FXUS61 KBTV 191136
Area Forecast Discussion
National Weather Service Burlington VT
736 AM EDT Sun Aug 19 2018
High pressure will build in today, supplying fair weather
through Monday. A warm front will move through late Tuesday,
spreading showers over the area Tuesday night. Precipitation
will taper off Wednesday as a cold front passes, followed by dry
weather and seasonable temperatures to finish the week.
.NEAR TERM /THROUGH MONDAY/...
As of 553 AM EDT Sunday...Patchy dense fog will lift over the
next few hours once solar radiation is able to induce enough
turbulent mixing. Tweaked temperatures to match observations for
the early morning update, otherwise forecast on track.
Previous discussion...Patchy fog remains the main forecast
challenge overnight. High pressure building in, clear skies,
calm winds, and recent rainfall have created the ideal scenario
for fog development over the North Country. Satellite imagery
shows fog locked in to climatologically-favored valley
locations, with patches of fog elsewhere. Light easterly flow
just off the surface has allowed for fog developing over the
Winooski River to drift over the airport, resulting in 1/4 to
1/2 sm visibilities over KBTV through the night. Elsewhere in
Burlington, webcams show some mist but not the dense fog being
observed at the airport. Looking at observations/webcams
throughout the forecast area, patchy fog seems to be the rule.
Expect fog to lift shortly after sunrise, giving way to a very
High pressure will crest to our northeast this
afternoon/evening, providing enough subsidence over the
forecast area to keep precip chances at or near zero. 925 mb
temperatures progged around 18/19C and a well mixed boundary
layer will translate to high temperatures in the upper 70s to
low 80s (quite a few degrees warmer than yesterday`s readings).
Mostly clear skies tonight will allow for effective radiational
cooling, so have trended towards the lower side of MOS guidance
for forecast overnight lows. Areas of the northern Adirondacks
in New York along with the Northeast Kingdom of Vermont will dip
into the mid to upper 40s tonight, while the remainder of the
area will see overnight lows in the 50s. Could see some patchy
fog develop again tonight, however given that we will be a
little more removed from Friday/Saturday`s precipitation, not
expecting the fog to be as widespread or dense tonight as what
is being observed this morning.
High pressure will shift offshore over the Canadian Maritimes
Monday, allowing for some light return southerly flow to
develop. Accordingly, temperatures will be a degree or two
warmer Monday than Sunday. Climbing dewpoints will make for a
slightly more muggy feel to the air Monday, but with dewpoint
readings still remaining generally below 60, the increase in
humidity will be subtle.
.SHORT TERM /MONDAY NIGHT THROUGH TUESDAY/...
As of 244 AM EDT Sunday...Upper ridging exists over the area Monday
night and upstream trough is still well back across the Upper
Midwest. As a result...dry weather is expected Monday night and it
now looks like any precipitation will not move into northern New
York until during the day on Tuesday and the precipitation will stay
out of western Vermont until late in the day. No precipitation is
expected east of the Green Mountains. Low temperatures Monday night
will be in the mid 50s to mid 60s and then with increasing clouds on
Tuesday high temperatures will be in the mid 70s to lower 80s.
.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
As of 244 AM EDT Sunday...Eventually the upper trough moves across
the region Tuesday night and then gradually exits the area later on
Wednesday. Showers should become widespread across all of northern
New York and Vermont later Tuesday night with anywhere from a
quarter to half inch of rain expected. By Wednesday morning there
should be a west to east precipitation gradient with showers likely
across Vermont and a chance of showers over northern New York. Could
see another tenth to quarter inch of rain. Some lingering showers
will exist over eastern Vermont Wednesday evening...but then dry
weather is expected Thursday through most of Saturday as ridging...
both at the surface and aloft...moves into the region. Highs
Wednesday and Thursday will be in the 70s with clouds and showers
holding temperatures back on Wednesday and then cold air advection
on backside of upper trough on Thursday. When the ridging builds in
Friday into Saturday highs will warm back up into the mid 70s to
.AVIATION /12Z SUNDAY THROUGH THURSDAY/...
Through 12z Monday...Patchy dense fog continues, affecting KBTV
and KMPV with LIFR visibilities. Now that the sun has risen,
expect fog should lift over the next couple of hours. By 14Z,
expecting widespread VFR conditions that will prevail though
06Z. After 06Z, will see some patchy fog develop once again,
resulting in decreased visibilities. However, not expecting fog
to be as widespread or as dense tonight as what was observed
this morning. Have included some reduced visibilities at KMSS
and KSLK between 06Z and 12Z, elsewhere confidence is not high
enough to include in TAF at this point. Winds will generally be
easterly/northeasterly today under 10 kts, then becoming light
and variable overnight.
Monday: VFR. NO SIG WX.
Monday Night: VFR. NO SIG WX.
Tuesday: VFR. Chance SHRA.
Tuesday Night: Mainly MVFR, with areas VFR possible. Likely SHRA.
Wednesday: Mainly MVFR, with local IFR possible. Likely SHRA.
Wednesday Night: Mainly VFR, with areas MVFR possible. Slight
Thursday: VFR. NO SIG WX.