Area Forecast Discussion
Issued by NWS Twin Cities, MN

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FXUS63 KMPX 210507

Area Forecast Discussion
National Weather Service Twin Cities/Chanhassen MN
1207 AM CDT Mon May 21 2018

.SHORT TERM...(This evening through Monday)
Issued at 303 PM CDT Sun May 20 2018

Very dry northeasterly flow associated with the area of high
pressure across central MN has done a good job of suppressing the
cloud cover to extreme southern MN. However, the shortwave to our
southwest is going to lift northeast and eventually the cloud
shield will lift northward tonight.

Modest forcing for ascent will lift north with the wave tonight,
so pops increase from south to north as time goes on. The hi-res
CAMs continue to advertise the possibility of few to scattered
showers, but the uninspiring lift and moisture in addition to
fighting off the very dry antecedent airmass, did not warrant any
higher than about 30% PoPs.

The main shortwave will lift through during the day tomorrow, but
the story will remain the same. Limited omega and instability in
the latest guidance led to lowering of the PoPs and removal of
thunder mention in the forecast for tomorrow. With the upper wave
moving through, expect highs to top out in the mid to upper 60s.

.LONG TERM...(Monday night through Sunday)
Issued at 303 PM CDT Sun May 20 2018

The main concerns in the long term are the system that could bring
showers and thunderstorms Tuesday night through Wednesday.
Otherwise, the main story in the long term is the return flow
bringing warmer temperatures back into the region. Of course, an
early look ahead to next weekend as well, which could bring some
activity to the region.

Not much has changed with the forecast for Tuesday night through
Wednesday other than to slow the onset of the precip chances
slightly. With this wave, there will be some instability to work
with with deeper moisture available, but the main jet stream is
going to continue to be locked up way to our north. Shear will be
lacking during this time so while it will be possible to get a
severe storm or two, don`t expect widespread issues.

The remainder of the week looks pretty quiet but the guidance is
showing a shortwave trough moving through next weekend. Confidence
isn`t too high being so far away but it`s interesting to see the
GFS and ECMWF both showing this wave moving through on Saturday,
potentially bringing rain through as well. Again, will see how
this evolves in the coming model runs over the next several days.


.AVIATION...(For the 06Z TAFS through 06Z Monday night)
Issued at 1205 AM CDT Mon May 21 2018

MVFR cigs were along the Iowa border early this morning with
areas of IFR/LIFR cigs in central/western Iowa. As a disturbance
moves slowly across Iowa overnight, lower cigs will begin to
spread northward and lower into the MVFR range before 12z for
most of the southern one quarter of Minnesota. Eventually patchy
IFR cigs along with patchy MVFR vsbys in light showers will occur
in western, southwest/south central Minnesota. Some of the showers
will move across the rest of southern/central Minnesota, as well
as west central Wisconsin by the late morning/afternoon, but the
activity should decrease in overall coverage. The MVFR/IFR cigs
will likely hold across southern Minnesota during the
afternoon/evening, with the possibility of IFR/LIFR cigs after 6z
Tuesday. Winds will be generally from the east/southeast through
18z, and become light and variable overnight.


VFR conditions are likely through 15z, with some patches of MVFR
cigs developing after 15z. However, the normal diurnal rise in the
cigs should develop in the afternoon, with a low chance of MVFR
cigs during this TAF period. Isolated showers will be possible
from late morning, through the afternoon. However, amounts will be
less than a few hundredths of an inch. Winds will be generally
from the east/southeast through 18z, then become light and
variable overnight.


TUE...MVFR cigs early, then VFR. Wind SE 5 kts.
WED...VFR with chc SHRA/TSRA late. Wind SE 5-10 kts.
THU...VFR. Chc -TSRA. Wind S 5-10 kts.




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