Area Forecast Discussion
Issued by NWS Twin Cities, MN

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FXUS63 KMPX 261943

Area Forecast Discussion
National Weather Service Twin Cities/Chanhassen MN
243 PM CDT Sun Mar 26 2017

.Updated for 18Z Aviation discussion...
Issued at 236 PM CDT Sun Mar 26 2017


.SHORT TERM...(Today and tonight)
Issued at 330 AM CDT Sun Mar 26 2017

A vertically stacked low pressure system was located along the IA/MO
border early this morning. This feature will move slowly northeast
to the central Great Lakes by Monday morning. A mid level
deformation zone extends northward from the low, stretching from
southwest MN through the west metro to northern WI. The deformation
zone will move a little bit farther west early this morning before
becoming stationary for the balance of the day. This zone is where
likely pops were indicated. Farther east, there will be minor short
waves rotating northwestward around the upper low aiding in bands of
light rain across the eastern FA. Chance pops were indicated for
these areas. Rain amounts today will be light and only a few
hundredths of an inch. The clouds and precipitation will keep a lid
on high temperatures today. After seeing highs on Saturday only
reaching the lower to middle 40s with little to no rain, it`s hard
to imagine we would be warmer today. Therefore, went more 40 to 45
degrees for highs. The cooler readings are to the west of the metro
under/near the deformation zone.

For tonight, the flow aloft will become more westerly as the night
progresses due to the low moving off to our east. This will shift
the deformation zone and precipitation off to the east as well.
There will be considerable low/mid level cloudiness through the
night which should keep dense fog chances at bay considering the
light rain today/this evening. This will also help keep temperatures
up overnight with lower to middle 30s forecast.

.LONG TERM...(Monday through Saturday)
Issued at 330 AM CDT Sun Mar 26 2017

Longer term concerns remain model inconsistencies in handling
movement of troughs over the CONUS with split type flow regime.
Overall lower confidence in trend of the extended...especially in
the Wednesday/Thursday time frame.

Initially...the remnants of the upper low is forecast to move
east early Monday. Models are already having issues with how much
of an influence the secondary upper circulation now over
Colorado/New Mexico region will affect the eastern portion. We
will hold onto a small chance of light rain lingering at least
during Monday morning.

After this we should see morning sunshine and warmer temperatures
Tuesday and Wednesday ahead of the next western CONUS trough.
Temperatures win the 50s should be common. Clouds will already be
on the increase Wednesday with a chance of light rain.

The real inconsistencies arrive for the Wednesday night through
Thursday night as the GFS and ECMWF diverge on handling the
trough. The GFS still cuts it off from the northerly flow
resulting in a flatter, further south solution and keeping our
region mainly dry. The ECMWF continues to show a merging of the
northern stream trough and southern stream upper low. Moisture is
lifted north ahead of the trough and does affect the area. It is
ejected more easterly an even stronger trough moves
ashore over the west coast. What I was able to discern from the
Canadian too brings more of the southern stream
influence into the region with a better shot of at least some
rain. We will continue the middle of the row scenario...and hold
onto the chance PoP scenario for now. With more clouds
expected... temperatures will be held at bay as well...with upper
40s to lower 50s a good bet.

The upper flow pattern remains fairly active. We should see dry
conditions Saturday into between systems. Timing of
the next trough brings another chance of rain later Sunday into
early next week.


.AVIATION...(For the 18Z TAFS through 18Z Monday afternoon)
Issued at 236 PM CDT Sun Mar 26 2017

Expect MVFR conditions transitioning to VFR in western MN, with
MVFR and IFR conditions lingering in eastern Minnesota and Western
Wisconsin due to the lingering stratus that has persisted across
the region for the last few days. On Monday forecast soundings
show drier air moving into the region so should see conditions
improve to VFR across the board during the afternoon.

Ceilings have risen above 1000 ft and should continue there this
afternoon and early this evening. Later this evening forecast
models continue to bring ceilings back below 1000ft, and this
makes sense based of the trends from last night. Conditions will
approach VFR by the end of the taf late Monday afternoon.

Tue...VFR. Wind NE 5 kts.
Wed...VFR. Wind SE at 10kts.
Thu...VFR. Wind E at 10kts.




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