098 
fxus63 kdlh 151721 
afddlh 


Area forecast discussion 
National Weather Service Duluth Minnesota 
1221 PM CDT Monday Mar 15 2010 


Aviation...18z tafs. 
VFR at khyr until 07z Tuesday when MVFR visibility and ceilings are expected 
with fog development. Otherwise...a trend toward MVFR ceilings at 
remaining locations ahead of approaching upper level wave. Look 
for light rain to develop late this afternoon over the kbrd/kinl 
areas ahead of the wave. The rain will then spread into the 
khib/kinl around 00z...reaching khyr after 13z Tuesday. Some local 
IFR ceilings are possible overnight with fog. 


&& 


Previous discussion... /issued 621 am CDT Monday Mar 15 2010/ 


Aviation...update for 12z tafs 
winds have stayed up overnight...but with 1-3 degree dpd...still a chance of 
some MVFR visibilities in br for a couple of hours yet this morning. 
Othw...main issue will be MVFR ceilings/visibility in -ra and br overnight tonight. 
Not much of a surface system...but upper level shortwave will be passing ovhd 
with modest amount of lift and moisture. Lowest ceilings/visibilities will be vicinity 
brd where most of the energy and moisture will be concentrated. 


Previous discussion... /issued 343 am CDT Monday Mar 15 2010/ 


Discussion...latest kdlh radar imagery and Northland observations 
show isolated/scattered showers across our Minnesota zones early this 
morning. This activity is associated with a very weak upper level 
vortmax propagating through weak nwrly flow aloft. This activity 
is expected to linger across our Minnesota zones today...although it may 
diminish somewhat. However our main forecast focus for the short 
term is a stronger shortwave currently over Saskatchewan/Manitoba 
rotating over the top of a large upper level ridge over the 
mountain west. As the shortwave digs southeastward...it will strengthen as 
it moves away from anticyclonic flow around the ridge. The models 
show light rain developing or increasing in coverage across the 
western half our County Warning Area tonight in association with this stronger wave. 
The precipitation is not expected to spread all that far eastward due to 
the dry air over Lake Superior and southeastern Ontario. But scattered 
showers should affect the twin ports region...Iron Range and 
areas to the west and south tonight into Tuesday. Because of 
differences between model solutions...have only increased probability of precipitation to 
scattered at this time. Above to much above normal temperatures are again 
expected today for highs...with cooler conditions expected on 
Tuesday due to increased cloud cover and scattered showers. 


Extended...Tuesday night through sun. 
All models consistent in building upper ridge into the upper Midwest 
and western Great Lakes for a dry period middle week. Left Thursday dry as upper level 
system skims along cn border with main energy and moisture staying to 
the north. Then the issue becms the upper trough swinging across the northern 
tier states. Models show rather scarce mstr/qpf...but left in slight 
to low chance probability of precipitation due to strength of upper level lift potential. For the 
weekend...we will be dealing with the phasing of the northern branch 
trough with a southern branch impulse. Still some diffs among the models 
on the strength and track of the surface system...but it looks like 
the bulk of any precipitation will be to our S and east. Left weather/pop grids as 
is for now. Will be able to tweak timing and precipitation type as we get 
closer in time. 


Aviation.../06z taf issuance/ 
area of scattered -shra over western St. Louis County might clip hib 
over the next several hours so included vcsh. With more cloud 
cover already in place...not too confident to bring visibilities down 
before sunrise so included a tempo for patchy fog before sunrise 
with some MVFR visibilities possible. Slightly better chances for fog 
will be at hyr where there are more breaks in the clouds. MVFR 
ceilings move in to Minnesota taf locations by middle morning. 


&& 


Point temps/pops... 
dlh 35 45 33 52 / 30 30 0 0 
inl 34 45 27 51 / 10 10 0 0 
brd 34 45 29 50 / 30 20 0 0 
hyr 35 54 28 55 / 20 30 10 0 
asx 35 48 30 53 / 10 20 10 0 


&& 


Dlh watches/warnings/advisories... 
Minnesota...none. 
WI...none. 
Ls...none. 
&& 


$$ 


Graning/gsf