829 
fxus63 kdlh 182013 
afddlh 


Area forecast discussion 
National Weather Service Duluth Minnesota 
313 PM CDT Friday Jul 18 2008 


Discussion...main forecast challenge is resolving convective probability of precipitation 
in the short term. Afternoon surface analysis shows high pressure 
axis stretched across the Dakotas/Minnesota border. Departing short wave 
/skirting across Northern Lake Superior per water vapor loop/ 
today has resulted in some weak cold air advection across the dlh forecast area. Cumulus field 
that developed due to residual low level moisture should diminish 
with loss of daytime heating this evening. Tonight should remain 
relatively quiet except for potential fog development. Although 
not pinpointed by guidance at this time...weak easterly low level return 
flow setting up after midnight is expected to result in some fog 
development...especially as marine airmass advects onshore. 


Forecast attention then turns to next short wave in westerly flow 
aloft to lift east-northeast through the upper Midwest Saturday afternoon 
through Saturday night. Models show differing solution with 
progression of expected ongoing mesoscale convective system Saturday...especially between 
the NAM and GFS. NAM looks too far north with progression given 
instability fields are farther south. Therefore prefer the latest 
Canadian/European model (ecmwf) which skirt our southern counties. Airmass feeding 
into the mesoscale convective system is moist and unstable...but is also mainly south of 
the forecast area...so severe storms potential looks to remain out of the dlh forecast area 
at this time. Otherwise...just small chance probability of precipitation with warm air advection pattern for the 
remainder of the County Warning Area Saturday. 


Sunday...upper low currently over southern British Columbia/Alberta per water 
vapor...will push across south central Canada. Good fgen forcing and 
warm air advection lift will initiated convection in vicinity of surface trough/cold front as it 
pushes through Sunday. Moderate instability and 60+ knots middle level 
speed maximum will make some severe storms possible. 


Into early next week...looks like a drier pattern with seasonable 
temperatures setting up with northwest flow aloft and ridging just to the 
west. 


&& 


Aviation...weak ridging over the region will move east tonight...and 
lead to light winds...that will veer to more easterly by morning. 
Scattered to broken VFR cumulus will dissipate this evening...then 
expect a scattered to broken middle to upper deck. There is still 
adequate moisture around the region...and that will lead to areas 
of fog overnight...and eventually IFR conditions. The fog should 
burn off by middle to late Saturday morning for most areas...with the 
exception of around Lake Superior. An onshore wind around Lake 
Superior...may keep fog and or a IFR/MVFR stratus deck longer 
during the day. A warm front to our south will be the focus for 
thunderstorms...and most areas will have a chance at seeing a 
storm by afternoon or evening. Storms may roll into the Brainerd 
lakes and International Falls areas during the morning. 


&& 


Point temps/pops... 
dlh 56 70 55 72 / 10 30 30 30 
inl 50 77 53 76 / 10 30 30 40 
brd 56 78 59 82 / 10 50 30 20 
hyr 51 79 56 83 / 10 40 50 30 
asx 53 73 56 73 / 10 30 40 40 


&& 


Dlh watches/warnings/advisories... 


Minnesota...none. 
WI...none. 
Ls...none. 


$$ 


Liles/melde