Area Forecast Discussion
Issued by NWS Twin Cities, MN

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FXUS63 KMPX 192259

Area Forecast Discussion
National Weather Service Twin Cities/Chanhassen MN
559 PM CDT Wed Jul 19 2017

.UPDATE...For 00z Aviation discussion below


.SHORT TERM...(This evening through Thursday)
Issued at 424 PM CDT Wed Jul 19 2017

Ongoing severe MCS will exit to the southeast quickly late this
afternoon. The forecast then becomes quite uncertain for this
evening and overnight with convective redevelopment possible
across central Minnesota. The atmosphere seems to be recovering
somewhat across South Dakota and there have been a few cells over
west central MN this afternoon. The HRRR would imply an east-west
line of storms developing between 02-03Z across central MN and
progress southeast for the rest of the evening into the early
overnight hours. This activity would contain a large hail threat,
although some damaging wind gusts are also possible. The biggest
threat will be heavy rainfall with training cells, but CAMs seem
to keep the line progressing southward which would limit flash
flooding potential.

.LONG TERM...(Thursday night through Wednesday)
Issued at 445 PM CDT Wed Jul 19 2017

For the extend, we`ll see our zonal flow transition over to
northwest flow this weekend, before going back more zonal by the
middle of next week. Most concerning period looks to Thursday night
into Friday, when another round of severe weather and heavy rainfall
looks possible.

Our dry weather Thursday will be short lived as moisture quickly
returns Thursday night from Nebraska toward southwest MN. Most of
the guidance is in agreement with an elevated band of thunderstorms
working into southwest MN. This will push the warm front back into
southern MN Friday afternoon, and guidance is in good agreement on
storms firing off along this front and heading southeast toward
Chicago Friday night. Some discrepancies with how far north this,
but we followed the more southern solutions for QPF Friday, like the
GFS for Friday as what are seeing today has tracked south of even
what the southern models had. Moisture, instability, and shear
parameters all look similar to what we are seeing today, so all
modes of severe weather will be possible, but upscale growth to an
MCS looks likely, probably tracking from south central MN over
toward southern lower Michigan.

For the weekend, it is looking up weather wise, as a secondary
shortwave in the increasingly northwest low drops across northeast MN
toward the U.P. of Michigan, with the majority of activity Saturday
night into Sunday staying off to our northeast.

We`ll have dry weather to start next week, but by Tuesday, moisture
will be surging back north across the Plains, with thunderstorm
chances returning Tuesday night into Wednesday as a front works into
the area.


.AVIATION...(For the 00Z TAFS through 00Z Thursday evening)
Issued at 600 PM CDT Wed Jul 19 2017

In the wake of the showers and storms there will be a period of
benign weather, but another round of storms may develop across
central MN/WI after 03z into the overnight hours. MVFR cigs/vsbys
would be possible attendant with the storms, including patchy fog
and MVFR cigs in the wake of the precip with the warm front
stretched across the area. After daybreak Thursday clear skies
will prevail with northwest winds of 7-10 knots.

The next round of storms looks to develop around 03z, and persist
through around 07z. MVFR cigs/vsbys will be possible during that
time, and cigs around 1500 feet may linger through the morning
push. After 14z clear skies and northwest winds around 8 knots

Fri...Mainly VFR. -SHRA/TSRA likely. Winds SE 5-10 kts.
Sat...Mainly VFR. Chc MVFR in -SHRA/TSRA. Winds lgt and vrbl.
Sun...VFR. Wind NW 10 kts.




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