659 
fxus63 kmkx 082003 
afdmkx 


Area forecast discussion 
National Weather Service Milwaukee/Sullivan WI 
300 PM CDT Friday Aug 8 2008 


Discussion...forecast emphasis on threat of precipitation later 
tonight in the west and across the entire County Warning Area on Saturday. 


Short term.../tonight through Monday/. 


ND/Minnesota convection associated with surge of middle level warm air 
advection north of weak warm front. NAM 850-700 moisture flux 
convergence currently depicting present convection well...tracks 
southeast through the night into northeast Iowa. Short term guidance 
has been in good agreement the last several runs on keeping 
warm...moist surge just to the west of County Warning Area. Latest Storm Prediction Center sref percent 
of measureable precipitation agrees and keeps higher threat to the 
west until after 12z. Cras forecast also keeps coldest cloud tops to 
the west of the MS river through 12z. Despite light winds...cirrus 
blowoff should preclude fog and keep temperatures slightly above 
this mornings readings. 


GFS and NAM now in reasonable agreement on cool front sweeping 
through southern Wisconsin during Saturday afternoon. Impressive 
cyclonic shear during this time. Thinking dewpoints will likely 
reach the upper 50s to around 60 which would result in sbcapes 
nearing 1000 j. Low wetbulb zeros and enough shear for convection to 
become briefly organized for several hours. Post frontal gusty 
winds for a time near the lake...which will carry into the evening. 
Unseasonably cool temperatures expected away from the lake Sun night 
with a few locations dipping below 50. Otherwise high pressure 
building into the western gtlakes lingers into Monday with low 
humidity and comfortable conditions. 


Long term.../Monday night through next Friday/. 


Confidence remains on the low side for extended period...however 
still see some encouraging signs. GFS remains poor with run to run 
consistency over previous four cycles...however last several runs 
showing some continuity in regards to days 4-5. GFS in better 
agreement with European model (ecmwf) and Canadian in showing more amplified and 
slower long wave trough in western Ontario...just west of gtlakes...with 
upstream short wave vicinity of southern can/US border. Extended guidance 
diverges in later periods from Wednesday night Onward as European model (ecmwf) shows long 
wave trough remaining nearly stationary over eastern gtlakes region 
while GFS moves system off to the northeast and emphasizes northern 
plains closed low. Thinking GFS solution looks unrealistic for this 
time of year and will lean more heavily on European model (ecmwf)...which does bring 
more significant short wave trough in northwest flow across western 
gtlakes toward the end of the week. 


Will continue schc probability of precipitation for Tuesday through Wednesday period as weak short wave 
moves through WI during this period. Will be able to hone in on best 
period as we get closer in time to this event. 


Not alot of stock put into GFS 5day 500hpa means due to problems 
with this guidance last several days. Interesting how 5day means go 
through 360 degree transition from troffing over eastern Continental U.S. And 
northwest flow and ridging over WI at start of period to upstream 
troffing settling over Wisconsin from the plains towards the end of 
next week. In both periods...heights remain below normal for middle 
August. 


&& 


Aviation...expect VFR cumulus field to gradually dissipate with loss of 
heating. An area of cirrus riding up top will cruise through southern WI 
into the evening hours...but all in all quiet conditions expected. Tricky 
time frame comes up Saturday afternoon with thunderstorms and rain potential and gusty 
wind shift to the NE. 


&& 
Mkx watches/warnings/advisories... 
WI...none. 
Lm...none. 


$$ 
Short term/long term....11 
aviation................10