Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Cleveland Ohio
623 am EDT Wednesday Aug 5 2015
a surface trough will dissipate across Northern Ohio today as
high pressure builds into the Great Lakes and Ohio Valley.
Thursday low pressure will move into the lower Ohio Valley as the
high moves east to New England. Friday high pressure will build
back toward Ohio as the low moves to the East Coast.
Near term /through tonight/...
removed the mention of slight chance showers in nwpa this morning.
Previous discussion...high pressure has begun to settle in across
the area. The high will spread drier air into the region from the
northwest with plenty of sunshine in the western two- thirds. There will
be a few more clouds in the east downwind of Lake Erie where highs
will generally be in the low to middle 70s. Out west many locations
will make a run at 80 degree with fewer clouds.
Short term /Thursday through Saturday night/...
high pressure will broaden across the lower Great Lakes Wednesday
night as low pressure moves from the Central Plains to southern
Illinois. The GFS and NAM have shifted precipitation well south of the area on
Thursday...depicting a weaker system...whereas the European model (ecmwf) brings a
hundredth as far north as Mansfield and Findlay. Thinking the
airmass will be much too dry with the high for rain this far
north...so backed off on chance probability of precipitation in the SW for Thursday night.
Friday high pressure builds back in from the north. Afternoon
highs will generally be in the 70s Wednesday and Thursday and closer to 80 on
Friday. Lows will mostly be in the 50s to near 60.
Long term /Sunday through Tuesday/...
northwesterly middle level flow will be over the region on Sunday as
high pressure continues to drift off the New England coast. This
will set the stage for a warm front to lift back into the area. The
warm frontal lift and any ripple of low pressure in the
northwesterly flow will bring the potential for some isolated to low
end scattered coverage of convection. The better chances will be
Sunday afternoon and evening along the lake breeze across NE Ohio
and northwest PA. Chances increase everywhere on Monday into Tuesday as an
upper level trough passes over the region. Current models place the
higher chances of showers and thunderstorms for Monday night into
Highs through the long term will be very close to seasonal averages.
However any convective debris cloudiness Monday into Tuesday may
lower highs slightly.
Aviation /06z Wednesday through Sunday/...
weakening trough/cold front is sagging across Lake Erie and is
approaching the South Shore. Winds will shift around to a light
north or northwest direction in its wake. There may be a few
2500-3500 foot clouds in the wake of the front this morning. At
this point it appears it may be dry enough to keep it from
becoming a ceiling. These clouds will decrease in coverage as high
pressure takes control for the afternoon. Winds off of Lake Erie
will be a bit stronger and could be over 12 knots. This will
mainly impact Keri and kcle.
Outlook...non VFR patchy morning fog will be possible Thursday
through Sunday. Non VFR conditions may also be possible in
isolated thunderstorms Saturday afternoon into Sunday across the
high pressure will build across the lake today. This will provide a
northwest to north flow across the lake. As the high weakens and is
nudged eastward on Thursday winds will shift to the northeast. This
longer fetch into the western half of the lake will cause waves to
build. We will need to monitor for a possible Small Craft Advisory
from Avon Point westward for Thursday afternoon and evening. If the
pressure gradient ends up being tighter than anticipated as low
pressure passes to the south of the Ohio River we will need to nudge
wind speeds up. Since water levels are so high we may also have to
watch for the potential of pushing this water further onto land.
Stay tuned for later forecasts on the track of the low Thursday into
High pressure will then ridge across the area from Ontario and
Quebec Friday night into Saturday. There will be a lake breeze each
day of the weekend with the weak pressure gradient across the