Area Forecast Discussion
Issued by NWS Twin Cities, MN

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FXUS63 KMPX 290037

Area Forecast Discussion
National Weather Service Twin Cities/Chanhassen MN
737 PM CDT SAT MAY 28 2016

.SHORT TERM...(This evening through Sunday)
Issued at 345 PM CDT Sat May 28 2016

Concerns are thunderstorms late this afternoon and evening and
another threat tomorrow afternoon.

Upper low is on the move and is now into southeastern South Dakota.
Models open it up as a wave later tonight and the trough axis should
be out of western Wisconsin Sunday mid morning. Brief upper ridging
takes place, but with relatively zonal flow from the Pacific coast
to the Upper Midwest, it appears that a weak short wave will move
across the Dakotas Sunday afternoon.

Meanwhile a surface low was just north of Sioux City, with a front
extending northeast to the southeast Twin Cities metro and then
toward Rice Lake. Modest instability has been evident across
southern Minnesota into Wisconsin, and with a bit of clearing late
this morning, showers and a few storms quickly developed. With not
much shear, decent low level lapse rates and some instability, a
boundary in the area, and upper low just west of us, it is possible
there may be a funnel cloud or two and maybe even a landspout
tornado. This threat will taper off early this evening.

North of the boundary, an abundance of low clouds will keep
temperatures from dropping too much tonight. Lows should mainly be
55-60. There is enough low level moisture so that it will take quite
some time before clearing takes place, most likely Sunday

The clearing tomorrow morning will open the door for the potential
of more storms Sunday afternoon as the next short wave arrives. A
variety of models show more instability late tomorrow afternoon. In
fact, there looks to be more CAPE tomorrow than today. Moisture will
be sufficient, especially in eastern Minnesota and Wisconsin. Thus
there may be more storms Sunday afternoon.

.LONG TERM...(Sunday night through Saturday)
Issued at 345 PM CDT Sat May 28 2016

Main forecast concern is timing of Monday nights` precipitation

Dry conditions should prevail Sunday night through Monday
afternoon as a dry west-northwest flow continues, and moisture
remains limited. There is some uncertainty late Monday afternoon
in southwest/south central Minnesota as moisture begins to return
ahead of a storm system across the Rockies. Depending upon the
speed and moisture return, parts of southwest/south central
Minnesota could see a few thunderstorms by the late afternoon.
Otherwise, the bulk of the precipitation should hold off until
late Monday night, and Tuesday as strong moisture advection and a
negatively tilted trough moves across the Upper Midwest. I
wouldn`t be surprised to see severe thunderstorms Tuesday
afternoon in west central/southwest/south central Minnesota based
on shear and MLCAPE values. Behind this system, a cool/cold air
mass moves in, and last for a few days. This cool period has been
advertised by the models but the strength of the colder air
remains questionable. Models have lowered highs by
Thursday/Friday, but these numbers could be lower if more of the
air mass originates in north central Canada, vs, the Canadian
Rockies. Some of the GEFS plumes on temperatures by late in the
week have lows back in the 40s in the Twin Cities, with highs in
the 60s.


.AVIATION...(For the 00Z TAFS through 00Z Sunday evening)
Issued at 724 PM CDT Sat May 28 2016

Isolated to scattered showers will continue for the next several
hours, but outside of KEAU, there shouldn`t be thunderstorms near
the TAF sites. In addition to the rain, there is a mix of VFR/MVFR
ceilings. We think some of these low clouds will expand tonight
and could even lower with time. We are not completely sold on this
scenario, especially given the time of year, but the moisture will
hang around tonight and any amount of nocturnal cooling should
help keep the low clouds in place. Our computer models disagree on
how much clearing occurs tonight.


While thunderstorms are no longer a threat, light rain and
MVFR conditions will likely linger through most of the night. It`s
also possible the airport bounces from VFR to MVFR tonight.

MON...Mainly VFR. Chance of MVFR and -TSRA late. Winds S 5-10KT.
TUE...Mainly VFR. Chance of MVFR, -TSRA likely. Winds S 10-20KT.
WED...Mainly VFR. Chance of -SHRA. Winds W 10-20KT.


.MPX Watches/Warnings/Advisories...


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