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Area forecast discussion 
National Weather Service Twin Cities/Chanhassen Minnesota
606 am CDT Thursday Oct 23 2014

Short term...(today and tonight)
issued at 339 am CDT Thursday Oct 23 2014

Early this morning...the well advertised band of precipitation was
moving west to east through the region...and by 3am had reached
eastern Minnesota. The upper level circulation was evident on water vapor
imagery located in southern Manitoba. To the south...the
negatively tilted trough was accompanied by strong middle level
drying pushing in to western Minnesota. Skies have been rapidly clearing
across western Minnesota and that trend will continue to push east
through the morning...with the clearing line reaching the Twin
Cities around sun rise. As far as the band of precipitation is
concerned...forecast has been good so just minor tweaks to
coverage...timing essentially unchanged. The eastern half of the
forecast area will deal with this eastbound band of precipitation through the
morning...and still expect it to be east of the County Warning Area by early
afternoon.

Patchy fog has been observed this morning across parts of the
state. Dense fog was present across the extreme southwestern
corner of the state...thanks to lighter winds there. In our
forecast area...the fog has been very inconsistent...thanks to the 7-10 miles per hour
wind sustaining just enough mixing to prevent the visibility from
crashing...which it almost certainly would with this setup if not
for the wind. Updated forecast has the wind dropping a little just
prior to sunrise be prepared to see some areas of dense fog across
central Minnesota in case the wind temporarily falls below 5 miles per hour or so.

The dry air moving in from the west combined with the strong
subsidence will otherwise make for partly cloudy skies from this
afternoon through the end of the short term period. As the upper
level shortwave departs to the east...ridging and hence...anti-
cyclonic circulation will help to provide clear skies. As far as
temperatures are concerned...warmer low level temperatures on the
backside of the trough will push in and mix down. Mixing will be
deepest across the west...so looking for 70s there today. Limited
mixing and cooler low level temperatures across our east will limit highs
to the 60s in eastern Minnesota...and the upper 50s across western WI.
Temperatures tonight should fall into the 40s across the region.

Long term...(friday through wednesday)
issued at 339 am CDT Thursday Oct 23 2014

Due to a slower and less progressive development of the upper
level pattern for the end of the week into the middle of next
week...some additional temperature changes look in store for the
extended. There is high confidence that Friday will be the warmest
day of the period as a warm front will be east of the area while its
associated cold front...both attendant from an area of low pressure over
S-central Canada...will be west of the area. Zonal flow aloft
combined with low level southwesterly flow will allow highs to surge to the upper
60s in western WI to low-middle 70s in the Minnesota portion of the mpx County warning forecast area.
Temperatures will only go down from here as the cold front pushes through
late day Friday followed by a secondary cold front Friday night...the leading
edge of strong cold air advection at the surface along with northwest flow aloft with a
ridge forming over the northern plains. Noticeable drops in 850 mb
temperatures...in some areas as much as 6-8 degree c...are evident among
GFS/ec/NAM/Gem Friday into Sat which will translate to highs on Sat
ranging from 60-65 across the County warning forecast area on Sat. Though models show the
ridge aloft shifting eastward going into sun...it looks to collapse on
its way toward the Great Lakes...ending any indication of a potential
warming trend for sun into early next week. In fact...the
collapsing ridge will be followed by deep longwave troffing for
the first portion of next week. A Lee-side rockies low pressure center
will be picked up by this digging trough Monday into Tuesday...shoving
the system northeastward into the Great Lakes. Through there are some
slight variances in the storm track among the longer-term
operational models...the scenario will result in occasional rounds
of -ra late Sun night into early Tuesday morning. The additional cloud
cover combined with falling 500 mb heights will spell falling temperatures
early next week...including highs in the 50-60s Monday that will drop
to the 40s-50s Tuesday-Wednesday as cold air advection resumes behind this system.

&&

Aviation...(for the 12z tafs through 12z Friday morning)
issued at 558 am CDT Thursday Oct 23 2014

Front pushing through the eastern portion of the forecast area now...with
MVFR ceilings and showers ahead of it still to impact western WI. To
the west...fog has expanded over the last few hours...despite at
least some wind. Fog will continue to develop on the back side of
the front when skies clear given very moist low levels after the
rain overnight. Most areas should see the fog mix out by
14-15z...and should see mostly clear skies this afternoon and
tonight. Fog becomes a concern again tomorrow morning based on the
latest NAM soundings...so offered an indication there may be fog
for most taf sites. Later shifts will get a better handle on fog
potential and will likely be the primary concern of the next
issuance to come out this afternoon.

Kmsp...expecting the ceilings to linger until around 17z with some
break up beginning at 15z as area fog begins to mix out. Did not
introduce fog at msp for tomorrow morning due to lack of
confidence at this time but this will have to be considered by
later shifts.

/Outlook for kmsp/
Friday...fog possible am. Otherwise VFR. Winds south-southwest at 5-10kts.
Sat...VFR. Winds northwest at 10-15kts.
Sun...chance MVFR/-shra overnight. Winds southeast at 10-15kts.

&&

Mpx watches/warnings/advisories...
Minnesota...none.
WI...none.
&&

$$

Short term...speed
long term...jpc
aviation...speed

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