Area Forecast Discussion
Issued by NWS Duluth, MN

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FXUS63 KDLH 281133

Area Forecast Discussion
National Weather Service Duluth MN
633 AM CDT Fri Apr 28 2017

Issued at 633 AM CDT Fri Apr 28 2017

Please see the 12z Aviation Discussion below.


.SHORT TERM...(Today through Saturday)
Issued at 331 AM CDT Fri Apr 28 2017

Quieter weather expected today, with the strong low from the past
2 days now well off over eastern Ontario, and only lingering
cyclonic flow to keep mostly cloudy skies and some snow showers
going during the day today. The steep low level lapse rates will
be enhanced by some weak shortwaves to aid the snow shower
development. Have kept pops pretty low as confidence in coverage
and placement is pretty low. The clouds will keep temperatures on
the cool side once again, with highs only in the mid 30s to mid
40s. Tonight a clearing trend can be expected, with the main
question being timing, which in turn affects how cold we will get.
Have nudged temperatures down somewhat, getting into the teens to
low 20s over much of the Arrowhead. Saturday temperatures finally
begin recovering back towards normal values, but will still be 5
to 10 degrees below normals for this time of year. Sunshine will
favor warmer temperatures, but the north flow and lingering cold
air advection are less favorable. Highs should get into the mid
30s to mid 40s.

.LONG TERM...(Saturday night through Thursday)
Issued at 331 AM CDT Fri Apr 28 2017

Saturday night and much of Sunday morning will be dry across the
Northland, thanks to some remaining low-amplitude mid-level ridging.
However, clouds will be on the increase ahead of a potentially
significant storm system that is slated to advance through the
region Sunday afternoon through Tuesday morning.

This system will be supported by a large mid- to upper-level
longwave trough, which will bring deep lifting with it, as indicated
by progged upper-level divergence and mid-level isentropic upglide.
The associated sfc low pressure center will track from the OK/AR
region early Sunday morning, towards the central and northern
portions of Wisconsin by Monday evening. Moisture appears to have
increased from previous model runs, with Pwat values over Price and
Sawyer counties over 1 inch, according to the 28.00z GFS. The
overall consensus of the synoptic models is to lift the
precipitation shield north by Sunday afternoon as the inverted
trough of the sfc low moves overhead, with the heaviest
precipitation being Monday morning and into the afternoon. The
cyclonic circulation around the sfc low will help to bring
northeasterly winds over the region, which will be favorable for
stronger gusts, especially along adjacent locations of Lake
Superior. The 28.00z GFS/NAM model soundings continue to indicate
that the primary precipitation types associated with this system
will be a rain/snow mixture. However, some freezing rain or sleet
can`t be ruled out at this point, especially Sunday night and Monday
morning. Guidance is starting to lock onto snow accumulation
amounts, but there is still much uncertainty with these amounts, so
it`s a bit too early to mention specific snow amounts. However,
several inches of accumulation will be possible. At this time, the
SREF ensemble snow probabilities are indicating the corridor of the
most likely snow accumulation will be from the Brainerd Lakes area,
northeast towards the Iron Range. Moreover, the heaviest QPF amounts
are expected to fall Monday morning, which will make for a messy
Monday morning commute. Those with travel plans for late Sunday and
Monday will want to stay tuned for future updates. Chances of
precipitation with this system will linger over the western Lake
Superior area through Tuesday morning as the sfc low pressure center
lifts northeast.

Beyond Tuesday, the weather looks to dry up through Wednesday as
subtle mid-level ridging moves overhead. The GFS/ECMWF/CMC models
appear to disagree with possible chances of precipitation for
Wednesday, so just leaned towards the consensus blends POPs for now.
Temperatures look to rebound through the rest of the week as sfc
high pressure develops over Ontario Canada, and brings in some warm
air advection on southerly return flow.


.AVIATION...(For the 12Z TAFS through 12Z Saturday morning)
Issued at 633 AM CDT Fri Apr 28 2017

An area of low pressure continues to advance to the northeast over
Hudson Bay, which will keep the Northland under its cyclonic flow
and mainly MVFR ceilings and visibilities. Radar shows some
returns from light snow showers that have developed due to the
cyclonic flow, but confidence in how long they will last and what
impact they will have on visibilities is low. However, these
showers should diminish through the morning hours. Current GOES-16
satellite imagery does show some clearing to our southwest as the
low pressure lifts away from the region, so locations near KBRD
and KHYR may see more scattered cloud cover, with highest
confidence of this over KBRD.

Boundary layer mixing of up to 850-800 mb today will help to lift
ceiling heights into VFR categories this afternoon, but will also
help mix down some stronger wind gusts, with gusts up to 15 to 20
knots possible.


DLH  43  26  48  30 /  10   0   0  10
INL  41  20  53  28 /  20   0   0   0
BRD  46  25  54  32 /   0   0   0  10
HYR  46  24  51  32 /   0   0   0  10
ASX  44  26  47  29 /  10  10   0  10




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