Area Forecast Discussion
Issued by NWS Duluth, MN

Home | Current Version | Previous Version | Graphics & Text | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47
000
FXUS63 KDLH 210557
AFDDLH

Area Forecast Discussion
National Weather Service Duluth MN
1257 AM CDT Fri Apr 21 2017

.UPDATE...
Issued at 1257 AM CDT Fri Apr 21 2017

Please see the 06Z Aviation Discussion below.

&&

.SHORT TERM...(This evening through Friday)
Issued at 333 PM CDT Thu Apr 20 2017

Rain and snow across the Northland will gradually diminish from
the west through this evening as an area of low pressure moves
through the Great Lakes region. The associated upper-level low,
which is causing widespread synoptic lift to drive the rain and
snow, will move from its current location near Bayfield Peninsula,
to the Keweenaw Peninsula by early this evening, so the synoptic
lift will shift east soon. The areas most likely to see snow are
along and near the higher terrain of the North Shore, including
from the higher terrain of Duluth up to the far North Shore. Most
areas should get little if any additional snow accumulation
because of melting or lack of falling snow.

There will be clearing skies from the north and west overnight
into Friday as the low exits to the east, while high pressure will
build into the region. Mostly clear skies and very light wind
speeds will develop by late tonight. Considering today`s humidity
and precipitation, patchy fog is possible across much of the
Northland early Friday.

The high pressure will provide a sunny and dry day for the
Northland. Highs should reach the middle 50s to low 60s, with this
forecast being slightly warmer than the previous forecast. The
coolest areas will be near the Lake Superior shoreline because of
a weak lake breeze.

.LONG TERM...(Friday night through Thursday)
Issued at 333 PM CDT Thu Apr 20 2017

The long-term forecast will be highlighted by some chances of
light precipitation, with some snow possible, and some slightly
cooler than normal temperatures.

Friday night and Saturday morning look dry at this point due to
high pressure in control over the region. However, chances of rain
showers will increase through the afternoon and evening as a cold
front boundary draped along an area of low pressure dives
southward. Resulting rainfall amounts should be light with this
boundary. Some snow may mix in with the rain Saturday evening and
into Sunday morning. Saturday looks to be the warmest day of the
long-term period, thanks to northwesterly winds keeping the cooler
temperatures over Lake Superior at bay. Highs Saturday should
range from the upper 50s north to the lower 60s south.

The baroclinic zone associated with this cold front boundary will
actually pivot northeastward due to increased 850 mb winds as the
low-level jet strengthens. Warm air advection will become
enhanced as evident by the 850-700 mean layer warm air advection
in the latest model guidance. Precipitation chances will linger
due to this warm front aloft, which will persist through the day
Monday as a mid- level shortwave trough moves into the region,
reinforcing the warm air advection. The best chances of
precipitation will be over the northern one-half of forecast area
since that is where the strongest isentropic upglide will
coincide. Some snow could once again mix in with rain showers.

Another mid-level wave could bring another shot of precipitation,
especially over northwest Wisconsin, for Wednesday morning
through Thursday. However, there is some uncertainty between the
GFS/ECMWF/CMC models. The ECMWF model appears to be the driest at
this time, with the GFS as the quickest model, and the CMC model
has the highest QPF amounts. Due to the uncertainty during this
time period, I leaned toward the consensus blends for the POPs.
Temperatures for Monday through Thursday don`t really change much
at all, with some cooler temperatures along Lake Superior due to
east to northeasterly on-shore flow. High temperatures for this
period will range from the lower to mid 40s north to the upper 40s
and lower 50s south.

&&

.AVIATION...(For the 06Z TAFS through 06Z Friday night)
Issued at 1257 AM CDT Fri Apr 21 2017

High pressure will build into the region from the Northern Plains
tonight through Friday. This will keep mostly clear skies across
much of northeast Minnesota tonight with light winds. This
combined with recent precipitation, has resulted in radiation fog
development. Expect fog to persist across northeast Minnesota into
the morning hours. Will see visibilities range anywhere from VLIFR
to VFR as is typically the case with radiation fog. Fog may
develop at KHYR if skies clear. Currently think that MVFR/IFR
cloud cover will remain in place KHYR until early Friday morning,
which will limit the amount of radiational cooling. So, for now
held off on mentioning fog at KHYR.

Will see a return to VFR conditions around 14Z to 15Z once fog
dissipates with light winds through the rest of the forecast.

&&

.PRELIMINARY POINT TEMPS/POPS...
DLH  31  55  35  61 /  40   0   0  10
INL  32  61  36  55 /  10   0   0  30
BRD  33  60  36  64 /   0   0   0   0
HYR  32  57  31  63 /  30   0   0   0
ASX  32  54  32  65 /  70   0   0   0

&&

.DLH WATCHES/WARNINGS/ADVISORIES...
WI...None.
MN...None.
LS...Small Craft Advisory until 1 AM CDT early this morning for
     LSZ145-146.

     Small Craft Advisory until 9 AM CDT this morning for LSZ121-
     140>144-147-148.

&&

$$

UPDATE...WL
SHORT TERM...Grochocinski
LONG TERM...JTS
AVIATION...WL



USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.