Scientific Forecaster Discussion
fxus63 kdlh 192357
Area forecast discussion
National Weather Service Duluth Minnesota
657 PM CDT Thu Apr 19 2018
Short term...(this evening through friday)
issued at 313 PM CDT Thu Apr 19 2018
The northland's clear and calm weather will continue into tonight.
This afternoon's low humidity will help play into temperatures
dropping overnight into the low and middle 20s over most of the
region, but it could be colder in the teens in some areas. Leaned
on the colder model guidance.
There is a low probability of fog late tonight and early Friday.
The NAM, arw, nmm, and sref would suggest a high likelihood of
widespread fog, but I am leaning on the other models not
suggesting much fog because I do not believe there was much
melting of snow today to add much moisture into the atmosphere.
Plus, the snow and puddles will freeze again tonight with
temperatures plummeting into the 20s or lower.
High pressure will be centered south of the Northland Friday,
setting up light southerly winds. Sunshine will help temperatures
rise into the 50s again, and maybe even near 60 in far northern Minnesota
thanks to the sun beating on the Pine trees.
Long term...(friday night through thursday)
issued at 313 PM CDT Thu Apr 19 2018
Quiet through much of the extended with widespread precipitation
chances returning late Monday night through Tuesday and into early
High pressure will slowly build eastward from the western Great
Lakes on Friday evening into the eastern Great Lakes by late
Sunday. As the high gradually shifts further east, flow aloft will
become more southwesterly over time, which will advect milder air
into the region. Temperatures will be on the rise through the
weekend, highs on Saturday will be in the 50s while readings on
Sunday range from near 50 along the Lake Superior shoreline to
near 60 inland. Lowered daytime relative humidity values toward
the MOS guidance and sref (driest pieces of guidance) as the
pattern isn't too much different than today, and forecast relative humidity
values were higher than observed.
A positively tilted trough will lift across central Canada on
Sunday into early Monday. The warm front associated with the
system will lift through and bring slight chances of rain/snow to
the Minnesota arrowhead late Sunday night/early Monday morning. No
snowfall accumulation is expected. Skies will become mostly sunny
on Monday as high pressure nudges back into the region. Flow will
still be southwesterly, which will advect nearly 5 degree c 850
hpa air into the region. This will bring the mildest readings of
the extended with temperatures in the low 60s across the Brainerd
lakes and International Falls area.
Another trough will dig from the intermountain west and central
Canada into the northern plains late on Monday into Tuesday. At
the surface, an area of low pressure will develop somewhere across
the northern plains and move across the upper Mississippi River
valley. There are differences between the GFS/European model (ecmwf) and Gem
guidance with timing, strength and track of the system moving
through. Suspect the European model (ecmwf) is on the right track with a more
southerly solution, but opted with a blend of guidance due to the
large spread between guidance. Readings will cool down into the
upper 40s and low to mid 50s as the system moves through Tuesday
Aviation...(for the 00z tafs through 00z Friday evening)
issued at 644 PM CDT Thu Apr 19 2018
High pressure will bring quiet weather to the Northland throughout
the taf period. Some patchy fog could develop tonight, especially
in northwest Wisconsin. Other than that, we should see VFR
conditions tonight and on Friday.
Preliminary point temps/pops...
dlh 28 54 31 57 / 0 0 0 0
inl 25 57 29 57 / 0 0 0 0
brd 26 54 29 57 / 0 0 0 0
hyr 21 52 27 54 / 0 0 0 0
asx 26 54 30 55 / 0 0 0 0