Scientific Forecaster Discussion
fxus61 kcle 221534
Area forecast discussion
National Weather Service Cleveland Ohio
1134 am EDT Sat Jul 22 2017
a stalled frontal boundary will remain in the vicinity, not
pushing out of our area until Sunday. The area will be
vulnerable to showers and thunderstorms that track along and
near the front. A second cold front accompanied by a compact
upper level trough will move across the Great Lakes region
Sunday into Monday. High pressure will finally arrive for Monday
night through the first part of Wednesday.
Near term /through Sunday/...
rain associated with the morning mesoscale convective system continues to exit to the
east. Starting to see some re-intensification across central
Ohio associated with the remnant mesoscale convective vortex. The pool of higher
instability is located south of this axis and that is where the
better potential for thunderstorm activity remains today. A few
of our southeastern counties may still see some locally heavy
rainfall. The Storm Prediction Center has lowered the threat of
severe weather from slight to marginal and certainly agree that
the threat for stronger storms has decreased. Given the moist
airmass heading into the peak heating portion of the day, still
expecting scattered showers and a few thunderstorms to re-
develop, especially across eastern portions of the area. Lowered
high temperatures a few degrees given the cloud cover.
just made tweaks to precip chances through the next several
hours based on latest hi-res short term guidance with this early
morning update. The rest stands. Locations from LaRue through
Marion have received upwards of an inch and half of rain thus
far this morning.
First order of business is dealing with the early morning
convection moving east-southeast out of in and western Ohio. After
that we will have to try and figure out what the afternoon/early
evening might bring and what impact this mornings convection has
on how that evolves.
Most favorable track will keep the bulk of the heavier storms
near and south of Findlay to Mt. Vernon this morning...tracking
along a well defined moisture gradient. A decent portion of the
stratiform rain will extend and track across the rest of
Northern Ohio this morning with embedded thunder. This wave is
moving through fairly early and with decent lower and mid level
flow throughout the day, especially across our southern half of
counties, could see US re-group enough for new convection later
this afternoon and into the early evening. Area remains under
spc's slight risk for severe thunderstorms for any storms that
develop this afternoon. This morning poses more of a heavy rain
threat for Findlay down to Marion as leading convective
appendage may reach these areas and put down a quick inch. If
this occurs and also if this afternoons storms develop in this
same area, concern would turn to a flash flood threat. No plans
yet for a Flash Flood Watch. Otherwise any thunderstorm today
has the potential for locally heavy rain with the amount of
moisture in place.
General trend expected through the evening hours tonight is for
storms to sink southward, lingering longest across our southern
third of counties. Convective allowing models show the late
afternoon/evening development, but differ on placement, central
or southern tier of counties.
The humid conditions will continue with temperatures limited by
substantial cloud cover. Upper 70s well east with debris
cloudiness lingering into the afternoon to mid 80s back toward
Findlay where they will be able to recover.
Linger the highest precip chances across the east for Sunday.
This will likely be more scattered in nature. Again the more
robust storms will have the potential to be strong to severe
with locally damaging wind the primary threat.
Short term /Sunday night through Tuesday night/...
the trough aloft will cross the eastern Great Lakes Sunday night and
Monday. Most of the models are in reasonably good agreement with a
surface trough dropping across the eastern lakes early Monday and
the secondary cold front later in the day or perhaps as late as
Monday evening. Dew points will be dropping and the air mass is not
progged to be all that cold aloft with 850 mb temps progged about
14c and 500 mb temps about -10c so lapse rates should not steepen
too much. Will continue with a small chance of showers and
thunderstorms Monday, mainly east of I-71. Not sure whether Monday
will be partly cloudy or perhaps become mostly cloudy. Will stick
close to guidance temps, generally 75 to 80.
High pressure will slide by on Tuesday with sunshine. Temperatures
and dew points should be a bit below normal.
Long term /Wednesday through Friday/...
the surface high will shift east quickly mid week and the next week
cold front looks as though it may advance across the western and
northern lakes rather quickly on Wednesday. The front seems as
though it may slow as it waits for the next short wave aloft to
deepen the trough aloft. The front may not sag across Lake Erie
until sometime Thursday, perhaps taking until Thursday night to
clear the southern counties. Will continue with a chance of showers
and thunderstorms Wednesday night and Thursday.
If the front is slow enough, Wednesday could be warm. Will forecast
mid 80s but it could be warmer given that 850 mb temps are progged
17-19c. The front should be south of the area by Friday and
temperatures should dip back to a couple of degrees below
normal to close out the work week.
Aviation /12z Saturday through Wednesday/...
complex of thunderstorms has been strongest south of the
terminals early this morning. Stratiform rain shield/embedded
thunder extends north across the terminals with light rain and
some vsby/cig restrictions expected for a few hours this
morning. With rain approaching expecting the IFR at cak to lift
quickly. After this round moves through scattered
shower/thunderstorm chances remain for much of the rest of the
day with the best coverage from fdy to mfd to cak and yng this
afternoon. Trend through the evening will be for activity to
push south. If the storms get robust enough this afternoon, they
may be accompanied by gusty winds. Wind will vary in the
vicinity of the convection, but overall flow will be light south
except up toward eri where they will likely get a east/northeast flow
positioned north of the stationary boundary across northern
OH/PA. MVFR and possible IFR ceilings and/or vsby a concern for
late tonight/early Sunday morning across the area.
Outlook...non- VFR in early morning fog/mist may continue
during the first half of the week.
difficult marine forecast and a tricky weather day as a thunderstorm
complex slides just south of Lake Erie this morning and the
resultant meso low tracks across the lower Great Lakes today. This
will result in moderate south to southwest winds this morning on the
western basin ahead of the meso low, then a shift to the west to
northwest. On the eastern half of the lake, winds may spend much
of the day from the east and northeast. Wind speeds are not expected
to be strong but thunderstorms and local effects could result in
some moderate wind speeds. Not enough for a Small Craft Advisory but
mariners should remain alert for thunderstorms and shifting winds.
High pressure will build across the Great Lakes Sunday and Monday
but it will take a while for the northwest flow to develop on Lake
Erie. A period of northwest to north winds Monday evening into
Tuesday morning may approach Small Craft Advisory conditions.
High pressure will shift east of the lake by Tuesday night and winds
should come around from the southwest by Wednesday ahead of the next