344
FXUS61 KBTV 301907
AFDBTV
Area Forecast Discussion
National Weather Service Burlington VT
307 PM EDT Mon Mar 30 2026
.WHAT HAS CHANGED...
As of 306 PM EDT Monday...
Winter Weather Advisory issued for far northern New York and Grand
Isle County for freezing rain Tuesday into Wednesday.
&&
.KEY MESSAGES...
As of 306 PM EDT Monday...
1. Round 1 of rain with wintry mix near the international
border Tuesday into Wednesday.
2. Round 2 of Rain with wintry mix near the international
border Thursday into Friday.
3. River rises expected with local lowland field flooding
possible Tuesday into Wednesday.
4. Active and warm weather conditions will likely continue into
the weekend.
&&
.DISCUSSION...
As of 306 PM EDT Monday...
KEY MESSAGE 1: A low pressure system tracks west to east Tuesday into
Wednesday, with a track near the international border. As the low
moves into the region, cold high pressure will be trying to build
down from Canada. The precipitation will begin as rain showers as a
warm front type features pushes into the region late tonight into
tomorrow due to the already warm antecedent airmass. However, as the
high builds down and winds switch to northerly, surface temperatures
will drop to around freezing across the northern Champlain Valley,
St. Lawrence Valley, and far northern Adirondacks. The rain showers
should eventually change to freezing rain showers there. A dry slot
should occur during much of the day tomorrow, but a second round of
rain looks to move through late tomorrow into Wednesday morning. By
this point, temperatures will likely be cold enough for freezing
rain to begin in the aforementioned areas. Currently, up to 0.2
tenths of ice is expected, but this is a very uncertain forecast.
Model guidance is widely split and a high sun angle may prevent
enough cooling during the day for icing to occur. A reasonable high
end solution would probably be 0.2 to 0.4 inches like forecast by
the HRRR or NAM, while a reasonable low end solution is nothing as
forecast by much of the global guidance and couple of the other
CAMs. Overall, QPF totals are expected to be between 0.5 to 1.5
inches with higher totals farther south. Some elevated instability
could cause a few rumbles of thunder and local convective
enhancement of the rainfall, though the majority of that should
remain to the south.
KEY MESSAGE 2: Another storm system makes a run at the region for late
Thursday into Friday, though the trend in storm track to the north
continues. Canadian high pressure will be established on Thursday
and it will provide a cold antecedent airmass for this low pressure
to run into. With the current expected storm track, the
precipitation looks to start as a wintry mix and transition to all
rain. Combined GEFS/EPS/CAN ensemble probabilities of 1 inch or more
of snow generally range between 30-70 percent, 3 are between 5-20
percent and 6 are less than 10 percent. The highest probabilities
are farther northeast. Probabilities of 0.1 inch or more of freezing
rain are between 20-40 percent for the favored locations east of the
Greens and in southern Essex County NY. The caveat here is that with
the warming trend and looking at the new deterministic guidance,
these probabilities will likely continue to come down a bit,
especially with the snow.
KEY MESSAGE 3: Despite a gradual southward shift in the heaviest
precipitation, sharp river rises are still expected Tuesday into
Wednesday and lowland field type flooding remains possible. Overall,
the expected 0.5 to 1.5 inch totals over 36 hours would not cause
much of a threat by themselves, but some elevated instability and
associated rainfall enhancement will likely lead to locally higher
totals. The heaviest rainfall axis looks to set up over central and
southern areas, where local amounts up to around two inches are
possible. However, there will be some notable factors limiting the
flood threat. The first is that the rain looks to come through in
two mostly separate rounds, with almost twelve hours in between,
giving time for rivers to take up the water. The second is that
there will be relatively cool surface temperatures and dew points,
especially where the snowpack remains at the higher elevations. Dew
points only look to reach the upper 30s and low 40s, with maximum
temperatures not much higher. A gradually cooling trend should allow
snowmelt to decline further going into Tuesday night. With that
being said, several rivers look to approach Action Stage and minor
flooding cannot be ruled out in a reasonable worst case scenario.
