Area Forecast Discussion
Issued by NWS Burlington, VT-- Highlight Changed Discussion --
-- Discussion containing changed information from previous version are highlighted. --
FXUS61 KBTV 220850
Area Forecast Discussion
National Weather Service Burlington VT
350 AM EST Sun Jan 22 2017
Cloudy and unseasonably warmer weather will continue for the
North Country through the weekend. The start of the work week
brings a more active period of weather. A moisture laden low
pressure system will slowly track towards the northeast from
the Gulf coast states will bring a wintry mix to the North
Country, along with the potential for strong and gusty winds,
especially along the western slopes of the Green Mountains.
Behind that low pressure system expect continued unsettled
weather with temperatures still unseasonably mild.
.NEAR TERM /THROUGH MONDAY/...
As of 1143 PM EST Saturday...Fog will remain the forecast
challenge through the overnight hours. Seasonable high dewpoints
and dewpoint depressions between 1-3 degrees has combined to see
patchy dense fog already formed across much of northern New
York. Expect overcast skies through the overnight hours with fog
developing across most of the North Country this evening. With
the fog and overcast skies we may be a degree or two warmer than
the current min forecast but I left it along for the time
High pressure at the surface and aloft through 500 mb will
continue through the near term period, although the surface
ridge shifts east to the Gulf of Main coast while upper ridge
flattens in advance of approaching trough. Plenty of moisture
locked near the surface below 850 mb, and while some webcams are
showing breaks in the overcast expect skies to remain
predominantly overcast through the near term period. Despite the
cloud cover temperatures will remain mild and show little
diurnal change. Overnight lows in the 30s limited by cloud cover
and dewpoints in the low 30s, while max temps Sunday similar to
today in the upper 30s to low 40s. Patchy light fog will
redevelop tonight in moisture laden boundary layer.
.SHORT TERM /MONDAY NIGHT THROUGH TUESDAY NIGHT/...
-- Changed Discussion --As of 350 AM EST Sunday...High pressure retreating far to our
north and east and mild air over the North Country will set up
for complex thermal profiles as low pressure system approaches
from the DelMarVa coast Monday night. Precip north of the low
will spread from south to north accompanied by a tight pressure
gradient and strong easterly 850mb jet. As precip spreads across
the North Country, NAM and GFS BUFKIT soundings show warm layer
mainly between 800-700mb resulting in widespread wintry mix
into Tuesday morning. Models currently suggest sleet/snow mix
being the predominant PType for most of the area. With initial
surge of moisture expect most areas to see 1-4 inches of snow
sleet mix through Tuesday morning. As low continues to track
near the coast, reaching SE Long Island midday Tuesday PWATS
increase to around three quarters of an inch Monday night and
Tuesday. Associated 500mb trough becomes more negatively tilted
resulting in warmer air aloft moving into eastern VT and
transitioning precip to rain for the latter half of Tuesday. The
surface low continues NEwd toward the coast of Maine into
Tuesday night with colder air eventually moving into the North
Country and ending the precip at snow as it begins to taper off
Tuesday night into early Wednesday. Storm total snow/sleet
accumulations through 12Z Wednesday will generally range from 2
to 5 inches, with higher amounts possible depending on how long
the warm layer remains in place, how quickly the colder air
moves in as the surface low moves NE.
The strong 850mb jet Monday night into early Tuesday will lead
to downsloping winds, easterly slope enhanced precip and
westerly slope/valley shadowing. With steady precip and cloudy
skies, do not think low level jet will be able to fully mix
down, resulting in gusts of 20 to 30 mph in most valleys with
stronger gusts for south central Vermont of 30 to 40 mph and
higher at the summits of Vermont and northern NY.
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.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
-- Changed Discussion --As of 350 AM EST Sunday...Lingering snow showers expected but
overall active period continues as we remain under 500mb
troughiness. Quick moving low forms in the lee of the Rockies
and arrives for the latter half of Wednesday with rain/snow
showers expected to be light. Low chances for rain/snow showers
continue into the weekend. Above normal temperatures close out
the work week with a cooling trend. Saturday temperatures strive
to be within 5 degrees of normal for late January.
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.AVIATION /09Z Sunday THROUGH Thursday/...
Through 06Z Monday...Low level moisture trapped beneath
inversion layer will maintain MVFR/IFR ceilings through the next
24hrs with HIR TRRN OBSCD. The inversion doesn`t look likely to
break so the low level stratus will persist through the TAF
period with patchy fog across the northern New York sites.
Expect MVFR ceilings at all sites except IFR at SLK/MSS. Late in
the TAF period by 00-06z tomorrow expect the inversion to
finally break and see gradual improvement towards VFR ceilings.
Visibilities will be reduced to MVFR/IFR at MSS/PBG/SLK due to
the patchy dense fog. Expect visibilities to improve shortly
after daybreak tomorrow in the 12-13z time frame.
Outlook 06Z Monday through Thursday...
06z Sunday - 18z Monday...MVFR to IFR ceilings and visibility
Sunday night and Monday improve to VFR for a short time Monday.
18z Monday through Thursday...Conditions deteriorate to IFR
with widespread wintry mix of precipitation moving in late
Monday into Tuesday, then temperatures cooling to support snow
through Thursday. Strong southeast downslope winds on
Monday...especially at KRUT, with gusts in excess of 25kts
possible. Brief period of improving conditions possible early
Wednesday, before occasional SW renews. Thursday area coverage
of showers becomes more patchy through Thursday.