344
FXUS61 KBGM 061807
AFDBGM

Area Forecast Discussion
National Weather Service Binghamton NY
207 PM EDT Sat Jul 6 2024

.SYNOPSIS...
A few isolated showers and thunderstorms will move across
Central NY into the early evening hours, otherwise partly sunny
and warm weather expected for the rest of today. Temperatures
will still be warm through the weekend but it will feel less
muggy with the lower humidity, especially on Sunday. Heat
continues into next week with chances for rain and thunderstorms
returning by mid week.

&&

.NEAR TERM /THROUGH SUNDAY/...
1240 PM Update...

Forecast is on track. Minimal changes with this update. GOES
East visible satellite loop shows scattered to broken (35-60%)
cumulus cloud cover out there this afternoon. Had an extremely
isolated shower or two pop up, but in general there is not much,
if any trigger out there to get convection going thus far.

There is a lake breeze convergence boundary over western NY
which may propagate east later this afternoon and act as a
catalyst for isolated to sct`d showers/t`storms over portions of
Central NY. Temperatures are in the low to mid-80s currently,
with sfc dew points dropping back a touch, now between 65-72F,
which is up to 5 degrees lower than 24 hours ago (based on 1240
PM NY mesonet data).

MLCAPE is 300-600 J/Kg currently with LIs between -1 and -3 on
the SPC mesoanalysis. Effective layer shear is impressive at
40-55 kts currently, but areal average soundings from the 15z
HRRR are showing dry air in the 750-550mb layer which is choking
off any showers that reach this level so far. The HRRR keeps
this dry layer, and a weak thermal cap around 575mb in place
into the late afternoon hours...and yet it does allow for a few
thunderstorms to develop. Overall, sounding data shows most
parameters unfavorable for severe storms this afternoon...again
owing to just too much dry air, and weak mid/upper level lapse
rates. Equilibrium levels are low, especially for the mixed
layer parcels, only reaching 20k ft agl...and 25k ft agl for
surface based parcels. Will continue to monitor, but for now
left slight chance to low end chance PoPs in the forecast across
Central NY for the late afternoon & early evening.

835 AM Update...

The valley fog is quickly dissipating now, with some lingering
convective debris clouds over the Catskills. The rain has exited
the area and it should remain dry until at least 2-3 PM.

Otherwise, it is mostly sunny across the region this morning.
An additional area of scattered mid level clouds will move into
the area this afternoon in association with a weak shortwave.
Took a blend of the HRRR and 06z 3km NAM to update, and make
minor tweaks to PoPs this afternoon and evening. Depending on
how much mid level dry air moves into the area, there still
appears to be a chance for isolated t`storms to develop over
portions of CNY between about 3 PM to 9 PM today; most of the
activity stays just north of the Southern Tier, but can`t rule
out a stray shower/storm even here.

Overall, the forecast remains well on track with not many
changes needed at this time.

630 AM Update...

Storms have moved off to the east with less shower activity
behind it so chances of precipitation were greatly reduced
through the rest of the morning. It is still looking like there
will be enough instability this afternoon for a few isolated to
scattered thunderstorms across the Finger Lakes into CNY.

315 AM Update...

Showers and thunderstorms have developed across east central PA
early this morning and will be moving into the Wyoming Valley
through sunrise. Mesoanalysis shows a decent amount of most
unstable CAPE (2000-3000 J/kg) extending from the Chesapeake Bay
up into PA helping to fuel these storms. 0-6 km shear with
these storms is only around 20 to 25 knots though given the high
CAPE severe storms are possible with strong winds and hail.
Forecast soundings dont show too much cin and given the
temperature at AVP was 77 degrees at 1 am it seems reasonable
that some of the winds could punch through to the surface with
any stronger downburst. So far despite tall cloud tops, storms
have struggled to get any deep cores in order to get enough
precipitation loading to get a microburst or downburst.
Precipitable water values are currently over 1.5 inches with
deep warm cloud depths so heavy rainfall rates are likely with
any storm. Right now the storms are moving at a good pace and
there has not been any training so far as of 3 am.

