Area Forecast Discussion
Issued by NWS Twin Cities, MN

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FXUS63 KMPX 181047

Area Forecast Discussion
National Weather Service Twin Cities/Chanhassen MN
547 AM CDT Sun Jun 18 2017

.updated for 12z aviation discussion below...

.SHORT TERM...(Today and tonight)
Issued at 302 AM CDT Sun Jun 18 2017

The short term concerns are the convective trends today and

Water vapor imagery showing upper trough exiting to the east of
the area early this morning. This should end the widespread
showers through about 12z or so. Models generate some minor
instability during the day today/generally less than 500 J/kg
MUCAPE/ with the may area located to the southwest this afternoon.
Weak forcing from sheared vort traveling over the eastern
Dakotas/southwest MN should be enough to generate some showers. We
will continue isolated to scattered type PoP mention for today to
the east and west. We do expect diurnal trend into early evening.
Clouds should remain much of the day into today and into the
coming night with some partial clearing possible to the southwest.
With expected cloud cover and cooler northwest flow temepratures
will struggle to warm through the lower 70s today. Cool tonight as
well...with low temperatures in the 50s.

.LONG TERM...(Monday through Saturday)
Issued at 302 AM CDT Sun Jun 18 2017

Monday and Tuesday...The start of the workweek will commence with
a broad upper level low sitting over much of lower Ontario
province with a large ridge over the western CONUS. The surface
pattern will be fairly benign as extensive high pressure resides
over the western third of the CONUS and a large cold front
continues to sweep eastward from the Appalachians through the Deep
South. Over the Upper Mississippi River valley, aside from a few
weak surface troughs, there is nothing appreciable to guide the
local sensible weather. Thus, the nearby upper level low, with
associated shortwave trough axes rounding the western and southern
peripheries, will drive the weather for the area Monday into
Tuesday. Relatively deep moisture will remain in place which will
be just enough to allow for isolated to scattered rain showers
across the area through this period. A few weak thunderstorms are
possible but instability and lift will be rather limited. Given
this expected pattern, temperatures will be on the cool (below
normal) side to start the workweek. Highs will run in the upper
60s to lower 70s for Monday then increase a bit to the middle to
upper 70s on Tuesday.

Wednesday and Thursday...This middle-of-the-week period looks to
be the most active portion of the upcoming week. The upper level
flow will get away from the persistent northwest flow experienced
for the first few days of the week to a more zonal flow. The upper
level western ridge will flatten out while a low level southerly
flow takes hold. This will increase the deep moisture into the
region, resulting in higher dewpoints/instability for the region
let alone warmer air being ushered in. A weak surface trough will
become a more-defined warm front, which is expected to lift north
over the area late Wednesday into Thursday. Some precipitation is
expected with this front, could could potentially produce some
decent QPF along with at least general thunderstorms. Will need to
see how the wind fields evolve and its timing to see if any
strong/severe thunderstorm potential would be available. The same
could be said by the associated cold front, which is expected to
pass over the region during the day Thursday. Should there be
enough slowing of the front and clearing ahead of it, to make for
a more late-day frontal passage, then there could be some
potential for strong/severe thunderstorms. Again, there is too
much uncertainty at this point. Will keep pops in the chance
category at this time and see how the scenario evolves.
Temperatures are expected to continue their warming trend through
midweek ahead of the cold front. Highs will run from the middle
70s to the lower 80s.

Friday and Saturday...The end of the week into next weekend looks
to again be fairly benign behind the midweek cold front.
Cooler/drier high pressure will slide into the region while a
colder upper level low drops in from central Canada. This looks to
produce a fairly cloudy period with isolated to scattered rain
showers from time to time. Temperatures are again expected to drop
back to below-normal values.


.AVIATION...(For the 12Z TAFS through 12Z Monday morning)
Issued at 545 AM CDT Sun Jun 18 2017

Main rain area exiting far eastern areas now. Expect period of
mvfr cigs over west central WI and affecting a portion of southern
MN early. Any lower clouds that do develop should lift to vfr
through 17z. Then redeveloping -shra/isold -tsra will develop to
the far west and eastern areas this afternoon. Could affect
KRWF/KEAU and mentioned VCSH for now. Clouds will dissipate some
into the evening with vfr conditions through the rest of the
period. NW winds a bit gusty into the afternoon becoming becoming
light nw-w overnight.

Believe the period of MVFR cigs should remain south of the area
with redeveloping cumulus to remain vfr during the period.
Expect any shower threat will remain well west and east of the
terminal site today. Expect NW winds with some gusts to 22kts
possible into the afternoon.


Mon...VFR/Chc TSRA. Wind NW 10 kts.
Tue...VFR. Wind NW 10 kts.
Wed...VFR. Wind S 10 kts.




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