Area Forecast Discussion
Issued by NWS Twin Cities, MN

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FXUS63 KMPX 291732

Area Forecast Discussion
National Weather Service Twin Cities/Chanhassen MN
1232 PM CDT Wed Mar 29 2017

.UPDATE...For 18Z Aviation Discussion below


.SHORT TERM...(Today and tonight)
Issued at 338 AM CDT Wed Mar 29 2017

The main short term concern is rain development today...its timing
and extent as the upper low lifts east. Temperatures today are
conditional and will be determined on how thick the higher level
clouds will be into the afternoon.

Water vapor imagery showing upper circulation remains over the
southwest/New Mexico/Texas panhandle region. Broad south to
southwest flows remains with embedded convection ahead of the
system. Models lifts this moisture northeast during the the
MN/IA border by afternoon and into the south metro by evening. We
increased likely PoPs coverage a bit farther north into the south
metro into the evening. Latest guidance had broad southeast flow
developing into the evening with 290K isentropic surface indicating
saturation developing.  We expect any precipitation to be light on
this northwest fringe of the main rain shield which will move across
the southeast portion of the cwa.

Cloud cover is expansive with convective debris for the central
plains convection transported north into the area.  This combined
with the northern stream trough should be enough to help thicken
clouds and generate the rain across mainly the eastern half of the
cwa. High temperatures today will be determined by the opaqueness
of the clouds cover...with a 60 again possible out west if the
cloud cover remains thin enough.

Colder temperatures will move into the area as the upper circulation
drifts east. This will drop thickness levels close to critical
values after 06z Thu...mainly to the far east. There could be a
rain/snow mix into a portion of west central Wisconsin then...but
little if any accumulation is expected.  QPF amounts could range
around 0.25 to 0.50 inches mainly across far south central Minnesota
during the event.

.LONG TERM...(Thursday through Tuesday)
Issued at 338 AM CDT Wed Mar 29 2017

The longer term period looks to be dominated by split flow across
the CONUS with a series of upper lows cutting off over the
southwest US, then meandering eastward with our area mainly north
of the best moisture and forcing. We`ll have some lingering light
precipitation across the southeast portion of the area early on
Thursday as the surface low moves through the Mid-Mississippi
Valley. A ridge of high pressure then looks to build in from the
north and keep things dry through Sunday. We look to get into some
weak return flow by Monday, but solutions have been trending drier
across our area with more robust large scale and convective
precipitation expected to the south with another surface low
moving from the plains through the Mississippi Valley. The ECMWF
has come more in line with a slightly more southern solution as
shown by the GFS and Canadian. Maintained some low PoPs from
Monday into Tuesday, as we could see a bit get wrung out as a weak
northern stream wave moves through the area. However, the bulk of
any significant precipitation looks to stay well to our south
during that time frame.


.AVIATION...(For the 18Z TAFS through 18Z Thursday afternoon)
Issued at 1233 PM CDT Wed Mar 29 2017

The area of rain over southern MN will continue inching north-
northeast throughout the afternoon and evening hours. Ceilings and
visibilities are expected to lower to MVFR as this occurs. KAXN
and KSTC should stay dry, but may also experience scattered MVFR
level clouds tonight. Given the light nature of the rain,
visibilities are not expected to go lower than 4SM. Some snow is
expected to mix in at KEAU overnight, but the precip should stay
liquid at other sites. Winds will be from the east/southeast at
7-11 knots, with gusts developing on Thursday.

Light rain is expected to arrive between 23z and 00z, with MVFR
ceilings possible after that through the overnight hours. The
current TAF may be a bit optimistic with the CIGS, and will need
to watch trends to see if an OVC MVFR deck looks to be prevalent
(for now have just included a TEMPO). The main window for light
rain looks to be between 00z and 08z, although drizzle cloud
linger through the morning push.

Fri...VFR. Wind NE 5-10 kts.
Sat...VFR. Wind variable less than 5 kts.
Sun...VFR. Wind SSE 5-10 kts.




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