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Area forecast discussion
National Weather Service La Crosse WI
556 am CDT sun Aug 25 2019

Short term...(today through Monday night)
issued at 230 am CDT sun Aug 25 2019

Current water vapor imagery showing a rather impressive shortwave
trough moving northeast through the Central Plains. A few showers
associated with this wave were popping up on radar across IA, moving
northeast toward the area -and drier air. As a result, expecting
these to weaken this morning but then pop up again with daytime
heating/growing instability as the wave moves up into the area while
dampening out. Soundings show shallow convection -probably enough
for a few sprinkles from time to time through the afternoon.
Otherwise, shaping up to be a fairly cloudy day with highs in the
70s.

Isolated to scattered showers continue through tonight as warm air
advection/moisture transport occurs ahead of another trough pushing
out of the northern plains into the area.

Models in good agreement with deepening trough over southern
Canada/northern plains pushing a surface cold front into the area
for Monday into Monday night. Strengthening moisture transport ahead
of the incoming front will fuel showers and scattered thunderstorms
through the day. Will have to watch Monday afternoon/early evening
closely. If we can develop enough instability, we'll have enough bulk
shear (0-3km ~25-30kt) to support a few stronger storms mainly south
of I-94. Otherwise, precipitable water values will be increasing
into the 1.5-1.9 inch range which will likely make these showers and
scattered storms efficient rain-makers. Thinking as of now, area-
wide average rainfall with this system will be in the 1/2 t0 1.25
inch range with perhaps a pocket or two of heavier amounts. Not
thinking there will be much in the way of a flooding threat though
as we have been relatively dry of late. Looks like the bulk of the
showers/storms exits east with the cold frontal passage by midnight
Monday night.

Long term...(tuesday through saturday)
issued at 230 am CDT sun Aug 25 2019

Tight pressure gradient in deep cyclonic flow and good mixing will
make for rather breezy days Tuesday and Wednesday. There is also a
chance of a few showers mainly over northern WI as well Tuesday.
Look for highs in the 70s Tuesday, cooling some into the middle 60s
to mid 70s Wednesday.

Latest GFS/European model (ecmwf) show a weak trough/surface cold front coming
through broad/longwave trough which may produce a few
showers/thunderstorms Thursday night.

The rest of the period looks dry and slightly cooler than normal as
Canadian high pressure settles into the central Continental U.S./Upper
Mississippi River valley.

&&

Aviation...(for the 12z tafs through 12z Monday morning)
issued at 556 am CDT sun Aug 25 2019

VFR conditions are expected the next 24 hours, with intervals of
lower clouds in the 4-6kft range interspersed with some mid and
higher level clouds. Can't rule out a few sprinkles or even a
brief shower at either lse or rst into the evening, with winds
pretty much steady-state from the southeast the next 24 hours,
becoming a bit gusty this afternoon.

Will have to watch a very small potential for lower stratus to
sneak northward toward rst very late tonight (mainly after 4 am),
though at the moment, just how far north any lower clouds reach
remains very low confidence.

&&

Arx watches/warnings/advisories...
WI...none.
Minnesota...none.
Iowa...none.
&&

$$

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