995
FXUS63 KGRB 141050
AFDGRB

Area Forecast Discussion
National Weather Service Green Bay WI
550 AM CDT Tue May 14 2024

Updated aviation portion for 12Z TAF issuance

.KEY MESSAGES...

- Low relative humidity may cause increased fire potential this
  afternoon away from the lake and bay.

- Areas of frost are possible over north central and far
  northeast Wisconsin tonight.

- An unsettled pattern will arrive Thursday morning, bringing
  potential for several rounds of rain and storms through the
  weekend.

&&

.DISCUSSION...
Issued at 333 AM CDT Tue May 14 2024

Short Term...Today...Tonight...and Wednesday

A Hudson Bay high is setting up to provide northern and central
Wisconsin with dry and seasonable weather. The smoke from the
wildfires to our northwest should be less evident than the last
few days. There may still be some elevated smoke, but little or
none close to the ground as low level air is coming in from the
northeast.

Low level cold advection will make for a cooler day than
yesterday, especially near Lake Michigan. Clear skies and light
winds should allow temperatures to fall into the low to middle 30s
across north central and far northeast Wisconsin tonight. The air
is quite dry, so frost formation is uncertain. Wednesday will be
around five degrees warmer than this afternoon, with the coolest
temperatures again near the Lake Michigan shore.

Northeast winds gusting to 20 knots will make for building waves
today, but probably below small craft advisory criteria.

Long Term...Wednesday Night Through Monday

Overall, fairly quiet spring weather is expected to persist
through mid-week before a more unsettled pattern arrives Thursday
morning. A train of shortwaves is expected to bring several
rounds of precip to the forecast area through the end of the week,
although forecast confidence significantly drops off toward the
weekend due to timing and strength issues within the current
ensemble guidance. Otherwise, temperatures begin a gradual incline
through the weekend with some locations across central Wisconsin
possibly seeing the upper 70s on Saturday.

Thursday and Friday precip chances... An upper-level disturbance
will spin up a weak surface low over western Minnesota and the
Dakotas Wednesday evening, bringing downstream precip chances to
the forecast area beginning Thursday morning. As the system
approaches from the west and becomes vertically stacked, best
chances for rain Thursday into Friday will be across central to
north-central Wisconsin. However, QPF is expected to be on the
lighter end (~0.1" to 0.4") given the influence of mid-level dry
air from Hudson Bay high pressure to the north. Some thunder
wouldn`t be out of the question Thursday evening as a corridor of
300 to 400 J/kg of surface-based CAPE makes its way up into
central and east-central Wisconsin.

Rest of the extended... Another round of rain looks to arrive
sometime on Sunday following a brief dry spell Saturday. Models
currently disagree about timing and strength of the driving
shortwave, and thus timing and intensity of accompanying precip.
First impressions suggest that upper-level forcing with this
system will be more robust than with Thursday`s, although how much
QPF we get out of it is still uncertain. The track of the PV
anomaly and attendant surface low will determine how much precip
(if any) makes it down into the CWA on Sunday, with the GFS
currently depicting a much drier solution than the ECMWF.

&&

.AVIATION...for 12Z TAF Issuance
Issued at 550 AM CDT Tue May 14 2024

A surface high over central Canada will keep bring in dry air
from the northeast and produce VFR flight conditions through at
least Wednesday evening. There could be some elevated smoke, but
much less than the last day or two.

&&

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

&&

$$

DISCUSSION.....RDM/Goodin
AVIATION.......RDM