Area Forecast Discussion
Issued by NWS Twin Cities, MN

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FXUS63 KMPX 170828

Area Forecast Discussion
National Weather Service Twin Cities/Chanhassen MN
328 AM CDT Sat Jun 17 2017

.SHORT TERM...(Today and tonight)
Issued at 317 AM CDT Sat Jun 17 2017

The short term concerns convective trends today and tonight.

Overall models in general agreement in handling the overall
development of the incoming Montana short wave. Mid level showers
already working across western South Dakota. Short range hires
solutions bring this into western MN later this morning and then
to eastern MN by late afternoon. It does appear to weaken some
as it works east. The 00z NAM came in a little slower and deeper
with the short wave...with the GFS pretty similar to previous
runs. Will keep pops into categorical range out west into the
afternoon and then spread higher end likely PoPs over the area
into tonight. Most areas should see some QPF as this moves through
into tonight. Instability is not that great so will keep chance
of thunder going for now. It should be highly diurnal in nature
once it does develop...mainly to the west this afternoon and then
spreading east into the evening. Cloud cover should once again
fill in during the morning and should remain mainly cloudy into
tonight as the upper trough moves through. Temperatures will
struggle to warm through the 70s most areas today...and should
remain in the 55 to 60 degree range tonight.

.LONG TERM...(Sunday through Friday)
Issued at 317 AM CDT Sat Jun 17 2017

The period will commence with a potent cold front east of the
area, from central MI through western IN along the western Ohio
River into northern AR. Aloft, a large rotating upper level low
over western Ontario province will remain in place, with several
shortwave trough disturbances swinging around the western and
southern peripheries of the low. While fairly deep moisture will
remain in place Sunday into Sunday night, the surface influence
will shift from the departing cold front to incoming high
pressure, thus any shot at appreciable precipitation will come
from the upper level shortwaves. As such, the best chances for
precipitation will be seen in far eastern portions of the WFO MPX
coverage area, with chances diminishing going westward through MN.
This upper level low will continue to rotate in place through late
day Monday, keeping the chances for any precipitation in northern
and eastern portions of the coverage area. Thunder chances will be
fairly limited due to the lack of instability and low-level
features but non-zero owing to the upper low so have kept some
mention in the forecast.

Tuesday looks to feature dry conditions as the last of the upper
level waves will push through the region Monday night and be
followed by dry northwest flow aloft Tuesday into Tuesday night. A
weak warm-frontal feature looks to slide eastward across the
international border Wednesday, bringing isolated-at-best coverage
for precipitation Wednesday but this will be followed by a more
organized system for Thursday which looks to have not only fairly
good precipitation coverage but also an uptick in instability due
to the area being warm-sectored before the system`s arrival and
some modest upper level support as flow transitions from zonal to
having a lagging upper level low moving through the region by
Friday morning. So, overall, not a lot of QPF by any means
(potentially only up to around a quarter inch for most of the
coverage area through the week) nor many chances for organized
thunderstorms aside from Thursday.


.AVIATION...(For the 06Z TAFS through 06Z Saturday night)
Issued at 1105 PM CDT Fri Jun 16 2017

VFR conditions thru 18z with a general light west/southwest wind.
After 18z, chance of SHRA/TSRA develops as a sharp weather
disturbance moves across Minnesota, and into western Wisconsin.
Timing and areal coverage remains the main challenge of SHRA/TSRA
but did adjust timing to more mid/late afternoon as this system
has slowed some. Winds will become more west/northwest by the end
of the taf period. There is an increasing chance of MVFR cigs
developing across central Minnesota Saturday evening and moving
southward during the overnight hours. Later shifts will need to
redefine how much coverage these lower cigs become.


No aviation concerns through 18z with timing of SHRA/TSRA mainly
after 21z. Cigs could begin to lower to MVFR after 6z/18.


Sun...VFR. Chc -SHRA. Wind NW 10-15 kts.
Mon/Tue...VFR. Wind NW 5-10 kts.




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