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-- Discussion containing changed information from previous version are highlighted. --
000
FXUS61 KCLE 210508
AFDCLE

Area Forecast Discussion
National Weather Service Cleveland OH
108 AM EDT Tue Aug 21 2018

.SYNOPSIS...
Low pressure over Iowa will move northeast to the central Great
Lakes by late Tuesday afternoon. A warm front from the low will
lift north across the local area tonight. The low will pass to
the north of the local area tomorrow evening forcing a strong
cold front across the region by early Wednesday.

&&

.NEAR TERM /THROUGH TODAY/...
No big changes with the mid evening update. The line of showers
and thunderstorms continues to weaken and become more broken in
nature as was expected. Lightning has fallen way back too. But
the warm front will continue to lift north through the night and
this would spark a few showers or a rumble of thunder so the
forecast for the rest of tonight remains largely intact with
this early evening update. Relevant portions of previous
discussion follows...Most locations will see a 2 or 3 hour
window of precip. By the time it reaches the eastern end of the
area the line may be broken or scattered in nature. A second
wave of precip will arrive in the west prior to daybreak as the
surface low heads towards the area. Will need high pops all
areas tomorrow but am not expecting an all day rain. Most
locations will probably see 2 periods of precip during the day.
Still some concern about severe weather at the east end of the
area tomorrow afternoon and evening ahead of an approaching cold
front. A lot of that will depend on how precip and cloudiness
there is earlier in the day. The front will be out of the area
by midnight and the precip will end from from west to east
beginning in the west. By daybreak Wednesday only the eastern
tip of the area could still have precip.

Have stayed close to guidance for temps during the period. There
will be a significant airmass change behind the front tomorrow
night.

&&

.SHORT TERM /TONIGHT THROUGH THURSDAY NIGHT/...
The cold front will be pushing east of the area on Wednesday, with a
secondary front enhancing the cold air advection expected by the
evening. The thicknesses will drop notably with H850 around 9C and
H500 around -17C. Despite the drier air moving in, the lake induced
capes will support lake effect clouds and showers. This will bring
extensive cloud cover to the downwind (NW winds) side of the lakes.
Temperatures will struggle to reach the lower 70s as a result.
Expect mainly showers though couldn`t rule out a stray thunderstorm.
The high pressure will build in overnight and into Thursday. This
will rapidly erode any lake effect and lead to mostly sunny
conditions for Thursday. Temperatures will moderate slightly, with
more warming expected Friday with the return of southerly flow.
Temperatures will be primarily in the 70s with lows in the 50s for
most of the area.

&&

.LONG TERM /FRIDAY THROUGH MONDAY/...
The models show an upper level short wave and surface cold
front moving into the region late Friday night. This cold front
is forecast to slowly move across the forecast area on Saturday.
Scattered showers and thunderstorms will be possible late
Friday night through Saturday as this front moves through the
region. A weak short wave will move through the upper level flow
over Great Lakes region on Sunday. This will create enough lift
and instability to keep showers and a few thunderstorms over
the area.

&&

.AVIATION /06Z Tuesday THROUGH Saturday/...
Surface low over northern IL early today with moist southerly
flow into northern OH. Radar showing showers and embedded
thunder moving nne into northeast OH and will eventually reach
into nwrn PA as well. Another area of showers/thunder will
similarly move into northwestern OH affecting KFDY and KTOL
terminals through the next couple hours. After that, it becomes
difficult to pin down individual areas of precip/thunder but
showers and thunderstorms should be expected across the region
much of the period as the low moves northeast across the central
Great Lakes through the day. Am expecting VFR CIGS to lower to
MVFR around sunrise then lift through the morning back to VFR
however any showers/thunderstorms will yield MVFR or IFR
conditions.

OUTLOOK...Non-VFR possible in showers and thunderstorms
Tuesday night into early Wednesday. Non-VFR possible Saturday.

&&

.MARINE...
Small Craft Conditions likely from Conneaut OH-Ripley NY. As an area
of low pressure approaches the area from the west the low level jet
will strengthen to around 35knots out of the southeast. With the
downsloping component of the higher terrain in NW PA expect 10m
winds around 20 to 25 knots with gusts around 30-35kt around Presque
Isle. The southeast component will last from this evening through
Tuesday morning. Once winds switch to the south mixing will be
reduced and speeds will moderate to around 15-20 knots. The waves
will build to around 4 feet in the near shore overnight as a result.
Conditions are expected to remain just below small craft levels in
the near shore on Tuesday as sw winds around 15-20 knots bring the
higher waves into the open waters. As the low exits the area a cold
front will move across the waters turning winds to the north for
Wednesday  morning. A secondary cold front with more cold air
advection will kick in Wednesday evening, which when combined with
fetch should result in small craft conditions. Conditions will
rapidly improve as strong high pressure builds in on Thursday into
Friday.

&&

.CLE WATCHES/WARNINGS/ADVISORIES...
OH...None.
PA...None.
MARINE...Small Craft Advisory until 11 AM EDT this morning for LEZ149.

&&

$$
SYNOPSIS...Kubina
NEAR TERM...Kubina/Oudeman
SHORT TERM...Jamison
LONG TERM...Garnet
AVIATION...TK
MARINE...Jamison