Nassau, New York Weather Forecast Discussion

054
FXUS61 KALY 090545
AFDALY
AREA FORECAST DISCUSSION
National Weather Service Albany NY
145 AM EDT Tue Sep 9 2025
.SYNOPSIS...
Pleasant, early September conditions persist through the
remainder of the work week, though some sneaky showers could
interrupt wholly dry conditions tonight into Wednesday for
southern areas. The only other chance for some precipitation
over the next seven days can be attributed to an upper-level
disturbance approaching for the end of the upcoming weekend, but
rain chances remain low.
&&
.DISCUSSION...
The surface cyclone that was introduced to the Northeast
yesterday, now centered across the region, will remain dominant
through Wednesday as geopotential heights increase into a meager
ridge aloft. Eastern New York and western New England will
therefore remain primarily dry through this time. However,
confidence has increased slightly in the possible occurrence of
light showers in the Southeast Catskills, lower Mid-Hudson
Valley, and southwest New England tonight into Wednesday.
As the surface high begins to shift off to our north and east
tonight, a wave of low pressure off the Southeast Coast will
glide northward, extending an inverted trough towards the Long
Island and New England Coastlines. Weak, east-southeast flow
about the northern periphery of the wave will advect Atlantic
moisture into the region while upper-level support for ascent is
enhanced through the intersection of the low into the right
entrance region of a weak, northwest to southeast-oriented,
upper- level jet displaced just inside the coast of the
Carolinas. If the track of the low maintains a more northerly
trajectory, then light showers could spread into the region,
south of Albany, late tonight and linger into Wednesday
afternoon. If the track is more northeasterly, then showers will
miss us to the south and east. However, even if some light rain
enters our CWA aloft, there is no guarantee that it would make
it to the ground. Very dry antecedent conditions paired with
lingering subsidence from the nearby high and weak ridging aloft
could mitigate any rain reaching the surface. What could help
to overcome some of the counteracting sinking air would be
upslope flow in the Litchfield Hills and Catskills. But, as
confidence remains low in even the occurrence of showers, given
the uncertainties of the progression of the synoptic
environment, the mesoscale enhancement of vertical ascent and
moistening of the column retain that much more uncertainty. That
said, since latest models are hinting more at the potential for
light showers tonight into Wednesday afternoon and
probabilities for measurable rain increased from less than 10%
to 20-25% in the aforementioned areas based on the latest HREF,
we collaborated the slight chance to chance increase in PoPs
from the null output of the NBM.
As one surface anticyclone departs, another begins to slide
south into the region from southeast Canada, reinforcing dry
conditions regionwide late Wednesday afternoon behind the
departing coastal wave. Aloft, a weak, moisture-starved
shortwave will also begin sinking south and east in association
with a low pressure system drifting eastward across Quebec. A
cold front attending this system will pass through on Thursday,
but given the lack of moisture, its passage will merely bring
back slightly below normal temperatures for Friday. High
pressure and upper-level ridging will take hold of the region
once again for Friday and Saturday before an upper-level system
threatens to bring an end to our dry stretch Saturday night into
Sunday. However, probabilities of measurable precipitation
associated with this disturbance are also low to medium (25-45%) given
the evolutionary and temporal differences in the guidance.
Therefore the NBM was not deviated from and slight chance to
chance PoPs prevail across the region. Depending on the outcome
of this system, Monday could see some lingering showers but the
scenario is too uncertain for details at this time.
Temperatures throughout the next 7 days will bounce back and
forth between normal and just below. Highs today will be in the
mid 60s to upper 70s with lows tonight spanning the upper 30s to
upper 40s due to increasing cloud cover. Lingering clouds will
keep Wednesday`s highs in the mid 60s to mid 70s with more mild
lows in the mid 40s to low 50s. Thursday will be the warmest of
the week with upper 60s to near 80 and lows similar to Wednesday
night. Behind the cold front, lows Friday will be in the mid 60s
to mid 70s with lows in the 40s and 50s. Saturday`s highs will
be just a few degrees less than Thursday with lows again in
the mid 40s to low 50s. Finally, Sunday and Monday will feature
lows in the low 60s to low/mid 70s with lows similar to those of
Saturday night.
&&
.AVIATION /06Z TUESDAY THROUGH SATURDAY/...
Through 06z Wednesday...High pressure will continue to result
in dry weather, although due to clear skies and light winds, fog
development will occur again at KGFL through around 12z with
occasional IFR/LIFR conditions. Fog is also favored at KPSF, but
will likely develop slightly later around 08z with occasional
IFR/LIFR. With northerly flow above the surface, there is a low
probability of fog at KALB drifting south from the Mohawk River
towards sunrise. However, with a dry air mass in place
confidence is low and will continue to mention prevailing VFR
conditions with BCFG. Other than some occasional MVFR vsby due
to mist, fog is not anticipated at KPOU. Any fog will dissipate
by 12z, with VFR then expected through the rest of the TAF
period. Winds will initially be near calm, becoming east-
southeast around 3-7 kt by this afternoon.
Outlook...
Wednesday Night: No Operational Impact. NO SIG WX.
Thursday: No Operational Impact. NO SIG WX.
Thursday Night: No Operational Impact. NO SIG WX.
Friday: No Operational Impact. NO SIG WX.
Friday Night: No Operational Impact. NO SIG WX.
Saturday: No Operational Impact. NO SIG WX.
Saturday Night: No Operational Impact. NO SIG WX.
Sunday: Low Operational Impact. NO SIG WX.
&&
.ALY WATCHES/WARNINGS/ADVISORIES...
CT...None.
NY...Frost Advisory until 8 AM EDT this morning for NYZ032-033-047-
     051-058-063.
MA...None.
VT...None.
&&
$$
SYNOPSIS...Gant
DISCUSSION...Gant
AVIATION...JPV

NWS ALY Office Area Forecast Discussion