Special Weather Statement, NWS Twin Cities, MN

Area Forecast Discussion
National Weather Service Twin Cities/Chanhassen MN
311 PM CDT SUN MAY 29 2016

.SHORT TERM...(This evening through Monday)
Issued at 300 PM CDT Sun May 29 2016

Latest visible satellite and radar imagery show some widely
scattered showers and thunderstorms have managed to develop across
the area. Decent lapse rates remain in place, with MLCAPE values
from 250-1250 J/kg across the area, with the highest values over the
west and south where there was a bit more sunshine. Effective shear
is below 30 kt, and doesn't look to increase much if at all, so
storms should remain multi-cellular and at best cause small hail and
wind gusts to 30 or 40 mph. The CAMs all did a decent job with the
timing and location of this activity, and all of them suggest a
waning of things between 23Z and 02Z as we start to lose heating and
surface ridging works in from the west. So, kept some chance PoPs
going into the evening, before removing all of them by 9 PM. The
remainder of the short term period looks to be fairly quiet as the
weak surface ridge slides across the area. Re-introduced some chance
PoPs into the west/southwest Monday afternoon as a surface trough
works into the Plains and we begin to see warm advection and the
approach of a nice 850 mb theta-e ridge.

.LONG TERM...(Monday night through Sunday)
Issued at 300 PM CDT Sun May 29 2016

The main forecast concerns deal with the onset of precipitation
Monday night, and how long it will last on Tuesday. Other concerns
deal with temperatures and the changing pattern.

A strong storm system moving onshore across the Pacific Northwest
will intensify as it moves across the Rockies and into the Plains,
Upper Midwest by midweek. Models have been fairly consistent with
timing of the main short wave and strong theta-e advection moving
across Minnesota late Monday night. There should be a large area
of showers and thunderstorms spreading northward which leads to
widespread qpf amounts of 0.50" to 1.00" by Tuesday morning. There
should be a sharp cutoff of the precipitation field Tuesday
morning from southwest to northeast across MPX forecast area due
to the strength of the subsidence on the back side of the short
wave. Although the front will slowly moving eastward across
Minnesota Tuesday, the bulk of the precipitation should occur in
western Wisconsin Tuesday afternoon, and evening. Elsewhere,
lingering spotty showers will be possible in the afternoon in
Minnesota due to increasing lapse rates associated with the cold
pool of the Upper Low.

As the Upper Low slowly fills and moves eastward across the Upper
Midwest and Great Lakes region Wednesday and Wednesday night,
instability showers or storms are possible, especially in central
Mn where the depth of the moisture is greatest. It will be much
cooler on Wednesday as strong cold air advection leads to highs in
the 60s. Lows Thursday morning could drop into the low to middle
40s in central Mn if skies clear.

After this system departs the area, temperatures will begin to
moderate with another front moving across the area Friday night
and Saturday. Temperatures should begin to rebound into the 70s
and possibly lower 80s by next weekend.

&&

.AVIATION...(For the 18Z TAFS through 18Z Monday afternoon)
Issued at 1215 PM CDT Sun May 29 2016

We'll continue to see ceilings at most locations through the
afternoon with a fairly extensive cu field across the region in
the lingering cyclonic flow and decent lapse rates. A few SHRA will
likely develop, but tough to say where/when, so kept things VCSH
for now, and can amend if/when things develop and look likely to
impact a location. Thunder isn't out of the question given the
lapse rates and MLCAPE values above 1000 J/kg over a portion of
the area, although the better forcing is generally north/east of
the better instability. Otherwise, we should see things clear out
tonight, and things will then be quiet through the remainder of
the period.

KMSP...TAF reflects expected conditions with fairly good
confidence overall. Main uncertainty is with any precipitation
that may occur this afternoon, and at this point VCSH seems to be
the best way to handle things, with amendments possible if/when
things materialize.

/OUTLOOK FOR KMSP/
Monday night...MVFR ceilings and visibilities possible with a
chance of showers and thunderstorms. Southeast wind 5 to 15 knots.
Tuesday...MVFR ceilings and visibilities possible with a
chance of showers and thunderstorms. Southwest wind 5 to 15
knots.
Tuesday night...VFR. West wind 5 to 10 knots.
Wednesday and Wednesday night...MVFR ceilings and visibilities
possible with a chance of showers and thunderstorms. West wind 10
to 20 knots.
Thursday...VFR. Northwest wind 10 to 20 knots.

&&

.MPX Watches/Warnings/Advisories...
WI...None.
MN...None.
&&

SHORT TERM...
LONG TERM...JLT
AVIATION...

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
1155 AM CDT SUN MAY 29 2016

MNZ041>045-047>070-073>078-082>085-091>093-WIZ014>016-023>028-
301700-
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-
1155 AM CDT SUN MAY 29 2016

THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF CENTRAL
MINNESOTA...EAST CENTRAL MINNESOTA...SOUTH CENTRAL MINNESOTA...
SOUTHEAST MINNESOTA...SOUTHWEST MINNESOTA...WEST CENTRAL
MINNESOTA...NORTHWEST WISCONSIN AND WEST CENTRAL WISCONSIN.

.DAY ONE...THIS AFTERNOON AND TONIGHT

ISOLATED NON-SEVERE THUNDERSTORMS ARE POSSIBLE THIS AFTERNOON INTO
EARLY EVENING.

.DAYS TWO THROUGH SEVEN...MONDAY THROUGH SATURDAY

AN ACTIVE WEATHER PATTERN WILL REDEVELOP AND CONTINUE THROUGH THE
MIDDLE OF THE WEEK. THE BEST CHANCE FOR THUNDERSTORMS WILL BE
MONDAY NIGHT THROUGH TUESDAY NIGHT. THERE IS A THREAT FOR LOCALLY
HEAVY RAINFALL AND A FEW SEVERE STORMS DURING THIS PERIOD.

.SPOTTER INFORMATION STATEMENT...

SKYWARN SPOTTER ACTIVATION WILL NOT BE NEEDED.

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
520 PM CDT SUN MAY 29 2016

MNZ066>068-292245-
CARVER-SIBLEY-MCLEOD-
520 PM CDT SUN MAY 29 2016

...A STRONG THUNDERSTORM WILL AFFECT EAST CENTRAL MCLEOD...
SOUTHWESTERN CARVER AND NORTHEASTERN SIBLEY COUNTIES...

AT 520 PM CDT...A STRONG THUNDERSTORM WAS LOCATED NEAR GLENCOE...OR
13 MILES SOUTHEAST OF HUTCHINSON...MOVING EAST AT 35 MPH.

LOCATIONS IMPACTED INCLUDE...
GLENCOE...NORWOOD YOUNG AMERICA...GREEN ISLE...HAMBURG...PLATO AND
GLENCOE AIRPORT.

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.

LAT...LON 4470 9425 4488 9423 4487 9384 4461 9386
TIME...MOT...LOC 2220Z 273DEG 30KT 4479 9413

ADL