Albany Office Forecast Discussion

768
FXUS61 KALY 170520
AFDALY

AREA FORECAST DISCUSSION
National Weather Service Albany NY
120 AM EDT Thu Jun 17 2021

.SYNOPSIS...
An area of high pressure will bring dry, seasonable weather
through Friday afternoon. Showers and thunderstorms will return
Friday night through Saturday along with warmer and more humid
conditions. Warm weather continues on Sunday but it should be
mostly dry.

&&

.NEAR TERM /THROUGH TODAY/...
.UPDATE...
As of 120 AM EDT...It remains a mostly clear, dry and cool night
across the region. Temperatures at this hour vary across the
region with upper 30s across some higher terrain areas to the
low to mid-50s along the Hudson Valley. Still expect most areas
to fall into the 40s with some 30s in the higher terrain. Patchy
fog will be possible in some areas (and perhaps some localized
areas of frost in the Adirondacks or eastern Catskills).

Previous discussion:
High pressure at the surface centered over the Ohio Valley will
advance into the local area overnight, while aloft we remain
under cyclonic flow a bit longer. Have some mid and high level
clouds streaming across the region and winds are diminishing.
With mostly clear skies and light winds have good radiational
cooling conditions and temperatures are falling. Still expecting
lows mainly in the 40s with some mid to upper 30s across the
western Adirondacks and the high terrain of the eastern
Catskills and southern Greens (where some patches of frost are
possible). Any patchy fog is expected to be limited to favored
areas north of I-90. Forecast lows are around 10F below climo.

Thursday, the upper trough shifts eastward somewhat, which
should result in highs a couple degrees warmer than Wednesday
under mainly clear skies and good mixing. Highs in the upper 60s
to upper 70s expected, near to slightly below climo.

&&

.SHORT TERM /TONIGHT THROUGH SATURDAY/...
Starting Thursday night, the upper trough shifts eastward, briefly
replaced by ridging before transitioning to more zonal flow. This
will result in an increase in temperatures and eventually deep layer
moisture. Thursday night is expected to be rather tranquil and
somewhat cool again, as current model solutions hold off return flow
until Friday morning. Temperatures are expected to get a boost
Friday relative to midweek as low level southwesterly flow increases
ahead of an approaching shortwave trough. clouds will increase late
in the day, but highs back in the low 80s for lower elevations are
expected.

Stronger warm advection looks to arrive late Friday into Friday
night with PWATs rising near 1.50 inches. Isentropic lift and DCVA
will likely result in scattered showers, with isolated thunderstorms
also possible as Showalter values fall below zero. A somewhat mild
night is expected with lows in the mid-50s to mid-60s.

Saturday, synoptic scale lifting looks to increase with stronger
height falls and the poleward exit region of a seasonably strong
upper jet becoming favorably positioned over the region. Models are
quite variable with the timing and strength of a possible dominant
shortwave moving from the western Great Lakes into the Northeast.
With the strong midlevel flow, there exists a chance for
organized/strong convection, but little can be said about the
details at this point. Other complicating factors are potential for
a muddled convective environment due to lingering morning
clouds/showers and unimpressive midlevel lapse rates. Still pockets
of heating could yield at least modest instability with highs
forecast to range from the mid-70s to upper 80s and dewpoints
climbing into the low to mid-60s. Enough confidence at this point
for high chance to low likely PoPs with chance of thunderstorms.

&&

.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
The long term period will feature pleasant weather for the second
half of Father`s Day weekend, but chances for precipitation increase
again for the first half of the work week, although conditions look
to improve by the middle of the week. See below for the details...

We begin the period Saturday night with the upper trough responsible
for Saturday`s showers and thunderstorms departing to the northeast.
A cold front will pass through the region, and the associated
surface cyclone which will be located in southern Canada will move
away from the region. Therefore, there could be some lingering
showers and possibly a rumble of thunder early Saturday night,
especially for northern and eastern areas. Behind the cold, however,
lingering showers are expected to diminish as cold air advection
(CAA) and subsidence take over. Skies should become partly to mostly
clear overnight, with low temperatures dropping into the low to mid
50s.

Sunday looks to be a beautiful spring-like day. Weak high pressure
builds into the region with upper-level shortwave ridging moving in
from the west. The result will be large-scale subsidence that will
lead to mostly clear skies and high temperatures in the low-mid 80s
in the Hudson Valley and upper 70s to low 80s elsewhere. It will
also be breezy with wind gusts of 10-15 mph during the afternoon.

