Scientific Forecaster Discussion

Return to Local Conditions & Forecast

Without Abbreviations
With Abbreviations

fxus63 kdlh 211812 
afddlh

Area forecast discussion
National Weather Service Duluth Minnesota
1212 PM CST Tue Feb 21 2017

Update...
issued at 1205 PM CST Tue Feb 21 2017

Updated for new aviation section below.

&&

Short term...(today through wednesday)
issued at 352 am CST Tue Feb 21 2017

Sfc high pressure ridge is currently moving to the east, with the
axis over eastern North Dakota/western Minnesota border, which will
eventually advance over the Northland this morning. Areas of fog are
expected to expand eastward across the Northland due to weakening
winds along the sfc ridge axis. There is a low-level stratus cloud
deck overhead this morning, which has been holding strong this
morning. There does appear to be some breaks in the stratus near the
Brainerd lakes area, where some denser fog down to 1/4sm has
developed as indicated by sfc observations near Staples and Park
Rapids. Less dense fog has already developed near the Brainerd lakes
region, but hasn't reached dense fog criteria yet, although 1/2sm
was being reported at Pine River at 3:30 am CST. A dense fog
advisory may be needed for these areas this morning. Otherwise,
mostly dry conditions are expected for today as the high pressure
ridge advances through the region. The stratus deck looks to hang
tough through the morning hours before lifting a bit, and partly
to mostly sunny skies are expected for the afternoon. There is a
small chance of a rain shower along the international border as a
weak mid-level shortwave translates along this area.

Then, better chances of precipitation will develop along our
northern counties Tuesday night/Wednesday morning as a more robust
mid-level shortwave develops out of the intermountain west states
and into northern Minnesota. Thaler qg analysis shows decent
850-300 mb mean layer isentropic lift, along with a moistening
profile as indicated by GFS/NAM model soundings. Bumped up the
pops from the previous forecast as synoptic models are showing
better lift with this system. Precipitation types look to be
mostly rain at first before transitioning to a wintry mix
Wednesday morning. A trailing stream of positive vorticity
advection behind the leading shortwave, along with an associated
sfc cold front boundary, will slowly translate southeast, and
chances of precipitation will follow suit. Any wintry mix that
develops should become all rain during the day Wednesday as the
thermal profile warms, but chances of wintry mix return Wednesday
night as the cold front passes. Total snow accumulation through
Wednesday night is expected to be low - with only up to 1 inch of
accumulation possible, with perhaps slightly higher amounts over
the Minnesota arrowhead region. Temperatures today and Wednesday
will continue to be well above normal, with highs in the mid 40s
into the 50s today, with a cooling trend starting Wednesday, with
highs in the lower 40s north and the lower 50s south.

Long term...(wednesday night through monday)
issued at 352 am CST Tue Feb 21 2017

The surface low center moves to the eastern Great Lakes Wednesday
night. This will bring an end to the precipitation from west to
east. A mix of rain and/or snow will be the main p-type before
changing to all snow late as colder air is pulled into the area
from Canada. High pressure builds in behind the departing system
for Thursday. The models continue to struggle with the system due
to affect the area Thursday night through Friday night. The GFS
has flopped over to yesterdays European model (ecmwf) solution with a farther
northwest track of the surface low, while the latest European model (ecmwf)
solution is now reflecting what the GFS has had for the surface
low location the last few days. The latest run of the Gem is now
leaning toward the European model (ecmwf). Due to this flip flop, will continue to
run with a blend of models. Some snow is expected to affect all
but the International Falls area. The highest snow amounts will be
in northwest Wisconsin with lighter amounts in northeast
Minnesota. With this model variability, will leave out any numbers
for snow amounts for now. The model differences continue on
Saturday and have used a blended approach for pops. An upper level
trof will swing through the region Saturday night with an
attendant cold front. Some snow showers will accompany the front.
Cold air advection behind the front and a northwest wind over Lake
Superior will lead to lake effect snow showers along the higher
terrain of northwest Wisconsin through Sunday night. High pressure
covers the region during this time and lasts into Monday.

&&

Aviation...(for the 18z tafs through 18z Wednesday afternoon)
issued at 1205 PM CST Tue Feb 21 2017

Weak surface ridge over the area this morning has and will cause
most of the stratus and fog to leave the terminals. A period of
VFR conditions can then be expected until a weak shortwave moves
across the Canadian border and brings a period of IFR/LIFR
ceilings and MVFR visiblities with fog and scattered rain showers
beginning around 04z to mainly the northern terminals- kinl,
khib, with better conditions farther south. Lower ceilings may sag
south to affect more terminals after 12z. Have low confidence in
how far south the IFR ceilings will get and when.

&&

Preliminary point temps/pops...
dlh 51 35 45 26 / 0 20 40 40
inl 46 30 39 18 / 20 50 40 10
brd 55 34 48 25 / 0 20 40 40
hyr 55 34 53 29 / 0 10 20 30
asx 54 37 49 29 / 0 10 40 50

&&

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

$$

National Weather Service Glossary of Abbreviations