Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Cleveland Ohio
427 am EDT Friday may 29 2015
high pressure will move off the New England coast today allowing a
cold front to move into the central Great Lakes this evening.
This cold front should sweep across the region Saturday. Cool
Canadian high pressure will try to build in from the north on
Near term /until 6 PM this evening/...
southerly winds will bring an increase in low level moisture back
to the region today. Already seeing a few showers moving into
southwest Ohio. This seems to be where the better moisture
advection is occurring. This area of moisture and lift should
continue northward through the morning with some scattered
showers possible. As we heat up through the morning into the
afternoon the coverage of the showers and thunder is expected to
increase. At this point will not go more than scattered coverage
but later shifts will need to monitor closely.
It will be warmer today with highs back into the lower to middle 80s.
Short term /6 PM this evening through Monday night/...
the late afternoon showers will drift slowly northward through the
evening and should exit the County Warning Area after midnight.
We will then wait for the cold front and better lift to arrive
Saturday. At this point it looks like the showers and thunder will
ramp up through the morning with all locations getting at least
one round of rain by middle afternoon. The severe threat is a
difficult call. Cloud cover should limit the heating some as the
main jet energy remains over Ontario and Quebec. However there is
a 30 to 40 knot low level jet that may be enough to initiate some
stronger convection late morning into early afternoon ahead of the
main line of showers and thunderstorms. Will still mention severe
in the severe weather potential statement but confidence in its occurrence has decreased
The main cold front will take its time to cross the County
Warning Area with showers likely lingering into Sunday morning.
All of the showers should be east of the region by Sunday evening
with cooler and drier air anticipated. Skies will clear Sunday
night with lows dipping into the 40s at most locations. Sunday
will be the cool day of the weekend with cloud cover and lingering
showers holding highs in the 60s...maybe only upper 50s across northwest
PA. Warmer on Monday with sunshine. Highs will rebound to the
upper 60s and lower 70s.
Long term /Tuesday through Thursday/...
the models are now showing the cutoff upper low staying over the
Gulf Coast while upper ridging builds over Ohio. Will carry only
minimal probability of precipitation for widely scattered convection for mainly the afternoon
and evening. Temperatures should show a warming trend with above normal
readings for Wednesday and Thursday.
Aviation /06z Friday through Tuesday/...
winds turning southeast then south through today will bring increasing
moisture back into the area. Patchy fog may occur here and there
until 13z. A threat for rain showers/thunderstorms and rain will be increasing during the
day into evening as a warm front lifts across the area. Scattered thunderstorms and rain
will likely hang around tonight as the airmass remains unstable
ahead of an approaching cold front. As far as thunderstorms and rain at any given
taf site...will use thunderstorms in the vicinity for now then when the threat becomes more
definite then more emphasis can be places on timing.
Outlook...non VFR conditions Saturday in shra/ts. Non VFR possible
south winds should gradually increase to 10 to 20 knots ahead of
a cold front that will cross the lake later on Sat. Winds turn
north Sat evening then NE later Sat night and look to increase to 15
to 25 knots with waves building to about 4 to 6 feet so a Small Craft Advisory will
be needed for this time. Winds and waves slowly subside Sun night
into Tuesday while remaining east.