Author Topic: [Alert]CLE issues Area Forecast Discussion (AFD) at Oct 29, 1:20 PM EDT  (Read 116 times)

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CLE issues Area Forecast Discussion (AFD) at Oct 29, 1:20 PM EDT

541 
FXUS61 KCLE 291720
AFDCLE

Area Forecast Discussion
National Weather Service Cleveland OH
120 PM EDT Tue Oct 29 2024

.SYNOPSIS...
A warm front will lift across the region this morning, ushering
in an anomalously warm airmass and gusty winds. A strong cold
front will cross the region late Thursday into Thursday night
followed by high pressure in its wake Friday into the weekend.

&&

.NEAR TERM /THROUGH WEDNESDAY/...
12:30 PM Update...
With this update, the primary change was to increase high
temperatures across the eastern CWA for today as current trends
are warmer than previously forecast. In addition, ended the
chance of precipitation across NW PA a bit earlier as it is now
expected the remainder of the day will be dry. Although
previously mentioned, the fire weather concerns have diminished
quite a bit given the fuel moisture values and RH values
lingering about 45%. If a fire were to start, winds will still
be gusty enough to transport embers.

9:30 AM Update...
Minor adjustments were made to temperatures, but overall the
forecast remains unchanged with this update. Wind gusts have
begun to pick up across the area, with 20 to 30 mph being
reported.

6:30 AM Update...

Increased PoPs to a narrow strip of likely wording that will
progress from north central Ohio into NE Ohio and NW PA over the
next few hours as a warm front lifts through. This narrow area
of showers and embedded thunder is being driven by mid-level
moisture advection and isentropic ascent focused along the warm
front, and it has overcame the low-level dry air to necessitate
the higher PoPs. Otherwise, the forecast remains on track. This
will be quick hitting this morning followed by dry and
unseasonably warm conditions.

Original Discussion...

The well advertised late October warmth starts in earnest today, but
in addition to the record temperatures, there are a few additional
elements of the forecast to discuss.

Early this morning, infrared satellite and water vapor loops show a
pattern that is becoming strongly amplified characterized by a deep
mid/upper longwave trough over the western CONUS and a broad
downstream mid/upper ridge over the central and eastern CONUS.
Shortwave energy ejecting out of the trough is leading to surface
cyclogenesis to the lee of the Rockies while broad surface high
pressure continues to be centered from New England to the Mid
Atlantic. This pattern is already allowing for southerly flow early
this morning, but a warm front currently draped from Lower Michigan
to western Ohio will usher in the truly anomalous warm air. Regional
radar loops show a band of showers and embedded thunder along this
warm front in Lower Michigan, with some developing light showers
farther south into NW and north central Ohio. This is being driven
by mid-level moisture advection and isentropic ascent along the warm
front as a weak mid-level shortwave crests the building ridge. This
area of precip will continue to expand a bit this morning as the
warm front and aforementioned support progress eastward, but
abundant low-level dry air and the bulk of the forcing staying north
of the region will make it tough for any rain to reach the ground
south of lakeshore areas. With this in mind, confined slight chance
to chance PoPs over Lake Erie and adjacent lakeshore areas between
08 and 15Z this morning, expanding slightly over NE Ohio and NW PA
after 12Z based on the trajectory of the forcing. QPF will be very
light, and most areas will not see rain, but kept a little thunder
in the forecast given the weak elevated MUCAPE of 100-300 J/Kg per
HREF guidance. Any rain will be east of the region by early
afternoon as the front lifts out.

Behind the warm front this afternoon, winds will turn more S to SW
and increase to 15-25 knots as a 35-45 knot low-level jet punches
into the region. Mostly sunny skies this afternoon combined with the
strong warm air advection will allow for deep mixing into at least
the 850 mb layer, so this will mix down some of this low-level jet
leading to surface gusts of 35 to 40 mph in NW and north central
Ohio from late morning through the afternoon. While not at advisory
criteria, these winds will certainly have some impact to motorists
driving high profile vehicles as well as blow around unsecured
objects. Farther east in NE Ohio and NW PA, the gusts will be more
in the 25 to 30 mph range due to the best low-level jet being just
to the west and the southwesterly component typically favoring areas
along and west of I-71, but lakeshore areas from Cleveland to Erie
will see some 30 to 35 mph gusts. The gusts will subside as sunset
approaches this evening, but SW winds of 15-20 mph will continue
overnight. These stronger winds and deeper mixing will drop dew
points into the low/mid 50s this afternoon, and this will result in
some lower RH values. At this time, minimum RH values look to dip
into the 40 to 45% range in NW and north central Ohio this afternoon
where mixing will be the strongest, and while this is not at
critical levels, combining it with the gusty winds and drought
conditions could support fire spread, so will mention this in the
HWO.

Otherwise, near record highs are likely today as 850 mb temps warm
to 12-13 C and the well-mixed soundings and dry ground combined with
strong SW winds maximize the warming. Expect highs to reach the
upper 70s/low 80s in NW and north central Ohio, with low/mid 70s in
NE Ohio and NW PA. See climate section for details. Continued warm
air advection tonight will support a very mild night, with lows in
the mid 50s/low 60s. 

