Area Forecast Discussion
Issued by NWS Twin Cities, MN

Home | Current Version | Previous Version | Graphics & Text | Print | Product List | Glossary Off
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50

FXUS63 KMPX 282052

Area Forecast Discussion
National Weather Service Twin Cities/Chanhassen MN
352 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 clearning takes place, most likely Sunday morning.

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 18Z TAFS through 18Z Sunday afternoon)
Issued at 107 PM CDT Sat May 28 2016

Thunderstorms are most likely over southern Minnesota into Wisconsin
this afternoon and early evening. Upper low in eastern Nebraska
was moving slowly northeast into Minnesota. Areas along and north
of the track should see mostly steady rain and frequent mvfr
ceilings. Thus have kept krwf, kaxn, and kstc in low clouds
through the taf period. There may be a bit a respite at krwf late
this afternoon, but for now, have only brought ceilings there up
to 2500 feet agl.

South of this track, there is a threat of storms this afternoon
and early evening from south central MN into WI, where there will
be some breaks in the clouds. Air mass is rather unstable but
lapse rates become somewhat poor later. Therefore have limited
mention of storms to about three hours during late afternoon. Once
low goes by later tonight, mvfr ceilings will move in.

Airfield is along a weak boundary where surface low will be
tracking later this afternoon and evening. Therefore winds will be
quite variable into the evening. Will limit thunder threat to 21z-
24z although it is possible some thunder might develop around 19z.
Right now it appears the stronger precip during 18z-21z will remain
west and southwest of kmsp but confidence is only average on this
timing. MVFR conditions will move in late tonight once the low
passes by.

Sunday night and Monday...VFR. Variable wind less than 10 knots.
Monday night and Tuesday...MVFR ceilings and visibilities expected
with a chance of showers and thunderstorms. Southeast wind 10 to
15 knots.


.MPX Watches/Warnings/Advisories...


AVIATION...TDK is the U.S. government's official web portal to all federal, state and local government web resources and services.