Area Forecast Discussion
Issued by NWS Milwaukee/Sullivan, WI

Home | Current Version | Previous Version | Graphics & Text | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
000
FXUS63 KMKX 111738
AFDMKX

Area Forecast Discussion
National Weather Service Milwaukee/Sullivan WI
1138 AM CST Thu Jan 11 2018

.UPDATE...Colder air wrapping quicker into far SW WI at the
moment so have been adjusting temps there. Meanwhile Milwaukee
broke a long standing record hitting 58 that goes back to 1880.
With slug of moisture heading northeast with mid level energy will
be watching carefully the overlap of this feature and the strong low
level cold air advection. Needless to say a tricky situation with
respect to precipitation types. Overall not a lot of changes
warranted to the thoughts of previous forecast, but will certainly
continue to evaluate the need for any further expansion of the
advisory heading into the afternoon hours.

PC

&&

.AVIATION(18Z TAFS)...IFR cigs will be prevalent with cold front.
Gusty southwest winds will turn sharply to the west and northwest
this afternoon as potent cold front moves through srn WI. Any rain
will become mixed with FZRA and some IP as low level thermal
profile cools beneath lingering warm wedge aloft. Precip changes
to light snow from late afternoon into the early evening hours as
the column sufficiently cools to support all frozen precip type.
Gusty northwest winds and drying work in pretty quick overnight
lifting ceilings to MVFR/VFR levels.

PC

&&

.PREV DISCUSSION... (Issued 926 AM CST Thu Jan 11 2018)

UPDATE...Temps falling hard not too far to our west so unseasonable
warmth to soon be a memory as influence of strong cold front
taking hold in western WI. Will leave headlines alone for now.
The timing of the band of mixed precip looks reasonable at the
moment after looking at various ptype progs and bufkit soundings.
Will continue to evaluate the trends as they play out and make any
needed adjustments to headlines as the situation warrants.

PC

MARINE...Going small craft advisory looks reasonable. The big
wind shift and temp drop still on track.

PC

PREV DISCUSSION... (Issued 607 AM CST Thu Jan 11 2018)

UPDATE...Areas of light rain developing over southern CWA as last
vestiges of upper level warm air advection pass by to the
southeast. Cold front approaching from the west, and frontal
passage timing still on track for this morning and early
afternoon. Temperatures will begin to tumble in western CWA next
couple hours. Only in the teens in northeast IA and southeast MN.
Impressive short wave over southern KS taking aim at southern WI
this afternoon. Enhanced precipitation from this disturbance over
western and northwest MO. No changes to ongoing Winter Weather
Advisory at this time.

AVIATION(12Z TAFS)...Ceilings continue to bounce between MVFR and
VFR in southern areas, but thinking ceilings should return to more
widespread MVFR or lower as areas of light rain continue to
develop across the area. Patchy fog may redevelop as winds weaken
due to approaching and passing cold front. Cold front knocking on
the door of southern WI, and previous timing still looks good.

PREV DISCUSSION... (Issued 337 AM CST Thu Jan 11 2018)

SHORT TERM...

TODAY and TONIGHT - Confidence...Medium.

Roller coaster ride of temperatures to continue as we have about
reached the pinnacle. High temperatures will be early this morning,
with steady or rapidly falling temps most of the day.

Breezy low level winds reaching surface and keeping fog at bay
despite warm, moist air over the area.  Short term guidance in good
agreement on carrying strong cold front across southern WI during
the morning and early afternoon. Freezing temperatures will lag
behind by several hours as south central WI should drop below
freezing by early afternoon and southeast WI by early evening. In
fact temperatures in south central WI may fall below 20 by early
evening. Currently the front extends across northeast IA into far
northwest WI.  Road temperatures will lag surface temperatures by
several hours, but should still fall below freezing in south central
WI by mid to late aftn.

Other concern is tight mid-level circulation located via WV imagery
over OK/KS area.  This circulation will track northeast and across
southern WI during the afternoon.  This enhanced synoptic lift will
coincide with low level temperatures falling below freezing and
produce a more significant area of sleet and freezing rain.  Several
hundredths up to a a tenth of an inch of glaze will be possible.
Hence per coordination with DVN and LOT, wl post Winter Weather
Advisory for much of south central WI this afternoon into the
evening, as the wintery mix will likely interfere with the late day
commute.  Mid-level short wave lags well behind sfc front and passes
through southern WI during the evening.  Lingering low to mid level
rh begins to tap into better dendritic growth zone during the late
aftn and eve.  Will hang on to higher pops during a few hours in the
evening.  Wind chills fall to 0 to 10 below late tonight.

LONG TERM...

Friday and Saturday...Forecast confidence is high:

It will be dry Friday under high pressure, with high temps 25 to
30 degrees colder than today.

Went mainly dry then Friday night and Saturday, which is a change
from the forecast for the last several days. Models have come
into good agreement for this period, suggesting that the lower
level wind flow will be northerly over Lake Michigan, which should
keep most or all of the lake effect snow offshore. Even colder
temps are expected on Saturday.

Sunday through Wednesday...Forecast confidence is medium to high:

Models remain in good agreement in bringing low pressure through
later Sunday into Monday. Soundings look a tad milder now, which
puts more of the profile in the dendritic growth zone. The GFS has
the lowest 300 mb in the growth zone at times, which could result
in pretty high snow to liquid ratios. The latest ECMWF came in
with about twice as much liquid equivalent than the previous run,
now looking similar to the GFS. This event could hang on into
Tuesday in the east, with models showing another wave rotating
through. Additionally, there could be some lake enhancement Monday
night into Tuesday. A lot of time for things to change, but
current models suggest long duration snow totals from around 2-3
inches in the southwest to 4-5 inches northeast.

Dry weather is expected to return Wednesday as high pressure
builds into the area.

Well below normal temperatures are likely through the first half
of next week.

AVIATION (09Z TAFS)...Strong low level winds keeping fog at bay
despite warm, moist air over the area.  MVFR cigs thinning in spots
to VFR but should be temporary.  Blend of VFR and MVFR ceilings
expected this morning as scattered showers develop.  Strong cold
front will pass through this morning and early afternoon. Blustery
south winds will diminish for a time as the front moves through but
then pick up quickly from the WNW.  Surface temperatures will
plummet in the wake of the front with an expanding area of mixed
precipitation this afternoon changing to mostly -sn before ending
during the evening.

MARINE...Strong offshore winds keeping dense fog at bay over the
near shore waters.  Fog will likely return later this morning as
winds slacken to coincide with passing strong cold front.  Fog will
then lift during the afternoon as increasing west winds usher much
colder air into the area. A wintery mix is likely for several hours
late this afternoon and evening, changing to light snow or freezing
drizzle before ending.  The increasing winds and rapid drop in
temperature will cause areas of freezing spray late tonight through
Friday.

&&

.MKX WATCHES/WARNINGS/ADVISORIES...
WI...Winter Weather Advisory until 8 PM CST this evening for
     WIZ056>058-062>064-067>070.

LM...Small Craft Advisory until 3 PM CST Saturday for LMZ643>646.

&&

$$
Today/Tonight and Aviation/Marine...MBK
Friday THROUGH Wednesday...DDV



USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.