Area Forecast Discussion
Issued by NWS Duluth, MN

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000
FXUS63 KDLH 182346
AFDDLH

Area Forecast Discussion
National Weather Service Duluth MN
646 PM CDT Sat Mar 18 2017

.UPDATE...
Issued at 642 PM CDT Sat Mar 18 2017

Updated aviation section below for 00z TAF set.

&&

.SHORT TERM...(This evening through Sunday)
Issued at 304 PM CDT Sat Mar 18 2017

High pressure was moving into the western half of the forecast area
at 19Z with the wind becoming light. To the east, last remnants of
tight pressure gradient was weakening as the high builds in. Stratus
cloud deck continues to erode with some lingering over the Arrowhead
and northwest Wisconsin. A thin layer of mid clouds was moving into
western Minnesota ahead of a small piece of vorticity in eastern
North Dakota. These clouds may last until sunset then should
dissipate. The surface high will drift over the area tonight. By
daybreak Sunday, all but northwest Wisconsin will be under the
influence of return flow/warm air advection. Coolest min temps will
be over the Arrowhead and northwest Wisconsin, being closest to the
ridge axis.

On Sunday, upper level ridging is over the forecast area in the
morning and moves east in the afternoon. This allows a mid level
trof to move across the region in the afternoon. There are model
differences in the amount of moisture to work with and QPF. Used a
model blend which keeps the forecast area dry in the morning, then
begins to introduce some small chance pops in the afternoon. First
along the St. Croix river valley early in the afternoon where
moisture availability is greatest and first embedded impulse moves
into central Minnesota. Second, have pops from the Arrowhead into
northwest Wisconsin in the late afternoon as the mid level trof
moves farther east. Moisture is still not very deep, but a cold
front is starting its push into the western edge of the area. There
is some marginal MUCAPE at this point, but best forcing is nearer to
the cold front and will leave out the thunder mention. Max temps
will be above normal.

.LONG TERM...(Sunday night through Saturday)
Issued at 304 PM CDT Sat Mar 18 2017

A trough of low pressure and cold front will exit the Northland
Sunday night with some rain showers possible in the evening over
parts of the Northland. High pressure will then build into the
Northern Plains later Sunday night. Most areas will be dry later
Sunday night into Monday night. A shortwave will dive southeast in a
fast west-northwest flow aloft affecting portions of the Northland
Monday night. We have a dry forecast going for now as moisture is
limited.

High pressure will then build south into the region Monday night and
pass through the region Tuesday night into Wednesday. Colder
temperatures will settle over the region with 850mb temperatures to
-11C to to -18c on Tuesday. We have a chance for lake effect snow
showers along portions of the South Shore Tuesday and Tuesday night
but only expect light accumulation due to very dry air and high
pressure at the surface.

Temperatures Monday will be mild with highs in the forties to near
fifty for most areas. Highs Tuesday will drop sharply to the mid
twenties in the Arrowhead to the mid thirties from the Brainerd
Lakes to Pine City to Phillips.

The models still show a significant storm system affecting at least
parts of the Northland Wednesday night into Friday. There are
significant differences in the track of the low with the GFS faster
and much further north versus the ECMWF. The Canadian is closer to
the ECMWF solution. A wintry mix will be possible with the system
but a lot of uncertainty remains due to the significant model
differences.

&&

.AVIATION...(For the 00Z TAFS through 00Z Sunday evening)
Issued at 642 PM CDT Sat Mar 18 2017

VFR conditions across the terminals as of issuance time, which is
expected to continue through the TAF period. Strong southwest
winds aloft should contribute to LLWS at KINL, KHIB, KDLH and
KBRD for several hours between 08z and 16z. After surface winds
increase the LLWS to diminish, with the longest period of LLWS at
KINL and KHIB. South winds to increase to 10-15kts with gusts
approaching 20kts at times until 22z before diminishing.

&&

.PRELIMINARY POINT TEMPS/POPS...
DLH  25  48  29  46 /   0  10  20   0
INL  23  46  26  44 /   0  10  10   0
BRD  29  51  30  50 /   0  10  10   0
HYR  24  50  29  50 /   0  10  20   0
ASX  24  50  30  50 /   0  20  20   0

&&

.DLH WATCHES/WARNINGS/ADVISORIES...
WI...None.
MN...None.
LS...None.
&&

$$

UPDATE...LE
SHORT TERM...GSF
LONG TERM...Melde
AVIATION...LE



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