Scientific Forecaster Discussion
fxus61 kbgm 221430
Area forecast discussion
National Weather Service Binghamton New York
930 am EST Fri Nov 22 2019
a cold front will sweep through the area this morning bringing a
period of rain showers, gradually mixing with and changing to
scattered lake effect snow showers this afternoon. Starting out
mild this morning, then turning much colder and windy late in
the day. High pressure then builds in for cold and dry weather
tonight and Saturday. Watching a system which could bring a
brief wintry mix to the area Saturday night into Sunday.
Near term /through Saturday/...
930 am update...made very minor changes to the forecast to
reflect latest trends, mainly with hourly temperatures. Still
expecting rain showers to mix with and eventually change over to
snow showers by this afternoon as a cold front quickly Ushers
in cooler air. Temperatures across most of the area as of this
update are in the 40s to near 50. Portions of western Steuben
County have already dropped to the lower to mid 30s. By late
afternoon, most of the area will be in the 30s.
645 am update...light rain is now developing across the region
just along and ahead of the cold front. Expect a 3-5 hour period
of steady light to moderate rain this morning, as the front
drops northwest to southeast across the region. Forecast remains on track
with only very minor timing adjustments for this update.
Rainfall amounts will likely range from 0.10 to 0.25 inches
across much of the region. Still expecting some scattered snow
showers to develop late this afternoon...and as temperatures
fall below freezing toward or just after sunset wet roads may
become icy and/or snow covered locally.
Previous discussion below...
Main focus in the near term is on a cold front
that will push through the region this morning, bringing a
period of rain showers, changing to snow showers and gusty
winds. Turning much cooler later today and tonight.
Today: cold front approaches our western zones by daybreak, reaching
I-81 in cny by mid to late morning...then clearing our southeast counties
by midday or early afternoon. Expect a period of light to moderate
rain showers along and just behind this front. Went with high end
likely to low end categorical pops for a few hours as the front
moves through, but quantitative precipitation forecast will be low...generally under a quarter inch.
Temperatures start off mild this morning, well into the 40s, but
fall through the 30s by afternoon. 850mb temperatures fall to around
-10c by late afternoon as strong cold air advection takes hold.
BUFKIT soundings show steep low level lapse rates and even a small
amount (<50 j/kg) of cape this afternoon. This will make for gusty
west-northwest winds, likely sustained 15-25 mph, with gusts up to
around 40 mph...at this time the thinking is wind speeds will be
just below advisory levels for most locations. Will mention the
gusty winds in the severe weather potential statement for now, and continue to monitor trends.
Along with the gusty winds there will be scattered snow showers
coming off of Lake Ontario and perhaps The Finger lakes into central
New York late this afternoon and into the evening hours...looking like a
310-320 degree flow. Any snow accumulations will be light (< 1/2
inch) and mainly across the hilltops of central New York.
Tonight: scattered lake effect snow showers linger in the evening,
first on a 320 flow...but it backs to westerly overnight as a ridge
of high pressure builds over the region. Outside of the snow
showers/flurries it will be partly cloudy to start, with clearing
overnight. Any snow accumulations should again be under 1 inch...and
only in narrow, favored lake effect bands. Winds diminish rather
quickly during the evening, dropping under 10 mph after midnight.
Colder with lows in the 20s.
Saturday: surface high pressure in place across the mid-Atlantic
slowly shifts offshore...but should keep our weather dry during the
daylight hours. Lingering lake effect clouds up across Oneida County
in the early morning, otherwise mostly sunny areawide. High clouds
could move in from the south/southwest late in the afternoon. Winds
turn west-southwest 5 to 10 mph. Seasonable temperatures with highs
Short term /Saturday night through Sunday/...
this period features a developing coastal storm that originates
from the central and Southern Plains today. The upper level low
/ trough associated with this system reaches around Indiana by
00z Sunday as a low level cyclone develops from the central
Appalachians south to the eastern NC, Georgia and eastern SC. Ahead
of this upper level low and associated trough the low-level
winds turn south through a deep layer and advect plenty of
moisture northward toward New York and PA. The moisture will be rising
isentropically and hence saturating and producing precipitation.
As the precipitation approaches northeast PA and central New York
Sunday evening, temperatures will be marginal for rain, snow,
and freezing rain. This system is projected to become a pretty
significant coastal storm by the time it reaches off the New
England coast. If it was a few degrees cooler, this could be a
moderate snow event for our southern and eastern areas with much
heavier snows east of US. Temperatures are projected to be too
warm though. Stay tuned.
Used the top down tool in forecast builder to assist with
precipitation type off of the nbm given the uncertainities with this
system. Looking at total snowfall from several models and wpc
probabilities of exceeding 2" of snowfall it appears that the
Catskills have the best shot in our forecast area. Measurable
freezing rain of a few hundredths will be possible over a large
area of northeast PA and south central New York except valleys. So we
will have a mixed bag of mainly light precipitation beginning
Saturday evening and lasting through Sunday morning before
ending by Sunday evening. At this point it appears most areas
see less than 1" of snow at best and 1-2" possible Catskills
into higher Poconos. It is looking like a potential minimal
advisory event in the south central New York and northeast PA because
of freezing rain potential so we will continue to mention in severe weather potential statement
for now. We also will put a one slide briefing out to cover
this minor event.
Long term /Sunday night through Thursday/...
for Sunday night to Monday, a ridge of high pressure slides to the
east with fair weather and moderating temperatures. Southerly flow
continues through Tuesday in advance of the next significant weather
system with mild temperatures. Highs Tuesday could exceed 50f is a
few areas on brisk south winds. For Tuesday night and Wednesday, a
major cyclone deepens over the Great Lakes with New York and PA with
strong southerly winds and strong moisture advection. Probabilities
for showers will increase Tuesday night and Wednesday. Then as the
strong low passes east across northern New England strong cold air
advection will dominate our weather for Wednesday night and
Thanksgiving day. Strong north winds will keep temperatures chilly
for Thanksgiving day with highs in the 30s and low 40s. For Friday
we will keep chances for mainly snow showers or flurries mixing with
rain/sprinkles in our warmer valleys given the uncertainities in
timing W/ this next major system. As it stands now, this storm
doesn't look like it will have any major impact on our forecast area
for the Thanksgiving Holiday and travel as well. Stay tuned as this
Aviation /15z Friday through Tuesday/...
expect a period of MVFR to fuel alternate ceilings this
morning as a batch of rain moves in along a cold front. Will
also likely see MVFR visibility restrictions in this rain/mist
for a time as well. Fuel alternate conditions persist through
16-18z today, before some minor improvement back to MVFR or low
end VFR during the afternoon. Rain showers this morning, will
gradually mix with and change to scattered snow showers by this
afternoon (mainly across cny). These showers could bring brief
visibility restrictions. Conditions should then improve to VFR
for all terminals by this evening (except perhaps lingering bkn
clouds at krme into tonight), as the lake effect showers shift
north and dissipate.
Southerly winds will be shifting this morning and becoming
strong, gusty west-northwest winds into the afternoon hours
15-30 kts. Winds only gradually diminish after sunset this
evening...back below 15 kts. Then eventually shift westerly and
become light overnight.
Saturday...VFR conditions expected.
Saturday night through Sunday...system with snow-rain mix may
pass through the region with associated restrictions.
Monday and Tuesday...mainly VFR.