The surface trough responsible for triggering these showers and
thunderstorms will be moving east this morning with dry air
advecting in. The dry air can be seen on water vapor imagery in
central PA and as that moves in, day time heating will be able
to mix some of it down with dew points falling this afternoon.
Soil moisture will likely be fairly high with the rainfall this
morning so areas that see more than a quarter inch of rain may
take more time to dry out. The Finger Lakes into CNY will have a
500 mb shortwave pass through this afternoon coupled with a 250
mb jet streak with the HREF showing between 400 and 900 J/kg of
surface based CAPE developing so a few isolated thunderstorms
are likely. The lack of good instability will limit the severe
potential with the afternoon storms but given the high shear,
higher lifted condensation levels, and steep low level lapse
rates, a small potential exist for severe wind gusts if any
storm can get a deep enough core. The dry air in the mid levels
and skinny cape depicted in forecast soundings will really lead
to dry air entrainment with the storms so many will struggle to
develop much above 15,000 to 20,000 feet.

Once the shortwave is through this afternoon, ridging builds
back in with flow aloft weakening and the 250 mb jet retreating
northward. Dry air in the mid levels remains with surface high
pressure building in so temperatures remain warm but mixing will
help drop dew points into the mid to low 60s.

&&

.SHORT TERM /SUNDAY NIGHT THROUGH MONDAY NIGHT/...
High pressure starts to build into the region Saturday night
shifting any chance of showers and thunderstorms east of the region.
With the high pressure system overhead Sunday looks quiet as well.
However, heat and humidity will start to increase on the backside of
the high. Enough moisture looks to be in place to where a shower or
thunderstorm can not be ruled out Monday afternoon or night.

Temperatures overall Sunday look slightly cooler ranging from the
60`s to the 80`s. However, temperatures look to warm a few degrees
Monday with slightly higher humidity as well. Many valley locations
have the potential to hit 90 degrees, coupled with the humidity
afternoon heat index values of 95-100 are possible Monday.

&&

.LONG TERM /TUESDAY THROUGH FRIDAY/...
Another cold front looks to push toward the region for our next
chance of showers and thunderstorms later Tuesday through Wednesday.
Temperatures should trend a bit cooler as well. PW values are still
forecasted to surge to around 2 inches later Tuesday, introducing a
localized small stream and urban flood concern from locally heavy
downpours.

A more concerning pattern sets up for the middle and back half of
the week. Upper level ridging off the east coast looks to slow the
movement of the front possibly even stalling out. The track of
Beryl has trended northeast enough to where current NHC
projections have it going into the Southern Plains early next
week. Ensemble guidance shows the potential for Beryl to track
further northeast along the previously mentioned cold front into
the Ohio Valley, Great Lakes and the Mid Atlantic regions by
Thursday. This would enhance tropical moisture for heavy
rainfall and potential localized flooding if it tracks close
enough to the region. Any threats for gusty winds or isolated
tornadoes are also dependent on the track, which is still
highly uncertain.

&&

.AVIATION /18Z SATURDAY THROUGH THURSDAY/...

200 PM Update

Mainly VFR conditions persist across the region through the taf
period. However, there is a chance for an isolated thunderstorm
or two in vicinity of SYR and RME as a surface convergence
boundary moves west to east. Therefore, included a PROB30 group
at these two sites from 19-23z this afternoon/evening. For the
other taf sites, it is very likely to remain dry, with chances
for any showers or t`storms only at 10-20% through sunset.

Tonight, high pressure and clear skies lead to fog developing
again mainly at ELM as they are likely to drop below their cross
over temperature during the predawn hours. Included a period of
Below Alternate Minimum restrictions in fog for ELM between
about 08-11z. The fog should lift and scatter out quickly by
mid-morning...with a return to VFR conditions areawide for the
rest of Sunday.

Outlook...

Sunday Afternoon and Monday...Mainly VFR.

Tuesday Through Thursday...Showers and thunderstorms possible,
with associated restrictions.

&&

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

&&

$$

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