Union, New York 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

534
FXUS61 KBGM 211456
AFDBGM

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

.SYNOPSIS...
A strong low pressure system develops near Long Island later
today and rotates through the region on Friday bringing more
rain and snow. This low looks to linger near New England through
the weekend. Another cold front then follows with another
chance of rain and snow showers early next week.

&&

.NEAR TERM /THROUGH FRIDAY/...

930 AM Update...

Brief intermission holds over the western portion of our region
with light showers continuing over the eastern portion. Overall
temperatures are a couple degrees warmer than previously
forecasted. Therefore made minor changes blending in current
temperatures and dew points observations while also bumping up
todays highs. Also made tweaks to sky grids to capture a break
in the clouds over the central southern tier and eastern finger
lakes region. No other changes needed at this time.

630 AM Update...

A bit of wet snow did mix in at our office 1,600 feet elevation.
This should occur at similar elevations further east with this
first round of precipitation. Otherwise, only minor changes with
the sunrise update. Previous discussion below.

330 AM Update...

A rather complex winter storm is ongoing across the region this
morning. A band of rainfall is moving eastward and should exit
around sunrise or so. This should bring a short break today
before an additional surface low develops late this afternoon
near Long Island. This low pressure system will then retrograde
northwest and loop through our region under an upper level
trough.

Considerable lift near and west of the low should start to
redevelop rainfall across the region this afternoon from east to
west. Slightly drier air will also start to advect into the
region this morning. Dynamical and evaporational cooling
processes should allow for rain to change to snow from the
higher elevations to the valleys as precipitation falls. As the
low moves further northwest into our region precipitation looks
fairly widespread tonight.

Later this evening and overnight a look at 700 MB modeled FGEN
shows very strong signals for banding moving into Sullivan and
Pike county that basically tracks along route 17/ I-86 through
the overnight toward Broome county.Snowfall rates under the band
have the potential to be 1-3+ inches per hour for several
hours. Some uncertainity is still present in the exact location
of the banding but guidance from WPC and Hi-Res guidance favors
these locations at this time. The banding signal becomes more
diffuse toward sunrise with weaker bands likely rotating toward
Ithaca and Cortland and further southwest into Bradford PA.

Snowfall ratios look to vary quite a bit as well. With lighter
precipitation and a warm ground initially values may be under
5:1. This is particularly true in valley locations that take
longer to changeover. When heavier snowfall rates occur we should
be able to get a more typical of a 10:1 ratio. This shows on
model soundings as favorable snow growth in the -10 to 20C
layer, steep mid- level lapse rates and plenty of Omega.
Snowfall totals look to be maximized at higher elevations under
the intense bands. Amounts of over a foot to locally 18 inches
are not out of the question in the warning with valley locations
getting several inches.

More uncertainity is present for the heavy precipitation to
reach the remaining counties still under a winter storm watch in
the Finger Lakes/Steuben county eastward to Cortland and
Cooperstown. Valley locations could get just light precipitation
resulting in only light accumulations leading to sharp cutoffs.

Steady snowfall should continue to around noon in NE PA.
Precipitation then becomes more showery later Friday. The loss
of the precipitation rates should allow temperatures to rise
from around freezing for lows well into the 30`s. Areas that
see much less precipitation such as Syracuse may not fall below
the mid 30`s and get well into the 40`s Friday.

&&

.SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY NIGHT/...
300 AM update...

The center of the low pressure system that brought the winter
storm to the region will slowly slide to the east Friday night.
Northerly flow will push a marginally dry slot into the area.
There will be some lingering snow showers across the region, but
showers should dissipate as the night progresses. Lows will fall
into the upper 20s to low 30s across the region.

Saturday, the upper level trough that has been mostly stationary
and spinning over the region will finally open up and speed up
its progression to the east. This will bring NW flow across the
region and continue to advect in cool air from Canada. Lake
effect precipitation is expected to develop late Saturday
morning into the afternoon. An upstream connection to the
Georgian Bay on Lake Huron will enhance lake effect
precipitation across the northern Finger lakes into the Mohawk
Valley Saturday evening into Sunday morning. Temperatures will
be warm enough for most of the precipitation to fall as rain.
Higher elevations in the Finger Lakes and south of the Mohawk
valley should see snow mix in Saturday night, but accumulations
are not expected at this time. Temps on Saturday will be in
the low to mid 40s across the region.

Lake effect showers will continue through Saturday night into
Sunday afternoon. A ridge will build into the area late Sunday
afternoon, which will cut off the lake effect process and bring
cool and quiet weather to the region Sunday night. All told,
up to 0.25in of rain could fall, centered on an area from
Seneca to Oneida county. Temps on Sunday will once again be in
the 40s, with overnight lows in the upper 20s to low 30s.

&&

.LONG TERM /MONDAY THROUGH WEDNESDAY/...
315 AM Update

Monday looks to see high pressure sitting overhead, bringing
quiet and and seasonable temps to the region. A clipper system
looks to stream across the Great Lakes and impact the region
Monday night into Tuesday. Timing and location of said system is
still uncertain, but current thinking is a warm airmass ahead
of the system will allow rain showers to fall across the area
Monday night into Tuesday morning. Cold air will filter in
behind the clipper, changing precip over to snow or a rain/snow
mix Tuesday afternoon. Lake effect showers will continue into
Wednesday with valleys seeing rain or a rain snow mix and higher
elevations seeing mostly snow showers.

&&

.AVIATION /15Z THURSDAY THROUGH MONDAY/...
Very tricky aviation forecast today as guidance is not handling
this system extremely well. The rain shield has moved farther
east than forecast, bringing VFR conditions to BGM and ITH. ITH
should stay VFR through the morning, while BGM should fall back
to MVFR in the next few hours, but confidence in this is low.
Fog has moved into ELM, bringing IFR ceilings to the terminal.
This should remain for a couple hours where ceilings will lift
to MVFR mid morning through the afternoon. SYR should remain
MVFR through the morning while RME sees IFR ceilings.

Precipitation will increase in coverage and strength later this
afternoon as the winter storm impacting the region begins to
strengthen. IFR/LIFR conditions are expected to develop at
all terminals later this afternoon/evening with snow falling at
ITH/ELM/BGM/AVP by late this afternoon/early evening. RME and
SYR should remain all rain, although periods of snow cannot be
ruled out.

Outlook...

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 4 PM EST this afternoon through Friday
     afternoon for PAZ038.
     Winter Storm Warning from 4 PM this afternoon to 4 PM EST
     Friday for PAZ039-040-043-044-047-048-072.
NY...Winter Storm Watch from 4 PM EST this afternoon through Friday
     afternoon for NYZ022>025-036-044>046-055.
     Winter Storm Warning from 4 PM this afternoon to 4 PM EST
     Friday for NYZ056-057-062.

&&

$$

SYNOPSIS...MWG
NEAR TERM...ES/MWG
SHORT TERM...JTC
LONG TERM...JTC
AVIATION...JTC