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000 
FXUS63 KMKX 210856
AFDMKX

Area Forecast Discussion
National Weather Service Milwaukee/Sullivan WI
256 AM CST Thu Nov 21 2019

.DISCUSSION...

Today And Tonight...Forecast Confidence Is High.

A solid area of rain will continue to move through the area into 
this morning, as the strong southwesterly low level jet continues 
to feed ample moisture into the area. Warm air advection will also
help support the rain into this morning. 

Gusty south winds should also develop during this period. Will 
continue the Lakeshore Flood Advisory for Sheboygan and Ozaukee 
Counties for this morning and early this afternoon, with gusty 
south winds and wave action that may lead to minor flooding of low
areas near the shore.

Rain associated with the main feed of moisture with the low level
jet will move to the east during the morning. The surface low is 
expected to move from north central Iowa into east central 
Wisconsin this morning. The low will bring the cold front through 
the area later this morning into middle afternoon. There should be
some differential CVA with the passing 500 mb shortwave trough 
this morning into early this afternoon. 

Mesoscale models are suggesting that more scattered activity 
should push through the area by middle morning into early 
afternoon, before ending with strong cold air advection pushing 
into the area. Continued with high PoPs into this morning, 
gradually lowering through the morning and early afternoon west to
east before ending. 

Total rainfall amounts are generally around or somewhat above the
75th percentile per model certainty, with most models fairly 
tightly clustered between 0.60 and 0.75 inches. The official 
forecast is generally 0.75 to 0.90 inches in most of the area, 
with lower amounts in the far southeast. This rainfall may lead to
some river stages rising over the next few days, with a few 
approaching flood stage.

Gusty south winds will veer northwest and remain gusty, after the
cold frontal passage later this morning into the afternoon. Mild
temperatures into this morning are expected ahead of the low and
cold front, before dropping quickly after the frontal passage and
into tonight. Lows should bottom out in the middle 20s later
tonight. 

Friday...Forecast confidence is high. 

High pressure will bring a quiet day with increasing sunshine.
Temps will be running in the 30s...below normal for the time of
year.  

Saturday through Monday...Forecast confidence is medium. 

There will be increased troughing through the region, but the bulk
of the forcing/impact will be elsewhere. We'll probably see more
clouds, but for now it looks dry with moderating temps each day. 

Tuesday and Wednesday...Forecast confidence is low. 

The GFS and the ECMWF continue to handle mid level energy kicking
out of the SW CONUS and lifting into the Great Lakes Tue-Tue night
very differently. The GFS maintains a more energetic, negatively 
tilted mid level short wave over the GL, while the EC is less 
amplified as it moves through. How this is reflected at the 
surface is significant. The GFS has been the most consistent from
run to run, showing rapid surface cyclogenesis with the low over 
KS/MO early Tuesday evolving into a deep cyclone over northern 
Lower MI by late Tuesday night. The ECMWF, on the other hand, has 
a very weak surface low tracking from Arkansas to Pennsylvania and
high pressure over southern Wisconsin during that same time. 

The ensemble mean from the GFS looks similar to the operational
run, which is significant, especially with the consistency from
run to run. The ECMWF continues to have many ensemble members
showing a decent system moving through the Great Lakes...similar
to the GFS. So, won't sway much from the idea that we'll see a 
decent low pressure system move through Tuesday into Tuesday 
night, but drying out for Wednesday. Temps overall look on the 
warmer side, so mostly rain for southern WI, or a mix of rain and 
snow. 

This is still a long way off and given the model variability, much
can change between now and then. So, remain flexible on
expectations...timing, intensity and precip type. 

Thanksgiving Day...Forecast confidence is medium. 

It looks like high pressure will be over the area, providing dry
conditions. It also looks cool with highs in the 30s. 

&&

.AVIATION(09Z TAF UPDATES)...

Rain is expected to continue moving through the area into this
morning, with the activity becoming more scattered from middle
morning into early afternoon before ending. 

Gusty south winds are expected to develop into this morning, with
winds veering northwest later this morning into the afternoon,
after the cold front and low move through the region. Low level 
wind shear conditions are expected this morning into early this 
afternoon, with 2000 foot level winds of 45 to 50 knots out of the
southwest, becoming northwest this afternoon. Gusty northwest
winds should linger into tonight, diminishing late.

Ceilings will lower from VFR/MVFR to IFR/LIFR category into this 
morning, lingering into early afternoon before rising to MVFR. 
These ceilings should then linger into early evening, before 
moving out by later tonight.

May see visibility values down to 1 to 2 miles at times with the
heavier rain into this morning, with values improving to 5 miles
or greater from middle morning into early afternoon. VFR category
is then expected later today into tonight.

&&

.MARINE...

Low pressure is expected to move northeast from north central Iowa
to north of Lake Huron today, then further to the northeast
tonight. This will bring a period of strong south to southwest winds
to Lake Michigan this morning and early this afternoon, before 
veering northwest later this afternoon and lingering tonight. 

South to southwest gales to 40 knots are expected over Lake 
Michigan this morning, before weakening somewhat this afternoon, 
before northwest gales to around 35 knots occur this evening. A
Gale Warning remains in effect for the open waters today into
tonight. High waves are expected today over the lake, shifting to
the eastern parts of the lake tonight.

A Small Craft Advisory is in effect for the nearshore waters of
Lake Michigan through tonight, for frequent gusts to 30 knots. A
few gales to 35 knots may occur. 

Lighter winds and waves are expected for Friday into Saturday, 
with high pressure to the southwest of the region. Southwest to
west winds may increase somewhat for Sunday into Monday.

&&

.MKX WATCHES/WARNINGS/ADVISORIES...
WI...Lakeshore Flood Advisory until 3 PM CST this afternoon for 
     WIZ052-060.

LM...Gale Warning until 3 AM CST Friday for LMZ080-261-362-364-366-
     563-565-567-669-671-673-675-777-779-868-870-872-874-876-878.

     Small Craft Advisory until 6 AM CST Friday for LMZ643>646.

&&

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