Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Cleveland Ohio
916 am EDT Monday Jul 28 2014
an upper level trough will persist over the central Great Lakes
through the week. This as high pressure attempts to move up the
Ohio River valley Thursday into Friday.
Near term /until 6 PM this evening/...
increased probability of precipitation inland northestern Ohio for the remainder of the morning.
Otherwise no big changes.
The second of a series of troughs is currently moving across the
eastern portion of the County Warning Area. Rainfall is briefly
heavy...mainly closer to the Lakeshore. We will then await the
next trough that is pivoting across Michigan. This trough will
cross the region through early afternoon. We thought about
shortening up the time for the Flash Flood Watch but at this point
will wait to get the trough axis past the region before any
changes are made. The Flood Watch area will have the best chance
of seeing some heavier rainfall amounts...especially if a warm
rain process can develop in a band off of the lake.
Otherwise it will be much cooler today with the showers and cloud
cover. Highs will generally be within a couple degrees of 70.
However a few locations in northwest PA may stay in the middle 60s.
Short term /6 PM this evening through Thursday night/...
the upper level trough will remain the main forecast nuisance
through Thursday. A couple more pieces of energy will rotate
through the trough with one arriving Tuesday afternoon and another
on Wednesday afternoon/evening. These two time period will be the
enhanced periods for showers. Unfortunately with the cool air
aloft a shower could develop over the eastern half of the region
downwind of the lake at any point tonight through Thursday night.
It will be cool through the short term with highs generally 5 to
10 degrees below seasonal averages. This puts highs in a range
from the upper 60s to middle 70s.
Long term /Friday through Sunday/...
just as the Great Lakes upper level low departs to the northeast on
Friday...the next piece of energy will drop into the trough across
the upper Midwest. The trough will cause scattered showers and
possibly thunderstorms over the weekend as it slowly moves east
overhead. The airmass will not be as cool as associated with the
trough during the first part of the week...but temperatures will
remain at or below normal through the extended. Made few changes to
the going forecast which already included a chance of showers each
Aviation /12z Monday through Friday/...
low pressure is over New York this morning with a trough extending
westward across Lake Erie. Scattered showers will continue across NE
Ohio/northwest PA this morning as the trough swings through. Thunderstorms
have mostly shifted east of Erie but can not rule out a chance of a
thunderstorm at the terminal. Otherwise ceilings range from IFR in
NE Ohio to MVFR in Northwest Ohio. IFR expected to lift through 15z with
ceilings continuing to slowly lift to VFR/MVFR through the
afternoon. Northwest Ohio will likely scatter out tonight while clouds may
linger in NE Ohio/northwest PA...especially closer to the lake. Winds will
shift to the northwest and become breezy with the passage of the
trough with many locations gusting to 20+ knots.
Outlook...occasional non VFR in showers Tuesday through Friday.
a trough over Lake Erie this morning will pivot south pulling a cold
front over the lake with winds shifting around to north and
northwest at 15 to 25 knots behind it. The brisk onshore flow will
result in Small Craft Advisory conditions for the whole South Shore
of Lake Erie. A Small Craft Advisory is in effect until 4 PM for
areas west of the islands and through tonight for the central and
eastern portion of the lake. There will also be a risk of rip
currents for all areas...especially east of the islands where waves
building to 5 to 7 feet will yield a high risk or rip currents. With
the low located east of the lake this morning...there also appears
to be sufficient shear for a chance of waterspouts...mainly through
15z. Winds will decrease to below 15 knots overnight.
At this time not expecting a Small Craft Advisory to be needed for
later Tuesday as winds back to SW and increase ahead of the next low
pressure system approaching from the north. This low will linger
over the central Great Lakes through middle-week with scattered showers
and a chance of waterspouts during the middle-week time frame.
Ohio...Flash Flood Watch until 4 PM EDT this afternoon for ohz011>014-
PA...Flash Flood Watch until 4 PM EDT this afternoon for paz001>003.
Marine...Small Craft Advisory until 4 am EDT Tuesday for lez144>149.
Small Craft Advisory until 4 PM EDT this afternoon for lez142-