Area Forecast Discussion
Issued by NWS Burlington, VT-- Remove Highlighting --
-- Discussion containing changed information from previous version are highlighted. --
FXUS61 KBTV 222327
Area Forecast Discussion
National Weather Service Burlington VT
727 PM EDT Sat Apr 22 2017
A mid-level trough over the North Country will exit eastward
tonight. A ridge of high pressure will build into the region on
Sunday and will remain over the region through Monday. Then a
coastal low pressure system will bring rain to portions of the
region Tuesday into Wednesday. Seasonable temperatures will see
a warm up for the latter half of next week.
.NEAR TERM /THROUGH SUNDAY/...
-- Changed Discussion --As of 720 PM EDT Saturday...Forecast remains on track. Will see
some competing influences overnight as strengthening inversion
850-800mb layer helps to trap stratus layer, while drier air
gradually works in from the NNW with 20-25kt winds at 900mb.
Anticipate a very gradual clearing overnight, starting with the
St. Lawrence Valley and eventually into the Champlain Valley
toward daybreak. Orographic upslope will maintain stratus
especially across the nrn Adirondacks and areas east of the
Green Mtns overnight. Can`t rule out some patchy fog after
midnight across nrn NY in areas that do clear out, and as PBL
stabilizes. Composite reflectivity still shows a few isold -RW
in cyclonic flow field, especially across wrn VT. Will maintain
15-30% PoPs thru about 06Z before trending completely dry. QPF
amts T" to a few hundreths, mainly across the mtns.
Skies will trend mostly sunny with light winds for Sunday,
setting up a pleasant day.
Temperatures tonight will be directly impacted by how
quickly/slowly clouds move out. Expect temperatures to be a few
degrees cooler over most of NY than VT as clearing reaches nrn
NY first. Generally expect mins in the upper 20s to mid 30s.
With more sunshine, max temperatures on Sunday expected to reach
the mid 50s to mid 60s.
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.SHORT TERM /SUNDAY NIGHT THROUGH MONDAY/...
As of 343 PM EDT Saturday...Surface ridge axis will slide off
the Atlantic coast as cold front associated with surface low
near Hudson`s Bay skims the international border. Expect North
Country to stay mainly dry, but see an increase in clouds
through Monday. Min temps Sunday night in the 30s. Due to the
increase in clouds, max temps Monday will be cooler in the upper
40s to mid 50s...coolest temperatures will be further north
under thicker clouds.
.LONG TERM /MONDAY NIGHT THROUGH SATURDAY/...
As of 307 PM EDT Saturday...An unsettled weather pattern anticipated
for days 4 thru 7 with chances for mainly light rain showers.
First round of light rainfall occurs Tuesday afternoon into
Tuesday Night...with main focus along and east of the CPV. This
precip is associated with developing east/southeast flow and
plume of deeper moisture with pws values approaching 1.0".
However...nose of 850mb jet remains to our east...along with
deepest moisture progs...so anticipating mainly light rain with
initial 5h vort and good upper level divergence from departing
rrq of 250mb jet over eastern Canada on Tuesday evening. Qpf
will range from <0.10 western cwa to 0.10 to 0.30 across the
favorable se upslope regions of the Green Mountains. A brief
break is anticipated late Tuesday Night...before more moisture
associated with closed 5h/7h and weak surface low pres along the
coast impacts our region by Weds. Latest GFS/ECMWF shows a
sharp west to east gradient in the 850 to 500mb moisture
fields...so anticipating heavier precip east and just clouds
over the slv on Weds. The combination of easterly upslope flow
at 25 to 35 knots between 925mb and 850mb and additional 5h
vorticity advection will produce another 0.10 to 0.25 across our
central/eastern sections on Weds. Clouds and precip will have
impact on temps with warmest values near 70f SLV and much cooler
with easterly flow and moisture across our eastern cwa with
highs upper 40s to lower 50s likely on Weds.
System is progged to lift ne of our cwa by Thursday with weak short
wave ridge building across the mid Atlantic/NE CONUS. This results
in strong low level waa on breezy south/southwest winds. Progged
850mb temps btwn 12-14c with 925mb temps 18 to 20c...support highs
well into the 70s with a few readings near 80f. Have trended toward
the ecmwf for a slower arrival of next system with the potential for
showers entering our western cwa by 18z Thursday and tracking east
toward evening. Thinking a slower departure of mid/upper level
cyclonic on Weds...will result in a slower arrival of next system
for Thursday...therefore have trimmed back superblend pops to chance
at this time. Depending upon fropa timing...surface heating could
produce some modest CAPE values between 200 and 600 j/kg to support
a rumble or two of thunder. Just a thought as we move forward.
Otherwise...a front is draped across our the region on Friday into
Saturday with cooler and unsettled weather prevailing.
.AVIATION /00Z SUNDAY THROUGH THURSDAY/...
Through 18Z Sunday...Champlain valley seeing VFR conditions
with MVFR at KMSS/KSLK and IFR at KMPV. Expect VFR to persist in
the Champlain Valley through Sunday evening.
Back edge of MVFR cigs is gradually shifting eastward and
expect KMSS to see breaks in overcast late this afternoon.
However, VFR not expected til after 00Z at KMSS.
MVFR cigs expected to persist at KSLK longer in generally
upslope flow. Brief break in MVFR cigs after 02Z will result in
potential for MVFR BR/FG development and MVFR cigs. Expect
conditions to improve to VFR after sunrise Sunday.
IFR at KMPV will improve to MVFR this afternoon and eventually
become VFR early Sunday morning. Scattered rain showers this
afternoon will diminish this evening.
Winds generally out of the W to NW at 5-10kts this afternoon
and evening. With high pressure building overnight, lgt and vrb
winds expected through late morning Sunday.
Sunday Night: VFR. NO SIG WX.
Monday: VFR. NO SIG WX.
Monday Night: VFR. NO SIG WX.
Tuesday: VFR/MVFR. Chance SHRA.
Tuesday Night: VFR/MVFR. Chance SHRA.
Wednesday: VFR. Chance SHRA.
Wednesday Night: VFR. Slight Chance SHRA.
Thursday: VFR/MVFR. Chance SHRA...TSRA.