Weather

492 
fxus63 kfsd 281527 
afdfsd 


Area forecast discussion for southeast South Dakota/southwest Minnesota/northwest Iowa 
National Weather Service Sioux Falls South Dakota 
1025 am CDT Thursday Aug 28 2008 


,discussion... 
lingrng middle clouds dcrsg stdly eastward out of forecast area as low clouds/fog southeast 
rapidly gets burnd off. A few clouds southeast from hetg before dry air moves 
in otherwise mosunny/sunny looks good for the afternoon. Temperatures looking pretty 
good...slowed drying of dewpoints slightly but it will happen. 


&& 
Aviation... 
fog/low clouds going quickly and by around 16z the last of the IFR 
ceilings/visibilities in northwestern Iowa should be gone. Very brief broken MVFR ceilings from 
heating possible there 16z-18z but ib afternoon as mentnd above strong drying will 
be felt even in northwestern Iowa. 


&& 
Previous discussion... 
a little lingering convection to deal with yet early this morning... 
otherwise pretty quiet forecast for most of the upcoming Holiday 
weekend. 


Actually a couple of areas of convection in the area early this 
morning. First and currently strongest is in far southern areas... 
south of the surface boundary which at 07z extended from extreme 
northestern Nebraska to near kspw-kest. Currently feeding off area of 
decent 850mb Theta-E advection ahead of the boundary...but this 
quickly wanes between 09z and 12z. Will carry a small pop past 12z 
to cover this...but very possible this activity could be southeast 
of the County Warning Area by then. 


Second area of precipitation is some middle level based rain showers/isolated thunderstorms and rain 
across the northwest County Warning Area...in enhanced 750-700mb frontogenesis on 
the south side of broad trough swinging through ND/far northern South Dakota. 
Lower levels drying out behind the front...but still seeing a little 
rain reaching the ground. Frontogenesis band extends from kmml-kfsd 
by 12z...and weakens quickly between 12z-15z as the upper wave pulls 
east. Will have to carry some isolated probability of precipitation for some areas along and 
north of I-90 early this morning...with gradual decrease in the middle 
level cloud deck as the wave moves away and drier middle level air 
works in behind the system. Most areas should see a decent amount of 
sunshine by late afternoon...with deep mixing in northwest flow 
pushing temperatures into the upper 70s-lower 80s. 


High pressure briefly moves through the County Warning Area tonight...with clear 
skies...light winds and dry airmass allowing for a cool night. Going 
lows in the middle 40s to lower 50s looked reasonable and made few 
changes. Will have to watch for fog potential around southeast County Warning Area 
with surface moisture from recent heavier rainfall in that area... 
but have not included at this time. 


High pressure moves quickly to the east on Friday...with southerly 
flow and warmer temperatures on tap for the Holiday weekend. Weak boundary 
tries to drop south into the far northwest part of the forecast area 
Friday night. Not much for moisture to work with...so do not expect 
more than a little increase in middle level cloud cover. Increasing 
warm advection pushes the boundary back to the northwest Saturday... 
with increasing winds and low level moisture through the weekend as 
upper ridge builds over the plains. Highs Saturday and Sunday should 
range from Lower-Middle 80s east to upper 80s-lower 90s west. 


Warmth continues into Monday with thermal ridge maximized over our 
County Warning Area ahead of digging trough and associated cold front which push 
across the western Dakotas through the day. 28/00z GFS and 27/12z 
European model (ecmwf) bring the cold front very near the western border of the County Warning Area 
by late in the day Monday...though 28/00z European model (ecmwf) now quite a bit 
slower with the eastward progression. Contemplated bumping probability of precipitation in 
the far west a bit for Monday afternoon with front approaching... 
but with slower timing on latest European model (ecmwf)...will stick with just slight 
chance for now. Should be warmest day of the weekend for central and 
eastern parts of the area with middle 80s to lower 90s expected most 
areas. 


&& 


Fsd watches/warnings/advisories... 


South Dakota...none. 
Minnesota...none. 
Iowa...none. 
NE...none. 


&& 


$$ 
Williams