Area Forecast Discussion
Issued by NWS Cleveland, OH

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FXUS61 KCLE 081048

Area Forecast Discussion
National Weather Service Cleveland OH
648 AM EDT Sat May 8 2021

High pressure will briefly build in across the Great Lakes
region today. Low pressure will develop to the lee of the
Rockies later today and move northeast into the Ohio Valley for
Sunday and Sunday night. A trough will linger across the region
behind this low on Monday. A cold front will move through the
region on Tuesday. High pressure will build into the region for


Showers continue across far Northeast Ohio and Northwest PA
this morning as cold front continues east across the eastern
Great Lakes in a supportive northwest flow regime. Showers may
linger through a good portion of the day in NW PA with moisture
off the lakes and have extended chance PoPs through early this
afternoon. Surface high pressure and some upper level ridging
will nudge the trough and northwest flow east later in the day,
allowing for clearing conditions for most folks. With a similar
trend to Friday, have largely matched high temperatures for
Saturday with 50s for most and 40s in NW PA with the lingering
rain. For tonight, clearing skies and light winds will persist
across NW PA and there will be a brief period tonight for frost
before clouds roll in late. Have issued a Frost Advisory for
southern Erie and Crawford counties. Lows in NW PA and NE OH
will be in the 30s with 40s elsewhere.

For late tonight into Sunday, all attention will be on the
approach of low pressure moving across the central United
States. The warm front will push towards the Ohio River late
tonight, bringing increasing clouds to the region. The 850 mb
warm front will be across central Ohio by daybreak on Sunday and
will be the key piece in widespread rainfall on Sunday. This
feature will bring in deep, Gulf moisture and with forecast
soundings across the region showing precipitable water values
around an inch, this will allow for periods of moderate to heavy
rainfall. It will take most of the day for the low pressure
center to reach Ohio and therefore, expect rain all day and have
maintained high PoPs. The tricky part of the forecast will be
temperatures. Temperatures will start cool in the lower 40s for
most and with rain all day, don`t expect much of an increase
through the day, but those that escape the early rain could
quickly see their highs Sunday morning. Warm air advection near
the surface will be late on Sunday and some of the southern
counties could see their highs late, perhaps getting into the
50s. Instability will be limited across the region and thunder
chances will be low, will keep thunder chances slight at best
for most with chance thunder far south closer to the front on
Sunday afternoon.


Low pressure will move eastward across PA Sunday night with rain
gradually ending from west to east. All locations should be dry by
sunrise on Monday. If clouds decrease fast enough Monday night with
the winds we could have frost across a large portion of the region
away from the lake. We then will be watching an upper level trough
that will pivot across the central Great Lakes Monday night into
Tuesday. Cooler air aloft and a reinforcing cold front will move
across the region Tuesday afternoon. Cooler air aloft and flow
across the lake should result in showers across NE OH into NW PA.
Cant rule out a little bit of thunder and maybe some small hail with
the strongest convection that develops. High pressure takes control
from the west Tuesday night with dry conditions in the wake of the
evening showers. Winds decrease with the cloud cover Tuesday night
with a very good chance of frost for inland locations.

Continued cool temperatures through the short term. Highs ranging
from the upper 40`s to maybe 60. Lows in the mid 30`s to around


Models diverge significantly in the long term with the GFS the
outlier again this morning as it brings low pressure across Ohio
Thursday into Friday. Have once again leaned heavily on the
Canadian/ECMWF models for the long term. So with that said it looks
as if high pressure will control the region Wednesday through
Thursday night. Wanted to go below slight chance POP`s Thursday into
Friday but didn`t want to flip-flop the forecast to much.
However we are leaning toward a dry forecast at this point in

Highs gradually warm through the long term period. Mid 50`s to mid
60`s common on Wednesday, then warming to the 60`s to near 70 on
Friday. Still chilly Wedneday night with frost possible east.
Otherwise lows will be in the 40`s for Thursday and Friday


.AVIATION /12Z Saturday THROUGH Wednesday/...
Aviation conditions across the region are a mixed bag with VFR
to IFR at terminals this morning. Low clouds and scattered rain
showers are present and where rain moves through low MVFR or IFR
will occur at the terminal. Main confidence with rain this
morning is at KERI where a band of rain coming from the west
will allow for more pessimistic conditions. Elsewhere, ceilings
have bounced around all morning. The mean is MVFR and will
maintain that in the TAFs through early afternoon. Clouds have
expanded slightly westward towards KTOL and KFDY this morning
and have added a brief MVFR mention there. High pressure will
briefly enter later today and a dry wedge of air will allow for
ceilings to scatter with a trend to VFR for all sites. All
attention then turns to an incoming low pressure system and have
begun rain and non-VFR mentions for KCLE and west late in the
TAF period. Winds today will primarily be out of the northwest
and will switch around to the south late with the system for

Outlook...Non-VFR conditions possible within widespread rain
Sunday and Sunday night.


A cold front will cross the east end of the lake through sunrise.
Northerly winds in the wake of the front will be around 20 knots.
This should support waves of around 4 feet from the western basin to
Geneva on the lake. So the current small craft advisory looks
reasonable. Winds begin to to decrease through the day and shift to
the west and southwest. Speeds hover near 15 knots and will
gradually build waves from Conneaut to Ripley. Current thinking is
that waves remain in the 2 to 4 foot range. However if wind speeds
end up being closer to 20 knots we will need a short duration small
craft advisory for the PA waters.

A stronger area of low pressure will move eastward near the Ohio
River Valley on Sunday with northeast to east winds developing. The
strongest of the winds should occur Sunday afternoon and evening.
Waves in excess of 4 feet are expected for the western 2/3rds of the
lake. As the low moves east of the region Sunday night winds
shift to the north and slowly decrease. Will likely need a small
craft advisory starting by Sunday afternoon then continue into
Monday morning. Northerly winds should persist into Tuesday
morning but speeds should decrease. A surface trough will linger
near the lake on Tuesday then a reinforcing surge of cooler air
pushes southward across the lake by Tuesday afternoon. Will
have to monitor for stronger northwest winds in the wake of the
trough for a few hours Tuesday afternoon into the evening.


PA...Frost Advisory from midnight tonight to 8 AM EDT Sunday for
MARINE...Small Craft Advisory until 11 AM EDT this morning for
     Small Craft Advisory until 2 PM EDT this afternoon for


NEAR TERM...Sefcovic
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