Scientific Forecaster Discussion

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Area forecast discussion 
National Weather Service Buffalo New York
726 am EDT Sat Apr 19 2014

Synopsis...
high pressure will bring fair and dry weather this weekend with
warming temperatures on Sunday. The next chance for precipitation
come late Monday night into Tuesday as a cold front move through the
lower Great Lakes.

&&

Near term /through tonight/...
a strengthening ridge will move east and settle across the
eastern Great Lakes today and tonight providing fair and dry
weather. 850 mb thermal trough propagating across the area today
will keep temperatures just a smidgen below normal...with most
highs in the lower to middle 50s.

Good radiational cooling night tonight under clear skies and a light
wind regime. Most overnight lows within a few degrees of freezing.

&&

Short term /Sunday through Tuesday/...
this period will open with a beautiful Easter Sunday...as surface
high pressure over eastern New York and western New England slowly
drifts eastward and off the New England coastline. Plenty of dry air
and subsidence associated with the high will result in continued dry
weather...with just a modest increase in high cloudiness expected in
advance of a weak cold front sliding southward across southern
Ontario. At the same time...a developing return flow around the
departing high will help pump 850 mb temperatures up to between +3c and
+7c...which will translate into highs in the upper 50s to lower 60s
across the north country...and in the middle to upper 60s across the
bulk of the area south of Lake Ontario. The one exception to all
this will be along the immediate lakeshores...where developing lake
breeze circulations will help keep temperatures much cooler...and
potentially confined to the lower to middle 50s in some locations.

Sunday night...the aforementioned frontal boundary will sag a little
further south into the Saint Lawrence valley where it will then
stall through the first part of Monday...before lifting a little
further north again Monday afternoon in response to a digging middle
level shortwave along the central US-Canada border...and the
consequent development of a broad surface wave over the central
Great Lakes. At this point...it appears that any shower chances
associated with the front will remain confined to the Saint Lawrence
River and points northward through Monday...with our area otherwise
remaining dry along with just a modest increase in cloud cover.
Across the north country...this should be enough to render skies
mostly cloudy for at least a part of Sunday night and Monday...while
areas south of Lake Ontario should remain partly cloudy/partly
sunny. With a milder overall airmass in place...lows Sunday night
should average some 10 degrees warmer compared to Saturday night...
with most areas seeing readings bottom out in the lower to middle 40s.
These will be followed by an even warmer day on Monday compared to
Sunday...when 850 mb temperatures of +6c to +9c should support widespread
highs in the middle 60s to lower 70s. The exception to this will be
across those Lakeshore areas immediately northeast of the lakes...
where a general west-southwesterly flow will keep readings
noticeably cooler.

Monday night and Tuesday...the upstream surface low will slide east
into southern Ontario by Tuesday morning...before heading off to
eastern New York/western New England during the afternoon. In the
process...it will push its trailing cold front across the area
between very late Monday night and Tuesday...which should be
accompanied by a decent band of showers given the presence of
sufficient moisture and lift along the front. Have thus continued
with a swath of high likely probability of precipitation for this time frame...which peak
Tuesday morning before slowly tapering off Tuesday afternoon as the
front slides off to the east. Temperature-wise...expect mild lows in
the middle 40s to lower 50s Monday night given the deep southwesterly
flow of mild air that will remain in place ahead of the encroaching
cold front...with highs in the upper 50s to lower 60s then following
for Tuesday.

&&

Long term /Tuesday night through Friday/...
early in this period...lingering scattered showers will gradually
diminish from west to east Tuesday night and Wednesday as the
responsible surface low bodily lifts northeastward into the Canadian
Maritimes...and high pressure and drier air builds eastward from the
upper Great Lakes. The incoming airmass will also be noticeably
cooler...enough so to send high temperatures back down to below normal
levels in the middle and upper 40s on Wednesday...with slightly colder
than normal readings then continuing through Wednesday night.

After that...the aforementioned surface ridge will crest directly
overhead on Thursday...before sliding eastward and eventually giving
way to the next surface low Thursday night and Friday. This will
result in dry weather for both Thursday and Thursday night...before
shower chances return on Friday. As for temperatures...a general warm air
advection pattern setting up across the area should allow temperatures to
recover back to near-normal levels in the middle and upper 50s on
Thursday...before climbing well into the 60s again to close out the
work week.

&&

Aviation /12z Saturday through Wednesday/...
residual lingering cloudiness in the wake of a cold frontal passage
will continue to produce MVFR ceilings at kart through the morning.
Little impact on aviation operations is expected elsewhere. Clouds
will scattered out at kart by around 16z...as drier air continues
to advect into the region...as high pressure builds overhead
today. VFR/unlimited ceilings are expected areawide this afternoon
through tonight.

Outlook...
Sunday through Monday...VFR.
Tuesday...VFR/MVFR with showers.
Wednesday...VFR/chance showers east.

&&

Marine...
surface high pressure over the upper lakes will build into the lower
lakes and northeast through the weekend. Expect light winds and
minimal waves through this period.

&&

Buf watches/warnings/advisories...
New York...none.
Marine...none.

&&

$$

Synopsis...tma
near term...tma
short term...jjr
long term...jjr
aviation...tma
marine...tma