Area Forecast Discussion
Issued by NWS Twin Cities, MN

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FXUS63 KMPX 252017

Area Forecast Discussion
National Weather Service Twin Cities/Chanhassen MN
317 PM CDT Tue Apr 25 2017

.SHORT TERM...(This evening through Wednesday)
Issued at 315 PM CDT Tue Apr 25 2017

The first wave of showers had moved northward across northern Iowa
and into southern Minnesota during the afternoon. Regional radar
did show that most of Iowa was rain free from earlier convection
this morning. However, southern Minnesota remains in the right
entrance region of the upper jet which coincides with abundant low
level moisture advecting northward. Therefore, periods of showers
will continue across most of central and southern Minnesota, and
into west central Wisconsin this evening. Once this storm system
moves from the Dakotas, northeast across northern Minnesota, and
eventually the northern part of the Great Lakes, the precipitation
will gradually taper off from south to north across southern
Minnesota. The steadier rainfall this evening will become more
scattered toward morning and slowly become more isolated by the

Forecast profiles in west central/central Minnesota late tonight
and early Wednesday does support at least a mixture of rain and
snow. However, ground temperatures remain warm and the
precipitation rate is not expected to be heavy. Thus, any snow
that falls will quickly melt, especially considering surface
temperatures will be slightly above freezing. Tomorrow will be raw
with a brisk north/northwest wind along with temperatures holding
in the 30s and 40s. Wind chill values will average in the 20s
across western and central Minnesota, with southern Minnesota, and
west central Wisconsin having wind chill values in the mid 30s.

.LONG TERM...(Wednesday night through Tuesday)
Issued at 315 PM CDT Tue Apr 25 2017

Most of the extended period, from tomorrow night through next
Tuesday, looks to be relatively quiet and chilly. The main item of
interest, which could be somewhat significant, is a storm system
which will impact the area Sunday and Monday. We may have some
lingering shower activity tomorrow night and Thursday in the wake of
the current system, and some mix with snow could certainly occur
given the cold air aloft. However, precipitation amounts will be
minimal, so no real impacts are expected.

Frost/freeze conditions could be an issue tomorrow night and
subsequent night across areas where the growing season has
started. However, things still look to be fairly cloudy tomorrow
night, which should help mitigate frost issues. So, for now, left
any mention out of the forecast, but it will certainly need
watching. After that we`ll remain under the influence of an upper
trough into the weekend as we sit along the southern periphery of
a surface high centered to our northwest over Canada. A southern
stream wave will scoot by to our south on Friday, and could bring
some light rain into the southern portion of the area. However,
the main chance of widespread and more significant precipitation
looks to arrive on Sunday as a fairly strong surface low develops
over Texas later Saturday and lifts north into Wisconsin by
Monday. The deterministic and ensemble guidance is all in fairly
good agreement with the system considering how far out in time it
is. There are certainly some differences in the details, and those
could eventually be important, particularly if we`re able to drag
more cold air southward ahead of the system, which could lead to
more in the way of snowfall (with forecast precipitation amounts
from 0.5-1.5" that would obviously be a concern). For now, will
have mostly rain in the forecast, but will mention a mix with some
snow given the uncertainty and forecast profiles that could
certainly support it depending upon which solution you consider.


.AVIATION...(For the 18Z TAFS through 18Z Wednesday afternoon)
Issued at 1215 PM CDT Tue Apr 25 2017

Low clouds/fog moved as close as the western part of the Twin
Cities metro area this morning, but started to erode as drier air
was moving southward across east central Minnesota. The rest of
west central Wisconsin remained VFR with IFR/LIFR conditions in
southwest, west central and south central Minnesota. Due to a
persistent drier flow from east central Minnesota which is evident
in satellite imagery, and models continuing their higher cigs
forecast before the precipitation develops, have lean toward a VFR
scenario for a few hrs in central/east central Minnesota, as well
as west central Wisconsin. Confidence is very high in these areas
for VFR conditions until precipitation begins, but much lower in
western Minnesota where denser cirrus and less mixing from the
drier air exists. Not too many changes past this evening as
eventually the IFR cigs will develop as the storm system moves
across the region.


A few hours of VFR conditions is expected and confidence is fairly
high on this scenario. There could be a short period of MVFR cigs
of 2.5k once the precipitation starts this afternoon. The bulk of
the lower cigs will occur after the evening rush with a stronger
north-northeast wind developing overnight. Steadier rainfall
should become more isolated by Wednesday morning, but the IFR cigs
will continue.


Thu...MVFR likely, IFR possible. Chc -RA/-SN early.
Winds N 5-15 kt bcmg light & variable.
Fri...Mainly VFR. Winds N 5-10 kt.
Sat...Mainly VFR. Winds NE 5-10 kt.




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