Area Forecast Discussion
Issued by NWS Twin Cities, MN

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FXUS63 KMPX 182328

Area Forecast Discussion
National Weather Service Twin Cities/Chanhassen MN
628 PM CDT WED MAY 18 2016

.SHORT TERM...(This evening through Thursday)
Issued at 356 PM CDT Wed May 18 2016

Light and variable winds coupled with temperatures in the mid 60s
to lower 70s under nearly cloudless skies spell a very pleasant
day. Mostly clear skies and light winds will continue through
tonight which may allow temperatures to drop into the upper 30s
again, especially toward central Wisconsin. Otherwise, a return
flow beginning to set up should keep temperatures in the 40s.

Low level moisture will increase on Thursday. SCT-BKN cumulus
clouds are expected and forecast soundings show weak instability
through the cloud layer. That may prove enough for an isolated
shower or two where moisture return is greatest over western

.LONG TERM...(Thursday night through Wednesday)
Issued at 356 PM CDT Wed May 18 2016

The extended period will be determined by the evolution of a very
powerful Upper Low diving southward across the Pacific northwest,
and into Great Basin over the weekend. This will shift the upper air
pattern from a weak west-northwest flow, to a more pronounced
southwest flow next week. This will lead to a warmer and unsettled
pattern. Timing of this change will be important for the ladder half
of the upcoming weekend. If this system is more progressive, a
faster and wetter period is possible by Sunday afternoon. A stronger
and deeper upper low will lead to a slower solution and a drier
weekend, especially on Sunday.

Before this system evolves, boundary layer moisture will slowly
increase, leading to some possible instability showers on Friday
afternoon. However, there is no organized shortwave or surface
features to provide the means of scattered/widespread convection. Am
leaning toward isolated showers/storms in the southwest, and west
central part of Minnesota where instability is greatest. Models do
support boundary layer dew points rising into the 50s by Sunday,
with 50s/60s next week.

Although models will likely change their orientation of the low
level jet and surface features next week, severe weather parameters
have increased enough to warrant the possibility of severe
thunderstorms. Even late in the weekend shear values are high enough
to warrant strong thunderstorms once they develop. This is based on
a very strong low level jet of 50-60 kts, along with MUCAPES of 1000-
1500 J/kg.

Another severe weather parameter (CWASP - Craven/Wiedenfeld
Aggregate Severe Parameter) also supports severe weather Sunday
night/Monday. Otherwise, a cold front will slowly move across
Minnesota Monday, before stalling with another shortwave by
midweek, leading to increasing chances of wet weather


.AVIATION...(For the 00Z TAFS through 00Z Thursday evening)
Issued at 618 PM CDT Wed May 18 2016

Cu continues to dissipate now that the sun is sinking toward the
horizon. Just high clouds moving by overnight, with light and
variable winds. The predominant direction should become
southeasterly, however.

KMSP...No additional changes.

FRI...VFR. Wind SE 5-10 kts.
SAT...VFR. Wind SE 5-10 kts.
SUN...VFR. Wind S 5-15 kts.


.MPX Watches/Warnings/Advisories...


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