Area Forecast Discussion
Issued by NWS Cleveland, OH
FXUS61 KCLE 200604
Area Forecast Discussion
National Weather Service Cleveland OH
204 AM EDT Thu Oct 20 2016
Low pressure will track across SE Ohio Thursday afternoon and reach
central Pennsylvania Thursday night. Much colder air will spill
across the forecast area in the wake of the storm system setting
up lake effect showers in the snowbelt into Saturday.
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
Convection continues to develop close to the warm frontal boundary
at this time and it appears most of the lightning remains south.
As the storm system moves northeast along this front, it will
become nearly stationary southwest to northeast across the
forecast area. I mentioned isolated thunderstorms across the
southeast half of the area due to the proximity of the front. The
other issue at hand is the cold air advection pushing south across
the northern tier counties. I think this cold air intrusion will
slow down and allow for some warming or temperatures holding
nearly steady across the north central and northeast. Cold air
advection will continue at Toledo and the northwest. In the
southeast, temperatures should begin to warm up overnight into
tomorrow morning as the warmer air lifts north. So, made
adjustments to temperatures accordingly overnight.
.SHORT TERM /6 AM THIS MORNING THROUGH SATURDAY NIGHT/...
The short term is wet and much colder. Models a little further
north with the track of the low than yesterday. Models track the
low across SERN Ohio tomorrow morning...to near Pittsburgh by
early afternoon. A surge of moisture ahead of the low will help
feed the showers. expect convection north of the low as it tracks
across Ohio...but there is still some doubt as to how far north
the convection will reach. Continued with isolated tsra south of a
Marion to Warren line. The low tracks into Central Pa by Thursday
evening. However...showers in the East will continue to be fed
Thursday night into Friday by lift from a 120 knot jet at 300mb
that will track across the Eastern Great Lakes. At this time still
looking like a widespread 1-2 inches across the forecast area for
the event...with the heavier amounts in the east.
Much colder air will spill across the forecast area behind the storm
system setting up lake effect showers across the snowbelt. The
850mb temps will dip to 2 to 3c by daybreak Friday...and plunge to
-2 to -3c Saturday. With a lake to 850mb differential reaching 20c
and plenty of low level moisture expect Lake effect showers across
the snowbelt Friday night into Saturday. Potential for a little
snow along the ridges Saturday morning...but for now will not
mention the s word. Expect the coldest temps of the season thus
far with highs Saturday in the upper 40s to lower 50s.
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
The long term begins on Sunday with the models showing a broad upper
ridge across the nation`s mid section and a closed upper low over
Maine/Quebec region. At the surface, high pressure will be extending
into Ohio from the south. The GFS tries to develop a short wave and
drop it southeast across the Great Lakes Sunday night into Monday
but the ECMWF is not as strong with the feature. Even so...models
also keep most of the impact north and east of the area so will
largely ignore. There will however be a cold front that drops across
the region likely on Monday but again, impact outside of NERN OH and
NWRN PA should be minimal with potential precip mainly in the lake
effect areas with the cold air across the lake. Dry air and high
pressure build in from the NW Monday night and early Tuesday.
Return flow Tuesday night into Wednesday could bring a few showers
back to the region but much of the impact appears to be confined to
areas north and west of the region. Rain chances improve Wednesday
night into Thursday as more moisture out of the GLFMX moves
into the area. Highs within a few degrees of normal each day.
.AVIATION /06Z Thursday THROUGH Monday/...
Conditions will deteriorate as low pressure moves northeast along
a front across the upper Ohio Valley over the next 24 hours. Rain
will overspread much of the area before dawn after which a lull
of several hours is possible. There may be a few rumbles of
thunder toward MFD/CAK with this early round. Showers across the
area and possibly more thunderstorms /MFD CAK YNG/ bubble up
later this afternoon. A steadier rain returns as the wind shifts
and the colder air arrives toward evening. IFR possible in any of
the heavier showers and any TS. A swath of IFR ceilings most
likely along and just north of the front which will become more
defined with time. Conditions more variable south of this front.
Unsure how far north to take the widespread IFR cigs...and made an
adjustment to TOL...keeping them MVFR. Wind on the north/cold side
of the front pick up to 10 to 15 knots and continue that way into
tonight. We may see some gusts to 25 knots.
OUTLOOK...Non-VFR continuing through Friday morning...lifting
across the west Friday afternoon. Northeast OH/northwest PA will
have Non VFR possible through Sunday morning.
Low pressure will move into the Lower Ohio Valley tonight and early
Thursday and then reach Central PA during the afternoon. Light
winds this evening will turn northeast overnight and increase to 10
to 15 knots by morning. Winds will back to almost North during the
afternoon increasing to 15 to 25 knots. A small craft advisory will
likely be needed by mid/late afternoon. Winds will continue to back
slowly to northwest by Friday and continue at 15 to 25 knots through
at least Saturday night as the deepening low moves east and high
pressure builds in from the west. Sunday expect winds to back to
west and diminish to 10 to 15 knots as high pressure extends onto
the lake from the south.