896
FXUS61 KALY 121105
AFDALY

AREA FORECAST DISCUSSION
National Weather Service Albany NY
705 AM EDT Sun May 12 2024

.SYNOPSIS...
An upper-level low will bring continued cool and cloudy weather
for Mother`s Day. Rain showers will continue this morning
before tapering through the afternoon and evening. Warmer
temperatures near seasonal norms are expected beginning Monday,
while an unsettled pattern will bring additional chances for
rain showers through midweek.

&&

.NEAR TERM /THROUGH TONIGHT/...
.UPDATE...As of 0645 AM EDT, upper low is currently centered
along the New York-Pennsylvania border and will continue to
slide eastward through this afternoon. Rain shower coverage has
increased and organized into bands, one extending from the
western Mohawk Valley, across the Schoharie Valley and eastern
Catskills into the Mid-Hudson, and another from roughly the
Southern Tier of NYS to northern New Jersey. Showers will
continue to pivot over the region as the upper low passes nearly
overhead, before diminishing this afternoon and evening as
forcing exits eastward. With minor adjustments to precipitation
chances through the morning, the forecast remains on track; see
previous discussion below...

.PREV DISCUSSION [0430 AM EDT]...A large upper-level low
apparent on moisture channel imagery continues to track from the
Great Lakes into the Northeast early this morning. The
shortwave responsible for the digging trough will round its base
through this morning, contributing to a new area of deepening
over the Gulf of Maine while the upper low overhead weakens.
Resultant scattered rain showers will continue across the region
through the morning before diminishing locally through the
afternoon and evening as the forcing exits eastward. Largely
overcast skies similarly persist into the afternoon, with some
clearing to partly cloudy skies expected through the evening and
overnight.

Dry conditions return by this evening as upper heights rise
rapidly behind the departing trough as brief upper ridging
builds in. Seasonably cool temperatures some 5 to 10 degrees
below normal nonetheless continue through tonight, with
afternoon highs reaching the upper 40s to mid 50s in high
terrain and upper 50s to low 60s at lower elevations, and
overnight lows falling to the upper 30s to mid 40s across the
region.

&&

.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 /12Z SUNDAY THROUGH THURSDAY/...
Scattered light rain showers will continue through this morning
and where rain showers occur, MVFR ceilings are likely.
Visibility should mainly stay VFR but brief steadier periods of
rain (especially POU) can support brief periods of MVFR vis and
we highlighted this with TEMPO groups. MVFR ceilings should
improve after 18 UTC (except PSF where MVFR cigs likely linger)
but with our upper level disturbance and associated upper level
cold pool moving overhead, additional showers will likely
redevelop. Again, coverage should be scattered but where showers
redevelop, MVFR ceilings will likely return given moisture in
the low- levels.

By 00 UTC/13, showers should diminish as the upper level
disturbance exits to our east and ridging returns. VFR
conditions likely return by 00 - 03 UTC at all sites as skies
clear. Given wet weather and clearing skies, fog is possible at
POU, GFL, and PSF resulting in MVFR visibility and IFR
ceilings. Not enough confidence to include IFR ceilings but we
will monitor trends closely and adjusted TAFs as needed.

Light south to southeasterly winds tonight sustained around
5kts will remain near or even under 5kts through 00 UTC before
winds turn light and variable through the end of the TAF
period.

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...Picard
NEAR TERM...Picard
SHORT TERM...Picard
LONG TERM...Speciale
AVIATION...Speciale