Area Forecast Discussion
Issued by NWS Cleveland, OH
FXUS61 KCLE 241345
Area Forecast Discussion
National Weather Service Cleveland OH
945 AM EDT SAT SEP 24 2016
High pressure located over Ontario will build south today and
remain in place over the eastern Great Lakes through Sunday. A
cold front moving through the central United States will move
through the midwest late on Sunday, eventually reaching the Ohio
Valley on Monday. Low pressure from Canada will then shift south
behind the cold front on Tuesday, settling in over the Great Lakes
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
Limited tweaks to the forecast for today with this mid morning
update. Lowered temps by just a couple of degrees. Most places
have hit their low spot for the day and will slowly climb from
Original Near Term Discussion...
A fantastic first Saturday of Fall is in store for northern Ohio
and northwest Pennsylvania today. A broad upper ridge is
supporting surface high pressure over Ontario. Northerly flow will
allow for colder air to move in and temperatures to return to
normal for the last weekend of September. Meaning...yes, the
stretch of 10-15 degree above normal/80 degree highs will be
broken today with temperatures in the 70s. Clouds will be
prevalent to start the day, but they will mix out fairly quickly
beginning from NW PA this morning to the I-75 corridor sometime
this afternoon. Although more insolation meant a significant
increase for the high temperature on Friday, the northerly wind
will keep things in check for the most part.
.SHORT TERM /6 PM THIS EVENING THROUGH TUESDAY NIGHT/...
The pattern for Saturday should continue into Sunday as high
pressure builds into the northeastern United States. The main
difference for Sunday is that winds will shift around to the east
and then southeast as the high is to the northeast and a cold
front comes in from the west. This will allow for temperatures to
creep up on Sunday a bit above average in the upper 70s with
perhaps a spot hitting the 80 degree mark, but still a pleasant
dry day with plenty of sunshine due to high pressure.
On Sunday night, clouds will be on the increase as a cold front
approaches from the west for Monday. The models are in really
good agreement on the timing of the front with precipitation
beginning in areas west of I-71 in the morning and areas east of
I-71 in the afternoon. The front itself looks to clear the I-75
corridor by late afternoon into early evening and then the entire
CWA in the early hours of Tuesday morning and have introduced
likely POPs into the forecast based on the timing of the front.
Have put in a chance of a thunderstorm as well, not very convinced
that there will be thunder as the area won`t get that all that
unstable ahead of the front, as temperatures will only be in the
low 70s with lots of cloud cover, but with a strong front and
upper trough to support convection, it is worth a chance mention.
Behind the front, some lingering lake-effect showers appear
possible for northeast Ohio and NW PA for Tuesday with a much
cooler air mass and westerly/northwesterly wind behind the front
over a warm Lake Erie. The surface low associated with Monday`s
cold front will also drift southward on Tuesday into the Great
Lakes region so some residual rain could still develop, although
most of that looks to stay north of the area for now. Temperatures
on Tuesday look to be a couple degrees below normal behind the
front and could potentially be lowered another degree or two by
the time Tuesday arrives. It certainly looks like fall is finally
.LONG TERM /WEDNESDAY THROUGH FRIDAY/...
The trough aloft is progged to move across the Great Lakes mid
week. The ECMWF continues to develop a closed low while the GFS
and CMC have a deep trough but are more progressive. Either
solution results in a chance of instability and lake effect
showers Wednesday into Wednesday night, probably the best chance
in the snowbelt. Not sure whether the showers will be east of the
area on Thursday. The 00Z ECMWF keeps the closed low through the
end of the week which seems to be an outlier. Most of the guidance
and continuity trends dry Thursday and will stick with the current
forecast of dry weather from Thursday on as high pressure begins
to build in.
Temperatures are tricky mainly with respect on the amount of cloud
cover and showers. If it gets cloudy quickly on Wednesday and showers
develop then temperatures will go no where. If it takes a while for
the instability showers to develop then temperatures can warm into
the mid 60s Wednesday. Will not forecast the worst case scenario and
continue with lower/mid 60s on Wednesday, lower/mid 60s to near 70
northwest Ohio on Thursday, then a few degrees warmer Friday.
.AVIATION /12Z Saturday THROUGH Wednesday/...
Ceilings will continue to rise as drier air filters in this
morning. The cloud deck will evolve into VFR fair weather cumulus
and the clouds will eventually clear during the afternoon as
subsidence increases. Northeast winds will be a bit gusty mainly
near the Lake Erie lakeshore. Generally clear tonight except for patchy
lake effect clouds that may clip the lakeshore between KCLE and
OUTLOOK...Non-VFR possible Monday and Monday night in showers.
The northeast winds will gradually diminish today as the surface high
builds across the eastern Great Lakes. Unfortunately the long
northeast fetch typically means that the winds and waves on the
western two thirds of the lake persist longer than guidance would
indicate. Will extend the small craft advisory until 4 PM to give the
lake time to settle down.
High pressure will be east of the lake on Sunday with the easterly
flow veering southeast. The west half of the lake will likely remain
a bit choppy.
The next cold front will cross the lake on Monday. It is a stronger
front and southwest winds will ramp up quickly. A small craft
advisory will be needed again monday into Tuesday.
MARINE...Small Craft Advisory until 4 PM EDT this afternoon for