Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Buffalo New York
1052 am EDT Thursday Oct 30 2014
cool air flowing into the region this morning will promote continued
areas of cloudiness inland from the lakes through the day. A low
pressure system is expected to cross the area Friday and
Saturday...ushering in chilly temperatures for the weekend along
with some rain showers Friday and Saturday. Most of the
precipitation is now expected to remain liquid...although a few wet
snowflakes may mix in on the hills Saturday night. A warming trend
is then expected early next week.
Near term /through tonight/...
water vapor imagery this morning displays two shortwaves. The first
one is lifting northeastward from our region towards northern New
York and New England. A second...and more potent is dropping
southward across northern Manitoba.
A fair amount of clouds will remain across our region today. Low
level moisture seen on infrared imagery combined with a northwest flow
behind a departing shortwave will leave plenty of clouds today for
our region. There will be some clearing over the lakeshores...and
the northern Niagara Frontier today.
Under these clouds highs today will struggle to reach 50 with most
areas in the middle to upper 40s through the day.
Over the course of the day today the second shortwave over
Manitoba will deepen a surface low over the western Great Lakes. A
warm front extending eastward from this surface low will provide a
boundary for which southerly...and increasing moisture flow will
produce a few rain showers across far western New York towards
daybreak Friday morning. Areas from the Genesee Valley eastward
should remain dry through the daytime hours.
Though this area of low pressure will be deepening at the
surface...it will not be to deep...with a central surface pressure
remaining above 1000mb. This will not be deep enough to create any
gusty winds...rather just a light westerly wind that will back to
southerly through the night. With this light wind temperatures
tonight will fall back into the low to middle 30s across the north
country and inland southern tier...while remaining around 40 near
the immediate lake shoreline.
Short term /Friday through Saturday night/...
there remains little question that much colder air will build into
the region by this weekend...but the prospects for snow continue to
diminish. 00z model consensus remains in good agreement that a
potent upper level shortwave will drop across the Great Lakes region
on Friday then eventually evolve into a closed upper low near the
Carolinas on Saturday. This will eventually translate into strong
surface low pressure off the Atlantic coast on Saturday night.
There will be an increasing chance for showers from west to east on
Friday with the approach of the shortwave. However the unusual north
to south track will keep our region on the warm side of the system.
Ensemble 850mb temperature guidance is closely clustered from -1
to -2c which should be too warm to support snow with slightly warmer
temperatures in the boundary layer. Rainfall amounts should be on
the light side with weak lift out ahead of the shortwave.
Temperatures will still be on the cool side...with highs ranging
from the middle 40s to lower 50s.
The developing system will result in a complex surface map this
weekend however for our region the bottom line will be quite simple
with a strengthening NE flow and a broad upper level trough aloft.
Showers will continue...but the cause the precipitation will
transition from the weakening upper level system to lift generated
by upslope and lake enhancement. Consensus quantitative precipitation forecast continues to be light
and temperatures aloft will largely remain too warm to support snow
on Friday night. By Saturday...the upper level trough axis will move
to our east which will filter in cooler air into the region. This
will allow some snowflakes to mix in on Saturday...especially across
higher terrain away from the lakes. However...precipitation should
continue to be on the light side as drier air builds into the
boundary layer. This may be offset somewhat by lake enhancement from
cooler air aloft...but eventually the dry air should win out with
precipitation ending late Saturday night.
The best chance for accumulating snow will be on Saturday
night...from a combination of lake enhancement and upsloping.
However...any amounts should be light and although 850mb
temperatures will finally be cold enough to support snow...NAM
BUFKIT shows dry air above -10c which suggests a limited dendritic
snow growth zone. Moisture may only be enough for lake enhanced
As advertised...temperatures will be much cooler Saturday with highs
only in the lower 40s. Then cold air advection will drop lows into
the lower 30s near the lakeshores with upper 20s inland on Saturday
Long term /Sunday through Wednesday/...
while the New England coast may still be dealing with the effects of
a deep coastal low Sunday...western and north-central New York will
be entering a period of benign weather as a steep ridge over the
central United States translates across the Great Lakes. Cool
northwesterly flow on the front side of the ridge will keep
conditions cool and cloudy on Sunday as lake effect cloudiness will
linger across the region. However as we move into Monday...the
region should see a significant moderation in temperatures as the
upper level ridge moves overhead and the surface high slides to the
East Coast...opening up the lower Great Lakes to warm southerly
return flow. Alas the mild weather will come at a price as warm
advection aloft will generate a decent amount of middle/high
clouds...particularly across western New York.
The progressive pattern will continue as we move deeper into next
week as the upper level ridge moves to the East Coast and the next
low pressure system takes aim at the Great Lakes. Models are
currently in very good agreement regarding the upper level trough as
it lifts across the northern rockies across the upper Midwest Sunday
night through Monday night. A sharp surface frontal boundary will
develop as low level thermal gradients tighten across the
nation's middle-section as warm and moist southerly return flow across
the eastern U.S. Encounters milder Pacific air advecting southeast
out of the northern plains over the top of high pressure in the
Great Basin. Tuesday could end up being a very mild day across the
lower Great Lakes...with temperatures climbing into the upper 50s to
around 60s. 00z guidance continues to bring a cold frontal boundary
across the region with a consensus timing of Tuesday night. This
will usher in slightly cooler air for Wednesday and bring a chance of
showers with its passage.
Aviation /15z Thursday through Monday/...
at 15z largely low end VFR ceilings...and some embedded MVFR
ceilings...mainly in the higher terrain...are found across the region
within a weak northwest flow. Expect the low level moisture to
continue with a fair amount of clouds through the day today with
this northwest upslope flow.
Through the day today an area of high pressure will build
northeastward from the lower Ohio Valley. Clouds will slowly lift
through the daytime...thus VFR conditions should prevail at most taf
Tonight a warm front will lift across the central Great Lakes. This
will bring another increase in clouds overnight...though again
largely MVFR/VFR. Some light rain showers will reach far western New
York around 9-15z tomorrow morning.
Friday...VFR deteriorating to MVFR/IFR with rain showers becoming
Saturday...areas of MVFR with scattered to numerous rain showers
possibly mixed with wet snow on the highest hills.
Sunday and Monday...mainly VFR.
a relaxing pressure gradient has allowed for winds and waves on Lake
Erie and Lake Ontario to fall this morning. Latest observations on
Lake Ontario suggest wave heights have fallen below 3 feet...and
winds have continued to trend downward. Given these latest
observations have decided to cancel the remaining small craft
advisories on Lake Ontario...thus no more advisories remain at this
time. Winds will continue to subside through the day...becoming
light and variable overnight across both Lake Erie and Lake Ontario.