507
FXUS61 KBTV 221812
AFDBTV
Area Forecast Discussion
National Weather Service Burlington VT
212 PM EDT Mon Jul 22 2024
.SYNOPSIS...
We`ve got a nice late July day on tap today with highs in the upper
70s to mid 80s. Rain showers will move into southern Vermont tonight
with periods of showers and thunderstorms continuing through
Thursday. Thereafter, high pressure will build across the North
Country Friday and into the weekend allowing for a return of dry
weather with temperatures warming to near 90s degrees in the valleys
by Sunday.
&&
.NEAR TERM /THROUGH TUESDAY/...
As of 212 PM EDT Monday...Adjusted a few items, but no big
changes needed for the early afternoon update. Based on radar
and satellite trends, brought in a slight chance thunderstorms
into much of northern New York and southern Vermont sooner, as
early as the next hour in far southern portions of our northern
New York counties. The combination of moisture advection from
the south and differential heating is supporting some agitated
cumulus, with more to our west and south, which will tend to
converge in our region through the afternoon. Limiting factors
include a lot of dry air still in place and meager mixed layer
CAPE. Greatest instability is in the vicinity of the immediate
St. Lawrence Valley where showers are beginning to develop on
the Canadian side.
Previous Discussion...Fog has begun to develop in the favored
valleys across northern New York and Vermont this morning and will
likely persist through around 8 AM. Afterwards, we`ve got another
great late July day on tap with mostly sunny skies allowing
temperatures to warm into the upper 70s to mid 80s with comfortable
dewpoints in the mid 50s. However, a bit of a pattern change is
expected this evening as a warm front begins to lift northward and
brings back rain chances back to the region in addition to
increasing humidity. Rainfall amounts tonight will be rather
lackluster with most locations seeing a tenth of an inch or less
although a few locations could see upwards of a quarter of an inch.
Tuesday is beginning to look a little bit more impressive on the
convective side. The latest CAMs are showing a bit more convection
firing in the warm sector south of the warm front. Model soundings
are supporting of upwards of 750-1000 J/kg of SBCAPE with 25-30
knots of deep layer shear. This is expected to allow for more
widespread convection of which a few storms become structurally
organized and produce period of heavy rainfall. The threat for
severe storms is very low given the storms will be firing in a
"junky" warm sector but a few gusts to 40 mph cannot be ruled out
locally as storms begin to collapse. Rainfall amounts on Tuesday
should be a half of an inch or less but very localized amounts in
excess of 1 inch cannot be ruled out given the latest data showing
increasing convective potential. Still, flooding seems unlikely at
this time as flash flood guidance shows we will need around 2 inches
in one hour, 2-2.5 inches in 3 hours, or 3 inches in 6 hours to
create flooding. However, this rainfall could help prime an
increasing flood threat as we head into later in the week. More on
this below.
&&
.SHORT TERM /TUESDAY NIGHT THROUGH WEDNESDAY NIGHT/...
As of 404 AM EDT Monday...After a day of showers and thunderstorms,
coverage will gradually diminish heading into Tuesday night with the
loss of diurnal heating. Temperatures will be quite mild, with lows
in the upper 50s and 60s.
Additional showers and thunderstorms are expected for Wednesday as
an upper level trough over the Great Lakes pushes eastward. Despite
PWAT values near or exceeding 1.5 inches, there is very limited
instability across the region which will limit precipitation rates
and the potential for heavy rainfall. Temperatures during the day on
Wednesday will be fairly seasonable, with high temperatures in the
upper 70s to low 80s. Dewpoints will be in the 60s, which will feel
quite muggy. Overnight lows Wednesday night will once again be on
the warm side, with temperatures in the 60s in most locations.
&&
.LONG TERM /THURSDAY THROUGH MONDAY/...
As of 404 AM EDT Monday...The active period of weather will continue
as we head into Thursday, with more rounds of showers and
thunderstorms expected. Thursday looks to be more favorable for
developing convection with moderate CAPE values and decent shear
through the afternoon. The primary threat within any storms would be
heavy rainfall, given high PWAT values as well tall and skinny CAPE
profiles. With continued chances for showers each day, WPC has the
forecast area in a Marginal Excessive Rainfall Outlook (ERO) for
Thursday, although the main threat will be in any locations that
receive multiple rounds of showers and heavier rainfall so this will
have to be monitored throughout the week. A few additional showers
will be possible during the day on Friday as the upper level
shortwave departs the region, although they will likely be isolated
in nature. Temperatures will be in the upper 70s to low 80s, with
overnight lows generally in the 60s.
Heading into the weekend, a period of drier and seasonable weather
looks to return as high pressure builds into the region, bringing
some mostly sunny skies as well. Temperatures will increase through
the weekend under strong ridging, with some locations warming into
the upper 80s.
&&
.AVIATION /18Z MONDAY THROUGH SATURDAY/...
Through 18Z Tuesday...VFR conditions will continue for at least
the next 12 hours. All sites will see periods of rain showers,
with a low chance of thunder, resulting in some visibility
reductions mainly between 09Z and 15Z. The greatest chances for
brief IFR visibilities appears to be at RUT, MPV, and BTV at
this time. With some easterly low level developing during this
period MPV will also be more likely to see MVFR ceilings. Winds,
following some 5 to 10 knot southerly and southeast at BTV and
PBG, respectively and under 5 knots elsewhere, will trend light
and variable by 00Z and persist through the remainder of the
period.
Outlook...
Tuesday Night: Mainly VFR, with local MVFR possible. Chance SHRA,
Slight chance TSRA.
Wednesday: Mainly VFR, with areas MVFR possible. Chance SHRA,
Slight chance TSRA.
Wednesday Night: MVFR/IFR conditions possible. Chance SHRA,
Slight chance TSRA.
Thursday: Mainly VFR, with local IFR possible. Definite SHRA,
Slight chance TSRA.
Thursday Night: Mainly VFR, with local IFR possible. Chance SHRA,
Slight chance TSRA.
Friday: Mainly VFR, with local MVFR possible. Chance SHRA.
Friday Night: VFR. NO SIG WX.
Saturday: VFR. NO SIG WX.
&&
.BTV WATCHES/WARNINGS/ADVISORIES...
VT...None.
NY...None.
&&
$$
SYNOPSIS...Clay
NEAR TERM...Clay/Kutikoff
SHORT TERM...Kremer
LONG TERM...Kremer
AVIATION...Clay/Kutikoff
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