Area Forecast Discussion
Issued by NWS Cleveland, OH

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FXUS61 KCLE 171738
AFDCLE

Area Forecast Discussion
National Weather Service Cleveland OH
138 PM EDT Wed Jul 17 2019

.SYNOPSIS...
The weakening remnant low of Barry will move northeast near
Lake Erie this afternoon. In its wake a ridge of high pressure
will build north into the region by Thursday morning, then
remain nearly stationary over the eastern United States through
Saturday.

&&

.NEAR TERM /THROUGH THURSDAY/...
Latest satellite trends showing some breaks in the overcast over
the western portions of the forecast area. This should help
boost temperatures this afternoon. Dewpoints have risen into the
middle lower to middle 70s across the area. Showers are
becoming more active in the east and this should increase
chances for precipitation this afternoon. So made some
adjustments to temperatures and weather/pops across the area for
the afternoon hours along with the cloud cover.

Previous Discussion...
The weakening remnant low of Barry will move near Lake Erie
this afternoon. The warm front that is currently lifting
northward across the area is producing a decent sized area of
showers and thunderstorms. Fortunately the convection is moving
along at a decent clip which is limiting the the rainfall
amounts. Still may see a quarter to half an inch through the
morning at several locations. We then monitor the region for
additional thunderstorm development through the afternoon as the
weak front associated with the low sweeps west to east across
the region. It does not appear that there will be widespread
severe weather today but cant rule out a couple wet microbursts
across the eastern portion of the County Warning Area.

Models are also hinting at a heavier swath of rainfall from NE
Ohio into NW PA. Dont want to issue a flood watch at this point
in time but we will need to monitor this closely. If storms
begin to train across this region a short time period flood
watch may be needed.

In the wake of the low we will see high pressure ridge into the
region from the south. It should reach into the region by
Thursday morning. This will allow the region to warm
significantly. We will need to monitor the western CWA for a
heat advisory Thursday afternoon.

Highs today should range from the upper 70s east to upper 80s
west. Warmer on Thursday with 80s to lower 90s anticipated.

&&

.SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY NIGHT/...
The big weather story for the end of the week will be a dangerous
heat wave building across the Ohio River Valley region. Upper level
heights will be rising as an upper level ridge will be expanding over
the region. Rain changes will be very slim to none under the dome of
hot airmass. Guidance indicates that Friday will likely by the
hottest day so far this Summer season with afternoon high
temperatures climbing into the middle to upper 90s. Dewpoints will
be in the lower to middle 70s which will result in very humid
conditions and dangerous heat indices. We will have to watch and see
if we get any mixing of drier air off the surface that may result in
slightly lower dewpoints and heat indices. The heat index on Friday
afternoon will range from 100 to 110 across the area with the
hottest west of I-71. This area is generally where the Excessive
Heat Watch has been issued Friday and Saturday. Southwesterly winds
will be breezy between 10 and 15 mph.

Upper level heights don`t change much on Saturday. There may be a
little more high cloudiness from convection developing across the
Upper Great Lakes region. This scattered high cloudiness may help
air temperatures be just a couple degrees cooler with highs still in
the lower to middle 90s with heat indices between 100 to 110 again
Saturday afternoon. A slow moving cold will be just to our north
across the Upper Great Lakes region where most likely showers and
storms will be. Can`t rule a few stray pop up storms given the heat
and humidity but very slim rain chances for Saturday. The slow
moving frontal boundary gets closer to Lake Erie by Saturday night
and scattered rain chances start to increase a little bit.

&&

.LONG TERM /SUNDAY THROUGH TUESDAY/...
The weather pattern shifts in a big way for the late part of the
weekend into early next week. A trough will dig down across the
Great Lakes as a very large upper level ridge expands over the
western U.S. A cold front will slowly move through the region on
Sunday and bring better chances for scattered showers and storms
along with mostly cloudy skies. A few strong to severe storms could
be possible Sunday afternoon and evening along the cold front. Air
temperatures will decrease as well with highs only in the middle
80s. There are some minor differences in the structure and strength
of the trough between the 00z GFS and 00z EURO but overall in fair
agreement. A 1027mb Canadian surface high pressure will be building
down across the region Monday through Tuesday with a drier and
cooler airmass. Temperatures will be cooler than average early next
week with afternoon highs in the upper 70s to lower 80s and
overnight temperatures down in the upper 50s and lower 60s.

&&

.AVIATION /18Z Wednesday THROUGH Monday/...
Circulation around the remnants of Barry are now over Lake Erie
and convection is becoming more active across the eastern half
of the forecast area. Meanwhile, across the western half of the
area, clouds are scattering out allowing for ample sunshine.
Will mention potential for heavy rain over the eastern half of
the forecast area this afternoon and early evening with
remaining convection. This will also move out of the area this
evening. As residual moisture lingers, possibility for some
dense fog tonight across the area. Expecting visibilities to
possibly drop to around 1/4 mile or less til sunrise. Then,
going VFR tomorrow morning.

OUTLOOK...Non-VFR possible in showers and thunderstorms
Saturday night into Monday.

&&

.MARINE...
The remnant low pressure of Barry will move across the lake today.
Winds will be generally light and shifting from southerly winds 5 to
10 knots to northerly briefly this afternoon. Weak surface high
pressure moves in overnight with light and variable winds. High
pressure to the south and low pressure across the Upper Great Lakes
will develop a pressure gradient over the lake Thursday through
Saturday. Southwest winds will generally be 10 to 20 knots with
stronger winds during the afternoon. We may get closer to Small
Craft Advisory conditions Friday afternoon. A cold front will move
across the lake late Saturday night and Sunday. Winds will shift
behind the front to northerly 10 knots late Sunday. High pressure
builds in from the north Monday into Tuesday with northerly winds 10
to 20 knots.  We may get close again to advisory Monday afternoon
for winds and higher waves near the lakeshore.

&&

.CLE WATCHES/WARNINGS/ADVISORIES...
OH...Excessive Heat Watch from Friday afternoon through Saturday
     evening for OHZ003-006>011-017>021-027>032-036>038-047.
PA...None.
MARINE...None.

&&

$$
SYNOPSIS...MM
NEAR TERM...Lombardy/MM
SHORT TERM...Griffin
LONG TERM...Griffin
AVIATION...Lombardy
MARINE...Griffin


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