726
FXUS61 KBTV 132343
AFDBTV
Area Forecast Discussion
National Weather Service Burlington VT
743 PM EDT Mon Apr 13 2026
.WHAT HAS CHANGED...
As of 303 PM EDT Monday...
Removed wind advisory and made minor tweaks to temperatures
and timing of precip through midweek.
&&
.KEY MESSAGES...
As of 303 PM EDT Monday...
1. Showers with embedded thunderstorms are expected on Tuesday
with a couple of stronger storms possible, mainly south of Route 4.
2. Additional rounds of showers and thunderstorms are expected
Wednesday and Thursday as boundary remains draped across our
forecast area.
3. A more amplified weather pattern will lead to mainly dry and
warm conditions early in the weekend, followed by a round of
widespread showers and a sharply cooler period Sunday night into
Monday.
&&
.DISCUSSION...
As of 303 PM EDT Monday...
KEY MESSAGE 1: The forecast challenge is amount of clearing and
associated sfc heating/instability that can develop on Tues. GOES-19
water vapor imagery shows compact s/w energy moving along the
International Border this aftn, while large area of subsidence/dry
air aloft is located over the central Great Lake and approaching
the SLV. As this moves overhead tonight, expect lowering cloud
levels with some patchy fog possible over the northern Dack
Valleys. Lows generally in the mid 40s to mid 50s tonight.
For Tuesday our s/w energy of interest is currently located over
central IA with developing lightning over northern IL/WI. This
energy wl quickly move eastward in the fast 700-500mb flow aloft and
being located over the eastern Great Lakes by 12z Tues. Upstream
satl imagery shows a rather messy warm sector in regards to plenty
of clouds and feel this could influence our sfc heating/instability
acrs our cwa on Tues. Weak sfc low pres is expected to travel along
boundary draped near the International Border on Tues with very warm
925mb to 850mb thermal profiles, but soundings low clouds stuck
under the inversion in the morning and mid/upper lvl convective
debris clouds developing by early aftn, which wl probably limit sfc
heating. HREF shows the greatest potential for sfc based CAPE
profiles >500 J/kg south of a SLK to LEB line of 40 to 60%, with
highest potential mainly south of Route 4. Meanwhile, the
probability of 0 to 6 km shear >50 knots is 80 to 100% near the
International Border, indicating strongest winds are north and best
deep layer instability is south. NAM 12KM/NAM 3KM solutions are the
most aggressive with sfc/mu CAPE values of 1000-1500 J/kg into our
central/southern cwa, while HRRR/WRF NSSL and RAP are <500 J/kg.
This wl become a nowcasting scenario on Tuesday, watching if clouds
can dissipate and timing of boundary crossing our cwa for
determining how robust convection can develop. For now a few
stronger storms are possible mainly Rutland/Windsor counties, but
feel greatest action wl be south of our cwa. The latest SPC day2
outlook continues to place part of our cwa in a Marginal Risk (1 out
of 5). Temps are very challenging on Tues as 925mb temps would
suggest highs well into the mid 70s to lower 80s, but clouds and
precip with sharpening boundary wl have significant impacts on
highs. Have mid 60s SLV to near 80F VSF.
KEY MESSAGE 2: An active pattern is expected for Weds and Thurs as
boundary remains draped acrs our cwa with multiple s/w`s riding in
the westerly flow aloft producing additional chcs for precip.
Boundary position and clouds wl have significant impact on temps and
sfc instability for both Weds/Thurs. Latest trends indicate
additional s/w energy arriving acrs our western cwa by 15z with some
instability possible acrs our central/southern fa. Clouds and precip
wl impact thermal profiles and associated thermal dynamics. Any
stronger/deeper convection wl have the potential to produce
localized heavy downpours, especially with pw values approaching
1.5" or 2 to 3 std above normal on Weds. Similar type temp profile
as Tuesday with greatest probability of mid 70s acrs
Rutland/Windsor counties, with coolest air over the northern
SLV/CPV and parts of the NEK. Little change in the large scale
synoptic pattern is anticipated on Thursday, as additional s/w
dynamics and moisture in the westerly 700 to 500mb flow impacts
our cwa. Additional showers with embedded storms are expected,
with some localized heavy downpours possible. As always, the
instability wl be driving factor on how strong storms can
become, but progged 925mb temps are very warm again with values
in the 14-18C range. If sun develops highs easily in the 70s,
but if clouds prevail with occasional showers, temps mostly hold
in the upper 50s to mid 60s.
