Area Forecast Discussion
Issued by NWS Burlington, VT
FXUS61 KBTV 291928
Area Forecast Discussion
National Weather Service Burlington VT
328 PM EDT Thu Sep 29 2016
Fair and dry weather continues as high pressure over Quebec
builds over the North Country through Friday. A closed upper low
over the Ohio valley will linger there through Saturday. This low
will move northward into the Great Lakes Saturday night into
Sunday. Moisture from the closed upper low will bring increasing
chances for rain showers to the North Country this weekend through
.NEAR TERM /THROUGH FRIDAY/...
As of 328 PM EDT Thursday...The North Country stays dry through
Friday as a ridge of high pressure resides over Quebec keeping a
cutoff low over the Ohio River Valley. Models continue to indicate
500mb heights increasing over the North Country with mid-high
level clouds pushing northward over northern New York. Any rain
showers associated with deeper moisture over western and central
New York dissipate in the drier air over the St Lawrence Valley
and Adirondacks as dewpoints generally in the low to mid 40s. The
cutoff low meanders a little southward around the Ohio Valley,
likely seeing a brief retreat in clouds overnight, but Friday
afternoon will see deeper moisture spread northward into southern
portions of the forecast area. With PWATs increasing to around 1
inch late in the day, lower clouds and possibly some late period
showers begin to edge in from the south. Have included slight to
low chance POPs near southern CWA border late Friday.
Min temps tonight ranging from the mid 30s to upper 40s. Friday
max temps will vary on cloud cover and cloud depth; with overall
less sunshine, expect temperatures to be a few degrees cooler than
.SHORT TERM /FRIDAY NIGHT THROUGH SATURDAY NIGHT/...
As of 307 PM EDT Thursday...
The North Country will still be under the influence of two main
weather features during the short-term period: a lingering ridge
of high pressure extending from Maine into the eastern half of the
North Country, and the very slow-evolving upper low centered over
the Ohio Valley and its associated northward feed of Atlantic
moisture on its extreme eastern periphery. The main forecast
challenges in this period will be on temperatures and identifying
a period when PoPs may be more focused. Specific to the latter
point, there remains little clarity on when there may be a more
widespread period of rain as dry surface to 850 mb air should
limit areal coverage. The 12z NAM is the most aggressive in
showing QPF across our area on Friday into early Saturday. Feel
this is more overdone as compared to the 09z SREF and the 12z GFS
which is a lot more spotty. Through Friday night and early
Saturday morning, PoPs are kept generally under Chance except for
the extreme southern part of Vermont. Precipitation would also
likely show a good component of southeasterly upslope with highest
precip chances along the eastern spines of the Greens and
Adirondacks and lower in the Champlain and St. Lawrence Valleys on
the lee side. PoPs then begin to increase into the Chance/low
Likely range for the second half of Saturday into Saturday night
as mid-upper flow becomes more diffluent and might be just enough
to spark a greater coverage of light showers.
Temperature trends through the short-term period will be largely
governed by mostly cloudy to overcast skies, with milder than
normal lows but below-normal highs. Lows Friday night are
generally coolest north (in the low 40s) to the mid/upper 40s
south and in the valleys. Clouds and off-and-on light showers
keeps highs Saturday a rather raw upper 50s to lower 60s east to a
somewhat milder mid 60s for the St. Lawrence Valley. Little change
to lows from daytime highs Saturday night in the 40s to mid 50s.
.LONG TERM /SUNDAY THROUGH THURSDAY/...
As of 307 PM EDT Thursday...
Upper low through the previous period undergoes a deamplifying
trend into more of an open wave Sunday into Monday. Focus for
highest PoPs would generally be Sunday into Monday but it`s worth
pointing out that precipitation would be more showery in nature,
meaning that not everyone would see rain and it would not amount
to very much. Still some lingering slight chance PoPs on Tuesday
but the weaker open wave then merges with a northern stream trough
with a dry trend then offered for Tuesday night. A good stretch of
dry weather looks to be the case with a broader diurnal range in
temps for the mid-week period. Temperatures stay generally a few
degrees above normal through the period, though expect to see more
cooler nights Wednesday and Thursday with more clear skies.
.AVIATION /19Z Thursday THROUGH Tuesday/...
Through 18Z Thursday...VFR conditions persist through the
afternoon. Overnight, there is a chance for fog development mainly
affecting KSLK and KMPV with the greater chance for IFR/LIFR fog
development at KMPV (after 08z) as clouds will be slower to move
into the terminal.
Winds vary widely this afternoon as NE flow is gusty over KMSS
and KSLK but look to dissipate this evening. calm to light winds
expected overnight and slow to pick up Friday morning.
Outlook 18z Thursday through Tuesday...
18z Thu - 12z Sat: VFR under an increasing clouds.
12z Sat - 12z Tue: Mix of VFR/MVFR in scattered rain showers,
mainly from 00z Sun onward.
12z Tue onward: Generally VFR as rain showers depart eastward and
surface high pressure builds into the North Country.