Area Forecast Discussion
Issued by NWS Cleveland, OH

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FXUS61 KCLE 222346

Area Forecast Discussion
National Weather Service Cleveland OH
746 PM EDT Mon May 22 2017

High pressure over the Ohio Valley will move off the east coast
on Tuesday. The next storm system will slowly move from the
Mississippi Valley across the Great Lakes Wednesday and
Thursday. High pressure will build in briefly Friday into
Saturday but another cold front is due this weekend.


Only minor adjustments were made to the forecast as fair weather
prevails across the region as high pressure slowly shifts away
from the region. Cirrus over mainly the east half of the area
will thin for the next several hours and then increase as more
clouds associated with a short wave rounding the base of a
trough over the south central states shifts towards the middle
Atlantic states. More clouds over the mid Mississippi Valley
will spread into nw Ohio this evening as another short wave near
nw Iowa digs southeast toward se Iowa by morning. Current
temperature forecast looks reasonable.

Previous discussion...
High pressure at the surface is progged to slide off to the east
tonight. Winds will likely become light and variable although the
south wind may continue 4-6 knots near the lakeshore. We will start
with a little cirrus and there will likely be a tendency for the
cirrus to increase. Some altocumulus will likely develop across
northwest Ohio before daybreak as a short wave rounds the bottom of
the trough and heads toward the central Great Lakes.

Given the lighter winds and patchy high clouds, we should have
enough radiational cooling tonight to get relatively chilly.
Forecast lows will range from the mid 40s in the cooler spots (with
some low 40s eastern Erie and Crawford Counties PA) to around 50


The short wave should track across the central Great Lakes on
Tuesday. There has been a trend among most of the models to lower
the shower threat across northwest Ohio for Tuesday. The air mass is
relatively dry and stable. The only thing that makes me nervous is
that we will be in the right entrance region of the jet on Tuesday
but I suspect that we would see a little virga rather than rain with
varying amounts of mid and high clouds. With 850 mb temps about 9-
10C and at least partial sunshine, we should be good for highs in
the lower to mid 70s.

The models are in surprisingly good agreement with the upper
features of the developing storm system midweek. A strong short
wave will carve the trough deeply into the Mississippi Valley on
Wednesday. The jet on the east side of the trough is
essentially progged to couple with the jet across the Great
Lakes. A broad area of upward motion will likely develop from
the lower Ohio Valley to the lower Great Lakes. A surface low
will develop within this zone and drift north until it gets
stacked within the upper trough and stalls. Not sure how fast
the showers will spread east but there certainly seems a good
chance for showers across northwest and north central Ohio. Will
also mention thunder. Instability will probably not be too
impressive but with the strong upward motion this time of year
there will probably be at least some embedded thunder. High
temperatures depend on how quickly the rain develops. Will have
higher forecast highs across NE OH and NW PA where the showers
will take longer to develop.

By Thursday, the upper low/trough is progged to be overhead.
Showers will likely be more random. There could be a dry slot
but it is too early to try and get that specific with the
forecast. High temperatures will likely be in the 60s. Lower 60s
if there are enough showers, mid/upper 60s with enough dry


Active pattern setting up with waves through every couple of
days. Forecast problem is the timing since ECMWF and GFS
continue to differ on timing of the systems. Both models has
system exiting the area Friday with some lingering showers in
the East. After that models diverge. The ECMWF has next low
moving across Southern Ohio Saturday with the second wave moving
across the forecast area on Sunday. The GFS has the same trend
but the models is 6-8 hours faster. Leaned toward the slower
ECMWF simply because models have been a little fast on the
timing of the systems recently.


.AVIATION /00Z Tuesday THROUGH Saturday/...
VFR through the TAF period. High pressure will shift east
tonight with light winds coming around to the south and then
east Tuesday afternoon. Expect a lake breeze for ERI and CLE
Tuesday. Next low pressure center will approach from the mid-
Mississippi Valley for Wednesday. Terminals will be on the
fringes of a mid deck by 00Z Wed.

OUTLOOK...Non-VFR likely Wednesday and Thursday in showers and


Winds are slowly diminishing as the surface ridge moves into the
Upper Ohio Valley.

Cold front has moved through most of Lake Erie early this morning,
with westerly winds from the western basin east through about Erie.
West southwest flow will increase across the lake through the day in
the 15-20 knot range before tapering off late this afternoon into
this evening from west to east. Winds will become southerly 10 knots
or less tonight becoming easterly Tuesday as low pressure pulls
northeast away from the Great Lakes and high pressure moves quickly
east across the region. Flow will be 10 knots or less through
Tuesday night, but will increase a bit out of the north Wednesday
and low pressure deepens and moves north across the lake by
Wednesday night.


OH...Beach Hazards Statement until 9 PM EDT this evening for OHZ012-
PA...Beach Hazards Statement until 9 PM EDT this evening for PAZ001.
MARINE...Small Craft Advisory until 9 PM EDT this evening for


NEAR TERM...LaPlante
SHORT TERM...Kosarik
MARINE...DJB is the U.S. government's official web portal to all federal, state and local government web resources and services.