Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Buffalo New York
343 PM EDT sun Oct 4 2015
high pressure over Quebec will continue to build slowly south into
the Great Lakes and northeast tonight through the middle of the
coming week. This will maintain dry weather with temperatures
warming to slightly above average. The next chance of rain will
not arrive until Thursday night or Friday when low pressure is
forecast to move through the Great Lakes.
Near term /through Monday/...
high pressure over Quebec will remain over western and central New
York ensuring dry weather through the period. An extensive shield
of middle and high level cloud cover is located just upstream across
the central and western Great Lakes...with the eastern edge
hugging western New York. This area will likely budge little
overnight resulting in a difficult overnight temperature forecast.
Areas underneath the cloud cover remaining in the lower to middle
40s...but areas which see clear skies the longest likely seeing
temperatures drop into the middle to upper 30s with some patchy frost
possible. Will hold off on any frost advisories at this point
given uncertainty revolving around the cloud cover.
Middle and high level clouds likely to spill over the region Monday
as upper flow flattens a bit. Filtered sunshine should help
temperatures top out in the upper 50s to lower 60s.
Short term /Monday night through Wednesday night/...
during Monday night and Tuesday western and north central New York
will remain under the influence of broad surface high pressure
draped across the Great Lakes and northeast...which will result in
continued fair and dry weather for our region. While leftover
moisture from the former coastal frontal zone will still result in a
decent amount of cloud cover lingering across our region Monday
night...this should tend to thin out and/or get advected further
eastward on Tuesday...which should allow the return of some partial
The axis of the surface ridge will then slip to our south Tuesday
night and Wednesday...while a modest middle level trough slides across
northern Ontario and Quebec and pivots its trailing weak cold front
across New York state. At this point it still appears as if the
boundary will be too starved for both moisture and upper support to
produce much more than some clouds as it passes through...with high
pressure then rebuilding across the area in its wake Wednesday night
while providing the area with additional fair/dry weather.
With respect to temperatures...these will average a little above
early October normals through the day on Wednesday...before slipping
back to right around average Wednesday night as a slightly cooler
airmass builds into the area behind the cold front. More
specifically...expect daytime highs to mostly be in the middle 60s both
Tuesday and Wednesday...while nighttime lows mostly in the 40s
Monday night warm into the upper 40s/lower 50s out ahead of the
approaching front Tuesday night...then fall back into the lower to
middle 40s in its wake Wednesday night.
Long term /Thursday through Sunday/...
on Thursday...high pressure directly overhead at the start of the day
will slowly drift east and off the Atlantic coastline by evening...
while a Pacific-based middle level trough and associated surface wave
presses from the upper Mississippi Valley into the central Great
Lakes. While this latter system will bring some increase in middle
and high cloud cover to our region through the course of the day...
it will remain far enough to the west to allow our region to enjoy
another day of dry weather. With some modest warming of our airmass
developing out ahead of this system...daytime highs should range
through the lower half of the 60s.
After this...the new 12z GFS and European model (ecmwf) are in considerably better
agreement that the aforementioned surface low will push across our
region on Friday while bringing the next general opportunity for
some rainfall...before passing off to our east by the start of next
Saturday. Based on this scenario and wpc support for this idea...have
indicated continued mild temperatures and the highest overall probability of precipitation /likelies/
for the last day of the work week...followed by a return to drier and
somewhat cooler conditions for Saturday as high pressure and cooler/
drier air builds across our region.
As we approach the end of the period...the medium range guidance is
in general agreement on upper level troughing briefly sharpening
up over eastern Canada...while pushing a secondary and somewhat
moisture-starved cold front into the area next Sunday. This could
bring a few additional showers to our region to close out the period...
while temperatures remain right around seasonal averages.
Aviation /20z Sunday through Friday/...
expect VFR conditions to prevail this afternoon through tonight.
Middle level cloud cover across the central Great Lakes and upper
Midwest will slowly advance toward the area through tonight. If
the cloud cover holds off long enough some possible IFR fog will
be possible at kjhw between 08z and 13z.
Monday through Thursday...VFR.
Friday...VFR/MVFR with showers likely.
strong high pressure over Quebec will continue to produce moderate
easterlies on Lake Ontario with Small Craft Advisory conditions on
the west half of the lake lasting through this evening.
High pressure will weaken and build south through the early part
of the work week with the pressure gradient relaxing and winds
Marine...Small Craft Advisory until 11 PM EDT this evening for loz042-