055 
fxus63 koax 180844 
afdoax 


Area forecast discussion 
National Weather Service Omaha/valley NE 
344 am CDT Friday Jul 18 2008 


Discussion... 


Timing and location of convection will provide the main forecast 
challenges the next few days. Upper air charts from 00z showed a 
decent amount of lower and middle tropospheric moisture in place 
over the plains. There was a weak thermal trough at 500 mb from 
western Montana into northern Utah. Strongest winds at 300 mb 
stretched from Oregon across the northern U.S. Into Ontario 
Canada. Water vapor loop showed a good feed of moisture from 
Mexico across the Desert Southwest and into the Central Plains. 
Radar loop indicated that the strongest storms had moved down 
into Kansas...with some lingering farther north in our area. A 
fairly strong complex of storms was also noted from parts of 
Wyoming into western South Dakota. Surface analysis was somewhat 
contaminated due to thunderstorms earlier in the night...but a front was 
discernible from low pressure over Wyoming over northern Nebraska 
..northwest Iowa and southeast Minnesota. 


There is some model agreement in the large scale features...but 
confidence is not overly high in any one solution. Will keep the 
fairly high probability of precipitation going from previous forecast in the south...and 
taper probability of precipitation down to the chance category north. Decided to drop the 
Flash Flood Watch over the southern zones for now. Already have 
other Hydro products handling the situation. Heavier precipitation may hold 
off until later today or this evening...and day shift may be able 
to get a better handle on things. Stayed fairly close to guidance 
for highs today...generally 80 to 85...due to expected cloud cover 
and precipitation. 


Tonight...will hold onto likely probability of precipitation for about the southeast 1/2 
of the area...but the best chance of thunderstorms and heavy rain should 
shift into Iowa by late in the night. Expect lows in the 60s. On 
Saturday...models have some agreement that highest chance of precipitation 
will be to our north and east. Southern zones should see the most 
sunshine...so went with lower 90s there...with middle or upper 80s 
elsewhere. 


Models show a tendency to build a middle tropospheric ridge across 
the southern and Central Plains next week. This seems reasonable 
based on a typical late July pattern. For now...did not make many 
changes beyond Sunday...other than some minor smoothing. 


&& 


Aviation... 


For taf sites koma/klnk/kofk. 


Variable conditions expected at taf sites through much of the period. 
Some chance of thunderstorm activity again mainly for koma and klnk after 
21z. 


&& 


Oax watches/warnings/advisories... 
NE...none. 
Iowa...none. 
&& 


$$ 


Discussion...Miller 
aviation...fobert