Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Cleveland Ohio
944 am EDT Friday Aug 1 2014
a weak ridge of high pressure will build over the lower Great
Lakes today. An upper level disturbance will move up the Ohio
Valley tonight and Saturday and then shift to the East Coast on
Sunday. High pressure will return to the region for the beginning
of the new work week.
Near term /until 6 PM this evening/...
update...no big changes for the update.
Original...a fairly quiet day is in store for the local area.
Skies are currently clear to partly cloudy and should remain that
way today. For a change there are no returns on the radar. Most of
the area will be dry today but will continue with a small chance
of storms in Northwest Ohio this afternoon. That area could see a few
showers/storms develop as a piece of energy moves through the
upper trough. Instability will again be lacking so nothing more
than brief downpours are expected with any storms that develop.
Temperatures will get off to a warmer start than yesterday and 850 mb
temperatures are also supposed to be a tad warmer today. This should
result in high temperatures a couple degrees warmer than Thursday with
most locations topping out in the low 80s.
Short term /6 PM this evening through Monday night/...
precipitation chances will increase tonight as moisture converges over
the area from the northwest and southeast. An inverted trough will
slide across the area on Saturday and best chances for rain during
the period will occur then. Some of the guidance is suggesting
that likely probability of precipitation are needed for Saturday but think the coverage
will be more scattered in coverage and will stick with no more
than a 50 chance. Things will dry out from west to east late
Saturday and by late Saturday evening most if not the entire area
will be dry. The system along the East Coast could bring some
lingering precipitation to the far east on Sunday but again most of the
area will be dry. Although there will be a slight increase in low
level moisture over the weekend...instability and shear will be
lacking so nothing more than a few strong storms are expected.
High pressure will return late Sunday and linger over the region
through the end of the period. Temperatures will remain a little below
normal through the weekend.
Long term /Tuesday through Thursday/...
long range models are showing the next front dropping south across
the area sometime on Tuesday. Significant differences remain beyond
that time with the 00z European model (ecmwf) and Gem trending towards a deeper
trough setting up over New England which would tend to push the
front/moisture axis pretty far to the south for Wednesday/Thursday.
Meanwhile the GFS has the front stalling over Northern Ohio which would
maintain a more active pattern through the middle-week time frame.
Although not consistent with earlier runs...would tend to lean
towards the deeper trough as this has been the dominant pattern over
the last several weeks. Will carry low chance probability of precipitation for most periods
given the uncertainty but if the front pushes far enough south with
high pressure building over the central Great Lakes then we might be
able to remove probability of precipitation for a few periods. Temperatures remain near 80
in Northwest Ohio/middle 70s for NE Ohio and northwest PA.
Aviation /12z Friday through Tuesday/...
patchy ground fog with MVFR visibilities will clear most areas by
13z...giving way to VFR conditions. A scattered-broken cumulus deck will develop
this afternoon with a low chance of showers/thunderstorms...mainly in
Northwest Ohio after 21z as the next upper trough approaches from the
west. Chances of precipitation are in the 20-30 percent range and
only included vcsh at tol/fdy this afternoon. Moisture increases
in NE Ohio overnight leading to br at mfd/cak/yng. Kept the
forecast conservative but could see visby drop to IFR as dewpoints
Outlook...non VFR during scattered showers/thunderstorms Friday
night through Sunday...especially on Saturday. Non VFR possible
again by Tuesday.
Lake breezes expected today with waves 2 feet or less. Light
northerly winds will develop over the weekend as a weak surface
trough nudges north into the Ohio Valley. Generally good marine
conditions through the weekend except for scattered thunderstorms.
Southwesterly flow will return on Monday ahead of the next front
pushing down from the north.