526
fxus61 kcle 181951
afdcle
area forecast discussion
national weather service cleveland oh
351 pm edt wed jun 18 2025
.synopsis...
a cold front will move across the region this evening and
overnight. a strong upper level ridge of high pressure will
build over the ohio valley this weekend into early next week
and bring a heat wave across the region.
&&
.near term /through thursday night/...
3:45 pm update:
key messages:
-scattered showers and thunderstorms ongoing across parts of
northern oh and northwestern pa this afternoon will continue to
be capable of producing locally heavy rain, with an isolated
severe weather risk, before exiting east into this evening.
-after a break, an arcing line of storms is expected to quickly
push in from the west-southwest this evening with greater
potential for severe weather.
-the greatest confidence in severe weather this evening is
across northwest oh, where an enhanced risk (risk level 3/5)
for severe weather is in place. the risk gradually diminishes
east across north central and northeast oh, where a slight risk
(level 2/5) is in place to near the pa border. the risk level
drops off to marginal (1/5) across northwest pa.
-the main severe risk this evening will be damaging wind gusts,
with large hail a secondary risk. there is a lower but non-
zero potential for tornadoes, especially across northwest oh.
-timing into northwest oh (including toledo/findlay) for the
severe threat is greatest 6-9 pm...across north central oh
(including sandusky, mansfield, and lorain) 7-10 pm...in the
cleveland-akron-canton corridor 8-11 pm...in far northeast oh
(including youngstown) 9 pm-12 am...and in northwest pa between
11 pm-2 am if storms remain strong that far east.
an mcv over lake erie is helping to force a batch of scattered
showers and thunderstorms from the lake into northern oh and
northwestern pa early this afternoon. the environment is most
supportive of heavy rain with this initial round, given skinny
instability profiles, high precipitable water values, and rather
marginal amounts of wind shear. with that said, a couple of
cells have been weakly rotating, so will continue to monitor for
isolated/marginal severe potential with the current activity. a
lull in activity is expected behind this activity for a few
hours into this evening, with warm, humid, and somewhat breezy
conditions. hopefully everyone enjoys 70-75f dew points...
after the brief break, the main focus for severe weather arrives
from the west this evening. radar/satellite/water vapor depict
an arcing and strongly-forced band of convection evolving near
the il/in border, with plenty of heating taking place ahead of
the line. the strong forcing and continued destabilization
should allow this line to surge into northwest oh at a strong to
severe intensity this evening. the greatest forcing will pass
just northwest of the region, and timing gradually becomes an
issue farther east as we move towards and past sunset. so, the
greatest and highest-confidence severe threat is across
northwest oh (in and near the spc enhanced risk), with the
threat gradually lowering to the east. however, suspect the line
of storms will have enough momentum to remain strong to at
least locally severe to at least the i-77 corridor (even if
they`re gradually weakening by then), with a lower-confidence
severe threat across the rest of northeast oh and perhaps into
northwest pa. there`s certainly a chance hit-or-miss severe
weather occurs all the way east across our forecast area this
evening into tonight, though will need to assess the state of
the incoming storms this evening and environment across the
local area behind this afternoon`s storms to say with more
confidence how far east an organized severe threat will persist
this evening. with that said, there are enough "pros" that the
spc did expand the slight risk east to the oh/pa border with
their 12:30 pm convective outlook update. activity should exit
oh by midnight, if not slightly earlier, with activity exiting
pa around or just after midnight (see timing in key messages).
in terms of potential severe hazards this evening, the
combination of moderate instability (1500-2500 j/kg of mlcape),
steep low-level lapse rates (0-3km lapse rates of 8-8.5c/km),
marginal to moderate downdraft cape of 700-900 j/kg, and
marginal to moderate shear (effective bulk shear 30-35kt and
0-3km shear of 20-30kt with modest srh) across northwest oh will
support primarily a damaging wind gust risk with a linear storm
mode. if there are any discrete cells, marginally severe hail
is possible...though the primarily linear mode and poor mid-
level lapse rates (near 6c/km) should limit large hail
potential. shear is marginal for a tornado threat, though we
will need to watch for any bowing/surging portions of the line
or any rotating discrete cells that get ingested by the line
for a localized tornado risk. as storms push east this evening,
shear will remain similar to the values listed above or may
increase slightly...while instability and low-level lapse rates
gradually weaken farther east as we move past sunset. this will
likely maintain a primarily wind damage risk with surging/bowing
portions of the line farther east across our area...with lower
but non-zero hail and tornado potential. will also need to
monitor for locally heavy rainfall and flooding with high
precipitable water values remaining in place and some recent
heavy rainfall, though increased flow aloft should keep storms
generally moving this evening and into tonight.
