411
FXUS61 KALY 121747
AFDALY

AREA FORECAST DISCUSSION
National Weather Service Albany NY
147 PM EDT Sun May 12 2024

.SYNOPSIS...
An upper level low will depart the region tonight with rain
showers ending along with partial clearing. Warmer weather
returns early this week with continued chances at some showers
and possible thunderstorms each day through midweek. Drier and
seasonable weather may return for late week.

&&

.NEAR TERM /THROUGH TONIGHT/...
.UPDATE...As of 120 PM EDT, latest water vapor imagery shows an
upper-level low now positioned across eastern New England as
the surface low over central Pennsylvania dissipates. While
forcing is beginning to depart, continued upper-level troughing
overhead will result in some isolated to scattered showers
through the afternoon. The most persistent rainfall today and
still currently has been across portions of the Lake
George/Washington County region into southern Vermont.
Temperatures will generally top out in the 50s with some pockets
of lower 60s possible in the valley areas.

Rising upper-level heights and surface high pressure centered to
our east will bring an end to showers this evening with some
partial clearing overnight, which may provide some viewing
conditions for tonight`s aurora. Visit the Space Weather
Prediction Center website for more. Some patchy fog may also
develop along some of the river valleys where the more
persistent clearing occurs. Lows will fall back into the upper
30s to mid-40s.

&&

.SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
Flattened upper ridging builds in from the west through Monday,
yielding a drier day amidst the recently wet pattern. The break
from rain showers is brief, however, as another upper-level low
slides eastward across Ontario and Quebec while a warm front
lifts across the region Monday afternoon into Monday night. The
best chance for showers will be in the southern Adirondacks and
adjacent areas north and west of Albany through the afternoon,
and generally north of I-90 through Monday night. Temperatures
trend upward toward seasonal norms, reaching afternoon highs in
the upper 50s to low 60s in high terrain and mid to upper 60s
at lower elevations, and falling to mild overnight lows in the
upper 40s to mid 50s across the region.

Warm frontal rain showers will exit to the north and east by
late Monday night, while a trailing cold front arrives from the
west by Tuesday afternoon to evening. Ahead of the cold front,
gusty south winds will aid in advecting ample moisture into the
region, setting the stage for a soaking rain with the potential
for sufficient instability for a few rumbles of thunder as the
boundary slowly progresses to the southeast Tuesday evening
into Tuesday night. Persistent ridging over the North Atlantic
will see the front slow or even stall overnight. Within the
warm sector on Tuesday afternoon, temperatures look to rise
above normal, reaching highs in the 60s in high terrain and low
to mid 70s at lower elevations, while continued rain showers
will yield very mild overnight lows in the 50s across the
region.

&&

.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
A slow moving front from the Great Lakes will approach eastern NY on
Wednesday. Its parent low will be displaced well to our north near
the Hudson Bay and weakens as it pushes through Quebec. This plus
the fact that the moisture and thermal gradient along the boundary
is rather weak suggests the boundary will likely wash out as it
pushes east during the day on Wednesday. While guidance does suggest
the majority of the rain remains mainly west of the Capital
District, we also will be monitoring an upper level trough tracking
eastward from the Ohio Valley. The shortwave trough looks to be
positioned in the favorable left exit region of a jet streak
oriented over the Southeast U.S which will help steer the trough
towards the East Coast. Some guidance still indicates that the
trough may close off which would slow down its eastward progression
and delay the onset of POPs for the Capital District and areas south
of I-90 until later in the day Wednesday or even Wednesday night.
Given ongoing uncertainties, we show likely POPs for areas mainly
south of I-90 where rain showers from the incoming trough should
reach while areas north/west of the Capital District max out at
chance POPs due to the weakening/washed out boundary. PWATs ahead of
the boundary exceed 1 inch so some weak instability may be generated
resulting in steadier periods of rain, especially where any
thunderstorms can develop. Otherwise, highs on Wednesday should only
reach into the mid to upper 60s with some near 70 degree readings in
the valley. Increased PWATs streaming ahead of the boundary will
help make it feel muggier/warmer.

Between the weakening boundary and slow moving upper level trough,
we maintain chance and slight chance POPs through the first half of
Wednesday night before trending POPs lower. POPs may trend lower in
future updates if confidence increases that the better forcing from
the upper level low remains to our south and the boundary indeed
washes out before reaching the Hudson River. Otherwise, expecting a
cloudy, slightly muggy, and mild night with lows only in the 50s.

Some showers may linger into Thursday, mainly in far southern zones,
as the upper level trough continues to slowly push off shore. If the
best forcing remains south, Thursday should trend drier. Otherwise,
temperatures should end up warmer than Wednesday given less
precipitation and the warmer air mass that spread ahead of the
boundary still in place. Expecting highs to reach into the low to
mid 70s.

Friday continues to look dry and seasonably warm as upper level
ridging and sfc high pressure from northern New England build
overhead. However, the dry weather appears short-lived as unsettled
weather returns for the weekend.

&&

.AVIATION /18Z SUNDAY THROUGH FRIDAY/...
Through 18z Monday...Mainly MVFR conditions in place this
afternoon as an upper level low tracks east across the region.
Borderline IFR cigs may occur at KGFL through around 19z.
Scattered showers will be around, with the best chances for a
few rounds of -SHRA at KGFL/KPSF where TEMPO has been included.
Will mention VCSH at KALB. Any -SHRA should stay north of KPOU.

As the upper low moves into New England this evening, conditions
are expected to improve to VFR. BKN-OVC cigs will also likely
to scour out to FEW-SCT coverage through the evening hours. With
not much drying overnight and fairly moist ground conditions,
there is a threat of fog with MVFR/IFR possible. Will include
mention of IFR at most favored sites KGFL/KPSF with MVFR for now
at KALB/KPOU. Will continue to monitor trends.

Winds will be variable around 6 kt or less through the rest of
the day, becoming near calm tonight.

Outlook...

Monday Night: Low Operational Impact. Slight Chance of SHRA.
Tuesday: High Operational Impact. Likely SHRA...TSRA.
Tuesday Night: High Operational Impact. Definite SHRA...TSRA.
Wednesday: High Operational Impact. Likely SHRA...TSRA.
Wednesday Night: Moderate Operational Impact. Chance of SHRA...TSRA.
Thursday: Low Operational Impact. Slight Chance of SHRA.
Thursday Night: No Operational Impact. NO SIG WX.

&&

.ALY WATCHES/WARNINGS/ADVISORIES...
CT...None.
NY...None.
MA...None.
VT...None.

&&

$$

SYNOPSIS...Rathbun
NEAR TERM...Rathbun
SHORT TERM...Picard
LONG TERM...Speciale
AVIATION...JPV