CLE issues Area Forecast Discussion (AFD) at Oct 30, 1:56 PM EDT952
FXUS61 KCLE 301756
AFDCLE
Area Forecast Discussion
National Weather Service Cleveland OH
156 PM EDT Wed Oct 30 2024
.SYNOPSIS...
The area will remain in the warm sector of an approaching low
pressure system until a strong cold front moves east late
Thursday into Thursday night as the low passes through the
northern Great Lakes. High pressure will build across the region
in the wake of the front Friday and persist into the weekend.
&&
.NEAR TERM /THROUGH THURSDAY/...
12:20 PM Update...
No major changes with this update.
Original Discussion...
More of the same can be expected today with record high
temperatures and gusty winds, but the pattern will start to
change Thursday as a cold front starts to move through the
region.
Infrared satellite and water vapor loops early this morning show a
deep mid/upper longwave trough remaining over the Rockies and a
downstream mid/upper ridge over the eastern CONUS. A large area of
surface ridging remains anchored along and offshore of the East
Coast. A series of shortwaves can be seen rippling through the deep
southwesterly flow between the trough and ridge, and this is
supporting weak waves of surface low pressure lifting across the
central Plains and Upper Midwest along a broad cold front/baroclinic
zone. This entire pattern will gradually shift eastward today
through Thursday, with the eastern CONUS ridge moving farther east
in response to the upstream trough filling and weakening as it
ejects across the northern Plains and Upper Midwest later today and
Thursday. This will push the cold frontal boundary slowly eastward
into the region Thursday before crossing late Thursday and Thursday
night.
For today, deep southwesterly flow and resultant warm air advection
with 850 mb temps continuing to average 12-14 C and good mixing will
continue to bring record warmth. Expect highs in the upper 70s/low
80s areawide which will tie or break records at all climate sites.
See climate section for details. The low-level jet looks a little
weaker compared to yesterday, so that will lower wind gusts
slightly. Even so, the deep mixing into the 850 mb layer will tap
into a 30-35 knot low-level jet leading to surface winds of 15-20
knots gusting to 25-30 knots from late morning through the
afternoon. The strongest wind gusts will again occur west of I-71
and along the lakeshore where the southwest direction is typically
favored. The warm conditions, well mixed profiles, and gusty winds
will again lead to afternoon RH values dipping into the 38-45%
range, especially in NW and north central Ohio, and this along with
the dry conditions could lead to fire spread. Clouds will gradually
increase tonight as the cold front approaches, and this combined
with continued southwest flow will support another very mild night
with lows in the upper 50s/low 60s.
Moving into Thursday, the weakened mid/upper trough over the Upper
Midwest looks to reamplify a bit as it ejects across the northern
and central Great Lakes in response to some phasing with a northern
stream mid/upper trough over Quebec. This will lead to a fairly
impressive 110-125 knot H3 jet streak lifting across Lower Michigan,
supporting a deepening surface low lifting across Lake Superior in
the afternoon and evening. The upper jet forcing will strengthen the
low and mid-level wind fields, with a solid 50 knot low-level jet
developing. The system continues to trend a bit slower, so this will
allow more dry time before the rain moves in which will lead to
better surface heating and resultant mixing. The end result will be
very gusty southwesterly winds of 20-25 knots, gusting to 30 to 40
knots from late morning into the afternoon. Again, the strongest
winds will be west of I-71 and along the lakeshore where a Wind
Advisory may be needed. HREF probabilities for wind gusts above 40
mph Thursday afternoon have increased to 100% west of I-71, and the
00Z HREF guidance is starting to show 25% probabilities for wind
gusts above 50 mph in NW Ohio. In terms of rain, the area will be in
the right entrance region of the aforementioned H3 jet streak, so as
the cold front moves in during the afternoon and evening, expect
widespread, steady rain given the frontogenetic forcing in response
to the jet dynamics. This will unfortunately lead to a rainy and
windy Halloween, and have categorical PoPs spreading west to east
from early afternoon through the evening. Instability looks limited,
with HREF probabilities of surface based CAPE of at least 200 joules
only 10 to 20% in DESI. The probabilities of 100 joules of CAPE are
slightly better with 30 to 40% seen in the DESI HREF probabilistic
output, but this is a very low CAPE value. This will drastically
limit thunder potential, so only included some slight chances of
thunder. Some "gusty showers" are possible though given the strong
wild fields to tap into. Since the front and associated rain has
trended slower, another day of record highs is expected. Highs
Thursday will reach the upper 70s/low 80s in most areas, except mid
70s in NW Ohio where the rain arrives earlier.
