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000 
FXUS61 KCLE 240441
AFDCLE

Area Forecast Discussion
National Weather Service Cleveland OH
1141 PM EST Thu Feb 23 2017

.SYNOPSIS...
A weak cold front will settle south into the area this evening
and stall for several hours before turning back north as a warm
front by morning. Low pressure over the central Mississippi 
Valley will track into western lower Michigan by Friday evening.
A trailing strong cold front will sweep east across the area 
Friday night. Much colder high pressure will build over the Ohio
Valley over the weekend.

&&

.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
Update...Made a number of changes tonight through saturday
night from pops and thunder chances to precip type (saturday 
transition).


Original...The weak cold front just to the north of the area 
will settle south into the area this evening and stall. Some 
instability is present with about 500-1000 J/KG of CAPE present 
with little inhibition over the southern half of the CWA. 
Cloudiness is increasing from the west and the radar mosaic 
shows rain spreading east into Indiana with a few light returns 
aloft over nw Ohio. Expect this activity to continue to spread 
east across the area tonight. Some elevated CAPE is expected to 
persist overnight so we will mention the chance of thunder.

The frontal boundary will lift northward toward morning
lessoning the chance of rain so we can expect a decrease in
pops.

&&

.SHORT TERM /6 AM FRIDAY MORNING THROUGH SUNDAY NIGHT/...
A big swing in the weather is expected during this period as we
change from very warm conditions to more seasonal weather with 
dramatic cooling along with the chance of severe weather.

By Friday morning the warm front will have lifted north of the
region taking much of the shower activity with it. That will
leave the region in the warm sector with unseasonably warm and
humid air flowing north across the region. Expect most of the
day to be dry and springlike with readings soaring well into 
the 70s. A capping inversion will be present during much of 
Friday which should limit convection.

By around 23 UTC we expect convection to develop/move into the
western counties from near FDY to TOL. The environment is
favorable for severe weather with CAPE near 1000 J/KG with 
strong deep layer and low level wind shear along with LCL 
heights below 1000M. Damaging winds will be the main threat but 
we cannot rule out a few tornadoes in the TOL to FDY to the Lake
Erie islands region shortly after dark. The threat for severe 
weather will gradually diminish as the activity progresses east 
during the evening. Colder air will sweep into the region after 
the frontal passage.

For Saturday we can expect windy and sharply colder conditions.
Temperatures will be slowly falling with gradually decreasing
chances of rain. We can expect early morning high temperatures
from about 40 to 50.

Cold advection will continue into the overnight with a more
typical low in the 20s. We can expect scattered lake effect snow
showers but the activity will be limited with the inversion
quickly lowering to below 5000 ft. 

Improving conditions are expected Sunday as high pressure builds
into the region.

&&

.LONG TERM /MONDAY THROUGH THURSDAY/...
Temperatures will be in the mid 40s on Monday as a low 
approaching from the west brings southerly winds to the region. 
There are significant differences between the GFS and ECMWF, 
however. The ECMWF is nearly 24 hours slower than the GFS with 
bringing an upper- level shortwave trough and its associated 
weak surface low across the Ohio Valley. The GFS also has a 
stronger shortwave compared to the ECMWF, so it therefore has 
more QPF. The ECMWF has been consistently winning these battles 
this winter, so continued to only go with a chance of 
precipitation for this time frame as the slower solution is more
favored at the moment.

Due in part to the timing differences, the GFS is much cooler on 
Tuesday compared to the ECMWF. Have once again sided with the warmer 
ECMWF, which would bring temps up into the lower 50s Tuesday 
afternoon with a chance of showers.

Both models bring a stronger cold front across the region sometime 
on Wednesday, though they vary considerably with the placement of 
the low. Both models do have a broad upper level trough moving 
across the Midwest during this time frame. It looks like there will 
at least be a chance of showers and perhaps some storms ahead of the 
front, with colder air arriving behind the cold front. We could see 
a few snow showers Wednesday night as temperatures drop below 
freezing and some wrap around moisture works its way into the area. 
Confidence in the long range forecast is quite low at this time, so 
expect changes to the forecast in the coming days as our confidence 
grows.

&&

.AVIATION /06Z Friday THROUGH Tuesday/...
Frontal boundary currently draped from west to east across
northern Ohio and NW PA will lift northward through the first
half of the TAF period. Scattered showers will accompany this
boundary, with potential MVFR ceiling reductions. Best chance
for MVFR will be at KTOL early in the period with the boundary
south of the terminal. Shower chances will diminish after 10Z-
12Z time frame with gradual clearing across the region. Gusty
southerly winds expected, especially from KMFD to KCLE and
westward. Strong cold front will push east through the region 
after 00Z Saturday. Showers and thunderstorms are anticipated, 
possibly impacting western terminals as early as 03Z and KCLE 
after 06Z. 

OUTLOOK...Non-VFR across mainly the snowbelt by later Saturday 
into Sunday. Areas on non-vfr Monday.

&&

.MARINE...
A cold front currently along northern portions of Lake Erie will 
continue to slowly drop across the lake this evening, veering winds 
from SW to N then NE for tonight. Winds will continue to veer around 
to the south by Friday afternoon as the front lifts back north 
across the lake as a warm front. A deep low will move NE across the 
central Great Lakes Friday night, forcing a strong cold front across 
Lake Erie overnight into Saturday morning. Winds will increase to 20 
to 30 knots out of the west on Saturday then gradually diminish late 
Saturday night into Sunday. A Small Craft Advisory will be needed 
for Saturday.

&&

.CLE WATCHES/WARNINGS/ADVISORIES...
OH...None.
PA...None.
MARINE...None.

&&

$$
SYNOPSIS...LaPlante

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