Area Forecast Discussion
Issued by NWS Twin Cities, MN

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FXUS63 KMPX 232012

Area Forecast Discussion
National Weather Service Twin Cities/Chanhassen MN
312 PM CDT Sun Jul 23 2017

.SHORT TERM...(This evening through Monday)
Issued at 310 PM CDT Sun Jul 23 2017

A ridge of high pressure will move overhead tonight, and east of
the region by Monday afternoon. Patchy or areas of fog is still
forecast tonight, especially over east central and central
Minnesota, as well as west central Wisconsin as this is where most
of the precipitation has occurred in the past few days. Monday
will be similar to today but less cloud cover and slightly higher
temperatures. Humidity levels will remain low during this period.

.LONG TERM...(Monday night through Sunday)
Issued at 310 PM CDT Sun Jul 23 2017

No major changes to the extended period as the best chance of
widespread precipitation occurs Tuesday and Wednesday. Timing
remains close to previous model forecast as the bulk of the
moisture and lift occurs in northern Minnesota through Tuesday
afternoon, but as a cold front sags southward Tuesday evening,
most of central and southern Minnesota, as well as west central
Wisconsin will see showers and thunderstorms develop and spread
south and east.

As for severe weather parameters, it remains questionable on
severity due to timing of the main thunderstorm activity occurring
Tuesday night, early Wednesday. If the front slows, Wednesday
afternoon could be prime along the Iowa, Minnesota border as both
instability and wind shear values will be adequate for large hail
and damaging winds. As with previous discussions, Highs PWAT
values and the possibility of training thunderstorms Tuesday
night, could lead to flooding problems. This is mainly for areas
that has received the heaviest rainfall over the past week.

Past Wednesday, models remain consistent with a somewhat dry
period, but another cold front moving southward late next

The mean flow remains conducive for no big warm-ups or cool
periods. It will be the typical warm and humid summer in the Upper
Midwest with highs in the 80s and lows in the 60s. The highest
temperatures and humidity levels will occur in the warm sector
Tuesday afternoon. Although models have trended a bit cooler than
in previous runs, dew points rising into the 60s/lower 70s and
highs approaching or exceeding 90 degrees will lead to heat
indices of 95 to 105 degrees Tuesday afternoon. The winds will be
from the south-southwest which is a good component for downslope
conditions along the lee of the Buffalo Ridge. This area could see
highs in the mid/upper 90s if more sunshine develops.


.AVIATION...(For the 18Z TAFS through 18Z Monday afternoon)
Issued at 1238 PM CDT Sun Jul 23 2017

Deck of clouds continues to move south across MN/WI with primarily
low-end VFR ceilings. Expect ceilings to maintain these heights
and slowly rise some as the afternoon goes on. North winds of 10-15
kts will diminish towards evening, becoming calm & backing to the
east overnight. Areas of patchy fog may impact RNH & EAU towards
sunrise but otherwise expect VFR conditions Monday with
southeasterly winds

Ceilings will remain VFR through the afternoon with clouds
clearing out after 00Z. Northerly winds this afternoon
diminishing & becoming easterly overnight.

Mon...VFR. Wind SE 5 kts.
Tue...VFR. Chc TSRA. MVFR/IFR in +SHRA. Wind S-SW 10-15 kts.
Wed...VFR. Chc TSRA/SHRA early. MVFR/IFR in +TSRA. Wind NW 5-10




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