Area Forecast Discussion


957 
FXUS61 KCLE 250012
AFDCLE
AREA FORECAST DISCUSSION
National Weather Service Cleveland OH
812 PM EDT Wed Apr 24 2019
.SYNOPSIS...
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.
&&
.MARINE...
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
lake.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...None.
PA...None.
MARINE...None.
&&
$$
SYNOPSIS...Jamison
NEAR TERM...Campbell/Oudeman
SHORT TERM...LaPlante 
LONG TERM...LaPlante 
AVIATION...Campbell/Oudeman 
MARINE...LaPlante