496
FXUS61 KALY 261852
AFDALY

AREA FORECAST DISCUSSION
National Weather Service Albany NY
252 PM EDT Thu Sep 26 2024

.SYNOPSIS...
Rain showers this afternoon diminish from northwest to southeast
this evening as a cold front moves across the region. Some
periods of moderate rain are possible south of I-90. Skies
partially clear tonight along and north of I-90 resulting in
some fog, especially in river valleys. Canadian high pressure
builds southward tomorrow into the weekend giving us drier
weather although a few rain showers may sneak back into areas
south I-90 as our front retrogrades northward.

&&

.NEAR TERM /THROUGH FRIDAY/...
Areas of rain showers continue to overspread much of eastern NY
and western New England as GOES16 water vapor imagery shows our
upper level closed parent low slowly tracking through Ontario
with its attendant cold front pressing southeastward through
western NY/the Tug Hill. A jet streak also looks to develop on
the southern periphery of the closed low. Meanwhile, the overall
synoptic pattern across the Eastern CONUS shows a closed low
spinning over the MS Valley with a strong anticyclone off the
Southeast U.S coast while Hurricane Helene tracks northward
through the Gulf towards the Florida panhandle. See
hurricanes.gov for more info on Helene.

This set-up supports strong southerly winds funneling moisture
northward from the Gulf of Mexico into the Northeast with a
plume of 1 - 1.75" PWATs nosing ahead of the boundary. As such,
latest SPC mesoscale analysis also shows enhanced 925 - 850 hPa
moisture transport vectors directed along and ahead of the
incoming cold front with dew points across of the local area in
the upper 50s to mid 60s. The 12 UTC ALY sounding also shows
impressive PWATs for late September standards at 1.64 inches.
The moisture rich environment ahead of the incoming front
combined with the slow movement of the closed low/boundary will
allow showers to continue developing and spreading across the
region well into the afternoon. It will take until 19 - 21 UTC
before showers finally start to diminish from northwest to
southeast as the front sweeps through, first ending in the
western/southern Adirondacks before showers end in the Capital
Region by the P.M rush hour.

Enhanced upper level divergence in the equatorward entrance
region of the aforementioned jet streak within the moisture
rich environment looks to support some increased rainfall rates
this afternoon into early evening in the eastern Catskills into
the mid-Hudson Valley and Berkshire/Litchfield County. Latest
CAMS support this especially the NAM/HRRR with the HREF
probabilistic guidance showing 60 - 70% chance for >0.50" in
3-hours between 18 and 21 UTC. The boundary slows down as it
presses south of I-90 and becomes oriented west-east. This will
allow showers to linger and continue past sunset into this
evening for the mid-Hudson Valley, eastern Catskill into western
New England before the wind shift boundary catches up and kicks
the showers out of the area by Midnight.

Overall, this beneficial, soaking rain will result in total QPF
amounts ranging from 0.75 to 1.50" from the Capital District
into the southern/western Adirondacks with 0.50 to 1.00" south
of I-90. High temperatures today will be limited to the low to
mid 60s thanks to widespread cloud coverage and showers but
elevated dew points will keep it feeling muggy.

&&

.SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY NIGHT/...
Expect drying conditions after Midnight tonight with clearing
mainly near and north of I-90 as sfc boundary shifts towards the
NYC area. Skies remain cloudy south where the mid-level boundary
stalls. Fog likely develops in river valleys north of I-90
given wet soils/recent rain but fog will be limited where skies
remain cloudy south of I-90. Temperatures cool into the upper
40s to low 50s north of I-90 and remain mild/muggy south of this
interstate only dropping into the upper 50s to around 60.

