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Area forecast discussion 
National Weather Service Green Bay WI
632 PM CDT Tuesday Mar 31 2015

Updated aviation portion for 00z taf issuance

issued at 247 PM CDT Tuesday Mar 31 2015

Mild the next few days with showers and possibly some
thunderstorms Wednesday night into Thursday. Cooler for late in
the week and the weekend.

Progressive and energetic band of westerlies will continue across
much of the Continental U.S. And southern Canada for the rest of the week and the
start of the weekend. A transition to a more southwest flow
regime...though still with only modest amplitude...increasingly
likely for early next week.

The main weather producer the next few days will be cyclone
migrating through southern Canada. Warmer air returning northward ahead of
the cyclone will result in a few mild days across the area. Cooler
air will shift southward in it/S wake...and likely linger into next week.
Expect modest precipitation to occur with the passage of the cold front
trailing southward from the cyclone. An even more favorable pattern for
precipitation could evolve next week as frontal boundary sets up near the
region. Best estimate is that amnts will end up at or above normal for the

Short term...tonight and Wednesday
issued at 247 PM CDT Tuesday Mar 31 2015

Quiet weather is expected in the short term for the most part.
Northeast Wisconsin in a transition zone between a sprawling high
to the east...and an approaching low pressure system out of the
northern plains. Precipitation chances return Wednesday afternoon
ahead of a cold front with showers and isolated thunder in the

Ridging aloft will keep the area dry tonight. Looked at fog
potential for tonight...but wast very overwhelming. While
surface winds will be light again...winds just above the surface
should keep things mixed and hinder any fog development.
Furthermore...looking at upstream observation from last night in the
Dakotas and Montana where our weather for tonight will be
originating fog was noted. If fog were to develop...the
best chances would in the north and east...which will be furthest
away from the tightening pressure gradient as our next system
approaches out of the northern plains.

Models still have the low pressure system and associated cold
front moving into Minnesota and northwest Minnesota Wednesday afternoon. A low
level jet starts ramping up in the early morning hours of
Wednesday...bringing much warmer temperatures into the area and
clouds to the north. In fact...Wednesday should be the warmest day
of the year so far. Some better upper level dynamics will slide
over the state around 18z Wednesday ahead of the main system.
This combined with the low level jet could pop up a few rain
showers in northern Wisconsin in the afternoon...however looking
to our west there are no showers and very limited cloud cover.
BUFKIT soundings show little moisture for shower activity to took slight chances out for the north in the early
afternoon and focused probability of precipitation on the approaching disturbance. With
this in mind...slowed progression of probability of precipitation east in the afternoon as
best chances wont be until the front arrive Wednesday night.

Long term...Wednesday night through Tuesday
issued at 247 PM CDT Tuesday Mar 31 2015

The main weather maker the next few days will be cyclone crossing
southern Canada. The guidance has not changed much in the handling of
the system since yesterday. Edged probability of precipitation upward as we are getting closer
to the event...with categoricals now most lcns at some point.
Continued mention of thunder despite late night/early morning frontal passage as
middle-level lapse rates are quite steep and fairly strong low level jet will be
transporting moisture into the region.

Several of the models have waffled back around to the idea of
secondary WV along the trailing cold front riding far enough north to
clip the southeast corner of the forecast area with precipitation Friday. Just want to
give this one more run to get sorted out before putting precipitation back
in that went with silent 14/S across east-c WI for now.

Little confidence in the exact details of the pattern in terms of
precipitation lcn/timing in the latter part of the forecast. But it seems
likely that a strong frontal boundary will set-up near the region and
provide the focus for precipitation. At this time of much more
likely that the forecast area will end up sitting north of the front...with
chilly Ely flow and periods of precipitation. Some of that could even be

Aviation...for 00z taf issuance
issued at 632 PM CDT Tuesday Mar 31 2015

VFR conditions are expected to be present through the
taf period. Weak low pressure will exit far northeast Wisconsin
this evening...ending light showers over the Door Peninsula.
Thereafter...will see periods of scattered to broken mid-clouds.
Winds on Wednesday...however...will turn to the southeast and become
strong and gusty during the afternoon. Showers and thunderstorms
will be possible Wednesday night.


Grb watches/warnings/advisories...


short term.....Allen
long term......skowronski

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