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wi discuss

Office: MKX

FXUS63 KMKX 181042 AAA

Area Forecast Discussion...UPDATED
National Weather Service Milwaukee/Sullivan WI
542 AM CDT Thu Oct 18 2018


The forecast looks on track for today and tonight. Gusty southwest
winds are expected today. Steady warm air advection with full
sunshine should bring highs into the upper 50s. It may get a
little warmer, with the mixing from the gusty winds and daytime
heating. Lows tonight will be milder, as warm air advection
continues. Some high clouds will move into the area later tonight.



Light and variable winds early this morning will become southwest
and gusty today. Gusts of 18 to 22 knots are expected this
afternoon across the terminals. The southwest winds will remain
tonight, with gusts persisting near Lake Michigan. Did not mention
low level wind shear in TAFs for later tonight, as winds at 2000
feet look to remain below criteria.

Mostly clear skies are expected today into tonight, with some high
clouds starting to move east into the area later tonight.


.PREV DISCUSSION... (Issued 335 AM CDT THU OCT 18 2018)

TODAY and TONIGHT...Forecast Confidence - High.

High pressure to the south of the area will slide east today. Dry
conditions with mostly sunny skies are expected. Gusty southwest
winds are expected as well, with a tight pressure gradient over the
region. Steady warm air advection occurs today as well. Went above
blended model guidance for highs today, mainly in the upper 50s. It
may get a little warmer, as mixing with the winds should be fairly

Southwest winds will linger tonight, as the pressure gradient
remains fairly tight. Steady warm air advection will keep lows in
the middle 40s. Main 500 mb vorticity maximum will approach from the
west later tonight. Mesoscale models keep most of the rain showers
with this west of the area later tonight. Kept some PoPs going in
the far west, in case these showers move in sooner.

FRIDAY THROUGH SATURDAY NIGHT...Forecast...Medium to High.

Persistent southwest winds in the lower levels of the atmosphere
today and tonight will pull higher column moisture into southern WI
by Friday morning.  Current precipitable water around one quarter
inch expected to triple by the morning ahead of approaching weak
short wave trof and cold front.  These features will track west to
east across southern WI Fri afternoon and evening, likely setting
off scattered showers.  No thunder expected as little instability
despite these features moving through during peak heating. Gusty
southwest winds are expected ahead of the front, with southwest
gusts of 30 to 35 mph possible.

Still the most interesting feature affecting southern WI in the next
seven days will be a vigorous, compact mid-level short wave moving
quickly southeast across southern WI from mid-morning through mid-
afternoon.  Punch of 400mb potential vorticity with mid-level lapse
rates lowering to 6.5-8 degrees in eastern areas associated with
this feature.  Layer Q-vector convergence from GFS showing 100 units
at multiple layers.  Atmosphere also looks slightly colder as
scattered showers from this wave spreads in during the morning.  A 1-
3 hour period of strong lift in the dendritic growth zone, and a
shallow warm layer at the surface will likely result in more of
rain/snow shower mix affecting southern WI through the morning.
Visibilities may briefly drop in the snow showers, with some light
accumulation on the grass, along with gusty northwest winds.
Temperatures will likely drop into the 30s due to evaporative
cooling at precip onset contributing to the rain/snow mix. The bulk
of the rain and snow showers will end rapidly during the late
morning through mid-afternoon with clearing conditions for Saturday


SUNDAY THROUGH WEDNESDAY NIGHT...Forecast Confidence - Low to Medium.

A quiet and cool period looks likely for the end of the weekend
through early next week.  Diminishing winds and clearing skies
associated with passing high pressure will result in one of the
coldest nights of the season across southern WI Saturday night as
temperatures fall into the mid 20s to around 30 by Lake Michigan.
The high pressure will sag rapidly south of the area on Sunday.
Increasing southwest winds on its backside will allow some
modification and slightly warmer air to return to the area for early
next week. Brisk NW steering winds will carry another short wave
across the western Great Lakes on Monday afternoon and night.
Moisture will be severely limited and southern WI will only be
grazed by the synoptic lift from this system.  Hence no
precipitation is expected. The dry conditions will continue through
mid-week.  However the Medium range guidance is diverging on
Tuesday/Wednesday with regard to persistence of colder northwest
flow across the Great Lakes. ECMWF maintains colder solution with
long wave trof and low pressure lingering over eastern Canada into
the Great Lakes through mid-week. Meanwhile, GFS/Canadian solution
weaken Canadian upper low and move it off to the northern
Atlantic/eastern Canada.  This scenario results in upstream ridge
breaking down and more zonal flow spreading back into the upper
midwest.  WPC using a blend of extended guidance but leaning toward
slightly warmer GFS solution. Never the less, the bulk of the
extended period will be dry with temperatures likely near or
slightly below normal.

