717
FXUS61 KBTV 031743
AFDBTV
Area Forecast Discussion
National Weather Service Burlington VT
143 PM EDT Sat May 3 2025
.SYNOPSIS...
An unsettled weather pattern is anticipated this weekend with
intervals of showers and thunderstorms. A narrow axis of favorable
conditions for thunderstorms will be present across southern
Vermont this afternoon. The weekend will not be a complete
washout, however, with periods of dry weather also expected.
Highs will be in the upper 50s to mid 60s with lows generally in
the 50s. Little change in our pattern is expected for next week
with occasional showers and slightly below normal temperatures.
&&
.NEAR TERM /THROUGH SUNDAY/...
As of 136 PM EDT Saturday...A cold and damp day conts acrs most
of our cwa this aftn with temps struggling in the upper 40s to
mid 50s, except mid/upper 60s south of Route 4. The threat for
thunder is quickly decreasing this aftn, as best instability has
shifted south of our cwa. Have updated pops/wx grids to match
this thinking, while lowering temps in axis of steady rain from
the High Peaks into central/southern VT thru the rest of this
aftn. Otherwise fcst is in good shape.
Previous discussion...This weekend will be another wet one with
continued periods of showers and thunderstorms. We`ll want to
monitor southern Vermont for the potential of heavy rain and
flooding, but at the moment, concerning conditions look to
remain south of our forecast area. Ensembles are indicating a
10-20% chance of an inch or higher of precipitation in 24 hours
across southern Vermont. We`ll be watching to see if model
trends lift the axis of heavy moisture farther north in the
coming days. We also need to monitor the potential for isolated
strong to severe thunderstorms across southern Vermont this
afternoon.
A surface low pressure wave will ride a frontal boundary up across
southern Vermont today into an air mass with precipitable water
values of 1.00-1.25 inches, which means increasing chances of
precipitation from the west/southwest to the east/northeast
throughout the course of the day. As with yesterday, the best
potential for some rumbles of thunder and highest rain amounts will
be southern Vermont where frontogenetical forcing and instability
coincide. Winds should remain light and variable or slightly out of
the north/northeast for much of the day outside any thunderstorms,
which could be gusty. Rainfall amounts during the day range from
0.05-0.40" with locally higher amounts possible. Highs will range
from the upper 50s to mid 70s.
Additional precipitation is expected tonight as the frontal boundary
stalls near southern Vermont and pwat values remain elevated, with
best shower chances closest to the boundary. Up to 0.10-0.20" of
rainfall is anticipated overnight as winds remain light and
variable. Lows will fall into the 40s for most, with some lower 50s
possible in southern Vermont where cloud cover will be most
widespread. Unsettled weather will continue tomorrow as it appears
the frontal boundary has no intention of moving away from the
region, perhaps even rebounding northwards. Wherever the frontal
boundary decides to stall will be most likely to see more frequent
and more widespread rain showers. An additional 0.05-0.50" is likely
outside of the St. Lawrence Valley, which is forecast to miss out on
much of the heavier rain. Highs are forecast to be in the lower to
mid 60s.
&&
.SHORT TERM /SUNDAY NIGHT THROUGH MONDAY/...
As of 344 AM EDT Saturday...Vermont and northern New York will be
near the boundary of very dry air within a col and an area of mid-
level deformation to the south of the col. A stagnant upper low will
maintain a moisture feed over the Mid-Atlantic up into New England
with a sharp drop off as the warm conveyor belt neatly splits out
from the col. There`s modest spread on the exact location of the
col. Such will impact how much precipitation will be present across
the region. One scenario will be that the feature remains far south
and Monday will feature relatively dry conditions. The other
scenario would be that the boundary is far enough north that showery
conditions continue on Monday as moisture continues to lift north
into the region. Either way, it`ll generally be cloudier and wetter
south, with a higher probability of failing to reach 60 F at 30-70%
while up north is 0- 20% where periods of sun are more forecast.
&&
.LONG TERM /MONDAY NIGHT THROUGH SATURDAY/...
As of 344 AM EDT Saturday...The weather pattern will remain stagnant.
An upper low will continue to spin across the Ohio River Valley on
Tuesday. We`re still somewhat on the periphery of various features
in place. Showers are depicted, but may not be widespread, at least
Monday night into Tuesday morning. However by Tuesday evening into
Wednesday, the upper low will finally begin to translate northeast
as the blocking high breaks down. There is the potential for some
heavy precipitation in southern Vermont and southwards as greater
upper level divergence lines up with deep, subtropical moisture
interacting with cooler temperatures aloft beneath the upper low.
There`s not much instability, but PWATs around 1" with backbuilding
potential noted in meso-beta vectors opposite the deep layer flow
for part of Tuesday afternoon. No particular value is extraordinary,
but it does suggest the potential for sustained moderate to heavy
rain for a brief period Tuesday evening into Wednesday night. We`ll
see how things evolve Sunday into Monday with two back-to-back
events that could yield areas of 2-3" accumulated across the next 5
days/120 hours. NBM probabilities of 72-hr amounts greater than 2"
is about 10-20 percent across southern Vermont for the Monday to
Wednesday time frame. The higher probabilities remain well south,
but we will continue to monitor.
Cool and showery conditions will persist Wednesday into Thursday
while the upper low moves across New England and then gets promptly
replaced by a new one. We`ll monitor that one in the hopes that it
moves far enough east next Saturday to offer our first precipitation
free Saturday. The NBM indicates there`s still a 10-20% chance of
rain, but that`s certainly lower than the climo probability of
precipitation at a 40% chance this point of the year.
&&
.AVIATION /18Z SATURDAY THROUGH THURSDAY/...
Through 18Z Sunday...A very challenging aviation fcst for the
next 6 to 12 hours with changeable conditions anticipated. For
example SLK went from LIFR cigs to VFR in the past 10 minutes,
so expect bouncing cigs/vis conditions at many of our sites this
aftn into the evening hours. Highest probability of IFR
conditions wl be at Rutland associated with block northerly flow
down the Champlain Valley, with intervals of IFR cigs likely at
SLK/MPV and BTV thru this aftn with mostly a mix of VFR/MVFR at
MSS/PBG and EFK. As additional rain redevelops toward midnight
tonight, along with light and variable winds, expect widespread
IFR cigs with potential for LIFR cigs at RUT/SLK and MPV. These
conditions should prevail thru 12z, before slowly lifting on
Sunday to a mix of MVFR/IFR. Given the clouds/precip, thinking
fog is unlikely attm, but some reduction in vis btwn 1-3SM is
possible in -ra/mist overnight.
Outlook...
Sunday Night: Mainly VFR, with local MVFR possible. Chance SHRA.
Monday: Mainly VFR, with local MVFR possible. Chance SHRA.
Monday Night: Mainly VFR, with areas MVFR possible. Chance SHRA.
Tuesday: Mainly VFR, with local IFR possible. Likely SHRA.
Tuesday Night: MVFR/IFR conditions possible. Chance SHRA, Slight
chance TSRA.
Wednesday: Mainly MVFR, with local IFR possible. Likely SHRA,
Slight chance TSRA.
Wednesday Night: Mainly MVFR, with local IFR possible. Chance
SHRA.
Thursday: Mainly MVFR, with areas VFR possible. Chance SHRA.
&&
.BTV WATCHES/WARNINGS/ADVISORIES...
VT...None.
NY...None.
&&
$$
SYNOPSIS...Storm
NEAR TERM...Taber/Storm
SHORT TERM...Haynes
LONG TERM...Haynes
AVIATION...Taber
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