569
FXUS61 KBTV 211916
AFDBTV
Area Forecast Discussion
National Weather Service Burlington VT
316 PM EDT Sun Jun 21 2026
.WHAT HAS CHANGED...
As of 316 PM EDT Sunday...
No significant changes.
&&
.KEY MESSAGES...
As of 316 PM EDT Sunday...
1. Scattered showers and thunderstorms continue this evening,
then dissipate overnight.
2. Steady rainfall for southern Vermont late Monday into Monday
night.
3. An approaching cold front will bring a sharp increase in
shower and thunderstorm chances for the end of the week with
unsettled conditions continuing into the weekend.
&&
.DISCUSSION...
As of 316 PM EDT Sunday...
KEY MESSAGE 1: The overall weather pattern today into this evening
remains little changed with scattered showers and some embedded
thunderstorms continuing. These unsettled conditions are driven by
continued cyclonic flow over eastern Canada and New England, with
multiple upper low centers sending numerous shortwaves through our
forecast area. Breaks in morning cloud cover have allowed 600-1200
J/kg of SBCAPE to develop as per latest RAP analysis. The building
instability has supported the development of showers and
thunderstorms, though weak bulk shear will keep any storms sub-
severe. The Storm Prediction Center once again accordingly has our
area just outlined within the General Thunder contour.
We continue to keep a close eye on hydrological conditions given
fully or near saturated soils and higher flows on rivers, but at
this point no flooding is anticipated. The overall environment (PW
values just over 1 inch, warm cloud depths under 8kft...) does not
support concerning rainfall rates, though we still can`t rule out
training of showers or storms over one area. If any showers/storms
do end up training , we could see localized ponding in poor drainage
areas. So far, rainfall rates have been generally under a quarter
inch per hour, which poses no concerns, but we will be monitoring
observed rainfall amounts closely.
KEY MESSAGE 2: Monday and Monday night is a tricky precipitation
forecast with models still struggling to precisely converge on an
exact storm track. The shortwave responsible for Monday`s
precipitation is currently visible on water vapor satellite imagery
moving eastward over the Midwest. Of particular note on the
satellite loop is the deep moisture associated with the system, with
a direct Gulf connection feeding a 2+ inch PWat air mass toward the
wave. As the system moves eastward over the next 24 hours, the
general concensus is that the surface low will slide eastward to our
south, though just how far north the low and the associated warm
front (and moisture plume) track will dictate what portions of our
forecast area receive the most precipitation. The deterministic GFS
and ECMWF continue to keep the brunt of the rainfall to our south,
but the NAM and CMC have generally been tracking the system further
north... which would bring a swath of heavier rain to our forecast
area. However, the latest deterministic run of the NAM (21.12Z) has
notably shifted southward, and our forecast reflects a blend of this
solution as well as the more consistent ECMWF and GFS. Our forecast
keeps the higher PoPs (70+%) restricted to the southern Adirondacks
and southern Vermont Monday afternoon/Monday evening, and then in
eastern Vermont Monday night.
With regards to impacts as the system rolls through, the ingredients
for moderate to heavy rain will be present...most likely over
southern Vermont. However, we continue to monitor the potential
that this placement may shift, and we can`t discount some of the
higher resolution models that maintain a swath of heavier precip as
far north as central Vermont. As the previously mentioned moisture
plume moves at least as far north as our southern counties,
precipitable water values will climb towards 1.5 inches and warm
cloud depths over 11kft. This will support heavier rainfall rates
than what we have seen over the past few days, but the good news is
that the system should be progressing eastward fast enough to
preclude widespread hydro concerns. In addition, our southern
counties (where the likliest heaviest precip will be) have seen less
precipitation recently than areas further north, thus are better
able to absorb the incoming rainfall.
Rain will taper off from west to east Monday night, and outside of a
few residual showers, the remainder of Tuesday should be mainly dry.
Wednesday will be mainly dry with some breezy northwesterly winds
around 15 mph.
KEY MESSAGE 3: Models are becoming increasingly bimodal in terms of
timing for the end of week system. Blended guidance continues to
bring increasing chances of showers and thunderstorms as flow tilts
southwesterly and as diffluence aloft increases Thursday. However,
an increasing number of deterministic models are pointing to a more
delayed approach suggesting Thursday night and Friday will be the
more active periods. Should the original consensus bear out,
Thursday could feature some thunderstorms with temperatures being
relatively warm in the upper 70s to low 80s. This could point to
potential for a few stronger storms and possibly localized heavy
rainfall. On the flip side, deterministic models keep temperatures warm
for thursday, but drier, while Friday will be the focus for some
early day thunderstorm chances. This timing would point more towards
weaker thunderstorms, but not eliminate heavy rain potential.
Looking at model output, flow may align more with the boundary
orientation favoring a training shower/storm environment. We`ll be
keeping an eye on this pattern through the week given recent
saturation of soils and increased runoff potential. Otherwise,
cyclonic flow will likely linger behind the system keeping some
shower chances in place over at least a portion of the weekend
depending on how fast ridging can build back in.
&&
.AVIATION /19Z SUNDAY THROUGH FRIDAY/...
Through 18Z Monday...Any lingering IFR ceilings at SLK/MSS will
lift in the next 1 to 2 hours per latest satellite trends and
surface observations. Additional scattered showers with embedded
rumbles of thunder are possible again today across our taf
sites, with brief MVFR cigs/vis in the heavier activity.
Greatest potential will be between now and 20z today and have
utilized PROB30 groups to cover in tafs attm. Light terrain
driven winds less than 5 knots become southwest to northwest at
4 to 8 knots by 15z, before becoming light and variable again
around sunset. Sounding data suggest a little more clearing
tonight with developing sharp/shallow inversion, which could
result in fog/br development with IFR or lower conditions at
EFK/SLK and MPV. Given low confidence and time frame have shown
3sm BR with BCFG SCT002 for now. As confidence increases or
decreases in potential fog development, this can be adjusted in
later packages.
Outlook...
Monday Night: Mainly VFR, with local IFR possible. Chance SHRA.
Tuesday: Mainly VFR, with areas MVFR possible. Slight chance
SHRA.
Tuesday Night: VFR. NO SIG WX.
Wednesday: VFR. NO SIG WX.
Wednesday Night: VFR. NO SIG WX.
Thursday: VFR. Chance SHRA, Slight chance TSRA.
Thursday Night: Mainly VFR, with local MVFR possible. Likely
SHRA, Chance TSRA.
Friday: Mainly MVFR, with areas IFR possible. Likely SHRA, Chance
TSRA.
&&
.BTV WATCHES/WARNINGS/ADVISORIES...
VT...None.
NY...None.
&&
$$
WHAT HAS CHANGED...Duell
DISCUSSION...Boyd/Duell
AVIATION...Boyd
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