Area Forecast Discussion
Issued by NWS Duluth, MN

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FXUS63 KDLH 161805 AAB
AFDDLH

Area Forecast Discussion...UPDATED
National Weather Service Duluth MN
1205 PM CST Thu Feb 16 2017

.UPDATE...
Issued at 1206 PM CST Thu Feb 16 2017

Updated for the new 18Z Aviation Discussion below.

&&

.SHORT TERM...(Today through Friday)
Issued at 345 AM CST Thu Feb 16 2017

A ridge of high pressure over the area early this morning is
sliding off to the east as a warm front and trough of low pressure
develops over the eastern Dakotas. Aloft, there is a significant
baroclinic zone developing over Minnesota, oriented in a north-
south fashion. Significant warm air advection is occurring along
this baroclinic zone this morning, and is expected to continue as
the zone slowly shifts east across Minnesota and Wisconsin. As
happened yesterday, the hi-res models are once again picking up
on some potential for snow showers within the baroclinic zone as a
weak ripple moves through the flow. Agreement is a little better
than yesterday, so have gone ahead and included some small POPs
in the forecast for portions of the area during the morning and
early afternoon, though I expect that adjustments will need to be
made as the band has yet to develop upstream. With the warm air
advection going on have gone on the warmer end of guidance, with
most locations getting up into the 30s with only some upper 20s
for the tip of the Arrowhead. The baroclinic zone shifts east of
the forecast area this evening, so feel comfortable going with a
dry forecast overnight tonight, and the warm air should keep our
mins on the mild side. Of concern is the potential for stratus
clouds developing in this warm air advection regime with snow melt
going on to contribute to low level moisture, and the NAM12 has
picked up on this pretty strongly. However, it indicates stratus
should already have formed over eastern North Dakota this morning,
and since it`s not there, this is definitely overdone. Have
instead gone more with the GFS which delays stratus development
until tonight at least, which again may still be too aggressive.
Have kept cloud development minimal for now until we can get a
better handle on the if/when of them. This also leaves us with a
dry forecast and perhaps enough sunshine to boost temperatures
over what we already have in the forecast. For now have gone on
the warm end of guidance for Friday in our south where snow cover
is already pretty low, and have gone more towards consensus where
we should still have a respectable snowpack.

.LONG TERM...(Friday night through Wednesday)
Issued at 345 AM CST Thu Feb 16 2017

The upper level ridge directly over the CWA 00Z Saturday will
push off to the east, as an upper level shortwave slides along the
international border region. Contemplated adding a small chance
of precipitation to the northern quarter of the CWA for Friday
night, but will hold off at this point as it looks as if it would
be very light if anything. The shortwave will move quickly out of
the region early Saturday, allowing heights to build again in the
wake of this shortwave. Will need to watch for the continued
development of stratus and possibly some drizzle or freezing
drizzle late in the week due to warmer temperatures, and melting
snow. Forecast soundings continue to hint at that possibility,
which would impact high temperatures considerably. The development
of a major trough in the western states will result in a sharp
upper level ridge by Sunday, but the trough, and attendant Gulf
moisture will start to affect the Northland already by Monday. The
models are in somewhat better agreement concerning the evolution
of what could be a fairly decent rainfall event from Monday into
Monday night. Will continue with fairly high POP`s across the
area, at least from Monday afternoon through Monday evening. May
even need to consider adding thunder mention at some point,
especially in the south. The upper level flow will generally
flatten in the wake of the Monday and Monday night system, with
dry weather and fairly small chances of precipitation for the rest
of the long term period. High temperatures from Saturday into
Monday are expected to be in the 40s to around 50, with
temperatures settling back into the 30s by next Thursday. The
highs from Saturday to Monday will generally be some 20 degrees
above normal for this time of year.

&&

.AVIATION...(For the 18Z TAFS through 18Z Friday afternoon)
Issued at 1206 PM CST Thu Feb 16 2017

VFR conditions will continue at the terminals through early this
evening, however MVFR CIGS are possible at CKC, ASX, and PBH this
afternoon. An MVFR stratus layer is forecast to develop this
evening as moisture from snowmelt is forced overtop a quasi-
stationary/warm front over western and southern Minnesota.
Ceilings will eventually lower into IFR and eventually LIFR
overnight as the cloud layer deepens. There continues to be a
potential for freezing drizzle across much of northern Minnesota
and northwest Wisconsin. BRD seems to be the exception, with a
shallower cloud layer expected. Did not include a FZDZ in
prevailing groups with this update as there is still some
uncertainty regarding how much moisture will be available. It
seems a majority of the moisture flux in the low-levels is from
snow melt and evaporation, but the models seem to extend the snow
pack farther south than actually exists. Later updates may
introduce FZDZ at some terminals as confidence increases. Overall
confidence in this forecast package is average.

&&

.PRELIMINARY POINT TEMPS/POPS...
DLH  34  26  45  31 /  10   0   0   0
INL  36  26  44  31 /  10   0   0  10
BRD  41  28  53  31 /   0   0   0   0
HYR  36  25  48  30 /  10   0   0   0
ASX  36  26  45  32 /  10   0   0   0

&&

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

$$

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



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