447
FXUS61 KBTV 171140
AFDBTV

Area Forecast Discussion
National Weather Service Burlington VT
740 AM EDT Wed Jul 17 2024

.SYNOPSIS...
Another hot day is expected today, especially in Vermont where
temperatures will again be in the mid to upper 80s. Showers and
thunderstorms will develop midday today as a slow moving front
gradually progresses eastward. Some showers may contain heavy
rainfall and some gusty winds, though the threat for severe
weather today is lower than yesterday. Conditions become drier
and cooler from Thursday onward.

&&

.NEAR TERM /THROUGH THURSDAY/...
As of 722 AM EDT Wednesday...Forecast is on track with no major
updates needed. Front is approaching our forecast area from the
west this morning, with a 10 degree dewpoint spread along the
front upstream in southeastern Ontario. Morning SPC analysis
shows 1.7+ inch PW plume extending into our northern NY counties
from the southwest, with observed dewpoints in the upper
60s/low 70s over the Saint Lawrence Valley. Previous discussion
follows...

A southwest/northeast oriented front will slowly move eastward
over our forecast area today. Conditions will start off dry and
warm before showers and thunderstorms develop along the front
midday. Temperatures today will be coolest in the Saint Lawrence
Valley and the northern Adirondacks , where earlier onset of
subtle cold air advection will keep highs in the 70s to around
80. Further east however, temperatures will warm into the 80s
for much of Vermont. Warmest temperatures today will be in the
lower elevations of eastern Windsor and Orange Counties, where
heat indices in the low 90s fall just short of Heat Advisory
criteria. Nonetheless, a hot day is expected for lower
elevations of southeastern Vermont.

Isolated showers with an embedded thunderstorm or two will initially
develop late this morning in the northern Adirondacks/central
Vermont.  As the front works eastward midday, increasing instability
(SBCAPE values in Vermont generally 500 to 1000 J/kg today) will
promote increasing coverage of showers and thunderstorms.  Best 0-6
km bulk shear is slightly displaced to the northwest of the best
instability, however there will be 25 to 35 knots of 0-6 km bulk
shear over central and eastern Vermont.  Steep low-level lapse rates
will allow for gusty winds in any thunderstorms that develop,
although weak mid-level lapse rates and lack of mid-level dry layer
will prevent any widespread wet microburst threat. Much of our
Vermont counties remains in the SPC Marginal Risk for severe weather
today, which looks reasonable, with the better risk (Slight) staying
to our south.  Still expecting some gusty winds in thunderstorms
today, but thinking mostly will remain below severe criteria.

Precipitable water values over central and southern Vermont today
will be in the 1.5 to 2.0 inch range, with deep warm cloud layer
over 12 kft.  With this in mind, have added heavy rain wording to
central and southern Vermont today.  Total QPF amounts today will
range from under 0.1 inch in much of northern NY, to 0.25 to 1.0+
inch in Vermont.  Highest amounts are expected in southern Vermont.
Flash flood risk will thus be highest in southern Vermont, and lower
in central and northern Vermont.  However, given all the recent
rainfall, will be watching precip trends closely today.

Thunderstorms and showers will come to an end tonight, with
generally drier conditions expected Thursday. An upper level
shortwave will move through Thursday, so can`t rule out a brief
light shower or two, but have kept PoPs capped in the 10-20
percent range. Much lower PW values will keep any showers light
in intensity. Highs Thursday will be refreshingly cool for most
areas, with values topping out in the 70s to low 80s. Humidity
levels will also be noticeably lower.

&&

.SHORT TERM /THURSDAY NIGHT THROUGH FRIDAY NIGHT/...
As of 340 AM EDT Wednesday...Pleasant weather is expected for the end
of the work week as high pressure settles over the region. A weak
upper shortwave will cross overhead Thursday night, but with little
in the way of moisture, don`t expect much beyond some passing cloud
cover and perhaps a sprinkle or two. Friday will feature partly to
mostly sunny skies, highs in the mid 70s to mid 80s with comfortable
dew points in the 50s. Both Thursday night and Friday night will see
perfect sleeping weather with low humidity and lows in the 50s to
around 60F. A few of the more sheltered locations in the Adirondacks
and Northeast Kingdom could even drop into the upper 40s.

&&

.LONG TERM /SATURDAY THROUGH TUESDAY/...
As of 340 AM EDT Wednesday...Fairly quiet weather will persist
through the weekend and into early next week. Ridging will gradually
give way to a weak cold front moving southward out of Canada. This
boundary will be fairly moisture starved, but can`t rule out a few
showers as it slowly crosses our region Saturday night and Sunday.
The main impact though will be increased cloud cover and slightly
cooler temperatures on Sunday, especially in northern areas. Dry
weather resumes thereafter, though precipitation chances will
increase on Tuesday as another stronger cold front approaches from
the north while low pressure lifts up into the Northeast CONUS.
Temperatures will remain seasonable through the period, with highs
in the mid 70s to mid 80s and lows in the 50s to around 60F.

&&

.AVIATION /12Z WEDNESDAY THROUGH SUNDAY/...
Through 12Z Thursday...Predominantly VFR conditions are expected
this morning as mid-level clouds stream overhead with a front
gradually settling over the forecast area. A few pockets of MVFR
ceilings will continue over higher terrain through 14Z, but
expecting improvement to widespread VFR ceilings after 14Z.
Showers and thunderstorms will develop between 15Z and 00Z
today, but coverage will be scattered and thus have included
some -SHRA but not TS in the TAFs at this time. Ceilings should
remain mainly VFR even within storms, though visibilities will
drop to the MVFR/IFR range within heavier rain showers/tstorms.
Showers and thunderstorms will come to an end overnight. Some
low status and mist will develop in eastern Vermont tonight
after 06Z. Winds will be generally from the south/southwest
today between 5-10 knots with some afternoon gusts to 15 knots.

Outlook...

Thursday: VFR. Slight chance SHRA.
Thursday Night: VFR. NO SIG WX.
Friday: VFR. NO SIG WX.
Friday Night: VFR. NO SIG WX.
Saturday: VFR. NO SIG WX.
Saturday Night: Mainly VFR, with local MVFR possible. Slight
chance SHRA.
Sunday: VFR. Slight chance SHRA.

&&

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

&&

$$
SYNOPSIS...Duell
NEAR TERM...Duell
SHORT TERM...Hastings
LONG TERM...Hastings
AVIATION...Duell