AVIATION(09Z TAFS)...Light and variable winds early this morning
will become southwest and gusty today. Gusts of 18 to 22 knots are
expected this afternoon across the terminals. The southwest winds
will remain tonight, with gusts persisting near Lake Michigan. Did
not mention low level wind shear in TAFs for later tonight, as winds
at 2000 feet look to remain below criteria.

Mostly clear skies are expected today into tonight, with some high
clouds starting to move east into the area later tonight.


Nearshore Waters...A Small Craft Advisory has been issued from 18Z
today until 06Z Sunday. Southwest winds 15 to 25 knots are expected
this afternoon into Friday, with gusts to 30 knots at times.

A cold front will cross the region Friday evening, with winds
shifting northwest and remaining gusty later Friday night into
Saturday evening. Gusts to 30 knots are expected at times. The
highest waves look to be toward and over the open waters of Lake
Michigan during this period.

Open Waters...The Gale Warning has been extended into Friday for the
north half of the open waters of Lake Michigan. Southwest gales to
35 knots are expected during this time, with some 40 knot gusts at
times. Winds will shift northwest Friday night and linger into
Saturday evening. Gusts may continue to reach 35 knot gales at
times. An extension of the current Gale Warning may eventually be

A Gale Warning has been issued for the south half of Lake Michigan
for Friday. Southwest gales to 35 knots are expected during this
time. After the cold front moves through Friday evening, northwest
winds may reach 35 knot gales at times into Saturday evening. An
extension of the Gale Warning may eventually be needed.


LM...Gale Warning from 7 AM to 7 PM CDT Friday for LMZ669-671-673-675.

     Small Craft Advisory from 1 PM this afternoon to 1 AM CDT Sunday
     for LMZ643>646.



