Tornado Warning 10, NWS Duluth, MN

Area Forecast Discussion
National Weather Service Duluth MN
653 PM CDT Wed Jul 17 2019

.UPDATE...
Issued at 653 PM CDT Wed Jul 17 2019

Updated for the 00Z aviation discussion.

&&

.SHORT TERM...(This evening through Thursday)
Issued at 416 PM CDT Wed Jul 17 2019

Two rounds of showers and storms today, with a low threat for severe
storms and a conditional threat for heavy rain/flash flooding. Hot
and humid again on Thursday with a low chance for a few isolated
storms.

On the synoptic scale a mid/upper level shortwave ridge is over the
Upper Midwest and Upper Great Lakes while a weak mid/upper level
shortwave moves across central Manitoba with at least a weak
reflection of the trough axis south across western Minnesota. There
is enhanced area of southwest winds at mid to upper levels with
speeds around 50 knots at 500mb and and a 70 to 80 knot jet around
300/200mb over the Northland this evening. At low levels a weak
surface low is over central Manitoba with a broad warm frontal zone
extending south across western/central Minnesota. To the south, an
east-west oriented warm front marks the boundary between the already
humid air up north and the very rich gulf moisture enhanced airmass
across the Southern and Mid-Mississippi River Valley where
precipitable water values approach two inches.

Late this morning through the early after a line of showers and
storms associated with the north-south oriented warm front will
continue eastward into northeast Minnesota, with a general weakening
trend as the front rotates a bit to become more northwest-to-
southeast oriented and lifts towards northwest Ontario. It will
essentially be exiting the area of greatest instability, with
easterly flow present across northeast Minnesota and adjacent areas
of northwest Ontario aiding in stabilizing the low level air due to
influence from Lake Superior. This area of precipitation will also
lead to overcast skies for much of the Northland today, which will
cause highs not to be as warm as past days, only in the upper 70s in
northeast Minnesota to the low 80s in northwest Wisconsin.

Late this afternoon and into tonight there is a chance for scattered
to widespread storms across east-central Minnesota into northwest
Wisconsin, but confidence is low in whether or not storms end up
forming this far north or if convection across central/southern MN
ends up developing and limiting the instability for storms to
develop this far north. There are a few possible scenarios for how
storms might evolve today (including the possibility that there
could be few to no storms), but in general there should be enough
instability combined with surface heating behind this morning's
storm (based on clouds clearing out on visible satellite) to cause a
few diurnally driving storms to develop in west-central Minnesota
this afternoon and track east towards central Minnesota (Brainerd
Lakes region). There is also a possibility for storms to develop
further north and cause another round of storms to impact areas
north of the Iron Range into the Minnesota Arrowhead this
afternoon/early evening, but this possibility seems low given the
low level stability driven by the easterly lake-influenced winds
across the Arrowhead today. Still, a few elevated isolated storms
are at least possible. As any thunderstorms evolve into the evening
hours they will track east-southeast along the instability gradient.
With strong mid/upper level winds and at least 1500 to 2000 j/kg
MUCAPE will be more than sufficient for a few strong to near severe
thunderstorms developing, with the greatest threat for hail/damaging
winds occurring with storms in the late afternoon early evening.
Storm motions should be fairly progressive, but with along-frontal
motion and precipitable water values near two inches, very heavy
rainfall rates are likely which could lead lead to at least
localized flooding. The flood threat is certainly conditional on
storms actually developing, but there do seem to be strong signals
from even non-CAMs on the potential for very heavy rain rates, and
flash flooding will likely be the primary concern with these storms
for east-central MN into northwest Wisconsin.

Late tonight storms exit to the south and large-scale subsidence
leads to clearing skies. Some fog is possible overnight, with lows
in the 60s, except across the MN Arrowhead where lows will fall into
the mid 50s.

Without a strong cold front to clear out the low level moisture,
Thursday will another humid day with dew points in the 60s. South to
southwesterly flow develops at low levels bringing a return of well
above normal temperatures with highs in the mid to even upper 80s,
warmest across northwest Wisconsin. Skies should be mostly sunny,
with residual low/mid level moisture causing diurnally driven cu to
develop in some areas during the afternoon. There is a chance for
isolated showers and storms in the afternoon as well, and while
storms will be more of the isolated variety given the convective
inhibition (CIN) expected to be present, 1000 to 2000 j/kg SBCAPE
and 40 to 50 knots of deep layer shear (mainly in the form of
unidirectional speed shear) could lead to a strong to severe storm
or two, with a threat for large hail and damaging winds. Given the
conditional nature and likely isolated areal coverage of storms, the
severe weather risk is just marginal at this time but could
certainly be increased based on how storms evolve today/tonight.

