Albany, NY WFO Forecast Discussion

372
FXUS61 KALY 090756
AFDALY

AREA FORECAST DISCUSSION
National Weather Service Albany NY
356 AM EDT Fri May 9 2025

.SYNOPSIS...
A coastal low pressure system will bring periods of rain
today into tonight with the rain becoming heavy at times in the late
morning through the afternoon. This rainfall may result in some
flooding of small streams, urban and low lying areas and minor river
flooding before tapering off on Saturday.  High pressure builds in
with drier and more seasonable temperatures for Mothers Day, as the
fair weather with moderating temperatures may last until Tuesday.


&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
Key Messages:

-  High confidence for a widespread heavy rain event today into
   Saturday morning. The wet antecedent conditions in place will
   increase the potential for minor flooding of rivers and
   creeks, as well as flooding of urban,low-lying and poor
   drainage areas.

-  Flood Watch in effect for the entire forecast area except
   Herkimer and Hamilton Counties until 8 am EDT Saturday.

As of 356 AM EDT...The 500 hPa height field overlaid on the
water vapor imagery this morning shows a stretched and elongated
positively tilted closed low over southeast Canada, the eastern
Great Lakes Region extending south/southwest into the Ohio
Valley and western PA. An inverted sfc trough extended northeast
of a developing cyclone near the Mid Atlantic Coast which is
focusing the surge of moisture this morning. A band of rain
continues to form, as the showers will consolidate into a rain
shield. A sfc anticyclone over s-central Quebec continues to
funnel southward chilly air over upstate NY and New England.

In the deformation axis of the developing wave, low to mid
level FGEN will enhance with support from the left exit region
of a mid and upper level jet streak in the late morning through
the afternoon across the forecast area. PWATs rise above normal
with moisture advection increasing from the Gulf and Atlantic.
The mid and upper level dynamics with the enhanced FGEN will
allow for a synoptic rain band to potentially form with the
hourly rainfall rates potentially increasing to 0.25-0.50"/hr
based on the latest HREFs this afternoon. The CAMs are tricky
with the placement of the enhanced rainfall. The QG lift is
strong ahead of the warm front and north/northeast of the wave
approaching. The 3-km NAMnest would have the heavy rain axis
slightly further westward over the forecast area with the Lake
George Region/Capital Region/northeast Catskills getting hit by
the rainband. The 3-km HRRR is slightly further east with
western New England and perhaps the Taconics getting the heavier
rain. The conceptual model for closed lows based on CSTAR
research done with UAlbany shows that positively tilted to
neutral tilted closed/cutoff lows produced heavy rain and
possible flooding. We are fairly confident a widespread soaker
is going to happen and with the wet antecedent conditions from
last weekend/earlier in the week...we will be monitoring for
stream, creek and minor river flooding and perhaps isolated
moderate flooding. Urban and poor drainage flooding will also
likely occur.

Also, some elevated instability will be in place ahead of the
wave and warm front. There are some signals of moist/conditional
symmetric instability in the guidance too due to the strong
theta-e advection. We did keep a slight chance of thunderstorms
in the late afternoon into the early evening for heavy rainfall
for the locations along and east of the Hudson River Valley into
western New England. We also added the phrasing the rain may be
heavy at times for the possible synoptic rain band. It will be
dank and chilly today with the rain cooled air. We leaned closer
to the cooler MET guidance which was a few degrees below the
starting point NBM we begin forecasts with. Highs will be in the
mid 40s to around 50F over the higher terrain and mainly lower
to mid 50s in the valleys and across NW CT.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH SUNDAY NIGHT/...
Key Messages:

-  Total rainfall amounts exceeding 1.5" are possible in the
   30-60% chance range for most of eastern NY (except the
   western Adirondacks and western Mohawk Valley) and western
   New England for the 24-hr time frame ending 8 am Saturday.

Discussion:

By early this evening the closed/cut-off 500 hPa low will be
situated over w-central PA. The coastal low will be near or
over NYC or southern New England. Periods of light to moderate
rainfall will continue with some heavier bursts over the eastern
Catskills, Capital Region, Berkshires north and east. A few
rumbles of thunder could be possible north and east of Albany. A
dry slot may start to impact the mid Hudson Valley and NW CT
shortly before or just after midnight. The axis of deep moisture
off the Atlantic begins to shift east of the region over
central and eastern New England with the coastal cyclone. Total
rainfall tallies will be in the 1-2.5" range for most of the
region by daybreak Saturday. Some amounts up to 3" may occur in
the eastern Catskills, and possibly the Berkshires and
east/southeast VT. Lows will be cool in the 40s with some upper
30s over the southern Dacks.

The rainfall will become more showery in nature towards
daybreak due to the cyclonic vorticity advection of the closed
low. Some mid and upper level deformation zone showers may
persist the longest north and east of Albany over the Lake
George Region and southern VT. Most of the region has a good
chance for 1.5" or greater of rainfall based on the 24-hr NBM
probs ending 8 am Sat. The probs are 30-60% outside the western
Mohawk Valley and western Dacks. The Flood Watch goes until 8 am
and there is a 6-12 hr delay in river response sometimes. We did
add northern Washington and northern Warren Counties to the
Watch since the Schroon and Mettawee are forecast to rise 2-3
tenths close to the minor flood stage. See the hydro discussion
for further details.

