Area Forecast Discussion
Issued by NWS Green Bay, WI

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
000
FXUS63 KGRB 182310
AFDGRB

Area Forecast Discussion
National Weather Service Green Bay WI
610 PM CDT Sat Mar 18 2017

Updated aviation portion for 00Z TAF issuance

.SHORT TERM...Tonight and Sunday
Issued at 219 PM CDT Sat Mar 18 2017

Low clouds lingered across the region this afternoon. Temperatures
ranged the upper 20s across the far north to the lower 40s across
east-central Wisconsin. For the remainder of the afternoon into
this evening, most of the low clouds should dissipate around
sunset or shortly after. Later tonight, mid and high clouds will
move into the area later tonight into Sunday morning.

On Sunday, increasing south winds are expected ahead of a cold
front. Most of the rain should hold off until evening. However,
the gfs model was more aggressive with scattered showers during
the afternoon across the north. Have spread small chances of rain
eastward to account for this scenario. Models do indicate
moderately steep mid level lapse rates around 7.5 c/km, thus could
not rule out an isolated thunderstorm Sunday afternoon. Will let
midnight shift decide to add thunder to the forecast.

.LONG TERM...Sunday Night Through Saturday
Issued at 219 PM CDT Sat Mar 18 2017

Forecast concerns in this period revolve around precip chances
Sunday night into early Monday with better chance late in the
week.

Early in period...A cold front will slide east from MN to eastern
WI Sunday night. Ahead of the front, low level moisture
sufficient for scattered showers. Steep lapse rates may be enough
for isolated thunder, but better chances south.

Skies clear Monday night with strengthening cold advection post
frontal passage.

Mid week...Canadian high pressure will hang around the region
from Tuesday through Wednesday night. Temps on Wednesday AM quite
cold with Canadian high centered over Lake Superior. Minor lake
effect snow showers could impact the snow belt of Vilas County
for parts of this time period, but the airmass will be quite dry,
so not expecting any accumulation.

Later in the week...The next chance of widespread precip will
occur late Thursday through next Saturday with strong shortwave
trof and associated low pressure system. Significant differences
in 18/12Z ECMWF (slower and much farther south) and GFS (faster
and north). Canadian model is closer to the ECMWF. Plenty of time
to work out details. Regardless, gulf moisture should be
plentiful. Some wintry precip expected Thursday night into Friday
morning with initially cold air mass in place, but transition to
rain/mix likely across most of the forecast area.
&&

.AVIATION...for 00Z TAF Issuance
Issued at 604 PM CDT Sat Mar 18 2017

Stratocumulus clouds should gradually erode during the mid to late
evening as high pressure edges into the western Great Lakes. Until
then, expect MVFR conditions to persist over most of north central
and central WI. Increasing high clouds will arrive later tonight
and Sunday morning. South winds will pick up Sunday afternoon,
with gusts to 15 to 20 kts expected.

A strong low-level jet will take aim on north central WI late
tomorrow afternoon, and may cause scattered showers to develop.
Of greater concern will be the potential for LLWS at the RHI TAF
site, mainly after 22z/Sunday.

&&

.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

SHORT TERM.....Eckberg
LONG TERM......JKL
AVIATION.......Kieckbusch


USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.