187
FXUS61 KBTV 121038
AFDBTV

Area Forecast Discussion
National Weather Service Burlington VT
638 AM EDT Mon Aug 12 2024

.SYNOPSIS...
Scattered showers will develop today, but overall rainfall will be
relatively light and most of the time it will be dry. A couple
thunderstorms are possible in the afternoon. Temperatures will be
below average, but there will be a drying trend toward mid-week and
temperatures will rise to around seasonable levels.

&&

.NEAR TERM /THROUGH TUESDAY/...
As of 633 AM EDT Monday...An area of lake-effect rain showers
has moved into far southern St. lawrence County. They should
move out within the next hour or two before more widespread
showers develop this afternoon. Clouds are prevalent over
northern areas but southern areas are mostly in the clear.
However, clouds will develop there this morning as well.
Overall, the forecast is in good shape so few changes were made.

Previous Discussion...There are only a few lingering showers
left at this point, and mostly dry conditions will prevail for
the rest of the night. Fog has begun to develop in parts of
eastern Vermont and it should spread to many of the favored
valleys. Boundary layer winds and some cloud cover should limit
much fog from forming elsewhere. This morning, southwest flow
will develop and bring some Lake Ontario moisture into North
Country. The region is currently under the influence of an
upper-level low centered to the north over Quebec. A shortwave
will pivot around the low this afternoon and move through the
region. Combined with diurnal heating and decreasing
temperatures aloft, scattered to numerous showers will develop,
particularly over northern areas. There will be a couple
embedded thunderstorms, and with just enough instability, a few
of these could contain small hail. Overall, the instability
should be a bit less than yesterday but the air aloft will be
colder. Temperatures will also be cooler than the past few days,
with highs only reaching the mid 60s to mid 70s. The upper
level low remains in place for tonight into Tuesday, but the
coldest air aloft passes to the east. Combined with a lack of
impactful shortwaves pivoting around it, Tuesday should be
mostly dry. There could be an isolated shower across the higher
terrain but dry air at the mid-levels will try to inhibit
anything from forming and try to keep any rain from reaching the
ground. With more sunshine and a lack of showers, temperatures
will rise to the 70s and low 80s. The humidity will remain low
with dew points in the 50s to around 60 for most areas.

&&

.SHORT TERM /TUESDAY NIGHT THROUGH WEDNESDAY NIGHT/...
As of 345 AM EDT Monday...Synoptic scale pattern shows mid/upper
lvl trof acrs the NE CONUS with building sfc high pres from the
central Great Lakes. The combination of northwest flow aloft and
a weak embedded 700-500mb s/w wl interact with limited moisture
and instability to produce a 15 to 30% probability of
showers/storms on Weds aftn. Greatest potential for measurable
precip looks to be acrs the eastern Dacks into parts of the
central/northern Green mtns of VT. Overall impacts and coverage
wl be minimal given the weak forcing and available moisture. As
sfc high pres builds into our cwa, expect areas of patchy fog
both Tues night and Weds night, especially given recent rainfall
and saturated ground conditions. The areal coverage wl depend
upon clearing and bl winds, but climo favored look most likely
at this time. Lows range from the upper 40s to upper 50s both
Tues/Wed nights with highs mid 70s to lower 80s on Weds aftn
with comfortable humidity values.

&&

.LONG TERM /THURSDAY THROUGH SUNDAY/...
As of 345 AM EDT Monday...Mid/upper lvl trof prevails on Thurs
into Friday and may actually retrograde back to the west on
Thurs, before weak sfc ridge builds for Friday into early
Saturday. Guidance has come into better agreement for additional
showers with embedded storms on Thurs aftn, with greatest
potential acrs northern VT, including the NEK. Have continued
with pops in the 30 to 50% range for now, but given trends a
bump toward likely maybe needed over the NEK on Thurs aftn,
given latest moisture/instability progs. GFS/ECMWF both show a
pocket of sfc based CAPE values in the 800-1200 J/kg with
increasing forcing associated with 5h vort dropping south in the
northerly flow aloft. Have west to east pop gradient, as best
forcing/moisture is located over central/eastern VT, with less
favorable parameters over northern NY, which is closer to
building ridge. Temps look near normal on Thurs/Friday supported
by progged 925mb temps of 18-20C.

Next weekend is looking unsettled as next large scale synoptic
mid/upper lvl trof and associated series of boundaries approach
the NE CONUS. Guidance is still offering some differences in the
timing and magnitude of system, but general idea of unsettled wx
looks likely, especially late Sat into Sunday. Dynamics look
potent associated with abnormally strong cyclonic circulation
and if enough instability can develop, the potential for a few
stronger storms wl need to be watched. Plenty of time to access
the shear/instability parameters this week, but something to
monitor as we head toward next weekend. As southerly flow
develops thru a deep layer by next weekend, expect increasing
humidity values, especially by Sunday, which wl result in muggy
overnight lows. Have highs generally in the mid 70s to mid 80s
with lows upper 50s to mid/upper 60s by next weekend.

&&

.AVIATION /12Z MONDAY THROUGH FRIDAY/...
Through 06Z Tuesday... Most terminals are currently VFR and
they should remain that way for the rest of the night. The
exception is SLK and ceilings there should lower from MVFR to
IFR later in the night. Fog development is unlikely at any of
the terminals tonight. Ceilings will rise during the day today
and everywhere should reach VFR. Scattered showers and a couple
thunderstorms will pass through the region this afternoon and
into the evening. They could briefly lower visibilities to MVFR
or even IFR at any of the terminals. These showers will slowly
dissipate this evening. Winds will generally be southwesterly
tonight and into the morning, before turning northwesterly in
the afternoon after a cold front comes through. LLWS is not a
concern.

Outlook...

Tuesday: VFR. NO SIG WX.
Tuesday Night: VFR. Patchy BR.
Wednesday: VFR. NO SIG WX.
Wednesday Night: VFR. NO SIG WX.
Thursday: VFR. Chance SHRA, Slight chance TSRA.
Thursday Night: VFR. NO SIG WX.
Friday: VFR. Slight chance SHRA.

&&

.BTV WATCHES/WARNINGS/ADVISORIES...
VT...None.
NY...None.

&&

$$
SYNOPSIS...Myskowski
NEAR TERM...Myskowski
SHORT TERM...Taber
LONG TERM...Taber
AVIATION...Myskowski