The stacked or occluded cyclone pulls away into the Gulf of
Maine by Saturday afternoon with the scattered showers ending
from west to east especially north of the Capital Region. It
will become breezy and remain cool with below normal temps. Max
temps will run about 5-10 degrees below normal with 50s over the
higher terrain (some upper 40s over the mtn tops) and lower to
mid 60s in the valleys. The skies continue to clear with breezy
conditions Sat night with high pressure building in from the
Great Lakes Region and south of James Bay. Lows will be in the
mid 30s to around 40F over the mtns and lower to mid 40s in the
valleys.

The close of the weekend and Mothers Day is shaping up to be a
nice day with high pressure ridging eastward from the Great
Lakes Region over NY and New England. Expect mostly sunny skies
and breezy conditions with temps trending closer to early May
seasonable readings with mid 50s to mid/upper 60s over the
forecast area. The sfc anticyclone builds in over the region Sun
night with mostly clear and calm conditions for radiational
cooling with lows in the 30s to lower 40s with some patchy frost
especially over the higher terrain.

&&

.LONG TERM /MONDAY THROUGH THURSDAY/...
Key Messages:

- Dry weather with moderating temperatures early next week

- Precipitation chances increase again beginning Wednesday

Discussion:

High pressure will be centered just off the Mid-Atlantic to start
the long term period, with mid-level ridging not too far away to the
west. As these continue to march east, it will allow for south to
southwesterly flow to set up across the region with moderating
temperatures (925-850 hPa temps moderating to around +10C to +15C).
As a result, highs Monday and Tuesday should have no trouble
climbing into the 70s and even 80s (especially in valley locations).

Our next chance of rain arrives Wednesday as an upper level low
across the lower Mississippi River Valley translates northeast into
the Ohio River Valley. This system looks to slowly progress
northeast before phasing with an approaching trough late in the
period. As a result, precipitation chances will linger late into
next week. Given uncertainties on exact precip placement, continue
to run with NBM which favor widespread slight to chance (30-50%)
POPs. Thunderstorms are also possible given the increasing moisture
and warm temperatures, though confidence of severe weather remains
low at this time.

&&

.AVIATION /07Z FRIDAY THROUGH TUESDAY/...
Through 06z/Sat...Mixed VFR/MVFR conditions initially will
continue over the next few hours with a few passing light rain
showers. Precipitation increases in coverage through early
morning and becomes a widespread light to occasionally moderate
rain by mid morning, which will persist for the remainder of
the TAF period. Conditions will deteriorate further to IFR, with
low potential for LIFR conditions in heavier rain showers.
Winds will remain steady out of the north to northeast around
5-10 kts for the period.

Outlook...

Saturday Night to Sunday: Low Operational Impact. Breezy. NO
SIG WX.
Sunday Night to Tuesday: No Operational Impact. NO SIG WX.

&&

.HYDROLOGY...
The Flood Watch was expanded to include northern Warren and
northern Washington Counties. The Flood Watch covers all of
eastern NY and western New England from 5 am today to 7 am
Saturday except for Herkimer and Hamilton Counties.

A low pressure system will bring a prolonged period of rainfall
for possible flooding this morning into Saturday morning. The
ground is soaked and rather saturated after the heavy rainfall
that occurred earlier this week. 1 to 3 inches of rainfall is
anticipated this morning into Saturday morning. WPC has placed
most of our region into a marginal risk for excessive rainfall
during this period. While an isolated flash flooding would be
possible with any training and heavier rainfall rates, the
greater threat appears to be the potential for additional river
and poor drainage flooding due to a prolonged period of steady
moderate rainfall, with brief periods of heavier bursts. The
latest NERFC forecasts shows potential minor flooding along the
Hoosic River, Housatonic River and Esopus Creek. Also some
flooding is possible along the Still River near Brookfield. In
addition, ponding of water is expected in poor drainage, urban
and low lying areas.

Keep updated with the latest river observations and forecasts
from our National Water Prediction Service (NWPS) webpage at
water.noaa.gov/wfo/aly.

&&

.ALY WATCHES/WARNINGS/ADVISORIES...
CT...Flood Watch through Saturday morning for CTZ001-013.
NY...Flood Watch through Saturday morning for NYZ039>043-047>054-
     058>061-063>066-082>084.
MA...Flood Watch through Saturday morning for MAZ001-025.
VT...Flood Watch through Saturday morning for VTZ013>015.

&&

$$

SYNOPSIS...Wasula
NEAR TERM...Wasula
SHORT TERM...Wasula
LONG TERM...Speck
AVIATION...Speck
HYDROLOGY...Frugis/Wasula

NWS ALY Office Area Forecast Discussion