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Area Forecast Discussion (AFD)

Issued by Binghamton, NY (BGM)

FXUS61 KBGM 242357

National Weather Service Binghamton NY
757 PM EDT Mon Jun 24 2019

A frontal system will pass through the area tonight into early 
Tuesday with periods of showers and embedded thunderstorms. 
Locally heavy rainfall is possible. While dry much of the time 
for the rest of the week, other weak disturbances will skim by 
the area yielding isolated to scattered showers and thunderstorms.


Expect partly sunny skies this evening, with a light shower or
sprinkle possible. Mild with temperatures well into the 70s and
light winds.

Not much change to the near term portion of the forecast as the
main concern is still for isolated heavy rain late tonight into
early Tuesday as a fast moving frontal system advances with a 
narrow axis of high precipitable water values.

Upstream a negatively-tilted wave aloft will force an occluded 
front into the region overnight. Despite the initially dry 
retreating air mass, models are in agreement that the upper wave
is successfully tapping Gulf moisture and it will pool together
a narrow axis of anomalously high precipitable water (pwat) 
values around 2 inches. The good thing is that we have had a few
dry days, and the occluding front/high Pwat values will carry 
through late tonight into early Tuesday morning when diurnal 
energy is at a minimum. Best chance for rain will be between
about 2 AM to 9 AM Tuesday, moving from west to east.

Most areas will have no problem handling the average of a third
to two-thirds of an inch of rain. However, for a brief time 
things may line up for a possible small window of training- 
backbuilding of embedded convective cells somewhere within our 
area. Rainfall will be very efficient in the nearly moist- 
adiabatic air mass and warm cloud depths will get to around 
12-13 kft agl. Thus we cannot rule out isolated heavy rain and 
localized flooding, even though the vast majority of the area 
should be fine. There are some pockets of our area that if 
receiving more than 1 inch of rain in a short period (1 hour), 
could experience minor issues. With the ample cloud cover and 
moisture, it will be a muggy night with lows in the 60s.

After about 8-10 AM Tuesday most rain will start heading east 
of I-81, though there could still be lingering spotty showers. 
Westerly winds will pick up a bit (8-15 mph), though being an 
occluded front there will be very little if any shallow cool 
air advection behind it. Dew points really do not fall much
either, holding in the low to mid 60s through the day. Highs 
will again be right around climatology in the upper 70s to low 
80s, and clouds will generally decrease as the day carries on.

Tuesday night: Will be mainly dry, under partly cloudy skies
with decreasing winds (light and variable after midnight) as
surface ridging builds overhead. Will need to watch as some
patchy river valley fog may form, but not enough confidence to
put in the forecast at this time. Slightly cooler with lows in
the upper 50s to lower 60s.


Vertically stacked upper low sits near James Bay and moves
little in the short term. The forecast area sits in the southern
base of the broad trough. A short wave will rotate through the 
trough on Thursday adding a bit of instability and increasing
the chance for shower and thunderstorms, especially over the NY
counties. That wave will pass Thursday evening but with yet 
another weaker wave rotating through on Thursday, perhaps bring 
a slight chance then. Most of the time will be dry however.

Temperatures will be near normal with the days slightly cooler,
and the nights slightly warmer with clouds.


Dry weather returns for Thursday night into Friday as upper
ridge builds and a surface high slides into the area. Weather
still looks shaky for the weekend as the old upper low slides 
into Maine. Models are a bit further east with the upper low but
keep a surface trough back to the southwest over New England 
and into NY. This will bring the chance for showers and 
thunderstorms back into the forecast. All surrounding offices 
have continued with high chance pops for the weekend, so will go
with that with the highest chance on Saturday with peak heating
and the surface trough in the vicinity. Sunday, some weak 
surface ridging arrives despite the upper low over New England.


VFR conditions will continue across the terminals through 06Z.
Late tonight a surface occlusion will cross the region bringing
MVFR/Alternate required showers. Thunderstorms are possible but
not included in TAF due too limited areal coverage. Behind the
boundary MVFR/Alternate Required ceilings will linger into the 
mid/late morning when VFR conditions will develop with SCT/BKN 
ceilings around 4K feet.

Surface winds E/SE around 5-8 knots shifting to the southwest
early to mid morning then westerly by late morning at 10 knots 
with some sites gusting to 18 knots during the afternoon.


Tuesday night through Wednesday morning...Mainly VFR.

Wednesday afternoon and Wednesday evening...Another passing 
disturbance with chance of showers-thunder/brief restrictions.

Wednesday night through midday Friday...Mainly VFR.

Friday afternoon through Saturday...Increasing chances for 
showers-thunderstorms and restrictions as a wave approaches.