Scientific Forecaster Discussion

Return to Local Conditions & Forecast

Without Abbreviations
With Abbreviations

Area forecast discussion 
National Weather Service Duluth Minnesota
326 PM CDT Thursday Jul 31 2014

Short term...(this evening through friday)
issued at 326 PM CDT Thursday Jul 31 2014

At 315pm/2015z...there was an upper level low over the
Ontario/Quebec border region. The Northland had light west-northwest to northwest
flow. Temperatures were in the middle 70s to low 80s. The northern
forecast area had clear skies in the much drier flow...while the
SW and southern forecast area had partly cloudy skies in the more
humid flow. There were some showers and weak storms over the south
central forecast area.

This afternoon...there could continue to be isolated to scattered
showers and storms over the southern forecast area. The wind shear
is very weak...but given the 1000 j/kg of mixed layer cape...there
could be brief strong thunderstorms capable of producing small
hail. and relatively clear weather is expected. The very
light wind should allow temperatures to fall to the upper 40s and
lower 50s. There could be brief isolated fog over parts of the
Northland tonight. The model condensation pressure deficits are
not very suggestive of the I left it out of the forecast
at this time. We might need to add it later. The nam12 suggests
that northwest Wisconsin has the best chance of seeing any fog...such as
at khyr...our usual suspect.

Friday...there will be light northerly flow inland...but areas
close to Lake Superior will likely see onshore wind due to a lake
breeze. The models suggest a weak boundary might set up near or
south of the forecast area in northwest Wisconsin. This could be the area
for some shower and storm development. The models suggest there
could be mixed layer cape between 500 to 1000 j/kg but with very
weak wind if any storms develop in this area...there
could be brief strong storms with small hail. The nam12 and sref
are also suggesting the possibility of isolated showers and storms
due to the weak convergence from the lake breeze. High
temperatures should be in the upper 70s and low 80s.

Long term...(friday night through thursday)
issued at 326 PM CDT Thursday Jul 31 2014

The period will start off quiet then become more active as a
frontal boundary across the region becomes a focus for
thunderstorms...some of which could be severe and produce heavy

Friday night into Saturday should be dry across the Northland as a
cold front drops into northern Minnesota Saturday afternoon and
then sags south through the rest of the weekend into early next
week and become nearly stationary. There will be a chance for
showers/storms Saturday afternoon over northern Minnesota as the
front moves in and that area is impacted by a weak upper level

The GFS and European model (ecmwf) seem to be converging on a solution with the 12z
runs. The European model (ecmwf) is a bit further north with the frontal boundary
and the GFS a little further south compared to yesterday at this
time. There will be a chance for showers/storms through much of
the extended period as the front stalls or slowly moves south. We
have probability of precipitation across much of the Northland Sunday through Thursday
with the better chances occurring across the south. An area of
surface low pressure will approach the region Tuesday moving
slowly through into Wednesday night. An upper wave in west-northwest flow
aloft will also accompany the front/low. These features will bring
a better chance for storms into the Northland in the
Tuesday/Wednesday period. A couple rounds of strong to severe
storms will be possible along with heavy rain from early to the
middle part of next week. At this time...the heaviest rain is
forecast to fall just south of the Northland. However...the
location of the frontal boundary is far from certain at this time
and it could shift north and impact more of our region.

Highs Saturday and Sunday will be in the upper seventies to lower
eighties...then cool slightly to the middle to upper seventies for
the remainder of the period.


Aviation...(for the 18z tafs through 18z Friday afternoon)
issued at 1243 PM CDT Thursday Jul 31 2014

Mainly VFR conditions are expected across the Northland through
the period. A cumulus field was once again forming early this
afternoon...and scattered to broken clouds from 5-7kft are
expected for most areas.

There may be a few showers/thunderstorms again this
afternoon/early evening. We confined the mention to khyr which
will have the best chance.

Some patchy fog will be possible late tonight as well...and may
lead to some MVFR/IFR conditions.


Preliminary point temps/pops...
dlh 56 78 56 80 / 10 20 10 10
inl 49 80 52 81 / 10 10 10 30
brd 56 82 58 83 / 20 20 10 10
hyr 53 80 54 81 / 20 30 20 10
asx 52 75 52 78 / 0 10 20 10


Dlh watches/warnings/advisories...


Short term...grochocinski
long term...melde

National Weather Service Glossary of Abbreviations