Area forecast discussion 100 pm edt thu apr 9 2015

fxus61 kcle 091700
afdcle

national weather service cleveland oh

synopsis...
an area of low pressure in the plains will move into the great
lakes tonight. showers and thunderstorms will develop across the
region into friday as a result. a cold front will come through the
area friday...followed by high pressure on saturday.
&&

near term /through tonight/...
update...no big changes for the afternoon.
original...in northeast counties...patchy dense fog will continue
for the next few hours...expected to erode as convection moves
east. second area of convection developing in indiana associated
with the low level jet and an outflow boundary. this feature will
move east into ohio later this morning. convection will refocus
this afternoon when the low level jet intensifies with the
deepening low to our west.with concerns for severe weather...the
best instability will be in the afternoon...however concerned
about the development in indiana and how that may limit the
convection in oh around that same time. it is possible we could
see a respectable break in the convection this afternoon...which
could allow more time for the air mass to destabilize ahead of the
front. any redevelopment tonight will have severe potential with
the synoptic scale boundary moving towards the region. the shear
is impressive and unidirectional. will see storms moving around
45mph to the e/ne...with some downburst/damaging wind potential.
freezing level is around 11k ft...so hail certainly a possibility.
pw values unusually high...coming in around 1.2-1.5"...which is 2
standard deviations above normal for this time of year. this will
support high rainfall rates with any strong cell. the recent rain
has reduced the amount of water the basins can handle before they
flood...so flash flooding and isolated river flooding threat
heightened as well...mainly where storms train. have a flash flood
watch for the southern 1/3rd of counties as these areas have
received the most rain in the last few days and subsequently are
more susceptible to flash flooding. conditions will change little
into the overnight hours so continue with high pops for
thunderstorms.
&&

short term /friday through sunday night/...
the front will push through the area early friday with dissipating
precipitation from west to east. on the increase will be winds as
boundary layer mixing could support wind gusts to 45 mph.
temperatures will fall in the afternoon as the cold air advection
moves in...and dew points will plummet. the surface low will pass
by to the north friday night...with enough support for some light
rain showers...possibly mixed with some snow flakes which will
melt on contact with the ground. high pressure builds in for
saturday with temperatures returning to near normal through
sunday.
&&

long term /monday through wednesday/...
models in good agreement on sunday with high pressure shifting east
of the forecast area and moving off the mid atlantic coast. so
sunday should be warmer and dry. timing of the next system still in
doubt...gfs brings warm front into area with chance of precip monday
night while ecmwf a little slower. for now will just go low chance
pops monday night. both models continue to move the next wave
through on tuesday.
&&

aviation /18z thursday through tuesday/...
rounds of shra/tsra will continue to affect the area into fri
morning until a cold front sweeps across the area to end the threat.
widespread vfr should be the predominate conditions outside of the
convection with areas of mvfr/local ifr in the heavier tsra. south
to ssw winds will increase this afternoon and tonight to be gusting
25 to 35 knots tonight with gusts around 40 knots on fri. the
stronger tsra can easily produce gusts to 50 knots with some large
hail possible.

outlook..some non vfr possible across nrn oh/nw pa late friday and
fri night then just nw pa for early saturday morning. non vfr
possible again for monday.
&&

marine...
east-northeast winds on the lake will veer to the south-southeast
during the afternoon hours as a warm front lifts northward. winds
will then steadily increase ahead of a cold front that is expected
to cross the lake friday morning. a small craft advisory will be
needed for the west of willowick where there is open water late
tonight and through the day friday. not expecting sustained winds to
exceed 30 knots over the stable lake...except possibly for a short
time right with the frontal passage. this will have to be monitored.
winds will diminish friday evening and will be under 15 knots
through saturday. high pressure then move across the lower
lakes/ohio valley over the weekend. a cold front looks to cross the
lake monday morning.
&&

cle watches/warnings/advisories...
oh...flash flood watch through friday morning for ohz029>032-
036>038-047.
pa...none.
marine...none.
&&
$$
synopsis...jamison
near term...jamison/tk
short term...jamison
long term...djb
aviation...adams
marine...djb/oudeman