Special Weather Statement, NWS Twin Cities, MN

Area Forecast Discussion...UPDATED
National Weather Service Twin Cities/Chanhassen MN
1245 PM CDT Fri Jun 15 2018

.UPDATE...
Issued at 1132 AM CDT Fri Jun 15 2018

Upgraded the Heat Advisory to an Excessive Heat Warning for the
metro counties and expanded the Heat Advisory to include south
central Minnesota and St. Croix and Pierce counties in Wisconsin.

Temperatures and dew points late this morning have risen into the
upper 80s and lower 70s, respectively, late this morning. 925 mb
temperatures are expected to increase into the +27 to +30C this
afternoon with nearly full sun expected across south central/
east central Minnesota and far western WI. With decent mixing also
expected, we should rise into at least the mid 90s, and possibly
upper 90s in some areas. This will yield heat indices in the low
100s.

Scattered clouds and isolated showers and thunderstorms have
recently developed northwest of St. Cloud, extending southwestward
across west central MN. It is unclear how these will play out
today, but with rising heights we aren't expecting widespread
activity despite a fairly unstable airmass. The clouds may keep
temperatures a little cooler in that region, which is why we
haven't expanded the heat headlines in that direction.

Southeasterly flow behind convection over Wisconsin, along with
cirrus may also keep most of the Wisconsin counties a bit cooler.
If the flow can turn more southerly this afternoon, we should be
able to reach the predicted highs. Still, heat indices appear
borderline so held off on headlines there as well.

&&

.SHORT TERM...(Today and tonight)
Issued at 435 AM CDT Fri Jun 15 2018

Surface analysis early this morning shows a pair of low pressure
centers, one in southwestern Manitoba province and the other over
central South Dakota. A warm front extends south southeast from
the northernmost low, across southwestern Minnesota and continuing
into Missouri. A cold front then extends south from the Canadian
low into South Dakota then west towards the central Rockies.
Aloft, a ridge axis emanating from the deep South has shifted to
near Lake Michigan, allowing a pronounced southwest flow to
develop across the area. In addition, a potent southwesterly low
level jet has nudged its way into the area, which had aided
convective development in northern Minnesota into western
Wisconsin. A couple strong storms are possible this morning in
interior western Wisconsin but otherwise the convection will
remain outside the WFO MPX coverage area. As the warm front
slides east, strong warm air advection will take place along with
strong moisture advection. While the warm front will continue to
slide east and across the area today, the cold front will remain
to the west, allowing the hot and humid conditions to take over
the coverage area. Highs will climb to the upper 80s to lower 90s
while dewpoints surge to around 70 degrees. This combination will
not only create heightened instability but also high heat index
levels. For much of the area, heat indices will climb to between
95-100 degrees. These levels will create exacerbated heat illness
concerns for the Twin Cities metro area so have issued a Heat
Advisory for the 7-county metro for this afternoon. Conditions
will be closely monitored if heat indices climb above 100, which
would necessitate a Heat Advisory for counties outside the metro.
Regardless, remedies should be taken to avoid heat illnesses with
heat and humidity levels so high. With regard to the convection,
the deep warm layer would normally inhibit convection. However,
with the warm front acting as a low level convergence feature, the
deep moisture and a kicker upper level shortwave, convection is
expected to re-develop this afternoon into this evening for much
of the area, potentially as clustered thunderstorms in central-
eastern MN which could then organize into an MCS in western WI.
Still much uncertainty with respect to the details and exact
placement in the CAMs although there is general agreement among
the models that convection will re-fire this afternoon. As such,
thunderstorm mention is capped in the "chance" range even with
PoPs into the "likely" range. Steep mid-level lapse rates with
weakening shear as the low level jet moves away will hint at
elevated convection which could produce large hail. (This
environment is much less conducive to the formation of tornadoes
or storms producing damaging winds.) However, an additional
concern is heavy rain, especially over far eastern MN through
western WI, again due to moisture convergence with the front.
Should any training of storms occur, flooding may be a problem.
There is still some uncertainty in the details of where storms
will occur but enough confidence is there to not only advertise
the Slight Risk in the SPC SWODY1 product but also for WPC to
advertise a Slight Risk for excessive rainfall for much of the
coverage area.

