Scientific Forecaster Discussion
fxus61 kbtv 260533
Area forecast discussion
National Weather Service Burlington Vermont
133 am EDT Fri may 26 2017
intermittent showers will persist during the overnight hours. A
developing coastal low near Long Island will bring an additional
period of steady rainfall during Friday morning. Friday will be
cloudy and cool overall with high temperatures remaining in the
50s. The upcoming weekend will feature a dry Saturday with some
scattered showers possible Sunday night into Monday.
Near term /until 6 PM this evening/...
as of 1011 PM EDT Thursday...southeasterly wind gusts continue
to decrease along the western slopes of the Green Mountains late
this evening. Still a couple of isold gusts 35-39mph at Wells
and Mendon, Vermont...but overall trend is downward and we've chosen
to cancel the Wind Advisory a couple of hours early (at 02z).
Please see our public information statement from earlier this
evening for peak wind gust information along the western slopes.
Center of slow-moving/closed 500mb low is located across wrn PA
and far swrn New York at 02z. Mid-level dry slot on ern periphery of
the low center had shifted nwd into our region, but is no
disappearing from WV imagery as new cyclogenesis takes hold
south of Long Island. Seeing some fast moving showers moving
north-northwestward across central Vermont and the ern slopes of the Adirondacks.
However, there will be another round of more significant rain
toward daybreak (09-10z) as activity south of Long Island wraps
north-northwestward in newly forming cold conveyor belt around coastal low.
This will set up a rather raw/cloudy/rainy Friday with high
temperatures generally in the 50s. Afternoon high temperatures
will be about 15 deg below normal for late may. Light NE winds
will back into the north toward dawn with winds generally north-NE
10-15 mph during the daylight hours on Friday.
Short term /6 PM this evening through Saturday night/...
as of 350 PM EDT Thursday...vertically stacked low pressure
system near Nova Scotia Friday evening moves east and out to sea
overnight Friday night. Some lingering light rain showers or
drizzle early will gradually dry up from west to east with some
gradual clearing by Sat morning. Lows mainly in the 50s.
Saturday will see weak surface high pressure build in to start
the Memorial Day weekend. Partly cloudy skies and 850 temps of
8-10c will yield warmer temperatures with highs 70s. Lows in the
mid 40s to mid 50s.
Long term /Sunday through Thursday/...
as of 350 PM EDT Thursday...
The long term starts out on Sunday with an upper level ridge over
the East Coast with a developing light southwest flow at the surface
as weak high pressure moves out to sea east of New England. 850mb
temps are around 10-11c which should yield high temps in the 70s
perhaps upper 70s in the valleys.
As the ridge shifts east, cloud cover increases in the afternoon and
evening as an upper level low pressure system tracks west of the
Great Lakes with warm advection during the overnight hours into
early Memorial Day with a period of showers. A weak cold front
Monday evening trough will swing through with shortwave energy,
bringing with it showers with perhaps a thunderstorm or two
with some marginal instability.
Tuesday through Thursday there will be on and off mainly afternoon
and evening showers as a second cold front and several Post
frontal trofs swing through the region. Cold advection will
bring 850mb temps down from 8-10c on Tue to around 6c Wed and 4c
on Thu. The cold advection and daytime heating will contribute
to very weak instability and scattered showers. Corresponding
high temperatures will be start out in the 70s on Tue falling
back into the 60s Wed and Thu. Lows will in the upper 40s to
Aviation /06z Friday through Tuesday/...
through 06z Saturday...very challenging first 6 to 12 hours for
our taf sites...as conditions change from VFR/MVFR to widespread
IFR. Radar shows a band of light to moderate rain rotating
toward our taf sites this morning and utilizing the hrrr
composite reflectivity has this at rut by 07-08z...mpv around
08z...and btv/pbg by 09z. Expecting cigs/vis trending toward
MVFR conditions with band of rain...and as winds shift to the
north/northwest btwn 10-14z this morning...expect IFR cigs to
develop in cpv...including pbg/rut/btv. Prevailing northeast
flow and low cigs already will keep mss at IFR conditions.
Latest soundings show cigs continuing to lower at slk as winds
shift to a northerly direction with IFR likely by sunrise.
Widespread IFR cigs likely by 14z...with periods of IFR vis
possible in the heavier convective shower elements. IFR cigs
will prevail into the evening hours...with a slow improving
trend toward 06z Saturday.
Saturday: VFR. No sig weather.
Saturday night: VFR. No sig weather.
Sunday: VFR. Slight chance rain showers.
Sunday night: VFR. Chance rain showers.
Memorial day: VFR/MVFR. Likely rain showers...tsra.
Monday night: VFR. Chance rain showers...tsra.
Tuesday: VFR. Likely rain showers.