Special Weather Statement, NWS Twin Cities, MN

Area Forecast Discussion
National Weather Service Twin Cities/Chanhassen MN
729 AM CDT Sun Jun 30 2019

.UPDATE...
Issued at 643 AM CDT Sun Jun 30 2019

Updated to include 12z aviation discussion below.

&&

.SHORT TERM...(Today through Monday)
Issued at 425 AM CDT Sun Jun 30 2019

Surface analysis early this morning shows a low pressure center
near the ND/SD/MN border triple point with a warm front snaking
SE into central IA and a trailing cold front extending SW into the
central Plains. This cold front aligns with a nearly N-S cold
frontal boundary extending south from central Manitoba province.
Aloft, the center of the dome of high pressure remains over the
central Plains to southwestern CONUS with the northern periphery
having flattened out. A fairly well defined shortwave trough axis
is analyzed from northern Saskatchewan province and extends
southwest into the northern Rockies.

This morning, a fairly well organized MCS progressed eastward over
northern MN from the Dakotas but is starting to run into the
remnants of the persistent ridge and is losing its punch. Still a
decent chance this complex may shift across northeastern portions
of the WFO MPX coverage area (east-central MN into northwestern
WI) before weakening. However, attention then returns to central
MN where multiple runs of the HRRR try to develop additional
rounds of convection later this afternoon into this evening,
potentially as another MCS over central MN which may drive SE into
western WI. Difficult to pin down exactly where this may occur
since this will be outflow-driven in conjunction with the
progressing cold front and shortwave trough aloft. Lapse rates
will still be stout within a highly unstable atmosphere (dewpoints
into the lower 70s contributing to MUCAPE of at least 4000 J/kg).
Have capped PoPs in the chance category this afternoon due to the
uncertainty of storm location although confidence is fairly high
that an additional MCS will actually occur.

The cold front will push east through the day today and stall out
over southern MN tonight through Monday. In addition, the upper
ridge will continue to be suppressed to the south, aligning upper
level flow with the E-W oriented stalled cold front. This will
allow multiple disturbances to ride within the now zonal flow atop
the cold front within the highly moisture environment (PWATs 1.4"
to 1.7"). As such, chances for showers/thunderstorms increase
into the likely category for much of the area tonight through
tomorrow with periods of showers/thunderstorms likely to push
through the area. The unstable atmosphere will persist while
unidirectional bulk shear increases to 35-40kt so there is some
potential for additional severe weather on Monday. As such, a
small Slight Risk area in SW MN with a Marginal Risk up to the
I-94 corridor is certainly warranted.

The other concern is obviously the heat/humidity in place for
today. With the area being warm-sectored, highs will range from
the upper 80s to lower 90s today. Dewpoints will solidly hit the
lower 70s and potentially the middle 70s. This will easily put
heat index values around 100 degrees for much of southern and
east-central MN. Thus, have maintained the Excessive Heat Warning
for the 7-county Twin Cities metro with a Heat Advisory
surrounding the warning in Minnesota and expanding across much of
southern MN. With the passage of the cold front later today and
modest cold air advection setting in, highs on Monday will range
from the upper 70s to the mid 80s.

.LONG TERM...(Monday night through Saturday)
Issued at 425 AM CDT Sun Jun 30 2019

The main issue in the long term period will be the stalled out
frontal boundary across southern MN initially and the potential
for heavy rainfall and strong thunderstorms Monday night. The
front will sag south mid week, before lifting back north for the
latter half of the week. Hence, an active period ahead with
chances for thunderstorms throughout the week. Strong high
pressure from our north still looks to drive south across the
upper midwest by next weekend.

By Monday night, the stationary front will be oriented west to
east along the MN-IA border. Mid level shortwave energy will
translate through the area as well, providing support to nocturnal
thunderstorms as the low level jet develops and provides strong
moisture transport in from the southwest given 30+ knot 850mb
wind. Precipitable water values around 2" will be available across
southern MN along with a weakly sheared, but unstable
environment. Hence, the slight risk of excessive rainfall from the
WPC makes sense for this time period. Thunderstorms Monday night
will be efficient heavy rain producers, and would expect isolated
locations to receive a couple inches of rain.

A cool front will drop in from the north on Tuesday, and push the
stationary front south into Iowa. The latter half of Tuesday
through Wednesday look dry locally, but a subtle upper level
shortwave will move east across the area during this time, and the
upper level height falls could lead to isolated shower and
thunderstorm development during this window, hence the slight
chance pops in the forecast.

A couple more pronounced waves will move through the area
Thursday through Friday, but uncertainty is high in placement and
timing of these features. They would present more opportunity for
periodic thunderstorms. Guidance still in decent agreement on
bringing a large area of high pressure into the region from the
north next weekend.

