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fxus61 kbtv 251311 

Area forecast discussion
National Weather Service Burlington Vermont
911 am EDT Tue Apr 25 2017

clouds and moisture from a low pressure area along the mid
Atlantic coast will move north into the region today, with rain
showers developing across the north country this afternoon
and tonight. Rain showers will continue tonight and into
Wednesday. Expecting partly to mostly cloudy skies Wednesday
night. Thursday will see warmer temperatures with highs in the
70s under partly sunny skies.


Near term /until 6 am Wednesday morning/...
as of 905 am EDT Tuesday...quick update based on satellite,
radar and surface observation trends. Band of rain, most of it
on the light side, is pushing northward at a steady pace and on
the doorstep of Rutland and Windsor counties. Hrrr has a pretty
good handle on the current situation, with some of the other hi-
res models not too different as well, so relied on that for
updating the precipitation movement the next 12 hours or so.
Looking at a steady progression northward, with the rain
reaching the US/Canada border early this afternoon. With a
relatively dry airmass in place, the rain won't be heavy,
looking at mainly rainfall totals <0.15" or so. Expecting less
across the Champlain Valley as strengthening southeast winds
will lead to downslope shadowing and lesser amounts. However,
some enhancement is expected on the eastern slopes of the
central/southern greens, so local totals around 1/4" are

Those southeast winds do strengthen as the day GOES on, with the
NAM indicating about 40kts between 925mb-850mb (roughly
2000-4500ft). As a result, we should see some gusty downslope
winds develop along the immediate western slopes of the Green
Mountains. However, the expected rainfall should keep the lowest
part of the boundary layer stabilized enough that the strongest
of winds won't make it to the surface. Still looking at probably
gusts on the order of 25-35 mph.

Models do show a break in the precipitation late today/this
evening, with a another round of deeper moisture moving in
overnight. Noted that showalter values decrease associated with
some instability aloft at that time, so expecting the character
of the precipitation to turn more showery overnight.


Short term /6 am Wednesday morning through Wednesday night/...
as of 418 am EDT Tuesday...expecting rain showers to continue
into Wednesday morning as the closed upper low and the surface
low will be coincident with each other south of Long Island New
York Wednesday morning. This low will then move east and be over
Cape Cod Wednesday night. Expecting the north country to be
partly to mostly cloudy Wednesday night, but remaining dry.
Models showing upper ridge to build into the region by late
Wednesday night.


Long term /Thursday through Monday/...
as of 420 am EDT Tuesday...not much change in the forecast but
overall active period during the long term. The period will
start off dry as rain showers associated with coastal low
continue to move east. Some lingering clouds may limit warming
over eastern Vermont, but generally expect temperatures in the

Thursday night into Friday will have chance for showers and
possible thunderstorms that are expected to move west to east
across the north country as a long wave 500mb trough becomes
negatively titled over Ontario, extending into the eastern Great
Lakes. Reflected at the surface, a front boundary will provide
the lift for these showers...clearing the area by Friday night.

Heading into the weekend, a Bermuda high looks to develop at
the surface and aloft. Several areas of vorticity at 500mb will
move from SW towards southern Quebec and possibly impact the
north country through Saturday night.

On Sunday, Canadian high pressure centered around James Bay
will retreat north and east as strengthening closed surface low
moves northward from Texas towards the western Great Lakes by
late Sunday. A warm front ahead of the low looks to bring more
showers by Sunday night. GFS and European model (ecmwf) still show differences on
evolution and track of this system, but strong low level jet
associated with cold front will create good moisture plume from
the Gulf of Mexico northward. Expect this cold front to move
into the north country sometime Monday. Overall expect this
system to be capable of producing heavy rainfall and strong
winds from tight pressure gradient and strengthening of low.
Also, thunderstorm activity expected ahead and along the cold
front as GFS indicates 500-1000 j/kg in the St Lawrence Valley
and negative lifted indices.


Aviation /13z Tuesday through Saturday/...
through 12z Wednesday...mainly VFR conditions expected through
00z Wednesday. Satellite loop and surface observations showing
mainly high and mid clouds across the region at this time.
Expecting ceilings to slowly lower through the day. BUFKIT
forecast soundings showing fairly dry conditions across the
region, so it will likely take a while to saturate the lower
levels of the atmosphere. Expecting any rain shower activity
will likely not reach the surface until this afternoon or this
evening. Expecting mainly MVFR conditions in rain showers after
00z Wednesday.


Wednesday: VFR/MVFR. Chance rain showers.
Wednesday night: VFR. Slight chance rain showers.
Thursday: VFR. No sig weather.
Thursday night: VFR. Slight chance rain showers...tsra.
Friday: VFR. Chance rain showers...tsra.
Friday night: VFR. Chance rain showers.
Saturday: VFR. Chance rain showers.


Btv watches/warnings/advisories...
New York...none.



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