The river forecast to minor for the East Branch of the Ausable River
in Ausable Forks is on the high side, with ensemble guidance
averaging below that and shadowing effects likely limiting
precipitation as well.
KEY MESSAGE 4: An early season Bermuda High will peak in intensity
Thursday night with only a gradual decay expected. A pair of weather
systems across the western US will send impulses northeastward
before finally tracking across the Northeast over the weekend when
the deep layer ridging starts to decay off the Atlantic. Thursday
night into Friday will feature mixed precipitation and rain trending
scattered during the day. High temperatures will climb into the 50s
to 60s again. The track of low pressure Friday afternoon is somewhat
uncertain, but medium range guidance may be overestimating how far
north a 1005-1010mb surface low can get against a 1037-1040mb high
over Quebec Province. The area of low pressure will bend towards a
more eastward, or east-southeast, track, perhaps overhead. The
farther south it goes, the earlier we see precipitation return. Most
of the available moisture will be in the vicinity of the surface low
and less outside. Some marginal instability of 100-250 J/kg will be
possible , but without better forcing and the presence of dry air,
coverage may be scattered. The low track will also influence the
degree of destabilization possible. Briefly drier conditions will
ensue after the low shifts east Friday night into Saturday. Somewhat
cooler air will try to shuffle back south, but with little success
against the stronger system incoming.
The next system will pack a little more punch. Stronger
southwesterly 850mb flow and more warm, moist air will be present as
the area of stronger high pressure in Quebec Province moves out.
This second surface low will likely track north of Montreal, and
medium range guidance suggests a well-defined front. We`ll see how
much of it may get broken up to terrain shadowing against the faster
850mb flow, but for now, rain showers appear very likely, though the
exact time window will be tacked down later.
&&
.AVIATION /19Z MONDAY THROUGH SATURDAY/...
Through 18Z Tuesday...VFR conditions currently prevail across all
terminals this afternoon, with high clouds streaming into the
region. VFR conditions are expected to continue through most of the
evening. Precipitation will start moving into the region late
tonight into the early morning hours, generally between 06Z and 12Z,
bringing lower ceilings and reduced visibilities to terminals.
Conditions are expected to deteriorate quickly within the
precipitation, with IFR ceilings possible at most terminals by 12Z
or so with rain and mist making for MVFR visibilities around 4SM
through the end of the forecast period. Winds continue to be gusty
from the south this afternoon, but will gradually diminishing
towards 00Z or so, becoming more light and variable throughout the
forecast period. Some LLWS may be possible throughout the forecast
period, especially at KSLK and KRUT tomorrow morning.
Outlook...
Tuesday Night: Mainly IFR, with areas MVFR possible. Definite RA,
Definite SHRA, Likely FZRA, Isolated TSRA.
Wednesday: Mainly MVFR, with local IFR possible. Chance RA,
Slight chance FZRA.
Wednesday Night: Mainly VFR, with local MVFR possible. Chance RA,
Slight chance SN.
Thursday: Mainly MVFR and IFR, with areas VFR possible. Likely
RA, Likely SN.
Thursday Night: MVFR and IFR. Definite RA, Definite FZRA,
Definite SN.
Friday: Mainly MVFR, with local IFR possible. Definite RA.
Friday Night: Mainly MVFR, with areas IFR possible. Chance RA.
Saturday: Mainly MVFR, with areas IFR possible. Chance RA.
&&
.EQUIPMENT...
The Colchester Reef meteorological station is out of service.
This site is not serviced by the NWS. An estimated return to
service is May 1st. Please contact us if you observe winds
significantly deviating from the recreational forecast.
&&
.BTV WATCHES/WARNINGS/ADVISORIES...
VT...Winter Weather Advisory from 5 AM Tuesday to 9 AM EDT
Wednesday for VTZ001.
NY...Winter Weather Advisory from 5 AM Tuesday to 9 AM EDT
Wednesday for NYZ026>028-030-031.
&&
$$
WHAT HAS CHANGED...Myskowski
DISCUSSION...Myskowski/Haynes
AVIATION...Kremer
EQUIPMENT...NWS BTV
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