Area Forecast Discussion
Issued by NWS Cleveland, OH

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FXUS61 KCLE 202056
AFDCLE

Area Forecast Discussion
National Weather Service Cleveland OH
456 PM EDT WED JUL 20 2016

.SYNOPSIS...
High pressure over the area will drift east off the coast tonight.
This will allow a warm front to lift northeast across the region
Thursday. A weak cold front will drop into the region Friday night
but will fail to bring any cooling as heat builds east into the
Ohio Valley and Lower Great Lakes through the weekend.

&&

.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
High pressure over the area will slip east overnight. Expecting it
however to continue to dominate the region and should hold any
convection west of the area. Will allow for clear/mostly clear
skies. Lows will be cool east with 50s across nern Ohio and NWRN
PA away from the lake. To the west lows will be in the mid 60s.

&&

.SHORT TERM /6 AM THURSDAY MORNING THROUGH SATURDAY NIGHT/...
Thursday morning high pressure will be centered over PA and should
move to the east coast during the day. At the same time a surface
trough will move from the Northern Plains to the Western Great
Lakes and should extend southwest in to the Central Plains. This
will increase the southwest gradient across the region forcing
much warmer air northeast in to the area over the next several
days. For Thursday 850mb temps increase to 18-19c for the
afternoon and should get to 20c by 00z. The MAV guidance takes
temperatures to the upper 80s most places. feel this is under done
and will go closer to MET numbers in the lower 90s. Heat index
values get to the mid 90s to for now at least no headlines for
the heat. Thursday night low pressure goes through Ontario and
into Quebec dragging a weak cold front onto the lakes. Concern is
that overnight, convection which will likely develop to our
northwest drops southeast into the area. Will have chance pops for
the north after midnight. The models bring this weak boundary into
the area Friday late afternoon/evening so will keep chance pops
for the area Friday ahead of the boundary. Expecting dry
conditions Saturday with whats left of the boundary south of the
region. As for temps, main concern is for Friday and Saturday as
heat builds through the region. Temps at 850mb increase to about
21c Friday and 19 to 21c Saturday. Temps should be able to reach
into the 90-95 degree range. Dewpoints will also be increasing
into the lower/mid 70s raising the heat index to between 100 and
104 across much of northern Ohio Friday. Index values approach 100
west half Saturday with current numbers. However, if convection
hangs around or debris clouds filter the sun we may not make it.
Will not issue any headlines with this forecast but an advisory
for heat may be needed at least on Friday.

&&

.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
Expect the summerlike pattern to persist across the country through
the next week as the strong ridging remains in place across the
southwestern states, with with high heights continuing through the
Ohio Valley and deep south. This will allow the westerlies to remain
displaced well north of the area through the extended with
temperatures above to well above normal for the week.

On Sunday, the GFS and ECMWF are in good agreement in showing the
forecast area in the warm sector in advance of the low pressure
system in the upper Great Lakes. Cannot rule out some showers and
storms especially closer to Lake Erie where the warm front will
be close by. However, the whole area have chances for
thunderstorms due to the very humid airmass (with dew points well
into the lower 70s). May end up seeing another day with heat index
values heat advisory and/or heat warning range with actual temps
topping out in the lower 90s. The better chance for showers and
storms will be Sunday night into Monday as heights lower in
advance of the cold frontal passage on Monday. Behind the cold
front, temperatures will moderate slightly to normal to slightly
above normal, but the humidity should be much less with NW flow.
Will continue with a dry forecast for the Tue-Wed time frame.

&&

.AVIATION /18Z Wednesday THROUGH Monday/...
Very quiet aviation weather through tomorrow at least as high
pressure remains in control. Some high clouds filtering into the
area and some SCT diurnal cumulus are possible this afternoon, but
overall very quiet. A lake breeze should develop today and move
inland with the help of the gradient wind, but the wind should be
less than 10 kt.

OUTLOOK...An area of showers and thunderstorms may move across the
area later Thursday night into Friday. Otherwise...expect
somewhat typical pop up afternoon and evening thunderstorms
through the weekend into early next week.

&&

.MARINE...
Generally quiet weather expected tonight on Lake Erie as the high
shifts east of the area. SW winds will increase ahead of the cold
front starting tomorrow, but wind/waves should stay below small
craft advisory conditions (although it will be choppy Friday into
Friday night across the eastern end of the lake and closer to Erie
with 10-20kt winds). Some strong storms are possible on the lake Thu
night into Fri as a disturbance aloft moves across the area.
Additional storms are possible with a cold frontal passage Sunday
into Sunday night.

&&

.CLE WATCHES/WARNINGS/ADVISORIES...
OH...None.
PA...None.
MARINE...None.

&&

$$
SYNOPSIS...TK
NEAR TERM...TK
SHORT TERM...TK
LONG TERM...99
AVIATION...99
MARINE...99


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