Damaging Wind in Minnesota, July 1, 2020

Area Forecast Discussion...UPDATED
National Weather Service Twin Cities/Chanhassen MN
1051 PM CDT Tue Jun 30 2020

.SHORT TERM...(This evening through Wednesday night)
Issued at 315 PM CDT Tue Jun 30 2020

A blocking pattern still dominates North America, with a through
over the northern Rockies and broad ridging east of the Rockies.
That western through has taken on a negative tilt and will track
across the Dakotas through tonight. At the surface, we have a
stationary front draped across southern MN and that combined with
recent heavy rainfall has allowed dewpoints to pool well into the
uncomfortable category up in the mid 70s. We have heat indices
pushing up into the mid 90s, with wet bulb globe temperatures around
82/83 degrees, both getting into the lower end of our head advisory
criteria (for the Twin Cities metro), but with the breeze and cloud
cover taking a little bite out of the heat, have decided to go with
no heat headlines. Although this setup has resulted in a rather
unstable environment, 12z KMPX sounding showed rather stout capping
around h8 and this capping looks like it will hold for today, with
no rain expected in the area until a complex approaches us tonight
from the Dakotas.

For tonight, CAMs are in good agreement of a line of thunderstorms
developing ahead of the trough in the central Dakotas. That line
will be poised to cross into western MN around 6z, but as they move
into MN they will be on a rather serious downward trend. The problem
is the parent wave forcing it remains well to our west. Also, the
LLJ all but disappears as well, as the nocturnal strengthening
shifts across eastern MN. The net result is these storms rapidly
weaken as they lose their forcing and look unlikely to make it as
far east as the I-35 corridor. There is some severe threat out along
the Dakotas border, but with the weakening trend expected to be well
under way by the time storms reach western MN, the severe threat
looks rather low and confined to strong wind gusts.

For Wednesday, this boundary becomes almost washed out from N-S
across the middle of MN. In addition, we'll see building mid level
heights Wednesday, which will result in warmer mid level temps and
weaker lapse rates, which means no more 5000+ j/kg of MUCAPE. With
the weak forcing, we're only looking for widely scattered diurnally
driven thunderstorms to develop across the eastern half of MN into
western WI, with the severe threat very low thanks to little shear
and lower instability. With the increased cloud cover expected, it
will be a couple of degrees cooler tomorrow, so we are not
anticipating needing any heat headlines.

.LONG TERM...(Thursday through Tuesday)
Issued at 315 PM CDT Tue Jun 30 2020

For the long term, Thursday through the weekend will be dominated by
upper ridging, with the northern stream getting pushed well north
into Canada. Next week, the ridge looks to flatten and northern
stream move back south, closer to the northern tier of CONUS states.
The net result will be hot, humid, and mainly dry conditions
Thursday through Sunday. Next week looks a little cooler and
potential more active as the northern stream moves closer and
potential for thunderstorms increases.

Thursday, what's left of the weak boundary over MN on Wednesday will
shift to the MN/WI border on Thursday. It looks to be dry given the
high heights overhead, but there's enough instability left over in
western WI to where a few models show storms developing there, but
it looks like a bit of a stretch. Otherwise, the next chance for
precip looks to come Saturday night as deterministic models continue
to show potential for a complex to make a run for central MN after
initiating near the international border in response to a weak
shortwave overtopping the ridge. For Thursday through Sunday, we'll
see afternoon highs around 90, with dewpoints near 70. So pretty
much every day will have potential for heat headlines, but right now
it looks like we would need nothing more than advisories.

Next week, as the ridge flattens, we get into more of a "ring of
fire" looking pattern. The result from the NBM were PoPs that are
essentially climatology. Though Monday night looks to have the
greatest potential for storms right now, with the ECMWF/GEM/GFS all
show a weak boundary making a run into the upper MS Valley.

&&

.AVIATION...(For the 06Z TAFS through 06Z Wednesday night)
Issued at 1051 PM CDT Tue Jun 30 2020

Scattered VFR CU will prevail through the period. Scattered
thunderstorms are developing across eastern South Dakota which
will advance into far western MN and dissipate overnight as they
head toward the TAF sites.

KMSP...No concerns tonight.

/OUTLOOK FOR KMSP/
Thu...VFR. Wind calm.
Fri...VFR. Wind ESE 5 kts.
Sat...VFR. Wind S 5 kts.

&&

.MPX WATCHES/WARNINGS/ADVISORIES...
WI...None.
MN...None.
&&

SHORT TERM...MPG
LONG TERM...MPG
AVIATION...Borghoff

Hazardous Weather Outlook...UPDATED
National Weather Service Twin Cities/Chanhassen MN
943 PM CDT Tue Jun 30 2020

MNZ041-042-047>049-054>058-064-065-073-074-082-091-020245-
Douglas-Todd-Stevens-Pope-Stearns-Lac Qui Parle-Swift-Chippewa-
Kandiyohi-Meeker-Yellow Medicine-Renville-Redwood-Brown-Watonwan-
Martin-
943 PM CDT Tue Jun 30 2020

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

.DAY ONE...Tonight.

There is a chance of thunderstorms late tonight. The probability
for severe weather is low.

.DAYS TWO THROUGH SEVEN...Wednesday through Monday.

There are small chances for thunderstorms Saturday night through
Monday. The threat for severe weather is low.

Hot and humid conditions are expected through the weekend.
Heat indices in the low to mid 90s are possible during the
afternoons.

.SPOTTER INFORMATION STATEMENT...

SKYWARN spotter activation will not be needed.

MNZ043>045-050>053-059>063-066>070-075>078-083>085-092-093-
WIZ014>016-023>028-020245-
Morrison-Mille Lacs-Kanabec-Benton-Sherburne-Isanti-Chisago-
Wright-Hennepin-Anoka-Ramsey-Washington-McLeod-Sibley-Carver-
Scott-Dakota-Nicollet-Le Sueur-Rice-Goodhue-Blue Earth-Waseca-
Steele-Faribault-Freeborn-Polk-Barron-Rusk-St. Croix-Pierce-Dunn-
Pepin-Chippewa-Eau Claire-
943 PM CDT Tue Jun 30 2020

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

.DAY ONE...Tonight.

No hazardous weather is expected at this time.

.DAYS TWO THROUGH SEVEN...Wednesday through Monday.

There are small chances for thunderstorms Saturday night through
Monday. The threat for severe weather is low.

Hot and humid conditions are expected through the weekend.
Heat indices in the low to mid 90s are possible during the
afternoons.

.SPOTTER INFORMATION STATEMENT...

SKYWARN spotter activation will not be needed.

Borghoff