Area Forecast Discussion
Issued by NWS Cleveland, OH

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FXUS61 KCLE 200132

Area Forecast Discussion
National Weather Service Cleveland OH
932 PM EDT Mon Mar 19 2018

Low pressure will track east across the Tennessee and lower Ohio
Valleys tonight. The low will split early Tuesday with one
portion moving off the mid atlantic coast Tuesday night. A
second low will remain in the lower Ohio Valley Tuesday night
and then move east and weaken on Wedneday. Thursday high
pressure will build back into the area from the northwest.


No significant changes for the 930 update. Low pressure centered
over TN with ht falls into western VA. The rain shield north of
low just south of the Ohio River.  Current forecast looks

Original discussion...
Models have consolidated on the upcoming storm system and were
fairly close through the near term period. For the overnight
period skies will begin clear to pc but should cloud up
overnight as overrunning moisture spreads north into the area
ahead of low pressure approaching the TN Valley. Brought in
chance pops for far south, mainly Knox and Holmes counties, by
10-12Z Tuesday. Moisture continue to move north into the area
through the morning as the upper low moves into southern OH.
Models show good synoptic forcing moving in with a strong
convergence/divergence pattern across the CWA from MNN to YNG.
Will bring pops to categorical through the morning and early
afternoon across the southeastern half of the area. Will
continue with cat pops south through Tuesday night. The main
problem with this late season event is precip type. With models
showing 850/925mb temps initially above freezing Tuesday
morning precip could begin as a period of freezing rain or zr/s
with any evaporative cooling. As precip moves north surface
temps should rise above freezing through the mid/late morning
into the afternoon however temps aloft will be dropping below
freezing with evaporative and dynamic cooling so expect precip
to transition over to snow through the afternoon. Accums will be
challenged by surface temps above freezing at first. Late
afternoon/evening snow should begin to accumulate with highest
totals likely south/southeast. For now will have around an inch
east of MFD to YNG for Tuesday. Another couple degrees cooler
and accums will be higher. For Tuesday night expect precip to
be snow. At this time have a swath of 2 to 4 inches from MNN to
YNG with lesser amounts north. Storm total at this point 3 to 5
inches with the potential for a couple more depending on temps
and melt. No headlines at this point but need to
monitor/consider during later shifts.


A potent vorticity maximum will move east across the northern Ohio
Valley Tuesday as an upper level low pressure system develops over
the region by Wednesday morning.  The upper level low will move
fairly quickly east by Wednesday morning to the Delmarva and up the
east coast by Wednesday night.  This transition to the coast will
help push the surface low pressure system northeast and away from
the area. Pieces of energy will rotate southeast into the base of an
upper level trough that will setup over the eastern seaboard by
Friday afternoon.  The positive vorticity maximums will bring some
clouds to the area through this forecast period.

But in the mean time, lingering snow on the north side of the
surface low pressure system will begin to quickly pull out of the
forecast area Wednesday morning.  Temperature profiles should
support snow through the end of the event. After that, fair weather
should be the rule Wednesday afternoon through Friday.

As cold air aloft begins to push east, some slight warming of the
air mass will begin to take shape Wednesday through Friday as
surface ridge pushes east to the eastern seaboard by Friday


Forecast challenge as we head into the weekend is the potential for
another precipitation event during the Saturday/Saturday night time
frame. We are watching the interaction between the upper trough to
our east and an area of surface low pressure sliding southeast east
through the Ohio Valley. The ECWMF which had a much stronger surface
low on the 00Z/19 run, has trended towards the GFS with the 12Z/19
run, with a weaker low passing through the lower Ohio Valley. This
would favor more dry air initially in the low levels, with lighter
amounts of precipitation across our area Saturday and Saturday
night. Given that both the Canadian and ECMWF maintain precipitation
across the area, few changes have been made to the forecast. There
remains plenty of time for models to continue to narrow in on
details over the coming days. We did lower or remove pops for Friday
night as all models are at least a little slower. Will continue with
the chance/likely pops on Saturday with a rain/snow mix. Also
lowered temperatures down a degree or two on Saturday given the cool
northeast flow.

Drier air pushes south behind this wave on Sunday and skies may even
try to scatter out given the dry northeast flow. Below normal
temperatures will continue through the extended despite gradual
warming as we head into Monday.


.AVIATION /00Z Tuesday THROUGH Saturday/...
VFR conditions with only cirrus shield to contend with rest of
this evening. Tomorrow Low pressure will track across the Lower
OH valley. Could see a little wintry mix extreme southern
portion of forecast area toward daybreak. Light wintry mix
across the south will transition to rain/snow and then to snow
tomorrow. Do not expect any snow at CLE until toward evening.

.Outlook...Non-VFR Tuesday night through Wednesday most
locations in -sn. Conditions improving from the north and
northwest Wednesday afternoon/evening.


Low pressure will push northeast out of the Oklahoma Panhandle to
the Ohio Valley.  The storm system will interact with high pressure
well to the north.  The two will cause winds to increase out of the
northeast at 25 knots approaching 30 knots at times by Tuesday. Gusts
will reach 35 knots at times as well.  Will continue with the small
craft advisory for the lake until Wednesday morning.  The winds are
expected to diminish Wednesday and expect most of the small craft
advisory to be cancelled at that time.  Otherwise, the winds are
expected to gradually diminish heading into the weekend to light and


MARINE...Small Craft Advisory until 4 PM EDT Wednesday for LEZ144>149.
     Small Craft Advisory until 10 AM EDT Wednesday for LEZ142-143.


SHORT TERM...Lombardy
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