Brattleboro, Vermont 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

700
FXUS61 KALY 041530
AFDALY

AREA FORECAST DISCUSSION
National Weather Service Albany NY
1130 AM EDT Fri Apr 4 2025

.SYNOPSIS...
Dry and mild today before a wet weekend ensues. Expect rain to
overspread the region tomorrow morning with wintry mix in the
higher peaks of the southern Adirondacks and southern Greens.
Rain turns steady at times Saturday night into Sunday morning
before starting to exit. As the front stalls south of I-90,
periods of rain showers linger Sunday night into Monday. Then, a
strong cold front sweeps through on Tuesday resulting in much
below normal temperatures and even some snow showers.

&&

.NEAR TERM /THROUGH TONIGHT/...
Key Message:

- Dry, pleasant day today with seasonably warm temperatures
  before rain showers arrive from west to east towards sunrise.

Discussion:

A nice spring day is shaping up across eastern NY and western
New England today as our boundary remains positions well to our
south and west to northwest winds advect a much drier air mass
into the region and Canadian high pressure builds eastward into
NY. Forecast soundings suggest boundary mixing depends towards
850 hPa this afternoon and given increasing afternoon sun,
agree with the previous forecaster`s thinking that temperatures
will end up on the higher end of the envelope. Most should up in
the upper 50s to low 60s with mid-60s in the mid-Hudson Valley
and NW CT. Dew points will turn dry today in this regime
dropping well into the 20s and we adjusted dew points towards
as well. Westerly winds shift to the northwest this afternoon
and remain a bit gusty reaching up to 25-30mph.

Heading into tonight, upper level ridging and subsidence amplifies
overhead in response to a sfc low and associated warm front
advancing northeastward out of the Ohio Valley. This will
effectively maintain dry conditions through at least the pre-
dawn hours with clouds also remaining thin through at least
Midnight. Light winds and the delay to thicker cloud coverage
will allow temperatures to cool into the 30s to low 40s before
the leading edge of the warm air and moisture advection finally
pushes into eastern NY by 09 - 12 UTC. Similar to the previous
forecast, chance and likely POPs for rain initially arrive in
the western Mohawk Valley, northern/eastern Catskills, and
western/southern Adirondacks during this window while areas to
the east only have chance POPs. The higher peaks of the southern
Adirondacks look to see rain/snow mix or mainly wet snow due to
wet-bulbing effects.

&&

.SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
Key Messages:

- Widespread rainfall begins late tonight with a low to medium
  (20 to 60%) probability of 0.01" of freezing rain at the
  highest elevations of the Southwest Adirondacks and Southern
  Greens through tomorrow morning.

- Periods of rain continue through at least Sunday morning
  before tapering off Sunday afternoon, yielding a weekend total
  of 0.5" to 1" of rainfall regionwide.

Discussion:

By this evening, the aforementioned surface high and upper-level
ridge will slide overhead before beginning their departure to
the east. Clouds will begin to increase ahead of an incoming
surface wave and upper-level shortwave with low temperatures
falling to the 30s and 40s.

Rain will begin to overspread the region late tonight/early
Saturday morning from west to east as the surface wave deepens
into an area of low pressure and warm air advection and
isentropic lift increase ahead of its attendant warm front. Some
wet snow will likely mix in at the higher elevations of the
Southwest Adirondacks and Southern Greens at onset with surface
temperatures at or near freezing and small pockets of dry air
near the surface providing a wetbulb effect. However, as warm
air advection continues to increase, a low to mid-level warm
nose will develop and snow could transition to freezing rain.
There is a bit of uncertainty in this element of the forecast,
however. With the aforementioned high sitting just off to our
east by precipitation onset early Saturday morning, southeast
winds will help to dam cold air up against southeastward-facing
slopes of the Southwest Adirondacks and Southern Greens. While
this seems probable with probabilities of temperatures falling
to 32F or lower ranging from 50 to 90% in these areas, forecast
soundings are not completely in agreement in their depiction of
the depth of the warm nose. Timing wise, the window of potential
freezing rain looks to fall between 6 AM and 10 AM with the
highest probability potentially falling between the hours of 8
AM to 10 AM such that the warm nose has time to grow deep enough
to support this precipitation type. Therefore, to convey the
uncertainty of the forecast, at the highest peaks of the
Southwest Adirondacks and Southern Greens where temperatures
will remain at or just below freezing during this time, input
snow with a slight chance of freezing rain from 6 AM to 8 AM and
snow with a chance of freezing rain from 8 AM to 10 AM.
Advisories may be needed in the near future for portions of
these areas given the 20 to 60% probabilities for at least 0.01"
of ice accretion, but after discussion with neighboring offices,
we decided that there was too much uncertainty to consider their
issuance at this time.

