Scientific Forecaster Discussion
fxus61 kcle 201014
Area forecast discussion
National Weather Service Cleveland Ohio
614 am EDT sun Oct 20 2019
weak surface ridging will extend from high pressure over New England
and vicinity for the rest of this weekend. On Monday, a surface low
will track northeastward over the upper Midwest to near Lake
Superior and then track north-northeastward over northern Ontario on
Tuesday. A warm front associated with this low lifts northward over
our region Monday evening through early Tuesday morning, while the
cold front sweeps east through the local area late Monday evening
through Tuesday morning.
Near term /through Monday/...
our near-term forecast remains valid. No changes were made at
A weak shortwave trough advances northeastward over Northern Ohio and
northwest PA between roughly daybreak and early afternoon today.
Behind this disturbance, a shortwave ridge will begin crossing our
County Warning Area generally from west to east. At the surface, a weak cold front
approaching from the west will dissipate over far western-Ohio late
this morning and fail to reach our County Warning Area. Otherwise, weak surface high
pressure persists. Gradual surface pressure falls begin tonight and
continue through Monday. These pressure falls will be in response to
a strengthening surface low tracking from in vicinity of the South Dakota/NE
border to near Western Lake Superior this evening through Monday.
Simultaneously, flow aloft becomes progressively southwesterly as
the aforementioned shortwave ridge exits our County Warning Area and a longwave
trough approaches from the central U.S.
Mostly cloudy skies this morning become partly cloudy this afternoon
as the aforementioned shortwave trough exits the region. Model
soundings show very dry air between the surface and the mid- to
upper-level clouds associated with the shortwave trough. Thus, any
precipitation accompanying this disturbance should fall as virga.
Surface winds will be light today with afternoon highs reaching the
mid 60's to 70 degrees. A lake breeze is still expected to develop
off relatively-Cool Lake Erie this afternoon and early evening. This
lake breeze will affect locations along and several miles inland
from the shore, including Cleveland and Erie. Dry weather will
continue tonight and through much of Monday morning as cloud cover
increases from the west and southeasterly surface breezes develop.
Low temperatures reach the mid 40's to mid 50's around daybreak
Monday. These readings will be warmest along the Lakeshore and
coolest well inland in northeast Ohio and northwest PA. The potential
of scattered rain showers increases from west to east between about
midday and nightfall on Monday. This increase in pops results from a
warm conveyor belt overspreading our County Warning Area from the west. The warm
conveyor belt is expected to undergo isentropic lift and draw large
amounts of moisture northward from the Gulf of Mexico. Despite the
increasing cloud cover, southeasterly surface winds resulting in
warm advection region-wide and downslope flow in some locations
should allow afternoon highs to reach the upper 60's to lower
70's. Thus, temperatures are forecast to trend above-normal.
Short term /Monday night through Wednesday night/...
rain showers will be upon US Monday night and with overall increased
confidence have further increased those precip chances. The cold
front will move east, possibly slowing some before morning as
another piece of energy rounds the base of the upper trough. If that
slows the front even more, then pops may have to be increased
Tuesday morning across the east half of the area. Temperatures
behind this front will be more seasonable. The wrap around moisture
largely stays north of the area as the low tracks toward James Bay
and begins to fill. The cooler west-southwest flow will generate
some showers off the lake just offshore and possibly skimming the
immediate Lakeshore Tuesday/Tuesday night. Overall a somewhat breezy
period from Monday afternoon through Wednesday evening. The flow
backs Wednesday as high pressure across the Gulf Coast states and Tennessee
Valley shifts east to the southern/central Appalachians. The brief
ridging will provide dry weather for the forecast area Wednesday.
Again seasonable temperatures
Long term /Thursday through Saturday/...
a pair of shortwaves will cross the upper Midwest and Great Lakes
Thursday into Friday. At the surface a weak cold front will cross.
There is some spread on the depth and therefore timing of the second
shortwave and therefore still have a broad mention of shower chances
Friday/Friday night, but this could arrive as early as
Thursday/Thursday night. The overall pattern would favor high
pressure for Saturday. Already this is a slight shift from the
previous forecast. No drastic swings in temperature at least through
Aviation /12z Sunday through Thursday/...
VFR expected next 24-hours. Abundant mid- to upper-level cloud
cover associated with a weak disturbance aloft will continue
exiting the region to the east through about 19z/sun. Scattered
to broken stratocumulus and cumulus are also expected during
this taf period. At the surface, a weak high pressure ridge
persists. Regional surface winds should trend light and variable
through about 00z/Mon and then become southeasterly at about 5
to 10 knots thereafter. However, a lake breeze of about 10 knots
should affect kcle and Keri for a time this afternoon and early
evening. This lake breeze should mainly be northwesterly to
northerly for wind direction.
Outlook...non-VFR possible in showers late Monday morning
through Tuesday morning. Non-VFR possible in lake-effect rain
showers at/near Keri Tuesday evening into Wednesday.
the remainder of the weekend will be quiet as the weakest of cold
fronts dissipates across the area. Winds will be light and favor an
onshore component this afternoon. Southeast winds begin to increase
toward Monday morning and through the day Monday as warm front lifts
northeast and is followed closely by the cold front for Monday
night. The low will stay well northwest of Lake Erie across the
northern lakes and the flow behind the cold front will be more west-
southwesterly through Wednesday. Winds will Max out around 20 to 25
knots although there may be a period or two with winds somewhat
stronger. High pressure builds across the Ohio/Tennessee valleys Wednesday
and shifts to the East Coast Thursday. This will back winds to the
south-southwest. A Small Craft Advisory will be needed for Tuesday
into Wednesday evening. It is still questionable if one will be
needed Monday night for the downslope flow off of PA.