Area Forecast Discussion
Issued by NWS Twin Cities, MN

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FXUS63 KMPX 150046

Area Forecast Discussion
National Weather Service Twin Cities/Chanhassen MN
746 PM CDT Sat Oct 14 2017

.UPDATE...For 00Z Aviation discussion below


.SHORT TERM...(This evening through Sunday)
Issued at 415 PM CDT Sat Oct 14 2017

The main focus of the short term will be precipitation and how
widespread this precipitation is through the late afternoon and into
the overnight hours. Current radar is not overly impressive in terms
of echoes moving up from sw MN, reinforcing the idea that the
best coverage and more significant qpf amounts will be on the
western and northwestern fringes of our forecast area. Line of
showers extending from Mankato into central WI will continue
moving to the north. No significant shower activity is moving up
from IA. Radar trends reinforce what some of the high res models
are suggesting and that is more of an off and on sprinkles to
light showers weather event through the early evening hours before
the low pressure area currently in the central plains moves
northeast and wraps around precipitation moves in. By Sunday
morning the low will be in northern MI and all precipitation will
be out of the MN area with a few lingering showers in western WI.
Although latest model runs are indicating a faster departure of
precipitation. Skies clear rapidly Sunday morning with northeast

.LONG TERM...(Sunday night through Saturday)
Issued at 415 PM CDT Sat Oct 14 2017

The main story in the long term is the extended period of dry and
mild weather Monday through Friday. High temps in the 70s are
certainly plausible, especially in western MN beginning Tuesday,
reaching western Wisconsin by Friday. Humidity will also be on the
increase late this week.

Until then, Sunday night will be a cool night, with frost possible
across much of the region. Did mention frost for those areas
where it has not yet frosted out. Surface high will be in the
southern plains, but a ridge will extend northward into MN/WI.
There will be some gradient wind, but not much, with southwest
winds less than 5 mph.

After that, the northern jet stream will be across southern Canada
for a few days, with short waves sideswiping our area Monday night
and Wednesday. Pacific fronts with mild westerly flow will
accompany these, with surface winds generally shifting between
south and west. It is likely that the first wave will only bring
some high level clouds, but the second wave Wednesday will have a
bit more mid level moisture, enough for some mid level clouds.

The upper pattern does change somewhat during the middle and
latter part of the week. Upper level low pressure in the Canadian
High Arctic retrogrades while a strong system moves through the
Gulf of Alaska Tuesday and Wednesday. This will eventually result
in a deep trough along the west coast, while upper high pressure
builds over the central states. Models are in fairly good
agreement about this. Therefore broad southwest flow will develop
over MN/WI, and southerly winds will transport higher humidity
into the area. We could well see dew points in the mid 50s by
Friday in addition to max temps in the 70-75 range. As this
unfolds, the next chance of precip will be next Saturday. Just out
of curiosity, took a look at the GFS precipitable water, which
reaches to 1 inch Friday evening and increases to 1.5 inches
Saturday evening. ECMWF shows some decent theta-e and specific
humidity at that point as well.


.AVIATION...(For the 00Z TAFS through 00Z Sunday evening)
Issued at 747 PM CDT Sat Oct 14 2017

Occasional rain showers will persist this evening, along with
prevalent IFR ceilings for central/southern MN and west central WI
sites (KRWF/KMSP/KMKT/KRNH/KEAU).  Visibilities attendant with
the rain will generally be in the 2-4sm range. Farther north at
KAXN and KSTC, MVFR conditions will be the most common. Winds will
shift to the north/northwest with gusts into the mid/upper 20s
(knots) tonight. Precipitation wanes overnight, with VFR
conditions for Sunday (with the exception of MVFR lingering at
KEAU). Wind gusts also subside on Sunday morning, with winds
backing to the west for the afternoon.

Sub-1000ft cigs expected to prevail through 07z, then lift to
around 1500ft, becoming VFR during the start of the morning push.
Wind gusts subside by 16z.

Mon-Thu...VFR. Wind SW 5-10 kts.




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