Cleveland NWS Area Forecast Discussion - 15Jun2013 - 1758

area forecast discussion
national weather service cleveland oh
558 pm edt sat jun 15 2013

.synopsis...
a ridge of high pressure over pennsylvania will move southeast
off the carolina coast tonight. low pressure will develop and move
across the central great lakes on sunday and drag a weak frontal
boundary across the region. another low over central canada will
drop across the central great lakes monday and push a stronger
cold front across the region. high pressure will build in by the
middle of the week.

&&

.near term /until 6 am sunday morning/...
the lead short wave will cross the area this evening. much of the
upward motion will be spent just moistening up the air mass. the
showers are light...mostly sprinkles... but have made better
progress than the mid afternoon forecast. will allow for a
chance/slight chance of showers just about everywhere this evening
but again...it will be little more than a sprinkle for a lot of
the area. still think the better rain threat comes after
midnight...probably not until the predawn hours.

strong lift helped in part by favorable upper level jet dynamics
should cause an area of showers to develop. have bumped precip
chances up slightly to near categorical in the east by daybreak.
lapse rates are not all that steep but given decent dynamics think
that some embedded thunder is a good bet. dewpoints should rise to
around 60 degrees later tonight which is where lows will be.

&&

.short term /6 am sunday morning through tuesday night/...
an active pattern will persist. there should be a lot of shower
and thunderstorm activity across the area on sunday as a weak
boundary moves across the area. li/s will dip below zero with
capes of 1000 j/kg or more ahead of the front. this means thunder
chances should be better than tonight. things are forecast to dry
out behind the boundary late tomorrow. sunday night could end up
being mainly dry but precip chances will again begin to increase
early monday. 

h2. Monday Storms?

q.
low pressure is still progged to drop into the
region and drag a cold front across the area on monday evening and
night. temps will likely get into the 80s with low to mid 60
dewpoints ahead of this feature. we could end up seeing some
strong storms. right now think coverage will be scattered in
nature and will hang on to chance pops. 
q..

things will then dry out
quickly early tuesday and will go with dry weather for the
remainder of the period as high pressure builds in. temps sunday
and monday will be within a few degrees of normal but a distinct
air mass change will occur behind the cold front monday night.
highs tuesday will struggle to get out of the low 70s most areas.

&&

.long term /wednesday through saturday/...
by mid-week the upper level trough axis will have shifted to the
east coast while a ridge builds over the plains. this will leave
the forecast area under the influence of cool and dry northwest
flow aloft with high pressure and stable conditions building from
the central great lakes to the east coast wednesday into thursday.
with northerly flow off the lake...highs on wednesday will be
slightly below normal in the low 70s...recovering 3 to 5 degrees
for thursday.

warm advection gets underway on friday as the ridge expands eastward
with increasing southerly flow. long range models in agreement in
showing shortwave energy rounding the ridge with moisture starting
to sneak back in for saturday. have added a low chance of showers
and thunderstorms to the forecast. will keep highs conservative in
the low to mid 80s given uncertainty in timing/coverage of precip
but these may need to be raised.

&&

.aviation /22z saturday through thursday/...
clouds and showers approaching from the west across indiana will
approach tol/fdy by 22z although showers are expected to become more
scattered as they continue eastward into the drier air. the next
round of showers and thunderstorms developing back to the west
across illinois/iowa are expected to move across northern ohio
with support from a weak low level jet during the overnight hours.
some uncertainty exists in the trajectory of the next round but
confidence was high enough to introduce a tempo with thunderstorms
between 02-07z at tol/fdy/mfd. will wait to add more than a vcts
to the other sites until timing and evolution becomes a little
more clear. expecting vfr to continue until any heavier showers
arrive tonight with mvfr ceilings possible behind the rain late
tonight. southerly winds will shift to the west behind the complex
on sunday.

.outlook...non vfr possible tonight through monday in showers and
thunderstorms. non vfr ceilings may linger into tuesday.

&&

.marine...
light southwest winds on the lake will increase to 10-15 knots
tonight before veering to more westerly on sunday as a weak area of
low pressure passes to the north. this will also be accompanied by
an area of showers and scattered thunderstorms moving east across
the lake into sunday morning.

a back door cold front will push south across the lake on tuesday
with winds shifting to the north. this will be followed by light
winds and good marine conditions through thursday.

&&

.cle watches/warnings/advisories...
oh...none.
pa...none.
marine...none.

&&

$$
synopsis...kosarik/kubina
near term...kosarik/kubina
short term...kubina
long term...kec
aviation...kec
marine...kec

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