National Weather Service Weather Forecast Office

• Home
• Site Map
• News
• Organization
• Search for: NWS All NOAA 

000
FXUS63 KDLH 200909
AFDDLH

Area Forecast Discussion
National Weather Service Duluth MN
409 AM CDT Sat May 20 2017

.SHORT TERM...(Today through Sunday)
Issued at 409 AM CDT Sat May 20 2017

Cloud cover had spread northward across much of the Northland
early this morning. A closed upper low was located over the
Rockies and the western Great Plains with a surface low centered
over northeast Kansas. Poleward moisture transport ahead of the
trough and surface low will increase precipitable water values
across the Upper Midwest to between 0.50 and 1.25 inches by this
afternoon. Rain will spread northward across the forecast area
later this morning and this afternoon, continuing overnight.
Widespread rainfall of up to one inch is expected, with locally
higher amounts possible in northwest Wisconsin. The dry slot is
forecast to lift into northern Wisconsin overnight. Mid-level
lapse rates are expected to steepen slightly and should yield a
marginal ribbon of up to 250 J/kg of MUCAPE. Have added a slight
chance of thunderstorms for interior portions of northwest
Wisconsin tonight. Severe weather is not anticipated, with pea-
size hail possible from the strongest storms.

The trough and surface low will lift northeastward through the
Upper Midwest on Sunday. Cold air advection aloft should continue
the rain chances for the second half of the weekend, but changing
to a more showery rather than stratiform structure. Additional
rain amounts should be lower, up to one-quarter inch.

.LONG TERM...(Sunday night through Friday)
Issued at 409 AM CDT Sat May 20 2017

An upper level low will be over the region Sunday evening, moving
slowly east through Tuesday. Several shortwaves will rotate
around the low and there will be a chance for showers Sunday night
through Tuesday.

The best chance for showers through midweek will be Sunday night
into Monday. We have the highest chances during that time over far
northern Minnesota. Widespread heavy rainfall is not expected.
Highs Monday will range around 50 to 55 in the Arrowhead to around
60 south.

The low will continue east Monday night into Tuesday with the
upper flow becoming more northerly. A chance for showers will
continue and there is some concern coverage may be higher than our
current probabilities. If the models look similar with the next
update, POPS will be increased. Widespread heavy rain again looks
unlikely. Highs Tuesday will be in the lower fifties to lower
sixties.

Upper ridging will exist to the west Tuesday night moving over
the region Wednesday into Wednesday night. A dry period will occur
Tuesday night through Wednesday night with ridging in place.
Temperatures will warm into the sixties but be cooler around Lake
Superior.

Although there are timing and strength issues with the pattern
late in the week into next weekend between the GFS and ECMWF, they
both do develop a western CONUS trough. Southerly flow will
develop over the region Thursday with a low pressure system moving
through late in the week into the weekend. Depending on the speed
of the low, significant rainfall could occur as instability
increases. Highs Thursday through Saturday will be mainly in the
sixties.

&&

.AVIATION...(For the 06Z TAFS through 06Z Saturday night)
Issued at 100 AM CDT Sat May 20 2017

Low pressure will move northeastward from the Central Plains
tonight, into the Upper Mississippi River Valley by Saturday
evening. Expect gusty winds to be a concern beginning mid Saturday
morning as the pressure gradient tightens due to the incoming low
and high pressure building over western Quebec. Precipitation will
gradually spread in from south to north Saturday afternoon. As the
lower levels moisten, expect ceilings to gradually lower from VFR
eventually to IFR/LIFR with a potential for VLIFR per the
NAM/GFS/RAP and DLHWRF. In addition, expect visibility reduction
as heavier precipitation is moving in. A bit uncertain at this
point how low visibilities will get at DLH as the easterly winds
will bring the marine air inland. Suspect the current TAF may not
be low enough based on past experience.


&&

.PRELIMINARY POINT TEMPS/POPS...
DLH  46  37  48  40 /  90 100  60  40
INL  58  39  48  40 /  50  80  70  50
BRD  48  40  50  41 / 100  90  60  30
HYR  52  44  52  41 / 100  90  60  50
ASX  48  39  51  41 /  90  90  60  40

&&

.DLH WATCHES/WARNINGS/ADVISORIES...
WI...None.
MN...None.
LS...Small Craft Advisory from 10 AM this morning to 10 AM CDT Sunday
     for LSZ121-140>143-146>148.

     Small Craft Advisory until 4 PM CDT this afternoon for LSZ144-
     145.

     Small Craft Advisory from midnight tonight to 10 AM CDT Sunday
     for LSZ144-145.

     Gale Warning from 4 PM this afternoon to midnight CDT tonight
     for LSZ144-145.

&&

$$

SHORT TERM...Huyck
LONG TERM...Melde
AVIATION...WL