975
FXUS61 KBTV 270519
AFDBTV
Area Forecast Discussion
National Weather Service Burlington VT
119 AM EDT Mon Jul 27 2026
.WHAT HAS CHANGED...
As of 236 PM EDT Sunday...
No significant changes to the forecast at this time. Still
anticipating daily scattered to numerous showers and possible sub
severe embedded thunderstorms through Thursday.
&&
.KEY MESSAGES...
As of 236 PM EDT Sunday...
1. Isolated to scattered showers and embedded thunderstorms are
expected this afternoon and tomorrow afternoon, mainly across the
Adirondacks, with isolated to scattered heavy downpours.
2. More widespread showers and thunderstorms are expected by
Tuesday, with the best chance for widespread precipitation expected
Wednesday as a slow moving system tracks through the region.
3. Trending drier heading into the first half of the weekend
before showers return for Sunday.
&&
.DISCUSSION...
As of 236 PM EDT Sunday...
KEY MESSAGE 1: High pressure will continue to drift northeast of the
Canadian Maritimes, putting the region in a col (or area between 2
lows and 2 highs), with little flow aloft or wind direction. To the
west, a weak shortwave will attempt to push east, but will encounter
lingering surface dry air, and thus will be shunted west of the
Champlain Valley. As this boundary works into northern New York
however, there will be enough forcing off the terrain to sustain
some isolated to scattered showers and embedded thunderstorms across
the Adirondacks and perhaps the St. Lawrence Valley. PWATS are about
0.5" above normal, and with little steering flow aloft, brief heavy
downpours will be possible. Increasing surface instability to
1500J/kg based on the current SPC Mesoanalysis across northern New
York bodes some confidence in scattered convection. These showers
and thunderstorms will be mainly pulse like storms, that bubble up,
but dont last long and come back down. There is a lack of any shear
or strong dynamics so no severe storms are expected, but any
collapsing shower could innately bring some breezes to the surface.
With decent PWATs to around an inch to an inch a quarter, briefly
heavy rain is possible. However, given the recent dry stretch
rainfall amounts will only be around a quarter to locally half an
inch.
Showers will wane with the loss of diurnally heating tonight. Should
a location in the Adirondacks get rain today, chances for localized
patchy fog will increase. A repeat of today is expected tomorrow,
though the shower and thunderstorm chances slide a but to the east
with dry air retreating. Pulse showers and thunderstorms will
develop in the early to mid afternoon across the terrain of the
Adirondacks and Green Mountains, and by and large should be
contained to the higher terrain. However, these showers could drift
east into the Champlain Valley or eastern Vermont by the mid to late
afternoon Monday, though chances are only 20-30%. Showers will once
again wane towards sunset Monday. Should across northern New York
receive multiple rounds of showers Sunday and then Monday, we`ll
need to monitor these areas for potential of flash flooding, but
this threat is highly conditional. The Weather Prediction Center
currently has most of northern New York, outside of the Champlain
Valley, under a Marginal Risk (Risk level 1 out of 4; 5% chance for
rainfall exceeding flash flood guidance) for Monday. Northern New
York rivers could see some small rises, but nothing near bankfull
with the recent dryness we have had. Better, more widespread rain
chances are expected by mid week.
KEY MESSAGE 2: A slow moving upper low is still expected to track
through the region by mid week with chances for persistent showery
weather into Thursday. The main long wave trough over the Great
Lakes will shift east into northern New York and Vermont by Tuesday
with a more established system. A nearly cut-off vertically
stacked surface low will move into the region with widespread
showers increasing from west to east Tuesday late morning.
