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Area forecast discussion 
National Weather Service Green Bay WI
233 PM CST sun Nov 29 2015

Forecast discussion for routine afternoon forecast issuance

issued at 233 PM CST sun Nov 29 2015

Mixed precipitation is expected across the area for the first
half of the work week. The best potential for the bulk of the
precipitation to fall as snow is over north-central
Wisconsin...where several inches of accumulation is possible.

Positive upper height anomaly migrating eastward across Canada will keep
the flow across noam at least somewhat split throughout the forecast
period. Strong southern stream trough currently over the intermountain west
will become progressive as well...resulting in a rather prolonged
period of precipitation as it crosses the region during the early to middle
part of the week. That system looks like the only sig precipitation
producer...and it will probably be weakening by the time it arrives
in the area. But it should still generate sufficient precipitation
to result in near normal amnts for the period. The split flow
regime will keep cold air bottled up way north of the area...resulting
in above normal temperatures for the period.

Short term...tonight and Monday
issued at 233 PM CST sun Nov 29 2015

Clouds and temperatures are the main challenge for
tonight/S forecast. It got quite cold where there is snow on the
ground last night but some of that has melted and clouds will be
increasing as well. So kept lows a couple of degrees above MOS.
Low level moisture eventually increases Monday as winds above the
boundary layer become southeast. Not sure if there will be enough
moisture for light rain across the southwest half of the forecast
area Monday afternoon but there will probably at least some
drizzle. Highs should be a couple degrees above normal and high
enough to prevent any freezing problems in the north.

Long term...Monday night through Sunday
issued at 233 PM CST sun Nov 29 2015

The main long-term forecast challenge is trying to discern precipitation
type with the incoming upper system. Model forecast soundings suggest
all modes of generating non-frozen precipitation will be in play...warm
boundary layer temperatures...a warm layer aloft...and a lack of
deep moisture resulting in no ice-crystals seeding lower clouds.
To add to the uncertainty...soundings also suggest localized
cooling of the temperature profile in bands of stronger lift could
result in liquid precipitation temporarily changing to snow...even in areas
well east of the primary rain/snow line.

Structured forecast with the mainly snow northwest and mainly rain southeast...and a
buffer zone from c-NE WI. That/S similar to what we/ve had going
for a while. Precipitation amnts were shaded downward...which fits with the
older filling system that will be crossing the area. May eventually
need an advisory for north-c WI...but still to much uncertainty and
potential for changes to the forecast to issue that yet.

No sig changes to the extended forecast grids based on a broad-based
blend of guidance products.

Aviation...for 18z taf issuance
issued at 1137 am CST sun Nov 29 2015

Mainly VFR conditions expected through tonight. The
exception will be near the lake and Bay and over the far northeast
part of the state where some clouds between 1500 and 2500 feet
may drift in from the north and east. Skies will be cloudy Monday
with a small chance of drizzle and low clouds moving in from the
south during the afternoon.

Grb watches/warnings/advisories...


short term.....Rdm
long term......skowronski

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