-- Discussion containing changed information from previous version are highlighted. --
709
FXUS61 KBGM 181841
AFDBGM

Area Forecast Discussion
National Weather Service Binghamton NY
241 PM EDT Sat May 18 2024

.SYNOPSIS...
Rain showers this morning will become less widespread through
the day. A few thunderstorms could develop in the western
Southern Tier this afternoon but will quickly dissipate after
sunset. Partly cloudy skies tonight will lead to some valley fog
formation by Sunday Morning. Sunday is looking dry and much
warmer than today.

&&

.NEAR TERM /THROUGH SUNDAY NIGHT/...

-- Changed Discussion --
Showers and drizzle continue across areas east of I-81 as the
shortwave trough slides to the SE. Showers should start to taper
off this afternoon across this area as the trough leaves the
region. Some clearing in the western Finger Lakes has allowed
some instability to develop, diving some cellular showers across
the area, moving from NW to SE. Shear is minimal and the
instability is very shallow so severe weather is not expected.
Some brief localized heavy showers will occur but flash flooding
is not expected. Temps today will vary by about 10 degrees
across the area. Under the cloud shield across the eastern CWA,
low 60s are expected. Where clouds and rain have cleared a bit,
temps will climb into the upper 60s to near 70.

Showers dissipate across the region this evening. With the ridge
moving in, combined with light winds and a very moist boundary
layer, widespread fog is expected to develop tonight. Best
chances will be across the Twin Tiers, where the highest
moisture will be. Some fog should also develop in the western
Mohawk Valley but how far east it spreads is uncertain given the
lack of moisture in the area today. Temperatures will be in the
mid 50s across the region.

Sunday will be a very nice spring day, with temperatures
topping out in the mid to upper 70s and partly cloudy skies. A
few isolated showers may pop up across the Twin Tiers,
especially if we can get some clearing.

Sunday night should see some more patchy fog with high pressure,
light winds and small dewpoint depressions across the region.
Temperatures will be nearly identical to Saturday night, with
lows in the mid 50s.



1000AM Update...

Showers and drizzle continue across the area this morning. The
mid-level trough causing the showers is slowly moving eastward
and weakening. Expecting showers to dissipate by early afternoon
as drier air works its way in from the north. A few pop up
showers and isolated thunderstorms may develop across the
western Finger Lakes later this afternoon, especially if we can
get some clearing to occur. Storm motions with these showers are
variable and slow so moderate to heavy showers may be possible
over a localized area for for a brief period. These showers
should develop and diminish pretty quickly, so localized flash
flooding chances are very low.



630 AM update... Updated temperatures through the morning
hours as well as decreased cloud cover in the western Southern
Tier for the afternoon.

300 AM Update:

A weakening shortwave is moving through early this morning
bringing a round of light rain to most of the region. A filling
area of low pressure in western NY keeps SE flow across the
region and with sufficient low level moisture, low stratus will
persist for much of the morning into early afternoon limiting
heating. The 500 mb trough axis is swinging through so despite
the clouds, shower activity will lessen through the day. The
western Southern Tier into parts of the western Finger Lakes
will see more sun with a tongue of higher dew points nudging in
helping to destabilize the atmosphere. HREF shows around 500 to
1000 J/kg of CAPE developing by the afternoon with most models
showing some QPF so thunderstorm chances were increased west of
Elmira up towards Penn Yan. Shear will be lacking and with
little flow aloft, storms will not be moving fast. The storms
will have about 1.25 to 1.4 inches of precipitable water to work
with so heavy rain will be possible with any storms. Luckily
storms will be small and likely pulse up and down quickly so
flash flood threat is low.

Tonight, upper level ridging builds in with high pressure
nosing in from the NE. With clouds starting to scatter out late
in the afternoon into the evening, there will be enough cooling
coupled with the rain falling now to get river valley fog
development. Sunday is looking good with high pressure and
ridging remaining in place. Temperatures will warm into the mid
to upper 70s with the mostly sunny skies and ridging in place.
-- End Changed Discussion --

&&

.SHORT TERM /MONDAY THROUGH MONDAY NIGHT/...
High pressure will be over the region Sunday night with the ridge
likely to remain in place through Monday night. This will result in
winds shifting to southwesterly gradually bringing in a warmer and
slightly more humid airmass. Temperatures still look to fall into
the 50`s to around 60 at night with highs pushing 80 Monday for most
locations.

&&

.LONG TERM /TUESDAY THROUGH FRIDAY/...
The large ridge of high pressure still looks to be over the region
Tuesday before being chipped away by an approaching cold front
Wednesday. This front then looks to break down the ridge Thursday.
Enough lift and moisture looks present for at least some scattered
showers with the frontal passage. Instability during the afternoons
surface CAPE is currently modeled from about 500-1000 J/KG each
afternoon and evening so some thunderstorms will be possible as
well. Still some timing differences with the operational models and
ensemble guidance with the frontal timing. Leaned more toward the
slower ECMWF suite at this time. Given the timing differences it is
still to early to determine the potential for any strong to severe
thunderstorms.

Continued warm air advection should result in a continued warming
trend through Wednesday. Trended high temperatures through the
middle of the week closer to a blend of the 50/75th probability of
the NBM given the modeled boundary layer temperatures. Most
locations should rise well into the 80`s with a few locations close
to 90 on Wednesday. With dewpoints only around 60, heat index values
should not be much higher. Lows generally in the 60`s at night.

With the front moving through Wednesday night and Thursday some
lingering showers and thunderstorms are possible but temperatures
Thursday and Friday trend back downward again after the frontal
passage with 70`s for highs.

&&

.AVIATION /18Z SATURDAY THROUGH THURSDAY/...
Rain showers and drizzle continue across the region this
afternoon, bringing MVFR to LIFR conditions to our terminals.
BGM and ITH will see conditions lift to Fuel Alt in the next
couple of hours as the precipitation moves east of the area and
some drier air tries to work its way in from the west.

A foggy night is in store as a ridge moves overhead, bringing
light to calm winds across the area. BGM/ELM/ITH/SYR are
expected to see IFR and lower fog develop tonight. While a lot
of clearing is not expected, a very moist surface from today`s
rain will only need marginal cooling to get fog and low ceilings
to develop.

AVP has a chance at fog as well, but confidence that the
thicker fog works its way into the terminal from the valley is
low so kept overnight restrictions to MVFR. RME has been out of
the precipitation most of the day, with VFR conditions expected
through the evening. This lack of recent surface moisture will
inhibit fog development. If fog can develop, MVFR conditions are
currently expected.

All terminals should slowly become VFR by mid-morning.


Outlook...

Sunday afternoon through Wednesday...Mainly VFR. Some showers
possible by Wednesday.

&&

.BGM WATCHES/WARNINGS/ADVISORIES...
PA...None.
NY...None.

&&

$$

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