.LONG TERM...(Thursday night through Wednesday)
Issued at 416 PM CDT Wed Jul 17 2019

Much the same story as the past several shifts. Very warm
conditions are expected for Friday with highs in the upper 70s
along the North Shore to the upper 80s and low 90s from Pine
County east into northwest Wisconsin. Heat indices will be in the
90 to 100 degree range in northwest Wisconsin. As mentioned
yesterday, there are some concerns regarding the ability to warm
the surface with a baroclinic zone south of the forecast area
Showers and storms may bubble and burble along the boundary.
Clouds and precipitation chances would work to keep the
temperatures and heat indices cooler. However, if storms are
inhibited or develop late afternoon, these very warm conditions
will likely be realized. A more zonal flow pattern develops for
Saturday and Sunday. A few scattered thunderstorms are possible
Saturday night and Sunday. Temperatures will generally trend
cooler with highs in the upper 70s to low 80s. A slight bit
cooler for Sunday due to cloud cover and showers with highs
middle to upper 80s.

Northwesterly flow pattern develops for early next week as a high
amplitude upper ridge builds over the Rockies. Storms chances
return to the picture for Tuesday and Tuesday night.

&&

.AVIATION...(For the 00Z TAFS through 00Z Thursday evening)
Issued at 653 PM CDT Wed Jul 17 2019

Storms have developed around KINL as of issuance time, and should
continue for another hour or two, and also spread to also affect
KHIB until 06z. Am most confident in these two sites, but KDLH and
KBRD may also experience storms an have included some -SHRA groups
and VCTS for both sites. There is a fair amount of uncertainty as
to timing and location of storms for the next 6 to 12 hours, but
should be followed by a period of MVFR ceilings/visibilities in
showers before moving out of the area. Sites that clear before 06z
may experience fog, and have included some MVFR visibilities in
the 09z-12z time range. After 12z all sites should return to VFR.

&&

.MARINE...
Issued at 416 PM CDT Wed Jul 17 2019

Northeast winds will continue into this evening and will be
strongest in the southwest arm of Lake Superior where sustained
winds of 15 to 20 knots are expected with gusts a few knots
higher yet again. Small Craft Advisory will remain in effect.
Thunderstorms are possible late this evening and overnight, which
may create wind gusts of 35 to 45 knots. Winds veer southwesterly
for Thursday with sustained winds of 5 to 15 knots.

&&

.PRELIMINARY POINT TEMPS/POPS...
DLH  62  84  65  85 /  80  10  10  30
INL  62  83  60  80 /  60  30  30  10
BRD  67  86  68  85 /  80  10  20  20
HYR  68  86  66  90 /  90  30  20  30
ASX  64  87  66  89 /  90  30  10  30

&&

.DLH WATCHES/WARNINGS/ADVISORIES...
WI...Beach Hazards Statement until 9 PM CDT this evening for WIZ001.

MN...Beach Hazards Statement until 9 PM CDT this evening for MNZ037.

LS...Small Craft Advisory until 10 PM CDT this evening for LSZ143>146.

&&

UPDATE...LE
SHORT TERM...JJM
LONG TERM...Huyck
AVIATION...LE
MARINE...JJM

Hazardous Weather Outlook
National Weather Service Duluth MN
418 PM CDT Wed Jul 17 2019

MNZ037-WIZ001-182130-
Carlton/South St. Louis-Douglas-
418 PM CDT Wed Jul 17 2019

This Hazardous Weather Outlook is for portions of northeast
Minnesota and northwest Wisconsin.

.DAY ONE...This afternoon and Tonight

Strong northeast winds will increase the threat of rip currents
today through this evening for areas near the Twin Ports,
including the beaches of Duluth and Superior. A Beach Hazards
Statement has been issued for these areas.

There is a chance for strong to severe thunderstorms across
northeast Minnesota and across northwest Wisconsin late this
afternoon into this evening. If storms develop, some will be
capable of producing large hail and damaging winds. A tornado
cannot be ruled out either, especially across north-central
Minnesota. Storms will also produce heavy rainfall rates,
especially as they move across east- central Minnesota into
northwest Wisconsin tonight, which may lead to flash flooding.

.DAYS TWO THROUGH SEVEN...Thursday through Tuesday

Several rounds of thunderstorms are possible Friday through
Monday. Warm and humid conditions will continue Friday with heat
indices in the 90 to 100 degree range. Thunderstorm chances, both
in the Northland and in areas to our southwest and south, may
limit the heating Friday.