Very similar conditions are expected Wednesday. The upstream
mid/upper trough will progress into the Plains and begin to fill as
the northern and southern branches of the jet become separated, but
surface low pressure moving from the Upper Midwest into the northern
Great Lakes will tighten the pressure gradient between the low and
the lingering surface ridge along the East Coast. The low-level jet
in the 850-925 mb layer looks weaker (25-35 knots), but its
continued presence combined with the tighter pressure gradient will
allow for SW winds to gust to 30-40 mph with afternoon mixing once
again in NW and north central Ohio, and 25-30 mph in NE Ohio and NW
PA. These gusty SW winds, warm air advection, and well-mixed
soundings over dry ground will lead to highs in the upper 70s/low
80s areawide, and expect additional records to fall Wednesday. The
good news for those wanting snow is that winter is right around the
corner!

&&

.SHORT TERM /WEDNESDAY NIGHT THROUGH FRIDAY NIGHT/...
An upper level trough continues to push east into the Midwest as a
surface high pressure builds over the Carolinas. The trough will
bring active weather to the region with a surface low pressure and
cold front deeping across the upper Midwest and Great Lakes into
Canada during the day on Thursday. There will be a fairly strong
pressure gradient with the low pressure interacting with the high
off of the Carolinas. Expect winds to be 10-20 mph Wednesday night
into Thursday morning and gusts 20-30 mph, with the higher end of
the winds being in the west counties of the CWA. Clouds and
moisture will increase late Wednesday night with the approaching
cold front. The system has trended slower in the past few model
runs, and have reflected that in the PoPs as the areas in the west
will start to see rain in the morning. PoPs will be high as everyone
will see at least 80 percent chance of rain at some point during the
day on Thursday. No expecting much in the way of thunder with this
system as there is limited instability; it will be mainly gusty rain
showers. Rain chances should diminish around midnight on Thursday
into Friday as the cold front exits the region to the east, making
for a soggy Halloween for Northern Ohio and Northwest Pennsylvania.
Friday will be drier, outside of some lingering lake effect showers
across NWPA, though they will end before midday. Winds will be 10-15
mph and shift out of the northwest making for a much cooler day than
Thursday.

Temperatures on Thursday will still be well above normal, especially
for the eastern half as they will be able to warm up before the cold
front moves through. Most will see temperatures in the mid 70s, and
out east will be in the high 70s which will again threaten record
highs for the day. Overnight lows on Thursday will drop with the
cold front passage and be in the mid 40s across the area. Highs on
Friday will be in the mid 50s.

&&

.LONG TERM /SATURDAY THROUGH MONDAY/...
The weekend will be pleasant and much cooler with high pressure
building in across the great lakes into Sunday. Temperatures on
Saturday will be in the mid 50s before southerly flow returns on
Sunday and pushes high up into the mid 60s. Lows Saturday morning
will be in the mid 30s, with areas along the lakeshore being a bit
warmer in the low 40s. Sunday morning will be warmer with
temperatures in the low 40s across western Ohio and in the high 30s
for the higher elevation areas in the east. The next chance for rain
will be Sunday into Monday as another upper level trough moves
across the plains. There is still disagreement with the models on
the timing of this system, though there will be a wet start to the
week.

&&

.AVIATION /18Z Tuesday THROUGH Sunday/...
Widespread VFR and dry conditions are expected through this TAF
period as the area is positions in the warm sector of a low
pressure system. The only aviation concern during this period is
strong southwesterly winds throughout the period. This
afternoon, southwest winds of 15-25 knots with gusts of 20-30
knots are occurring. The strongest of these winds are being
observed along and west of I-71, primarily impacting KMFD, KTOL,
and KFDY. As the sun sets this evening, the mixing height will
lower and limit the surface gusts to 20 knots or less, but a
strong LLJ of 40-50 knots will then kick in across the area. As
a result, near 03Z tonight, transitioned all terminals to
mentioning LLWS of 35 to 45 knots from the southwest. This
concern will persist into the early morning hours before daytime
heating increases mixing again and the wind gusts of 20-30 knots
return. The strongest gusts will again be seen across the
western terminals.

Outlook...Non-VFR likely Thursday afternoon and night in
showers with a cold frontal passage. Southwest winds will
continue to gust 25-40 knots at times through Thursday.

&&

.MARINE...
The main focus for the marine will be the strong winds through the
mid week into late Thursday. Winds will be south to southwest at 15-
20 kts throughout the week in the nearshore with the open waters
seeing winds 20-25 kts. A Small Craft Advisory has been issued
starting Tuesday at 10AM and lasting most of the week until Friday
at 7PM. The majority of the time, the strong winds will be the main
cause for the advisory until Thursday night with the waves building
to 4-7 ft in the nearshore ahead of and behind the cold front. Winds
will shift out of the northwest on Friday and start to trend down to
10-20 kts. Saturday will bring much calmer winds at 5-10 kts and
waves less than 2 ft as high pressure builds in over the lakes.

&&

.CLIMATE...
An anomalously warm air mass will arrive across the region
today, with the potential for record high temperatures today,
Wednesday, and Thursday.

Daily Record Warm High Temperatures:

Date    Toledo         Mansfield      Cleveland      Akron          Youngstown     Erie           
10-29   78(1999)       79(1922)       78(1946)       77(1900)       75(1999)       75(1946)       
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...Campbell/Garuckas
SHORT TERM...Kennedy
LONG TERM...Kennedy
AVIATION...Campbell
MARINE...Kennedy
CLIMATE...

Source: CLE issues Area Forecast Discussion (AFD) at Oct 29, 1:20 PM EDT

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