Scientific Forecaster Discussion
fxus63 kgrb 290345
Area forecast discussion
National Weather Service Green Bay WI
1045 PM CDT Wed Jun 28 2017
Updated aviation portion for 06z taf issuance
issued at 640 PM CDT Wed Jun 28 2017
Late aftn runs of hrrr showed hints of storm evolution that we are
seeing presently. Two areas of convection formed, west and south
of grb service area. Southern Bow echo will be main show, with
more scattered storms in west-central Wisconsin. Most short-term
models continue this trend with western convection gradually
weakening and southern storms staying south.
Short term...tonight and Thursday
issued at 240 PM CDT Wed Jun 28 2017
It's still tough to get a firm grasp on the severe potential late
today and this evening. Rain persists across much of the area,
though it is diminishing from the west. Mid-level dry slot is
pushing into western Wisconsin, but convection continues to fire
at the nose of the dry slot. Will stick with convective scenario
set forth in the previous afd and mid-day severe weather potential statement. Storms are likely
to develop over west-central and northwest Wisconsin during the
middle to late this afternoon, and push across the forecast area
this evening. A separate band of storms developing over southeast
Minnesota and northeast Iowa may graze the southern part of the
forecast area earlier. The late-day/evening storms will pose a
risk of damaging winds and large hail. The risk of tornadoes will
also be present, mainly with any storms near the warm front
lifting into the area.
Tapered pops down later tonight, though isolated showers could
linger well past midnight. Gusty west winds are expected Thursday.
Stuck with dry forecast for most of the area, but went with a
chance of showers across the north.
Long term...Thursday night through Wednesday
issued at 240 PM CDT Wed Jun 28 2017
The weather pattern will remain busy at least through the weekend,
though there are indications that quieter conditions will finally
occur next week. Will use a multi-model blend for much of this
Thursday night through Saturday...conditions will start out quiet on
Thursday night as weak high pressure will initially be present. But
will then see clouds increase late when low pressure moves into
Iowa. With lift increasing ahead of the low, showers could push
into central and east-central WI by sunrise. The models are
trending weaker and further south with the system for Friday.
Scattered light showers will remain possible, but heavier rainfall
looks to occur south of the area. Will keep a slight chance of
thunderstorms across the southern 2 rows of counties, though not
confident that thunderstorms will reach this far north. Skies should
partially clear behind the system for late Friday night into
Saturday morning. However, upper troughing will remain overhead,
which should lead to scattered showers and isolated storms popping
up with heating on Saturday. No significant changes to temps.
Rest of the forecast...Sunday is looking like the better day of the
weekend. A shortwave trough will be dropping southeast across the
Lake Superior region and most likely will not have much impact on
our sensible weather. However, it could provide a few showers to
the region on Sunday night as it pushes a cold front south over the
state. As it stands now, early to middle of next week looks
relatively quiet with high pressure in control.
Aviation...for 06z taf issuance
issued at 1044 PM CDT Wed Jun 28 2017
Scattered showers, isolated thunderstorm still possible ahead of
cold front, but main activity will remain south of forecast area.
Occasional IFR ceilings overnight with moist atmosphere ahead of
front, but improving conditions after 12z.
beach hazards statement until 10 am CDT Thursday for wiz022-040-