Area Forecast Discussion
Issued by NWS Twin Cities, MN

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FXUS63 KMPX 161923

Area Forecast Discussion
National Weather Service Twin Cities/Chanhassen MN
223 PM CDT Tue May 16 2017

.Updated for 18Z Aviation Discussion...
Issued at 207 PM CDT Tue May 16 2017


.SHORT TERM...(Today and tonight)
Issued at 320 AM CDT Tue May 16 2017

The warm front of recent interest stretches from southeastern South
Dakota across southern Minnesota and west central Wisconsin.
Scattered showers and thunderstorms will continue early this morning
with much of the area in the zone of isentropic upglide north of the
aforementioned front. Could see a few of these flare up to produce
hail early this morning with the low level jet around 50+ knots as a
shortwave trough lifts into southwestern Minnesota. Updrafts are
somewhat elevated so the severe threat is limited, but mid-level
lapse rates around 7.5-8C and decent MUCAPE values will support a
small chance this morning.

Convection should diminish throughout the mid to late morning hours,
although the far northern part of the forecast area (central MN into
northern WI) could see lingering activity. The majority of the area
will see a break in activity during the afternoon, with the next
tricky part of the forecast being temperatures. Today will be warmer
given the location of the front (with much of the area in the warm
sector), and considering convection will diminish in time to allow
for recovery of the airmass. Expect low to mid 80s south of I-94
(nearing upper 80s along the IA border), with upper 70s to around 80
north of I-94.

By evening, expect thunderstorms to fire along and ahead of the cold
front, roughly along I-35 and eastward into WI. These storms will
still be capable of hail, gusty winds and brief heavy downpours
(with PWATs still around 1.5 inches). Expect heavy rainfall to
become more widespread tonight as more organized forcing from
shortwave energy lifts into the area.

.LONG TERM...(Wednesday through Monday)
Issued at 330 AM CDT Tue May 16 2017

Wednesday will be turning cooler as a frontal boundary moves
across the area. Locally heavy rainfall will occur as a secondary
surge of upper level energy moves northeast across the Upper

An abrupt change to the warm/mild air mass overhead will occur as
Wednesday system moves northeast of the region. This change will
be notable as dew points fall from the 60s, into the 20s/30s by
Thursday morning.

The mean upper air pattern will slowly transition to
northwesterly flow by late in the weekend. However, additional
chances of precipitation will occur, especially Friday afternoon,
through Saturday afternoon as another upper level storm system
moves from the desert southwest, into the Upper Midwest.

More scattered showers will occur late Sunday/Monday as the
north/northwest flow aloft will lead to additional short waves
moving southeast across the region. Overall, the short term
warm/mild period will change to much cooler and but remain
unsettled for the end of the week, and into early next week.


.AVIATION...(For the 18Z TAFS through 18Z Wednesday afternoon)
Issued at 207 PM CDT Tue May 16 2017

VFR conditions this afternoon, with showers and thunderstorms
developing later this evening across southeast MN and western WI.
These thunderstorms could produce heavy rain, but as of now it
appears they will be south and east of most taf sites. The storms
will lift northeast Wednesday morning, with MVFR/IFR ceilings
developing. Another area of rain will develop on Wednesday along
a line from Redwood Falls through St Cloud.

VFR conditions today with showers and thunderstorm chances
increasing later this evening and overnight. The heaviest rain
should be south and east of KMSP. Cloud bases should lower
overnight and be below 1700 ft tomorrow with rain likely.

Thu...VFR with MVFR/-SHRA possible early. Wind N at 10G15kt
Fri...VFR with MVFR/-TSRA possible. Wind NE at 10kt
Sat...MVFR/RA with IFR possible. Wind E at 10G20kt




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