261
FXUS61 KBTV 232329
AFDBTV

Area Forecast Discussion
National Weather Service Burlington VT
729 PM EDT Mon Apr 23 2018

.SYNOPSIS...
High pressure will continue to provide ideal spring weather to
the region with fair skies and seasonably mild temperatures
expected through Tuesday. Low pressure lifting out of the Ohio
Valley and Mid Atlantic States will bring the next round of
showers and a period of steadier rainfall on Wednesday into
Thursday.

&&

.NEAR TERM /THROUGH TUESDAY NIGHT/...
As of 725 PM EDT Monday...No changes were needed with this
update. Skies remain clear, winds light, and temperatures are in
the 60s areawide. Enjoy your evening!

Previous discussion...Just an outstanding day unfolding today
as deep layer high pressure remains bridged across the
northeastern quarter of the nation. Deep layer mixing and full
sun has allowed temperatures to climb into the 60s in many
locations which has helped erase sore memories of our cold
stretch and snow of late late winter/early spring for many. With
the ridge in place a persistence forecast will be offered with
just some passing high clouds and quiet weather expected through
tomorrow. Similar to last night, forecast lows tonight were
heavily governed by blended MOS output showing inherent
variability during light wind/clear sky nocturnal regimes. In
general, values should fall into the upper 20s to mid 30s in the
mountains, and from the mid 30s to lower 40s in the St.
Lawrence and Champlain Valleys where light south/southwest winds
around 5 mph will likely keep the near-surface layer mixed.
Highs on Tuesday to be the warmest of the work week - mainly 60s
to locally around 70 in mildest locales under light to modest
south/southwest return flow as mean 925-850 mb thermal profiles
warm by about 2 degrees.

By tomorrow night changes will be in the air as southern stream
energy across the Tennessee/Lower Ohio Valley lifts northeast and
merges with a digging northern stream upper trough approaching from
the west. The idea of thickening clouds along with showers/light
rain arriving from the south and west later at night or toward
morning still looks on track and given consistency in this
morning`s model output I`ve largely kept close to our prior
forecast in this regard. Lows to remain milder than past nights
with continued light south flow and clouds - mainly 40s with a
few upper 30s in coldest northern mountain hollows.

&&

.SHORT TERM /WEDNESDAY THROUGH THURSDAY/...
As of 326 PM EDT Monday...Wednesday will bring a return of
slightly more active weather to the forecast area as a more
dynamic pattern replaces the ridging over New England. Energy
associated with a shearing northern stream shortwave will dig
into the Great Lakes Region Wednesday morning, supporting
synoptic scale ascent ahead over the northeastern US ahead of
the vort max. At the same time, a cutoff low over the
southeastern US will gradually lift northeastward to the Mid-
Atlantic Coast Wednesday. Low level southeasterly flow ahead of
this cyclone will result in decent Atlantic-moisture advection
that will feed into the better dynamics moving in from the west.
The individual features will linger over the Northeast through
Thursday, then phase and quickly exit to the northeast as a jet
carries the strengthening low to the Canadian Maritimes Thursday
night. The net result of this setup will be a rainy Wednesday
through Thursday afternoon, with showers lingering in higher
elevations through Thursday evening. All said and done, it
looks like most areas will pick up between a half inch to nine
tenths of an inch of rain during this time period. Higher
terrain will generally see the most QPF, while the Champlain
Valley and Connecticut Valley will see QPF values on the lower
end of this spectrum.

Daytime high temperatures Wednesday and Thursday will top out
in the low to mid 50s, while overnight lows Wednesday night will
be moderated by the overcast skies, dropping only into the 40s
in most locations.

&&

.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
As of 326 PM EDT Monday...By Thursday evening, the widespread rain
will have ended, with only some lingering showers remaining in
higher elevations. Friday will be a nice break in between
systems as the now-phased shortwave quickly exits to the
northeast and some weak ridging tries to build in. We should get
some decent warm air advection Friday as southwesterly flow
increases during the day ahead of an upstream digging trough.
925 mb temperatures will climb to 10 to 15 degrees C during the
day, and sunny skies will rapidly warm surface temperatures to
the mid to upper 60s. Enjoy it while you can however, as clouds
will build Friday evening through Friday night ahead of the
next disturbance. The weekend will feature a setup similar to
the earlier midweek system, with a southern stream upper
wave/weak surface low interacting with a more potent northern
stream shortwave over the Mid-Atlantic/northeastern US region.
The timing/degree of phasing of the systems remains yet to be
determined, which could have implications on the more precise
timing/location of precipitation. Of higher certainty however is
that broad cyclonic flow will exist over the northeastern US
Saturday, regardless of whether or not the systems phase,
resulting in a fairly wet beginning to the weekend.

The good news however, is that the coldest air that has
loitered over the northeast for most of the first half of April
will be dislodged well to our north over northeastern Canada
for the long term, resulting in no foreseeable temperature
plunges to finish out the month. Our average highs/lows for this
time of year are in the upper 50s/upper 30s, and the longterm
pattern suggests that we`ll remain fairly close to climatology
through the weekend. Friday will be the warmest day in the
longterm, with high temps in the 60s, followed by a slight cool
down with highs in the 50s over the weekend. The longwave
pattern going into the following week is showing signs of a
building Bermuda High to our south, which would provide a warm
start to May for us if the pattern pans out. Safe to say spring
is here to stay.

&&

.AVIATION /00Z TUESDAY THROUGH SATURDAY/...
Through 00Z Wednesday...VFR conditions will persist through the
next 24 hours with just some passing scattered high cirrus
AOA 20,000 ft. Light winds overnight will trend south to
southwesterly from 6 to 12 knots with occasional gusts to 20 kts
possible at KBTV/KSLK/KMSS after 13z Tuesday. Only real concern
is some occasional southwesterly LLWS to 35kt at KMSS terminal
in the 06-12Z time frame as stronger flow aloft pushes into the
region.

Outlook...

Tuesday Night: VFR. Likely RA, Chance SHRA.
Wednesday: Mainly MVFR, with local IFR possible. Definite RA.
Wednesday Night: MVFR. Likely RA.
Thursday: Mainly MVFR, with local IFR possible. Likely SHRA.
Thursday Night: Mainly VFR, with local MVFR possible. Chance
SHRA.
Friday: VFR. Slight chance SHRA.
Friday Night: Mainly VFR, with local MVFR possible. Chance SHRA.
Saturday: Mainly VFR, with local MVFR possible. Chance SHRA.

&&

.BTV WATCHES/WARNINGS/ADVISORIES...
VT...None.
NY...None.

&&

$$
SYNOPSIS...JMG
NEAR TERM...Hastings/JMG
SHORT TERM...RSD
LONG TERM...RSD
AVIATION...Hastings/JMG