Unfortunately, the nice weather comes to an end for the beginning of
the work week. Sunday night, a warm front will move northward across
the region, leading to advection of warmer and more humid air into
the region. Meanwhile, a large-scale upper-level trough will dig
southward from Canada into the central U.S. There multiple shortwave
disturbances will propagate through this longwave trough, which
could lead to periods of active weather for our region next Monday
and Tuesday.

During the day Monday, the best upper-level forcing
looks to remain to our west, although the surface cold front will
slowly approach the region during the day Monday which could lead to
scattered showers and a few isolated rumbles of thunder. It will
also be warmer and more humid, with high temperatures in the mid to
upper 80s with dew points in the mid to upper 60s for much of the
region. We will also have to watch the remnants of the potential
tropical system currently located in the Gulf of Mexico. There is
still some uncertainty as to how quickly this feature will move
northward. However, if it is picked up by the upper-level trough,
then the associated moisture could be advected into our region late
Monday. At this time, guidance suggests that most of this moisture
remains to our south and east, but we will continue to monitor over
the next several days.

Tuesday, the potent upper trough moves closer to our region as the
surface sharp cold front moves into our area. There looks to be
plenty of forcing for ascent. In addition to the sharp upper trough,
we will be in the right entrance region of a 110+ kt 300 mb jet
streak. GEFS plumes suggest PWAT values reaching 1.7-1.9", which is
2-3 standard deviations above normal for this time of year, so with
the overlap of deep moisture and synoptic forcing, Tuesday looks to
have a decent shot at appreciable rainfall for most of the region.
Given that this event is almost a week away, there is still
uncertainty in the forecast, namely the timing of the frontal
passage and intensity of the synoptic forcing for ascent. Yet, with
surprisingly good model agreement on the big-picture set up, have
decided to include likely PoPs for much of the region on Tuesday.

The strong cold front looks to pass through the region sometime
Tuesday afternoon or Tuesday night. This will usher much cooler and
drier air into the region, with at least partial clearing expected
as well. Assuming the front does indeed clear our region by
Wednesday morning as guidance suggests, Wednesday should be another
nice day with cooler temperatures, lower humidity, and mostly clear
conditions.

&&

.AVIATION /05Z THURSDAY THROUGH MONDAY/...
High pressure will control our weather through this evening. Just
few to scattered clouds above 3000 feet through this evening.
Visibilities remaining VFR, too.

Light and variable winds through mid morning become south to
southwest initially develop with the flow shifting to the west-
northwest. Some gusts into the teens are expected at KALB and KPSF
during the afternoon. Winds diminish toward evening.

Outlook...

Thursday Night: No Operational Impact. NO SIG WX.
Friday: Low Operational Impact. Slight Chance of SHRA.
Friday Night: High Operational Impact. Likely SHRA...TSRA.
Saturday: High Operational Impact. Likely SHRA...TSRA.
Saturday Night: Low Operational Impact. Slight Chance of SHRA.
Sunday: No Operational Impact. NO SIG WX.
Sunday Night: Low Operational Impact. NO SIG WX.
Monday: Moderate Operational Impact. Chance of SHRA...TSRA.

&&

.FIRE WEATHER...
Another seasonably dry day is expected Thursday with minimum RH
values falling into the 30 to 40 percent range. Moderate
westerly winds are expected. RH values recover to 70-90 percent
Thursday night. Minimum RH values Friday fall to 35-45 percent
with moderate southwesterly winds, with showers and
thunderstorms becoming increasingly likely Friday night into
Saturday.

&&

.HYDROLOGY...
Dry weather is expected to continue Thursday into most of
Friday. Deep moisture increasing in conjunction with several
disturbances will produce unsettled weather Friday night into
Saturday. Widespread hydro issues are not expected, but locally
heavy downpours are possible. After a dry day Sunday, additional
periods of precipitation are expected early next week.

For details on specific area rivers and lakes, including
observed and forecast river stages and lake elevations, please
visit the Advanced Hydrologic Prediction Service /AHPS/ graphs
on our website.

&&

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

&&

$$
SYNOPSIS...Rathbun
NEAR TERM...IAA/Thompson/Rathbun
SHORT TERM...Thompson
LONG TERM...Main
AVIATION...NAS
FIRE WEATHER...Thompson
HYDROLOGY...Thompson

NWS ALY Office Area Forecast Discussion