Area Forecast Discussion
Issued by NWS Twin Cities, MN

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FXUS63 KMPX 151111

Area Forecast Discussion
National Weather Service Twin Cities/Chanhassen MN
611 AM CDT Tue May 15 2018

Issued at 553 AM CDT Tue May 15 2018

Updated to include 12z aviation discussion below.


.SHORT TERM...(Today and tonight)
Issued at 330 AM CDT Tue May 15 2018

Surface analysis early this morning shows a southward-moving east-
west oriented cold front bisecting MN while moving through
northern WI. South of this front, weak winds with saturated low
levels have created dense fog issues, especially for southwestern
and south- central MN. North of this front, much drier air exists.
This drier air is steadily dropping south, helping scour out the
fog as the early morning progresses. With much of southern MN
having visibility 1/4 mile or less, have issued a Dense Fog
Advisory for much of southern MN (in collaboration with
surrounding offices). As the dry air drops south, the DFA will be
able to be cut down little by little such that by late morning, no
such additional fog problems are expected. Skies will be mainly
clear due to incoming high pressure as already shown on satellite
imagery behind the front. Even with the passage of the cold front,
only a slight decrease in highs can be expected today with max
temps in the mid-upper 70s. Clear skies will then prevail through
tonight as high pressure is maintained across the area. No
additional fog problems are expected due to much drier air in
place. Will look for lows in the mid 40s to lower 50s.

.LONG TERM...(Wednesday through Monday)
Issued at |330 AM CDT Tue May 15 2018

The long term concerns remain timing of convection with passage of
the cold front.

Wednesday should be the warmest day of the period with Thursday
not far behind. The only limiting factor for Thursday would be
and clouds and shower/thunder threat. We expect temperatures to
warm through the low/mid 80s most area Wednesday and perhaps a
degree or two cooler for Thursday with more cloud cover expected,
especially to the west. Models are indicating a possible short
wave moving across the western area Thursday. This is combination
with a front dropping into northern MN could be enough to generate
some showers in the vicinity of the front. Blended guidance gave
some small chance PoPs for this activity and we will hold onto
that threat for now.

The main threat of showers and thunderstorms arrives mainly
Friday afternoon into Saturday morning across much of the area.
PoPs were increased a tad from blended guidance Thursday night
across central areas as the front/upper trough moves through.
Precipitable water increases to around 1.5 inches so some heavier
rainfall will be possible. QPF forecast has a general one half to
around 1 inch amounts Friday night through Saturday night, which
looks pretty good. The sever weather threat remains limited with
the GFS trending a bit farther south of the area for the greatest
instability. The gradient lies just to the south of the state,
with marginal shear and MUCAPEs to near 1000 J/kg with the front.
The latest CIPS severe weather probability guidance shoes just a
10-15% chance over the far west and southwest for Day 4. With the
front exiting to the east Saturday, CIPS Day 5 is focused mainly
into southern Wisconsin.

Following the front, northwest flow aloft returns over the Great
Lakes region with another sprawling Canadian high dropping over
the area. THis will keep the are cool for the weekend but we will
return to above normal temperatures again early next week.


.AVIATION...(For the 12Z TAFS through 12Z Wednesday morning)
Issued at 553 AM CDT Tue May 15 2018

Solid VFR conditions at all TAF sites through tomorrow morning. A
cold front continues to drop south, currently over southern MN,
and dragging any remaining fog with it away from the TAF sites.
Except for few passing cirrus clouds, skies will remain clear
through tomorrow. Winds will start out relatively light from the
northeast and gradually shift to be southerly by tomorrow.

KMSP...No significant weather impacts expected. However, there
will be a prescribed burn by fire officials within Fort Snelling
just southeast of the field. It is entirely possible that aircraft
could see smoke from this burn nearby, especially if arriving 30L
or departing 12R.

Wed...VFR. Wind light and variable.
Thu...VFR. Chc -SHRA in aftn. Wind S 5-10 kts.
Fri...VFR. Chc -SHRA/-TS/MVFR late. Wind SE 5-10 kts.


MN...Dense Fog Advisory until 9 AM CDT this morning for MNZ076>078-



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