KEY MESSAGE 3: The large scale pattern for Friday shows anticyclonic
flow building in while low level temperatures remain well above
normal (still near the 90th percentile for 850 millibar temperatures
during the afternoon). There is some uncertainty in the position of
the incoming ridge and how much northerly flow develops, so
temperatures in northern valleys could trend lower. A scenario with
low level westerly rather than northerly flow will lead to a warmer
day by several degrees (such as a high near 70 rather than low 60s).
Said scenario also would lead to some instability (highest values in
the cluster mean are near or above 500 J/kg). Therefore, the slight
chance of thunder currently indicated in southern portions of
Vermont for Friday afternoon looks reasonable. That being said, with
the ridging expected and lack of a trigger for showers,
precipitation chances should become low from Friday afternoon
through Saturday afternoon. Think the ensemble probabilities of
rain, about 25-50% through this period, are a bit high relative to
forecaster thinking. Probabilities of 0.1" or greater, in the 10 to
15% range for most locations, seems like a better estimate of actual
rain chances.
Widespread showers then are on track to approach the area from the
west late Saturday into Sunday in advance of a well defined cold
front. A primary low pressure system will far to our northwest; some
indications exist that a weak secondary low could develop along the
front. Regardless, a heavy rainfall is not expected with even the
90th percentile 24 hour QPF in ensemble guidance below 1" at this
time. There is only a weak signal for thunderstorms in machine
learning statistical guidance, which would only occur with a slower
frontal timing. Better instability will likely be well to our south
ahead of the front, and most likely timing seems to be lined up more
in the overnight timeframe, limiting potential for surface
instability. Temperatures Sunday are highly uncertain due to
differences in timing of the anticipated cold front and degree of
cooling in its wake. With a slower passage, there is some potential
for warm conditions again, although less likely than on Friday or
Saturday. By Monday a much colder air mass will likely arrive as a
secondary cold front pushes through Sunday night. Any precipitation
could be in the form of elevationally dependent snow showers, as 925
millibar northwesterly flow comes with temperatures plunging below
the 25th percentile at around -1 to -3 Celsius.
&&
.AVIATION /00Z TUESDAY THROUGH SATURDAY/...
Through 00Z Wednesday...A weak trough is approaching the
Champlain Valley with scattered showers and there are mostly
southwest winds 5 to 10 mph, but some variability. Some
visibility reductions and ceilings between 1000-3500 ft agl are
present as well. A sharper trough will shift southeast around
02z-04z. Some lower ceilings will be possible. After 06z, winds
will trend light and variable. Any breaks in cloud could produce
some fog, mainly for KEFK/KSLK/KMPV. At 12-14z, south to
southeast winds, except remaining northeast at KMSS, will
develop. Ceilings should come up, but it will be short lived as
showers shift east between 15z and 00z. There are some timing
differences, and there is also the potential for thunder. Given
the uncertainty, TAFs show SHRA. Some LLWS is also expected as
southwest to west winds at 2000 ft agl increase along the next
batch of precipitation.
Outlook...
Tuesday Night: MVFR/IFR conditions possible. Likely SHRA.
Wednesday: Mainly MVFR, with local IFR possible. Likely SHRA.
Wednesday Night: Mainly MVFR, with local IFR possible. Chance
SHRA.
Thursday: Mainly MVFR, with local IFR possible. Likely SHRA,
Slight chance TSRA.
Thursday Night: MVFR/IFR conditions possible. Chance SHRA, Slight
chance TSRA.
Friday: Mainly MVFR, with local IFR possible. Chance SHRA.
Friday Night: VFR. Slight chance SHRA.
Saturday: Mainly MVFR, with areas VFR possible. NO SIG WX.
&&
.EQUIPMENT...
The Colchester Reef meteorological station is out of service.
This site is not serviced by the NWS. An estimated return to
service is May 1st. Please contact us if you observe winds
significantly deviating from the recreational forecast.
&&
.BTV WATCHES/WARNINGS/ADVISORIES...
VT...None.
NY...None.
&&
$$
WHAT HAS CHANGED...Taber
DISCUSSION...Taber/Kutikoff
AVIATION...Haynes
EQUIPMENT...NWS BTV
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