Area Forecast Discussion
Issued by NWS La Crosse, WI

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FXUS63 KARX 172336
AFDARX

Area Forecast Discussion
National Weather Service La Crosse WI
636 PM CDT Thu May 17 2018

.SHORT TERM...(This Evening through Saturday)
Issued at 143 PM CDT Thu May 17 2018

Hard to beat this weather in late May! Really not a whole lot to
talk about over the next few days (just like the past few days),
with low level ridging centered over southeast Canada but branching
westward into the local area as we remain sandwiched between a slow-
moving upper wave over the mid Mississippi River Valley and a series
of shortwaves working onto the Plains ahead of western CONUS broad
upper troughing. Backdoor frontal boundary that worked west earlier
this morning is providing the focus for some cumulus development but
little more, courtesy of renewed mixing of boundary layer moisture
once again delivering little in the way of surface-based
instability. This is a far cry from the NAM/GFS depiction of dew
points soaring into the 60s - looks like those models think there is
way more evapotranspiration occurring that reality (something to
watch closely the next few weeks in model progs).

Tonight should be quiet and comfortable with slightly cooler lows
than last night, with persistence of stronger southeasterly flow into
Friday supporting slightly cooler highs than seen today. Recycling
northward of a lower PWAT minimum hints that despite cooler
temps, we will likely realize lower dew points once again via
mixing. Just a small fire weather concern, especially with
stronger gradient winds, though green-up the past few weeks has
greatly minimized the risk for large fires. Will need to also
watch the potential for some lower stratus to sneak in from the
southeast come Saturday, especially southeast half of the area
with a shortwave passing just to our east, but confidence right
now isn`t the highest. Bigger story is the increasing likelihood
that the majority of showers will hold off through the day on
Saturday with a wedge of drier air intact locally and a lead
shortwave to our west shearing out. It`s doubtful we`ll hear many
complaints if we manage to sneak out a dry start to the weekend.

.LONG TERM...(Saturday Night through Thursday)
Issued at 143 PM CDT Thu May 17 2018

A remarkably stable pattern across the Northern Hemisphere over the
next 10-16 days continues to be advertised among operational and
ensemble guidance, with pretty much a continuation of the same
weather regime across the region. A brief interlude of change will
come Saturday night through maybe Monday as a series of weak
shortwaves meander through the region, delivering a few chances for
mainly just showers as overall instability continues to be lacking.
Can`t rule out some rumbles well south of I-90 but nothing severe
with weak elevated instability and shear lacking.

After that, the phrase "we now return you to our regularly scheduled
programming" comes to mind with broad low level ridging working from
the Great Lakes into the northeast CONUS but maintaining a presence
farther west into our area. Simply put, that should spell more great
late May weather with dry conditions, warm temperatures, and likely
continued lower humidity levels with the Gulf of Mexico "officially"
closed for business into at least mid week.

&&

.AVIATION...(For the 00Z TAFS through 00Z Friday evening)
Issued at 637 PM CDT Thu May 17 2018

VFR conditions will continue through the time period. A scattered
to broken deck of high clouds will be seen across the area through
tonight and it will be mainly clear on Friday. With diurnal
heating, the east southeast winds will gust up to 20 knots at KRST
on Friday afternoon.

&&

.ARX WATCHES/WARNINGS/ADVISORIES...
WI...None.
MN...None.
IA...None.
&&

$$

SHORT TERM...Lawrence
LONG TERM...Lawrence
AVIATION...Boyne



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