Area Forecast Discussion
Issued by NWS Twin Cities, MN

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FXUS63 KMPX 051958

Area Forecast Discussion
National Weather Service Twin Cities/Chanhassen MN
258 PM CDT Fri Jun 5 2020

.SHORT TERM...(This evening through Saturday night)
Issued at 257 PM CDT Fri Jun 5 2020

As the cold front draped from ARX to OAX continues to slowly sag
southward, skies will remain mostly clear for the MPX CWA through
tonight. Overnight lows will be in the mid-50s near the IA border
and near 50 in central MN. The aforementioned cold front will
retreat northeastward throughout Saturday in response to the
development of a surface cyclone over the High Plains. Cloud cover
will increase throughout Saturday across MN and eventually into
Wisconsin as mid-level WAA pushes over this retreating frontal
boundary. Latest CAMs and the 12z NAM are also signaling the
formation of elevated thunderstorms across eastern SD Saturday
morning in response to the WAA. This convection should form into a
cluster and push east-southeastward, reaching southwest MN by early
Saturday afternoon. CAMs suggest that the intensity of the cluster
will decrease as it travels through southern MN. However, CAMs also
hint that precipitation could become more widespread into central MN
and west-central WI Saturday afternoon and evening due to the
continued WAA.

Severe weather is expected across SD and northwestern NE Saturday
afternoon and thunderstorms that will have developed in this region
will approach western MN as a linear complex late Saturday evening.
There is a small chance that these storms could have severe hail as
there will be some elevated instability across western MN. But, as
the convective line continues eastward across MN, it will gradually
dissipate from south to north from outrunning the synoptic scale
lift. After passage of storms on Saturday night, skies should be
mostly cloudy with lows in the 60s.

.LONG TERM...(Sunday through Friday)
Issued at 257 PM CDT Fri Jun 5 2020

On Sunday a deep upper level trough across Idaho and downstream
ridging will lead to low level theta_e advection and breezy
southwest winds. This will set the stage for warm temepratures,
especially across western Minnesota closer to the H850 thermal
ridge. Forecast soundings show mixing up to H850 mb is reasonable,
so look for afternoon highs in the mid to upper 90s across western
Minnesota, while the cool air hangs on across western Wisconsin with
highs in the upper 70s to near 80.

Upper level forcing associated with the aforementioned trough will
lead to rising air and thunderstorm development. The CAPE/Shear
profiles are quite high, but the better alignment is across eastern
North Dakota and northwest Minnesota where SPC has the enhanced risk
of severe weather. Farther south and east in our forecast area we
should have the CAP hold, but this will be something to watch if a
MCS develops and shifts eastward.

Looking ahead to Monday, expect very warm temperatures (in the
absence of convection) with afternoon highs in the 90s for most
locations, along with breezy south/southwest winds. The current
forecast highs are at the 90th percentile of guidance, which does
give some pause, but the synoptic set up is favorable for a run-away
temperature day so continued with this warmer forecast.

As was discussed in the previous discussion, on Monday evening into
Tuesday the threat remains for thunderstorms to develop along a
southwest to northeast oriented surface boundary, while the steering
flow aloft remains parallel to this boundary. Factor in the
potential for near record precipitable water, and this sets the
stage for heavy rain, training thunderstorms, and even some
potential flooding. Fortunately this is currently forecast across
the drier parts of the region, but this certainly remains something
to be watched as FGEN forcing in the presence of CAPE can lead to
very high rainfall amounts and potential for flash flooding.

Eventually cooler and drier air should settle in for the latter half
of the week behind this system, and no changes were made to the
blended guidance for this time period.


.AVIATION...(For the 18Z TAFS through 18Z Saturday afternoon)
Issued at 100 PM CDT Fri Jun 5 2020

VFR conditions throughout with northerly winds becoming easterly
overnight and southeasterly on Saturday. A few high clouds will
move in from the west.


VFR conditions throughout with northerly winds becoming easterly
overnight and southeasterly on Saturday. A few high clouds will
move in from the west.


SUN...MVFR. Chc TSRA. Wind SE 15G25 kts.
MON...VFR. Wind S 10-20 kts.
TUE...VFR with -SHRA possible. Wind NW at 10G20 kts.




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