Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Buffalo New York
752 PM EDT sun Mar 9 2014
a weak storm system will drop across Eastern Lake Ontario and bring
some light snowfall across the North County. Slightly warmer
temperatures will move in on Monday and Tuesday then another storm
system has the potential to bring some snow mid-week...followed by
another shot of cold air.
Near term /through Monday/...
high pressure is now ridged from the Ohio Valley northeastward
towards New England this evening. This is providing for quiet
surface conditions...though middle and high level clouds are building
aloft ahead of the next system of note.
An area of warm air advection in the middle-levels will dive across
eastern Ontario Provence and into the north country tonight. Given
the large scale lift and isentropic upglide...have high confidence in light
snow across Jefferson/Lewis counties...extending into northern
Oswego County. Using a NAM/sref/rgem/GFS blend for quantitative precipitation forecast...expect 1 to
3 inches in these areas tonight. South of this...have much lower
confidence...with a minority of model guidance (00z NAM/12z rgem and
some mesoscale guidance) forecasting qpfs up to a quarter inch
across far western New York. The main source of lift appears to be
low level convergence east of Lake Erie...possibly due to westerly
925mb winds which convergence against the Chautauqua ridge. Whatever
the case...with temperatures too warm for any lake
contribution...such high qpfs seem questionable given poor model
agreement and is likely dependent on how much moisture advects from
the upper lakes. This will likely bring some light snow or rain
showers late tonight and into Monday...but feel the higher quantitative precipitation forecast
models are overdone. With cloud cover in place...and warm air
advection aloft...expect temperatures to drop very little tonight.
Lows should average in the middle 20s. Also expect a persistent breeze
across the Niagara Frontier and along the Lake Erie shoreline...with
gusts to 35 miles per hour overnight.
On Monday...the temperature gradient aloft will sharpen as a well
aligned wind field aloft helps enhance a warm frontal boundary
across our region. There will not be any well defined areas of warm
air advection...but any ripple could spark a rain or snow shower
along the boundary. This sharpening boundary aloft will trap
moisture in the low layers...likely resulting in lingering clouds
for most of the day. Meanwhile...a southwesterly flow will bring in
warmer and fairly moist air...with a possibility of fog as dew
points rise into the middle 30s. Eventually...the low moisture should
start to mix out across western portions of the southern tier late
in the day...while clouds should persist elsewhere. Temperatures
should rise into the upper 30s to lower 40s...with forecast highs on
the lower side of available guidance due to the lingering cloud
cover. If low level moisture does mix out early...that would allow
temperatures to rise significantly more than forecast...but given
the light flow and fairly deep moisture expect that is a less likely
Short term /Monday night through Wednesday night/...
as low pressure over central Quebec starts a weakening and filling
process...a slow moving cold front trailing this low will slow
further and stall across the Lake Ontario basin and southern
Ontario. This will form a col in the pressure pattern between high
pressure centers over western Ontario and the waters of the western
Atlantic...and regions of low pressure over Quebec and a stronger
developing system in the middle Mississippi Valley. Partial sunshine
through middle and high clouds and a neutral thermal advection pattern
will allow somewhat milder temperatures in the upper 30s to lower 40s for
most of the forecast area...even to the middle 40s closer to The Finger
The benign weather will not last long as the midwestern storm will
gather strength and move up the Ohio Valley Tuesday night and
Wednesday. A warm front will become established along or just south
of the New York/PA line with surface winds across New York state veering
to northwest then north as the region of low pressure passes
eastward across southern Pennsylvania. Expect a widespread steady
snow to develop late Tuesday night and intensify during Wednesday...
diminishing Wednesday evening as the backside of the middle/upper
deformation zone passes. A general consensus of GFS/ECMWF/gefs shows
western to central New York receiving the greatest amount of snow...but
whether that amount of snow will reach warning criteria is still in
question. Also...given the recent model variability of storm tracks
and placement of the heavier snow swath...will hold off a little
longer on a Winter Storm Watch until confidence is higher.
Gusty northerly winds will bring cold enough airmass to kick off
some lake snow showers overnight Wednesday night. Overnight lows
will plummet to the lower single numbers to below zero readings...
with temperatures closer to 10 above right along the Lake Ontario shore.
Long term /Thursday through Sunday/...
colder air will follow the storm with northerly winds across Lake
Ontario producing a broad area of lake effect snow showers on
Thursday. European model (ecmwf) and GFS show a rather narrow through with 850mb
temperatures falling to -20c but subsidence inversion and dry air down to
about 4kft will limit the vertical development of snow cells. Expect
scattered lake snow showers with some heavier but fast moving cells.
High temperatures on Thursday will struggle to get out of the teens for
most locations with lower 20s along the immediate Lakeshore areas
close to Lake Ontario.
The cold will be short lived as the trough remains progressive and
quickly moves out of the area. Expect temperatures to recover to
near average again by Friday. The next chance of light snow will
arrive later Friday night and Saturday as a weaker middle level trough
digs into the Great Lakes and northeast. Highs on Friday and
Saturday will be in the middle to upper 30s.
High pressure ridging in across the Great Lakes will bring an end to
any chance of precipitation and should offer a fair amount of sunshine.
This will offset the cold advection and keep highs in the middle to
Aviation /00z Monday through Friday/...
at 00z mainly VFR flight conditions were found across the
region...though lower MVFR ceilings were nearing the Saint Lawrence
valley. For tonight expect ceilings to continue to lower as warm air
advection aloft continues ahead of a weak 850 hpa shortwave. These
features will bring a period of light snow to the Eastern Lake
Ontario region overnight...lowering visibilities down to IFR within snow
overnight for the kart airfield. As this shortwave advances eastward
later tonight expect the snow to settle southward some...though
likely not as intense and concentrated with scattered light showers
of snow later tonight and into the morning horus tomorrow south of
Lake Ontario. Ceilings will lower...especially downwind of Lake Erie
tomorrow where a southwest wind of rising dewpoints over the Frozen
Lake may bring low clouds of IFR across kbuf and kiag.
Winds aloft will pick up this evening ahead of the fast moving
shortwave and this will result in low level wind shear where these higher winds
struggle to mix to the surface. Likely areas for this low level wind shear will be
kjhw...though possibly also at kroc and kart.
Widespread MVFR flight conditions and near Lake Erie IFR will
continue as moisture lingers beneath a low level inversion. Some
improvement is possible late in the taf cycle.
Monday night...MVFR. In ceilings and patchy fog.
Tuesday night and Wednesday...IFR. Snow.
Thursday...VFR/MVFR. A chance of snow showers.
a weak ridge of high pressure will build across the lower lakes
through today before a warm front shift across the area tonight.
Southwest winds will increase this evening. Based on this...have
issued an Small Craft Advisory for Western Lake Ontario where winds will be
strongest...with no other headlines since winds will be weaker on
eastern portions of Lake Ontario. After this...expect a modest
southwesterly flow Monday through mid-week. A developing storm may
bring Small Craft Advisory to possibly gales on Wednesday...depending
on its strength and track.
Marine...Small Craft Advisory until 5 am EDT Monday for loz042.