Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Burlington Vermont
345 PM EDT Wed Jul 27 2016
a few showers or thunderstorms possible this evening near the
Canadian border. Better chances for showers and storms arrive
Thursday as a trough of low pressure moves into the region.
Showers over the southern areas expected Friday and Sunday.
Saturday looks to be the drier day of the weekend. Seasonal
temperatures will close out the week and persist into early next
Near term /through Thursday/...
as of 345 PM EDT Wednesday...dry weather persists through the
rest of this afternoon, then a few showers and isolated
thunderstorms will affect northern New York and northern tier of Vermont as a
weak disturbance moves in from southeastern Ontario this evening.
Expect potential for precipitation to diminish after midnight with
light to calm winds. Morning low temperatures will be dependent on
cloud cover, which will be increasing from the west/northwest as a
mid level trough approaches. Expect temperatures to range from the
upper 50s to the upper 60s.
Thursday will be more active with showers and thunderstorms in
the forecast as 500mb trough affects the area. In the morning
hours, showers will develop becoming more numerous in the late
morning/early afternoon with thunderstorm activity expected.
Negative showalters, lifted indices of -2c to -6c, cape values
anywhere from 800-1400j/kg support convective activity. Looking at
wind shear, there will be light low level flow and, therefore,
minimal low level shear. Early Thursday, an 80-90kt jet at 250mb
with 0-6km shear of 30-35kts to start the day and weakening in the
afternoon. Pwats exceed 1.5 inches in areas by early afternoon
along with steepening lapse rates. Overall expect an early show,
with greatest potential for thunderstorms during the midday hours.
Few thunderstorms could become strong before vort Max providing
lift begins to exit south and east and activity gradually
Max temperatures tomorrow will be slightly warmer than normal, in
the upper 70s to mid 80s.
Short term /Thursday night through Friday night/...
as of 345 PM EDT Wednesday...focus for the short term period will
continue to be a weak frontal boundary as it slowly sags southward
through the btv County Warning Area Thursday night, and stalls somewhere near/over
the Vermont/NH/MA border on Friday. Convective activity wanes going
into Thursday evening/night with the loss of instability due to
decreasing insolational heating. Moving on into Friday, latest
trends are for additional precipitation to Blossom along the
stalled frontal boundary as weak shortwave energy aloft shifts
east from the Ohio River valley into the mid Atlantic states. This
places the best chances for scattered showers and isolated
thunderstorm across southern Vermont, while areas north will
remain largely dry. Much like on Thursday, instability and shear
are rather weak, so not expecting any strong storms, but a few
more robust cells that do develop will have the potential to
produce brief heavy rain as pwats remain in the 1.5-1.75" range.
Br Friday evening, any precipitation will begin to dissipate while
shifting eastward as high pressure begins to build in from the
Great Lakes temps remain on the mild side of normal to begin the
period on Thursday night, holding in the upper 50s to low 60s, but
trend back towards mid/late Summer standards with highs Friday in
the upper 70s to low 80s, and lows Friday night ranging through
Long term /Saturday through Tuesday/...
as of 345 PM EDT Wednesday...overall idea for the long term
period remains intact from previous forecast thinking with surface
high pressure over the eastern Great Lakes on Saturday slowly
shifting east to off the New England Seaboard by early next week
while aloft the flow remains out of the west/northwest. This
offers mainly dry conditions through the period though latest
guidance indicates a weak shortwave will bring a chance for a few
showers to southern areas during the Sunday afternoon through
Monday timeframe as it tracks from the Ohio River valley to Cape
Cod. Overall this energy is fairly weak, so will just offer some
low chance pops across Rutland/Windsor counties while northward
keep the forecast dry. Temps through the period begin very
seasonal with highs over the weekend in the upper 70s to lower
80s, and lows in the 50s. As the high shifts east of the forecast
area, increasing southerly flow will allow for a return of warmer
and more humid conditions with temperatures rising a couple of
degrees each day, reaching into the mid 80s to near 90 by
Aviation /19z Wednesday through Monday/...
through 18z Thursday...VFR conditions will prevail with exception
of IFR/LIFR fog develop possible at kslk and kmpv mainly between
07z-11z Thursday morning. Few/isolated showers/tstorms north of
the international border could eventually affect St Lawrence
Valley across northern New York and northern Vermont late today. Have
included vcsh at kmss around 22z.
Otherwise, Thursday mid morning will see widespread VFR
conditions but mid level clouds increasing with afternoon
Outlook 18z Thursday through Monday...
18z Thu - 00z Sat: VFR with MVFR/IFR possible in isolated to
scattered showers and thunderstorms during the daytime Thursday
00z Sat - 00z Tue: VFR.