Area Forecast Discussion
Issued by NWS Twin Cities, MN

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FXUS63 KMPX 261931
AFDMPX

Area Forecast Discussion
National Weather Service Twin Cities/Chanhassen MN
231 PM CDT Wed Jul 26 2017

.SHORT TERM...(This evening through Thursday)
Issued at 231 PM CDT Wed Jul 26 2017

Upper level ridging just west of the Rockies will build during the
next few days and our upper level flow pattern will go from a westerly
to a northwesterly pattern. Therefore we will dry out for a few
days with very typical summer time temperatures.

A cold front/wind shift/drier airmass boundary extends from
western Lake Superior to a low pressure area in central Kansas.
Showers and thunderstorms are associated ahead and along the
boundary. Behind the boundary clearing skies, northwest winds and
lower dew points are noted. As cooler air filters in this
afternoon a few scattered low clouds will form. Skies will clear
by evening in MN with scattered clouds lingering in western WI.
High pressure will continue to build overnight and Thursday. Winds
will be light and variable over eastern WI which will lead to
patchy fog. Thinking is that winds will be just enough across most
of MN to limit fog formation. A pretty strong wave moves through
Thursday afternoon coupled with steep lapse rates and as a result
will introduce chance for showers across north and east areas.
Scattered showers come to an end shortly before sunset and as the
wave moves off to the east.


.LONG TERM...(Thursday night through Wednesday)
Issued at 154 PM CDT Wed Jul 26 2017

Consistent forecast for the long term period, with essentially no
changes made from the previous shift.  The period looks relatively
quiet, and will likely see several dry days in a row for most
locations.

By tomorrow evening, there may be a fair bit of cloud cover around
as the shortwave dives southeast across Wisconsin.  Those clouds
should gradually dissipate tomorrow evening as the wave moves away
and as we lose diurnal forcing. The following couple days will be
dominated by high pressure and northwesterly flow aloft.  The same
disagreements still exist between the GFS and the ECMWF in terms of
whether we see thunderstorms develop overnight Saturday night
through Sunday.  Tend to side with the ECMWF in this scenario as
forcing for ascent is very minimal.  So, still forecasting a dry
weekend with highs in the low 80s and comfortable in terms of
humidity as dew points stay down around 60 degrees.

The ECMWF and the Canadian agree on keeping the weekend dry as well
as the first half of next week.  In fact, a quick look at the run
total QPF off the 12Z run of the ECMWF reveals that through next
Wednesday, much of our area is predicted to receive 0.00"
precipitation.  The GFS on the other hand indicates closer to an
inch of precip with a round Saturday night, Sunday night, and again
along a frontal boundary Tuesday night into Wednesday.  As of now,
tend to side with the drier ECMWF solution through the 7 days period.

&&

.AVIATION...(For the 18Z TAFS through 18Z Thursday afternoon)
Issued at 110 PM CDT Wed Jul 26 2017

A cold front/wind shift/drier airmass boundary extends from
western Lake Superior to a low pressure area in central Kansas.
Showers and thunderstorms are associated ahead and along the
boundary and will affect KRNH for the next hour as the boundary is
right at the terminal as of 18z. KEAU will see a couple more hours
of scattered RA. Behind the boundary clearing skies, northwest
winds and lower dew points are noted. As cooler air filters in
this afternoon a few scattered low clouds will form. Skies will
clear by evening in MN with scattered clouds lingering in western
WI. High pressure will build overnight and into Thursday. Winds
will be light and variable over eastern WI which will lead to
patchy fog. Believe KEAU will be the terminal we have the most fog
concerns with. KRNH will have to be monitored closely and KAXN.
Thinking is that wind will be just enough across most of MN to
limit fog formation. Confidence is not high regarding fog not
forming in these areas so will monitor terminals closely. A weak
wave moves through Thursday afternoon which will trigger scattered
clouds. No appreciable lifting mechanism to generate
precipitation. VFR to continue once front clears all terminals.

KMSP...

/OUTLOOK FOR KMSP/
Fri...VFR. Wind E 5 kts.
Sat...VFR. Wind S 5-10 kts.
Sun...VFR. Wind SW 5 kts. Scattered SHRA/TSRA.


&&

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

$$

SHORT TERM...DRL
LONG TERM...SPD
AVIATION...DRL


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