352 
fxus61 kcle 231528 
afdcle 


Area forecast discussion 
National Weather Service Cleveland Ohio 
1028 am EST Monday Nov 23 2009 


Synopsis... 
high pressure ridge over the area will give way to a weak low 
pressure system that will track northeast along the Appalachians 
today. High pressure will build over the area Tuesday but quickly be 
replaced by the passage of a warm front associated with low pressure 
over the plains. This low pressure and cold front will push through 
region Wednesday. Colder air is still expected for the end of the 
week. 


&& 


Near term /through tonight/... 
updated to remove morning wording and update cloud cover. Rest of 
forecast looks reasonable. Rain looks impressive on the 
radar...but only getting a few hundreths across soutern Ohio and 
Kentucky. Will just leave chance probability of precipitation going. 


High pressure continuing to ridge into the area this morning. 
Surface analysis showing weak low pressure centered over eastern 
Kentucky. This low is expected to track northeast through the day today. 
Surface observation and regional radar indicating some showers across eastern 
Kentucky and WV at this time. Looking at 00z sounding from iln and pit 
it looks like these showers will have quite a bit of drier air to 
overcome before reaching the ground. Do have slightly higher probability of precipitation 
across the east for early tonight but still only chance for lack 
of coverage purposes. For temperatures today went with a blend of 
mav and met guidance. Sunshine this morning will give a good start 
to temperatures but increasing clouds will limit additional rises through 
early afternoon. Expecting coolest temperatures across southeast areas 
while northern zones especially along Lakeshore could top out 
warmest since they will be last to get into the clouds. 


&& 


Short term /Tuesday through Thursday night/... 
gradually reduced probability of precipitation back through tonight with weak low pressure 
pulling away from the area to the northeast. High pressure will 
briefly build into the area for Tuesday but do not expect good 
clearing with the high with lingering low level moisture and lack of 
gradient. With little change of airmass expecting temperatures to climb 
back into lower 50s on average across the area. 


Increased probability of precipitation from west to east through Tuesday night. By Wednesday 
morning indicating high chance across the west...tol-fdy with still 
only slight chance by morning across the east. Models fairly 
consistent now with bringing cold front through the region by 
Wednesday evening. While guidance probability of precipitation still showing chance for 
showers at locations across the region...went slightly higher to 
likely as given expected conditions feel fairly confident most of 
the area will see showers at some point through the day. Went close 
to guidance temperatures for Wednesday...at or slightly above 50. Thinking that 
may not be unreasonable with cold frontal passage since min temperatures 
for Tuesday night are going to remain mild with lows in lower to middle 
40s. 


Continued with chance probability of precipitation on Thursday as GFS European model (ecmwf) and Canadian showing 
surface low pressure over central Great Lakes. Models also rather 
consistent in bringing closed upper low over the area Thursday night 
and then pushing it off to the east Friday. Continued trend for the 
end of the week with temperatures cooler than guidance and chance probability of precipitation for 
snow showers. 


&& 


Long term /Friday through Sunday/... 
European model (ecmwf) and GFS are similar with a deep upper low diving well to the 
south across the Ohio Valley on Friday and then pulling out early in 
the weekend. Gem remains more conservative with the upper low/trough 
crossing the Great Lakes which would seem more in line with 
climatology. A deeper trough would provide colder air aloft and more 
potential for significant precipitation farther south...at least 
some of the precipitation likely in the form of wet snow. For 
now...will keep the forecast generic and wait for more confidence as 
we get closer to the end of the week. Trough and deepening surface 
low pressure system will be pulling out early in the weekend. Wrap 
around precipitation including lake enhanced/lake effect will 
continue across NE Ohio/northwest PA into Saturday. By late Sunday then next 
cold front will already be making progress across the Midwest and we 
should see some brief ridging ahead of the front. 


Lowered forecast maximum temperatures for Friday and Saturday compared 
to guidance which has temperatures near normal. Feel more 
comfortable with forecast maximum temperatures a category or two below 
normal given that we will have a deep trough aloft and a threat of 
snow. 


&& 


Aviation /16z Monday through Friday/... 
a little early morning fog/haze/mist will dissipate as drier air in 
the low layers advects in on the east wind this morning. Middle/high 
clouds will increase today as upper trough moves north. Lower 
srtatocumulus will develop from south to north. Will be difficult 
for the rain to overcome the dry boundary layer but a few light 
showers/sprinkles will develop middle to late afternoon into the 
evening hours. As the boundary layer becomes saturated tonight it 
is likely that IFR ceilings will develop. 


Outlook...non-VFR conditions...mainly low ceilings... will 
continue well into the day Tuesday and again Wednesday through 
Friday at times. 


&& 


Marine... 
the east wind on Lake Erie overnight was stronger than I would have 
thought but as the gradient veers more toward the southeast the wind 
and waves should settle down today and remain relatively quiet on 
Tuesday. The south wind will pick up again ahead of the first cold 
front on Wednesday. After the frontal passage an increasing 
southwest gradient will likely lead to Small Craft Advisory. A 
deepening low pressure system and stronger cold front later 
Thursday/Thanksgiving day should open the door to strong cold 
advection and a perhaps a Gale Warning by the end of the week. 


&& 


Cle watches/warnings/advisories... 
Ohio...none. 
PA...none. 
Marine...none. 


&& 


$$ 
Synopsis...Abe 
near term...Abe/djb 
short term...Abe 
long term...kosarik 
aviation...kosarik 
marine...kosarik 

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