788
FXUS61 KBTV 121420
AFDBTV
Area Forecast Discussion
National Weather Service Burlington VT
1020 AM EDT Mon Oct 12 2026
.WHAT HAS CHANGED...
As of 1010 AM EDT Monday...
Updated the Aviation Discussion to reflect conditions trending
towards prolonged IFR ceilings at most airport terminals through
this afternoon.
&&
.KEY MESSAGES...
As of 313 AM EDT Monday...
1. Periods of rain Tuesday into Tuesday night before drying for
Wednesday and Thursday.
2. A strong low pressure system passes through the St. Lawrence
Valley and will bring widespread rainfall and breezy conditions
Friday into Friday night, followed by a sharp cooldown.
&&
.DISCUSSION...
As of 313 AM EDT Monday...
KEY MESSAGE 1: After a mostly dry but relatively dreary day today, the
next round of rain will make its way into the region for tonight
through tomorrow. A surface low will pass through from west to east,
following a stationary boundary that will be in place ahead of time.
While the low will be quick moving and technically more northern
stream and not have a strong connection to Gulf/Atlantic moisture,
it will include the remnants of Tropical Storm Rachael so there will
be some efficient rainfall with the former tropical moisture. HREF
probabilities of half an inch are between 70-100 percent for
northern areas, dropping to between 50-70 for southern areas.
Probabilities of an inch are between 50-80 percent for northern
areas, dropping to the 10-40 percent range for southern areas.
Overall, it will be a beneficial soaking rain. South of the front,
meager instability will be able to develop. Combined with strong
dynamics from the low, a couple stronger storms are possible,
especially over southern St. Lawrence County. The exact northern
extent will depend on the specific low track. Warm air aloft will
remain on the backside so even though the cold front drops
temperatures significantly, any upslope showers look to remain rain
in the mountains. Conditions trend drier for Wednesday, but under a
classic cyclonic northwest flow cold air advection regime, there
will be some upslope sprinkles and showers but no widespread rain.
Thursday looks dry, seasonably cool and should welcome the return of
the sun for a bit.
KEY MESSAGE 2: An upper level trough and surface low pressure system
will pass through the St Lawrence valley on Friday. Widespread rain
is expected with this system as well as breezy conditions.
Widespread rainfall amounts between 0.5 and one inch appear likely
based on latest NWP consensus, and PoPs for late Friday are in the
70-90% range. After the trailing cold front sweeps through, the
temperatures will be much cooler through the weekend. The 12Z GFS
depicts a particularly deep trough, consistent with previous runs.
The 850mb temperatures on the GFS drop to -7C to -8C by 18Z
Saturday, and then down to -8C to -9C by 18Z Sunday. While it is
worth noting that the GFS tends to have a cold bias in these setups,
the current forecast confidently reflects the potential for below-
normal temperatures based on the broader 12Z NWP model suite. Expect
highs generally in the mid-upper 40s for both Saturday and Sunday,
quite chilly. With a northwesterly flow and sufficient moisture in
place, we cannot rule out upslope/mountain snow showers or flurries
over the weekend, with some minor summit-level accumulations
possible.
&&
.AVIATION /12Z MONDAY THROUGH FRIDAY/...
Through 12Z Tuesday...As of 14Z today. Blocked flow has
prevailed and likely will continue through much of the day with
more prevailing IFR conditions at most terminals than
previously forecasted. Froude number look to remain below 0.5
leading to continued IFR conditions at all terminals outside of
MSS/EFK. Satellite depicts widespread low stratus with a pocket
of clearing in the central New York Champlain Valley due to
downsloping off the Adirondacks. BKN003-BKN009 will continue at
least through 16Z for RUT/MPV and likely BTV which features
greater than 50% IFR cig probabilities through 18Z. IFR
probabilities lower slightly lower at BTV to 30-50% from 18-22Z,
before chances for IFR cigs increase above 50% thereafter into
the overnight period tonight. Have amended a TEMPO for this
period between 18-22Z for slight cig improvements. Elsewhere,
similar conditions are expected with greatest confidence in
persistent IFR through the TAF period at SLK. All in all,
confidence in lower ceilings towards IFR have increased since
the previous 12Z TAF for RUT/MPV/BTV.
Previous discussion...Winds light and variable through this
morning will shift to the NNW after 14z and remain less than 10
kts through the period. More rain moves into our area from the
north overnight tonight, and IFR conditions will be possible
again overnight with models indicating possible low stratus.
Outlook...
Tuesday: Mainly MVFR, with areas IFR possible. Definite SHRA,
Slight chance TSRA.
Tuesday Night: Mainly IFR, with local MVFR possible. Definite
SHRA, Slight chance TSRA.
Wednesday: Mainly MVFR, with areas IFR possible. Slight chance
SHRA.
Wednesday Night: Mainly MVFR, with areas VFR possible. NO SIG WX.
Thursday: Mainly VFR, with local MVFR possible. NO SIG WX.
Thursday Night: VFR. Chance SHRA.
Friday: Mainly MVFR, with local IFR possible. Definite SHRA.
&&
.BTV WATCHES/WARNINGS/ADVISORIES...
VT...None.
NY...None.
&&
$$
WHAT HAS CHANGED...Myskowski
DISCUSSION...Myskowski/Neiles
AVIATION...Neiles
|
