Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Burlington Vermont
155 PM EDT Sat Jul 4 2015
a few scattered showers are possible across the region this
afternoon and early tonight. Temperatures will hold in the 70s
today with more clouds...but will be warmer on Sunday with
Near term /until 6 PM this evening/...
as of 155 PM EDT Saturday...composite radar loop showing showers
across southern Vermont shifting slowly eastward into New
Hampshire at this time. Composite radar loop also showing some
scattered showers over the Adirondacks at this time. Have kept in
a slight chance for thunderstorms this afternoon across the
Adirondacks as laps analysis showing some destabilization there at
this time. Have kept the Saint Lawrence valley dry as dew points
at Massena have dropped with somewhat drier air moving in there at
this time. Have lowered probability of precipitation to slight chabnce for most areas for
the remainder of today and tonight.
Short term /6 PM this evening through Monday/...
as of 400 am EDT Saturday...northern stream 500 mb vorticity will swing
across our County Warning Area this evening...while ribbon of enhanced 850 to
500mb moisture quickly shifts into northern Maine by 06z. Any
showers will weaken or be east of our County Warning Area by midnight tonight.
Will continue to carry chance probability of precipitation during the evening hours...with
the main focus for scattered showers across the eastern dacks into
central/northern Vermont...including the Champlain Valley. Given timing
of showers...some evening activities associated with the Holiday
maybe impacted...especially across the northern cpv valley into
parts of northern Vermont between 00z and 03z. Expect areas of clearing to
develop after 06z with 1021mb surface high pressure building into our County Warning Area.
Some patchy fog/br is possible toward sunrise...especially over
the deeper/protected river valleys of the dacks. Low temperatures will be
highly depend upon clearing...mainly 40s mountains valleys to middle/upper
Sunday and Monday...mid/upper level ridge develops across the NE Continental U.S.
With weak surface high pressure. Still noticing another 500 mb vorticity in the northwest
flow aloft impacting northern Vermont between 18z-00z Sunday...which may
produce a few sprinkles. Moisture is very limited. Prognosticated 850 mb temperatures
near 12c...support lower 70s mountains/nek to near 80f warmer valleys
on Sunday. Monday will feature mostly sunny skies and mild temperatures.
Prognosticated 850 mb temperatures warm between 12c and 14c...supporting middle/upper 70s
mountain towns to lower 80s valleys.
Long term /Monday night through Friday/...
as of 400 am EDT Saturday... a hint of Summer next week as
heights and temperatures rise to or just above normal with a surge
of moisture and some thunderstorms on Tuesday. Thereafter...still lots
of questions/differences on timing/progression of front that
delivers our rain showers/thunderstorms and rain late Tue/Wed.
Rest of discussion taken from dayshift as same issues/questions of
past few days.
Short wave ridging on Monday bringing temperatures in the 80s with 850
temperatures rising to 14-15c will be pushing east Monday night and Tuesday.
Models similarly increasing humidity and instability (1000-2000j/kg
cape) on Tuesday ahead of a frontal system as southwest flow advects
moisture into the region. So that will increase our chances of
showers and thunderstorms through through Tuesday night. Little
change in 850 temperatures so temperatures again in the middle 80s.
Where models differ is on how fast the frontal system moves through
with GFS bringing front through by Wednesday morning while European model (ecmwf) is
slower and brings it through later in the day. Both models show
upper trough weakening and lifting north, so not expecting a deepening
trough like we've had lately. The timing of the front would make a
significant difference in the convective probabilities, so went with
a blend with showers and a slight chance of thunderstorms hanging
around on Wednesday. Temperatures a bit cooler on Wednesday.
Some uncertainty continues Thursday-Friday as flow aloft is generally
westerly with weak troffing so can't completely rule out a shower
with temperatures near normal for this time of year (80/60).
Aviation /18z Saturday through Thursday/...
through 18z Sunday...VFR conditions are expected through the period.
Upper disturbance moving through the region this afternoon/evening
will provide variable cloudiness though ceilings will remain VFR. A few
popup showers are also possible across northern terminals of
kslk/kpbg/kbtv but should be very light with no ceiling/visibility
restrictions expected. Southerly winds 5-10kts this afternoon go
light overnight, turning to the west/southwest Sunday except for
kpbg where direction will be southeast due to lake breeze
Outlook 18z Sunday through Thursday...
18z sun - 12z Tue: VFR. IFR fog possible at kmpv/kslk 08-12z Monday.
12z Tuesday - 00z Thu: VFR west/scattered MVFR thunderstorms and rain possible.
00z Thursday - 00z Fri: VFR. Early morning IFR fog possible at kmpv/kslk.
ktyx radar will be out of service until Tuesday or later.
equipment...weather forecast office btv