250
FXUS61 KBTV 150615
AFDBTV
Area Forecast Discussion
National Weather Service Burlington VT
215 AM EDT Sat Aug 15 2026
.WHAT HAS CHANGED...
As of 215 AM EDT Saturday...
Increasing chances for 1" or greater rainfall in northern
Vermont Sunday night into Monday morning.
&&
.KEY MESSAGES...
As of 215 AM EDT Saturday...
1. Much of the weekend will be dry, then rain Sunday evening
through the overnight hours is expected.
2. Scattered showers on Monday will give way to another drier
period Monday night into Tuesday.
3. Near seasonable temperatures with a chance of showers mid to
late next week.
&&
.DISCUSSION...
As of 215 AM EDT Saturday...
KEY MESSAGE 1: Surface high pressure is building into the region today,
which will maintain a slightly cooler than normal air mass with
abundant dry air aloft. The low humidity pattern will flip beginning
Sunday afternoon, and especially evening, as this high exits to our
east and increasing moisture transport from the southwest occurs
ahead of an occluding area of low pressure moving into the eastern
Great Lakes.
It continues to appear that weakly unstable air aloft will
support moderate rainfall rates (as high as an inch/hour), and a
few rumbles of thunder at times. The heavier showers should
tend to be at the nose of a strengthening nocturnal low level
jet (850 millibar winds increasing to around 30 knots or so).
The placement of the heavier rain is rather uncertain at this
time and will tend to be wherever a north-south moisture
gradient sets up overnight. The latest guidance shows a broad
consensus in portions of northern/northeastern Vermont, but
given large spread in recent forecast cycles of where heavier
footprints of rain will fall we have maintained a blend showing
roughly 0.5" of rain in much of our region. The event total 75th
percentile looks like reasonable higher end rainfall amounts,
showing potential for swaths of rainfall in the 1-1.5" range in
Vermont with less potential in the Adirondacks and points west.
If heavier rain occurs farther south, the southwesterly low
level flow will support locally heavier totals in the vicinity
of the Green Mountain National Forest. Antecedent dry
conditions and lack of a stationary boundary or setup for
training showers are limiting factors for flash flood risk, such
that a marginal (level 1) excessive rainfall outlook looks
reasonable for our region. The steady rain will exit to our east
towards Monday morning with the departure of isentropic lift
and a broad area of surface low pressure into the region.
KEY MESSAGE 2: A deeper area of low pressure over northern Quebec will
be dragging a weak cold front through the area during the day on
Monday. In the wake of the early morning rain, there will be plenty
of shallow moisture/elevated dew points such to support scattered to
numerous showers during the day ahead of this front. Any modest
heating will increase instability, although shallow cloud tops are
expected due to a wedge of warm, dry air aloft and limit downpour
intensity with low chances for thunder. As drier air continues to
filter through on deepening west-northwesterly flow, rain chances
will become orographically forced with otherwise increasing sunshine
through the later part of the day.
KEY MESSAGE 3: Pretty much remain in a broad cyclonic flow that is
dominating the Great Lakes-NY-New England. Heat ridge remains mainly
across southern-southwest tier of CONUS. Our CWA is far enough from
the periphery of the ridge that we stay largely influenced by
the northern stream flow with seasonable temperatures and a
chance of showers now and then. The best chance for showers will
be late Wed- Thu with a northern stream system.
&&
.AVIATION /06Z SATURDAY THROUGH WEDNESDAY/...
Through 06Z Sunday...Calm and variable winds will continue as
high pressure nudges in from the northwest. Outside of any
variable winds, northerly flow aloft will prevail through the
TAF period. Clouds are clearing after sunset with some patchy
fog possible in the climatologically favored terminals. Winds
likely will decouple at most sites and have trended favored
sites towards prevailing fog tonight at SLK/MPV with
intermittent IFR fog potentially at EFK/RUT and vcnty of KBTV.
Fog will lift between 12-13Z where it develops. Winds will
become prevailing from the north-northwest after sunrise
tomorrow with mostly clear skies.
Outlook...
Sunday: VFR. Slight chance SHRA.
Sunday Night: Mainly MVFR, with areas IFR possible. Definite
SHRA, Slight chance TSRA.
Monday: Mainly MVFR, with areas IFR possible. Likely SHRA, Slight
chance TSRA.
Monday Night: Mainly VFR, with local MVFR possible. Slight chance
SHRA.
Tuesday: Mainly VFR, with local MVFR possible. NO SIG WX.
Tuesday Night: VFR. NO SIG WX.
Wednesday: VFR. Chance SHRA.
&&
.BTV WATCHES/WARNINGS/ADVISORIES...
VT...None.
NY...None.
&&
$$
WHAT HAS CHANGED...Kutikoff
DISCUSSION...SLW/Kutikoff
AVIATION...SLW
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