&&

.AVIATION...(For the 12Z TAFS through 12Z Monday morning)
Issued at 643 AM CDT Sun Jun 30 2019

Tricky forecast with respect to convection as what is happening
now will determine what happens later due mainly to residual
outflow boundaries within the highly unstable atmosphere.
Convection is still possible this morning, especially at the WI
TAF sites. Even without the morning convection, the southward-
moving outflow will cause a quick wind shift to NE with winds
around 20G40kt for a few hours before the atmosphere recovers to
have SE to S winds later. Additional storms will likely develop by
late evening with a mixture of -RA and TSRA which could
potentially produce MVFR-IFR conditions. Will take a conservative
approach at this point and see how convective models evolve the
situation for later on.

KMSP...Strong outflow boundary this morning will cause a
quick/strong wind shift to NE which may persist for a couple-few
hours before resuming out of the prevailing southerly direction.
Chances for convection this morning are low but still possible by
late morning. Convection chances increase this evening but will
need to see how the situation evolves before going anything more
than VCTS.

/OUTLOOK FOR KMSP/
Mon-Wed...VFR. Chc MVFR/TSRA. Winds LGT and VRB.

&&

.MPX WATCHES/WARNINGS/ADVISORIES...
WI...None.
MN...Excessive Heat Warning until 9 PM CDT this evening for
     MNZ060>063-068>070.

     Heat Advisory until 9 PM CDT this evening for MNZ051>053-059-066-
     067-073>078-082>085-091>093.

&&

UPDATE...JPC
SHORT TERM...JPC
LONG TERM...SPD
AVIATION...JPC

Hazardous Weather Outlook
National Weather Service Twin Cities/Chanhassen MN
338 AM CDT Sun Jun 30 2019

MNZ041>045-047>070-073>078-082>085-091>093-WIZ014>016-023>028-
010900-
Douglas-Todd-Morrison-Mille Lacs-Kanabec-Stevens-Pope-Stearns-
Benton-Sherburne-Isanti-Chisago-Lac Qui Parle-Swift-Chippewa-
Kandiyohi-Meeker-Wright-Hennepin-Anoka-Ramsey-Washington-
Yellow Medicine-Renville-McLeod-Sibley-Carver-Scott-Dakota-
Redwood-Brown-Nicollet-Le Sueur-Rice-Goodhue-Watonwan-Blue Earth-
Waseca-Steele-Martin-Faribault-Freeborn-Polk-Barron-Rusk-
St. Croix-Pierce-Dunn-Pepin-Eau Claire-
338 AM CDT Sun Jun 30 2019

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

.DAY ONE...Today and Tonight

Excessive heat will continue today. Heat indices will likely
exceed 100 again for much of southern Minnesota, including the
Twin Cities metro. An Excessive Heat Warning remains in place for
the Twin Cities metro with a Heat Advisory surrounding the warning
in Minnesota and encompassing much of southern Minnesota.

There is a Slight Risk for severe thunderstorms for much of
central and southern Minnesota with a Marginal Risk of severe
thunderstorms for portions of west central Minnesota. Damaging
winds will be the main hazard. In addition, some thunderstorms may
produce heavy rain which could produce isolated flooding.

.DAYS TWO THROUGH SEVEN...Monday through Saturday

Periods of thunderstorms are expected for much of next week with
some severe weather possible.

.SPOTTER INFORMATION STATEMENT...

SKYWARN spotter activation may be needed this afternoon in Monday.

Special Weather Statement
National Weather Service Twin Cities/Chanhassen MN
544 AM CDT Sun Jun 30 2019

MNZ045-052-053-WIZ014-301115-
Isanti-Kanabec-Chisago-Polk-
544 AM CDT Sun Jun 30 2019

...A LINE OF STORMS WILL AFFECT SOUTHERN KANABEC...CHISAGO...ISANTI
AND NORTHERN POLK COUNTIES...

At 543 AM CDT, radar indicated strong thunderstorms were located
along a line extending from near Webster to 6 miles southeast of Rush
City to near Princeton. Movement was south at 35 mph.

Winds in excess of 40 mph are possible with these storms.

These storms will be near...
  North Branch around 550 AM CDT.
  St. Francis around 605 AM CDT.
  Chisago City around 610 AM CDT.
  Lindstrom, Taylors Falls and Center City around 615 AM CDT.

Other locations impacted by these storms include Mora Airport,
Spencer Brook, Wild River State Park, Harris, Athens, Stanchfield,
Cambridge Airport, Lewis Lake, Grandy and Spring Lake.

This includes Interstate 35 between mile markers 141 and 163.

