Area Forecast Discussion
Issued by NWS La Crosse, WI

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000
FXUS63 KARX 021138
AFDARX

Area Forecast Discussion
National Weather Service La Crosse WI
538 AM CST Tue Mar 2 2021

.SHORT TERM...(Today and tonight)
Issued at 310 AM CST Tue Mar 2 2021

Forecast concerns in the short term will be brisk southwest winds,
cloudcover and temperatures.

Water vapor satellite imagery from early this morning shows lots of
mid and high clouds over southern Canada into the Northern Plains
and Upper Mississippi Valley. A ridge of 500mb was noted over the
Rockies into the Northern Plains with a closed low off the West
Coast, a small closed low over Oklahoma and northern Texas, and
another closed low over the northeast U.S. 200 meter 12hr height
rises were found over the Great Lakes region with 200 meter height
falls approaching the West Coast. The 00Z MPX sounding was very
dry at 850mb with some moisture noted around 700mb.

Today and tonight, we`ll see the mid-tropospheric ridge flatten
as a shortwave trough tracks across parts of Canada and the U.P.
of Michigan. Surface high pressure will give way to strengthening
southwest flow and 850mb temperatures of -6 deg C. to 6 above C
this afternoon. The HRRR/RAP have max wind gusts developing in the
30 to 40kt range this morning through early afternoon as a
40-60kt low level jet over MN rotates through. The max winds may
be a little high, but did boost wind gusts into the 30 to 35kt
range.  After a cold start, should see temperatures rising this
morning with highs mostly in the 40s this afternoon. The
precipitation will be well to the north of the area today, however
with the warm air advection look for increased mid and high level
cloudiness. The RAP is hinting at some stratus developing across
the eastern part of the forecast area, thus will need to monitor
this. A secondary, weaker shortwave trough will track in the
northwest flow aloft across Minnesota tonight and this should
produce some increased cloudcover east of the Mississippi.
Temperatures will still be above normal tonight with lows in the
20s.

.LONG TERM...(Wednesday through Monday)
Issued at 310 AM CST Tue Mar 2 2021

The extended is looking mainly dry with steadily increasing above
normal temperatures.

The weak shortwave passage will bring a wind shift with some
clouds and backdoor cooling for Wednesday as surface high pressure
builds in. Temperatures should generally be close to Tuesday with
highs in the 30s and 40s. The NAM/NAMnest hint at some low level
moisture and possible light precip. These are outliers, however
since there is a shortwave trough passage will need to continue to
assess as we get closer.

For Thursday, a storm system tracks into the Plains, however the
local forecast area remains far enough to the east to be under the
influence of northwest flow aloft and flow from the east. The EC
EPS has above normal temperatures in the 40s Thursday through
Saturday. The storm system passes to the south and the mid-
tropospheric ridge builds in for Sunday with highs in the 50s.

We could see rain chance return early next week, however the is
still not the best agreement on this. There is good agreement
that temperatures will remain above normal with highs in the 50s.
The NAEFs anomalies increase to 1 to 1.5 standard deviations by
early next week, so not looking at record warmth.

&&

.AVIATION...(For the 12Z TAFS through 12Z Wednesday morning)
Issued at 532 AM CST Tue Mar 2 2021

Low level wind shear will be seen at the TAF sites through 02.14z
at KRST and 02.15z at KLSE.

The 02.06z models are suggesting some 925 moisture will move into
the eastern portions of the area this afternoon and continuing
through tonight. Confidence was not high enough to bring it into
the La Crosse area, so kept VFR ceilings there.

&&

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

$$

SHORT TERM...Zapotocny
LONG TERM...Zapotocny
AVIATION...Boyne


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