254
FXUS61 KBTV 041811
AFDBTV

Area Forecast Discussion
National Weather Service Burlington VT
211 PM EDT Tue Jun 4 2024

.SYNOPSIS...
Another very warm day with just a few isolated mountain showers are
possible this afternoon and evening. High temperatures will climb
back into the 80s with a few valley locations approaching 90
degrees. A slightly better chance for scattered showers and
thunderstorms are expected for Wednesday with temperatures in the
80s and slightly higher humidity. A cooler and unsettled weather
pattern develops for Thursday and continues into the upcoming
weekend.

&&

.NEAR TERM /THROUGH WEDNESDAY NIGHT/...
As of 210 PM EDT Tuesday...Forecast largely playing out well so
far with lack of precipitation so far, even with plenty of
cumulus forming in the higher terrain. RAP analysis suggests
that a weak mid-level cap, roughly 10,000 feet elevation, has
been stifling growth. And moving forward, with lack of upper
level forcing, it is hard to envision much further development.
That being said, a couple of showers have managed to develop in
the southern Adirondacks, and as we see further surface heating,
we could see the cap broken towards 4 PM such that showers
trend scattered with equilibrium levels potentially quickly
supporting a pulse thunderstorm. Again, think most coverage will
be in the Adirondacks but a few showers will be possible in
central and eastern Vermont, especially in the southern Greens.

Previous Discussion...
GOES-16 mid level water vapor imagery continues to show
mid/upper lvl ridge axis directly overhead with associated very
dry air aloft, while some high lvl moisture is advancing from
the northern Great Lakes toward our fa this morning. The
forecast challenge today wl be potential for a few isolated
showers/storms to develop acrs the higher trrn btwn 3 PM and 8
PM. The large scale synoptic forcing is very weak with ridge
overhead and moisture is rather minimal, as soundings continue
to show drier air aloft mixing toward the sfc this aftn and
dwpts dropping into the upper 40s to lower 50s. This large
temp/dwpt spread limits the sfc based CAPE values thru 21z today
in the 250-500 J/kg. However, toward evening bl dpwts are
expected to increase from weak llvl moisture advection and less
mixing from aloft, creating pockets of sfc based CAPE values in
the 500-800 J/kg. At the same time a very subtle s/w wl try to
break through ridge and combined with some trrn enhanced
convergence to produce a slight 10-20% of an isolated shower or
two with a few rumbles. Highest probability based on trrn wl be
High Peaks of Essex County and along the Spine of the Green
Mountains, where weak backdoor frnt wl help with convergence.
Once again areal coverage wl be limited and based on expectation
I would not cancel any outdoor activities, just keep an eye to
the sky. I saw BTV hit 86F yesterday and progged 925mb temps are
btwn 21-22C, which supports 89F today at BTV and 85F at MPV and
82F at SLK. NBM 10th percentile for high temp at BTV is 88F,
while the 75th percentile is 91F, indicating the relatively
small spread and high confidence in temps this aftn. For tonight
any lingering showers acrs the trrn should dissipate by 02Z,
but sfc dwpts wl be warmer than previous nights, so anticipate a
tad more humidity and maybe some localized patchy valley fog.
Lows in the l/m 50s SLK/NEK to l/m 60s CPV/SLV.

On Weds, instability and moisture parameters are slightly better,
along with another weak s/w crossing our cwa in the aftn/evening
hours. Latest CAM guidance indicates 2m dwpts climbing into the
upper 50s to lower 60s on Weds, creating CAPE values in the 800-1500
J/kg range, while deep layer shear is <20 knots. Given the weak
flow, storm motions wl be 15 knots or less, so the potential for
slow moving convection acrs the higher trrn wl need to be watched
closely, especially as pw values climb above 1.25". Did note WPC ERO
for day 2 has our cwa in marginal risk, which given recent dry spell
and latest FFG seems a bit aggressive. Did coordinate with them, but
their concern was that several members of the HREF family (ARW and
FV3) were highlighting the dacks for potential localized rainfall in
the 2 to 3 inch range, which approaches 3 hr FFG. For now would like
to see better CAM consensus, especially given recent dry spell
before gaining confidence in any flash flood potential.
Otherwise, I have continued with chc pops btwn 16z-00z Weds for
most of the cwa, with highest values acrs the trrn. Temps are
similar to the previous couple of days with highs mostly btwn
82-88F.