Trends have continued to favor the center, and subsequently
better forcing, staying to our south over Long Island and
southern New England which places our region in the northern
periphery overrunning portion of the system. Tuesday will see
continued diurnally driven showers and thunderstorms with more
widespread coverage than Monday. Pwats look to increase towards
1.5-1.75 inches with around 500-1000J/kg of SBCAPE. These
ingredients could be supportive of heavy downpours, mainly
across the St. Lawrence Valley in New York and Rutland and
Windsor Counties in Vermont, though antecedent dry conditions
may continue to limit these pwat realizations. It is still
uncertain how far north the more widespread precipitation shield
extends, but right now it is likely that the best precipitation
chances and amounts will favor southern Vermont. Any areas that
see heavier downpours on Sunday or Monday will need to be
watched. By Tuesday, the WPC has the Marginal (at least 5%) Risk
of excessive rainfall over the entire forecast area. Because of
all these additional showers, thunderstorms, and general
moisture/clouds around, highs Tuesday will come back down just a
couple degrees, in the upper 70s to mid 80s.
The best chance for widespread showers will be Wednesday. The
low over southern New England looks to occlude with good wrap
around moisture transport off the Atlantic along the northern
edge of the system. Rain on Wednesday is not expected to be as
convective as previous days. By Wednesday, chances for an inch
of rain over 48 hours increase from 50-80% from south to north
across the entire region. Chances for 2 inches in 48 hours by
Wednesday night are generally under 20% for the area, outside of
southern Windsor County which is at 55% based on the latest
NBM. Southern Windsor County will have the best chance for any
higher rainfall amounts due to easterly flow. The current
rainfall forecast highlights these target areas with up to an
inch and three quarters locally possible in southeastern
Vermont, and around an inch to an inch and a quarter for the
rest of southern Vermont and northern New York Tuesday through
Wednesday. Half and inch to to an inch is expected from the
Northeast Kingdom to central Vermont and the northern Champlain
Valley. Wednesday is another period that the WPC has our entire
area under Marginal Risk of excessive rainfall. River rises will
be expected by Wednesday night following the bulk of the
precipitation, though current forecasts keep area waterways
below bankfull. Precipitation should limit temperatures on
Wednesday, reaching widespread 70s.
KEY MESSAGE 3: Lingering showers are likely on Thursday as the upper
level trough slowly exits the region and the occluded surface low
remains nearby. As they push to the east for Friday and Saturday,
conditions will trend mostly dry. While an isolated shower cannot be
ruled out, conditions will be almost completely dry. A cold front
attempts to push south into the region on Sunday, likely bringing
another rounds of showers with the potential for embedded
thunderstorms. Temperatures will be mostly seasonable during this
time, though likely trending slightly above average heading into the
weekend. No major heat is expected going into next week.
&&
.AVIATION /06Z MONDAY THROUGH FRIDAY/...
Through 06Z Tuesday...Aviation challenge is duration of fog at
SLK and potential fog development at MPV. Currently LIFR in fog
at SLK, but conditions have been bouncing between LIFR and VFR
as mid level clouds are impacting SLK. Thinking mostly
prevailing LIFR in fog thru 08-09z, before additional clouds
will produce intervals of IFR or lower conditions at SLK and
improving to VFR by 11z. MPV thinking a brief window of IFR or
lower conditions are possible between 09-11z. Otherwise, VFR
conditions prevail at the rest of our sites with light terrain
driven winds, becoming south/southwest 3 to 7 knots by mid
morning.
Outlook...
Tuesday: VFR. Chance SHRA, Chance TSRA.
Tuesday Night: Mainly VFR, with local IFR possible. Chance SHRA,
Slight chance TSRA.
Wednesday: MVFR/IFR conditions possible. Definite SHRA, Chance
TSRA.
Wednesday Night: Mainly VFR, with local IFR possible. Chance
SHRA.
Thursday: Mainly MVFR, with areas IFR possible. Likely SHRA,
Slight chance TSRA.
Thursday Night: Mainly MVFR, with local IFR possible. Slight
chance SHRA, Slight chance TSRA.
Friday: MVFR/IFR conditions possible. Slight chance SHRA, Slight
chance TSRA.
&&
.BTV WATCHES/WARNINGS/ADVISORIES...
VT...None.
NY...None.
&&
$$
WHAT HAS CHANGED...Danzig
DISCUSSION...Myskowski/Danzig
AVIATION...Taber
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