Area Forecast Discussion
Issued by NWS Milwaukee/Sullivan, WI
FXUS63 KMKX 270938
Area Forecast Discussion
National Weather Service Milwaukee/Sullivan WI
338 AM CST Sun Nov 27 2016
.TODAY AND TONIGHT... Forecast confidence is medium.
Light fog across southern WI will dissipate by mid morning as the
nocturnal inversion decays and southeast surface winds begin to
increase. Expect a period of sunny skies today. An area of stratus
associated with strong moisture transport, currently over MO, will
expand northeast, which should reach southern WI by late afternoon.
It won`t take long for the rain to begin once these clouds arrive.
The forcing is deep and of decent strength, with the left exit
region of the upper jet, nose of a low level jet, 500mb shortwave
trough, and warm air advection. Mesoscale models are consistent in
showing a band of rain to arrive in southwest WI by 8 pm this
evening, reach Madison by 10 pm, and Milwaukee between 11 and
midnight. The band should be out of Madison by midnight or 1 am.
Scattered showers should continue behind the main band of rain
overnight. Forcing seems sufficient, along with steep lapse rates in
the mid levels, to mention thunder with this band of rain. No severe
storms. Rainfall totals for just tonight are expected to be a half
to three quarters of an inch.
The pressure gradient is really going to tighten up over southern WI
as low pressure occludes over the Dakotas this evening. Expect
south wind gusts of 20 to 30 mph overnight.
MONDAY AND MONDAY NIGHT - Forecast Confidence...High.
The surface and upper lows become stationary over the eastern
Dakotas. There may be a break in the precip Monday morning between
shortwaves and as the core of the LLJ weakens and moves east.
Another round of precip is expected Monday afternoon and night. A
branch of the LLJ redevelops and provides another surge of moisture
into the region during this time as a shortwave rotates north across
southeast WI. Precipitation ends Tuesday morning after a surface
cold front passes through overnight.
Temperatures warm with the strong southwest flow so precip type is
easily all rain. South winds will gust 20 to 30 miles per hour
through Monday. Some models show a small amount of elevated
instability in the west but not enough to mention thunder.
TUESDAY THROUGH SUNDAY - Forecast Confidence...Medium.
The lows shifts into Minnesota then slowly meanders east by
Thursday. Drier flow should allow for some sun on Tuesday. Later in
the period cloud cover will return and there are small precip
chances at times due to weak shortwave activity and dominant
cyclonic flow. Temperatures will be slightly cooler as the upper low
hangs around and northwest flow dominates. Lows will be around 30
later in this period so there is a chance for light snow at times.
Little to no accumulation is expected.
Southerly winds will increase ahead of approaching low pressure
today. Wind gusts are expected to reach gale force by around
midnight. This looks like a low-end gale event. A gale warning is in
effect from midnight Sun night though most of Monday night. The
strong winds will build high waves, the highest in the northern
Winds will shift to the southwest Tuesday morning and gusts will
approach small craft advisory levels.
LM...GALE WARNING from midnight tonight to 3 AM CST Tuesday for
TODAY/TONIGHT AND AVIATION/MARINE...MRC
Monday THROUGH Saturday...Marquardt