FXUS63 KGRB 192347
AFDGRB

Area Forecast Discussion
National Weather Service Green Bay WI
647 PM CDT Tue May 19 2026

Updated aviation portion for 00Z TAF issuance

.KEY MESSAGES...

- Frost or freeze headlines may be needed Wednesday night as lows
  fall into the low to mid 30s over the Northwoods. 

- Below normal temperatures continue throughout the week, warming
  back up during the weekend.

- Scattered showers (30 to 60% chance) arrive Friday afternoon,
  lasting through Saturday.

&&

.DISCUSSION...
Issued at 1246 PM CDT Tue May 19 2026

GOES imagery and current obs show the cold front over eastern  
Wisconsin as of this afternoon, with winds having largely shifted 
to the northwest in its wake. Shower activity associated with the 
front has begun to erode as drier air feeds in from high pressure 
to the northwest. However, isolated showers will remain possible 
through this evening due to steepening lapse rates within CAA 
regime, though thunder chances will be little to none as any 
daytime instability wanes.

Rain chances... Next chance (30 to 60%) for scattered showers
arrives Friday afternoon in tandem with decent shortwave energy,
lasting through much of Saturday. Moisture influx during this 
time will be modest as we set up under marginal return flow, with 
PWATs approaching one inch Friday evening. However, most
instability looks to remain holed up to our south in proximity to
the warm front, resulting in little to no severe weather
potential. Furthermore, lack of upper-level dynamics and surface 
forcing mechanism would suggest very little thunder potential in
general. Synoptic flow then flattens out early next week before 
ridging eventually builds over much of the eastern CONUS, keeping
us mostly dry through the middle of next week.

Temperatures... Below normal post-FROPA temperatures persist
through the weekend, with highs struggling to reach 60 degrees in
some areas through the end of the work week. As high pressure 
sits and spins overhead, frost/freeze headlines may be needed at 
times as lows dip down into the low to mid 30s. Current thinking
is that Wednesday night would be the better setup for frost
development over the Northwoods due to light winds and windows 
for clearing. Tonight's frost potential seems more marginal under
mostly overcast skies, and would be confined mainly to Vilas
county regardless. As such, have opted against a Frost Advisory
for tonight. Highs then gradually moderate back to near normal by
the end of the weekend and into early next week.

&&

.AVIATION...for 00Z TAF Issuance
Issued at 647 PM CDT Tue May 19 2026

Widespread MVFR and low-end VFR clouds will remain across the area
this evening. Downsloping northwest winds will eventually help 
scatter out some of the clouds later this evening and overnight. 
Isolated-scattered sprinkles will be possible mainly across 
north-central WI early this evening, but will have no impacts to 
aviation. Additional high-end MVFR and low-end VFR clouds are 
expected on Wednesday, along with some high clouds.

West/northwest winds will continue to gust to around 20 kts this
evening, then the gusts will wane later this evening and overnight
as we lose the better daytime mixing. North winds under 10 kts are
expected on Wednesday, with a lake breeze shifting winds to the
east across eastern WI in the afternoon.

&&

.GRB WATCHES/WARNINGS/ADVISORIES...
None.

&&

$$

DISCUSSION.....Goodin
AVIATION.......Bersch