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Area forecast discussion 
National Weather Service La Crosse WI
1156 PM CDT Tuesday may 26 2015

Short term...(tonight through wednesday)
issued at 245 PM CDT Tuesday may 26 2015

Upper level shortwave trough/surface low lifting northeast/east across
WI this afternoon...and will continue their slow jaunt toward the
eastern Great Lakes tonight/early Wednesday. Deformation/frontogenetically
fueled region of mainly showers north-west of the surface low will lift
northeast...with the mesoscale models keeping much of the forecast area
north of I-90 on the wet side through at least 06z.

The dry day that Wednesday promised is not looking as clear cut
anymore. The upper level trough axis is slated to rest from
northeast WI into the southern part of the Badger state at
12z...while a weaker piece of energy slides down across northeast
WI...into the base of the trough. The mean trough will slip off to
the east...but the other piece of energy slides down during the
afternoon - bringing some low level warm advection with it. The NAM
and GFS build as much as 2 k j/kg of SBCAPE across western/central
WI Wednesday afternoon...outside of the departing rain/cloud shield.
Enough lift/saturation with the shortwave that some associated
shower/storm chances will be needed for at least the I-94 corridor
tomorrow afternoon. Points west of there should see ample sun...and
some warm...Summer-like temperatures around 80.

Long term...(thursday through tuesday)
issued at 245 PM CDT Tuesday may 26 2015

Models remain in good agreement with progressive zonal flow a loft
ushering in various shortwave troughs/ridges through the early part
of next week.

One trough is slated to move west-east across Canada this
week...with the trough axis/bulk of upper level energy swinging
north of the upper Mississippi River valley Friday night. Its
associated surface low is well ahead of the trough...but it will drag a
cold front southwest across the region...linking up with another
low/trough combo across the Southern Plains. The GFS builds 2000+
j/kg of SBCAPE Friday afternoon ahead of the front...with the bulk of
the wind shear along and Post the front. Both the ec and GFS suggest
a perky line of convection is possible late Friday afternoon/evening.
That said...some morning precipitation also appears probable Friday...and
with cloud cover a question much instability could develop
is very uncertain. It is a time frame to watch there is
some potential for strong-possibly severe storms.

Latest GFS run has now come more in line with the ec thinking for
Sat. Both sag that front south by Sat morning...but the GFS had
remained Adamant with slipping an upper level shortwave across the
region Sat morning...riding west-east north of the surface front. This
would result in a wet morning for most of the forecast area. Now
trends in both models - plus the Gem - are dry. Will paint the
forecast this way.

The weekend is looking dry...but relatively cool with 850 mb temperatures
going from 14 c at 00z Sat to 6 c by 00z sun.


Aviation...(for the 06z tafs through 06z Wednesday night)
issued at 1156 PM CDT Tuesday may 26 2015

A short wave trough will move east across the area during the
overnight. This system will produce an IFR/MVFR deck at the taf
site through 27.14z and then ceilings will quickly rise into the
4 to 6k range. These ceilings will then become scattered between
27.14z and 27.17z. They will then remain that way through the
remainder of the taf period.

Through 27... at krst will drop into the 3 to 5
statue mile range.


Arx watches/warnings/advisories...


Short term...rieck
long term....rieck

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