Area Forecast Discussion
Issued by NWS Twin Cities, MN

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FXUS63 KMPX 251828

Area Forecast Discussion
National Weather Service Twin Cities/Chanhassen MN
128 PM CDT TUE OCT 25 2016

.Updated for 18Z Aviation Discussion...
Issued at 113 PM CDT Tue Oct 25 2016


.SHORT TERM...(Today and tonight)
Issued at 330 AM CDT Tue Oct 25 2016

Early morning analysis shows a developing surface trough over the
High Plains with shortwave energy taking shape over the Dakotas
ahead of an amplifying low just off the coast of the Pacific

As surface cyclogenesis ensues today over the Dakotas, warm air
advection will begin to develop ahead of the aforementioned
features. This will likely yield occasional bands of light precip in
the area, but the more formidable area of showers will arrive this
evening and tonight as the surface low advances closer to the area.
This time frame will also be the window for when thunder may be
heard, primarily over southern Minnesota closer to the low. As the
precipitation intensifies this evening, much of the area will
receive a good three quarters to one inch of rainfall between 00z
and 12z Wednesday, with amounts approaching 2 inches over south
central and southeast MN.

Regarding temperatures, highs will be a tad cooler today given the
cloud cover, with highs in the upper 40s to lower 50s. Lows won`t go
too far tonight, and should stay up near 40 to 45 for most locations.

.LONG TERM...(Wednesday through Monday)
Issued at 345 AM CDT Tue Oct 25 2016

The extended period can be characterized as progressive, but
abnormally warm due to a persistent trough across the eastern
Pacific, with ridging dominating the central part of the U.S.

Models have been trending toward a less amplified trough across
the eastern Pacific by this weekend, and into next week. In our
region, the mean ridge will likely weaken in response of the less
amplified Pacific trough and allow for more zonal flow or a
progressive pattern to develop. As with a fast zonal/progressive
flow, confidence on any one model solution is low. This is
apparent with the current out of phase solutions of the GFS/EC and
CMC. The mean pattern might be progressive, but there remains
enough uncertainty on frontal timing and location over the next
week. This also leads to models forecasting wet weather one day,
and the next model run it has it dry. Therefore, the best
possible solution is to continue a more ensemble mean flow which takes
a drier forecast for this weekend, and more unsettled next week.

Although record breaking warm temperatures are not expected in the
extended period, there remains enough confidence of abnormally
mild readings of 10 to 15 degrees above normal to continue. This
would lead to highs in the 50s/60s and lows in the 30s/40s. For
those who are looking for cooler temperatures or at least more
normal for late October, early November, it does not look likely
through the first week of November.

Models are still forecasting the AO /Arctic Oscillation/ to
remain negative through the first week of November. This is more
in line of colder outbreaks /Northern Plains/ than currently the
atmosphere is behaving. Plus, models have the PNA currently more
neutral, but current satellite and upper air analysis would
suggest a more negative phase. This current eastern Pacific
pattern leads to more ridging across the central part of the U.S.
and milder temperatures. Therefore, not until I see a significant
change in the Pacific trough will our region begin to see cooler


.AVIATION...(For the 18Z TAFS through 18Z Wednesday afternoon)
Issued at 113 PM CDT Tue Oct 25 2016

VFR conditions will gradually give way to MVFR/IFR as rains
spreads across the region and intensifies overnight. A few
thunderstorms are possible in southern MN, so included thunder
mention at KRWF. Ceilings will lower as well, and forecast
soundings show do not show any improvement on Wednesday morning.

Area of light rain will gradually fill in across the Metro, but
not expecting any visby or cig restrictions until after 00Z.
Ceilings should drop fairly quickly and go below 1700ft around
02-03Z. Ceilings will hoover around 1000ft tonight and Wednesday
with periods of light drizzle. A few thunderstorms are possible
this evening, but at this time think they will be to the south so
did not include thunder in the taf.

Thu...VFR with MVFR Cig possible. Wind VRB 5 kt.
Fri...VFR. Wind S 5-15 kt.
Sat...VFR with MVFR/-Shra possible. Wind N at 10g25 kt.


.MPX Watches/Warnings/Advisories...


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