The sfc cold front continues pressing further into Central NJ
during the day Friday but the mid-level boundary hangs around
the mid-Hudson or Lower Hudson Valley. As Canadian high
pressure and subsidence/dry air aloft build in the wake of our
departing closed low, early fog in river valleys will give way
to mainly sunny near and north of I-90. Skies remain partly to
mostly cloudy to the south closer to our stalled boundary. With
a mild air mass still in place aloft and a light northerly flow
reducing the humidity, temperatures will warm nicely into the
low to mid 70s Friday afternoon giving us a pleasant end to the
work week.

Our stalled sfc boundary retreats back northward Friday night
into Saturday as a closed low in the MS/TN Valley absorbs the
remnants of Helene resulting in downstream ridging building in
the mid-Atlantic. There remains uncertainty on just how far
north the boundary advances as our Canadian high slowly lifts
into northern New England; however, we do expect increasing
cloud coverage from south to north during this period. We slowly
expand slight chance POPs into the eastern Catskills, mid-
Hudson Valley and into Berkshire/Litchfield County late Friday
night into Saturday but ensemble guidance suggests incoming
showers will be light and isolated to widely scattered as
moisture and the boundary enters into an area of stronger
confluence established across the Northeast.

Despite increasing clouds on Saturday, temperatures will still
warm into the low to mid 70s as the mild air mass remains in
place aloft. Humidity also gradually increases in response to
the retreating boundary.

We remain mostly cloudy Saturday night but the potential for
showers decreases through the night as our boundary shifts
southward in response to high pressure in the Midwest/Great
Lakes builds into the Northeast. Temperatures remain mild only
dropping into the mid to upper 50s thanks to cloud coverage.

Mostly cloudy skies start the day on Sunday but should give way
to increasing sun in the afternoon from north to south as high
pressure and subsidence from the Great Lakes continues to build
eastward. Temperatures remain rather mild/comfortable with highs
again rising into the low to mid 70s with upper 60s in the hill
towns/higher terrain.

Gradually clearing skies continues into Sunday night with
temperatures cooling in response to the drier air mass filtering
southward. Overnight lows drop into the low to mid 50s with the
hill towns and higher terrain in the upper 40s.

&&

.LONG TERM /MONDAY THROUGH WEDNESDAY/...
Similar to the short term, dry and warm conditions will start
the period as high pressure remains in control and the remnants
of Hurricane Helene spin to our south across the central
Appalachians and southern Mid-Atlantic. Eventually however,
precipitation chances look to increase by late Tuesday and
Wednesday as the next cold front approaches from the west.
Temperatures will start above normal both Monday and Tuesday
with more seasonal values expected by Wednesday thanks to
increased precipitation chances and associated cloud cover.

&&

.AVIATION /18Z THURSDAY THROUGH TUESDAY/...
Through 18z Friday...Widespread IFR/MVFR conditions with reductions
to both vsby/cigs in place with occasional rain through much of the
afternoon, as a cold front slowly sags southward across the area.
Gradual improvement to MVFR is expected late afternoon to early
evening, although there could still be some brief IFR cigs at times
mainly at KPOU/KPSF.

In wake of the cold front passage, low/mid level clouds should
gradually scour out from around KALB north to KGFL. Thicker clouds
at MVFR/VFR levels anticipated to linger at KPSF and especially
KPOU. Where breaks in the clouds occur, fog development is likely
with the best chances for IFR conditions at KGFL. Will mention MVFR
vsby for now at KALB/KPSF, although there is the potential for IFR
should more persistent breaks in the clouds develop especially at
KPSF. VFR conditions will return after 12z-13z Friday.

Winds will be variable less than 10 kt through the rest of the day,
becoming near calm tonight. Winds will then become northerly around
3-5 kt on Friday.

Outlook...

Thursday Night: Moderate Operational Impact. Chance of SHRA.
Friday to Monday: No Operational Impact. NO SIG WX. &&

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

&&

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

&&

$$

SYNOPSIS...Gitro/Speciale
NEAR TERM...Speciale
SHORT TERM...Gitro
LONG TERM...Gitro
AVIATION...JPV