FXUS63 KGRB 192302

Area Forecast Discussion
National Weather Service Green Bay WI
602 PM CDT Mon Aug 19 2019

Updated aviation portion for 00Z TAF issuance

.SHORT TERM...Tonight and Tuesday
Issued at 233 PM CDT Mon Aug 19 2019

Sunny skies prevailed across the region this afternoon.
Temperatures were in the 70s to around 80 degrees. For
tonight, the combination of mostly clear skies and light
winds should allow for some patchy fog to develop after
midnight, especially with the longer nights. Low temperatures
will be mainly in the 50s, with our typical cold spots across the
north are expected to drop into the upper 40s.

On Tuesday, a cold front is expected to drop southeast into the
area during the afternoon. Meanwhile, a system passing to the
south could bring some showers and storms to central and east-
central Wisconsin during the afternoon. The main concern for
severe weather on Tuesday afternoon will be across north-central
Wisconsin. Models indicating 0-6 km shear values of 30 to 35 knots
while bufkit soundings at Rhinelander indicated 1,000 to 1,500
J/KG of CAPE and total totals around 50. This would support the
marginal risk of severe storms across portions of central and
north-central Wisconsin Tuesday afternoon. Will mention the risk
of severe weather in the Hazardous Weather Outlook (HWO). Used
some of best performing guidance for highs on Tuesday.

.LONG TERM...Tuesday Night Through Monday
Issued at 233 PM CDT Mon Aug 19 2019

The main forecast concerns are thunderstorm chances and potential
severe weather Tuesday night, a period of cooler temperatures, and
timing the return of precipitation chances late in the weekend.

Due to recent model trends, have slowed down the progression of
pops with the cold frontal passage Tuesday night. The best chance
of storms would appear to be over north central WI during the
evening, with lesser chances as instability wanes overnight. SPC
just added a Marginal risk of severe storms over the northwest
half of the forecast area, where CAPE will be in the 1000-1500
j/kg range and deep layer shear will be 30 to 35 knots during the
early evening.

A couple short-wave troughs will move through Wednesday into
Wednesday night, but it looks like the air mass will be too dry
to support precipitation development.

Canadian high pressure and a building upper level ridge will bring
an extended period of dry weather, which is likely to persist
through Saturday night. Temperatures will be below normal during
this period, with the coolest readings occurring Thursday into
Thursday night, when H8 temperatures drop to +3 to +4 C. Will
likely see low temperatures in the upper 30s and lower 40s in the
typical cold spots late Thursday night.

Short-wave energy will break down the upper ridge toward Sunday,
and return flow will increase on the back side of the departing
Canadian high. This should result in a small chance of showers
and storms west on Sunday, and a better chance regionwide by

.AVIATION...for 00Z TAF Issuance
Issued at 602 PM CDT Mon Aug 19 2019

Good flying weather will continue this evening through
at least noon Tuesday, with clear skies, light winds and excellent
visibility. Scattered showers and thunderstorms and MVFR conditions
are expected Tuesday afternoon and evening with an approaching
cold front.



SHORT TERM.....Eckberg
LONG TERM......Kieckbusch
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