230 
fxus63 kdlh 200844 
afddlh 


Area forecast discussion 
National Weather Service Duluth Minnesota 
344 am CDT Sat Mar 20 2010 


Discussion... 
quiet and dry short term with rebounding temperatures through the 
early half of next week. Only minor adjustments to temperatures 
in the first few periods closer to lav/met guidance. Current surface 
analysis shows broad area of surface high pressure over the Dakotas 
with a ridge axis extending east over northern Minnesota. Clear skies and light 
winds overnight has allowed for temperatures to drop below 
normal...for the first time since the first week of March...with 
readings in the teens. 


Sunny skies and west winds will prevail today as the forecast area is 
positioned between a northern stream low over Hudson Bay...and a southern 
stream low over the Southern Plains. Zonal flow aloft between the two 
systems will persist through the weekend. A warm air advection regime will 
shift east into the forecast area this afternoon...ushering the cool air mass 
currently residing over the upper Midwest off to the east. A 
30-40 knots jet streak will allow for thickness rises and 850 mb 
temperatures to quickly warm overnight. The NAM/ecm agree that 850 mb 
readings increase from around -10 c this afternoon...to near 0 c by 
12z sun. The GFS is a few degrees cooler. A vorticity maximum will will 
track quickly southeast over Manitoba/Ontario...skirting along the international 
border...late tonight and Sunday. No precipitation is expected with the 
vorticity...but the southern edge of the clouds will nudge into the far northern 
zones during this time. A tightening baroclinic zone will set up 
along the international border in the wake of the vorticity Sunday. This 
boundary will bring a large surface temperature gradient to the northern zones and 
difficulty in fcsting high temperatures in this region Sunday. Increasing 
confidence in the southern half of the forecast area will reach the low/middle 50s 
Sunday. 


Extended...Sunday night through Wednesday.... 
County Warning Area remains primarily under the northern branch of a split flow in the 
westerlies through the period. Frontal boundary that pushed into region 
Sunday will stretch across County Warning Area early Monday...before lifting north 
during the day.Although isentropic ascent is expected with front 
pushing north...latest conditions press deficits suggest saturation will 
not be sufficient in lowest layers to mention precipitation. Northern branch 
amplifies late Monday into Tuesday. Models differ on placement and 
strength of middle level/surface features. Enough of a general consensus that 
a second cold front will push across the region by Tuesday 
afternoon. Inherited grids in decent shape so no major changes made 
to probability of precipitation/ptype for the frontal passage. Ec/Gem keep any accumulation 
near international border...while typically colder and wetter GFS 
pushes some accumulations much farther south. Given uncertainty in 
thermal fields this far out...low confidence in any solution. Quick 
middle level flow will bring a brief period of surface ridging Wednesday 
before warm advection regime returns Wednesday night/Thursday. Maximum temperatures 
Tuesday/Wednesday may need adjustment downward as latest ec/mex have trended 
cooler from previous model cycle. 


&& 


Aviation.../6z taf issuance/ 


High pressure over the northern plains will continue to give VFR 
conditions throughout the taf period. Northwest winds will gradually back 
to west-southwest by the end of this taf cycle. 


&& 


Point temps/pops... 
dlh 36 24 49 31 / 0 0 0 0 
inl 37 22 40 24 / 0 10 10 0 
brd 37 24 51 31 / 0 0 0 0 
hyr 41 20 51 25 / 0 0 0 0 
asx 39 24 50 25 / 0 0 0 0 


&& 


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


$$ 


Graning/Cannon