189
FXUS61 KBTV 232332
AFDBTV

Area Forecast Discussion
National Weather Service Burlington VT
732 PM EDT Tue Jul 23 2024

.SYNOPSIS...
Daily shower chances, with thunderstorm risk peaking Wednesday,
will continue through Thursday. Some thunderstorms may be of the
stronger variety Wednesday afternoon in northern New York. High
pressure will build across the North Country Friday and into
the weekend, allowing for a return of dry weather with
temperatures warming to near 90s degrees in the valleys by
Sunday.

&&

.NEAR TERM /THROUGH WEDNESDAY NIGHT/...
As of 732 PM EDT Tuesday...A quasistationary front is currently
draped across the northern third of our forecast area. Showers,
with embedded downpours have been forming in the vicinity of
the front, roughly along a line stretching from Saranac Lake, NY
to Waterbury, VT. Mesonet sites show rainfall amounts ranging
from 0.5 to 1 inch in the past couple of hours, below the NERFC
1 hour flash flood guidance of 1.2 to 1.6 inches. North of the
front, visible satellite shows partly to mostly sunny skies
along with dry weather across far northern NY and northern VT.
Expect these diurnally driven showers and downpours to wane with
sunset. With low winds and a moist boundary layer, expect areas
of patchy fog to develop, some of which may be locally dense.

PREVIOUS DISCUSSION...Pulse showers, driven by differential
heating and large scale lift south of a quasi- stationary front,
are scattered across southern portions of our northern New York
counties and in an arc across portions of central Vermont where
additional rain is not needed. Thankfully, as expected mid
level height rises have stifled convection to limit growth such
that so far no thunderstorms have developed. A non- zero chance
exists that an updraft can support a taller storm briefly, but
overall rain rates will be limited through tonight. As showers
gradually shift south and eastward, they should diminish quickly
after dark as they have been driven by surface instability.
While not explicitly in the forecast, areas of fog may develop
as the front lifts back north of the International Border
tonight and temperatures drop to near the dew point. A mixture
of stratus and fog is more likely along and east of the Green
Mountains as shallow southeasterly wind is expected to develop.

For tomorrow, a marginal (level 1) risk remains in effect for
northern New York from the Storm Prediction Center. An associated
risk of excessive rainfall will be present per the latest
Weather Prediction Center outlook. The forcing for organized
convection has continued to look favorable in our western areas
based on the track of a low pressure center to our west, which
will drag a pre-frontal trough into western New York during the
afternoon. That will be the focus for thunderstorms which should
advance north and eastward into northern New York by late
afternoon. Stronger cells will be capable of damaging wind gusts
and torrential rain, although instances of heavy rainfall should
be isolated with only mediocre ingredients for high rainfall
rates. As always, training of cells would support possible
instances of flash flooding but the risk is low at this time.
Again, while the focus in northern New York, some storms,
especially if this event moves through on the faster side, could
remain strong into the Champlain Valley and possibly farther
east. We`ll continue to watch trends to see if the convective
threat broadens. Highs temperatures and dew points will likely
be a few degrees warmer than today, helping to fuel the storms.

As the associated upper level trough continues tracking eastward
Wednesday night, additional showers will be possible, but with a
much lower thunderstorm potential. With abundant cloud cover and
southerly wind, it will be a mild night especially in the wide
valleys where temperatures will struggle to fall below 70.

&&

.SHORT TERM /THURSDAY THROUGH THURSDAY NIGHT/...
As of 321 PM EDT Tuesday...Thursday has trended drier, with the
flooding threat continuing to trend down. A round of showers passes
through early in the morning associated with a prefrontal trough. It
looks to pass through early enough that diurnal heating will not be
able to destabilize the atmosphere enough to cause any significant
convection. Behind this prefrontal trough, instability will struggle
to develop and PWATs will fall quickly. With fast storm motion as
well, the threat for any flooding is low at this point. While there
will be adequate synoptic lift and deep layer wind shear for strong
storms, unfavorable atmospheric profiles and limited CAPE will keep
the threat of these storms low. However, they cannot be completely
ruled out at this point. This front ushers in a more refreshing
airmass as well. Dew points will fall into the 50s on Thursday and
temperatures Thursday night will fall into the 50s and low 60s.

&&

.LONG TERM /FRIDAY THROUGH TUESDAY/...
As of 321 PM EDT Tuesday...High pressure will remain in control for
much of this period and it will bring a long stretch of dry weather.
After the chance of a very isolated shower across some of the higher
elevations of Vermont on Friday, dry weather should prevail until
late late Monday at the earliest. While temperatures will start out
close to climatological normals on Friday and Saturday, they will
rise well above normal by the beginning of next week. Temperatures
look to make a run at 90 in the broad valleys starting Monday. NBM
probabilities of exceeding 90 in the valleys is generally between
50-70 percent. Humidity will also increase by then and dew points
look to reach the low to mid 60s. The heat and humidity will likely
increase a little more by mid week.

&&

.AVIATION /00Z WEDNESDAY THROUGH SUNDAY/...
Through 18Z Wednesday...At this time all terminals are seeing
VFR conditions as low clouds have scattered out. A few showers
are across the airspace; there are slight chances (mainly
around 20%) of impacting EFK, MPV, and RUT through 00Z, but a
direct hit and reduction in visibility is unlikely. Mostly dry
weather follows overnight with light winds becoming increasingly
out of the south/southeast. Moist low level air will contribute
to chances of MVFR ceilings at all sites, and possibly fog at
times for sites like MPV and EFK. After 12Z any low stratus/fog
will dissipate as flow increases ahead of a low pressure system
to our west. Winds will be 5 to 10 knots, mainly southerly
except easterly at MSS. Towards the end of the period, showers
and thunderstorms will develop in New York mainly south of the
area but may impact SLK by 18Z.

Outlook...

Wednesday Night: Mainly VFR, with local MVFR possible. Chance
SHRA, Slight chance TSRA.
Thursday: VFR. Likely SHRA, Slight chance TSRA.
Thursday Night: Mainly VFR, with areas MVFR possible. Chance
SHRA.
Friday: Mainly VFR, with local MVFR possible. Slight chance SHRA.
Friday Night: VFR. NO SIG WX.
Saturday: VFR. NO SIG WX.
Saturday Night: VFR. NO SIG WX.
Sunday: VFR. NO SIG WX.

&&

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

&&

$$
SYNOPSIS...Kutikoff
NEAR TERM...Chai/Kutikoff
SHORT TERM...Myskowski
LONG TERM...Myskowski
AVIATION...Kutikoff