FXUS61 KBTV 121719
Area Forecast Discussion
National Weather Service Burlington VT
119 PM EDT Thu Sep 12 2019
High pressure building southward from Ontario and Quebec will
provide increasing sunshine through today with a chance for a few
morning showers across southern Vermont. Clear skies and cool
conditions follow for tonight through Friday before showers return
for Friday night into Saturday, along with some gusty winds. A
chance for showers exists Sunday with the passage of a weak
disturbance aloft, then conditions trend warmer and drier for next
week as a large ridge of high pressure dominates.
.NEAR TERM /THROUGH FRIDAY/...
As of 1029 AM EDT Thursday...The band of light rain continues
to slowly slide to the south this morning as the upper level
trough begins to swing through the North Country. Additional
rainfall amounts should continue to be a tenth of an inch or
less with only a few hundreths being observed over the past few
hours. Models are a bit more pessimistic to how quickly the
clouds will begin to diminish this afternoon so we could see
clouds linger a little longer through the day. Nevertheless, by
sunset it looks like we should be in store for quickly clearing
skies with drier air quickly displacing any residual moisture.
Previous Discussion...Latest trend has been for the decaying
convective complex that was over the Great Lakes earlier in the
night to dive south of the forecast area while significantly
reducing in areal coverage. Models remain very insistent though that
there will be some sort of flare- up during the 12-16Z timeframe
across southern Vermont, so while I`ve trended the forecast drier
based on trends, still can`t rule out some showers this morning.
Overall though, the surface front lies further south of the forecast
are than previously forecast which support less chances for precip
today and higher chances for more sun. Morning clouds should
gradually clear from north to south through the day as high pressure
over Ontario/Quebec drifts into the Northeast. Temps across the
region will run several degrees below normal with northern areas
seeing mid/upper 60s, while southward low 60s are progged where
thicker cloudiness will prevail in the early afternoon.
Skies rapidly clear tonight as the high centers over Quebec with
abating winds setting up favorable conditions for fog development
along with the potential for some isolated frost as temperatures
fall into the 40s area-wide, and locally 30s in the hollows of the
Adirondacks and Northeast Kingdom. As the high shifts farther east
Friday, a light southerly wind will warm temps back to seasonal
values in the mid 60s to lower 70s with morning fog burning off and
just some increasing cirrus clouds expected for the afternoon.
.SHORT TERM /FRIDAY NIGHT THROUGH SATURDAY/...
As of 324 AM EDT Thursday...Highly advertised coupled low across
central Canada weakens and lifts ENE across Canada. The return flow
around departing surface high and approaching warm front from the
above mentioned low will allow a decent moisture transport of PWATS
around 1.5 inches in brisk 850mb SW flow >40kts ahead of front
arriving in St. Lawrence Vly ard/aft midnight and VT ard/aft
Despite the moisture transport...the lift is marginal as most/all
energy lifting well NW into Canada. Therefore more numerous showers
in Nrn NY Fri ngt/Sat mrng and more scattered in VT during Saturday.
It will be windy, esp St. Lawrence and Champlain Vlys with
850mb/925mb SSW jet of 40-50kts/35-40kts respectively gradually
diminishing during the day as cold/occluded front approaches/passes.
.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
As of 324 AM EDT Thursday...Front slowly passes Saturday night as
again the main push is ENE, parallel to orientation of the front and
surface high that was in control late Thursday-Friday just shifted a
bit offshore and rebuilds toward mid-Atlantic...never really exiting
the picture. Therefore...can`t rule out an isolated shower/two
Largely zonal flow for the rest of the period with some features
changing configuration at times. A northern stream shortwave late
Sunday-Sunday night will bring a minor threat of showers.
Thereafter...the southern US Heat ridge that has been baking that
area attempts to build into Northern Plains early week and then
slide east toward Great Lakes then slows/stalls as there is an
overall block in the steering currents. Early in the week, we stay
under the influence of a sharpening NNW flow with slowly building
heights and by midweek we start to touch the upper level ridge.
I mentioned several days ago about a potential backdoor front under
this sharp NNW flow and this holds true for Monday but how far west
is still in question. 925mb temps on Sunday are 15-18c across area,
potentially dropping to 10-15C Monday and then ranges anywhere from
9-16c on Tuesday before rebounding Wednesday. Will just have to
monitor closely to see how this plays out. Best, warmest in our
region will be St. Lawrence Vly and summer will not be too far south
and west of the region. It should be dry early next week.
Overall, it will be a milder week ahead but may have a brief speed
bump before that plays out by midweek.
.AVIATION /17Z THURSDAY THROUGH TUESDAY/...
Through 18Z Friday...With skies beginning to clear, the northern
terminals have picked up some 10 to 18 knot winds this afternoon
and this should continue until sunset when the surface begins to
stabilize. A few pockets of MVFR ceilings reside across the
North Country but the majority of the low clouds have exited off
the south. Skies will be trending toward SKC after unset with
drier air moving into the region. Fog still looks likely tonight
but will likely be delayed until around 09Z as winds aloft will
prevent the fog from settling at the surface initially. This fog
will lift between 12Z and 13Z with SKC conditions and south
winds 10 knots or less through Friday morning.
Friday Night: VFR. Chance SHRA.
Saturday: Mainly MVFR, with areas VFR possible. Chance SHRA.
Saturday Night: Mainly VFR, with areas MVFR possible. Chance
Sunday: Mainly VFR, with local MVFR possible. Slight chance SHRA.
Sunday Night: Mainly VFR, with local MVFR possible. Slight chance
Monday: Mainly VFR, with areas MVFR possible. Slight chance SHRA.
Monday Night: VFR. NO SIG WX.
Tuesday: VFR. NO SIG WX.