Area Forecast Discussion
Issued by NWS Twin Cities, MN

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary Off
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50

FXUS63 KMPX 220726

Area Forecast Discussion
National Weather Service Twin Cities/Chanhassen MN
226 AM CDT Sun Jul 22 2018

.SHORT TERM...(Today and tonight)
Issued at 225 AM CDT Sun Jul 22 2018

Surface analysis and WV satellite imagery early this morning show
plenty of dry air over eastern MN into western WI under a crossing
upper level ridge and the southern portion of high pressure
emanating from Hudson Bay. WV imagery also shows high-level moisture
being advected into western MN from the Dakotas, not enough to cause
significant cloud cover but enough such that later on today, there
will be evident high level cirrus and potentially some CC/CS clouds
as effects of the deep ridge wane. As the day progresses and the
ridge moves away, a cold front currently over Montana into the
central Rockies will shift east, in concert with a shortwave
disturbance over the northern Rockies evident on WV imagery. This
front will move across the Dakotas today and slide into western MN
by daybreak Monday morning. Not only will the trend for having
clouds increase continue overnight into Monday morning, but the
increased lift associated with the frontal approach and slightly
deeper moisture may be enough to nudge isolated to scattered showers
into western and central MN overnight through daybreak. Not looking
for anything strong but some brief moderate-heavy downpours are

As for temperatures, a slight uptick is to be expected with a less
solid northerly flow plus an increase in dewpoints from the
southwest. Highs will hit the upper 70s and lower 80s but the main
difference will come for lows early Monday morning. Increased clouds
will keep heat from escaping overnight, allowing lows to range
through the 60s area-wide.

.LONG TERM...(Monday through Saturday)
Issued at 225 AM CDT Sun Jul 22 2018

Other than two frontal boundaries with scattered showers and storms,
there is little in the way of appreciable precipitation in the
forecast over the next week.  The weather pattern for the end of
July looks to become stagnant with slightly below normal
temperatures and dry weather.

By tomorrow morning, the Canadian upper low will be sliding east
across northern Manitoba.  Across the CONUS, an expansive upper
ridge will be in place across the western half, with a trough will
be in place across the east.  The initial frontal boundary extending
southward from the Manitoba system will reach northwestern MN by
tomorrow morning and continue southeast across MN during the day,
eventually moving through western WI by tomorrow night.  Limited in
both energy and moisture, do not expect widespread precipitation
along this front and continued to advertise PoPs mostly around 20%
for this boundary moving through.

High pressure builds in for Tuesday before a second shortwave merges
with the large Canadian trough to our north, and pivots southeast
toward the North Dakota/northern MN.  This will send a stronger
frontal boundary with more upper level support through our area
midweek.  However, there are some timing difference on when this
front pushes through, with the GFS doing so about 9 hours faster
than the ECMWF.

Following the midweek system, the upper level troughing across much
of North America will extend southward into our area, keeping the
main jet to our south to round out the week.  This will mean
northwesterly flow from Canada, and highs in the 70s likely with
dew points in the 50s.  The slightly cooler than normal and less
humid pattern looks to continue beyond the end of the long term


.AVIATION...(For the 06Z TAFS through 06Z Sunday night)
Issued at 1101 PM CDT Sat Jul 21 2018

Main change from 00z TAFs is stratus in WI is not looking to make
it as far west in WI, which means EAU will remain in the clear. It
will be VFR through the night, with only a small threat of br/fg
at AXN/STC/RWF, but potential is too low to include in the TAFs.
With high pressure passing off to the north Sunday, we`ll have
light east winds and a few-sct cu field between 3k and 5k feet.
During the afternoon, thunderstorms will develop along a cold
front in NODAK and will be heading toward AXN by the end of the
TAF period. A few of the CAMs show TS reaching AXN as early as 3z,
but that thunder will be on a decreasing trend, so will wait until
confidence increases on TS evolution into MN before brining any
mention in to the TAF.

KMSP...At the end of the period, a few of the CAMs are indicating
showers may be in the area, with the HRRR being the most
aggressive with showing showers in the area as early as 8z. This
looks overdone when looking at forcing/instability forecasts, so
have kept MSP dry and would be surprised if MSP saw anything at
all with this front coming through on Monday.

Mon...VFR. Slight Chc -TSRA. Wind vrbl bcmg NW 5-10 kts.
Tue...VFR. Wind W 5 kts.
Wed...VFR. Slight Chc -TSRA. Wind W bcmg NW 10G20 kts.




AVIATION...MPG is the U.S. government's official web portal to all federal, state and local government web resources and services.