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000
FXUS63 KGRB 100253
AFDGRB

Area Forecast Discussion
National Weather Service Green Bay WI
953 PM CDT Tue Apr 9 2024

Updated aviation portion for 06Z TAF issuance

.KEY MESSAGES...

- Confidence continues to increase that a strong low pressure
  system moving across the Great Lakes will bring rain and strong
  winds Thursday into Friday morning. Precipitation totals have
  increased on this forecast package.

- There is a chance of thunderstorms Saturday night. Any storm that
  does develop is not expected to be severe at this time.

- Above normal temperatures will continue into next weekend. Highs
  could reach 70 in spots Wednesday and Sunday inland from Lake
  Michigan.

&&

.DISCUSSION...
Issued at 256 PM CDT Tue Apr 9 2024

Short Term...Tonight and Wednesday

An upper level jet combined with a weak mid level shortwave and
steep low level lapse rates may cause some light rain showers or
sprinkles to central and north-central Wisconsin through early
this evening. Otherwise, skies will clear this evening into the
overnight hours as drier air advects into the region along with
the loss of daytime heating. Despite the clearing skies, low level
warm air advection on southwesterly winds will keep temperatures
fairly warm tonight. Lows tonight are expected to range from the
middle 30s across the north, to around 40 across east-central
Wisconsin and the lakeshore.

Mostly sunny skies and warm conditions are expected for the bulk
of Wednesday as southwesterly winds increase throughout the day.
Clouds will increase during the afternoon along with the chance
for light showers or sprinkles across north-central Wisconsin as
another upper level jet streak tracks through the western Great
Lakes region. High temperatures on Wednesday are expected to
range from the middle 60s across the north, with temperatures
close to 70 across the Fox Valley.

Long Term...Wednesday Night Through Tuesday

The main focus will be on the increasing confidence of a strong
spring storm Thursday into Friday, and then chances of thunderstorms
Saturday night as a warm front lifts northward.

Except for the NAM, the models are in good agreement for a strong
spring storm to move from the Ohio Valley northeast into lower
Michigan on Thursday. The low is expected to deepen to 983mb
on the as it moves into Michigan, resulting in strong northerly
winds on the back side of the system. Rainfall totals have
increased on the forecast package. 925mb/850mb winds would support
the potential for wind gusts over 40 mph. At this point, added
difficult travel to the Hazardous Weather Outlook for now. If the
model runs continue to show these strong wind trends, may need
to add sporadic tree damage and power outages. The last soil
moisture map indicated the top soil was saturated from the
previous few storm, which support the possibility of trees being
uprooted.

There may be a little snow across the far north Thursday night
into Friday morning. Little or no accumulation is expected. The
gusty northerly winds will continue into Friday afternoon before
gradually subsiding late in the afternoon into the evening. Gusts
over 40 mph are still possible in the morning. High pressure will
build into the region Friday night with tranquil conditions on
Saturday. For Saturday night, a warm front will lift northward.
The models are depicting some convective activity breaking out
as the low level jet cranks up. The GFS bufkit sounding indicated
fairly steep mid level lapse rates of 6.5 to 7.5 C/KM and most
unstable capes of J/KG. The main question is where the thunderstorms
develop. A few models have it north of the area. Have a chance of
showers and thunderstorms for this period with the highest chances
near the Michigan border.

It will be a mild day on Sunday with highs in the middle 60s to
lower 70s. Tranquil conditions are expected on Monday with the
next system bring another round of rain Tuesday. High temperatures
for much of the period will run above normal.

&&

.AVIATION...for 06Z TAF Issuance
Issued at 953 PM CDT Tue Apr 9 2024

VFR conditions should prevail through the TAF period. CIGS
between six and ten thousand feet late this evening will
dissipate overnight into early Wednesday morning. CIGS between
five and seven thousand feet will redevelop late Wednesday
morning as an upper level jet tracks through the western Great
Lakes region. Light southerly winds overnight will become
southwest on Wednesday, then become southerly Wednesday evening.

&&

.GRB WATCHES/WARNINGS/ADVISORIES...
None.

&&

$$

DISCUSSION.....Kurimski/Eckberg
AVIATION.......Kurimski