900
FXUS61 KBTV 050559
AFDBTV

Area Forecast Discussion
National Weather Service Burlington VT
159 AM EDT Sat Oct 5 2024

.SYNOPSIS...
A line of showers will quickly move across the North Country
from late this evening into the early morning hours on Saturday.
Rainfall will generally be near two tenths of an inch or less,
while temperatures cool back into the lower 40s to lower 50s.
Cooler and drier weather is on tap for Saturday, before another
cold front produces more showers late Sunday into Monday.

&&

.NEAR TERM /THROUGH SUNDAY/...
As of 159 AM EDT Saturday...Line of showers is rapidly pushing
across eastern Vermont at this hour, with some upslope shower
activity lingering behind. Overall the forecast played out very
well with the timing and amounts, with a lot of 0.05" to 0.3"
totals so far. It looks like we had a pretty sharp north/south
gradient of rainfall. Lighter rain rates in the southern half
of Vermont and southern Essex County, New York, were observed compared
to areas to the north based on various surface observations.
Mesoscale analysis showed steeper low level lapse rates and
greater precipitable water as you went northward, likely causing
this difference. Moving forward, have added in areas of patchy
fog to primarily southern St. Lawrence County where partial
clearing and light winds is supporting its development. As
previously indicated, fog in the vicinity of the mountains is
unlikely with plenty of flow; westerly winds aloft are 20 to 25
MPH at the Whiteface Mountain Observatory early this morning and
generally look to stay around that level through the overnight.

Previous discussion...Water vapor shows mid/upper lvl trof acrs
the central Great Lakes this aftn, while narrow ribbon of mid
lvl moisture associated with frontal boundary is approaching the
SLV. This axis of moisture, along with synoptic scale ascent
from short wave energy and right rear quad of 250mb jet wl
produce a narrow axis of showers from west to east acrs our fa.
This axis of precip is expected to expand in areal coverage as
better dynamics arrive with trof after 00z this evening and
spreads into the CPV around 03z, before exiting eastern VT/NEK
by 07z Sat morning. Given the lack of deep layer moisture and
quick forward movement of boundary, thinking qpf generally btwn
0.10 and 0.20 of an inch, with lighter amounts in SLV and
southern VT zns. The probability of fog is <10% tonight, due to
winds/clouds and advection of drier air on northwest flow behind
boundary. Lows range from near 40F SLK to lower 50s CPV.

For Saturday, a few morning sprinkles are possible over the NEK from
leftover moisture and lingering s/w energy, but trends wl be for
clearing skies by aftn. Deep dry layer quickly expands acrs our cwa
on Sat aftn into Sat night with mostly clear skies anticipated. This
wl support areas of fog on Saturday night as winds become light and
variable with building sfc high pres. Sat night looks to be the
coolest of the fall season so far with lows upper 20s SLK, lower 30s
NEK, mid/upper 30s central VT/SLV and low/mid 40s near Lake
Champlain.

&&

.SHORT TERM /SUNDAY NIGHT/...
As of 341 PM EDT Friday...A potent cold front passes through Sunday
night, ushering in a late fall type pattern. Dry weather should
prevail during the day on Sunday, but clouds will increase as they
day goes on. Temperatures will reach the mid 60s to around 70 for
one last day. The cold front looks to reach northern New York in the
evening and Vermont later in the night. The front will have decent
dynamics, but it will move through relatively quickly and it will
not have much of a connection to gulf moisture, so precipitation
totals will not be overly high. There also does not look to be
enough instability for thunder. Currently thinking up to a third of
an inch of rain. A narrow low-level jet will pass overhead out
ahead of the frontal passage and it will bring a brief period of
gusty southerly winds. The jet will bring 30-40 kts down to
around 2000 ft. The extent that these winds will be able to mix
down to the surface remains in question, but gusts of 25-30 kts
look possible on the lake and 20-25 kts in the rest of the
Champlain Valley where there will be channeled flow.

&&

.LONG TERM /MONDAY THROUGH FRIDAY/...
As of 341 PM EDT Friday...A slow-moving upper level low will be
centered over Quebec during much of this time, and several
shortwaves will pivot around it and through the region. There will
be moist cyclonic flow so this period will be cool and cloudy. There
will be scattered showers as well, particularly in the western-
facing upslope areas. The more organized precipitation will move
through with the passage of the shortwaves, and the most potent one
looks to move through on Wednesday. The highest peaks should fall to
around or below freezing from Tuesday until Friday, so there will be
snow showers up there. Right now, snow levels look to drop to their
lowest on Wednesday morning. They currently look to reach between
2000-3000 ft, but the exact elevation will depend on where the
position of the coldest air aloft will be. It could remain just to
the north where then only the highest peaks would fall below
freezing. The upper level low currently looks to move out for next
weekend, so temperatures should moderate and precipitation chances
will go down.

&&

.AVIATION /06Z SATURDAY THROUGH WEDNESDAY/...
Through 06Z Sunday...Mainly VFR conditions through the period.
Showers are winding down in the EFK/MPV/RUT corridor early in
the period. Ceilings at EFK are MVFR but these low clouds may
scatter. Some indications for fog development at MSS and SLK;
given trends and latest data, have indicated a period of IFR at
SLK around dawn. After 14Z, any remaining CIGs will lift and
scatter as high pressure and dry air settle in. Winds shift
from light/calm to west by 12Z, then north/northwesterly by 18Z.
Between 21Z and 03Z winds will become calm.


Outlook...

Sunday: VFR. Slight chance SHRA.
Sunday Night: Mainly VFR, with local IFR possible. Definite SHRA.
Monday: Mainly MVFR, with local IFR possible. Chance SHRA.
Monday Night: Mainly VFR, with areas MVFR possible. Chance SHRA.
Tuesday: Mainly VFR, with local MVFR possible. Slight chance
SHRA.
Tuesday Night: VFR. Chance SHRA.
Wednesday: VFR. Chance SHRA.

&&

.BTV WATCHES/WARNINGS/ADVISORIES...
VT...None.
NY...None.

&&

$$
SYNOPSIS...Taber
NEAR TERM...Kutikoff/Taber
SHORT TERM...Myskowski
LONG TERM...Myskowski
AVIATION...Boyd/Kutikoff