Area Forecast Discussion
Issued by NWS Twin Cities, MN

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FXUS63 KMPX 161159

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

.UPDATE...For 12z Aviation discussion below


.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 12Z TAFS through 12Z Wednesday morning)
Issued at 659 AM CDT Tue May 16 2017

The bulk of the thunderstorm activity has lifted north of the TAF
sites this morning. A few showers will linger after TAF issuance,
but they will be very hit or miss. Also had some pockets of
stratus develop overnight. Expect to see gradually improvement in
cigs throughout the morning as the convection lifts to the
north/east. VFR conditions are then expected this afternoon prior
to thunderstorm redevelopment, which is expected later this
afternoon/evening. Activity will become widespread overnight.

Southeast winds become south/southwesterly on Tuesday morning
with gusts to between 25 and 30 knots developing.

A break in the storms will occur this morning with redevelopment
toward evening. Coverage will increase during the mid to late

Wed...Mainly VFR. SHRA/TSRA expected. Occasional MVFR/IFR In
SHRA/TSRA. Wind SE 5-10 kts.
Thu...Mainly VFR. Chc MVFR/-SHRA in the morning. Winds N 10-15
Fri...Mainly VFR. Chance SHRA/TSRA with MVFR. Winds NE 5-10 kts.




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