327
FXUS61 KBTV 030711
AFDBTV
Area Forecast Discussion
National Weather Service Burlington VT
311 AM EDT Sun May 3 2026
.WHAT HAS CHANGED...
As of 242 AM EDT Sunday...
The Frost Advisory for this morning was canceled due to more
extensive cloud cover than expected.
&&
.KEY MESSAGES...
As of 310 AM EDT Sunday...
1. A substantial warming trend and breezy periods will occur
through Tuesday.
2. Showers, with thunderstorms also possible Tuesday afternoon
or evening, will be widespread midweek along a slow moving cold
front.
3. No major impacts or significant weather expected late week
into next weekend, as pattern supports unsettled conditions with
below normal temperatures.
&&
.DISCUSSION...
As of 310 AM EDT Sunday...
KEY MESSAGE 1: After a cloudy start to the day, skies will trend sunny
as a shortwave trough pushes to our east. Behind this feature on
satellite imagery early this morning is a large area of clear skies,
giving confidence in this idea. Associated with the sunshine will be
seasonably deep mixing, at least above 750 millibars during the
afternoon, to support widespread breezy northwest winds in the 25 to
30 MPH range for gusts in central and eastern Vermont, with perhaps
slightly lower values in northern New York and western Vermont where
winds at the top of the mixed layer will tend to be a little lighter.
The first in a series of warm fronts will approach the region
tonight. There will be a potent low level, west-southwest jet tied
to some warm air advection, leading to breezy mountain and lake
conditions overnight. These winds combined with the associated cloud
cover suggest frost/freeze is unlikely. However, the timing and
coverage of rain showers is still somewhat questionable leading to
PoPs around 30-50% at this time. Some of the uncertainty is related
to the amplitude of another shortwave progged to move eastward
through this period. Some guidance dampens its motion such that it
passes well to our north and we don`t see extra large scale lift to
promote more widespread rain. Think at least some light rainfall on
the order of 0.01" to 0.1" will occur where the strongest
frontogenesis slides through, which is favored as one goes farther
north and west. Behind this warm front, deep layer ridging should
lead to return of sunshine and again breezy daytime conditions.
Winds aloft will diminish during the day to reduce risk of stronger
winds mixing to the surface, with perhaps highest gusts above 30 MPH
but under 40 MPH, particularly in the northern Adirondacks. High
temperatures look remarkably normal for this time of year, ranging
from the upper 50s to the mid 60s.
Finally, as we move into Tuesday, we remain on track to see a
seasonably warm air mass become established over the northeastern US
with southwest flow aloft. This pattern should result in breezy
southerly flow, with again nothing particularly strong expected.
Given the green up and/or recent wet conditions, fire weather
concerns are minimal at this time as only wind gusts look to be at
critical levels (relative humidity is unlikely to fall below 30%).
Some of the warmest guidance shows a few spots approaching 80
degrees with 925 millibar temperatures well above the 90th
climatological percentile; if these temperatures reach 17 Celsius
during the afternoon, highs in the mid to upper 70s will be achieved
in valley locations. However, precipitation chances will increase
during the day; more on this is covered in Key Message 2.
KEY MESSAGE 2: A relatively long period of beneficial rain is
increasingly likely from late Tuesday through Wednesday. Some of
this rain could be heavy, although there are no signals for
excessive rainfall with only modest heat and humidity on the warm
side of the thermal boundary. That being said, the latest NBM is
consistent with machine learning hazard guidance showing at
least modest (chance) of thunderstorm activity in the warm
sector of the system in most of Vermont and Adirondack region in
New York. Some guidance shows too little instability to result
in convection; surface based moisture does look modest and will
be a limiting factor. Otherwise, decent ingredients for strong
thunderstorms could line up, including good deep layer shear and
increasing instability during the mid to late afternoon hours.
If CAPE increases into the higher end of the progged 500 to
1000 J/kg range, isolated thunderstorms could be capable of
localized wind damage.
Besides this potential hazard, the rain with this front should
largely be beneficial. Much of the rainfall is still on track
to occur on the cool side of the surface front as it slides
through the region Tuesday night through Wednesday. Blended
guidance currently shows 0.5" to 1" rainfall, and given the
relatively slow movement of the front and the large feed of deep
moisture from both the southeastern Pacific and the western
Gulf, would expect these totals could trend upward closer to
some of the operational deterministic models such as the GFS and
ECMWF, which show more of a 0.75" to 1.5" event total for most
locations. Again, a limiting factor for a more impactful event
looks like limited warmth/low level humidity on the warm side of
the boundary to support heavier rainfall rates.
KEY MESSAGE 3: The long wave pattern for late week into next weekend
supports mid/upper lvl ridge acrs the western CONUS, while trough
prevails over the Great Lakes into the ne CONUS. Still watching
multiple embedded s/w`s and amount of potential northern and
southern stream phasing for eventual track of coastal system Thurs
into Friday. Latest 00z trends have been for less phasing and more
progressive mid/upper lvl flow, which supports a track of the SNE
coast and less potential precip acrs our cwa. However, given
mid/upper lvl trof passage with embedded s/w energy and developing
northwest flow aloft, wl keep us unsettled and cool for Thurs into
the upcoming weekend. Coolest day based on thickness values and
925mb to 850mb thermal profiles looks to be Friday, where temps
struggle to reach the mid/upper 30s summits to upper 40s to mid 50s
warmest valleys. WPC conts with likely pops in the mtns, which looks
reasonable given the upslope flow, caa, and available moisture.
General troughiness prevails next weekend with a slow rebound in temps
anticipated. However, with cool pocket aloft with mid/upper lvl trof
and weak embedded s/w`s producing enough lift/instability, feel
additional isolated/scattered showers are likely. Temps mostly in
the 50s for highs and upper 30s to upper 40s for lows. Given the
lack of strong high pres directly overhead and the potential for
clouds, the probability of widespread frost in areas where the
growing season has started is low attm.
&&
.AVIATION /06Z SUNDAY THROUGH THURSDAY/...
Through 06Z Monday...The near term aviation concern is Ceilings
and potential low stratus clouds developing under a mid level
deck. Current obs show VFR vis/cigs, with sct008 at Rutland,
feel best potential for brief intervals of IFR cigs would be
RUT/SLK btwn 06-10z based on crnt obs. Confidence is too low for
tempo group attm. Otherwise, VFR conditions prevail with light
north/northwest winds 3 to 5 knots, these winds increase 5 to 10
knots with localized gusts up to 15 knots btwn 15z and 20z
today. Winds slowly shift to the southwest by sunset this
evening with VFR conditions prevailing.
Outlook...
Monday: Mainly VFR, with local MVFR possible. Slight chance SHRA.
Monday Night: VFR. NO SIG WX.
Tuesday: VFR. Chance SHRA, Slight chance TSRA.
Tuesday Night: Mainly VFR, with local MVFR possible. Definite
SHRA.
Wednesday: Mainly VFR, with areas IFR possible. Definite SHRA.
Wednesday Night: Mainly VFR, with areas IFR possible. Slight
chance SHRA.
Thursday: VFR. Chance SHRA.
&&
.BTV WATCHES/WARNINGS/ADVISORIES...
VT...None.
NY...None.
&&
$$
WHAT HAS CHANGED...Kutikoff
DISCUSSION...Kutikoff/Taber
AVIATION...Taber
|
