Area Forecast Discussion
Issued by NWS Cleveland, OH

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787
FXUS61 KCLE 200158
AFDCLE

Area Forecast Discussion
National Weather Service Cleveland OH
958 PM EDT Thu Apr 19 2018

.SYNOPSIS...
A large area of high pressure will build slowly east across the
lower Great Lakes through Saturday night.  A warm front will lift
northeast to southeastern Ohio by Monday and become nearly
stationary through Wednesday morning.  Low pressure will move
northeast along the front to the Ohio Valley by Wednesday morning.

&&

.NEAR TERM /THROUGH FRIDAY NIGHT/...
Update...Removed flurries and clouds east. Dropped temps a
degree or two given clear skies and dry conditions.

Original...A quiet weather pattern is shaping up over the next
36 hours. Deep digging positively tilted upper level trough will
exit to the east by the weekend as a large ridge of high
pressure builds east out of the Plains states. The upper level
ridge will support a large surface high pressure that will move
slowly east across the southern Great Lakes region. The surface
high pressure will be the dominating weather feature across the
area over the next 36 hours.

However, in the mean time, some residual lake effect snow showers
will continue across northwest Pennsylvania as the mean flow drops
south out of Lake Huron across Lake Erie into the local area. Strong
subsidence and drier air will push east into the forecast area
tonight and this should bring an end to the threat for
precipitation.  Residual diurnal cloud cover in place at this time
will begin to diminish near and after sunset over much of the area
this evening due the drier air.  As mentioned earlier, the exception
is northeast portions of the forecast area.

Gradient will begin to weaken a bit and decoupling will occur to
allow winds to diminish overnight to 10 mph or less across the area.
Winds will stay up around 10 to 12 knots along the Erie county
Pennsylvania shore.

&&

.SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
High pressure this weekend with ridging aloft will support
quiet weather over the region. The primary forecast challenge
will be temperatures for lakeshore counties. H850 temperatures
remain around 0-2C for both Saturday and Sunday, cool for this
time of year. On Saturday the flow will be light and out of the
north, turning northeast by Sunday. The intrusion of the
maritime air will create a tight temperature gradient within
those lakeshore counties. Moisture will be limited but can`t
rule out some afternoon clouds, especially west. Lows will fall
back into the 30s each night, likely supporting a frost Saturday
Night if skies remain clear.

By Sunday Night the pattern begins to shift. A deepening low over
the Gulf States will move east, with the surface high over the Great
Lakes moving into New England. The flow out of the SE will warm H850
to around 6C, with increasing thicknesses aloft. Temperatures Monday
will likely reach the mid to upper 60s before moisture/clouds begin
to move in Monday Night. The large temperature gradient between
inland and the lake (lake T in the lower 40s), combined with
relatively light se winds, will favor an afternoon lake breeze.

&&

.LONG TERM /MONDAY THROUGH THURSDAY/...
Leaned closer to the ECMWF solution which brings more
consistency with the WPC progs. Basically we are dealing with a
closed low/open wave moving across the TN/OH Valley for mid week
and then the evolution of Pacific NW and Canadian shortwave
energy across the Upper Midwest/Great Lakes. Will keep the
forecast largely dry for Tuesday with the southern track of the
first system. But with an approaching cold front from the
northwest for Wednesday have continued the chance PoPs. Then
banking on high pressure toward Thursday. Overall temperatures
will run close to seasonal norms.

&&

.AVIATION /00Z Friday THROUGH Tuesday/...
Building high pressure and dry air across northern Ohio and
northwest PA this evening. Models show a little moisture backing
up into the area from the east but for now have kept KERI and
KYNG VFR through the night. Expect VFR and mostly clear skies to
persist on Friday as well.

OUTLOOK...VFR.

&&

.MARINE...
Have allowed the central portion of the small craft advisory to
expire on schedule and have trimmed the eastern portion back to
4 am. Winds are diminishing this evening and waves will follow
shortly thereafter.

Previous discussion...Lake Erie was situated between surface
high pressure over the upper plains and low pressure off New
England at the time of this issuance. The tight gradient between
these features was shifting east into PA/NY allowing winds to
relax starting in the western basin. Will drop the small craft
for the far western marine zones, with improving conditions from
west to east this evening. The NW flow has produced waves
around 4-6 feet, highest east, that will take through late
tonight to recede. The surface high will build over the region
Friday and linger into Sunday supporting favorable conditions on
the lake into early next week.

&&

.CLE WATCHES/WARNINGS/ADVISORIES...
OH...None.
PA...None.
MARINE...Small Craft Advisory until 4 AM EDT Friday for LEZ146>149.

&&

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



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