Weather

067 
fxus63 kbis 292003 
afdbis 


Area forecast discussion 
National Weather Service Bismarck ND 
305 PM CDT Friday Aug 29 2008 


Short term...Friday night through Monday night 
upper level ridging tonight and Saturday will bring dry and hot 
weather. The NAM indicates 800 mb temperatures near 30c in the west and 
this will translate into surface temperatures in the 100 degree 
range. Also as Saturday progresses the ridge will move further east 
and the flow aloft will be become southwesterly promoting Lee side 
surface troughing and increasing southerly surface winds. 


Next...a deep upper trough will become the focus of our weather for 
the remainder of the short term forecast period. This trough will be 
slow to move east per all the models. At the surface a cold front 
will lie parallel to the upper jet so its progress to the east will 
be very slow also. So we will be under a threat of thunderstorms for 
several days. Additionally the warm to hot weather will persist east 
of the front. The forecast will show an increasing chance of 
thunderstorms...with the greatest probability of precipitation on Monday. 


I will be using the slower European model (ecmwf) for the timing of the frontal 
movement. 


Long term...Tuesday through Friday night 
models in good agreement in the long term. This period is dominated 
by upper level troughs which will bring a showery and cool trend in 
the forecast. 


On Tuesday a well-developed longwave trough with a closed low over 
the Front Range in Montana/Wyoming lifts northeast towards Lake 
Winnipeg. This will keep a good chance of showers and thunderstorms 
in the forecast for the area. Wednesday through Friday will be 
dominated by a broader upper level trough that sets up over Canada 
and the central US. 


Highs in the 60s and 70s with lows in the 40s and 50s during the 
long term period. 




&& 


Aviation... 
dry surface high pressure over the state this afternoon will move 
east into Minnesota tonight as low pressure develops in the Lee of 
The Rockies from Alberta to Colorado. Strong southerly flow will 
develop by 18z on Saturday with mainly clear skies tonight through 
Saturday afternoon. 


&& 


Fire weather... 
I will keep the watch for the western half of the state in effect. 
Rh's will meet criteria and so will the winds in most of the watch 
area. We may have to leave the northwest out of a potential warning 
as winds may be under 15 miles per hour there tomorrow. 




&& 


Bis watches/warnings/advisories... 
Fire Weather Watch from Saturday afternoon through Saturday 
evening for ndz001>003-009>011-017>021-031>034-040>045. 


&& 


$$ 


Rsl/jv