LAT...LON 4588 9314 4574 9314 4573 9285 4564 9288
      4565 9253 4573 9252 4572 9216 4560 9216
      4539 9279 4540 9302 4541 9302 4541 9348
      4594 9352
TIME...MOT...LOC 1043Z 341DEG 29KT 4583 9228 4562 9289 4560 9350

SPD

Special Weather Statement
National Weather Service Twin Cities/Chanhassen MN
606 AM CDT Sun Jun 30 2019

MNZ053-WIZ014>016-023-025-301200-
Chisago-Polk-Barron-St. Croix-Dunn-Rusk-
606 AM CDT Sun Jun 30 2019

...A LINE OF STORMS WILL AFFECT EAST CENTRAL CHISAGO...NORTHWESTERN
RUSK...NORTHWESTERN DUNN...NORTHEASTERN ST. CROIX...BARRON AND
SOUTHEASTERN POLK COUNTIES...

At 605 AM CDT, radar indicated strong thunderstorms were located
along a line extending from near Stone Lake to near Centuria.
Movement was southeast at 40 mph.

Winds in excess of 40 mph are possible with these storms.

These storms will be near...
  Amery around 630 AM CDT.
  Clear Lake around 640 AM CDT.
  Clayton around 645 AM CDT.
  Prairie Farm around 700 AM CDT.

Other locations impacted by these storms include Cumberland Airport,
Hillsdale, Range, Wanderoos, Brill, Shafer, Joel, Barronett, Mckinley
and Reeve.

This includes the following highways...
 U.S. Highway 53 between mile markers 127 and 152.
 U.S. Highway 8 in Minnesota between mile markers 17 and 22.
 U.S. Highway 61 near mile marker 165.

LAT...LON 4561 9082 4510 9214 4541 9280 4566 9216
      4564 9215 4564 9087
TIME...MOT...LOC 1105Z 308DEG 34KT 4586 9150 4548 9263

SPD

Special Weather Statement
National Weather Service Twin Cities/Chanhassen MN
643 AM CDT Sun Jun 30 2019

WIZ015-016-025-027-028-301245-
Chippewa-Barron-Dunn-Eau Claire-Rusk-
643 AM CDT Sun Jun 30 2019

...A LINE OF STORMS WILL AFFECT RUSK...DUNN...CHIPPEWA...NORTHWESTERN
EAU CLAIRE AND SOUTHEASTERN BARRON COUNTIES...

At 642 AM CDT, radar indicated strong thunderstorms were located
along a line extending from 6 miles east of Exeland to near
Weyerhaeuser to near Clear Lake. Movement was southeast at 45 mph.

Winds in excess of 40 mph are possible with these storms.

These storms will be near...
  Boyceville around 705 AM CDT.
  Wheeler around 710 AM CDT.
  Cornell around 715 AM CDT.
  Menomonie and Colfax around 720 AM CDT.
  Elk Mound and Boyd around 730 AM CDT.
  Stanley around 735 AM CDT.

Other locations impacted by these storms include Cedar Falls, Tony,
Island Lake, Holcombe, Tainter Lake, Tilden, Otter Lake, Jim Falls,
Conrath and Ingram.

This includes the following highways...
 Interstate 94 in Wisconsin between mile markers 41 and 62.
 U.S. Highway 53 between mile markers 90 and 128.

LAT...LON 4537 9092 4491 9093 4476 9183 4511 9214
      4512 9213 4513 9216 4516 9215 4539 9147
      4565 9086 4563 9067 4538 9068
TIME...MOT...LOC 1142Z 321DEG 38KT 4566 9111 4538 9145 4524 9219

SPD

<!doctype html>
<html lang="en">
<head>
  <meta charset="utf-8">
  <meta name="viewport" content="width=device-width, initial-scale=1">
  <title>Service Notice</title>
  <link rel="stylesheet" href="index.css">
</head>
<body>
  <main class="wrap">
    <section class="card" role="status" aria-live="polite">
      <div class="status" id="status">Temporary Notice</div>
      <h1 id="headline">This service is currently unavailable.</h1>
      <p id="message1">
        The site you requested is temporarily down for maintenance or an unexpected outage.
      </p>
      <p id="message2">
        Please try again in a few minutes.
      </p>
      <p class="small" id="detail">
        If you are an administrator, restore upstream service and remove the redirect/fallback rule when normal operations resume.
      </p>
    </section>
  </main>
  <script src="index.js"></script>
</body>
</html>

<!doctype html>
<html lang="en">
<head>
  <meta charset="utf-8">
  <meta name="viewport" content="width=device-width, initial-scale=1">
  <title>Service Notice</title>
  <link rel="stylesheet" href="index.css">
</head>
<body>
  <main class="wrap">
    <section class="card" role="status" aria-live="polite">
      <div class="status" id="status">Temporary Notice</div>
      <h1 id="headline">This service is currently unavailable.</h1>
      <p id="message1">
        The site you requested is temporarily down for maintenance or an unexpected outage.
      </p>
      <p id="message2">
        Please try again in a few minutes.
      </p>
      <p class="small" id="detail">
        If you are an administrator, restore upstream service and remove the redirect/fallback rule when normal operations resume.
      </p>
    </section>
  </main>
  <script src="index.js"></script>
</body>
</html>