Area Forecast Discussion
Issued by NWS Twin Cities, MN

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FXUS63 KMPX 252343
AFDMPX

Area Forecast Discussion
National Weather Service Twin Cities/Chanhassen MN
643 PM CDT MON JUL 25 2016

.SHORT TERM...(This evening through Tuesday)
Issued at 305 PM CDT Mon Jul 25 2016

Tonight and Tuesday...Surface analysis this afternoon shows an
expansive area of high pressure centered over Iowa, extending across
much of the upper-middle Mississippi River Valley and Great Lakes
regions. Aloft, flow is mainly zonal from British Columbia province
through the Great Lakes, taking on west northwest to east southeast
orientation. The area of high pressure will slowly shift away to the
east tonight into tomorrow, allowing surface winds to gradually
shift from northwest today to a more southerly direction during the
day tomorrow. Though the temperature advection will be virtually
negligible due to essentially no change in 500mb heights, the low
level flow coming from the south will allow more moisture to reach
this part of the country from the Deep South. From a sensible
weather standpoint, highs will be in the 80s tomorrow as they are
today while dewpoints around 60 today will creep into middle to
upper 60s tomorrow. Clouds will also be on the increase tonight into
tomorrow on the backside of the high but ahead of an incoming cold
front sliding southeast from Ontario/Manitoba provinces and the
Dakotas. The main influence of the front will be felt beyond this
period, starting Tuesday night, since the progression of the front
is being held up by the slow exit of the surface high. This
depiction is confirmed by multiple models so have slowed the timing
of any precipitation moving into western and northern portions of
the WFO MPX coverage area. Pops have been eliminated from the
tonight period and only slowly introduced during the day tomorrow,
no higher than 30 percent. Did maintain mention of thunder since the
increase in low level instability plus early-on insolation will
enhance the prospects of convection, particularly over central MN
northward in the vicinity of the incoming front and where a small
jetlet aloft of around 30 knots will develop. Severe prospects are
fairly low but it is noted that in the SWODY2 product, a greater
area of Marginal Risk was added to the midday update.

.LONG TERM...(Tuesday night through Monday)
Issued at 305 PM CDT Mon Jul 25 2016

The longer term concern remains timing of convective chances
mainly through the work week with drying into the weekend.

Models continue the trend of moving a slow moving trough/wave
across the northern plains/midwest through the week. A cold front
is progged to drop south Tuesday night and Wednesday with the
better shot of thunder associated with this feature as it moves
through. Severe weather threat looks to be rather limited with
weak shear progged and moderate diurnally driven instability.

After Wednesday...models diverge on overall strength of this low
...with the ECMWF still trying to gradually cutoff the circulation
as it exits to the southeast of Minnesota Thursday and Friday. The
GFS handles it more progressively. We Will hold onto some small
chance pops through the period at the moment. The overall trend is
for somewhat cooler conditions through the end of the week...as
high pressure eventually follows the trough and brings in a drier
northeast to east flow to much of the area.

Warmer conditions should move in into the weekend as the trough
departs and heights begin to increase out ahead of the next front
progged to move in early next week.

&&

.AVIATION...(For the 00Z TAFS through 00Z Tuesday evening)
Issued at 638 PM CDT Mon Jul 25 2016

Quiet period ahead with widespread VFR conditions. Only concern
for precip is near AXN tomorrow but the showers look widely
scattered. Went with a prob 30 as I have doubts if we will
actually see any precip within the vicinity of that airfield.
In terms of wind, high pressure sliding off to the east will allow
westerly winds continue turning toward a southwesterly direction.
Speeds are light enough to not be an impact. Speeds will get back
up to 07-10kts tomorrow afternoon.

KMSP...Any precip will hold off until the overnight period just
beyond this TAF window late tomorrow night.

/OUTLOOK FOR KMSP/
Wed...Mainly VFR. Chance MVFR/TSRA. Winds Variable 5 kts.
Thu...Mainly VFR. Chance MVFR/TSRA. Winds NE 5 kts.
FRI...Mainly VFR. Chance MVFR/TSRA. Winds E 5 kts.

&&

.MPX Watches/Warnings/Advisories...
WI...None.
MN...None.
&&

$$

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


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