a general lull in activity is expected overnight tonight behind
the round of storms, though with the surface cold front trailing
behind the line of storms there could be some lingering shower
potential overnight tonight. lows will generally dip into the
mid to upper 60s, with somewhat brisk southwest winds continuing
tonight into thursday (gusts potentially 25-35 mph) as low
pressure lifts into the great lakes. the axis of the mid and
level trough will swing through our region on thursday. we will
continue with the chance for scattered rain showers and maybe
some isolated thunder during the day thursday with the higher
pops favoring the late morning through mid-afternoon timeframe.
skinny instability profiles on thursday could support transient
torrential rain-rates with convection, leading to localized
flooding concerns...especially if training impacts saturated
ground. rain chances will taper off from west to east during
the late afternoon and evening as the trough axis begins exiting
to the east- southeast. considerable cloudiness and push of a
slightly cooler, less humid airmass will follow the cold front
passage on thursday with high temps in the mid to upper 70s.
lows thursday night will be on either side of 60 degrees. a
passing shower may push off the lake into northeast oh/northwest
pa thursday night, but most of the area will stay dry.
&&
.short term /friday through saturday night/...
the big focus to end the work week and start the weekend will be the
transition into the first heat wave of summer 2025. a mid/upper
trough will linger over the eastern great lakes and northeast conus
friday while strong subtropical mid/upper ridging amplifies over the
central plains and mississippi valley in response to a closed
mid/upper low swinging into the pacific northwest. northern ohio and
nw pa will remain under the influence of the cooler mid/upper trough
and nw flow aloft friday, although increasing southwesterly low-
level flow and resultant warm air advection will already start to
warm both temperatures and dew points compared to thursday. look for
highs to reach the upper 70s to low 80s areawide, with mid 80s in nw
ohio as dew points rebound back into the mid 60s. lows friday night
will stay in the mid/upper 60s as dew points continue to increase
and hold up low temperatures.
the transition will really take place saturday as the mid/upper
ridge further amplifies, with the center of a sub 595 dm h5 high
shifting northeastward across missouri and southern illinois. a warm
front will be arcing southeast from upper michigan through northern
ohio early in the day on the eastern periphery of the strong thermal
ridging and associated eml, and this warm frontal boundary will
slowly shift east through the day as the aforementioned thermal
ridge drifts eastward. h85 temps will be approaching 25 c in nw ohio
by 00z sunday per the latest nam, and this will easily support
surface temperatures reaching the 90s in nw ohio and upper 80s
elsewhere. stuck with highs in the low 90s in nw ohio at this time
for saturday, but mid 90s are not out of the question if the
aforementioned thermal ridging builds in faster. continued moisture
advection through the day will boost dew points into the upper 60s
to low 70s areawide, and with the wet ground and building eml
(reducing mixing), dew points have a better chance to stay higher
than normal during the day. this will at least raise heat indices
into the 90s areawide.
one wild card for saturday will be a possible mcs, or the remnants
of one, riding southeastward down the warm front and into the lower
great lakes. our location on the eastern periphery of the eml and
associated theta e/instability gradient definitely supports a
complex before the eml and associated strong capping build eastward,
but confidence is low. the environment supports initiation in the
upper midwest and northern great lakes friday night on the nose of a
strong low-level jet, but most early guidance suggests the complex
will outrun the best upper support and instability and weaken as it
dives toward pa and ny saturday morning. there could also be an
outcome where the complex stays stronger and farther west depending
on the strength of the shortwave and location of the gradient. for
now, boosted pops slightly in nw pa late friday night and saturday,
and kept the rest of the area dry, but it will be monitored.
