Area Forecast Discussion
Issued by NWS Milwaukee/Sullivan, WI
FXUS63 KMKX 180215 AAA
Area Forecast Discussion...UPDATED
National Weather Service Milwaukee/Sullivan WI
915 PM CDT MON OCT 17 2016
Watching showers developing over Portage and Waupaca counties in
a region of secondary surface moisture convergence to the south of
the main axis of surface frontogenesis with the surface low. Will
monitor to see if they will sag into the far northern counties,
as hinted by the HRRR. Will extend the slight chance PoPs another
hour or so to account for this potential.
Otherwise gusty southwest winds are the main issue with mixing in
the warm sector over southeast sections of the CWA. Seeing gusts
up to 35 MPH...with the Kenosha C-MAN reporting a gust to 35
knots (40 MPH). HWO and social media posts highlight the gusty
Warm temperatures overnight look to assure Madison will set a new
record high minimum temperature for the day, with 65F recorded at
1213 AM and forecast temperatures not dropping below 69F by 1 AM
CDT (12 midnight LST). The current record in Madison is 61F set in
1994 and 1998. Milwaukee will not set a record, with a low of 63F
at 1227 AM, one degree lower than the record of 64F set in 1998.
Will keep low-level wind shear in the TAFs until 06Z at KMSN and
between 09Z and 12Z at eastern sites until strong 50 to 60 knot
winds around 2k feet lift off to the northeast with the low
pressure currently crossing the state. VFR conditions otherwise
until a potential for MVFR cigs to move into the western CWA in
the early morning hours with a trailing cool front, crossing the
CWA between 09Z and 12Z. SREF 21Z ceiling probability forecast
only brings a 37 percent chance into South Central WI, then lowers the
probabilities to the east. Will keep cigs VFR with scattered MVFR
for now and await full 00Z forecast data.
Keeping current timing of the Small Craft Advisory, as well as
mention of a few gale force gusts from Milwaukee south to
Winthrop Harbor during the late evening and early overnight hours,as
strong winds just off the surface cross the region ahead of low
pressure tracking through central to NE WI. Winds will slowly
diminish as the stronger winds shift off to the northeast with the
.PREV DISCUSSION... /Issued 256 PM CDT MON OCT 17 2016/
TONIGHT AND TUESDAY...Forecast Confidence...Medium
Some clearing is finally working into the far southern forecast area
this afternoon. The majority of model solutions show continued
clearing into the evening...so trended sky cover that way. Could see
another round of clouds later tonight into early Tuesday morning as
the shortwave and cold front move through. Went mostly dry with this
frontal passage per the bulk of short term guidance. A brief shower
or two is not out of the question though.
Temperatures tonight will remain quite mild for mid-October through
the first part of the night, finally cooling a bit later in the
night behind the departing front. Lows will still be way above
Dry weather and decreasing clouds are expected Tuesday as high
pressure quickly builds in behind the departing low. Highs will be
cooler tomorrow, but will remain above average.
TUESDAY NIGHT AND WEDNESDAY...Forecast confidence is high.
Surface high pressure will continue to push in. An upper level
trough will be digging through the northern and central plains and
should generate some increasing mid/high clouds on Wednesday.
Still, highs on Wednesday will be above normal in the mid 60s.
WEDNESDAY NIGHT AND THURSDAY...Forecast confidence is medium.
The upper level trough will dig through the Mississippi River
valley during this period. Although most of the energy and
baroclinic forcing with this system will be located south of
Wisconsin, there is a chance for some light rain over parts of
the eastern forecast area. Some guidance is dry, while other
guidance is looking a little more wet. This period offers the
greatest uncertainty for the week ahead. We will have some deeper
uvv around here, but the column is fairly dry. But, these digging
troughs sometimes find a way to generate that light rain. A cloudy
period here with highs on Thursday in the mid to upper 50s.
FRIDAY THROUGH MONDAY...Forecast confidence is medium.
As the upper trough pushes off to the east we see very large scale
ridging build across the middle of the country, sliding across
Wisconsin over the weekend. This transition results in a period
of warm air advection between the exiting trough and the ridge
pushing in. This may generate some light showers on Friday, but
moisture will be very limited again. Overall, this period will be
dry with the coolest readings of the week on Friday, right after
the trough moves through. Then look for temps to climb back up
slowly as we head into early next week.
Finally seeing the expected clearing beginning to work into the
southern forecast area this afternoon. This trend is expected to
continue into the evening.
Models are not in great agreement with clouds tonight, so definitely
some uncertainty there. The unseasonably high moisture will linger
into tonight, but mixing will also be decent as a strong low level
jet moves through. Will see dewpoints begin to lower by late
evening, so inclined to keep the VFR forecast going for this evening
and overnight once the MVFR clouds get out of here. Could be a brief
period of lower clouds later tonight as the trough/front move
through. VFR conditions are expected on Tuesday.
Still looks like a period of low level wind shear tonight with the
May see a few showers across mainly the northwest late this
afternoon, and maybe a showers or two later tonight with the
front. Otherwise, it looks dry through Tuesday.
South/southwest winds will pick up late this afternoon and into the
evening as a strong low level jet comes overhead. A Small Craft
Advisory thus remains in effect until early Tuesday morning. Lighter
northwest winds are expected Tuesday.
LM...SMALL CRAFT ADVISORY until 7 AM CDT Tuesday for LMZ643>646.
TONIGHT/Tuesday AND AVIATION/MARINE...DDV
Tuesday NIGHT THROUGH Monday...Davis