FXUS61 KCLE 250012
AREA FORECAST DISCUSSION
National Weather Service Cleveland OH
812 PM EDT Wed Apr 24 2019
High pressure over the region will drift east tonight making way
for a warm front to lift north. An upper level trough will
deepen on Thursday and a surface low will eject north from the
Mississippi Valley passing through Ohio Thursday Night. High
pressure will build in its wake for Friday into Saturday. A
northern stream shortwave will move across the northern plains
and across the lower lakes on Saturday night bringing more rain
to the area.
.NEAR TERM /THROUGH THURSDAY NIGHT/...
No changes with this early evening update. Previous discussion
follows. Apart from thin cirrus skies were mostly clear across
the region. The dry airmass in place (PW~0.25") will drift east
tonight supporting return flow. The moisture advection and
clouds will keep temperatures from bottoming out for all but
perhaps NW PA where lows could reach the upper 30s as the high
pressure lingers longer. The air mass moistens up to 0.75" to
near an inch by morning, highest south of the US 30 corridor.
Saturating of the air column will take time and slow down the
onset time of the rain to near daybreak. Keeping a tight
gradient on the POPs for Thursday as the best forcing and
moisture should be across the southern counties, so allowed for
some likely PoPs there. The position of the warm front will
determine the extent/coverage of the rain shield for the first
half of Thursday. By Thursday afternoon the deepening wave lifts
into Ohio driving the warm front to the lake. Showers activity
will increase notably by Thursday night as the low lifts through
the area. Ahead of the low there could be enough elevated
cape/slight instability to support limited thunderstorms, again
mainly in the warm sector along the front (US 30 corridor)
during the afternoon.
.SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
Another cool weekend with a chance of showers is expected with a
rather fast changeable pattern. A surface low pressure area will be
moving through and out of the area Friday morning with a rapid
decrease in POPs and afternoon clearing. High pressure will build
over the region Friday night and early Saturday. Scattered frost is
likely inland of Lake Erie in low-lying spots. The high pressure
will quickly exit the area Saturday afternoon as a short wave and
associated surface low pressure clipper from the upper Mississippi
Valley approaches the region. The clipper will track just south of
Lake Erie late Saturday night and spread showers into mainly the
northern half of the region.
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
Low pressure over the region early Sunday morning will quickly move
east to the east coast by evening. Precipitation and clouds will
quickly decrease through the day. High pressure will build over the
region Sunday night and there is another chance for frost away from
the lake especially in low lying areas. The high pressure will shift
east into New England for Monday and Tuesday as a warm front
develops over the lower Ohio Valley. The location and evolution of
the warm front is rather uncertain as model solution divergence
increases through the period. The ECMWF is slower in moving the
feature into the region with its attendant precipitation. The GFS is
faster and much wetter. For now there is a chance of showers Monday
afternoon into Wednesday. Temperatures will be running a few to
several degrees below normal.
.AVIATION /00Z Thursday THROUGH Monday/...
VFR conditions will continue for the first 12 hours of the TAF
period for all terminals. High clouds have begun to stream in
over the area from the south. These clouds are expected to
gradually lower beginning Thursday morning as the mid level
become more saturated. Rain showers could begin as early as
06-09Z in FDY/MFD. Rain showers will not reach other TAF sites
until Thursday afternoon. A transition to MVFR conditions will
occur after 12Z. Rain intensity will increase and expand
northeast Thursday evening as low pressure moves through the
area which will support widespread MVFR conditions with a
potential of IFR conditions in stronger bands. Winds will remain
light and variable as the low continues to move north.
OUTLOOK...Non-VFR possible Thursday night and early Friday
morning, and again on Saturday Night.
A tranquil night is expected over Lake Erie. High pressure over
the area will shift to New England by Thursday morning. Light
southeast winds can be expected. The high pressure will move off
the New England coast on Thursday afternoon as low pressure
over Mississippi Valley moves into the Ohio Valley. The low
pressure will track into Ohio Thursday night and into western
New York Friday morning. Northwest winds will increase behind
the low pressure on Friday but should remain below SCA. High
pressure will build over the lake late Friday night and early
Saturday and winds will subside. A clipper system will track
near the lake late Saturday night and east of the area on
Sunday. Northwest winds will increase behind the low and a SCA
may be needed for Sunday afternoon. Tranquil weather will
prevail over the lake on Monday as high pressure builds over the