FXUS63 KGRB 191902

AFDGRB



Area Forecast Discussion

National Weather Service Green Bay WI

202 PM CDT Thu Mar 19 2026



Forecast discussion for routine afternoon forecast issuance



.KEY MESSAGES...



- Wintry mix tonight near the Michigan border. Minimal snow and 

  ice accumulation expected. 



- Areas of fog tonight into Friday morning central to north- 

  central WI. 



- Next chance of a wintry mix and snow (30-50%) Saturday night

  into Sunday, especially over northern WI.  



- Temperatures surging above normal into Saturday, with the warmth

  peaking Saturday (mid to upper 50s). Snowmelt and increased

  flows and rising levels on rivers and streams are expected.

  Several rivers may reach bankfull or even minor flood stage

  beginning this weekend.



&&



.DISCUSSION...

Issued at 201 PM CDT Thu Mar 19 2026



NW flow will bring a couple of clipper systems to the region. The

first occurs tonight into Friday morning with a smattering of

light rain, snow and possible freezing rain near the immediate

border with Upper Michigan. Ice and snow accumulations look

minimal and sfc temps will be at or above freezing. Thus, impacts

look to be on the lower side. Late tonight into Friday, the

ongoing melting snow and warmer temps/dewpoints will support areas

of fog developing over central and north-central WI. Fog could be

locally dense. Given low temps remaining above freezing, roads

that are now clear of recent snow cover should just stay wet.



Friday will feature warmer temperatures as highs reach the 40s 

across the Fox Valley and lakeshore, with around 50 across central

and north-central Wisconsin. A low pressure system developing 

over the Plains will bring a surge of warm air to the region on 

Saturday along with some small chances for rain across far north-

central Wisconsin. This will likely be the warmest day in the 

next week as temperatures top out in the 50s across central 

Wisconsin with a 30-60% chance of hitting 60 degrees south of 

Highway 10.



The cold side of this low pressure system will track through the

area Saturday night, bringing colder temperatures and a rain/snow

mix as a cold front sinks south through Sunday. Chance of precipitation

is 30-50% with most of the precipitation occurring on Saturday 

night. Probability of >2" of snow for the 24 hr period ending 

Sunday evening is now around 20%, trending up slightly over last 

few NBM runs. 



High pressure will then provide dry weather to the area early 

next week. Temps will start off at or slightly below normal, but 

quickly rebound to slightly above normal by the middle of next 

week. A clipper system will also be moving through the middle of 

next week. This could bring a round of rain/snow later Wednesday 

into Thursday. Higher-end precip with this system would be 0.5 

inch of QPF. Top end snowfall (90th percentile) is around 2-3", 

mainly near the Upper Michigan border. At this point, this clipper

represents the most notable system next week.



&&



.AVIATION...for 18Z TAF Issuance

Issued at 1246 PM CDT Thu Mar 19 2026



Scattered MVFR to VFR clouds for the rest of the day. Better

chance of bkn LIFR-MVFR clouds will be tonight, lowest in central

WI to north-central WI. A clipper will bring some light rain, 

freezing rain and snow tonight, mainly along the Upper Michigan 

border. Nighttime cooling and low-level inversion with ongoing

melting snow sets up potential for fog late tonight into Friday

morning central to north-central WI. 



Winds will be light overall, but low-level wind shear (SW 40-50

kts veering NW to 30 kts) will develop all sites tonight into 

Friday morning.



&&



.HYDROLOGY...

Issued at 201 PM CDT Thu Mar 19 2026



As temperatures warm later into the weekend, the snowmelt will 

result in increasing fast flows and rising river levels. Some 

rivers could reach bankfull or even minor flood stage. The lack 

of a rapid, significant warmup points to a more gradual rise in 

area rivers as opposed to widespread rapid rise flooding. That 

being said, the flooding situation will be monitored closely given

how much water is locked up in the current snowpack across the 

region. Latest Snow Water Equivalent (SWE) here at our office is

now 2.88 inches with a snow depth of 14 inches. This matches the

current NOHRSC snow depth and SWE analysis pretty well. Modeled

snowpack temperature from the NOHRSC site points to ripening of

snowpack (really starting the melting/runoff process) over 

central WI as early as Friday, with more widespread ripening of 

snowpack up over the area on Saturday.



&&



.GRB WATCHES/WARNINGS/ADVISORIES...

None.



&&



$$



DISCUSSION.....JLA

AVIATION.......JLA

HYDROLOGY......JLA