Area Forecast Discussion
Issued by NWS Twin Cities, MN

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FXUS63 KMPX 150805

Area Forecast Discussion
National Weather Service Twin Cities/Chanhassen MN
305 AM CDT Sat Jul 15 2017

.SHORT TERM...(Today and tonight)
Issued at 258 AM CDT Sat Jul 15 2017

The short term concern is timing of front and possible convection
along boundary for the afternoon.

Water vapor imagery showing last of the last evening Dakotas
convection spilling high clouds over the state. This will be the
trend through the morning with some dissipation expected. Very
warm and humid conditions will be found across much of the area
for the afternoon. Heat indices should top out in the upper 90s
into southern central MN. The surface cold front has moved into
northwest MN at this time and should move to KRPD-KMSP-KULM line
by 19z. We should see widely scattered convection develop along
the boundary mainly to the east, but may work into the far east
metro late afternoon. We will maintain the small chance for the
front as it moves through. Instability and shear do look good
enough for possible severe storm development as well, with
hail/strong winds the main threat. SPC`s Day 1 outlook looks good.

Any thunder threat should exit to the southeast of the cwa by 01z-
02z this evening. Clearing and some drying should take place
behind the front overnight.

.LONG TERM...(Sunday through Friday)
Issued at 258 AM CDT Sat Jul 15 2017

Sunday and Monday...The start of next week will be characterized
as warm and dry due to incoming surface high pressure along with
upper level ridging. Sunday will see high pressure dropping in
from Canada behind a departing cold front while upper level flow
is out of the northwest. This combination will cause cooler
temperatures (albeit still mild) with highs dropping to around 80
degrees and much lower humidity. However, come Monday, a large
upper level ridge axis originating from the southwest CONUS will
pass over the Upper Mississippi River Valley, resulting in a
return of highs into the upper 80s and lower 90s plus higher
humidity levels. Generally precipitation-free conditions are
still expected due to the overwhelming influence of deep high

Tuesday through Friday...A pattern change will commence Monday
night into Tuesday as the ridge axis shifts off to the east and a
more progressive zonal flow aloft develops, which is expected to
last through midweek. A Pacific-origin cold front, moving onshore
today in fact, will slowly shift across the Rockies Saturday night
through Sunday. This front will then move across the Dakotas
Monday and settle over northern Minnesota Tuesday morning. The
influx of deep southerly moisture in advance of this system, its
slow progression south across the Upper Mississippi River valley
and the passage of several upper level disturbances through the
zonal flow will spell several rounds of showers and thunderstorms
across the region Tuesday through Thursday. With PWATs approaching
2 inches, heightened instability and enhanced bulk shear with
little to no capping, there is potential for not only strong to
severe thunderstorms but also heavy rain which could cause
isolated flooding. WPC QPF increases to 1.5-2.0 inches for
Tuesday-Wednesday which raises the need to keep an eye on how this
system develops. The front will settle into southern Minnesota on
Wednesday then drop south of Minnesota & Wisconsin Thursday,
allowing high pressure to regain control over the area Friday. As
for temperatures, the lack of any airmass change through the week
will keep highs in the 80s while lows remain in the 60s. The main
changes will occur with the dewpoints, particularly in the
vicinity of the frontal passages.


.AVIATION...(For the 00Z TAFS through 00Z Saturday evening)
Issued at 950 PM CDT Fri Jul 14 2017

Thinking is similar to earlier. We`ll see some high clouds from
convection to our northwest overnight, then will await frontal
passage on Saturday. It still looks like it should come through
dry, except perhaps south and east of KMSP. Still only included a
VCSH mention for KEAU, although it`s possible KMKT could see
something as well, but there isn`t enough confidence in that given
the minimal signal seen in the guidance until things are nearly
out of our area.

KMSP...Only thing to watch will be if we`re able to get any
convection to develop Saturday afternoon, but it continues to look
that isolated activity won`t get going until south/east of KMSP.

Sunday...VFR. East wind 5 to 10 kt.
Sunday night...VFR. Southeast wind 5 to 10 kt.
Monday...VFR. South wind 10 to 20 kt.
Monday night...MVFR possible late with a chance of a
shower/thunderstorm. South wind 10 to 20 kt becoming southwest.
Tuesday...MVFR possible with a chance of showers and
thunderstorms. Southwest wind 10 to 20 kt decreasing to around 10




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