&&
.long term /sunday through wednesday/...
the mid/upper ridge and associated thermal ridging will firmly build
overhead sunday and persist through at least tuesday as the closed
low in the west evolves into a longwave western conus trough and
forces the mid/upper ridge to expand downstream across the entire
central and eastern conus. deterministic and ensemble guidance
remain in strong agreement on this evolution, with the h5 high
strengthening to 595-598 dm and sliding over the ohio valley sunday
and monday, then gradually sinking into the tennessee valley and mid
atlantic tuesday and wednesday. this will support an extended period
of high temperatures in the low to mid 90s, with the wet ground and
strong thermal capping beneath the eml helping to keep dew points
mostly in the 70s (reduced mixing). the worst of the heat will
likely peak sunday through tuesday when h85 temps will hover around
22 to 23 c, solidly supporting mid 90s, but even low 90s look to
linger through wednesday as the ridging gradually flattens and 850
mb temps slowly cool.
the air temperatures will be less important than the consecutive
days of high heat and humidity and resultant heat indices.
probabilities are increasing for heat indices to reach or exceed 100
in many areas sunday through tuesday due to the combination of the
air temperatures and high dew points, with only slight improvement
wednesday. these values occurring for 3 to 4 consecutive days, the
first extended hot spell of the summer, and minimal relief at night
with low temperatures only dipping into the mid 70s will
significantly increase heat-related impacts to human health and
infrastructure. with all of this being said, the new nws heatrisk
product continues to show major impacts by sunday and extreme
impacts by monday and tuesday across all of northern ohio and nw pa.
otherwise, strong capping should prevent any convection sunday and
monday, but have pops gradually increasing for scattered convection
tuesday and wednesday as the ridge gradually flattens and a cold
front slowly sinks down from the nw, but confidence in when a
frontal passage will eventually occur is low at this time.
&&
.aviation /18z wednesday through monday/...
scattered showers and thunderstorms are ongoing from
approximately lpr to mfd points east, with the greatest coverage
over and near lake erie. this activity will continue east while
exiting through late afternoon. lightning, along with brief vsby
reductions to ifr or lower, can accompany storms within this
activity. after a brief lull with breezy south-southwest winds
and mainly vfr conditions, an arcing line of thunderstorms is
expected to surge in from the west this evening. confidence in
impacts is very high (>80%) at tol, fdy, and mfd, high (60-90%)
at cle and cak, and medium (40-60%) at eri and yng. included
tempos at all sites to indicate potential wind gusts, vsby
reduction, and a best guess at a 1-2 hour timing window of
potential direct impacts. this activity exits east, though a
cold front moves through from west to east late tonight into
early thursday. this will bring continued potential for shower
activity along the front, with mvfr ceilings likely spreading in
along and behind the cold front into thursday. another round of
showers and some thunder is likely thursday afternoon, though
future cycles will take a better look at that.
south-southwest winds at 7-15kt with a few gusts to 25kt will
continue through this afternoon and early evening. winds
gradually shift more southwesterly tonight and likely increase a
bit to the 10-18kt range with gusts 20-30kt into thursday.
outlook...non-vfr likely with scattered showers and isolated
storms thursday afternoon. a large high pressure system will
build over the region over the weekend into early next week with
fair skies and quiet weather.
&&
.marine...
a relatively short period of gusty sw winds will occur on lake erie
from west to east tonight and thursday morning as a cold front
approaches and crosses the lake. the sw winds will increase to 15-25
knots first in the western basin around 04z then in the central
basin by 06z and in the eastern basin by 08z, with the strongest
winds lasting about 6 to 10 hours. issued mainly wind driven small
craft advisories for this wind tonight into early thursday afternoon
since the bulk of the 3 to 5 foot wave action will be in the
offshore waters. this should keep the rip current risk moderate in
most areas, with some high risk of rip currents possible in the
eastern basin.
winds will turn nw and decrease to 5-15 knots thursday afternoon
before turning sw at 5-15 knots by friday into saturday. sw winds
will then average 10-15 knots, occasionally up to 20 knots, late
saturday through monday
&&
.climate...
daily record high maximum temperatures
date toledo mansfield cleveland akron youngstown erie
06-22 99(1988) 95(1988) 98(1988) 97(1988) 97(1933) 94(1988)
06-23 96(1911) 91(1964) 94(1948) 94(1923) 94(1943) 92(1964)
06-24 95(2005) 93(1933) 96(1952) 95(1923) 93(1952) 92(1952)
06-25 104(1988) 101(1988) 104(1988) 100(1988) 99(1988) 100(1988)
&&
.cle watches/warnings/advisories...
oh...none.
pa...none.
marine...small craft advisory from midnight tonight to 10 am edt
thursday for lez142>145.
small craft advisory from 2 am to noon edt thursday for lez146.
small craft advisory from 4 am to 2 pm edt thursday for
lez147>149.
&&
$$
synopsis...77
near term...77/sullivan
short term...garuckas
long term...garuckas
aviation...sullivan
marine...garuckas
climate...