Area Forecast Discussion
Issued by NWS Burlington, VT

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000
FXUS61 KBTV 220917
AFDBTV

Area Forecast Discussion
National Weather Service Burlington VT
417 AM EST Wed Feb 22 2017

.SYNOPSIS...
Much above normal temperatures continue into the weekend with
scattered showers and areas of fog possible...especially tonight
into Thursday. A strong cold front will produce gusty winds and a
line of showers on Saturday afternoon and evening...with much cooler
temperatures by Sunday. The combination of snow melt and
precipitation will result in localized ice jam threat with the
potential for isolated low lying flooding as we head into the
weekend.

&&

.NEAR TERM /THROUGH THURSDAY/...
As of 401 AM EST Wednesday...Fast westerly flow aloft continues
today...while low level winds are from the south/southwest
resulting in moisture and warm air advection. Have noted plenty
of low clouds and fog upstream associated with higher moisture
content and warm air moving over cold snow pack...especially MI.
Soundings indicating the threat for fog/br increases by
tonight...especially deeper/protected mountain valleys and this
trend may continue into Thursday. Progged 850mb temps warm
between 2-4c today...but with all the clouds mixing maybe
limited...so will keep temps mid 40s to lower 50s most
locations. An isolated shower cannot be ruled out over the
terrain...but any precip will be light.

Tonight...the potential for fog/br increases as temps cool back into
the 30s and lower 40s...but surface dewpoints continue to increase
on southerly winds. Will continue to mention patchy to areas of
fog/br...given sounding profiles...with mostly likely locations the
SLV/northern Dacks and parts of central/northern VT valleys.

Thursday...temps become very tricky as we continue to be under
moderate low level warm air advection on gusty south/southwest
winds. However...these winds continue to advect higher moisture into
our region with surface dwpts in the upper 30s to mid
40s...supporting areas of low clouds and fog...which may limit
surface heating. Area soundings show lots of moisture between
surface and 850mb on Thursday...associated with strong moisture
advection on 925mb to 850mb winds of 35 to 45 knots. Soundings
support localized wind gusts btwn 30 and 35 knots in the
SLV...dacks and parts of the CPV on Thursday afternoon. Areas of
drizzle will be possible in the mountains on Thursday. For temps
will fall high resolution 2m temps...which support mid 40s mountain
valleys to l/m 50s warmer valley locations. A weak surface boundary
along with increasing mid level moisture will increase the threat
for showers on Thursday afternoon...as pws surge between 0.75 and
0.95. Have mention chance to low likely pops...but best forcing
associated with 5h vort and better moisture looks to pass just to
our north. QPF will be <0.10.

&&

.SHORT TERM /THURSDAY NIGHT THROUGH FRIDAY NIGHT/...
As of 412 AM EST Wednesday...Friday brings with it an increase
in clouds and precipitation as a passing upper ridge gives way
to an upper through and a warm front from an associated rapidly
developing low over the midwest US late in the day. Light
precipitation should move throughout the later part of the day
through the region, although QPF looks to only be about .10 on
average for most locations. Slightly cooler temps are expected
for Friday as increased cloud cover along with the late
influence of the advancing warm front will see daytime highs in
the mid 40`s while temps should continue to rise in central and
western parts of the CWA while the eastern portion should see
some cooling overnight, leading to overnight lows ranging in the
mid 40`s to upper 30`s.

&&

.LONG TERM /SATURDAY THROUGH TUESDAY/...
As of 412 AM EST Wednesday...Saturday afternoon/evening should
see the precipitation ramping up just ahead of the passage of a
cold front from the associated occulded system pushing to the
north and west of our area. Most of the CWA should see a half
to three quarters on an inch of precipitation during this
timeframe. Winds out ahead of the front could lead to a narrow
band of gusty conditions and advisory level winds especially
across the Champlain and St Lawrence Valleys as the 00Z GFS
continues to indicate 850mb winds reaching 65 and 70 knots in
the respective valleys Saturday afternoon. After frontal
passage, rain will switch over to snow showers late Saturday
night/Sunday morning with moderate cold air advection. Very warm
temperatures are expected Saturday ahead of the cold frontal
passage. Temperatures overall look to be in the mid to upper 50s
with the Champlain and St Lawrence Valleys pushing a record
breaking 60. The sharp cold front will drop temps quickly back
into the upper 20s and lower 30`s late Saturday night. Flash
freeze issues are possible in some locations with temperatures
dropping so sharply after a moderate rainfall. Next week see a
return to more seasonable and quiet weather Sunday through
Tuesday before another system moves in at the end of the period
on Wednesday.

&&

.AVIATION /09Z Wednesday THROUGH Sunday/...
Through 06z Thursday...VFR conditions continue as the weak
shortwave trough pushes across the area. Light drizzle may
continue over the next couple of hours by dry low levels will
prevent any significant precip from reaching the ground. The
models have been consistent with the potential for some MVFR
clouds through the morning hours however the source region for
our airmass doesn`t support this so I`ve opted to hover right on
the border with clouds in the 3000-4000ft elevation. Winds will
continue to be generally south to southwesterly with gusty
winds possible at BTV only due to funneling of the Champlain
Valley. Tomorrow evening with warm dew points and moisture
available from the melting snowpack the potential will exist for
some light ground fog to develop. Winds and cloud cover will be
the limiting factor in how much fog develops and thus visibility
restrictions.

Outlook 06z Wednesday through Sunday...
Thursday...VFR/MVFR with pockets of MVFR/IFR in our mountains
sites.

Friday - Saturday...A warm front lifting from southwest to
northeast on Friday will produce additional showers along with
some enhanced southerly winds. The turning wind profiles and
rapid increase in speed with height will cause some areas of
turbulence and shear on Friday Night into Saturday. Widespread
gusty southerly winds likely on Saturday with areas of rain
showers...producing localized mvfr/ifr cigs/vis in the heavier
elements.

Sunday...VFR/MVFR conditions possible, especially in mountains
snow showers.

&&

.HYDROLOGY...
As of 400 aM EST Wednesday...Above normal temperatures will
continue to melt a significant amount of snow this week into the
upcoming weekend. This runoff will cause rises on local
waterways with an increasing threat for localized ice jam
flooding...especially across northern NY and central and
northern VT rivers. A widespread rainfall on Saturday will
produce additional hydro concerns over the weekend for the
potential of minor main stem river flooding.

&&

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

&&

$$
SYNOPSIS...Taber
NEAR TERM...Taber
SHORT TERM...MV
LONG TERM...MV
AVIATION...Deal/KGM
HYDROLOGY...Taber



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