507 
fxus63 kdlh 101207 cca 
afddlh 


Area forecast discussion...corrected 
National Weather Service Duluth Minnesota 
603 am CST Wednesday Mar 10 2010 


Aviation... 
low pressure to the south of the forecast area will spread rain and 
IFR/LIFR conditions northward over the region today...becoming 
widespread by the afternoon. The IFR/LIFR flight restrictions will 
persist through taf period. There may be slight periodic impvmts to 
ceilings in between waves of rain...mainly over Wisconsin where drier 
air tries to migrate north and west. Generally...MVFR/IFR conds will 
persist for the rest of the work week. 


Note that the ceilometer at kinl is out. Equipment is expected to 
be fixed some time this morning. Taf will reflect the best 
estimate based on synoptic situation and surrounding stations. 
Amendments will not be issued for ceilings until the equip is 
back in operation. 


&& 


Previous discussion... /issued 315 am CST Wednesday Mar 10 2010/ 


Discussion...short term forecast challenge is on precipitation. Surface low 
center at 08z was in south central Iowa with an inverted surface trough 
snaking northward to near the western County Warning Area border. First wave of 
light precipitation...mostly dz...lifting northwestward through the 
southern portion of the forecast area at 08z. Areas of fog across much of the 
forecast area at this time. 


Surface low center forecast to reach SW Minnesota by 00z Thursday. Waves of 
precipitation will be sent northward ahead of the surface low and is moving 
though southern Minnesota and southern WI at this time. This precipitation will affect the 
forecast area today. The exception will be along the international border area 
which may escape the precipitation initially as drier air between the 
boundary layer and about 5k feet will take awhile to overcome. Precipitation 
type will be all liquid as seen on forecast soundings and have 
removed mention of freezing rain today. Areas of fog over the forecast area with warm 
boundary layer/melting snow/rain. 


SW Minnesota surface low dissipates tonight while upper low recharges in the 
plains and develops a bit stronger surface low into northwest MO by 12z 
Thursday. Meanwhile...an inverted surface trough will be over the Red 
River valley. After a period of showers in the evening...expect the 
rain to diminish for a time tonight. Some rain will still be found 
over the northern tier of the forecast area as short wave energy rotates 
through this area. With a light wind anticipated...fog will 
continue to be prevalent. Have held off on the mention of widespread 
fog at this time as the lingering showers/dz may keep visibilities from dropping 
off. 


Thursday finds the upper low making its way northward to near the 
Iowa/MO border area...with the surface low in the vicinity. 
However...pieces of upper level energy will rotate towards and 
through the forecast area justifying the continued mention of light rain. A 
good shot of warm air advection on Thursday will push maximum temperatures up a bit which will 
keep the precipitation in the liquid form. The rain and warm temperatures will 
continue to melt snow and fog will prevail. 


Extended...Thursday night through Sunday. 
The western Great Lakes will remain in an active pattern on the northern flank 
of a cut off low under cyclonic flow through the extended period. 
The double barrel low currently seen on WV/infrared imagery spinning over 
Kansas and New Mexico will merge into a single stacked low over the cen 
plains Thursday...becoming cut off from main upper level flow. This will 
allow for the system to remain nearly stationary rotating over 
Iowa/NE/IL region through rest of the week and into weekend. Although 
the exact location of the low center/vorticity is still somewhat 
uncertain and timing the exit of cut off lows is notoriously 
difficult for models...confidence high enough that the forecast area will be in 
a position to see prolonged -ra/dz continued upward trend in probability of precipitation 
for end of the week. Since there will be no change in current air 
mass over the region...temperatures will continue to be 
mild...generally in the 40s during the day and middle 30s overnight. 
Winds through prd will be easterly...with a gusty NE flow over 
Lake Superior...keeping adjacent areas near steady in the 35 to 40 
degree range. 




&& 


Point temps/pops... 
dlh 39 31 42 35 / 70 60 40 60 
inl 41 30 41 32 / 20 70 40 40 
brd 41 33 42 34 / 70 60 60 70 
hyr 46 35 48 36 / 70 50 50 70 
asx 42 34 45 36 / 70 50 30 60 


&& 


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


$$ 


Gsf/graning/graning