FXUS61 KCLE 201325
AFDCLE

Area Forecast Discussion
National Weather Service Cleveland OH
925 AM EDT Tue May 20 2025

.SYNOPSIS...
Low pressure moving into the region brings a period of off and
on showers for mid week, with persistent upper level troughing
keeping conditions unsettled through the end of the week and 
into the weekend.

&&

.NEAR TERM /THROUGH WEDNESDAY/...
9:25 AM Update...
Forecast remains on track this morning with minor adjustments
made to temperatures, dew points, sky cover, and PoPs to reflect
current conditions. 

620 AM Update...
Made some updates to the onset of the POPs today that more fine
tuned the progression rather than consisting of major changes.
Onset in this airmass is going to be naturally slowed slightly
due to wet bulbing on the front end. Also gave the afternoon
high temperatures some TLC as well.

Previous Discussion...
Weak ridging quickly exits, giving way to southwesterly flow aloft, 
a trough axis moving southwest to northeast, and positive vorticity 
advection into the western zones after 15Z Tuesday. This will start 
the first of the POPs into the CWA with the patchy vorticity aloft. 
A well defined area of frontogenesis will develop with the trough 
axis itself a few hours later and becomes the primary source of 
forcing for shower activity after 18Z. With the track of the 
associated surface low west to east south of the area, the main 
thunderstorm threat should stay south with the warm sector that will 
not make it to our CWA. Shower activity will become more scattered 
beyond 06Z Wednesday with another upper level trough axis in the 
area and the surface low departing to the east. Total QPF through 
Wednesday pushes an inch and a half in the southeastern zones. This 
low pressure system will also reinforce the northerly winds in the 
region with high pressure moving into western Lake Superior and the 
cooler temperatures. Temperatures in the upper 50s to upper 60s 
Tuesday into Wednesday.

&&

.SHORT TERM /WEDNESDAY NIGHT THROUGH FRIDAY NIGHT/...
A surface low will continue to meander across the area Wednesday 
night into Thursday, eventually settling near the Mid-Atlantic Coast 
by Friday. Once the low shifts towards the coast, a surface trough 
is expected to linger across the area through the remainder of the 
short term period. A series of shortwave upper-level troughs will 
move along the periphery of the larger trough, bringing additional 
support across the area for widespread showers to persist through 
Friday. There will likely be periodic breaks in precipitation 
Thursday night as the center of the low and areas of subsidence 
progress east directly over the area. By Friday night, models are in 
decent agreement that the center of the aforementioned low will 
shift east of the area, allowing for a surface trough to linger. As 
a northwest flow develops with this trough, 850mb temperatures of 
-1 to 0C will push over a relatively warm lake (14 to 15C) will
 result in weak lake induced instability and allow to a
 transition of lake enhanced rain showers Friday night. When all
 is said and done, most of the area should see between 0.25-0.5"
 of new precipitation during the short term period, with higher
 totals across the eastern portion of the area. Locally higher
 amounts are possible where persistent lake enhanced showers
 occur or within any convection that develops. Overall, little
 to no impacts should be observed from these showers. High
 temperatures through the period will be below average, climbing
 into the 50s both days. Overnight lows will gradually cool from
 the upper 40s to low 50s Wednesday night to the low to mid 40s
 Friday night.

&&

.LONG TERM /SATURDAY THROUGH MONDAY/...
On Saturday, lingering showers are possible, especially across the 
eastern portion of the CWA as a surface trough slowly drift east. 
Overall moisture this weekend will diminish, allowing for any 
showers activity to dwindle to isolated to scattered showers at 
best. Not expecting a complete wash out this weekend unless the 
aforementioned low pressure system slows its progression east. By 
Saturday night into Sunday/Monday, models continue to suggest a weak 
high pressure system and associated ridge building over the area, 
allowing for a period of predominately dry conditions. There remains 
quite a bit of uncertainty on the timing of the high settling over 
the area, so opted for some slight chance to chance shower mention 
through Monday, with highest probability focused in the afternoon 
hours. Highs over the weekend will gradually warm from the low to 
mid 60s on Saturday into the upper 60s to low 70s on Monday. 
Overnight lows will linger in the 40s.

&&

.AVIATION /12Z Tuesday THROUGH Saturday/...
With an area of low pressure moving into the region and a warm
front sitting to the southwest, precipitation chances and
coverage will be on the increase after 18Z, and later further
east. Expect deteriorating conditions as the atmosphere
saturates in shower activity today, with MVFR ceilings dropping
to IFR for all terminals for several hours in the latter half 
of the TAF. Went a little more conservative with the
visibilities in rain and primarily kept those MVFR. East winds
10-15kts. Left thunder out of the forecast as well but isolated
thunder could be in the area.

Outlook...Non-VFR expected with periodic rain showers and
isolated thunderstorms later Wednesday through Saturday.

&&

.MARINE...
Low pressure currently centered over the Midwest will gradually push 
east into the Ohio River Valley today and linger into Friday. The 
initial positioning of the low will allow for increase winds from 
the northeast today to 15-25 knots. These winds will result in waves 
building to 4-6 feet, with the highest waves across the central and 
western basins. As a result, a Small Craft Advisory has been issued 
through Wednesday for the western basin and with this update has 
been expected to include the central basin as well. As the center of 
the low becomes centered near Lake Erie, winds will gradually weaken 
and rotate to become sustained from the northwest by Thursday 
morning. Winds will gradually increase to 15-20 knots late Thursday 
into Friday. This period will be marginal for any headlines needed, 
although given the onshore flow, cannot rule out the need of a short 
duration Small Craft Advisory late Thursday through Friday. A trough 
will linger into the weekend before high pressure builds across the 
lake sometime this weekend. Expect winds of 5-10 knots to persist 
across Lake Erie through this weekend.

&&

.CLE WATCHES/WARNINGS/ADVISORIES...
OH...None.
PA...None.
MARINE...Small Craft Advisory until 10 PM EDT Wednesday for LEZ142>144.
     Small Craft Advisory from 2 PM this afternoon to 10 PM EDT 
     Wednesday for LEZ145-146.

&&

$$

SYNOPSIS...26
NEAR TERM...13/26
SHORT TERM...04
LONG TERM...04
AVIATION...26
MARINE...04