052 
fxus63 kdlh 220255 aaa 
afddlh 


Area forecast discussion...updated 
National Weather Service Duluth Minnesota 
855 PM CST Friday Nov 21 2008 


Update... 
will update zone forecast product by 930 PM. No big changes planned. Will decrease 
cloud cover a bit over southwestern County Warning Area. Middle/high cloud deck will probably not 
move much farther north as associated shortwave continues to head to the southeast...as 
indicated by satellite loops. Consequently...will lower mins a couple 
of degree...mainly over Iron Range and northwestern WI. Some low cloud elements 
moving across arrowhead...so did not adjust temperatures up there. Have also 
decreased wind speeds a tad as radiational invsn sets up and surface 
winds decouple. This should limit wind chills to the middle teens 
below zero. 


&& 


Previous discussion... /issued 243 PM CST Friday Nov 21 2008/ 


Discussion... 
short term focus revolves around low temperatures and cloud cover 
tonight...and the potential for freezing drizzle Saturday night. 


Current surface analysis depicts high pressure centered over 
southwest Ontario...with low pressure and an associated shortwave 
over the western Dakotas. Clouds have decreased substantially 
during the day...except in the snowbelt of Wisconsin...where 
plenty of low clouds remained in place...as northwest flow and 
some remnant cyclonic flow destabilizes the low levels. 
However...even here...clouds have broken up markedly in the past 
two hours. Snow showers have also gradually diminished in 
intensity across Ashland and Iron counties...with little 
additional accumulation reported from spotters during the day. 
Area webcams by early afternoon continued to show some occasional 
flurries or light snow showers...but much of this activity will 
diminish by late afternoon as winds continue to turn more 
westerly...inversion heights lower further. 


As high pressure settles overhead tonight...and skies turn mostly 
clear...temperatures will drop rapidly...especially during the 
evening hours. There could be some increase in high clouds in the 
western portion of the area...especially after midnight. 
Additionally...the warm air advection regime will become more established and 
surface winds may actually increase just a bit late. 
Still...given several hours of optimal cooling conditions...we 
generally went with min temperatures at or slightly below the coldest 
guidance. Isolated areas in The Arrowhead and Iron Range will 
likely dip to -5 or below...and portions of northwest wisc will approach 
these readings. 


Low and middle level moisture will begin to increase by Saturday 
evening as the aforementioned shortwave draws closer to the 
region and warm air advection becomes more robust. Dry air remains in place 
aloft...but forecast soundings...particularly the NAM...show the 
potential for patchy freezing drizzle and flurries. Confidence is 
not high...and while quantitative precipitation forecast will be minimal and spotty...this could 
create some travel concerns. By Sunday...the upper level low and 
cold front will cross the area...with some light snow. 
However...the snow may be mixed with rain...at least 
initially....over the southern half of the region as surface-850 mb 
temperatures warm above freezing for at least a few hours. Quantitative precipitation forecast 
will remain light. 


As low pressure deepens over southern Canada on Monday...another 
reinforcing shot of cold air will sink southward...with periodic 
snow showers and the potential development of lake effect snow 
along the South Shore through Monday night. Temperatures will 
begin to moderate on Tuesday as the upper level flow turns more 
zonal. Ridging will build toward the Thanksgiving Holiday with 
mainly dry conditions. 


Aviation... 
skies have cleared this afternoon...and expect VFR conds through 
the taf period. Only some increase in high cirrus is expected 
later tonight through Sat morning. High pressure overhead will move 
steadily southeastward...with winds becoming southeast by this 
evening. 


&& 


Point temps/pops... 
dlh 2 28 18 35 / 0 10 10 20 
inl -3 26 15 31 / 10 10 10 20 
brd 9 30 22 38 / 10 10 10 20 
hyr -3 32 19 37 / 0 10 10 20 
asx -2 30 20 36 / 10 10 10 20 


&& 


Dlh watches/warnings/advisories... 


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


$$ 


04