Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Buffalo New York
125 PM EDT Sat Apr 25 2015
high pressure will remain across the Great Lakes region this
weekend. This will result in some sunshine and warmer...but still
below normal temperatures. A more notable warming trend is expected
by the middle of next week.
Near term /through tonight/...
a narrow ridge of high pressure across the region will remain firmly
in control today. Satellite imagery shows the bulk of the area under
full sunshine this afternoon with a few exceptions. The thicker middle
level clouds which brushed the western southern tier during the middle
and late morning have quickly thinned...allowing for increasing
amounts of sunshine. Recent satellite trends suggest the thicker middle
level clouds upstream will remain over Northern Ohio and northwest
PA through the rest of the afternoon.
An area of stratus over the Saint Lawrence valley and Quebec will
continue to spread southwestward this afternoon...with increasing
clouds from northeast to southwest across portions of Jefferson and
Following a chilly start...temperatures will rebound into the
upper 40s to lower 50s in most areas. The coolest temperatures will
be along the Lake Shores where northerly gradient onshore flow will
push lake cooled air inland a few miles. The gradient wind is light
enough to allow a local lake breeze to develop near downtown Buffalo
this afternoon with winds becoming locally southwest at the end Lake
Erie. The net effect will be to keep all the lakeshores in the lower
40s this afternoon.
High pressure will remain across the region tonight with partly to
mostly clear skies. Lows should be a bit warmer due to slightly
warmer temperatures aloft and some clouds...but radiational cooling
conditions will still be fairly good tonight. Lows will generally be
in the upper 20s to lower 30s.
Short term /Sunday through Monday night/...
on Sunday the upper level low that has persisted over the northeast
this past week will wobble westward as a potent upper level
shortwave rotates around the west side of the low. The shortwave will
retrograde this upper level low westward some Sunday such that
clouds and low level moisture will creep back into the region from
the east. A rain shower is possible Sunday afternoon east of Lake
Ontario...but it will not be until this upper level shortwave drops
across the region Sunday night that light showers (lower elevation
rain...higher elevation rain/limited snow) will become more
On Monday a moist northerly flow will produce light showers/upslope
drizzle across the region. Though northerly this flow will actually
be a warming/isentropic lift flow as a trowel signature will lie
overhead. Shower chances will be greatest across the higher terrain
and the north face of the Tug Hill. As the upper level low and its
associated moisture pull eastward through the day rain showers will
diminish Monday night.
Temperatures will be fairly similar both Sunday and Monday. Sunshine
on Sunday will aid in highs climbing into the low to middle 50s...while
a warming airmass Monday will also send highs into the low to middle
50s. Overnight lows will range both nights from the middle 30s to the
Long term /Tuesday through Friday/...
by Tuesday the long lived upper-level low over New England
will finally make its departure as increasing northwesterly flow
across the northern plain kicks it eastward. This will mark a slow
warming trend back into the low/middle 60s across the forecast area
through mid-week. There is still plenty of model disagreement on the
interaction between a northern stream wave and a cut-off low
drifting across the plains states mid-week. Either way...the colder
airmass is locked further north across Canada and will support
warmer temperatures. Cooler air may make a brief comeback by late
week as the shortwave/cut-off low slide off the East Coast. The GFS
remains the most aggressive with the colder air...while the European model (ecmwf)
keeps the colder air locked to the north. Outside of the shortwave
crossing the forecast area in the Wednesday/Thursday time
frame...the extended should be fairly dry.
Aviation /18z Saturday through Thursday/...
a narrow ridge of high pressure will continue to provide clear skies
for the bulk of the region through this evening. Deeper moisture
rotating around a vertically stacked low stalled over the Canadian
Maritimes will make slow progress into the north country this
afternoon with increasing clouds from northeast to southwest. Ceilings
will remain VFR in the 4-7k foot range with this.
The deeper moisture will overspread the rest of the area from north
to south later tonight and Sunday as the stalled low elongates and
expands back to the west...with a middle level trough developing over
the lower Great Lakes. This will bring increasing clouds to the
region late tonight and Sunday...but ceilings will remain VFR. A few
sprinkles or very light showers may develop Sunday afternoon with
visibility remaining VFR.
Sunday night and Monday...VFR/MVFR with a chance of rain showers.
Tuesday through Thursday...mainly VFR.
a narrow ridge of high pressure will bring lighter winds and waves
today with local lake breezes developing. North winds will develop
Sunday as pesky low pressure over the Canadian Maritimes broadens
its influence again...but winds should remain relatively light.