Scientific Forecaster Discussion

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Area forecast discussion 
National Weather Service Buffalo New York
145 am EDT sun Apr 20 2014

Synopsis...
an area of high pressure will bring fair and seasonably warm weather
to the region today and Monday. A cold front will pass across the
eastern Great Lakes region Tuesday and bring showers along with
cooler temperatures.

&&

Near term /through tonight/...
a broad area of high pressure over New England and expanding across
the Great Lakes and Ohio Valley region will continue to bring
pleasant conditions to the region today. Temperatures aloft at 850
hpa warm to around +4 to +8c east to west and this will bring
widespread 60s to the region. Warmest areas will likely be across
western New York.

The far eastern extent of a warm front ahead of a Midwest storm
system will lift across the region later this afternoon and
tonight. This boundary will bring some middle and high level cloudiness
across the region. Thickest clouds will be found northward. We
will remain dry with overnight lows in the low to middle 40s. A few
upper 30s will be found near the state line under mainly clear
skies.

&&

Short term /Monday through Tuesday night/...
high pressure extending back across the Middle Atlantic States from
Nova Scotia will keep fair dry weather over our region Monday...with
Monday slated to be one of the nicer days within this forecast
package. While there will be some cirrus around...any cloud cover
of note will be confined to sites north of Lake Ontario where a
stalled frontal boundary will be in place. Our partly to mostly
sunny skies will thus combine with 850 mb temperatures in the vicinity of 8c to
support afternoon highs that will range from 70 to 75 across the
western counties to the middle 60s east of Lake Ontario. As is usually
the case at this time of year...it will be relatively cool within
a couple miles of the Lake Shores where lake breeze circulations
will hold maximum temperatures in the upper 50s to lower 60s.

Our stretch of fine weather will deteriorate Monday night as a pair
of shortwaves digging across the upper Great Lakes will deepen a
corresponding surface low that will track by to our north...from
Georgian Bay to the Ottawa Valley. Moisture will pool ahead of the
associated cold front...which will be over the far western counties
around daybreak Tuesday. Some showers will be possible over the far
western counties and Thousand Islands region as a result...although
the bulk of our forecast area should be precipitation free during the
nighttime hours.

As the front crosses our region Tuesday morning...a 100kt h25 jet
over Quebec will induce a relatively narrow swath of upper level
lift to accompany the low level convergence of the frontal boundary.
This will result in a few hours of showers...with high likely probability of precipitation
being maintained from continuity. The western counties will experience
the bulk of their showers during the morning with most of showers
east of Lake Ontario being focused on the midday and early afternoon.
Middle level lapse rates under 6 degree/km will work against any
convection. Temperatures on Tuesday will average 10 degree f below
those from Monday...with highs generally within a few degrees of 60.

Residual troughing and the possibility of a secondary cold frontal
passage over the lower Great Lakes Tuesday night and early Wednesday
will prolong the chance for some leftover showers...especially east
of Lake Ontario where a little deeper moisture field will be present.
While cold advection will be underway...temperatures aloft should stay just
mild enough to keep any nuisance precipitation in liquid form.

&&

Long term /Wednesday through Saturday/...
a progressive...somewhat amplified pattern will translate into
changeable weather during this period. While it will be seasonably
cool on Wednesday...ridging over the nations middle section will push
east and boost our Mercury back above normal into next weekend. Some
details...

High pressure over the upper Great Lakes will drift east during the
day Wednesday...with subsequent middle level drying and subsidence
leading to clearing skies. It will be breezy and quite cool though as
850 mb temperatures of -5c will hold our afternoon maximum temperatures in the 40s and
lower 50s f. Normal high temperatures for this point in the season
are generally in the upper 50s.

The surface high will ease across the lower Great Lakes Wednesday night
and Thursday. This will support excellent conditions for Star gazing
Wednesday night...with ample sunshine and moderating 850 mb temperatures
leading to pleasant warming for Thursday. Afternoon readings will
climb back to near normal levels at this time.

As the surface high moves east of our region Thursday night...the door
will be open for a Pacific based cool front to cross the lower
lakes. Some showers will become possible over the far western
counties late Thursday night...with a more widespread opportunity
for showers on Friday as the front and its supporting middle level
shortwave pass through the region.

The passage of another cold front will push across the lower Great
Lakes on Saturday...prolonging the potential for scattered shower
activity.

&&

Aviation /06z Sunday through Thursday/...
VFR flight conditions at 06z are expected to persist through the taf
period with a general light wind.

Outlook...
Monday...VFR.
Tuesday...mainly VFR with periods of MVFR in rain showers activity.
Wednesday and Thursday...VFR.

&&

Marine...
surface high pressure over New England New England today through
Monday will bring minimal waves on the lakes and just a gentle
breeze across bodies of water.

&&

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

&&

$$

Synopsis...Thomas
near term...Thomas
short term...rsh
long term...rsh
aviation...Thomas
marine...Thomas