After 10 AM, any lingering mixed precipitation should transition
to plain rain and periods of such, becoming moderate at times,
will continue throughout the day Saturday as the aforementioned
warm front nears the region. High temperatures will be cooler
than today with widespread 40s and upper 30s at higher
elevations. By Saturday night, the primary surface low moves
overhead, allowing the warm front to pass through and rain to
continue as lows will generally be above freezing, ranging
widely from the mid 30s to low 40s. Some wet snowflakes could
mix in at the highest elevations of the Southwest Adirondacks
and Southern Greens where temperatures near freezing but
accumulations will be minimal. Rain continues into Sunday as the
low moves east from overhead and its attendant cold front moves
through the region. Widespread rain will become more scattered
and showery in nature by Sunday afternoon before dry conditions
are reinforced Sunday night. Highs Sunday will range widely from
the 40s to 50s with pockets of upper 30s in the Southwest
Adirondacks before low temperatures fall to the 20s and 30s in
the wake of the departing front.

&&

.LONG TERM /MONDAY THROUGH THURSDAY/...
Key Messages:

- High confidence in below normal temperatures beginning next
Tuesday. 30-60% chance of one inch of snow in mountain areas
Monday night into Tuesday. Winds become strong/gusty on Tuesday.

Discussion:

On Mon, a front will be positioned to our south and east and moving
farther away during the day. A few rain/snow showers could linger
into the morning, but otherwise most of the day looks dry with near
normal temperatures. Mon night into Tue a vigorous upper level
trough approaching from the upper Great Lakes is forecast to become
negatively tilted as it tracks into the lower Great Lakes by early
Tue morning. This will result in rapid cyclogenesis, with guidance
indicating the primary cyclone developing just north of our area and
eventually tracking east into northern New England on Tue. So the
main forcing looks to occur from a trailing cold front, with mainly
scattered valley rain/snow and mountain snow showers. NBM probs
indicate a 30-60% chance of > 1" snow in mountain areas. Some valley
areas could see a dusting. As the cyclone deepens, northwest winds
will become quite gusty on Tue as well. Temperatures will be at
least 10 degrees below normal.

Cold/breezy and dry conditions expected Tue night into Wed, although
winds don`t look quite as strong as the system pulls farther away.
Both high/low temperatures should be around 10 degrees below normal.
High pressure then moves east across the area Wed afternoon into Wed
night bringing continued dry but cool conditions. Some moderation
should occur on Thu, as the high shifts east off the coast and a
warmer southerly flow develops.

&&

.AVIATION /15Z FRIDAY THROUGH TUESDAY/...
Through 12z Saturday...VFR conditions are expected to prevail
through the 24 hour TAF period. BKN mid level clouds will be around
for a few more hours this morning, then just BKN high level cirrus
clouds expected through around 06z-08z. Mid level clouds will then
increase ahead of the next system approaching from the west but
remain at VFR levels. Winds today will become north-northwest later
this morning and increase to 10-15 kt with gusts of 15-25 kt
developing. Winds will gradually subside to less than 5 kt tonight.

Outlook...

Saturday Night: High Operational Impact. Breezy. Definite SHRA...RA.
Sunday: High Operational Impact. Likely SHRA.
Sunday Night: Moderate Operational Impact. Chance of SHRA...SHSN.
Monday: Low Operational Impact. Slight Chance of SHRA...SHSN.
Monday Night: Moderate Operational Impact. Breezy. Chance of SHRA...SHSN.
Tuesday: Moderate Operational Impact. Breezy. Chance of SHSN.
Tuesday Night: Low Operational Impact. Breezy. NO SIG WX.
Wednesday: Low Operational Impact. Breezy. NO SIG WX.

&&

.FIRE WEATHER...
While RH values today are expected to drop to 30- 40% in the
Hudson Valley, wind gusts will generally remain in the 15- 20
mph range or lower, except for around the Capital District where
more frequent gusts to around 20 to 25 mph are possible
this afternoon. Nevertheless, given the limited overlap of
stronger winds and lower RH values, combined with the recent
precipitation, the potential for fire spread today does not look
to be high enough to warrant SPS issuance at this time.
Widespread rain is expected late tonight into the weekend, which
should further mitigate any fire weather concerns through early
next week.

&&

.ALY WATCHES/WARNINGS/ADVISORIES...
CT...None.
NY...None.
MA...None.
VT...None.

&&

$$

SYNOPSIS...Gant/Speciale
NEAR TERM...Speciale
SHORT TERM...Gant
LONG TERM...JPV
AVIATION...JPV
FIRE WEATHER...Gant/Main