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Area forecast discussion 
National Weather Service Duluth Minnesota
619 PM CDT Tuesday Oct 13 2015

Short term...(this evening through wednesday)
issued at 319 PM CDT Tuesday Oct 13 2015

The focus of this forecast is on cloud cover through this evening.
Cloud cover appears to be following the namnest and rap13 models
the leaned on those models. Most of the forecast area
should be clear by late this evening.

The Northland will continue to see clearing skies into this
evening higher pressure and drier air move into the region. Light
winds will develop overnight. The combination of the clear skies
and light wind speeds will promote radiational cooling. Leaned on
the colder bias corrected GFS/Gem regional models in my
weighting. Overnight lows should range from the low to upper 30s
for most areas. There will be a low probability of fog. The
probability seemed high enough for parts of northwest Wisconsin to add
patchy fog late tonight.

The cool west-northwest/northwest flow pattern will continue Wednesday...but
temperatures will be warmer because of the sunny skies. Leaned on
the warmer bias corrected GFS/GFS MOS guidance. Highs should
range from the middle 50s over The Arrowhead to the lower 60s
across the southern forecast area.

Long term...(wednesday night through tuesday)
issued at 319 PM CDT Tuesday Oct 13 2015

The forecast area will remain under a zonal/northwest flow through the
rest of the week...allowing a series of short waves dive south
from Canada and pass over the region. Latest guidance shows the
first wave/thermal trough drops into North Dakota/Borderland by
12z Thursday...sweeping over the Northland through the day. The
associated cold air advection will bring gusty northwest winds...falling well as chances for rain/snow showers Thursday
afternoon/Thursday night. Guidance is in good agreement 850 mb temperatures
Thursday morning begin in the single digits...falling below
freezing across the Borderland through the afternoon. Readings
approaching negative 30c at h50 will provide enough instability to
trigger showers as the cold Canadian airmass builds into the
region through Thursday evening. Latest GFS bufr soundings suggest
enough cape in the freezing layer to support a brief wintry mix of
light rain/snow/graupel...mainly across the Iron Range and
arrowhead regions. Little or no accumulation is expected at this

Focus turns to lake effect snow potential for locations along the
South Shore of Lake Superior late this week. The cold air mass and
northwest trajectories will favor les development across the elevated
terrain of mainly Ashland and Iron counties. At this time the best
chance for any les will be Thursday night into Friday morning as 850 mb
temperatures on the order of -10c drift over Western Lake Superior.
Snowfall amounts are difficult to quantify at this time but an
inch or more is possible in areas favored for les and terrain

The latest forecast models are in good agreement for late this week
heading into next week. GFS and European model (ecmwf) show an amplified pattern
at h25 and h50 late this week...before transitioning to a zonal
pattern for the second half of the weekend...into next week. High
pressure will build in from central Canada on Saturday...and shift
eastwards throughout the day. As a result will see a shift from cold
air advection to warm air advection as the ridge axis slides
overhead. With the high building in quiet weather is expected through
the weekend...with a warming trend on Sunday heading into next week.
A trough will move in from the northern plains on
Monday/Tuesday...this will bring some light rain showers.


Aviation...(for the 00z tafs through 00z Wednesday evening)
issued at 619 PM CDT Tuesday Oct 13 2015

High pressure will build over the terminals through the forecast
period. VFR is expected.


Preliminary point temps/pops...
dlh 40 60 36 52 / 0 0 0 20
inl 35 58 34 49 / 0 0 10 40
brd 39 64 37 54 / 0 0 0 10
hyr 33 63 35 55 / 0 0 0 20
asx 34 63 35 55 / 0 0 0 30


Dlh watches/warnings/advisories...


Short term...grochocinski
long term...graning

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