Area Forecast Discussion
Issued by NWS Binghamton, NY

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FXUS61 KBGM 191807

Area Forecast Discussion
National Weather Service Binghamton NY
207 PM EDT Mon Mar 19 2018

High pressure will provide mainly clear skies but cold
temperatures through tonight. Although we`re still watching an
east coast storm, in the Tuesday to Wednesday time frame,
present indications are that any accumulating snow, will be
confined to the Poconos and Catskills.


1000 AM Update...Near term forecast remains on track, only made
minor tweaks to sky cover and temperatures for today and
tonight. Bumped temperatures up a few degrees for this afternoon
over the valleys in the southern tier of NY and NE PA, where
full sunshine should help to boost temperatures into the mid-30s
to lower 40s....could even see a few mid-40s in the lower
Wyoming Valley region near Wilkes-Barre. The only clouds noted
on the latest visible satellite imagery are over Luzerne/Pike
counties and these should slowly drift south, out of our area by
midday. Otherwise am expecting sunny skies into the afternoon.
Skies remain mostly clear this evening, before high clouds
gradually increase from the south overnight. Lows will be quite
cold again, dropping into the single digits and teens in Central
NY...with teens and lower 20s for NE PA.

Still keeping a very close eye on the storm system for Tuesday
afternoon through Wednesday. We will be evaluating the new 12z
model guidance and will have an update on this system with the
afternoon package.

     Previous Discussion Below...

Early this morning a shallow layer of moisture is moving through
the region behind a weak surface boundary. By mid morning skies
are expected to become mostly sunny as high pressure in eastern
Canada builds south across the area. Temperatures will remain
cool even with plenty of sunshine. Highs in the northern
forecast area will range in the middle to upper 20s with the
southern tier and northeast Pennsylvania in the lower to middle
30s but the Wyoming Valley near 40.

Tonight, high pressure over eastern Canada will keep its
influence over the area with mainly clear skies. High clouds
will increase over northeast Pennsylvania late tonight. Lows
will fall into the 5 to 15 degrees range in central New York and
15 to 20 over northeast Pennsylvania.

On Tuesday morning the initial low forming over the southeast
will lift quickly out to sea as it moves off the North Carolina
coast. By late day as the upper level trough deepens over the
southeast another low will develop under the upper level
feature in the Tennessee Valley as a secondary low develops
again near coastal North Carolina. The NAM/GFS/ECMWF keep the
area dry through 00Z Wed. There will continue to be a very tight
moisture gradient on the north side of the system with cold/dry
Canadian high pressure and continued northeast surface flow.
Will keep just slight chance pops in the far southeast forecast
area Tuesday afternoon. Highs will range in the 30s.


420 AM Update...
Main forecast challenge remains evolution of a complicated
coastal system. While odds are it misses the majority of the
area, uncertainty is rearing its ugly head even more, especially
greater Hazleton/Wilkes-Barre/Scranton to Monticello areas.

The main players will be a southern stream wave of low pressure
now in the Southern Plains, a northern stream upper trough which
will attempt to dig in behind the southern wave as it translates
to the Midatlantic Coast, and a cold yet very dry air mass from
high pressure building across Ontario into Quebec with time.
ECMWF has started trending further north with shield of
precipitation during the last couple of runs, meanwhile the 00Z
NAM - which has had a pretty good track record this season -
actually completely misses the area along with a great majority
of GFS ensemble members. SREF ensemble output, however, brings
a surprisingly broad swath of snow to a large part of our area.
SREF often overdoes precipitation especially in terms of
coverage, but the range and spread of magnitude is unusually
large at this time, with mean values of many inches of snow
extending well inland.

To summarize, while the lately well-performing NAM completely
misses us, the operational GFS-ECMWF-GEM bring outer edge of
snow into our Northeast PA zones, and perhaps to southern
Catskills. The SREF if nothing else highlights the fact that
there is still uncertainty. Meteorologically, the models
regardless of precipitation placement have us in a very
unfavorable location for jet support - left entrance region
Tuesday night into Wednesday - and the low level flow of air in
keeps a northern trajectory the whole time, feeding in very dry
air from the Canadian high. So there is not a lot of support;
it may turn out to be more virga than anything else.

For now, we have stepped up snow chances in the Wyoming Valley-
Poconos-Catskills areas Tuesday night into Wednesday, with about
1-3 inches snow accumulation south of the Scranton to
Monticello line, especially towards Hazleton. Hopefully, upcoming
model runs will bring more clarity to this situation. This does
have the look of a system in which there could be a very sharp
gradient between no snow at all, and a significant accumulation.
That line could very well be still south of the our area, where
better support will exist. Anyone with travel plans, especially
heading south and east, will want to keep an eye on this one.


215 pm update... Overall, a quiet period is in store, behind the
prior east coast storm.

From Thursday into Saturday, a narrow short-wave ridge at
upper-levels of the atmosphere will move over CNY/NEPA, while
high pressure at the surface noses down from eastern Canada.
This will bring dry weather, with a continuation of below normal
temperatures. Night-time lows will be cold, mainly in the
teens-mid 20s, with afternoon highs mostly in the 30s-lower

Models begin to diverge towards the end of the weekend, with
some suggestions that a frontal zone could bring some light
precipitation. For now, we`ve indicated a chance for light rain
or snow on Sunday.


High pressure is keeping clear skies over the entire area this
afternoon and evening. High clouds, above 20k ft agl begin to
develop late tonight, after 20/09-12z, spreading from south to
north over the area. The clouds gradually lower and thicken over
the southern and central terminals later Tuesday morning. After
20/15-18z an 8-12k ft agl CIG is expected to develop at
KAVP....with only thin cirrus making it north to KSYR and KRME
prior to 20/18z.

Northerly winds at 5 to 10 knots today becoming light and
variable again this evening. Expect northeast winds less than 10
kts later tonight into Tuesday morning.


Tuesday Afternoon...VFR through the daylight hours.

Tuesday night through Wednesday evening...Mainly VFR at NY
terminals. Snow likely with associated restrictions at KAVP.

Wednesday night through Saturday...Mainly VFR.




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