Scientific Forecaster Discussion
Area forecast discussion
National Weather Service La Crosse WI
647 PM CST Friday Mar 7 2014
issued at 647 PM CST Friday Mar 7 2014
Have updated the forecast for northeast Iowa and southwest
Wisconsin to higher precipitation chances through mid-evening.
Per current radar echoes. Surface precipitation is being reported
in the form of sleet and rain under the echo...and dual pol radar
indicating this mix of precipitation as well.
Frontogenetical band of forcing mainly in the 600-800 mb layer
will continue to impact Fayette-Grant counties mainly through 9pm.
The precipitation may be in waves and should slowly shift south
later in the evening. See graphical Nowcast and Special Weather
Statement for more information.
Short term...(tonight through Saturday night)
issued at 227 PM CST Friday Mar 7 2014
Main concern deals with precipitation chances through tonight...
mainly south of I-90.
Currently...a cold front was making passage through the area. This
front had a history of producing some freezing rain this morning
across portions of southeast Minnesota into central WI. Radar continued to
show some very light returns along the frontal boundary but no
surface reports of precipitation at this time. Otherwise...
temperatures across the area were in the 30s under mostly cloudy
Meanwhile...water vapor imagery was showing a middle-level short wave
trough drifting east through the Central Plains. Radar mosaic across
the Central Plains into the Midwest was showing a fine line of
elevated shower activity along the I-80 corridor of eastern Nebraska into
central Iowa with lift over the frontal boundary. However...none of
this precipitation was hitting any surface observation sites at this
Look for the frontal boundary to continue moving south out of the
area tonight as the middle-level shortwave continues to drift east
across the middle/upper Mississippi River valley region this evening.
This will continue to produce a chance of precipitation mainly south
of the I-90 corridor. BUFKIT sounding/thermodynamic profile still
showing the potential for a wintry mix of rain/snow/sleet going into
this evening...then transitioning to all snow as colder air filters
in. Not looking at much in the way of accumulating precipitation
with just a few hundredths of an inch at most and a trace to a tenth
of an inch of snowfall.
High pressure builds into the area on Saturday for a colder/drier
day. May have to deal with some early morning stratus along/south of
I-90...but this should dissipate with increasing subsidence and
mixing with March sunshine. Plan on highs in the 25-30 degree range
with light northwest winds in the 5 to 10 miles per hour range.
High pressure will drift across the area Saturday night with mostly
clear skies. This will allow temperatures to dip down into the 5 to
10 above zero range.
Long term...(sunday through friday)
issued at 227 PM CST Friday Mar 7 2014
For Sunday through Monday...temperatures will be the main focus.
With the storm track shifting north into Canada and middle-level
heights building over the region...milder air will be drawn in from
the snowless plains. Looking like highs will be pushing into the
upper 30s/lower 40s on Sunday...and well into the 40s on Monday.
For late Monday night through Wednesday...GFS/ec continue to show a
middle-level trough dropping through the region for a chance of rain
and snow. Otherwise...plan on highs on Tuesday in the middle/upper
30s...dropping into the middle 20s to lower 30s on Wednesday.
Milder conditions return for Thursday and Friday as middle-level
ridging takes place once again over the region. Highs on Thursday
are expected to top off in the 35-40 degree range Thursday and in
the 40-45 degree range on Friday.
Aviation...(for the 00z tafs through 00z Saturday evening)
issued at 640 PM CST Friday Mar 7 2014
Current MVFR conditions across the tafs will continue to improve
overnight with colder air advection and northwest flow. Some
drizzle may be around in the evening as well.