&&

.SHORT TERM /THURSDAY THROUGH THURSDAY NIGHT/...
As of 356 AM EDT Tuesday...A frontal boundary moving across the
region will bring more widespread precipitation and a pattern change
after a long stretch of drier weather. Precipitable water values
will be near 1.5 inches, which is near the 90th percentile of SPC
sounding climatology for Albany NY, which supports the potential for
some locally heavy rainfall. WPC has the region in a Marginal
Excessive Rainfall Outlook (ERO), but given the dry antecedent
conditions no widespread hydrologic concerns are expected. Current
QPF amounts range between 0.5 to 1.0, with some higher amounts
possible across the high terrain and within any thunderstorms. The
fairly progressive nature of the boundary will also help mitigate
any potential impacts. Temperatures during the day on Thursday will
be in the 70s to near 80, although it will feel quite humid with
dewpoints in the low to mid 60s. Overnight low temperatures Thursday
night will be on the warm side, in the 50s to low 60s.

&&

.LONG TERM /FRIDAY THROUGH TUESDAY/...
As of 356 AM EDT Tuesday...A closed upper low centered over the Great
Lakes will continue to meander across the region, bringing a period
of showery and cooler weather through the beginning of next week.
Embedded shortwaves will pinwheel around the low, bringing daily
chances for showers, although no day looks like a complete washout.
Daytime high temperatures will generally be in the 70s, several
degrees cooler than the last few days. Overnight lows will generally
be in the upper 40s to upper 50s, which is near normal for this time
of year.

&&

.AVIATION /18Z TUESDAY THROUGH SUNDAY/...
Through 18Z Wednesday...VFR conditions for the 24 hours will
continue. Light, terrain driven winds have been present today
as expected. Overnight, aside from increasing southerly wind at
BTV to near 10 kts, little will change. A popup shower or two
is possible between 21-00z, and based on development of cumulus
think SLK has highest chances of being impacted where VCSH is
indicated. If a shower or two hits a taf site toward sunset,
given higher dwpts overnight, localized patchy fog is possible.
Confidence of IFR fog remains <10% at any site attm, although
SLK looks slightly more favorable at this time.


Outlook...

Wednesday Night: VFR. Chance SHRA.
Thursday: MVFR/IFR conditions possible. Likely SHRA, Slight
chance TSRA.
Thursday Night: MVFR/IFR conditions possible. Chance SHRA.
Friday: Mainly VFR, with areas MVFR possible. Likely SHRA.
Friday Night: MVFR/IFR conditions possible. Chance SHRA.
Saturday: MVFR/IFR conditions possible. Likely SHRA.
Saturday Night: Mainly MVFR, with local IFR possible. Chance
SHRA.
Sunday: Mainly MVFR, with local VFR possible. Likely SHRA.

&&

.CLIMATE...
Based on the current forecast, daily records are possible over
the next three days at some climate sites.

Record high maximum temperatures are possible today and
tomorrow, primarily at Massena and Montpelier. A record high
minimum temperature may occur at Plattsburgh for those nights.
Record daily precipitation is possible at Massena on Thursday.


Current Record High Temperatures:

June 4:
KMPV: 85/1967

June 5:
KMPV: 85/2021
KMSS: 88/1974


Current Record High Minimum Temperatures:

June 5:
KPBG: 65/1963

June 6:
KPBG: 67/1973


Current Record Precipitation:

June 6:
KMSS: 1.09/1953


&&

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

&&

$$
SYNOPSIS...Taber
NEAR TERM...Kutikoff/Taber
SHORT TERM...Kremer
LONG TERM...Kremer
AVIATION...Kutikoff/Taber
CLIMATE...Kutikoff