National Weather Service Weather Forecast Office

• Home
• Site Map
• News
• Organization
• Search for: NWS All NOAA 

-- Discussion containing changed information from previous version are highlighted. --
000
FXUS61 KCLE 150502
AFDCLE

Area Forecast Discussion
National Weather Service Cleveland OH
102 AM EDT Tue Oct 15 2019

.SYNOPSIS...
High pressure will move east across the area tonight and off the New
Jersey coast Tuesday.  Low pressure will move east across the
central Great Lakes and deepen rapidly by Wednesday evening.  A
strong cold front will move east across the area Tuesday night.
Another low pressure will develop off the Carolina coast Wednesday
and rapidly intensify as it absorbs the Great Lakes low pressure
system.  The combined low center will move northeast along the coast
High pressure will move slowly east to the local area by Friday.

&&

.NEAR TERM /THROUGH TODAY/...
As expected, the lake-effect cloud band is shifting northward
over/near the Lake Erie shore from Lake County to Erie County,
PA. Expect these clouds to be totally offshore by daybreak
Tuesday as the mean steering flow continues backing from west-
southwesterly to southwesterly. Elsewhere in our CWA, mainly
clear skies, very light or calm winds, and limited humidity will
promote efficient radiational cooling through daybreak Tuesday.
Decreased forecast low temperatures for Tuesday morning for
inland portions of the CWA. The 10th percentile low temperatures
from all available model guidance were used for this adjustment.
Accordingly, the Frost Advisory was expanded to include the
following counties: Geauga, inland Ashtabula, Crawford County, PA,
and southern Erie County, PA. The Frost Advisory remains in effect
from 2 AM to 9 AM EDT Tuesday. Lastly, patchy fog may affect
interior portions of far-northeast OH and northwest PA between 2 AM
and 9 AM EDT Tuesday. The remainder of our near-term forecast
remains valid.

PREVIOUS DISCUSSION...A weak broad upper level ridge will move
east across the area during this forecast period. This will
result in surface high pressure that will move east across the
local area tonight. As the high pressure moves in, the lake
effect rain showers and clouds will continue to wane this
afternoon and even further tonight. The rest of the northeast
Ohio continues to see rapidly diminishing clouds as drier air
pushes into the region. Winds are expected to become very light
and variable overnight as air mass decouples. Dewpoint
temperatures upstream are in the upper 20s to lower 30s and
expecting this cooler air to move east toward the region
overnight. Therefore, expecting a widespread frost to develop
across the forecast area tonight and will hoist a frost advisory
late tonight through sunrise. Exception will be the northeast
snowbelt where the blanketing cloud cover should hang on long
enough to keep frost from forming. If they clear out much
faster, then we could see frost up there as well. Looking at
lows tonight in the middle 30s most areas and in the 40s in the
northeast.

High pressure moves east allowing moisture to advance east ahead of
the next storm system.  The low pressure system will move east
through the central Great Lakes Tuesday and force a strong cold
front east across the local area Tuesday night.  Precipitation will
move into the western portions of the forecast area by late tomorrow
afternoon.  Can`t rule out a possible rumble of thunder or two with
the front tomorrow night.  Highs in the quick warm air advection
will recover back into the 60s tomorrow and then drop back to the
middle 40s west and lower 50s east in the cold air advection.

