Scientific Forecaster Discussion
fxus61 kcle 251712
Area forecast discussion
National Weather Service Cleveland Ohio
1212 PM EST Sat Feb 25 2017
a cold front over the east will continue off to the east this
morning while a reinforcing cold front drops southeast across the
area later today. High pressure will push northeast over the region
for Sunday and Monday then shift off to the east for Tuesday. A low
will move northeast from the plains Tuesday across the lower lakes
Wednesday pulling a cold front through the area.
Near term /through tonight/...
not much showing up on radar with a few showers at the far east
and west ends of the area. Area of clearing continues to move
across the area but will fill in shortly leaving skies mainly
cloudy. Expect lake effect activity to get going later this
afternoon east of kcle. Elsewhere...precip will be negligible
and have lowered chances most areas. Have adjusted temps
slightly as well.
Previous...the cold front producing the threat for tsra pushing
east of the cwa at this time so threat for tsra appears to be
done. Band of shra with the front will still take another 3 to 4
hours to shift east of the area.
Wrap moisture aided by an upper trough crossing the cwa will keep a
lingering threat for shra today that will shift into just the
snowbelt by nightfall. Temps aloft and at the surface should get
cold enough to start to support frozen precip from late morning on
in a west to east pattern of change. Due to the warm ground temps
and ending of precip most places, little or no accumulation is
expected. Temps will fall all day, into the low to mid 30s by
evening. Winds will gust 30 to 40 mph at times.
Short term /Sunday through Monday night/...
marginal lake effect conditions will be in place tonight but will
become less favorable by the end of the night as high pressure
builds NE into the snowbelt. The shsn should be done by Sun
afternoon leaving one to locally 3 or 4 inches of accumulation for
the event in the snowbelt, especially inland NW PA. Lows Sat night
should fall into the low to mid 20s then only rise into the low 30s
east to around 40 west for Sunday.
A flatter more zonal flow later sun Thu Mon night will allow a
series of weak upper disturbances to quickly move east across the
area trying to induce some light precip. However, lower levels
appear too dry until late Sun night or Monday for anything more than
flurries. Temps should warm enough so that by the time any
worthwhile precip gets going on Mon, it should come mostly in the
form of rain.
The main upper trough digging over the west sends another weak S/W
ENE into the area for Tue which could enhance overrunning along the
warm front over the area Mon night and result in a little more
enhanced precip. Precip type appears in question as temps aloft will
be continuing to slowly warm. Right now the models indicate the the
SSW half of the cwa should see just rain with only the far NE seeing
a good chance to see more snow than rain.
Long term /Tuesday through Saturday/...
scattered to numerous showers expected to be ongoing Tuesday morning
as stalled boundary lifts back north as a warm front. Temperatures
expected to surpass the 50 degree mark in all areas again as the
front lifts to the north, although may take until late in the day to
clear the Lakeshore areas. A low level jet is expected to slide
overhead on Tuesday night as low pressure slides northeast from the
plains to the central Great Lakes. This jet should provide enough
lift for scattered showers to develop again overnight. Upper level
trough is forecast to deepen over the plains Tuesday night before
curling northeast towards the Great Lakes on Wednesday. Moisture
will surge north into the area ahead of this system and expect
showers in the southeast initially to expand with the passage of the
cold front. Given ample cloud cover and periods of showers kept
highs on Wednesday in the mid 50s, except closer to 50 in tol. Much
colder air wraps in behind the system with lingering precipitation
transitioning to snow showers on Wednesday Night. Lake effect snow
showers will linger downwind of Lake Erie on Thursday and Thursday
night then decrease on Friday as moisture dwindles and a ridge
Aviation /18z Saturday through Thursday/...
cold front now well southeast of the forecast area. Secondary trough
will move across the area this evening. Some scattered snow
showers with the trough...with little or no accumulation. After
that mainly just flurries for most locations. Lake effect snow
showers will develop across the northern snowbelt overnight as
850mb temps dip to -14c. West winds gusting into the lower 30s
will gradually diminish after sunset. High pressure will build
in Sunday afternoon cutting off the snow.
Outlook...-shsn across the snowbelt Sunday morning. Areas on
non-VFR Monday and Tuesday, returning Wednesday night.
cold front will shift east of Lake Erie this morning with winds
increasing as cooler air spreads over the lake. The Small Craft
Advisory is already in effect on the western basin and will begin at
10 am from Cleveland eastward. Winds expected to increase to 30
knots this afternoon and will approach gale force on the far east
end of the lake for a couple hours this evening. Winds will decrease
from west to east into Sunday morning with the Small Craft Advisory
ending on the east half of the lake as winds back to the southwest
by late morning.
A ridge will build over the lake on Monday then shift east on
Tuesday. A series of low pressure systems will slowly move east
across the lakes from Tuesday night through Wednesday night. Winds
will increase considerably on Wednesday night with the passage of a
cold front as the low moves off to the east.
Marine...Small Craft Advisory until 10 am EST Sunday for lez146>149.
Small Craft Advisory until 4 am EST Sunday for lez142>145.