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000
FXUS63 KMKX 092109
AFDMKX

Area Forecast Discussion
National Weather Service Milwaukee/Sullivan WI
409 PM CDT Tue Apr 9 2024

.KEY MESSAGES...

- River flooding is expected to continue through at least mid
  week on portions of the Lower Fox and Rock Rivers.

- Periods of rainfall are becoming increasingly likely Thursday through
  Friday morning, which could contribute to additional rises to
  already elevated water levels on the Lower Fox and Rock
  Rivers.

- Gusty northwest winds are expected through most of Friday,
  with gales possible on the open waters of Lake Michigan.

&&

.SHORT TERM...
Issued 406 PM CDT Tue Apr 9 2024

Tonight Through Wednesday Night:

Synopsis/Mesoanalysis: Early afternoon surface obs place a cold
front to our east over the Lower Peninsula of Michigan, with west-
northwest winds firmly entrenched across southern Wisconsin. Despite
the area`s placement in the post-frontal environment, mostly sunny
skies have allowed surface temps to climb into the mid-upper 50s as
of 2:45 PM, with a scattering of stations in the Wisconsin River
Valley reporting 60+ degree readings. Positioned well upstream of
the state, mid-upper lows are evident in GOES water vapor imagery
over northwestern Alberta and the El Paso, TX vicinity. Affiliated
with the northern/southern streams of a split flow pattern
persisting across the CONUS, the two features will progress into
central portions of the continent during the short term period,
beginning to interact/phase with one another over the Mississippi
Valley by the end of the period. Surface cyclogenesis will commence
over the ArkLaTex on Wednesday afternoon, with the infant surface
low continuing to deepen as it moves into the Ohio Valley by the end
of the period. Rain chances return by early Thursday morning as DPVA
affiliated with the phasing troughs encroaches upon the region.

Wednesday: Milder high temperatures are anticipated given winds
shifting out of the southwest across the region. The afternoon
update shows readings in the mid-upper 60s across most of the area,
though a few spots in the Wisconsin River Valley could approach the
70 degree mark by late afternoon.

Wednesday Night: Rain chances increase by the predawn hours as
northern/southern stream troughs begin to interact with one another
as they converge upon the mid-upper Mississippi Valley. Highest
chances will be over the southeast, with better PoPs overspreading
all of southern Wisconsin by Thursday morning/the beginning of the
long term period (see long term).

Quigley

&&

.LONG TERM...
Issued 406 PM CDT Tue Apr 9 2024

Wednesday night through Tuesday:

Synopsis: The surface low reaching the western Ohio Valley by the
conclusion of the short term period will continue to deepen as it
progresses into Lower Michigan on Thursday. Gusty northeast winds
will become established by Thursday afternoon as the feature makes
its closest pass to the region. Gusts will increase further on
Friday as the surface low migrates toward the Hudson Bay and a ridge
of high pressure builds into the Northern Plains. Rain chances will
continue through Friday morning as northern/southern stream troughs
consolidate into a singular upper low over the Ohio Valley. Dry
conditions will prevail through the beginning of the weekend as
warmer temperatures return to southern Wisconsin. A shortwave trough
will cross the region on Sunday, with additional scattered rainfall
possible. A larger upper trough will eject into the Central Plains
early next week, supporting additional chances for showers and
potential embedded thunderstorms during the Monday-Tuesday
timeframe.

Thursday Through Predawn Friday: Periods of widespread rainfall will
overspread the region by mid-morning Thursday, with chances
continuing into the first half of Friday morning. Latest QPF
forecasts show a widespread quarter-plus inch of accumulations
across the area, with the highest totals focusing to the east of
Interstate 39. Given already elevated water levels on the Rock and
Lower Fox Rivers, the additional QPF may result in additional rises.
We will continue to monitor QPF trends over the coming forecast
cycles and make adjustments to river flood products if necessary.

Friday Morning & Afternoon: Gusty north-northwest winds are
anticipated as low pressure continues to deepen/shift into Canada.
The precise magnitude of gusts remains uncertain, given an inversion
positioned between the surface and strongest 850 millibar dynamics
in forecast soundings. Will monitor trends over the coming cycles
and make adjustments to winds/possible headlines as necessary. Given
anticipated nice weather today & tomorrow, be sure to move any
loose/lightweight outdoor furniture inside prior to the arrival of
strong winds on Friday.

Quigley

&&

.AVIATION...
Issued 406 PM CDT Tue Apr 9 2024

VFR conditions prevail through the period at all southern Wisconsin
terminals. Predominantly west-northwest winds will remain gusty at
times through this evening, with FEW to SCT fair weather cumulus
based between FL030 and FL060 possible through the remainder of peak
daytime heating. Anticipate mostly clear skies through the overnight
hours tonight, with only FEW cirrus based near FL250 expected. Winds
will gradually pivot out of the west-southwest on Wednesday as a
broad area of low pressure develops along the US-Canadian border.
Mid-upper clouds will increase nearing the conclusion of the period
as an upper disturbance approaches from the Southern Plains.

Quigley

&&

.MARINE...
Issued 406 PM CDT Tue Apr 9 2024

Generally westerly winds prevail across the open waters in the wake
of a cold front early this afternoon. Winds will gradually shift out
of the southwest from tonight through Wednesday as a broad area of
1008 mb low pressure forms along the US-Canadian border, though
gusts are expected to remain at and below 20 knots. A second,
stronger area of low pressure will develop over the southern Great
Plains on Wednesday, deepening to near 996 mb as it approaches the
Ohio River early Thursday morning. The approach of the feature will
result in a northeasterly wind shift across Lake Michigan, with
gusts between 20 and 30 knots anticipated by Thursday afternoon.
Readings will increase further Thursday night into Friday as the
aforementioned surface low deepens to near 980 mb over Lake Huron.
Widespread gusts exceeding 30 knots are expected during this time
period, with periodic gales possible on Friday morning, afternoon,
and evening. Trends will continue to be monitored over the coming
forecasts, with headlines possible should confidence continue to
increase. Gusts will begin to decrease late Friday night into
Saturday morning.

Quigley

&&

.MKX WATCHES/WARNINGS/ADVISORIES...
WI...None.
LM...None.
&&

$$

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