Scientific Forecaster Discussion
fxus61 kcle 210122
Area forecast discussion
National Weather Service Cleveland Ohio
922 PM EDT Fri Sep 20 2019
high pressure over the Carolinas continues to extend back into
the Great Lakes region. A cold front will enter the Great Lakes
region on Sunday and push the area of high pressure off the East
Coast. The cold front clears the area on Monday and high
pressure returns to the Ohio Valley in its wake on Tuesday.
Near term /through Saturday night/...
update...adjusted hourly temps and also extended the slight
chance pop south for another hour or two with isolated
convection in the vicinity. No other changes.
Original...the area will remain under the influence of high
pressure through the duration of the near term forecast. On the
back side of the high, some elevated moisture has advected into
the region allowing for scattered cumulus development this
afternoon. With temperatures in the mid 80s, a fair amount of
instability resides in the region and a couple areas of robust
cumulus have turned into a pop-up shower. Have continued a
slight chance pop through the evening for the southern portion
of the forecast area, where the more expansive cu field remains.
Clouds will be hit or miss overnight and much of the guidance
was low on the high temperatures for today, so will go with
overnight lows a bit above guidance in the 60s.
A good surge of warm air will enter the region on Saturday, as
850 mb temperatures increase to 16-17 degrees celsius. With a
fair amount of low-level moisture remaining over the region,
this warm air advection may spur addition cloud and rain shower
development on Saturday and have a mix of slight chance to
chance pops during the day on Saturday. The coverage won't be a
wash out, but believe that there will be more showers to contend
with than this afternoon. Temperatures have the potential to be
warmer than today with highs well into the 80s, but have lowered
temps a bit from the previous forecast with the cloud and rain
potentially limiting highs in a couple spots. Saturday night
appears dry with clouds scattering out over the region.
Short term /Sunday through Monday night/...
the main feature for the short term forecast period will be a
cold front that will enter the forecast area late Sunday night
into Monday. Ahead of the cold front, the area will become well
mixed with southerly winds to 30-35 mph possible. Temperatures
will remain on the warm side well into the 80s across much of
the forecast area. Showers and thunderstorms will overspread the
region with the frontal passage on Sunday night into Monday and
the general timing for rain appears to be Northwest Ohio around dusk
and the remainder of north central and northeast Ohio sometime
after midnight. The unfavorable timing for convection will limit
both thunder and severe chances and have just a slight chance
thunder mentioned at this time. The front passes the region from
west to east on Monday and high pressure builds in from the west
on Monday night. Have quickly diminishing pops over the region
with highs on Monday likely early in the day in the lower 70s
and lows in the 50s.
Long term /Tuesday through Friday/...
the beginning of the long term forecast period appears quiet
with high pressure overhead. Temperatures will remain slightly
above normal in the 70s. The next system approaches the area on
Wednesday night into Thursday as a shortwave trough enters the
Great Lakes region. Haven't hit pops too hard yet at this time,
other than a mid-range chance. Temperatures will likely trend
high each day during the long term forecast period.
Aviation /00z Saturday through Wednesday/...
VFR conditions will continue across the area through much of the
overnight. Could see early morning fog/mist given the increase
in dewpoints so continued with just a couple hours MVFR
visibilities around dawn in a tempo group. For Saturday,
guidance did bring in MVFR ceilings mainly southeast inland but for
now, confidence is not high enough to warrant. Could see
scattered convection on Saturday however and would expect
restrictions in any weather.
Outlook...non-VFR possible in showers/thunderstorms Sunday
night through Monday.
the lake remains quiet for the next 36 hours or so as the lake
remains on the periphery of high pressure over the Carolinas.
Winds will remain light and variable out of the east to
southeast tonight before shifting around to the south on
Saturday. A cold front approaches the basin on Sunday and will
greatly increase winds over the basin with sustained winds
around 15 to 20 knots and gusts potentially up to 25 knots. The
front crosses the lake on Monday and winds will shift around to
the west and then northwest and waves will build on the
nearshore waters on Monday into Tuesday. A Small Craft Advisory
headline may be needed at this time. High pressure wobbles in
from the west on Tuesday and winds should begin to subside over
the lake, albeit from the west the through the middle of the