&&

.SHORT TERM /TONIGHT THROUGH THURSDAY NIGHT/...
We begin the short term period with an upper level closed low over
southern Ontario and the associated surface pressure very close to
vertically stacked with this upper low. The cold front will be
slowly exiting to the east during the day on Wednesday, with the
associated widespread rain exiting the forecast area as well. Cold
temperatures aloft move over the lake immediately following the cold
front, with temperatures at 850mb at or slightly below freezing and
near or just above -10 Celsius at 700mb. With lake surface
temperatures around 17 to 18 degrees Celsius, that will be near 20
degrees lake sfc to 850 temperature difference. Combined with
unidirectional northwest flow and good moisture from the upper level
low, and we have ourselves a solid setup for lake effect
precipitation over Northern Ohio and Northwestern Pennsylvania. Lake
induced CAPE will be upwards of 700 J/kg, which should be enough
instability to support isolated thunderstorms as well. Moisture
lingers for quite a long time, persisting through Wednesday night
and most of Thursday. Most model guidance have low level moisture
finally pushing off to the east Thursday night, with it completely
dry by at least Friday afternoon. With high pressure building in
from the west on Friday, clouds should be clearing out most of the
day Friday. With high temperatures around 60, which will be higher
than the previous two days, it should be nice fall day.

&&

.LONG TERM /FRIDAY THROUGH MONDAY/...
With surface high pressure and the upper level ridge building in
from the west, skies should continue to become clear through the
night, with radiational cooling producing fairly cool overnight
temperatures. High pressure will have moved off to the Mid-Atlantic
by Saturday morning, allowing southerly winds to advect warmer air
into the region, bringing high temperatures back into the upper 60s
on Saturday. The pattern becomes more amplified on Sunday with a
deep upper level trough building over the plains on Sunday. This
trough will introduce the chance for widespread precipitation across
the area on Sunday night into Monday.

&&

.AVIATION /06Z Tuesday THROUGH Saturday/...
High pressure is currently over Ohio and western PA and was
drifting slowly east. Flow off Lake Erie still holding clouds
into KERI however conditions were VFR. Elsewhere, skies were
clear. Expecting low level winds to back towards morning taking
clouds offshore from KERI. Otherwise expect clear skies to
persist through afternoon before clouds begin to thicken and
lower from the west ahead of an approaching cold front. Rain
should move in from the west after 00Z with conditions
lowering to MVFR after about 04z in the west. Isolated thunder
not out of the question. MVFR conditions reach KCLE by 10Z Wed.

.OUTLOOK...Non-VFR likely overnight Tuesday night. Non-VFR
possible in lake effect rain showers at/near KERI late
Wednesday morning through Thursday and perhaps Friday morning.

&&

.MARINE...
The Small Craft Advisory will continue through this evening. Most
observations along the lakeshore are showing waves of around 4 feet
with west winds as high as 25 knots. Winds are expected to slowly
diminish this evening into tonight as high pressure builds in from
the west. As this high pressure moves east of Lake Erie and low
pressure develops over the western lakes, southerly winds increase
up to 10 to 20 knots 18Z Tuesday through 06Z Wednesday. The
aforementioned area of low pressure progresses eastward Tuesday
evening and Wednesday overnight, deepening to 998mb over Lake Huron
by 12Z Wednesday. The associated cold front will move east across
the lake on Wednesday, with fairly strong westerly winds of 20 to 25
knots immediately behind the front. A fairly strong pressure
gradient is expected to persist over the lake through at least 00Z
Friday, through which at least Small Craft Advisory conditions will
be present. Gale force winds may be possible over the open waters of
Lake Erie briefly late Wednesday night, which will largely be
dependent on how strong the low pressure will deepen to. A couple
models have the low getting to as low as 994 mb on Wednesday
afternoon. Waves of up to 10 feet may be possible late Wednesday
night over the open waters of Lake Erie. Winds will diminish through
the day on Friday as high pressure builds in from the west.
Southerly winds of 10 to 15 knots develops on Saturday as this high
pressure pushes off to the east coast.

&&

.CLE WATCHES/WARNINGS/ADVISORIES...
OH...Frost Advisory until 9 AM EDT this morning for OHZ003-006>010-
     013-014-017>023-027>033-036>038-047.
PA...Frost Advisory until 9 AM EDT this morning for PAZ002-003.
MARINE...None.

&&

$$
SYNOPSIS...Lombardy
NEAR TERM...Jaszka/Lombardy
SHORT TERM...Saunders
LONG TERM...Saunders
AVIATION...TK
MARINE...Saunders