Area Forecast Discussion
Issued by NWS Duluth, MN

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FXUS63 KDLH 290148
AFDDLH

Area Forecast Discussion
National Weather Service Duluth MN
848 PM CDT SAT MAY 28 2016

.UPDATE...
Issued at 848 PM CDT Sat May 28 2016

Added fog to much of the forecast area for the rest of the night
as winds have diminished and fog is already forming. Removed
thunderstorm mention from counties on the west side of the
stationary front that is draped over north central Wisconsin. The
front was roughly between Park Falls and Phillips. This is also
where the best instability remains with MUCAPE greater than 500
J/kg and effective bulk shear of 35 knots.

UPDATE Issued at 550 PM CDT Sat May 28 2016

A stable airmass is covering northeast Minnesota. Have removed the
mention of thunder from northeast Minnesota for the rest of today
and this evening. With a frontal boundary draped over north
central Wisconsin, will see showers with scattered thunderstorms
through the evening. Adjusted the sky a bit over Price county
where the sun has emerged. Made some other minor tweaks.

&&

.SHORT TERM...(This evening through Sunday)
Issued at 317 PM CDT Sat May 28 2016

A somewhat stacked area of low pressure over the Northern Plains
will lift from the South Dakota and Iowa border region, as of this
afternoon, to western Lake Superior by later tonight. The low
brought a surge of moisture into the Northland, and scattered
showers are expected to continue through tonight and Sunday
morning as the low lifts through the region. The heaviest rains
will likely occur across parts of northwest Wisconsin through this
evening. The threat of thunder across the Northland is fairly low,
with the exception of areas of northwest Wisconsin well inland of
Lake Superior, where instability and deep layer wind shear could
be just enough to produce isolated strong cells capable of
smallish hail. Otherwise, the main concern for the storms is brief
heavy rain because of the abundant moisture, with precipitable
water values around 1.3 inches in the southeast forecast area.
Leaned on the modeled most unstable cape in the GFS, RAP, and SREF
for the thunder threat, which limits thunder to primarily the
southeast forecast area. However, included isolated storms for a
stretch of northeast Minnesota to account for the NAM, which has a
ribbon of cape developing for inland areas from Lake Superior.
This scenario seems fairly unlikely, though, given the poor
heating from the extensive cloud cover.

Fog will continue to be possible near Lake Superior, and inland
around the Twin Ports, through Sunday morning. Overnight lows
should range from the upper 40s near Lake Superior to the low to
middle 50s inland.

There should be some clearing across the western and southern
forecast area Sunday morning in the wake of the passing low, but
showers will still be likely across the Arrowhead and northwest
Wisconsin. The clearing, though, will lead to better heating, and
isolated to scattered showers and storms could develop across the
western and southern forecast area in the afternoon in the west-
northwest flow. The models are not in good agreement concerning
the pcpn, so leaned on the SREF to blend out the noise.

It may take some time to heat up Sunday because of the morning
cloud cover and humidity, but once areas begin to dry up later in
the morning, temperatures should build to the upper 60s and lower
70s by the late afternoon or early evening. Concerned the forecast
for the inland Arrowhead may be too optimistic because of the
cloud cover. May need to lower to the low 60s for next forecast.

.LONG TERM...(Sunday night through Saturday)
Issued at 317 PM CDT Sat May 28 2016

Surface high pressure and mid level ridging buildS over the forecast
Sunday night and Monday. The dry period will be short lived as a
low pressure center Translates across the Dakotas, lifting a warm
front into the region through the day tuesday. Have adjusted
timing of pops Tuesday as latest guidance is trending slower with
onset of precipitation as the advancing moisture will be in battle
with the dry easterly flow.

Focus turns to the stacked low and associated cold front that will
track across Minnesota and over Lake Superior during the
Wednesday/Wednesday night periods. The low will trigger showers and
thunderstorms with a potential for periods of heavy rain. A brief
period of cooler conditions with highs in the 50s and 60s will
follow the low passage on Thursday.

&&

.AVIATION...(For the 00Z TAFS through 00Z Sunday evening)
Issued at 706 PM CDT Sat May 28 2016

IFR/LIFR cigs/visby expected through the overnight due to light
winds and saturated air. Scattered showers and drizzle will
continue across much of the region overnight...with thunderstorms
possible over the next few hours at KHYR as MUCAPE is around 500
J/kg per the 23Z SPC mesoanalysis. Expecting lowest visby at
KDLH/KINL overnight...with 1/4sm visby at KDLH later tonight.

Winds will switch to a northwesterly direction as an area of low
pressure moves into southwestern Ontario. This will gradually
improve conditions to MVFR/VFR between 15 to 21z.


&&

.PRELIMINARY POINT TEMPS/POPS...
DLH  51  72  51  76 /  50  60  10   0
INL  53  69  49  75 /  50  40  10   0
BRD  55  76  52  80 /  60  40  10  10
HYR  56  74  51  79 /  60  50  10   0
ASX  50  71  51  76 /  50  50  10   0

&&

.DLH Watches/Warnings/Advisories...
WI...None.
MN...None.
LS...None.
&&

$$

UPDATE...GSF
SHORT TERM...Grochocinski
LONG TERM...Graning
AVIATION...WL


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