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fxus61 kbgm 221134 
afdbgm

Area forecast discussion
National Weather Service Binghamton New York
634 am EST Mon Jan 22 2018

Synopsis...
temperatures will remain mild, through Tuesday, along with
periods of rain, along and ahead of an approaching cold front.
Readings will turn colder, for the mid week period, with the
chance for lake effect snow showers and flurries.

&&

Near term /through Tuesday/...
315 am update... areas of locally dense fog, along with patchy
light rain/drizzle, prevail this morning across cny/nepa. Warm
advection forcing is the main driver for sporadic light
rain/drizzle. Relatively warm, moist air is creating foggy
conditions, as it rides over the ripening snow pack. We see
relatively little change in this pattern through much of the day
Monday, other than perhaps a slight uptick in rainfall over our
northern zones this afternoon, as a short-wave glides across
the region and briefly enhances forced ascent.

Readings remain near or just above freezing at this time over
parts of Oneida, Madison, Chenango, and Otsego counties.
However, as boundary layer warm advection continues, we expect a
slow upward trend in temperatures, and a lessening threat of any
freezing rain/drizzle with time. We currently have a Special
Weather Statement out through about daybreak to address any
isolated icy conditions in these areas.

Tonight and Tuesday, as the main cyclone tracks from the central
Great Lakes region up through the St. Lawrence Valley, a
trailing cold front will approach, and then swing across
cny/nepa. The main shot of rain for US will come just ahead of,
and along this front, primarily late tonight and Tuesday
morning. Our latest guidance would suggest rainfall amounts
during this period of generally 0.5-0.75" from about the I-81
corridor eastward, with 0.25-0.5" back to the west. Current
thinking is that these amounts, combined with snowmelt runoff,
would be insufficient, in and of themselves, to cause
significant Hydro issues. Ice behavior, though, remains
uncertain. For more specifics, please refer to the hydrology
section below.

Steadier rain should taper off to more scattered showers Tuesday
afternoon, behind the front. After midday highs in the 40s to
near 50, temperatures may begin to fall off during the
afternoon.

&&

Short term /Tuesday night through Wednesday/...
340 am update...

Upper level heights fall as a broad trough moves into the northeast
US. A strong surface low in the St. Lawrence Valley Tuesday evening
will move east to New Brunswick and drag a cold front through our
area. This will change precipitation from rain to snow in the
evening. Deep moisture with the front will quickly exit leaving some
weak lake effect snow showers with a northwest flow Wednesday during the
day. Saturated moisture levels drop below 5k ft but the dendrite
zone is in this moisture level. Snowfall amounts will be up to 2
inches for Syracuse and Utica and locations further north Tuesday
night. Amounts Wednesday will be lighter and mostly an inch or less.
Maybe some of the higher terrain in the eastern Finger Lakes to the
northern Susquehanna region could get 2 inches.

Temperatures fall into the 20s Tuesday night then recover about 5
degrees Wednesday. Wednesday will be breezy with weak cold air
advection.

&&

Long term /Wednesday night through Sunday/...
345 am update...
little change. Weak lake effect Wednesday night and Thursday
with a short fetch and a north-northwest flow into The Finger lakes. Amounts
will be very light. Still weak cold air advection. Cooler temperatures than
normal into Thursday night then on the back side of the surface
high and upper level ridge it becomes above normal. High 30s
Friday and 40s Saturday and Sunday. Rain for Sunday and Sunday
night with an occluded front.

Previous discussion...
large high pressure builds in for the end of the week. This will
bring US generally dry weather in the period, with seasonable
days, but chilly nights as the temps tumble under clear skies.
By Friday, Ridge slides east and warm advections begins with the
upper heights build. Precipitation will hold off through the
period, although clouds will increase on Saturday as moisture
streams up from the Gulf along the backside of the high and
into the Great Lakes.

&&

Aviation /12z Monday through Friday/...
12z update... widespread restrictive conditions will persist
throughout the valid taf period, with plenty of low-level
moisture bringing continuous low clouds, along with occasional
rain, drizzle, and fog.

At kbgm, kith, kelm, and kavp, conditions will vary between fuel
alternate required and below alternate minimums. At kbgm,
field minimums will still be challenged, at times.

At ksyr and krme, conditions will mostly reside within the fuel
alternate required category, but periods of IFR can also be
anticipated, especially at krme.

Surface winds will generally average 5 kt or less through the
morning, but will gradually increase to 5-12 kt out of the southeast-S
this afternoon and tonight.

Outlook...

Tuesday...flight category reductions continue under periods of
rain.

Tuesday night through Wednesday...possible continuation of
flight category reductions and a chance of shsn.

Thursday and Friday...VFR under high pressure.

&&

Hydrology...
350 am update...

Localized flooding due to ice jams is possible mainly Monday
night through Tuesday night. Widespread rain will develop
across the region late Monday night and Tuesday with amounts
ranging from a quarter to three quarters of an inch...and
temperatures will rise into the low 40s today, drop little
tonight then rise to 45 to 50 Tuesday. Also, the snow pack
water equivalent is generally around 1 inch or less. So, the
combination of rain and snowmelt runoff will cause rivers to
rise which may break up the ice currently in place. This may
result in jams downstream. The most rainfall is expected across
the Susquehanna River basin in northeast PA and the Delaware
basin in New York and PA. However, ice jams can occur along any rivers
in our area. Will continue to monitor the situation and the
possibility of a Flood Watch.

So far the rivers are steady with little runoff due to the light
rainfall and little snow melt. This will start to change late
today as the snow further ripens and the warm front lifts
through cny with a tenth or two of rain. Better runoff will
occur late tonight into Tuesday. River forecasts for a few
headwaters of the upper Susquehanna and Delaware rivers get
close to flood stage late Tuesday or Tuesday night.

&&

Bgm watches/warnings/advisories...
PA...none.
New York...none.

&&

$$
Synopsis...mlj
near term...mlj

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