Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Buffalo New York
139 am EDT Wednesday Jul 1 2015
low pressure will move by just north of the region tonight and
continue to produce a few showers and thunderstorms. A trailing cold
front will cross the area on Wednesday with a few more showers and
thunderstorms. High pressure will finally bring a return to dry
weather by Thursday. This high is forecast to remain in place
through the Fourth of July weekend and provide plenty of sunshine
and warm temperatures for the Holiday.
Near term /through today/...
it will remain mostly cloudy
through the overnight time period with batches of showers rotating
across the eastern Great Lakes region. With the loss of the daytime
heating thunder chances will remain small...with only some
thunderstorms from Ohio possibly reaching SW New York state before daybreak.
Otherwise it will remain mild...with lows in the lower to middle 60s in
most areas with lower 60s dewpoints giving a somewhat muggy feel.
A cold front will cross our forecast area during the course of the
midday and early afternoon Wednesday. This front will generate some
scattered showers and thunderstorms...mainly east of the Niagara
Frontier where diurnal instability should be the greatest. Local
lake breeze boundaries will also develop during the afternoon...
which could also provide a focus for a shower or thunderstorm even
behind the ill-defined synoptic scale cold front.
Short term /tonight through Friday night/...
evening update...the forecast remains on track leading up to a
stretch of fine weather for the Holiday weekend.
Previous discussion...showers will be largely be winding down from
west to east Wednesday night as a cool front slides across the
state. While the bulk of the precipitation should end Wednesday
evening with the passage of the front...the axis of the middle-level
trough will remain upstream and as such cannot rule out a few light
showers as the weak middle-level lift interacts with the limited
moisture left behind the front. Lows will run in the middle to upper
Any lingering low clouds should quickly diminish Thursday morning
however as cooler and drier air advects in from Canada...allowing
for plenty of sunshine on Thursday with temperatures running
slightly cooler than average...in the low 70s. The only catch is
that with the axis of the middle-level trough still making its way
across the forecast area on Thursday...we will see a little more
widespread cloud coverage along with a slight chance of a brief
shower or two across The Finger lakes and southern tier in the
afternoon...but no substantial rainfall is expected.
The middle-level trough will complete its transit of the area Thursday.
With weak upper level ridging and surface high pressure building
across the lower Great Lakes Thursday night...expect a clear and
cool night with radiational cooling allowing readings to drop into
the low to middle 50s. A few of the more sheltered locales in the
southern tier and north country may even dip just below the 50
degree mark. High pressure will remain in control through the rest
of the period though a return to southerly flow as the diffuse high
shifts to the East Coast will allow for a return to more seasonable
temperatures and slightly higher humidity Friday with highs in the
middle to upper 70s and lows Friday night running close to
climatology...within a couple of degrees either side of 60.
Long term /Saturday through Tuesday/...
evening update...have dropped back probability of precipitation on Saturday across the
majority of the forecast area. Dry and warm conditions are expected
for most with a touch of humidity. Have held onto chance probability of precipitation across
the Saint Lawrence River valley and far North County with a front
glancing the North County. Across the southern tier have left slight
chance probability of precipitation near the New York/PA border with some convection across
central PA that may try to sneak up into the southern tier.
It will largely be a quiet Independence day weekend as the region
will remain largely under the influence of high pressure. A large
upper level trough passing to our north may dip close enough to the
region to trigger a few showers across the north country...and some
uncertainty regarding the equatorward displacement of this feature
is enough to warrant keeping in a 20 pop elsewhere...but overall it
should be a largely sunny and mild Fourth of July across western and
north central New York. Skies should remain largely clear and
temperatures will remain similarly mild for the fireworks Saturday
night as upper level ridging over the upper Great Lakes begins to
move into the region.
The fair weather will continue for the latter portion of the weekend
as upper level ridging moves overhead. Temperatures will remain near
average Sunday and Sunday night...however by Monday we should start
to see readings climb back into the 80s as southerly flow returns to
the region. The corresponding increase in humidity and instability
will also bring a chance of showers and thunderstorms back into the
forecast for Monday and more so into Tuesday as guidance currently
indicates another cold front approaching the area.
Aviation /06z Wednesday through Sunday/...
at 06z mainly VFR flight
conditions were found across the region. There continues scattered
showers across the region though thunder has largely ended from the
As temperatures cool some to their dewpoint some IFR/low end MVFR
flight conditions are possible across kjhw/kbuf/kiag later
Later today will feature again mostly cloudy skies varying in the
MVFR/VFR flight range. Showers will continue to form...becoming a
little more widespread towards the afternoon in conjunction with
better daytime instability and the passage of a weak cold front.
This front may even trigger a few thunderstorms along the boundary.
As this front clears the region late this afternoon and
evening...drier air behind the front will end shower chances and
allow for a decrease in clouds. However some IFR low stratus is
possible to hang over the southern tier...including the kjhw
A southwest wind 5 to 10 knots will increase towards 15 knots NE of
Lake Erie behind a Lake Erie breeze. Winds will veer to westerly and
rapidly decrease this evening.
Thursday through Sunday...VFR.
low pressure will pass across southern Ontario province tonight with
an associated cold front crossing the lower lakes on Wednesday.
Southwest winds will freshen a bit along and behind the cold front
on Wednesday with Small Craft Advisory conditions developing on Lake
Otherwise prevailing conditions should remain below advisory levels
Thursday as high pressure builds into the lower lakes. High pressure
will then remain in control for the upcoming Holiday weekend with
early indications of light winds and flat wave action.
Marine...Small Craft Advisory from 8 am this morning to 8 PM EDT this
evening for lez020-040-041.