.SPOTTER INFORMATION STATEMENT...

Skywarn spotters may be needed today and tonight.

MNZ010>012-018>021-025-026-033>036-038-WIZ002>004-006>009-182130-
Koochiching-North St. Louis-Northern Cook/Northern Lake-
North Itasca-Central St. Louis-Southern Lake/North Shore-
Southern Cook/North Shore-North Cass-South Itasca-South Cass-
Crow Wing-Northern Aitkin-South Aitkin-Pine-Bayfield-Ashland-Iron-
Burnett-Washburn-Sawyer-Price-
418 PM CDT Wed Jul 17 2019

This Hazardous Weather Outlook is for portions of northeast
Minnesota and northwest Wisconsin.

.DAY ONE...This afternoon and Tonight

There is a chance for strong to severe thunderstorms across
northeast Minnesota and across northwest Wisconsin late this
afternoon into this evening. If storms develop, some will be
capable of producing large hail and damaging winds. A tornado
cannot be ruled out either, especially across north-central
Minnesota. Storms will also produce heavy rainfall rates,
especially as they move across east-central Minnesota into
northwest Wisconsin tonight, which may lead to flash flooding.

.DAYS TWO THROUGH SEVEN...Thursday through Tuesday

Several rounds of thunderstorms are possible Friday through
Monday. Warm and humid conditions will continue Friday with heat
indices in the 90 to 100 degree range. Thunderstorm chances, both
in the Northland and in areas to our southwest and south, may
limit the heating Friday.

.SPOTTER INFORMATION STATEMENT...

Skywarn spotters may be needed today and tonight.

LSZ121-140>148-182130-
Bayfield to Oak Point WI-Grand Portage to Grand Marais MN-
Grand Marais to Taconite Harbor MN-
Taconite Harbor to Silver Bay Harbor MN-
Silver Bay Harbor to Two Harbors MN-Two Harbors to Duluth MN-
Duluth MN to Port Wing WI-Port Wing to Sand Island WI-
Sand Island to Bayfield WI-Oak Point to Saxon Harbor WI-
418 PM CDT Wed Jul 17 2019

This Hazardous Weather Outlook is for portions of the Nearshore
waters of western Lake Superior.

.DAY ONE...This afternoon and Tonight

Small Craft Advisory continues into this evening. Strong to
severe thunderstorms are possible late this evening and overnight.

.DAYS TWO THROUGH SEVEN...Thursday through Tuesday

Several additional rounds of thunderstorms are possible Friday
through Sunday evening.

JJM/Huyck

More information may be obtained at the following web address:
http://www.weather.gov/duluth (all lower case)

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE DULUTH MN
611 PM CDT WED JUL 17 2019

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0600 PM     TORNADO          3 N WIRT                47.77N 93.95W
07/17/2019                   ITASCA             MN   LAW ENFORCEMENT

            LAW ENFORCEMENT REPORTED A FUNNEL CLOUD THAT
            TOUCHED DOWN BRIEFLY ON COUNTY ROAD 14 NEAR
            COUNTY ROAD 31 HEADING EAST TOWARDS BIGFORK.
            LOCATION ESTIMATED BY RADAR.

&&

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE DULUTH MN
718 PM CDT WED JUL 17 2019

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0649 PM     TSTM WND DMG     LITTLEFORK              48.39N 93.56W
07/17/2019                   KOOCHICHING        MN   LAW ENFORCEMENT

            TREES DOWN ALONG HIGHWAY 65 NEAR LITTLEFORK
            AND TREES DOWN KNOCKING DOWN POWERLINES IN
            LITTLEFORK. TIME ESTIMATED BY RADAR.

&&

JS

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE DULUTH MN
759 PM CDT WED JUL 17 2019

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0649 PM     TSTM WND DMG     1 WNW LITTLEFORK        48.40N 93.57W
07/17/2019                   KOOCHICHING        MN   PUBLIC

            BLEACHERS DAMAGED AT FAIRGROUNDS IN
            LITTLEFORK. TREE DOWN ON A POWERLINE IN
            LITTLEFORK. TIME ESTIMATED BY RADAR.

&&

JS

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE DULUTH MN
803 PM CDT WED JUL 17 2019

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0745 PM     TSTM WND DMG     6 W GREANEY             47.96N 93.15W
07/17/2019                   KOOCHICHING        MN   TRAINED SPOTTER

            5 PINE AND POPPLE TREES THAT WERE ABOUT 2
            FEET IN DIAMETER KNOCKED DOWN DUE TO
            STRAIGHT LINE WINDS.

&&

JS

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