000
FXUS61 KBTV 271145
AFDBTV

Area Forecast Discussion
National Weather Service Burlington VT
745 AM EDT Sat Apr 27 2024

.SYNOPSIS...
Today will be dry across North Country, although clouds and
southerly winds will be on the increase. Scattered to numerous
rain showers develop overnight tonight into Sunday. Periods of
shower activity with intervals of dry weather are expected for
the upcoming week.

&&

.NEAR TERM /THROUGH SUNDAY/...

As of 740 AM EDT Saturday...Forecast remains largely on track
so only made minor tweaks to the hourly temperatures. Thin high
clouds are just making headway into northern NY per visible
satellite imagery with the precipitation shield still across far
western NY and western PA. Enjoy the blue skies this morning!

PREVIOUS DISCUSSION...1032 mb surface high sags south of Long
Island as a warm front associated with a strong surface low
pressure across Iowa approaches our region from the southwest.
We are starting to see reflectivity returns on the regional
radar mosaic across Lake Erie into the Ohio/Pennsylvania border.
That is associated with an area of 1 to 1.2 inch PWATs. As for
our area, we remain dry with PWAT values of 0.2 inch. Indeed, we
will start the day with mostly clear skies but mid to high
clouds will be moving into North Country from west to east.
Overall, rain should hold off till around sunset so while it is
not going to be a blue bird day like the past couple of days, it
will be quite pleasant for outdoor activities. It will also be
quite breezy, as south winds increase during the day today, with
the strongest winds expected across the St Lawrence valley,
southern Adirondacks and the Champlain valley, where sustained
winds will be around 10 to 15 mph and gusts 20 to 25 mph.
Elsewhere in the sheltered areas across the northern Adirondacks
and east of the Green Mountains, stronger winds should kick in
by the afternoon hours.

Deamplifying shortwave trough embedded within a larger area of upper
ridging crosses our CWA overnight tonight, pushing a warm front
through and advecting a considerably more moist air mass than
we have gotten used to in recent days. Both the GFS and NAM are
in good agreement with a north-south oriented plume of 1 inch
PWATs advecting eastward during the evening into overnight
hours, replacing the 0.3 inch PWATs out ahead of it. To put in
perspective how dramatic that is, we go from the 10th percentile
to the 90th percentile of SPC PWAT sounding climatology for the
Albany, NY upper air site. Why such a dramatic change in air
mass? Zooming out to the CONUS view, the plume of anomalous
PWATs along with a strong low level jet (LLJ) both have origins
in the Gulf of Mexico. An upper level ridge will be situated
across the southern Appalachia, so the nose of the LLJ would be
pointed somewhere across New England, helping to enhance
rainfall rates. The HRRR is by far the most bullish in rainfall
amounts, with locally over 1 inch possible. Not all the CAMs are
that bullish, however, so it is far from certain we get
widespread soaking rain. At this time, we have raised rainfall
amounts into the 0.25 to 0.5 inches range for overnight Saturday
into Sunday. We should get more clarity with the 12z HREF
guidance and if further upward adjustment to rainfall amounts is
necessary. In addition, the exact orientation of the H5 ridge
could determine if the heavy rain falls over Vermont or New
Hampshire. Either way, there are no hydrologic or flooding
concerns.

A 1002 mb surface low pressure tracks northeast from the southern
tip of Hudson Bay to Nunavut Sunday morning. As it does so, it will
be weakening but has just enough dynamics to drag a weak cold front
across the northern Adirondacks and northern Vermont. Accordingly,
these areas have the best chance for most widespread coverage of
convective showers and higher rainfall amounts. Forecast soundings
indicate some steep mid-level lapse rates and elevated instability
overnight Saturday, so a few nighttime rumbles of thunder are not
out of the question particularly across northern NY. After a brief
lull It is worth noting that dew points on Sunday will rise into
the 50s to even near 60, especially across the St Lawrence Valley
and west of the Adirondacks in northern NY. As for Vermont, we start
out Sunday with dew points in the 40s but 50s dew points will also
overspread the state by mid day into the afternoon hours. This would
result in a few hundred joules of CAPE, so a few rumbles of thunder
are not out of the question mainly across our northern zones. With a
bit of sunshine, temperatures are expected to rise into the mid 60s
to low 70s. That being said, areas across northern Vermont that has
the most widespread rain coverage could see cooler daytime
temperature readings. However, we are also in late April so the high
sun angle will allow temperatures to warm rather efficiently. As for
outdoor activities on Sunday, while there would likely be rain drops
to dodge, it would not be exactly a washout either. If anything, the
rainfall would be beneficial in this pre green-up environment and
help keep the fire danger at bay. For warm weather and summer
lovers, the uptick in humidity and possible rumbles of thunder would
serve as a reminder that summer is not too far away. Overall
temperatures will be on the slightly warmer than normal with highs
on Sunday in the mid 60s to low 70s, except cooler across the
Adirondacks and northeast Vermont.

&&

.SHORT TERM /SUNDAY NIGHT THROUGH MONDAY/...
As of 351 AM EDT Saturday...An amplified ridge will remain overhead
across Vermont and northern New York Sunday night into Tuesday. A
surface trough will shift south Sunday night, and dry north flow
should scatter out precipitation. However, cannot entirely say we`ll
be precipitation- free due to remnant convection from storms out west
arc over the ridge axis and possibly into our area. With clouds and
little cold air flowing south, Sunday night will remain in the 40s.
Monday itself looks fairly nice. Dry air will hold until late in the
evening, when another surge of moisture will lift northeast late in
the day.

&&

.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
As of 351 AM EDT Saturday...Monday night into Tuesday, the strong
upper ridge will finally start to give way. A plume of moisture
connected to the Gulf of Mexico will slide east. There are some
differences on where a weak surface low tracks. If it tracks
overhead, then we`ll see soaking rain much of the Tuesday, but if
remains south, we could see precipitation arrive mid-morning and
afternoon and with a south to north gradient of QPF. Our pattern
does a bit of rinse and repeat as another strong ridge will develop
on Wednesday that will only gradually slide east such that we will
likely see drier conditions Wednesday followed by increasing rain
chances into the latter half of the week. Temperatures throughout
the extended will be about 5 to 10 degrees above seasonal norms.

&&

.AVIATION /12Z SATURDAY THROUGH WEDNESDAY/...
Through 12Z Sunday...VFR conditions will persist through 00z
Sunday at all terminals. Ceilings lower to MVFR after 02z
Sunday from west to east along with increasing chance for light
rain showers. Generally, no visibility reductions below 6 SM are
expected through 06z Sunday. Winds will remain relatively light
tonight before increasing a bit during the day today. Stronger
terrain- driven winds gusting 15-20 kts are possible at KMSS and
KRUT. Winds also shift to the south and southwest at 5-10 kt
after 12z Sunday with localized 15-20 kt gusts possible. LLWS
becomes an issue for KMSS and KSLK with southwest winds of 40 to
45 kt at 2000 ft elevation after 06z Sunday.

Outlook...

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

&&

.CLIMATE...
Record High Minimum Temperatures:

April 29:
KBTV: 55/2013
KPBG: 57/1974

April 30:
KPBG: 54/2004

&&

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

&&

$$
SYNOPSIS...Chai
NEAR TERM...Chai
SHORT TERM...Haynes
LONG TERM...Haynes
AVIATION...Chai
CLIMATE...WFO BTV