&&
.SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY NIGHT/...
A surface cold front will be pushing through the area Thursday night
as the upper level trough deepens into Ontario/Quebec. The system
will continue to push eastward leaving the region during the day
Friday. The majority of the precipitation will be ahead of the cold
front as it won't move in from the west until around midnight on
Friday. At that time the highest PoPs will be in the eastern half of
the CWA, though showery, there may be some moderate rain falling at
times. Most of the instability will have diminished due to diurnal
effects, but a rumble of thunder can't be ruled out. Winds will
begin to subside as the LLJ moves off east with the trough, though
there will still be the potential for some gusts upwards of 20
mph, particularly within a stronger rain shower.
After frontal passage, most will clear out as high pressure will
start to build in from the west and continue through Saturday night.
There may be some lingering lake effect showers across NWPA and NEOH
with the northwesterly wind, though dry air moves in during the day
on Friday, cutting off the necessary moisture. Much colder air will
move in and temperatures will be close to 20 degrees cooler on
Friday than they were on Thursday, though almost on par with the
normal temperatures. Morning lows on Friday will be in the mid 40s
and highs will be in the mid 50s. Saturday morning will be chiller
with lows in the mid to high 30s. Highs for Saturday will range from
the low 60s out west to the mid 50s out east.
&&
.LONG TERM /SUNDAY THROUGH TUESDAY/...
High pressure will start to build off eastward giving way for a warm
front to push northward during the day Sunday. This will bring
another chance for precipitation periodically from Sunday through
Tuesday. There is still uncertainty regarding the larger scale
features of this system, mainly the strength and position of the
upper level trough and surface low. Continued with 40-60 PoPs during
this time period until there is more agreement and confidence.
Temperatures will be on the rise throughout this period with the
warm front moving through. Highs will be in the 60s Sunday and then
into the 70s for Monday and Tuesday. Lows will jump as well into the
mid to high 50s for the period.
&&
.AVIATION /18Z Wednesday THROUGH Monday/...
Southwest winds of around 10-15 knots with gusts of 20-30 knots
are expected to continue this afternoon. During the overnight
hours, wind gusts decrease, though sustained wind speeds
shouldn't diminish too much. A strong low-level jet overhead
moves in, resulting in low-level wind shear with around 40-45
knots of wind out of the southwest at 2kft. Wind gusts increase
against during the daytime hours on Thursday, with gusts in the
25-35 knot range and perhaps isolated gusts as high as 40 knots
in some spots, especially along and west of I-71. Rain showers
begin to move in from the west early Thursday afternoon.
Outlook...Non-VFR is possible Thursday afternoon and night with
rain showers. Non-VFR also possible with scattered rain showers
Sunday through Monday.
&&
.MARINE...
The Small Craft Advisory remains in effect through Friday due to
strong winds across the nearshore. The southwest winds at
15-20 kts with gusts to 25 kts will continue until Thursday
morning when they strengthen to 20-30 kts. A cold front will move
eastward across Lake Erie Thursday night into Friday and the winds
will strengthen to 25-30 kts and gust to 30-35 kts. There is a small
window for near gale force winds during frontal passage in the
eastern basin. Winds will shift out of the northwest behind the
front and start to subside to less then 15 kts west to east during
the day on Friday. High pressure builds in over the Great Lakes and
the winds will be variable and weaken further to less than 10 kts
Saturday through Sunday. On Sunday a warm front will move south to
north across Lake Erie making the predominant winds be out of the
south and then gradually strengthen to 10-15 kts by Monday.
&&
.CLIMATE...
An anomalously warm air mass will continue across the region
today, with the potential for record high temperatures today and
Thursday.
Daily Record Warm High Temperatures:
Date Toledo Mansfield Cleveland Akron Youngstown Erie
10-30 77(1971) 80(1927) 79(1950) 77(1900) 75(1999) 79(1946)
10-31 80(1950) 78(1950) 82(1950) 79(1950) 78(1933) 76(1927)
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...None.
PA...None.
MARINE...Small Craft Advisory until 10 AM EDT Friday for LEZ142>145.
Small Craft Advisory until 7 PM EDT Friday for LEZ146>149.
&&
$$
SYNOPSIS...Garuckas
NEAR TERM...Garuckas/Saunders
SHORT TERM...Kennedy
LONG TERM...Kennedy
AVIATION...Saunders
MARINE...Kennedy
CLIMATE...
Source:
CLE issues Area Forecast Discussion (AFD) at Oct 30, 1:56 PM EDT---------------
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