Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Cleveland Ohio
126 PM EDT Wednesday Sep 2 2015
high pressure over the Tennessee Valley will drift east. High
pressure over eastern Canada will build across the northeast
states by Friday.
Near term /until 6 PM this evening/...
mainly tried to track the thunderstorms across northwest and
north central Ohio with the midday update. No other significant
changes. Cumulus elsewhere except along the immediate east
Lakeshore (lake breeze) with a smattering of additional
showers/thunderstorms popping up. Highs mostly in the upper 80s
although locations where the showers and clouds occur during the
early/middle afternoon could hold in the middle 80s.
Short term /6 PM this evening through Saturday night/...
upper level pattern really gets amplified over the next several days
as overall pattern shifts on the West Coast of the lower 48. Deep
digging upper level trough dives into the West Coast over the next
few days causing the upper level ridge in the eastern United States
to amplify. What does this mean for our local area...more high
pressure...warm temperatures...and muggy conditions to produce
scattered showers and thunderstorms through the rest of the work
Once the surface high pressure over the local area becomes absorbed
in the surface high north of Maine...an inverted surface trough will
develop over the local area Saturday into Sunday. Moisture flux from
the Gulf of Mexico will be cut off as the high pressure north of
Maine builds south along the eastern Seaboard. This will limit the
threat for showers and thunderstorms once we get into the early part
of the weekend. Once again...more of the same warm temperatures and
fair weather for Saturday and Saturday night.
Temperatures through the period are going to be very similar each
day. As a matter of fact...I think this is the first I have seen
this but the latest mav guidance says exactly the same min/maximum
temperatures for their respective periods indicating what I have
been saying all along...no change. I dont really see any change in
the air mass through the middle part of next week.
Long term /Sunday through Tuesday/...
not many changes to the long term this morning. The
weekend is still looking warm and humid. There could be a few pop
ups each day but given lack of forcing it is impossible to know when
and where they will occur. Coverage should be under 10 percent so
will keep the dry forecast going. Differences in the models begin
to show up by the end of the period. The European model (ecmwf) remains quicker
bringing a cold front across the area on Tuesday. The GFS doesn't
have this front arriving till Tuesday night. The previous forecast
already had a chance mention for both periods and given the
uncertainty will just continue with that for now. Temperatures both
Sunday and Monday should top out in the upper 80s most areas with
slightly cooler readings on Tuesday.
Aviation /18z Wednesday through Monday/...
much of the same continues today with high pressure in control. A
few pop up rain showers/ts possible but again coverage will be extremely
limited. If there was anything that could hint to a somewhat
better chance of a rain showers/ts such as high res models or current
analysis extrapolated...a vcsh or thunderstorms in the vicinity has been included.
Uncertain if lake breeze will make it through kcle this
afternoon...at least not to take it past 330 degrees.
Tonight into Thursday the pattern shifts ever so slightly and we
will be able to get a very diffuse cold front sink southeastward
across the area in the morning. Have included a middle deck and a few
vcsh with this feature. Ts are possible. Early morning/sunrise
MVFR visibility possible too. Overall the winds which will be west-
southwest for the remainder of this afternoon will come around to
the northwest-north on Thursday behind that front.
Outlook...areas of non VFR each morning in fog and haze. Isolated
thunderstorms may develop each afternoon/evening.
light flow will continue on the lake most of the period.
This will result in onshore flow developing on the nearshore waters
during the afternoon. A back door cold front is still expected to
drop south across the lake Thursday. This will cause the flow to
become east to northeast for a time. Speeds should remain under 15
knots so do not think we will need any headlines. The flow will
return to the south over the weekend. Given the lack of pressure
gradient...speeds most of the time will be under 10 knots.