040
FXUS61 KALY 181801
AFDALY

Area Forecast Discussion
National Weather Service Albany NY
201 PM EDT Fri Sep 18 2026

.WHAT HAS CHANGED...
Current models are now hinting that Sunday`s precipitation coverage
will extend slightly northward, otherwise the previous forecast
remains largely on track.  While we are still expecting widespread
rain Sunday, flash flooding does not appear to be a concern for our
forecast area.

&&

.KEY MESSAGES...
1) Dry and cool weather is expected through tomorrow.

2) A low pressure system to our south will bring widespread
beneficial rain to the region Sunday, followed by drier and cool
weather for the first half of the week.

&&

.DISCUSSION...
KEY MESSAGE 1...

Current surface analysis shows the second and stronger cold front
moving through the region with a high pressure system building ahead
to our north. This will allow for a very pleasant
afternoon/evening with highs in the 60s (terrain) to mid 70s
(valleys)along with a light northerly breeze. Drier air will
begin to filter in lowering dewpoints into the 50s through this
evening, however some patchy fog will still be possible in the
typical river valleys and near wetlands. With the ADKs being
closest to the center of the surface high, favorable radiational
cooling conditions will lower tonight`s low temperatures for
higher terrain areas into the mid 30s which may allow for some
patchy frost to develop in the sheltered areas, but coverage is
not expected to be widespread enough to warrant frost advisory
issuance. With the surface high still sliding by to our north
tomorrow, it is expected to be a very nice early-fall day with
highs generally in the 60s topping out near 70 in the Mid-Hudson
Valley. Dewpoints in the 30s and 40s will make for very
comfortable conditions throughout the region.


KEY MESSAGE 2...

Moisture begins to return late Saturday night into Sunday, as
an upper level shortwave develops over the Great Lakes and
track through the region timed with a low pressure system and
associated frontal boundary stalling to our south along the
coast. These will be the primary drivers for synoptic-scale
forcing and isentropic lift, however a strengthening jet streak
to our north, putting most of the region in the right rear
entrance region, will additionally aid with divergence aloft.
The frontal boundary`s warm sector will remain to our south
however strong mid and low level warm air advection will
transport suffienct moisture northwards into our region. The
latest model guidance/CAMs have PWATs Sunday afternoon ranging
from 1.5 to 2.0" with the NAEFS ensemble showing PWAT anomalies
increasing to +1 to + 1.5" STDEV by Sunday afternoon, which is
just slightly above the daily climatological mean value for our
region. Widespread rain and showers are expected to begin
Saturday night and become steady through much of Sunday before
exiting Sunday night. There is still some uncertainty of where
the heaviest rainfall axis will be, but the majority of models
have the heaviest rain falling across southern areas where the
best mid-level forcing will be. Total rainfall amounts generally
look to be 0.25 to 0.75" north of I-90, with 1 to 1.5" south,
except near I-84 where some locally higher amounts up to around
2" will be possible.

Probabilistic guidance has a 60 to 70% chance for >1" and a 30 to 40%
chance for >2" areas south of I-90. There is a 20 to 30% chance for
>1" areas north of I-90. WPC has placed a Marginal ERO for mainly I-
90 south with a Slight ERO clipping the southern portions of Ulster,
Dutchess, and Litchfield counties. Given that 1-hr FFG values are
generally >2", rain will be stratiform in nature, and little to no
instability, there is a very low chance for hydro threats. However
some nuisance ponding of water in the typical low-lying and poor
drainage areas is possible. Due to widespread rain/wetbulbing, highs
Sunday may not make it out of the 50s for many areas.

From previous discussion:

Showers should come to an end Sunday night as a strengthening sfc
high builds into southeastern Canada beneath confluent upper flow.
This will help push the frontal boundary back south, so Monday looks
relatively dry at this time. For Tuesday through the middle of next
week, there is some uncertainty if the sfc high will continue to
suppress this boundary to our south or if the sfc high will retreat
enough that the boundary is able to lift north and bring some
renewed shower chances to our southern areas. Given the strength of
the sfc high, we are leaning towards the drier solution. With our
area expected to be on the cool side of the frontal boundary, temps
should remain below normal with highs in the 50s (terrain) to 60s
(elsewhere) and lows in the upper 30s to 40s each day/night.

&&

.AVIATION /18Z FRIDAY THROUGH WEDNESDAY/...
Through 18z Saturday...VFR conditions are in place across all
terminals this afternoon with widespread fair weather cumulus
developed throughout eastern New York and western New England.
As we lose daytime heating later this evening, these 4-5 kft
clouds will dissipate and high clouds will stream into the
region overnight. Ceilings will eventually develop, mitigating
fog for at least the vast majority of the overnight period.
However, as ceilings break before sunrise tomorrow morning and
winds go very light to calm, some light fog cannot be ruled out
at the usual places of GFL and PSF. As confidence is lower in
this element of the forecast given sufficient cloud coverage and
light breeze through most of the night, only included a TEMPO
for MVFR visibility as a result. Should any fog develop, VFR
conditions will swiftly return once ample sunshine burns it off
tomorrow morning. Winds throughout the period will largely
prevail out of the north to northwest. Through the remainder of
the afternoon into this evening, sustained wind speeds will
range from about 8-12 kt with occasional gusts up to 20 kt.
Tonight, sustained speeds will fall below 10 kt and remain
consistent through the remainder of the 18z TAF period.

Outlook...

Saturday Night: High Operational Impact. Likely SHRA.
Sunday: High Operational Impact. Definite SHRA.
Sunday Night: Moderate Operational Impact. Chance of SHRA.
Monday: No Operational Impact. NO SIG WX.
Monday Night: No Operational Impact. NO SIG WX.
Tuesday: No Operational Impact. NO SIG WX.
Tuesday Night: No Operational Impact. NO SIG WX.
Wednesday: No Operational Impact. NO SIG WX.

&&

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

&&

$$

DISCUSSION...53/35
AVIATION...12