Scientific Forecaster Discussion
fxus61 kcle 172101
Area forecast discussion
National Weather Service Cleveland Ohio
501 PM EDT Wed Jul 17 2019
the remnants of Barry will move east from Lake Erie to central
Pennsylvania tonight. A warm front will lift northeast across
the area late tonight. A ridge of high pressure will build up
the western slopes of the Appalachian Mountains Thursday and
remain nearly stationary through Saturday. A cold front will
slide southeast across the region Saturday night with a
reinforcing cold front Sunday night. High pressure will build
south toward the area early next week with cooler air.
Near term /through Thursday/...
the remnants of Barry continue to rotate over Lake Erie at this
time and will continue to increase in speed this afternoon and
evening toward the east. The low is expected to move to central
Pennsylvania tonight. Latest radar indicates a significant
increase in convection across the eastern half of the forecast
area as day time heating continues to help destabilize the
atmosphere. There is still a marginal risk for severe
thunderstorms across the eastern half of the area. On top of
that, latest precipitable water plots indicate values just above
2.0 inches across the area. So, rainfall rates in any
convection will be quite high. Good news is that cells are
moving but the bad news is some cells are trying to train
resulting in multiple rounds of heavy rain. So, ponding of water
and rapid rises of small streams and creeks is possible. As the
low pressure system moves east of the area tonight and the sun
GOES down, loss of diurnal heating and instability will aid in
reduction of thunderstorm threat. A warm front is progged to
move northeast of the area late tonight ushering much warmer
air. Winds are expected to become calm to light and there is the
possibility with residual low level moisture that some patchy
dense fog of one quarter mile or less will develop across the
area. Fog and stratus should burn off tomorrow morning for
another fair weather day as a ridge of high pressure begins to
build into the region and pump hot air northeast toward the area
tomorrow and tomorrow night. Expecting lows to drop into the
upper 60s tonight followed by highs in the middle to upper 80s
east to lower 90s west. This will bring apparent temperatures to
between 100 and 103 degrees for heat index. A heat advisory may
be needed in the west. Thursday night's lows will be quite warm
and muggy in the lower 70s east to middle 70s west. This is
only the beginning of a couple day heat wave.
Short term /Thursday night through Saturday night/...
the headline for the end of the week continues to be the heat.
Will still see mid/upper 90s with heat indices topping 100.
Akron to Cleveland and points west still with the best
likelihoodof hitting 105 heat index or greater. Have included
the Youngstown Metro area in the excessive heat watch as well.
The urban area will be close to that 105 mark. All others can
expect to see a heat advisory as we near Friday. Fairly high
confidence in the high temps Friday and Saturday, but mixing and
lowering dewpoints a few degrees will help the apparent
temperatures a touch. Lows will be muggy and warm in the 70s and
provide no real relief.
Precip chances will be very limited Friday with the area largely
capped the further south and west you go under the dome of heat.
Saturday night though a cold front nears and begin to increase
the precip chances.
Long term /Sunday through Wednesday/...
fortunately the heat will only be around for a few days and a
relief will come with a cold front to cross either late Saturday
night or on Sunday. There is still some spread on when it will
cross and therefore effect precip chances, temperatures, and
storm severity. The high in its wake, though, will build across
the region for early next week with temperature returning to
seasonal norms and humidity dropping significantly.
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.
light north winds in the wake of the remnant Barry low, now
southeast of the lake, will continue tonight with light/variable
winds expected Thursday. A warm front will cross the lake
between Thursday and Friday. Southwest winds with an afternoon
onshore component will take place Friday and Saturday. The east
end of the Lake May near Small Craft Advisory conditions each
afternoon. A cold front will cross the lake either late
Saturday night or early Sunday with high pressure following for
early next week.
Ohio...excessive heat watch from Friday afternoon through Saturday
evening for ohz003-006>011-017>023-027>033-036>038-047.