.LONG TERM...(Saturday through Thursday)
Issued at 435 AM CDT Fri Jun 15 2018

We will likely see some convection continuing into at least
Saturday morning from previous nights activity. The NSSL-WRF and
GFS we similar in handling overall coverage of complex into Sunday
morning. After that, difficult to ascertain location of
redevelopment during the day. Will likely see quite a bit of cloud
cover lingering in the morning with outflow boundary and frontal
position in question. Does look like heat will build south of any
of this remnant complex, mainly over far southern MN for Saturday
afternoon. Will hold onto chance PoPs for redevelopment into the
afternoon. Higher PoPs held along the frontal boundary Saturday
night. Severe and heavy rain threat a possibility with slight
risks associated with those hazards at this time. PW's still
increase to around 1.75 inches which remains 2 to 3 standard
deviations above normal. So heavy rainfall possible. We have a 3
day total(Today through Monday) around 3 inches over the northern
third of the cwa at this time.

Cloud cover and frontal position will also affect overall heat
concerns. Wont be adding any headline at this time as it will most
likely be a day to day decision because of those uncertainties.
Still very humid with dewpoints into the lower 70s south of the
boundary.

Following the front Monday, cooler and drier air works over the
region through most of the work week. Models suggest an increasing
threat of moisture/instability moving into at least the southern
portion of the area late in the week as the next western trough
approaches the area.

&&

.AVIATION...(For the 18Z TAFS through 18Z Saturday afternoon)
Issued at 1245 PM CDT Fri Jun 15 2018

Showers and thunderstorms have decreased in intensity across
western Minnesota in the last hour or two in response to the mid
level ridge building in. There will likely continue to be
isolated-scattered showers and thunderstorms through the day, but
are not expected to be organized. A better threat will develop
overnight, possibly in the form of an organized complex of storms,
so included a PROB30 for all the TAF sites.

KMSP...Confidence in showers and storms impacting the terminal are
very low. The storms to the west are losing intensity and coverage
as they head east. Preferred to err on the side of a dry forecast
until it becomes more clear storms may impact the terminal,
otherwise there would have to be several hours of TS. An
amendment will be issued when trends become clearer.

/OUTLOOK FOR KMSP/
Sun...Mainly VFR. Chc MVFR/TSRA. Wind SSW 5-10 kts.
Mon...Mainly VFR. Chc MVFR/TSRA. Wind NE 5-10 kts.
Tue...VFR. Wind NE 5-10 kts.

&&

.MPX WATCHES/WARNINGS/ADVISORIES...
WI...Heat Advisory until 7 PM CDT this evening for WIZ023-024.

MN...Excessive Heat Warning until 7 PM CDT this evening for
     MNZ060>063-068>070.

     Heat Advisory until 7 PM CDT this evening for MNZ051-059-066-067-
     074>078-082>085-091>093.

&&

UPDATE...BORGHOFF
SHORT TERM...JPC
LONG TERM...DWE
AVIATION...BORGHOFF

Hazardous Weather Outlook...UPDATED
National Weather Service Twin Cities/Chanhassen MN
1238 PM CDT Fri Jun 15 2018

MNZ041>045-047>050-052>058-064-065-073-WIZ014>016-025>028-161745-
Douglas-Todd-Morrison-Mille Lacs-Kanabec-Stevens-Pope-Stearns-
Benton-Isanti-Chisago-Lac Qui Parle-Swift-Chippewa-Kandiyohi-
Meeker-Yellow Medicine-Renville-Redwood-Polk-Barron-Rusk-Dunn-
Pepin-Eau Claire-
1238 PM CDT Fri Jun 15 2018

This Hazardous Weather Outlook is for portions of central
Minnesota...east central Minnesota...southwest Minnesota...west
central Minnesota...northwest Wisconsin and west central
Wisconsin.

.DAY ONE...This Afternoon and Tonight

There is a chance of thunderstorms and a few may be severe. Large
hail, damaging winds, and heavy rainfall are possible.

