290
FXUS61 KBTV 281945
AFDBTV
Area Forecast Discussion
National Weather Service Burlington VT
345 PM EDT Wed May 28 2025
.SYNOPSIS...
Conditions shift from being dry with warmer than average
temperatures back to cooler weather with ample clouds and
periods of rain tomorrow through the weekend. Our impressive
streak of wet Saturdays will continue with moderate rainfall
totals expected. High pressure and dry conditions return next
week with potential for highs warming well into the 80s.
&&
.NEAR TERM /THROUGH THURSDAY NIGHT/...
As of 331 PM EDT Wednesday...Surface high pressure will shift
east this evening allowing for passage of an occluded front
attached to a decaying low peeling northwestward and to a weakly
developing low at a triple point that will track into the
baroclinic zone off the New England coast. With the barotropic
feature likely becoming absorbs into the larger upper
circulation over James Bay and lack of mid/upper level support
for the southern stream energy, the occluded front will be
washing out as it moves through. This will keep QPF on the
lower end, generally less than 0.25", representing a decreasing
trend from the last forecast. More notably, the high
temperatures for Thursday will cool markedly from today into the
upper 60s/low 70s. Overnight lows tonight and tomorrow night
will remain relatively mild with cloud cover and increasing
moisture keeping cooling at bay; lows will generally be in the
40s and low 50s tonight with upper 40s to mid 50s Thursday
night.
&&
.SHORT TERM /FRIDAY THROUGH FRIDAY NIGHT/...
As of 331 PM EDT Wednesday...Fairly uneventful weather is expected on
Friday despite being in a pre-frontal airmass with seasonable heat
and humidity on south/southwesterly flow. It appears there will be
no forcing mechanism to produce organized showers, and we would need
to see a little more surface moisture and cooler mid-level air to
get vertical development over the higher terrain. A subtle trough
sliding eastward across our region could be enough to spark showers,
but generally do not expect thunderstorms, and even showers look
isolated in coverage. The latest CAM output (FV3, NAM3, largely is
consistent with the idea of low chances of light showers during the
day. Chances are slightly higher chances in northern Vermont
relative to the rest of the region, but the day should generally be
dry areawide. Temperatures will warm into the low to mid 70s in most
locations.
Cloud cover should increase greatly Friday night ahead both an
incoming cold front from the west and coastal storm approaching from
the south. Rain chances likewise will increase, with more details
provided in the Long Term section of the discussion below.
&&
.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
As of 331 PM EDT Wednesday...Focus of this period is on our next in a
series of weekend rainstorms. Meteorologically there are
interesting, critical differences with this system compared to the
nor`easter from last week. In addition to the duration being shorter
for rainfall with faster movement, this event will involve a cold
front washing out as it arrives from the west and simultaneously a
coastal storm developing and intensifying to our south in response
to good thermodynamics. With a narrower cloud shield and sharper
upper level system rather than a broad one as we had last week,
there may be some sunshine in western portions of the region.
Meanwhile, frontogenetically-forced moderate to heavy rainfall rates
will be possible in a north-south axis during the day Saturday,
generally from the Champlain Valley and points east. Thankfully the
period of heavier rain should be brief enough, and without
convective intense/torrential rain, to preclude significant impacts.
Some poor drainage flooding in the heaviest footprints could occur,
consistent with the heavy rain WPC hazard outlook, which could be in
the range of 0.75" to 1.5" for much of the Adirondacks and Vermont
in the wetter scenarios based on the 90th percentile of blended
guidance. Taking an average, storm totals would average close to 1"
in most of Vermont, tapering off to about 0.5-0.75" in the
Adirondacks and far northwestern Vermont, and less than a third of
an inch in the the St. Lawrence Valley. Given uncertainties in storm
track, please monitor the forecast for updates as the actual
rainfall forecasts will likely shift.
Continuing from the previous model cycle, the GFS and NAM continue
to show a storm track on the western envelope of ensembles, which
shows an average path near Massachusetts northeastward into New
Hampshire and northern Maine, on Saturday. The western
scenarios would put the heavier rainfall area farther west than
the official forecast or the EMCWF Extreme Forecast Index QPF;
hence the WPC excessive rainfall outlook indicates even the
Adirondacks region could see heavy rainfall. It appears the cold
front will push far enough east ahead of the storm to bring
sharp cooling to at least northern New York and Champlain Valley
Saturday morning as winds turn out of the northwest, resulting
in possible west to east temperature differences Saturday
afternoon. If a western track scenario plays out, there could be
enough pre-frontal instability to see an isolated thunderstorm
in southern/eastern portions of Vermont embedded in the rain,
but for now have left mention out of the forecast. As steadier
rain arrives in these areas and ends in northern New York, the
temperature pattern may reverse by late in the day. Temperatures
generally will be in the 50s as the rain falls and up into the
low 60s ahead of the rain in some valley locations in Vermont.
Based on average ensemble rainfall forecasts, the bulk of the rain
will wind down Saturday night. This is consistent with PoPs quickly
diminishing into the chance range after 00Z/8 PM areawide Saturday.
By Sunday morning, we`ll see the influence of a lagging upper level
trough as its axis moves across our area. The typical associated
height falls in combination with lingering low level moisture will
support scattered to numerous showers, so Sunday unfortunately will
also be wet for most locations, albeit there will be plenty of dry
weather in between showers. With the cold pool overhead,
temperatures will still be well below normal; high temperatures are
even less likely to reach 60 than on Saturday in most locations.
Troughiness lingers over the region on Monday, but upper level
heights should begin to rise as a highly amplified ridge builds to
our west. This pattern should lead to another drier period with no
hazardous weather through at least midweek. The least certain
temperature forecast in the long range is Tuesday, as we transition
into a seasonably warm period not unlike what we saw in mid-May for
that one summer-like stretch. Changes in teleconnections, such as
the Pacific Decadal Oscillation flipping from positive to strongly
negative, will support troughing out west and ridging in the eastern
US, with strong signals for above normal temperatures supporting
daily temperatures into the 80s by Wednesday along with seasonably
humid conditions.
&&
.AVIATION /20Z WEDNESDAY THROUGH MONDAY/...
Through 18Z Thursday...Fair weather cumulus development is
fairly extensive despite ridging over the North Country. A few
elements may become thick enough over higher terrain to squeeze
out a few showers, but terminal locations should remain dry.
Lake breeze has set up and is keeping westerly winds at BTV with
southeasterly flow at PBG. This will continue until 22Z when the
thermal curve begins to cut off this induced wind relinquishing
control back to a light south/southwesterly gradient flow.
Clouds increase sharply overnight with precipitation chances
rising 10-18Z from southwest to northeast. RUT/MPV/SLK will be
at most risk to develop MVFR CIGs after 12Z with lower chances
at IFR.
Outlook...
Thursday Night: Mainly VFR, with local MVFR possible. Chance
SHRA.
Friday: Mainly VFR, with local MVFR possible. Chance SHRA.
Friday Night: VFR. Chance RA.
Saturday: Mainly MVFR, with local IFR possible. Definite RA.
Saturday Night: Mainly MVFR, with areas VFR possible. Chance
SHRA.
Sunday: Mainly MVFR, with areas VFR possible. Chance SHRA.
Sunday Night: Mainly VFR, with local MVFR possible. NO SIG WX.
Monday: VFR. NO SIG WX.
&&
.BTV WATCHES/WARNINGS/ADVISORIES...
VT...None.
NY...None.
&&
$$
SYNOPSIS...Boyd
NEAR TERM...Boyd
SHORT TERM...Kutikoff
LONG TERM...Kutikoff
AVIATION...Boyd
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