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Area forecast discussion 
National Weather Service Twin Cities/Chanhassen Minnesota
558 PM CST Thursday Jan 29 2015

Update...
issued at 542 PM CST Thursday Jan 29 2015

Updated to include 00z aviation discussion below.

&&

Short term...(this evening through friday)
issued at 402 PM CST Thursday Jan 29 2015

Clearing skies and decreasing winds will support cold temperatures
in the single digits along and northeast of I-94...and low teens
across southwest Minnesota. By morning southerly winds will
develop across the west...with a mix of sun and clouds by Friday
afternoon.

Early afternoon water vapor imagery with GFS 500mb heights and
winds shoed the southern stream trough moving onshore the Baja California.
Closer to home....subsiding air beneath northwest flow will bring
an area of surface high pressure across the upper Midwest later
tonight. Light winds an clear skies will promote radiational
cooling...so could see the typical cold spots drop below zero..but
most locations will be in the single digits...with slightly warm
temperatures to the southwest.

By Friday morning southerly winds will bring theta_e advection on
the back side of the high pressure...so should see clouds develop
throughout the day. Highs will be in the middle 30s across the
Buffalo Ridge...and middle teens over western Wisconsin where more
clouds are expected to develop.

Long term...(friday night through thursday)
issued at 402 PM CST Thursday Jan 29 2015

The long term period is generally quiet and cooler...however the
model guidance is now hinting at a potential for light snowfall
next Tuesday-Wednesday. The weekend clipper system still remains
weak...with limited moisture and is now looking slightly southwest
of previous runs.

Starting out Friday evening we'll be on the back side of a high
with a northern stream wave sliding east through southern
Canada. We'll also be along the interface of cloud cover from this
northern wave. Cold air advection will ensue as the system to our
north moves east...so high temperatures on Saturday will only warm
up about 5 degrees during the day.

On Saturday night attention turns to yet another northern stream
wave...this one though will take a more southerly track through
Montana and South Dakota. The upper level jet streak to our west
at this time looks to be further west...keeping the best upper
level divergence from eastern South Dakota through extreme
southwestern and southern Minnesota. Probability of precipitation remain in place
there...but have trimmed them further north. The European model (ecmwf) held on to
a more northerly solution...but a strong surface high with cold
and dry Canadian air will be on the heels of this wave...which
offers higher confidence in the more southerly solution.

Both the GFS/ec are indicating a modest Pacific wave moving
through in the Tuesday-Wednesday timeframe...but being this far
out...little confidence in the timing and placement of this system
exists. It will be something to monitor.

As far as temperatures are concerned...glancing blows of Arctic
air are expected to come our way...with the GFS hinting at the
possibility of a more direct hit late next week.

&&

Aviation...(for the 00z tafs through 00z Friday evening)
issued at 542 PM CST Thursday Jan 29 2015

Able to initialize all sites with VFR...although there is a chance
some MVFR ceilings may come in-and-out of the western taf sites
during the first few hours before clouds scatter out by late
evening as high pressure moves across. Middle-and-high level clouds then
return by late morning and remain in place on the backside of the
departing high pressure tmrw afternoon and tmrw evening. Northwest winds will
settle down through the rest of the evening hours...then go light/variable around
daybreak before swinging around to southerly by tmrw afternoon with speeds at or below
10 knots.

Kmsp...VFR throughout with no significant impacts expeceted. Broken skies
early on will scatter out through this evening...even becoming clear
overnight...followed by midlvl clouds returning Thursday.

/Outlook for kmsp/
Sat...VFR with MVFR ceilings/-sn possible Sat night. Wind north at 5-10kt.
Sun...VFR with MVFR ceilings possible early. Wind north at 10 knots.
Monday...VFR with MVFR/snow possible late. Winds S at 10g15kt.

&&

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

$$

Update...jpc
short term...jrb
long term...speed
aviation...jpc

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