000
FXUS61 KBGM 171335
AFDBGM

Area Forecast Discussion
National Weather Service Binghamton NY
935 AM EDT Fri Aug 17 2018

.SYNOPSIS...
A warm front with showers and a few thunderstorms will cross
the area this morning. Tonight a cold front will drop through
the area. Showers and thunderstorms are expected with some
storms producing heavy rain and gusty winds. Conditions turn
drier and quiet Saturday, then continues into Monday.

&&

.NEAR TERM /THROUGH SATURDAY/...

The most active period will be this afternoon and evening with
thunderstorms. Some thunderstorms will have heavy rain and
strong gusty winds. Late tonight into Saturday, a slow drying
will work southeast behind a cold front.

Showers will continue along a warm front moving into the Poconos
and Catskills this morning. Most of this rainfall is light to
moderate with top rainfall amounts under a half inch. Some minor
adjustments with the mid-morning update with rain chances and
temperatures.

An upper level trough over the Midwest will slowly move east
this period. Ahead of this is a surface low tracking northeast
from the Ohio Valley into southeast Ontario this evening. The
low will drag a surface trough through the area this afternoon
followed by a cold front tonight. Humid air over the area will
provide ample moisture for the boundaries to lift. Surface
dewpoints around 70. pwats will be 1.75 to around 2 inches much
of today into the evening. Deep warm cloud depths with narrow
CAPE. CAPE should get to around 1k with high temperatures in the
lower 80s. The best instability will be in the southeast where
fewer clouds will be and the least amount of rain this morning.
SPC has that area in a slight risk and marginal risk elsewhere.
The biggest threat will be damaging winds. With a saturated
sounding and modest cape hail should stay under an inch. Bulk
shear of around 25 kts is also modest. With the wet ground winds
will not have to be 50 mph to get trees to fall.

Given the wet ground from the inches of rain already received
this wet, thunderstorms with heavy rain will be a concern for
flash flooding. One hour flash flood guidance is mostly half to
one inch, for south central NY and NEPA. Further north 1 to 2
inches. 3 hour guidance is only 1 to 2 inches most locations and
around 2 inches far north. With slow cell movement due to winds
on the light side, flash flooding will need to be watched. The
strongest thunderstorms could cause flash flooding by themselves
but in general isolated flash flooding after multiple
thunderstorms move through this afternoon and evening.

The cold front slows as it moves through tonight. The front hits
Long Island Saturday afternoon. This is slower so delayed the
exit of showers and a few thunderstorms Saturday. Late tonight
into Saturday, rainfall amounts do not appear to be great.
Instability is lacking.

Tonight temperatures fall mostly to the upper 60s. Saturday
highs in the mid and upper 70s with slow clearing.

&&

.SHORT TERM /SATURDAY NIGHT THROUGH MONDAY/...
335 am update...

Main concerns in the short term are focused around the linger
showers and weak storms possible this weekend, mainly from the
Poconos into the southern Catskills...but potentially developing
across the rest of central NY and ne PA during the afternoon Sunday
at least for a brief period. Quiet weather expected Sunday night and
Monday.

A low amplitude weak upper trough will continue to slowly rotate ewd
across the eastern Great Lakes and Northeast Sat night through
Sunday evening with an associated lingering surface trough from the
mid-Atlantic to New England re-intensifying off the Jersey coast
during the day Sunday. The presence of at least weak-mdt cyclonic
flow aloft along with the primary sfc trough to the se and a
secondary inverted trough axis extending nnw into central NY...and 1
to 1.5 inch PWATs should prove sufficient for at least lingering rain
showers. Add in a couple hundred J/kg of ML CAPE and relatively
steep low level lapse rates and a few weak thunderstorms become
possible. There is a fairly strong inversion between 700-800mb
showing up on the 00Z NAM Sunday afternoon...which may inhibit
convection given the lack of any real strong forcing. Not overly
excited about precip chances, but given the change in the forecast
with the slower movement of the upper trough and at least a slight
chance of showers and storms...need to give attention to this
period.

Showers and storms around the area Sunday afternoon/early evening
should dissipate quickly around and just after sunset as the
boundary layer stabilizes. Expecting relatively quiet weather
through the rest of the night. Weak high pressure at the surface and
rising heights aloft, along with a drier air mass moving in on
Monday should keep quiet weather in place through the afternoon.
Will likely see afternoon cumulus develop, but with little vertical
extent and no precip expected.

Temperatures will remain on the mild side Sunday and Monday with
highs in the mid to upper 70s close to 80.

&&

.LONG TERM /MONDAY NIGHT THROUGH THURSDAY/...
335 am update...

Dry weather continues most of Monday night before the next trough
rotates through Tuesday and Wednesday. Another round of showers and
storms will accompany this system with high moisture content air
leading to additional chances for heavy rainfall as well. At this
time the system appears to be fairly progressive, which should
inhibit the flash flood potential somewhat. Conditions dry out Wed
night and into Thursday as high pressure builds back in across the
Northeast.

Temperatures will be a tad cooler than the weekend with highs only
in the lower to mid 70s...and overnight lows in the 50s and lower
60s.

&&

.AVIATION /14Z FRIDAY THROUGH TUESDAY/...
7 am Update...

Warm front with rain showers moving through the area now. Mainly
VFR but some MVFR vsbys and even brief IFR in heavy rain. This
will move east of most by 13z, then SYR by 14z, and lingering at
RME most of the morning.

Starting 16z, showers and isolated thunderstorms will develop.
Brief periods of MVFR in heavy rain is possible at all sites.
Have a tempo group for TSRA and MVFR at SYR/RME 21 to 24z. For
rest of sites no consensus on timing so went with predominant
showers and VFR.

A cold front this evening will drop conditions to MVFR with
lingering showers from NW to SE. Fuel alternate MVFR possible
late tonight in CNY.

Light and variable wind early this morning increasing to 5 to 10
kts from the south then the southwest. This evening winds
dropping to 5 kts and shifting to west.

Outlook...

Saturday morning...lingering MVFR improving to VFR.

Saturday afternoon through Monday...Primarily VFR.

Tuesday...Restrictions possible in thunderstorms.

&&

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

&&

$$
SYNOPSIS...TAC
NEAR TERM...MWG/TAC
SHORT TERM...BJT
LONG TERM...BJT
AVIATION...TAC

NWS BGM Office Area Forecast Discussion

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