Area Forecast Discussion
Issued by NWS La Crosse, WI

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870
FXUS63 KARX 301130
AFDARX

Area Forecast Discussion
National Weather Service La Crosse WI
630 AM CDT MON MAY 30 2016

.SHORT TERM...(Today and tonight)
Issued at 359 AM CDT Mon May 30 2016

At 3 AM, a 1016 mb high pressure area was located across the
Upper Mississippi River Valley. Meanwhile further to the west a
mesoscale convective complex was located over southeast South
Dakota, northwest Iowa, and southwest Minnesota. The 30.00Z models
are in good agreement that the 850 mb moisture transport will
remain across that area through this morning; thus, not
anticipating that this system will affect either northeast Iowa
or southeast Minnesota this morning.

For this afternoon, the 850 mb moisture transport will gradually
increase west of the Upper Mississippi River Valley. In addition,
the 0-1 km mean layer CAPES will increase into the 500 to
1000 J/kg range. This will result in the potential for scattered
showers and thunderstorms. With the both the 0-3 km and 0-6 km
shear generally less than 25 knots, not anticipating any of these
storms will become severe.

For tonight, weak to moderate 850 mb moisture transport develops
across the Upper Mississippi River Valley. This is in response to
the short wave trough moving slowly out of the Northern and
Central Plains. This will promote the development of showers and
storms across the region. As the night continues, there are some
hints in the meso models that moisture transport will weaken
across southwest Wisconsin and parts of northeast Iowa. This could
result in a dry period during the overnight. This is not currently
in the forecast grids, but it is definitely something that should
be watched today. With the 0-1 km mixed layer CAPES less than
1000 J/kg and weak shear, not anticipating any of these storms to
become severe.

.LONG TERM...(Tuesday through Sunday)
Issued at 359 AM CDT Mon May 30 2016

From Tuesday into Wednesday, a short wave trough and surface cold
front will move slowly east across the area. This front is a bit
slower at moving east than in previous runs. This is a result of
some ridging ahead of Tropical Depression Bonnie and on the back
side of a trough located east of New England. The best 850 mb
moisture transport is located across the Upper Mississippi Valley
for Tuesday and then shifts east of the area on Tuesday night and
Wednesday. This should take the heaviest rain to our east. However
with this said, will have to watch for training across urban
areas. The best instability will be found across the area on
Tuesday afternoon and evening. During this time period, the 0-1 km
mixed layer CAPES will climb into the 1000 to 1500 J/kg range.
While the deep layer shear remains weak, the 0-3 km shear does
climb into the 25 to 30 knot range. This along with cold front
moving through the region will support linear development. This
could result in the potential for isolated wind damage. While the
CAPE profile in the soundings remains skinny, could not rule out a
few storms potentially producing up to quarter size hail. This
would fit in well with the Storm Prediction Center`s Day 2
marginal risk.

The next chance of showers and thunderstorms will be from Friday
afternoon into the weekend as a northern stream short wave moves
southeast through the region and then develops a closed low over
the Great Lakes. There is plenty of uncertainty on how far west
the precipitation will extend. If the ECMWF is correct, the area
could be dry for much of the weekend. Meanwhile the GFS has with
low further west; thus, the periodic rain chances would continue.

&&

.AVIATION...(For the 12Z TAFS through 12Z Tuesday morning)
Issued at 630 AM CDT Mon May 30 2016

High pressure continues to drift across the TAF sites, with river
valley fog encompassing KLSE where visibility will dip to 1/4SM at
times through 14Z before quickly improving. Otherwise, look for
some thicker cirrus this morning and mid clouds this afternoon and
tonight. There is a risk for a few showers and storms to clip KRST
this evening and tonight, with a lesser threat at KLSE, with
questions about timing precluding any specific thunder mention at
this time. Winds will remain under 10 knots through the forecast
period, primarily from the south to southeast.

&&

.ARX Watches/Warnings/Advisories...
WI...None.
MN...None.
IA...None.
&&

$$

SHORT TERM...BOYNE
LONG TERM...BOYNE
AVIATION...Lawrence



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