645
FXUS61 KBGM 210629
AFDBGM

Area Forecast Discussion
National Weather Service Binghamton NY
129 AM EST Thu Nov 21 2024

.SYNOPSIS...
Pattern becomes more active as a strong low pressure system
approaches our region. This system will bring much needed rain to
the region tonight with an elevation dependent snow storm Thursday
night. Low pressure system will continue to keep showers in the
forecast through the weekend.

&&

.NEAR TERM /UNTIL 6 AM THIS MORNING/...
A needed steady rainfall continues to progress eastward across
the region early this morning. Minor updates with the midnight
update on the timing and amounts by sunrise.

Some model solutions show a rapid change from rain to snow
around sunrise. However, SPC mesoanalysis still shows the 925 OC
line in the Ohio Valley. So suspect the changeover holds off
till later today for most of the region.


725 PM Update...

A swath of heavy rain will be pushing into our western counties
over the next 1 to 2 hours. Updated arrival time of the rain and
progression across the area overnight based on the latest radar
and CAMs. Forecast soundings are showing rain changing to a rain
snow mix in the early morning morning hours across Central NY
and into the Southern Tier and NE PA, with possibly a change to
all snow across the higher terrain. Not expecting much if any
accumulation with this first swath of precipitation, but cold
air does look to quickly take over and high temperatures for
tomorrow will likely occur just after midnight tonight.



525 PM Update...

Increased wind gusts for late tonight through tomorrow morning
with the passing of the cold front. Although there is some
potential for 30+ mph gusts as the front pushes through, decided
to cap winds at 25 mph for now and the bulk of the region should
see winds stay below 20 mph overnight. The best chances for the
higher end gusts will be across the higher terrain in western
Steuben County.


300 PM update...
Quiet conditions continue this afternoon and early evening
ahead of the well anticipated low pressure system. Southeast
flow has kept temperatures warm with highs in the mid to upper
50s. Temperature are expected to gradually fall this evening as
a frontal boundary pushes into our area from the west. As a
result showers also start to move into the region along side the
front. Temperatures will stay warm enough with overnight lows
ranging in low to mid 30s. This will keep rain in the forecast
for most of the night, but as cooler air moves into the region
behind the front, conditions could be cool enough for snow to
begin to mix into some of the higher elevations. Not expecting
much in terms of accumulations as the surface should remain warm
during this period.

&&

.SHORT TERM /6 AM THIS MORNING THROUGH FRIDAY NIGHT/...
300 PM update...

***Potentially High Impact Winter Storm Late Thu into Fri***

A deepening stacked low pressure system will move from the
southern Great Lakes into the northern Mid Atlantic region
Thursday into Friday. This strong system will produce high
liquid-content snow, heavy snowfall rates across the region, and
gusty winds.

The impacts of this system could be significant. The wet snow
combined with heavy rates and gusty winds could potentially lead
to downed trees/branches and powerlines. The snow, mixed with
rain could make for slushy roads in some spots and hazardous
travel conditions. The snow will also be very difficult to
shovel.

This is a very challenging forecast as the low pressure system
does not take a well-defined track, with potentially various
wobbles in direction as it moves through the Northeast US. The
low is expected to deepen, which will lead to rapid cooling of
the column. However, the amount of deepening of the low is still
uncertain, which is leading to quite a bit of uncertainty with
respect to the amount of snow. If the low doesn`t deepen as much
as expected, the thermal profiles will be warmer, which will
lead to less snow and more rain.

Broad snowfall amounts will range from 1 to 3 inches in the
valley locations, and 6 to 10 inches in the higher elevations of
the Catskills, northeast PA and Steuben county. If the low
deepens even more, snowfall amounts will be higher. There is
also the potential for some enhanced banded snowfall due to the
presence of a layer of low/mid level f-gen rotating around the
deepening surface low. We are still uncertain where this f-gen
band will set up, but it will likely lead to snowfall rates of 1
to 2 inches per hour when it does intensify and move through.

There is also the potential for gusty winds as the low deepens.
Sustained winds...variable in nature...will range from 10 to 15
mph with gusts to 20 mph in most areas...up to 30 mph along the
ridge tops and in the higher elevations.

We are still uncertain about the elevations of the change to
rain vs. snow, but we should be able to have more confidence in
this as we get closer to the event.

The low will exit to the east on Friday as some colder air
tries to move in from the north. This will interact with the
warm waters of Lake Ontario and trigger some lake
enhanced/effect snow into wrn/central NY. There doesn`t appear
to be a strong signal for significant snow accumulation later
Friday and Fri night.

&&

.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
235 PM Update

An upper level trough will be in place over the area on
Saturday,with a seasonably cold northwest flow pattern in the
forecast. This flow will allow for lake effect and enhanced rain
showers through the day, mainly for Central NY north of
Binghamton...however the rest of the area will remain mostly cloudy
and cool with breezy NW winds (10-20 mph). The NW flow pattern with
lake effect showers continues Saturday night into Sunday as well,
with 850mb temperatures dropping to around -6C. Surface temperatures
will be marginal and some wet snow flakes could certainly mix in at
times (especially overnight into Sunday morning). The lake effect
showers do begin to taper off and end later in the day. Highs over
the weekend are forecast to be in the 40s, with overnight lows in
the 30s. Some transient upper level ridging moves over the area
Sunday night into Monday, bringing a brief period of drier weather.

The next system moves in later Monday bringing some rain showers
then colder air behind it. 850mb temperatures fall back toward -5 to
-8C for the middle of next week which may bring additional lake
effect rain and snow showers in the NW flow pattern. This continues
through about Wednesday before another brief break in the weather
arrives. Temperatures are mild on Monday well into the 40s and even
lower 50s for highs. It cools back down into the 40s on Tuesday,
then mid-30s to lower 40s by next Wednesday. Overnight lows will be
in the 30s, and some 20s by Tuesday night. Overall fairly seasonable
temperatures.

&&

.AVIATION /07Z THURSDAY THROUGH MONDAY/...
MVFR conditions across all terminals as rain showers along a
cold front move across the region tonight. IFR conditions are
expected for a few hours later tonight at RME/SYR/ITH/BGM/AVP as
some snow may develop and ceilings fall with the incoming
colder airmass. ELM should remain MVFR through the morning
hours.

We should see MVFR conditions at most terminals later this
morning into the early afternoon, with RME remaining IFR. IFR
will return to most terminals this afternoon into the overnight
hours as a winter storm impacts the region. ELM will be on the
far western edge of the storm so confidence at this time was not
high enough to include IFR conditions here.


Outlook...

Thursday night through Friday...Restrictions likely with a
wintry mix of rain and snow or just snow for most terminals. SYR
and RME are expected to remain rain during this time.

Saturday...Continued possible restrictions in rain and snow
showers, especially Central NY.

Sunday...Gradual improvement. VFR probable for AVP with MVFR
expected elsewhere. Mixed rain/snow showers far northern areas.

Monday... Another approaching low pressure system could bring
possible restrictions.

&&

.BGM WATCHES/WARNINGS/ADVISORIES...
PA...Winter Storm Watch from this afternoon through Friday
     afternoon for PAZ038>040-043-044-047-048-072.
NY...Winter Storm Watch from this afternoon through Friday
     afternoon for NYZ022>025-044>046-055>057-062.

&&

$$

SYNOPSIS...ES/JTC
NEAR TERM...ES/JTC/MPK/MWG
SHORT TERM...BJT
LONG TERM...MJM
AVIATION...JTC

NWS BGM Office Area Forecast Discussion