903 
fxus61 kcle 030904 
afdcle 


Area forecast discussion 
National Weather Service Cleveland Ohio 
404 am EST Wednesday Dec 3 2008 


Synopsis... 
high pressure over the middle Atlantic coast will move offshore 
tonight and allow a strong cold front to move through the area. 
The front will move east of the region Thursday. A broad area of 
high pressure will settle into the nations middle section for Friday. 


&& 


Near term /until 6 PM this evening/... 
high pressure is over the middle Atlantic coast this morning and will 
slowly continue east as a strong cold front moves into the Central 
Lakes. Between these two systems a vigorous southwest flow will 
develop with 40kts at 850mb over the area by middle afternoon 
directly out of the Gulf of Mexico. Area will be ni warm advection 
through the day however expect some of this energy to go into 
isentropic lift as well. With increasing moisture across the area 
expect clouds to increase through the day. Sky condition however will 
still be tricky as we will likely see a breaks in the clouds from 
time to time. At this time though am leaning toward mostly cloudy. 
Afternoon temperatures generally in the 40s. Will need to bring in a 
chance of rain in the afternoon west and slight chances central 
zones. By 00z this evening the NAM and GFS are showing deep 
moisture and decent lift across the northwest. 


&& 


Short term /6 PM this evening through Friday night/... 
tonight the cold front moves across the area and by 12z Thursday 
should be on top of Keri. Expect a good chance for precipitation with the 
low level forcing and deep moisture. Continued with categorical probability of precipitation 
for the area overnight. Expect rain to change to snow west to east 
as the cold air deepens across the area. Changeover should occur 
in the northwest by late evening between 9pm and midnight. 
Changeover will occur around 4-5am kcle and towards morning Keri 
although higher elevations could change earlier. Will go with snow 
accums around an inch or so for the area. Thursday expect lake 
effect snow to begin and move into northestern Ohio and northwestern PA. 
Positives include -8c to -12c at 850mb over the lake and a strong 
short wave moving onto the lake by evening. Negatives include 
high pressure quickly building toward the area. Drier air moving 
in and a northwest/short fetch from around 300 degrees vs a longer 
fetch. In all will have snow showers in the forecast and for now 
will hold accums in check at 1 to 3 or so. Thursday night and 
Friday expect More Lake effect snow showers but continue to 
question intensity since the high will be moving across the lower 
Ohio Valley and dry air continues to move across the lake. Winds 
will also be backing as the high drifts to our southeast Friday 
night into Saturday. 


&& 


Long term /Saturday through Tuesday/... 
not much change for the weekend. GFS continues to show a clipper 
system moving through the Great Lakes region as high pressure 
spills into the Central Plains. These systems will provide a 
reinforcing shot of cold air on Sunday with 850mb temperatures dropping to 
-14 to -16 early in the day. Again expect lake effect snow to 
develop across northestern Ohio and northwestern PA. High pressure will be across 
the area on Monday followed by another low beginning to move into 
the Great Lakes region from the west on Monday. Tuesday the 
low will weaken however an associated cold front will drop across 
the area. 


&& 


Aviation /08z Wednesday through Sunday/... 
clearing is pushing into northwest PA. South breeze will stay up 
overnight. Patchy middle/high clouds and VFR conditions will continue 
until rain showers develop with the next cold front which should 
reach Northwest Ohio toward dark Wednesday and move east across all taf 
sites early Wednesday night. MVFR ceilings/visibility should develop with the 
onset of showers Wednesday night. 


Outlook...IFR ceilings possible for a short time after frontal 
passage early Thursday morning. Rain will end early Thursday and 
drier air will push in but MVFR stratocumulus will likely linger 
especially across NE Ohio/northwest PA where lake effect snow showers will 
develop. Series of troughs will swing across the area late in the 
week right through the weekend with MVFR ceilings and IFR visibility 
during snow showers. Most of the snow showers should be confined 
to the snowbelt of NE Ohio/northwest PA except on Saturday when the entire 
area will be affected by a clipper system and cold front. 


&& 


Marine... 
after coordination with the canadians...Buffalo...and Detroit...gale 
warnings will be posted with this package as models indicate a 
fairly strong 50 knot low level jet southwest to northeast across 
the lake later this afternoon into tonight. Flow becomes slightly 
more southerly aloft and this will reduce some of the fetch and will 
likely push the cold dome of air over the Lake Down wind. This 
should allow the stronger winds to push to the surface. The cold 
front will pass through the lake during the night and this should 
shunt the higher winds off to the east. Surface gradient weakens and 
winds aloft weaken as well so Gale Warning will be short lived. 
Small Craft Advisory will then take over during the day Thursday and 
be up through at least Saturday morning. I anticipate small craft 
advisories can be dropped Saturday afternoon into Sunday. 




&& 


Cle watches/warnings/advisories... 
Ohio...none. 
PA...none. 
Marine...Gale Warning from 9 PM this evening to 7 am EST Thursday for 
lez061-149-169. 
Gale Warning until 4 am EST Thursday for lez142>148-162>168. 


&& 


$$ 
Synopsis...tk 
near term...tk 
short term...tk 
long term...tk 
aviation...kosarik 
marine...Lombardy