after
sunset so central and southern areas will likely remain dry.
There will be a marked increase in sky cover with the frontal
passage which will help to keep overnight temps milder than the
previous night in the mid 40s to mid 50s.
For Thursday, high pressure returns behind the departing front
with northerly flow in the low/mid levels keeping temps on the
cool side back in the upper 60s to low 70s despite full
.SHORT TERM /THURSDAY NIGHT THROUGH FRIDAY NIGHT/...
As of 333 AM EDT Wednesday...The Thursday night thru Friday
night period will feature generally tranquil weather as sfc high
pressure builds from sern Ontario/swrn Quebec esewd across
northern New England, and eventually into the Canadian Maritimes
by Friday aftn into Friday night. Should see good radiational
cooling conditions with light winds and clear skies Thursday
night. Lows generally mid-upr 40s, but would anticipate some upr
30s in the normally colder locations within the nrn Adirondack
region and across sheltered locations of far nern VT. Should see
a moderating air mass on Friday as south winds develop around
10 mph. Relatively low humidity levels (2-m dewpoints in the upr
40s to lower 50s) will continue, but high temperatures will be
warmer on Friday, reaching the upr 70s to lower 80s. Will begin
to see some fringe effects of closed 700-500mb low expected
across the Ohio Valley Friday night. As this system slowly
shifts newd, increasing cloudiness is expected Friday night. The
00Z ECMWF suggests associated precipitation remains south and
west of our region Friday night, but the 00Z GFS is a bit
quicker to bring potential rain showers into nrn NY after
midnight. At this point, indicated just 20-30 PoPs for Franklin
NY and St. Lawrence counties during the pre-dawn period
Saturday. The increasing cloud cover will result in milder
overnight temperatures, with pre-dawn lows mainly in the 50s,
except near 60F for the St. Lawrence Valley.
.LONG TERM /SATURDAY THROUGH TUESDAY/...
As of 333 AM EDT Wednesday...Both the 00Z ECMWF/GFS suggest
unsettled weather this weekend as mid- level low over the Ohio
Valley is forecast to become an open wave and lift newd across
NY state on Saturday, and eventually across nrn New England for
Saturday night. A second mid-level trough in nwly flow moves
across the North Country late Sunday into early Monday, with the
potential for additional scattered showers. Precipitable water
values will be moderately high but not excessive. Unlike the 2"+
PW experienced this past Monday, will see values 1.5-1.7" in
advance of the Ohio Valley system for Saturday. Overall, present
indications suggest cloudiness and weak mid-level lapse rates
will keep instability low (SBCAPE < 1000 j/kg). Anticipate
widespread showers Saturday, and included a chance of embedded
thunderstorms west of the Green Mtns, including the Champlain
Valley and all of nrn NY (slight chance tstm east of the Green
Mtns). Severe storms not currently expected. Highs on Saturday
mainly in the 70s. Maintained 60-80 PoPs for Saturday night with
lows in the upr 50s to lower 60s. May see a break in the shower
activity on Sunday - especially during the morning hrs - but
with trailing shortwave trough approaching from sern Ontario,
should see another period of widespread showers late Sunday into
Sunday night/early Monday. Gradual clearing is anticipated
Monday night into Tuesday. Highs on Monday only in the lower
70s, but increased prospects for sunshine should result in highs
in the 75-80F range for valley locations on Tuesday.
.AVIATION /14Z WEDNESDAY THROUGH SUNDAY/...
Through 12Z Thursday...Lingering IFR fog at KMPV and KSLK
will lift within the hour with conditions largely VFR through
the period. Scattered cirrus and perhaps a few fair weather
cumulus will stream across the region through the day before a
low/mid level deck increases from the north from late afternoon
onward as a cold front approaches. Could see a few showers
along the international border to the Adirondacks and central
Vermont from sunset through midnight, with brief reductions in
vsby possible. Any shower activity wanes after midnight with a
slow clearing occurring from north to south towards sunrise.
Thursday: VFR. NO SIG WX.
Thursday Night: VFR. NO SIG WX.
Friday: VFR. NO SIG WX.
Friday Night: VFR. Slight chance SHRA.
Saturday: VFR. Likely SHRA, Chance TSRA.
Saturday Night: MVFR/IFR conditions possible. Likely SHRA.
Sunday: Mainly MVFR, with areas IFR possible. Likely SHRA.