Area Forecast Discussion
Issued by NWS Green Bay, WI

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FXUS63 KGRB 161907

Area Forecast Discussion
National Weather Service Green Bay WI
207 PM CDT Sun Jun 16 2019

Forecast discussion for routine afternoon forecast issuance

Issued at 204 PM CDT Sun Jun 16 2019

Seasonably cool weather along with showers at times during the
upcoming work week.

The large scale pattern across North America was blocky at high
latitudes, with a somewhat diffuse band of westerlies to the south
across southern Canada and the CONUS. A broad, shallow trough
extended from the Northern Plains to the St. Lawrence Valley. The
pattern will change little during the first several days of the
forecast period. During the middle to latter part of the upcoming
work week, energy from the Pacific will begin to strengthen the
westerlies across the CONUS and carve out a trough over the
Intermountain West. In response, ridging will increase across the
Mississippi Valley late in the period.

The forecast area is expected to remain on the cool side of the
primary frontal zone stretched out along the southern edge of the
westerlies. That will keep daytime temperatures AOB normal,
through they won`t be as cool as they were this weekend. Weak
disturbances propagating through the westerlies will produce
scattered light precipitation at times. Amounts will be modest for
most of the period, but the potential for more widespread/heavier
amounts will increase late in the period as energy from the
amplifying trough out west begins to reach the area.

.SHORT TERM...Tonight and Monday
Issued at 204 PM CDT Sun Jun 16 2019

Weak shortwave trof and baroclinic zone provided sufficient lift
for persistent light rain across the southeast half of the
forecast area today. Trof moves off/weakens this evening. Low-
level moisture and weak cyclonic flow should keep clouds and
perhaps a shower or drizzle lingering into the early evening in
the southeast.

Surface ridge is expected to expand southward across the area
later tonight into Monday. More sun on Monday in the southeast
part of the forecast area will boost temps closer to normals.
Another low amplitude shortwave trof will move out of northern MN
and bring clouds into the northwest part of the area during the
day with showers by late afternoon or evening.

.LONG TERM...Monday Night Through Sunday
Issued at 204 PM CDT Sun Jun 16 2019

The forecast challenges remain the same as yesterday. While the
overall weather pattern and forecast is pretty clear cut, the
details/specifics remain are difficult to ascertain.

A series of very low amplitude middle and upper level impulses
will cross the area Monday night through Tuesday night. A minimum
in the rain chances will occur Wednesday through Thursday, though
it`s not possible to totally rule out precipitation during that
time frame. Nothing really improves as far as timing of shortwaves
or agreement among the models beyond that point. But the large
scale pattern will be becoming increasingly favorable for
precipitation, so PoPs trended upward late in the week and into
next weekend.

The standard forecast initialization grids based on a broad-based
blend of guidance products looked adequate, so no significant
changes were necessary.

.AVIATION...for 18Z TAF Issuance
Issued at 204 PM CDT Sun Jun 16 2019

A weak upper-level disturbance pushing through the area will lead
to scattered rain showers and some MVFR ceilings through afternoon
across southern airports. Farther north, VFR conditions are
expected to prevail through this TAF issuance. VFR conditions
expected Monday, but more clouds and showers possible in the
northwest airports by mid-late afternoon.



LONG TERM......Skowronski
AVIATION.......JKL is the U.S. government's official web portal to all federal, state and local government web resources and services.