Area Forecast Discussion
Issued by NWS Burlington, VT-- Highlight Changed Discussion --
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FXUS61 KBTV 311414
Area Forecast Discussion
National Weather Service Burlington VT
1014 AM EDT TUE MAY 31 2016
A weak disturbance passing north of the region this afternoon will
bring scattered clouds and perhaps a few light showers or sprinkles
to northern mountain communities. Otherwise dry and seasonably warm
conditions are expected through Thursday as high pressure builds
across the northeast. A trend toward cloudier, more unsettled
weather returns by Friday, and again from Sunday onward into early
.NEAR TERM /UNTIL 11 PM THIS EVENING/...
-- Changed Discussion --As of 1014 AM EDT Tuesday...Forecast on track for the rest of
this morning into the afternoon under weak area of high pressure
in a seasonably mild and low humidity conditions. Plentiful
sunshine should persist across much of the area for the next
several hours. Steep low-level lapse rates driven by the strong
insolation should help mix gusts up to 25 mph at times this
afternoon, as well as tap into deep area of dry air aloft and
lower dewpoints into the afternoon. Focus then turns to cold front
and parent vorticity maxima now nearing the Ottawa Valley in
QC/ON. While a mainly dry frontal passage is expected late in the
day/early evening, it should act to increase clouds and veer winds
from west to northwest later in the day for our northern areas. So
I`ve increased sky cover slightly in these northern areas
(along/north of a line from St. Johnsbury to Montpelier to Saranac
Lake) for the afternoon period. Otherwise, I`ve just populated
with current observations. Highs today still look good, into the
70s to the lower/mid 80s but with noticeably lower humidity levels
compared to the Memorial Day weekend.
Prior discussion from 300 AM EDT Tuesday...
Generally quiet weather is expected over the next 24 hours and a
largely persistence forecast was offered for this morning`s
package. For today we`ll start the day mainly sunny, then trend
partly sunny by afternoon as a shortwave upper trough passes to
our immediate north and into northern Maine and the maritimes by
this evening. The feature has little moisture to work with, and
given a relatively dry boundary layer and thermal capping near 750
mb I`ve maintained our prior idea of just an outside shot of a
passing light shower or sprinkle across the northern mountains
later today. Best shot of occurrence across north
central/northeastern VT in closer proximity to upper energy.
Model-averaged 925 mb temperatures support highs in the 70s to
locally in the lower 80s in Champlain/Connecticut River Valley
communities where modestly gusty west-northwest boundary layer
flow will foster adiabatic downsloping effects.
By tonight surface high pressure continues to build into the region
as upper heights rise over time. Any evening cloudiness will trend
mainly clear overnight as west to northwesterly winds become light
after midnight. While confidence is only modest given a full 24
hours of drying, favorable hydrolapse profiles and lighter nocturnal
boundary layer wind fields suggest including at least shot of some
patchy mist and/or fog across the northern mountains in the 200-700
am time frame. Low temperatures a blend of MOS-based and bias-
corrected output which support values ranging through the 40s to
around 50 in milder valley locales.
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.SHORT TERM /11 PM THIS EVENING THROUGH WEDNESDAY NIGHT/...
As of 336 AM EDT Tuesday...Ridge of high pressure will crest over
the region on Wednesday. This will result in dry conditions, warm
temperatures and mostly clear to partly cloudy skies. As 925mb
temperatures increase to the mid teens, surface temperatures will
reach the 70s to low 80s on Wednesday. Areas east of the Greens
may be slightly cooler as models trying to indicate some light
easterly to southeasterly flow may bring some maritime are into
Wednesday night will remain dry and mild with increasing clouds
ahead of low pressure system and associated cold front approaching
from the west. Aforementioned ridge will shift east over the
Canadian maritimes, bringing return southerly flow to the North
Country. Min temperatures will generally be in the 50s.
.LONG TERM /THURSDAY THROUGH MONDAY/...
As of 336 AM EDT Tuesday...Potential for rain showers and
thunderstorms increase on Thursday as low pressure system nears. A
weak warm front will graze Northern New York, with increasing POPs
throughout the day, while the Champlain Valley and areas east are
expected to remain dry. Max temperatures will be slightly warmer
and dependent on cloud cover, ranging from the 70s to low-mid 80s.
Cold front associated with the low is expected to move across the
region Thursday night through Friday. Depending on timing,
thunderstorms could develop. While bulk of energy exits the North
Country to the south and east late Friday/Friday night, models
indicate another vort at 500mb moving through late Friday
night/early Saturday morning which will keep slight to low chance
POPs over the area.
High pressure arrives for the bulk of the weekend, providing a
break in precip potential, before a long wave mid-level trough
digs southward from the Great Lakes Region. Models show some
differences with regard to evolution, track and timing of this
system. Similarities exist in the surface low becoming a cut-off
low and could lead to a wet first half of the week.
Temperatures throughout the period will remain above normal by
5-10 degrees for this time of year.
.AVIATION /14Z Tuesday THROUGH Saturday/...
Through 12z Wednesday...Mainly VFR through the forecast period.
Winds generally light to modest west to southwesterly this
morning, veering west to northwesterly after 16Z and occasionally
gusty to 20 kts this afternoon before abating by 00Z. SCT to
occasionally BKN cigs mainly in the 045-070 AGL range arrive after
16Z or so as weak upper disturbance swings by to the north. Other
than a brief northern mountain sprinkle, no precipitation is
expected with this feature. After 06Z trending mainly SKC though
have included a brief period of IFR vbys/cigs at KSLK in the
08-11Z time frame to account for favorable hydrolapse rates and
potential br/fg. Outside shot of this also occurring at the KMPV
terminal during the same time frame but given lower surface
moisture fluxes overall confidence is lower so have refrained
from mentioning at this point.
Outlook 12Z Wednesday through Saturday...
12Z Wednesday through 00Z Friday...VFR/high pressure.
00Z Friday through 00Z Saturday...VFR with brief MVFR visibilities
possible in scattered showers as weak frontal boundary swings
through the area.
00Z Saturday onward...mainly VFR/high pressure.