Area Forecast Discussion
Issued by NWS Duluth, MN

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FXUS63 KDLH 241142
AFDDLH

Area Forecast Discussion
National Weather Service Duluth MN
642 AM CDT Thu May 24 2018

.UPDATE...
Issued at 630 AM CDT Thu May 24 2018

Updated for the 12z Aviation Discussion below.

&&

.SHORT TERM...(Today through Friday)
Issued at 419 AM CDT Thu May 24 2018

An area of thunderstorms, some strong, continued early this
morning over far northwest Wisconsin into all but far northeast
Minnesota. A low level jet around 40 knots, per area 88D`s, was
aiding in driving continued thunderstorm development this morning.
The warm front was located over portions of west central into
southeast Minnesota early this morning and is forecast to move
northeast through much of the Northland by this evening. We expect
a gradual east to northeast movement to the showers/storms this
morning and expect them to diminish mid-late morning as the low
level jet weakens. The showers/storms may not end everywhere
altogether, but coverage should wane through the mid-late morning
hours. Coverage should again increase this afternoon and evening,
mainly over parts of northern Minnesota. As the low level jet
increases tonight, thunderstorm coverage should again expand. The
models are in decent agreement shifting the low level jet east
later tonight into far eastern Minnesota/northwest Wisconsin and
we have highest chances there from late evening and overnight.
Some storms could be severe later this afternoon and tonight and a
large pool of CAPE will exist over and south of the area. Plenty
of moisture will also be in place with Pwat values around 1.5".
GOES-16 was showing Pwat values already around 1.4". Shear
continues to be marginal with consensus around 25 to 30 knots of
deep layer shear but there could be a period where the shear
increases a bit as a shortwave moves through northern Minnesota
later tonight.

There will be a continued chance for showers and thunderstorms
Friday as the upper trough move through along with a cold front. A
few strong to severe storms will be possible over northwest
Wisconsin and adjacent areas of Minnesota.

Today will be warm with highs in the mid eighties for most areas.
Areas around Lake Superior will be cooler with onshore flow. Highs
Friday will be in the lower to middle eighties, and even lakeside
locations should warm as winds shift to west to southwest.

.LONG TERM...(Friday night through Wednesday)
Issued at 419 AM CDT Thu May 24 2018

The extended forecast period continues to highlight some chances of
showers and thunderstorms, with temperatures that are well above
seasonal averages through mid-week next week.

Friday night and Saturday morning will feature a mid-level shortwave
trough that will slowly advance southeastward across the northern
sections of the forecast area, which will support chances of showers
and storms during that time frame. Most-unstable CAPE will diminish
rapidly Friday evening, with values starting around 2000 J/kg at
00z, falling to around 500 to 1000 J/kg at midnight Saturday. Deep
layer shear continues to be a limiting factor, with values around 20
to 30 knots per the GFS/NAM/ECMWF models, although some better shear
will be possible over north-central Minnesota where a low-level jet
should develop at this time. Severe weather is not anticipated at
this time.

Sunday is looking dry and mostly sunny as mid-level ridging briefly
takes control over the region. High temperatures expected to rise to
the 80s over much of the region, with upper 80s possible over our
southern tier of counties. Then, a longwave mid-level trough will
eventually translate from the Intermountain West states into the
Upper Mississippi River Valley region, bringing more prolonged
chances of showers and thunderstorms Monday through Thursday.
Forcing will be generally weak, per the Thaler QG omega progs, but
moisture will be a big question as the GFS soundings don`t show much
in terms of deep saturation through Monday. Both the GFS and ECMWF
models are in pretty good agreement with bringing some better
chances of showers and storms Tuesday through Thursday. Some decent
instability could be in place during this time frame. High
temperatures continue to be in the upper 70s and into the 80s
through Wednesday next week.

&&

.AVIATION...(For the 12Z TAFS through 12Z Friday morning)
Issued at 642 AM CDT Thu May 24 2018

A large area of showers and thunderstorms will persist through
much of the morning as a warm front moves through the region from
the south. Some MVFR to LIFR conditions were observed due to the
heavy rainfall and thunderstorm activity this morning. Eventually,
this activity will shift to the northeast away from the TAF
terminals, but another round of showers and storms are expected
this afternoon and evening as a cold front moves into the region.
The most likely timing for this second round looks to be after 3
PM this afternoon.

There should be a small window overnight of low-level wind shear
at KDLH due to a strengthening low-level jet. This is also
possible at KHIB, but confidence was too low to place in the KHIB
TAF at this time.

&&

.PRELIMINARY POINT TEMPS/POPS...
DLH  82  59  84  58 /  70  50  30  20
INL  87  61  83  55 /  60  40  40  30
BRD  87  62  86  59 /  50  50  10  10
HYR  88  64  85  59 /  60  60  40  30
ASX  87  62  85  55 /  70  50  40  30

&&

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

$$

UPDATE...JTS
SHORT TERM...Melde
LONG TERM...JTS
AVIATION...JTS


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