637 
FXUS63 KMPX 190905
AFDMPX

Area Forecast Discussion
National Weather Service Twin Cities/Chanhassen MN
405 AM CDT Thu Oct 19 2017

.SHORT TERM...(Today and tonight)
Issued at 405 AM CDT Thu Oct 19 2017

The main issue today is near critical fire weather conditions. Dew
points this morning are already quite low in the lower 30s and am not
expecting any recovery until later this afternoon across far 
western Minnesota. Deep mixing and dry air aloft will allow dew 
points to mix out into the upper 20s or lower across eastern MN 
and western WI. While dew points should be a little higher across 
western MN, temperatures will also be warmer, possibly in the 
lower 80s, which will offset the higher dew points. Min RH values 
will fall into the upper teens to mid 20s area wide today, with 
stronger winds than observed yesterday. We may have gusts of 30 to
35 mph over western MN. The only question remaining is fuel
quality, which will be assessed this morning for a possible Red
Flag Warning.

Forecasted highs continue to be several degrees above guidance. 
Due to favorable mixing, derived high temperatures by mixing to 
875 mb. 2 meter and MOS temperatures never seem to capture these
late season warm ups adequately. 

Increasing humidity levels and a steady southerly breeze will keep
temperatures from dropping too much below the mid 50s tonight. 

.LONG TERM...(Friday through Wednesday)
Issued at 405 AM CDT Thu Oct 19 2017

Confidence remains high for Friday and Saturday forecast as the mean 
progressive upper level flow begins to transition to a more 
amplified/blocking pattern next week. 

First, models have been consistent on the evolution of a long wave 
trough moving inland across the Pacific Northwest, Rockies and into 
the Plains by Saturday. Embedded short waves, a cold front and 
return moisture from the Gulf of Mexico, will lead to an increasing 
chance of precipitation Saturday. The increasingly amplified pattern 
should also support upper jet energy for widespread precipitation. 
Timing is the only factor that remains questionable, but cold 
frontal passage should be Saturday afternoon in western Minnesota, 
and Saturday evening in eastern Minnesota. 

Ahead of this system, and due to the support of jet energy, surface 
winds will be strong. Gusts of 30 to 40 mph look reasonable Friday 
along with temperatures approaching record highs. Model guidance has 
been consistently too cool on the temperatures Friday afternoon, and 
even tonights run, guidance readings are 5 degrees too cool. As with 
previous forecast, used a mix down process that supports highs in 
the upper 70s, to around 80 degrees across the Upper Midwest. 

As models converge on this amplified pattern developing, questions 
remain on the southern jet core becoming split from the main upper 
flow. This allows for a storm system to form in the southern Plains 
late in the weekend, and into early next week. Although models 
support this split flow regime, consensus on where and how strong 
this storm system becomes is low. The EC/GEM/GFS all support a 
cutoff upper low forming over the eastern half of the nation next 
week, but differences arise on the strength of the surface low and 
the depth of the cutoff system. In addition, the northern stream of 
the jet core begins to interact with the southern stream. This will 
make for a lot of uncertainty in the forecast, and likely 
differences from run to run deterministic solutions. The best 
scenario is to convey the uncertainty, highlight the potential of a 
strong storm system next week, and continue the trend of colder 
temperatures.

&&

.AVIATION...(For the 06Z TAFS through 06Z Thursday night)
Issued at 1020 PM CDT Wed Oct 18 2017

High confidence in VFR conditions throughout this TAF set with
only passing high clouds, if anything at all. Main issue will be
wind directions with the departing front followed by warm
sectoring ahead of the next front for Saturday. Will look for
winds to remain WNW into the overnight hours then back to 
southerly by daybreak tomorrow then have breezy speeds tomorrow 
afternoon.

KMSP...No significant issues outside of the wind directions. Could
see some winds near 220 with speeds in the 4-5 kt area during the
morning push tomorrow but winds will mainly be light/variable
before becoming solidly southerly by midday.

/OUTLOOK FOR KMSP/
Fri...VFR. Winds S 10-15G25 kts. 
Sat...Mainly VFR. Chance of TSRA/MVFR in aftn. Winds S bcmg W 
10-15 kts. 
Sun...VFR. Winds W 5-10 kts.

&&

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

$$

SHORT TERM...BORGHOFF
LONG TERM...JLT
AVIATION...JPC