Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Buffalo New York
1016 am EDT sun Mar 16 2014
flurries and snow showers southeast of Lake Ontario this morning
will taper off and give way to increasing amounts of sunshine today
as high pressure builds into the Great Lakes. Temperatures will run
well below average today...before a moderating trend develops this
week. Expect dry days Monday and Tuesday with sunshine through the
day before a chance of light rain arrives by Wednesday.
Near term /through tonight/...
radar imagery this morning showing scattered flurries and light snow
showers pushing into the southern tier and Finger Lakes due to a
combination of upslope flow and lake moisture off Lake Ontario.
Visible satellite imagery also suggests a weak band of light snow
across portions of Wayne and northern Cayuga County extending into
western Oswego County. All of this will remain light...with a spotty
dusting to half inch accumulation through midday. This afternoon
ongoing drying and mixing from the strong March sun angle will help
to mix out any remaining snow showers. Extensive stratocumulus
southeast of Lake Ontario and across the higher terrain of The
Finger lakes and southern tier will hold on through early afternoon
before increasing amounts of sunshine later today.
Upper level troughing sliding eastward into Quebec today...with
subsidence developing overhead as surface high pressure and
increasingly drier air noses in from the upper Midwest/western Great
Lakes. Cold advection continues with 850 mb temperatures dropping to
near -20c...about two Standard deviations below normal. With the
very cold temperatures aloft...despite the increasing sunshine it
will be a cold day with highs only in the middle to upper teens in most
areas...some 20 to 25 degrees below normal. Winds will ease a bit
but still should have wind chill values in the single numbers.
The clear skies will continue tonight as high pressure continues to
settle eastward. Overnight lows in the single numbers with readings
as cold as 10 below east of Lake Ontario.
Short term /Monday through Wednesday night/...
Arctic high pressure will build east across the Great Lakes to the
St Lawrence Valley for the first half of next week providing
plentiful sunshine and dry weather. The high will also keep our
area shielded from a southern stream storm which will shift across
the deep south and off the Carolina coast. The location of the
center of high pressure as it shifts east with respect to New York
will be the main player in our temperature forecast.
The center of the high will shift east on Monday from northern
Michigan to just north of Lake Ontario. Northerly winds across New
York state which will become light and variable through Monday. The
reinforcing cold advection will keep well below average temperatures
with highs Monday only climbing into the 20s to just near 30 along
the western southern tier New York/PA line. Monday night and Tuesday the
high shifts northeast of the forecast area centering across southern
Quebec/northern New England. Winds across New York will become
southeasterly ahead of a clipper crossing the upper Midwest. This
will advect warmer air northward gradually warming temperatures back
to near middle March averages. Another cold night possible Monday under
mainly clear skies with lows ranging widely from the single numbers
east of Lake Ontario to the upper teens over the western southern
tier. On Tuesday we look to warm to the lower 40s across western New
York and middle 30s for central New York. A breezy southeasterly flow
Tuesday night will keep temperatures overnight generally near 20 east of
Lake Ontario and to the upper 20s to lower 30s elsewhere.
Low pressure will move northeastward from the Central Plains to the
upper Midwest from Tuesday to Wednesday and the preceding warm front
will cross the region on Wednesday morning. Precipitation along the front
will start as light snow in the cold air...then transition to a day
of rain showers likely...then back to a mix of rain and snow showers
during Wednesday night as the trailing cold front crosses the
region. The airmass following the cold front is of Pacific origin
and will be thermally modified...thus overnight lows Wednesday night
will be in the upper 20s to lower 30s.
Long term /Thursday through Saturday/...
a Pacific sourced flow and low amplitude middle-level ridging will help
the last day of what has been an exceptional winter season feel more
like Spring as we transition into this new season this week. Forecast
models are consistent with lifting a clipper north across the upper
Great Lakes to Quebec Wednesday and Thursday. Deep layered south to
southwest flow ahead of this clipper will boost temperatures to the
middle and upper 40s Wednesday across western New York and around 40
east of Lake Ontario. Some downsloping across the Lake Shores and
southern tier/Genesee valleys may even bring temperatures topping 50
degrees. Models show a cold front and low level jet crossing New
York during the day will bring a period of rain showers but exact
timing still needs to be ironed out in future runs.
On Thursday we will welcome Spring with open arms at 1257pm. Behind
the cold front and clipper a modified Pacific sourced airmass will
remain across the forecast area as broad high pressure over the
central states shifts east. Some lingering moisture and cooler air
aloft may bring some diurnal instability rain/snow showers on
Thursday. Temperatures look to run near average with highs around 40 and
lows in the upper 20s. The surface high will shift across the
southern half of the East Coast by Friday with drier air and
subsidence likely preventing much of any precipitation with near average
temperatures. There are signs of another clipper to arrive Friday
night or Saturday with separate model solutions for its track...so
have featured a chance of rain showers until better agreement in
models is found.
Aviation /14z Sunday through Thursday/...
areas of MVFR ceilings will persist southeast of Lake Ontario and also
across the higher terrain of The Finger lakes and southern tier
through early afternoon before improving to VFR and scattering out
later today. Across the lower elevations of western New York including
kbuf and kiag and also the north country this process has already
occurred with mainly VFR conditions.
High pressure and dry air will bring clear skies and VFR tonight.
Monday and Tuesday...VFR.
Wednesday...VFR/MVFR with a chance of rain showers.
Thursday...VFR/MVFR with a chance of rain/snow showers.
a moderate northwest flow will continue across the lower Great Lakes
today maintaining Small Craft Advisory conditions on Lake Ontario.
Winds will diminishing tonight as high pressure builds into the
Great Lakes region. Fairly light winds are expected across all
marine areas Monday as high pressure remains in control.
Marine...Small Craft Advisory until 5 PM EDT this afternoon for loz042-