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Area forecast discussion 
National Weather Service Milwaukee/Sullivan WI
156 am CST Thursday Mar 5 2015

Today and tonight... forecast confidence high.

A strong 185 knot 250 mb jet maximum from the middle Mississippi Valley to
the eastern Great Lakes will move off to the east as an upper trough
moves into Wisconsin this morning. This places the left entrance
region of the jet over the area this morning as the weak upper
divergence becomes convergent. 700 mb downward motion becomes
stronger before becoming weak upward as a second weaker trough moves
into southern Wisconsin late tonight.

The 850/700 mb layers remains dry...until moisture begins to
increase toward sunrise Friday west of Madison. Shallow higher 925
mb just enough for the potential of a few afternoon
fair weather cumulus clouds.

Weak 925/850/700 mb warm air advection begins today and increases

Expect sub zero temperatures early this morning but surface winds
will be rather light as the surface high builds into the middle
Mississippi Valley. Wind chills will be mainly in the 10 to 15
below range for a time. Temperatures will drop again early
tonight...then become steady or slowly rising late as southwest
winds develop behind the high dropping into the Ohio River valley.

Light winds in the 1 to 3 thousand feet range become north for a brief
time this morning and may bring lake clouds close to shore...but
should remain out over the lake.

Friday through Sunday...forecast confidence...medium

Kept some flurries in the forecast for Friday as a shortwave
moves through...though model soundings are showing a bit more dry
air in the middle levels than 24 hours ago.

Another weak wave will slide through Saturday...but moisture and
lift are lacking once again. Should see mostly cloudy skies...but
held off on mention of flurries for now.

The Canadian and European model (ecmwf) are showing a more potent wave for
Saturday...with an area of rain/snow sliding across southern
Wisconsin. The GFS has a weak system and is dry. Not a high
confidence went with slight chance probability of precipitation.

Temperatures are expected to warm to around normal values for the

Monday through Wednesday...forecast confidence...medium

The flow will turn more zonal for early next week...allowing for
milder air to move into southern Wisconsin. Could some 40s for the
first time since the middle of January...maybe even 50 Tuesday and
Wednesday...which has not happened since mid-December.

Some uncertainty with how much the snow pack will impact the
milder temperatures. Also...if dewpoints get high enough while there is
still snow on the ground...might have to deal with some fog.

May be cooler near Lake Michigan Wednesday...depending on the
model. The GFS is breezy southwest winds ahead of an approaching
cold front...which would result in milder temperatures across the
forecast area. The European model (ecmwf) has much lighter southerly winds and
allows for onshore winds and cooler temperatures near the lake.


Aviation/12z tafs/...

VFR conditions through the forecast as a large high moves across the
middle Mississippi Valley towards the Ohio River valley. A few clouds
around 25 hundred feet are possible this afternoon.

Light winds in the 1 to 3 thousand feet range become north for a brief
time this morning and may bring lake clouds close to shore...but
should remain out over the lake. Mainly light northwest surface
winds will become west today then southwest tonight.



Northwest winds will become west and continue to ease as a large
high over the middle Mississippi Valley moves into the Ohio River valley


Mkx watches/warnings/advisories...


Today/tonight and aviation/marine...hentz
Friday through Wednesday...ddv

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