454
FXUS61 KBTV 090207
AFDBTV
Area Forecast Discussion
National Weather Service Burlington VT
1007 PM EDT Thu May 8 2025
.SYNOPSIS...
Widespread rainfall will occur tonight into Saturday as a low moves
up the New England coast. Lower rainfall rates should prevent any
flash flood threat, though some minor river flooding is possible
across parts of central and southern Vermont. After the low exits,
much drier and warmer conditions are expected to start next week.
&&
.NEAR TERM /THROUGH SATURDAY/...
As of 959 PM EDT Thursday...No significant changes were needed
with this update. Still seeing some patchy drizzle/mist here and
there, but a few more robust showers are just starting to
develop over portions of south central VT at this hour. Expect
this activity will continue to gradually expand overnight,
becoming fairly widespread early Thursday morning. Have made
some tweaks to PoPs to match these latest trends, but overall
the forecast remains in good shape and no other changes were
needed.
Previous discussion...Extremely blocked northwest flow has
allowed a low cloud deck to remain entrenched across the region
today. Combined with cold air advection, temperatures have only
risen a few degrees today, an impressively low diurnal range for the
time of year without steady precipitation. Areas of mist and drizzle
will continue this afternoon and they may increase in coverage
tonight as the effects of diurnal heating subside. With the
continued cloud cover and boundary layer flow, temperatures tonight
will only fall about as much as they rose today. A deepening low
will slowly track across southern New England and into the Gulf of
Maine, bringing widespread rainfall from tonight into Saturday. Some
minor flooding is possible in portions of southern and central
Vermont, and see the hydrological discussion at the bottom for more
details. Any elevated instability looks to remain across southern
and coastal New England, so it should only be a long duration of
light to moderate stratiform rain. With steady rain and northeast
flow, temperatures will struggle to move at all on Friday, so highs
should be in the 40s and 50s across the region, though temperatures
will not fall much Friday night. Temperatures look to be just too
warm for any snow to fall on the summits, though the storm is taking
what would be an ideal track in the winter.
&&
.SHORT TERM /SATURDAY NIGHT/...
As of 401 PM EDT Thursday...The North Country will be situated in the
commahead of a deepening coastal storm on Saturday, resulting in
dense cloud cover, cool northwesterly winds, and continued rainfall.
The 12Z model guidance has been largely in excellent agreement on
the storm track, which has boosted confidence in a rainy day. The
additional rain will produce further stream and river rises across
far northeastern New York into Vermont as banded precipitation
produces embedded heavier rainfall of >0.1" per hour amidst light to
moderate intensity rain. The rain will begin to taper off and move
to the east of the area during the afternoon. Additional rainfall
amounts on Saturday most likely will average 0.25" to 0.5", which
has increased by an average of 0.1" from predictions this time
yesterday. It looks like model trends have stabilized with
regards to the progression of the low pressure system, so while
locally heavier rain may be possible, the best frontogenesis and
mid-level lift will translate to the northeast to limit
duration of heavier rain. That said, showers could linger in the
western slopes of the higher terrain in northern Vermont into
the evening with very moist and blocked northwest flow. As
partial sunshine returns during the afternoon in western areas,
and perhaps southern portions of Vermont, temperatures will
rebound a bit into the upper 50s and lower 60s. For those
recreating, note that mountain conditions will be cold and wet
with wind chills only near freezing at summit level.
The low pressure area departing is not expected to be blocked, which
will limit duration of backside winds Saturday night. It looks like
a few hours of gusty northwest winds in the 25 to 30 MPH range is
favored in much of Vermont, especially in central and eastern areas.
Mid-level stability could lead to locally stronger gusts in gap flow
that we`ll monitor. The scattering of clouds and lightening winds
overnight will also allow temperatures to become seasonably chilly.
Forecast lows are in the mid 30s to mid 40s for most locations, with
sharply drier air beginning to work its way in from the northwest.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
As of 421 PM EDT Thursday...No big changes to the previous
forecast highlighting a nice pattern change to warm weather. Dry
conditions are a near lock along with a warming trend Sunday
through Tuesday, with a substantial increase in high
temperatures now strongly favored to exceed 80 degrees in all
valley locations. It may be our warmest day so far this spring.
In contrast, confidence of another very warm day for Wednesday
is lower with a more typically large range in possible high
temperatures. Amongst global ensemble clusters, there are large
differences in the position and strength of an upper level low
that will move towards us and suppress the ridge of high
pressure in place; drier scenarios are ones in which this trough
or closed low remains over the central US. If it opens up and
pushes northeastward, some showers and cloudier weather will
move into our region as soon as Wednesday. Scattered showers,
and possibly some thunderstorms, will become more likely into
Thursday with plenty of seasonable warmth and humidity around.
&&
.AVIATION /02Z FRIDAY THROUGH TUESDAY/...
Through 00Z Saturday...MVFR ceilings current prevail across the
region, with ceilings gradually dropping towards IFR conditions
over the next several hours. Areas of mist and drizzle may lead
some reduced visibilities in addition to the low ceilings. These
low MVFR and IFR ceilings are expected to continue throughout
the forecast period. Precipitation will begin to overspread the
region late tonight, continuing over the next 24 hours with
some periods of moderate to heavy rainfall possible towards the
end of the forecast period, which may bring additional
reductions to visibilities at times. Northerly winds will
generally be light, less than 10 knots.
Outlook...
Friday Night: Mainly MVFR, with areas IFR possible. Definite RA.
Saturday: Mainly MVFR, with areas IFR possible. Chance RA.
Saturday Night: Mainly VFR, with local MVFR possible. NO SIG WX.
Sunday: VFR. NO SIG WX.
Sunday Night: VFR. NO SIG WX.
Monday: VFR. NO SIG WX.
Monday Night: VFR. NO SIG WX.
Tuesday: VFR. NO SIG WX.
&&
.HYDROLOGY...
A long duration rainfall event will occur from tonight into Saturday
evening, with the heaviest rain expected Friday night into the day
on Saturday. There will be a sharp rainfall gradient across the
region, with 1.5 to 3 inches expected from the Adirondacks eastward,
and a few tenths to around 1.5 inches expected across the rest of
northern New York. Overall, this is generally between the 50th and
75th percentiles of the GEFS/EPS/CAN ensemble. The region will
remain on the northwest side of the storm and any elevated
instability is expected to remain to the south. Therefore, with only
stratiform rainfall and PWATs not excessively high, rainfall rates
are expected to be too low to cause any flash flooding. However,
across parts of central and southern Vermont, some minor river
flooding is possible. This is due to the high antecedent streamflows
in those areas combining with the anticipated rainfall. Even still,
the lighter rainfall rates will be a limiting factor on the river
flooding as well. Elsewhere, there will be river rises but they
should remain around and below bankfull.
&&
.BTV WATCHES/WARNINGS/ADVISORIES...
VT...Flood Watch from Friday afternoon through Saturday evening for
VTZ010-011-019>021.
NY...None.
&&
$$
SYNOPSIS...Myskowski
NEAR TERM...Hastings/Myskowski
SHORT TERM...Kutikoff
LONG TERM...Kutikoff
AVIATION...Kremer
HYDROLOGY...Myskowski
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