Area Forecast Discussion
Issued by NWS Twin Cities, MN
FXUS63 KMPX 251124
Area Forecast Discussion
National Weather Service Twin Cities/Chanhassen MN
624 AM CDT TUE OCT 25 2016
.UPDATE...For 12z Aviation discussion below
.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 12Z TAFS through 12Z Wednesday morning)
Issued at 625 AM CDT Tue Oct 25 2016
VFR conditions are expected through at least early afternoon, and
then rain will overspread the area from the west/southwest during
the late afternoon and evening hours. MVFR then IFR conditions
will follow the onset of the rain and persist into Wednesday
morning. East/southeast winds will prevail through the period with
gusts developing for the afternoon/eve hours.
VFR today until around/after 00z Wednesday, then ceilings are
expected to lower to MVFR during the early eve as the area of rain
becomes more organized. Ceilings will then deteoriorate below
1000 ft after 06z Wed. East winds prevail through the period with
gusts to between 20 and 25 kts tonight.
/OUTLOOK FOR KMSP/
Wed...MVFR/IFR with -RA early. Wind ENE 5-10kt.
Thu...VFR. Wind VRB 5kts.
Fri...VFR. Wind S 5-15 kt.