Area Forecast Discussion
Issued by NWS Twin Cities, MN

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FXUS63 KMPX 181707
AFDMPX

Area Forecast Discussion
National Weather Service Twin Cities/Chanhassen MN
1207 PM CDT Sat Mar 18 2017

.updated for 18z af discussion below...

.SHORT TERM...(Today and tonight)
Issued at 413 AM CDT Sat Mar 18 2017

A quiet short term period ahead, no precipitation is expected.
High pressure continues working in from the west, leading to
diminishing wind speeds early this morning. Meanwhile, the
amplified upper level ridge aloft will begin spreading across the
Upper Midwest.

The stratus deck covering most of the area will erode from west to
east as much drier air fills in behind the departing trough that
is currently centered over the Great Lakes. Partly cloudy to sunny
skies are expected by this afternoon and temperatures should
reach the low to mid 40s, going a few degrees higher than the
guidance consensus. Northwest winds will gradually decrease and
become calm by this evening, before a light southerly wind
develops tonight from west to east (on the back side of the
surface high).

.LONG TERM...(Sunday through Friday)
Issued at 413 AM CDT Sat Mar 18 2017

Sunday through Tuesday...Models have finally come around such that
a dry first portion of the week can be advertised. The period will
start out with a ridge axis atop the region with a warm front
having moved through the region. The combination of increased
H7-H5 heights and deep southerly flow will produce noticeable
warmer temperatures. Highs will range from the mid 50s to the mid
60s. The associated cold front of this system will follow closely
behind for Sunday night into Monday, making for an increase in
cloud cover but nothing else for the WFO MPX coverage area as the
best moisture and energy will be shunted to northern MN/WI. As
such, have been able to remove PoPs for the coverage area for
Sunday night. A more northwest flow aloft combined with incoming
Canadian high pressure will induce cold air advection for both
Monday and Tuesday. While both days will feature a mix of sun and
clouds, temperatures will plummet back down to near and even below
normal levels. Highs on Monday around 50 will drop to around 40 on
Tuesday.

Wednesday through Friday...Attention is still drawn to a Colorado
low pressure system developing on Wednesday which is expected to
slowly travel to the east northeast during the second half of next
week. The scenario is still pretty similar compared to the
previous few days: the system will develop over CO/WY Wednesday
night into Thursday then move towards the Great Lakes through the
end of the week. There are still discrepancies in the track, with
the 18/00z GFS keeping the track near and north of the WFO MPX
coverage area while the 18/00z ECMWF drops the system slightly
southeast before turning more to the east-northeast, thus keeping
the track to the south of the coverage area. Given forecast
temperatures that are also both above freezing (mainly daytime)
and below freezing (mainly nighttime), this system is surely
capable of producing periods of both rain and snow, particularly
since it still shows a rather broad precipitation shield. The
precipitation now is showing more of a break in the middle as the
first part is driven by warm-frontal/isentropic precipitation
initially then followed by cold-frontal/deep low precipitation
closer to and closely following the passage of the low pressure
center itself. Given the still good agreement on the presence of
the system, have maintain pops into the 70s and 80s. But, given
the wobbling of the track and fluctuations in QPF, it is still too
early to more specifically break down when/where precipitation
will occur and of what type.

&&

.AVIATION...(For the 18Z TAFS through 18Z Sunday afternoon)
Issued at 1205 PM CDT Sat Mar 18 2017

MVFR cigs finally beginning to erode over the west...with thinning
over the east. Expect trend to continue with most area vfr by
20z. Maybe lingering an hour or two to the far east. Then a band
of mid clouds works into the area later this afternoon/evening and
whatever is left moves into western Wisconsin late. Cold front
moves east into the eastern Dakotas Sunday morning. Gradient
increases ahead of the front and should provide gusty s-se winds.
It will remain dry through 18z Sun with vfr trends.

KMSP...
MVFR cigs should clear through 20z...with vfr trend thereafter.
Some threat of showers developing into southeast MN Sunday
afternoon. Will continue to monitor this trend and mention vcsh
after 20z Sunday for now. North winds will becoming southeast this
evening and increase/become gusty late Sunday morning into the
afternoon.

/OUTLOOK FOR KMSP/
Sunday night...MVFR possible early. Wind becoming northwest
10 to 20 kt.
Monday through Tuesday...VFR. Northwest wind 10 to 20 kt
decreasing to 5 to 10 kt Tuesday.
Tuesday night...VFR. North wind 5 kt or less becoming northeast.

&&

.MPX WATCHES/WARNINGS/ADVISORIES...
WI...None.
MN...None.
&&

$$

SHORT TERM...SPD
LONG TERM...JPC
AVIATION...DWE



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