Heat indices may rise to the mid 90s this afternoon.

.DAYS TWO THROUGH SEVEN...Saturday through Thursday

Periods of thunderstorms are possible Saturday through Monday
night. Some storms may be severe Saturday through Sunday. The
main risks are large hail and damaging winds. There is also a
flooding concern with several inches of rain possible.

In addition, excessive heat and humidity will impact much of the
area through Sunday. Heat indices for areas south of Interstate
94 will likely range from 95 to 100 Saturday and Sunday.

.SPOTTER INFORMATION STATEMENT...

SKYWARN spotter activation may be needed.

MNZ060>063-068>070-161745-
Hennepin-Anoka-Ramsey-Washington-Carver-Scott-Dakota-
1238 PM CDT Fri Jun 15 2018

This Hazardous Weather Outlook is for portions of east central
Minnesota.

.DAY ONE...This Afternoon and Tonight

An Excessive Heat Warning is in effect for this afternoon. Heat
indices of 98 to 103 are expected.

There is a chance of thunderstorms and a few may be severe. Large
hail, damaging winds, and heavy rainfall are possible.

.DAYS TWO THROUGH SEVEN...Saturday through Thursday

Excessive heat and humidity will continue through Sunday. Heat
indices will likely range from 95 to 103.

Periods of thunderstorms are possible Saturday through Monday
night. Some storms may be severe Saturday through Sunday. The
main risks are large hail and damaging winds. There is also a
flooding concern with several inches of rain possible.

.SPOTTER INFORMATION STATEMENT...

SKYWARN spotter activation may be needed.

MNZ051-059-066-067-074>078-082>085-091>093-WIZ023-024-161745-
Sherburne-Wright-McLeod-Sibley-Brown-Nicollet-Le Sueur-Rice-
Goodhue-Watonwan-Blue Earth-Waseca-Steele-Martin-Faribault-
Freeborn-St. Croix-Pierce-
1238 PM CDT Fri Jun 15 2018

This Hazardous Weather Outlook is for portions of central
Minnesota...south central Minnesota...southeast Minnesota and
west central Wisconsin.

.DAY ONE...This Afternoon and Tonight

A Heat Advisory is in effect for this afternoon. Heat indices of
98 to 103 are expected.

There is a chance of thunderstorms and a few may be severe. Large
hail, damaging winds, and heavy rainfall are possible.

.DAYS TWO THROUGH SEVEN...Saturday through Thursday

Periods of thunderstorms are possible Saturday through Monday
night. Some storms Saturday through Sunday may be severe. The
main risks are large hail and damaging winds. There is also a
flooding concern with several inches of rain possible.

In addition, excessive heat and humidity will impact much of the
area through Sunday. Heat indices will likely range from 95 to
103.

.SPOTTER INFORMATION STATEMENT...

SKYWARN spotter activation may be needed.

Borghoff

Special Weather Statement
National Weather Service Twin Cities/Chanhassen MN
326 PM CDT FRI JUN 15 2018

MNZ078-152100-
Goodhue-
326 PM CDT FRI JUN 15 2018

...A STRONG THUNDERSTORM WILL AFFECT EAST CENTRAL GOODHUE COUNTY...

At 325 PM CDT, a strong thunderstorm was located near Goodhue, or 7
miles south of Red Wing, moving east at 30 mph.

Winds in excess of 30 mph and nickel size hail are possible with this
storm.

Locations impacted include...
Goodhue, Frontenac, Frontenac State Park and Central Point.

This includes U.S. Highway 61 between mile markers 82 and 84.

Frequent cloud to ground lightning is occurring with this storm.
Lightning can strike 10 miles away from a thunderstorm. Seek a safe
shelter inside a building or vehicle.

To report severe weather, contact your nearest law enforcement
agency. They can relay your report to the National Weather Service
office in The Twin Cities.

LAT...LON 4440 9263 4450 9263 4455 9232 4452 9230
      4450 9230 4446 9224 4445 9243 4437 9244
TIME...MOT...LOC 2025Z 267DEG 26KT 4444 9257

JLT