430 
fxus63 kdlh 080403 aac 
afddlh 


Area forecast discussion...updated 
National Weather Service Duluth Minnesota 
1103 PM CDT sun Sep 7 2008 


Update... 
removed showers and decreased clouds across the area. 


&& 


Discussion... 
showers have dissipated. Skies upstream over western Ontario are 
clearing rapidly. With residual low level moisture...decoupling 
and decreasing winds...we ancpt the development of a shallow 
nocturnal inversion and the consequent development of patchy 
inland fog. This fog and moisture will protect most areas from 
frost tonight. 


&& 


Previous discussion... /issued 930 PM CDT sun Sep 7 2008/ 


Update... 
removed thunderstorms. Removed showers except for the Rainy River 
valley...the eastern Iron Range...The Arrowhead and areas east of 
Bayfield peninsula before 100 am and all precipitation thereafter. 
Made patchy fog more widespread late tonight. 


Discussion... 
showers are diminishing except along the Canadian border and 
throughout The Arrowhead. Showers in Canada moving toward the 
eastern arrowhead should diminish late tonight...the back edge of 
those clouds have gotten southeast of Red Lake and it continues to 
move steadily southeast. We ancpt showers east of Bayfield 
peninsula in northwest Wisconsin will soon be gone...but midnight 
anyway. With residual humidity and a tendency for nocturnal 
inversions to form with decreasing winds inland...we expect fog 
rather than frost inland tonight. 


Previous discussion... /issued 649 PM CDT sun Sep 7 2008/ 


Update... 
increased and lengthened evening showers to 100 am Monday and 
retained isolated thunderstorms...across the entire area. 
Increased offshore winds...especially around Lake Superior. 


Discussion... 
again...we have a column that is cooling aloft faster than the 
surface. Dew points at or below 10c are again a feature...this scenario 
has gone on for four days now...where supposedly diurnal showers 
increase in intensity near and after sunset and finally die away 
in the hours just after midnight. With cold advection aloft...a 
weak vorticity ridge on the models and a surface trough well northwest 
of the model position...through The Arrowhead into the eastern 
Iron Range we ancpt convction will continue. We also ancpt that 
convection will not be locally intense as yesterday evening/S was 
but will feature isolated thunderstorms. A falling freezing level 
may well result in small hail across a number of areas until midnight. 


Previous discussion... /issued 233 PM CDT sun Sep 7 2008/ 


Discussion... 
shortwave...cold air aloft...and a cold front all helping drive 
the showers/storms this afternoon. The freezing levels are quite 
low...and we've received a couple reports of pea size hail or 
smaller. Strongest storms have been occurring across northwest 
Wisconsin...ahead of the front. 


Most of the showers/storms are diurnally driven/enhanced at this 
point...and should weaken or dissipate toward or shortly after sunset. 


We are concerned with frost potential tonight. There are a few 
negatives or question Marks regarding frost though. Dewpoints are 
rather high over and just upstream of our County Warning Area. Most of the cloud 
cover is open cumulus...and quite a bit of it will dissipate overnight. 
Although winds will diminish overnight...the center of the high 
will be to the west and we don't expect calm winds. We will 
continue to mention patchy frost tonight...but evening shift will 
have to watch closely and may need to issue an advisory. 


Cold air aloft will remain on Monday...and we will continue to 
mention isolated showers/storms. There is a lack of a stronger 
wave like today...so probability of precipitation will be a bit lower. 


Frost expected Monday night...but unsure whether we'll need an 
advisory or not. Models showing more clouds possible...so 
confidence in a widespread event is low at this time. 


Tuesday looks like a dry day as southerly flow starts to draw 
warmer air north. A stronger system will move in for Wednesday 
into Wednesday night...and bring a chance for rain/storms. 


Aviation... 
scattered showers and thunderstorms will continue 
through about 02z this evening as a rather strong shortwave and 
surface cold front push east through MN/WI. Ceilings and 
visibilities will generally remain low-end VFR through the evening 
hours...but will occasionally drop to MVFR in heavier showers or 
storms. Cold temperatures aloft...associated steep lapse rates and 
modest instability will result in small hail with some of the storms 
through about sunset. Weak ridging will bring a gradual decrease in 
cloud cover overnight with prevailing VFR conditions. 
However...areas of fog may once again develop after 06z...mainly 
confined to the favored locations. As another shortwave passes to 
the south on Monday...clouds will gradually increase during the 
morning hours with the potential for additional showers and storms 
after 18z...especially in the southeast portion of our 
area...including khyr. 


&& 


Point temps/pops... 
dlh 39 59 40 64 / 10 20 20 10 
inl 36 58 35 65 / 10 20 20 10 
brd 38 60 36 66 / 10 20 20 10 
hyr 36 59 34 65 / 10 30 20 10 
asx 39 59 35 65 / 10 20 20 10 


&& 


Dlh watches/warnings/advisories... 


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


$$ 


Eom/tl