Area Forecast Discussion
Issued by NWS Milwaukee/Sullivan, WI
FXUS63 KMKX 202026
Area Forecast Discussion
National Weather Service Milwaukee/Sullivan WI
326 PM CDT Thu Apr 20 2017
TONIGHT AND FRIDAY...Forecast confidence is high.
Low pressure will continue to push out of the region. The cold
front associated with the low pushed through the CWA this afternoon,
and we are firmly entrenched in CAA. There is an expansive area of
clouds well upstream on the backside of the low, stretching across
all of WI and into much of MN.
Models are generally doing a good job depicting the ample low level
moisture upstream. Model consensus shows clouds lingering through
the night before gradually clearing tomorrow as the low pushes
completely out of the region. Winds will veer from the west to the
north as high pressure builds in behind the low, leaving us firmly
within CAA through most of the period. The cloudy skies overnight
and clearing afternoon skies should balance out the CAA, leaving us
with near normal temperatures.
Friday night through Monday...Forecast confidence is high:
High pressure will be in place for the weekend into early next
week, bringing plenty of sunshine and mainly above normal
temperatures. It will be cooler near Lake Michigan through this
period due to onshore winds.
Monday night through Thursday...Forecast confidence is medium:
The pattern is expected to become active again Monday night
through mid week as multiple low pressure systems move through the
region. Models are in decent agreement in targeting Monday night,
Tuesday night, and Thursday/Thursday night as the best chance for
showers. There is some variability among models though, so these
rain periods are not set in stone. Could see little thunder by
midweek, depending on how far north the systems go.
A blend of model solutions suggest temperatures within a few
degrees of normal through this period, though there is the
potential for warmer temps Tue based on the ECMWF and Canadian
solutions. Also, the ECMWF and GFS suggest below normal temps Thu,
though the Canadian is milder. Needless to say, there is some
uncertainty with temperatures next week.
Low pressure will continue to push off to the east, but ample low
clouds associated with the low remain well upstream of southern WI.
Models in good agreement showing the low clouds lingering at least
through the night, though there are some differences regarding
just how quickly clouds clear out Friday morning. Most guidance
keeps cigs at all TAF sites just above 2kft through the night.
That said, IFR cigs will be just to the north. At this time, I do
not expect IFR cigs to reach as far south as the TAF sites, but
given the proximity of potential IFR cigs, will have to keep an
eye on cigs through the night.
The center of the low has moved out of the area, so winds have
picked up. While gusts will fall off overnight, the pressure
gradient will remain tight, resulting in sustained winds around 10
kts through the night.
Low pressure will continue to push to the east, setting up a tight
pressure gradient and strong offshore winds across southern
Wisconsin. The strong winds look to linger a bit longer than
previously anticipated, so the SCA has been extended until 15z
LM...Small Craft Advisory until 10 AM CDT Friday for LMZ643>646.
Tonight/Friday and Aviation/Marine...BSH
Friday Night through Thursday...DDV