Today/Tonight and Aviation/Marine...Wood
Friday THROUGH Wednesday...MBK

Office: ARX FXUS63 KARX 181056 AFDARX Area Forecast Discussion National Weather Service La Crosse WI 556 AM CDT Thu Oct 18 2018 .SHORT TERM...(Today and tonight) Issued at 309 AM CDT Thu Oct 18 2018 At 3 AM, a warm front, located west of Interstate 35 will move east across the area this morning. As this occurs, the 925 mb temperatures will quickly warm from between 2 and 7C early this morning to between 9 and 14C by late afternoon. This will allow the high temperatures to warm around 60 north of Interstate 94 and into the lower and mid 60s elsewhere. There might be even a few upper 60s along and west of the Mississippi River. Sustained southwest winds will range from 10 to 20 mph and wind gusts will range from 20 to 30 mph. A cold front will provide a chance of scattered showers as it approaches the area after midnight tonight. The saturation looks a bit better in this run, so the rain chances were increased a bit. With the sustained southwest winds remaining in the 10 to 20 mph range, the boundary layer should remain well mixed. In addition, the clouds will be increasing during the night. The combination of these two will likely slow any temperature fall, so raised the low temperatures for Friday morning by 3 to 5F. .LONG TERM...(Friday through Wednesday) Issued at 309 AM CDT Thu Oct 18 2018 With the cold front moving through the area slightly slower, raised the high temperatures by 3 to 5F over the model consensus. Currently have a morning high around 60 north of Interstate 94 and in the lower and mid 60s. This is much closer to the MOS temperatures. The rain chances also look a bit higher in this set of models, so the rain chances were increased a bit more. During the afternoon, the combination of cold air advection and subsidence will cause the sustained northwest winds to climb into the 15 to 25 mph range with winds gusts of 25 to 35 mph. From late Friday night into Saturday morning, another strong Canadian cold front will move south through the region. The precipitation chances looked far too low considering the strength of the frontogenesis, low level lapse rates, and the consistency over the last several days that this system will produce up to a tenth of an inch of QPF. Due to this, raised the precipitation chances from just 20 to 30 percent up into the 60 to 70 percent range. The highest chances look to along and east of the Mississippi River. Soundings support mainly snow across Clark and Taylor counties so went with up an inch of snow there. This snow will mainly fall on elevated and grassy surfaces. Elsewhere, there will be a mix of rain and snow. On Saturday afternoon, the sustained northwest winds will be in the 15 to 30 mph range and winds will gust into the 35 to 45 mph range. If this trend continues, a Wind Advisory may be needed. On Sunday night and Monday, another warm front will move through the region will allow temperatures to warm around 50 north of Interstate 94 and into the mid and upper 50s on Monday. && .AVIATION...(For the 12Z TAFS through 12Z Friday morning) Issued at 556 AM CDT Thu Oct 18 2018 VFR conditions will continue this period. High pressure over Illinois will drift southeast toward the Ohio River Valley through the period. The gradient between the high and an approaching cold front will produce some wind gusts of 20 to 25 knots out of the south/southwest late this morning through the afternoon. As the low level jet gets going overnight ahead of the cold front, low level wind shear will develop at both airports this evening and continue through the overnight. Some showers should develop with the low level jet as the front approaches and some of these could impact KRST late tonight so added a VCSH for that possibility. && .HYDROLOGY... Issued at 309 AM CDT Thu Oct 18 2018 River levels continue to slowly climb along the Mississippi River south of Lansing Iowa. See the latest flood statements for more details. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...None. MN...None. IA...None. && $$ SHORT TERM...Boyne LONG TERM...Boyne AVIATION...04 HYDROLOGY...Boyne
Office: GRB FXUS63 KGRB 181132 AFDGRB Area Forecast Discussion National Weather Service Green Bay WI 632 AM CDT Thu Oct 18 2018 Updated aviation portion for 12Z TAF issuance .SHORT TERM...Today...Tonight...and Friday Issued at 404 AM CDT Thu Oct 18 2018 A ridge of high pressure was centered over the region early this morning, resulting in a clear and cool morning, with temperatures in the upper teens and 20s. As the high shifts east today, southwest winds gusting to 25 to 30 mph will develop and bring a much warmer air mass into the forecast area. Sunny skies and mixing through 925 to 900 mb should yield high temperatures in the upper 50s and lower 60s in most locations. Went a couple degrees above even the warmest guidance sets, as models have exhibited a significant cold bias the past couple days. After a clear start this evening, clouds will be on the increase as a cold front approaches overnight. Though most of the night should be dry, some light showers may reach our western counties late. It will be a much milder night, with lows in the 40s. On Friday, short-wave energy, the LFQ of a jet streak and a cold frontal passage will generate some light shower activity. Temperatures may approach 60 degrees again ahead of the cold front, mainly over the southeast part of the forecast area. .LONG TERM...Friday Night Through Wednesday Issued at 404 AM CDT Thu Oct 18 2018 Expect a couple of mid level troughs to pass through the region in northwest flow aloft. This will result in below normal temperatures with generally dry conditions through early next week. The best chance for any precipitation will be on Saturday morning with the passage of a secondary cold front and mid level short wave trough. Models show strong cold advection on Saturday, so highs will be early in the day with falling temperatures thereafter. The cold air will cause rain showers to change to snow or a mix of rain and snow across much of the forecast area. Parts of north-central Wisconsin could pick up around an inch of new snow on Saturday. Some snow showers remain possible across far north-central Wisconsin Saturday night in cold cyclonic flow behind the departing mid level short wave and surface low. Surface high pressure and a weak mid level ridge in the northwest flow aloft will help to keep the area dry for the rest of the weekend. Monday looks to be a bit warmer ahead of an approaching mid level short wave and surface system. Models keep measurable precipitation well to our north with this system, so have a dry forecast going at this point. It should be a little warmer, but still colder than normal, toward the middle of next week as upper flow begins to back. && .AVIATION...for 12Z TAF Issuance Issued at 622 AM CDT Thu Oct 18 2018 Southwest winds will increase this morning, with gusts to 20 to 25 knots expected regionwide in the late morning and afternoon. Winds aloft will crank up to 45 to 55 knots this evening, resulting in a significant LLWS event through the night. Clear skies will persist into this evening, followed by increasing clouds overnight. A few showers may reach the western TAF sites late tonight, but VFR conditions should prevail. && .GRB WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM.....Kieckbusch LONG TERM......MG AVIATION.......Kieckbusch