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afdoun 


Area forecast discussion 
National Weather Service Norman OK 
1045 PM CST Thursday Nov 20 2008 


Aviation... 
wind speeds will continue to slowly decrease as surface pressure 
gradient weakens. High clouds over the area will diminish from the 
northwest late tonight and Friday morning as short wave trough clears the 
area. Southerly winds will return Friday as Lee trough develops in 
advance of next upper system. 


&& 


Previous discussion... /issued 953 PM CST Thursday Nov 20 2008 


Update... 
wind continues from the north at 15 to 20 miles per hour across much of the 
County Warning Area this evening...but is beginning to die down in northwest zones. 
Continuing winds have slowed the temperature drop thus far 
tonight...helped along by some middle level cloud cover. The trend 
over the last 3 to 4 hours has shown thinning of clouds. 
It is Worth noting that in northwest OK where wind speeds have dropped 
off temperatures have fallen into the middle 20s despite the presence of 
cloud cover. It is not going to take a very long period of calm 
winds or clear skies to allow low temperatures to drop to forecast values 
so will leave them as is. 


Wind speeds have been adjusted in the grids to reflect the 
pressure field...and minor changes have been made to sky grids as 
well. 


&& 


Previous discussion... /issued 246 PM CST Thursday Nov 20 2008/ 


Discussion... 
will allow Wind Advisory to expire at 4 PM. Winds have been on the 
decrease and expect stronger wind gusts will be confined to parts of 
southwest OK and west North Texas by middle to late afternoon. The lower 
clouds across northwest Oklahoma should gradually decrease this 
evening leaving mainly scattered-broken high clouds. Winds should become 
light and variable by Friday morning so a hard freeze is in store 
for most locations. Winds will return to a southerly direction by 
Friday afternoon as the surface high shifts to the east and another 
fast moving system tracks across the northern plains. 


Breezy and cool conditions can be expected Saturday. Moisture and 
low clouds will lift back into the Southern Plains ahead of another 
cold front. Central and eastern Oklahoma will likely have low clouds 
and maybe areas of fog/drizzle late Saturday into Sunday morning. 
Another cold front will move across the area late Sunday into 
Monday morning. Airmass behind this front will not be extremely 
cold...but airmass will be rather dry. 


12z ec/GFS begin to diverge with regards to West Coast trough by 12z 
Tuesday. The GFS solution would result in a frontal passage late 
Wednesday into early thursday(thanksgiving) with mainly cool and 
dry conditions. Ec and ensembles suggest a cloudy possibly wet 
and foggy Thanksgiving. At least the chances for wintery type 
precipitation looks low at this time. 


&& 


Preliminary point temps/pops... 
Oklahoma City OK 24 45 30 55 / 0 0 0 0 
Hobart OK 25 50 30 56 / 0 0 0 0 
Wichita Falls Texas 26 50 33 62 / 0 0 0 0 
gage OK 17 47 25 58 / 0 0 0 0 
Ponca City OK 22 44 29 54 / 0 0 0 0 
Durant OK 28 48 31 55 / 0 0 0 0 


&& 


Oun watches/warnings/advisories... 
OK...none. 
Texas...none. 
&& 


$$ 


03/02