Area Forecast Discussion
Issued by NWS Duluth, MN

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FXUS63 KDLH 282342
AFDDLH

Area Forecast Discussion
National Weather Service Duluth MN
642 PM CDT TUE JUN 28 2016

.SHORT TERM...(This evening through Wednesday)
Issued at 402 PM CDT Tue Jun 28 2016

Warming trend into Wednesday as a cold front approaches from the
north resulting in increasing clouds and a chance for showers and
storms.

On the synoptic scale the northwest flow pattern across the northern
Plains and upper Midwest will continue through mid-week due to a
ridge over the Rockies and a longwave trough over Appalachia. A cold
front will approach from the north Wednesday, but not before warmer
air can advect in from the west ahead of the front result in a
slightly warmer day. Upstream observations in Canada show some
locations around 80, and this certainty seems plausible for parts
of northern Minnesota. Winds will also be breezy especially along
the international border just ahead of the cold front, out of the
west-southwest at 5-10mph with gusts to 15-20mph due to deep mixing.

Isolated to scattered thunderstorms are expected Wednesday afternoon
along and ahead of the cold front approaching from the north. With a
deeply-mixed inverted-V-looking sounding gusty winds are possible
with any storms. With only 15-20kts of speed shear through the 0-6km
layer do not expect much organization with these storms, though
towards the late afternoon some guidance suggests upwards of 1000
j/kg MLCAPE develop which could result in some heavy downpours.

.LONG TERM...(Wednesday night through Tuesday)
Issued at 402 PM CDT Tue Jun 28 2016

Main concerns with this forecast package are thunderstorm chances
Wednesday night and Thursday, and again during the holiday weekend.

Low pressure at the surface and aloft will be centered over far
northern Ontario Wednesday evening, with a cool front poised just
north of the International Border. The front will advance southeast
across much of northern Minnesota overnight and through northwest
Wisconsin Thursday morning. Along and ahead of the front, showers and
thunderstorms are expected. Diurnal instability will likely linger
into late evening keeping a few thunderstorms around. Of course,
there is a small possibility a few isolated thunderstorms may persist
all night. Severe weather is not anticipated at this time. However,
the most vigorous storms will produce frequent lightning, brief heavy
rainfall, small hail, and wind gusts to around 40 mph.

The upper trough will slowly rotate farther eastward Thursday
afternoon through Sunday morning while a surface ridge of high
pressure drifts across the western Great Lakes. Fairly quiet
conditions are expected in the wake of the front through the first
half of the weekend. A subtle shortwave trough and associated vort
max may generate a few showers or a thunderstorm over my western
zones on Saturday, but guidance is split with only the GFS carrying
much of a risk. Opted for low chance POPs until Saturday evening.

Increasing southwesterly flow behind the departing ridge will push a
warm front northward into Minnesota Saturday night and Sunday. A few
storms are possible Saturday night near the warm front and on the
nose of the low level jet. The front is forecast to stretch from
near Winnipeg to near Duluth to Green Bay by late Sunday afternoon.
Another compact shortwave trough will dive southeast across the
Northland Sunday evening, which should support showers and
thunderstorms.

The frontal boundary is expected to linger near the Northland
through Monday into early Tuesday with several more rounds of
thunderstorms possible, especially Monday night.

Shear and instability parameters for this weekend into early next
week seem somewhat subdued for early July. Think there is a
potential for a few strong thunderstorms, at least, from Saturday
night through Tuesday morning.

Temperatures through the period will trend near to slightly below
seasonal averages. Look for highs in the upper 60s Thursday then
warming into the 70s to low 80s for the remainder of the period.
Lows are expected to range from the upper 40s to low 60s.

&&

.AVIATION...(For the 00Z TAFS through 00Z Wednesday evening)
Issued at 642 PM CDT Tue Jun 28 2016

VFR conditions expected through much of the forecast cycle. There
is a possibility of radiational fog to develop late tonight due
to light winds and clear skies. This is due to high pressure
building over the region. Used the NAM/RAP/HRRR to try and best
determine where radiation fog is most likely, but still uncertain
on how widespread fog coverage will be. At the moment kept
visibility in the MVFR range, but lower visibility is possible for
brief periods.

A cold front will move southward into northern Minnesota late
Wednesday afternoon. Ahead of the front rain showers and
thunderstorms are possible. Uncertain how widespread thunderstorm
activity will be during the afternoon, but felt most confident to
include as VCTS at KINL. Left as VCSH at KDLH/KHIB until the end
of the current forecast.

&&

.PRELIMINARY POINT TEMPS/POPS...
DLH  51  77  59  69 /   0  30  40  50
INL  51  77  56  66 /  20  60  40  20
BRD  52  79  59  73 /   0  20  40  40
HYR  47  77  58  71 /   0  10  40  60
ASX  48  78  59  68 /   0  20  40  60

&&

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

$$

SHORT TERM...JJM
LONG TERM...Huyck
AVIATION...WL



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