Area Forecast Discussion
Issued by NWS Duluth, MN

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FXUS63 KDLH 292359
AFDDLH

Area Forecast Discussion
National Weather Service Duluth MN
659 PM CDT Mon May 29 2017

.UPDATE...
Issued at 650 PM CDT Mon May 29 2017

See updated aviation section below. Am also working on an update
for the latest radar trends.

&&

.SHORT TERM...(This evening through Tuesday)
Issued at 330 PM CDT Mon May 29 2017

Cutoff low pressure aloft will loiter over the Great Lakes
through the short term period. Intermittent rain showers will
continue, with a few rumbles of thunder possible. Expect the
coverage and intensity of the showers to diminish this evening
with the loss of heating, but clouds will linger. Breezy northwest
winds will persist through this evening before diminishing as the
boundary layer decouples. Temperatures tonight will bottom out in
the upper 30s to middle 40s.

Another uptick in shower coverage is expected late tonight as a
lobe of vorticity rotates southeastward through southern Manitoba
and into northern Minnesota. Rain showers continue off and on
through Tuesday afternoon as increasing sunshine generates enough
instability to fill the gaps with new showers. A few rumbles of
thunder are in the cards once again, mainly in the Minnesota
Arrowhead and over northwest Wisconsin. Temperatures will climb
into the low 50s north to the upper 50s south. Depending on where
the holes in the clouds develop, some spots may jump into the low
60s, especially from the Brainerd Lakes through Hayward and into
the Park Falls area. Confidence in the timing and location of
those breaks is low, so kept a consensus approach to temperatures.

.LONG TERM...(Tuesday night through Monday)
Issued at 330 PM CDT Mon May 29 2017

The last upper level long wave trof works its way across the
forecast area Tuesday night. This means some POPs in the evening,
ending overnight as the trof departs. Surface ridging builds into
the area Wednesday through Thursday. The GFS, and to a lesser
extent, the ECMWF, have some QPF along the south shore of Lake
Superior Thursday night. The GEM is dry. This is in response to a
channeled area of vorticity moving over the Arrowhead. Used a
consensus approach to POPs which favors low POPs along the south
shore in the evening. Friday into Friday evening features the
return of the surface ridge. Model differences become large late
Friday night through Sunday. The GFS is mainly dry, but brings in
some QPF Saturday night through Sunday as a sharp east to west
short wave trof drops south through the area. The ECMWF has a more
elongated trof initially Friday night, but develops a closed low
by 12Z Sunday right over Duluth. The GEM develops a deep cut off
low over southern Minnesota at this time. Used a blend to account
for these differences.

&&

.AVIATION...(For the 00Z TAFS through 00Z Tuesday evening)
Issued at 650 PM CDT Mon May 29 2017

Cyclonic flow both at the surface and aloft in with some weak
ripples in the flow will keep showers in the forecast for the
terminals through much of the upcoming period. A fresh surge of
colder air will bring another wave of MVFR or possibly even IFR
ceilings into the terminals again after 04z this evening,
continuing until approximately 17z before rising again. Some
guidance has widespread IFR conditions, but have kept to MVFR as
it appears the IFR ceilings are likely only with showers and will
have to wait and see on the timing and placement of these before
including in the terminals, and have left out for now. A few
locations may return to VFR after 21z or at least trend that
direction.

&&

.PRELIMINARY POINT TEMPS/POPS...
DLH  43  53  42  69 /  30  40  20   0
INL  43  54  41  70 /  50  60  20   0
BRD  45  56  43  71 /  30  30  10   0
HYR  46  55  42  69 /  40  40  20   0
ASX  46  55  43  68 /  40  50  30   0

&&

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

$$

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



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