Weather

155 
fxus63 kapx 280710 
afdapx 


Area forecast discussion 
National Weather Service Gaylord Michigan 
310 am EDT Thursday Aug 28 2008 


Synopsis.../issued at 310 am/ 


High pressure center (both at the surface and aloft) has pushed 
further east of Michigan early this morning...as a cool front 
advances eastward into the western Great Lakes region. Front currently 
extends from The Arrowhead of Minnesota into northwest Iowa and eastern 
Nebraska. Several areas of convection continue to fire along this 
boundary...fueled by a 40 knots 850 mb jet maximum...850 mb Theta-E ridging 
and a well-defined instability axis along and ahead of the front. 
Closer to home...skies remain clear across most of the County Warning Area. Only 
cloud cover to speak of is a scattered/broken line of mainly high clouds 
across eastern Upper Michigan and Lake Michigan well in advance of the 
approaching front. Front will produce a good chance of precipitation for 
Michigan over the next 24 to 36 hours. Dry high pressure will then 
build back into Michigan for this Labor Day weekend...featuring warm 
weather for the late Summer Holiday. 


&& 


Short term.../issued at 310 am/...today 


High clouds will increase from west to east across our County Warning Area this 
morning...but increasing low/middle clouds will hold off until this 
afternoon...at which time the 850 mb Theta-E ridge and instability 
axis begin to enter western sections of our County Warning Area. Instability will be 
very limited this afternoon...with sb cape hard to come by and 
700-500 mb lapse rates holding around 5.5 c/km. Low levels will stay 
rather dry through the afternoon as well. Upper divergence will develop 
across western sections of our County Warning Area this afternoon...and with increasing 
middle level moisture and low level moisture late in the day...will 
maintain a small chance of rain showers/thunderstorms and rain this afternoon for eastern upper and 
northwest lower Michigan. Do not expect severe weather due to insufficient 
instability. NE lower Michigan should stay dry and warm. High temperatures 
this afternoon will peak in the middle 70s to lower 80s. 


&& 


Long term.../issued at 310 am/...tonight through Sunday 


Vigorous short wave ahead of the 500 mb trough will aid in pushing 
the cool front through Michigan tonight. Latest NAM still suggest best 
lift and deepest moisture will sweep through our County Warning Area tonight...and may 
not completely clear eastern sections of lower Michigan until Friday 
morning. See no reason to stray from likely probability of precipitation across our entire 
County Warning Area tonight. Will also leave a small chance of rain showers in the Friday 
morning forecast for our eastern zones. Lack of sufficient instability 
will limit chances of thunder...but good upper level support via the 
strong short wave and descent low level convergence along and ahead 
of the surface front warrants a continued mention of thunder 
tonight. Do not expected severe weather. Low temperatures tonight will drop into 
the low to middle 60s under mainly cloudy skies. 


Large area of surface high pressure and dry air through the column will 
settle into Michigan for Labor Day weekend...providing mainly clear 
skies and a rather light wind regime. A warming trend will begin 
Sunday as low level warm air advection kicks in on the backside of the surface high 
center. Afternoon highs will warm from the upper 70s/lower 80s on 
Friday to the middle to upper 80s by Labor Day. Overnight lows will 
warm from the upper 40s to middle 50s Friday night to the upper 50s to 
middle 60s by Monday night. 


&& 


Marine.../issued at 310 am/ 


Surface pressure gradient will tighten ahead of the cool front... 
increasing winds and waves to Small Craft Advisory criteria this afternoon and early 
evening across Whitefish Bay...the St Mary's River system and the 
nearshore areas along Lake Huron. 


&& 


Aviation.../issued at 134 am/...valid for 06z tafs 


VFR conditions expected through Thursday evening. An approaching 
cold front and associated upper level disturbance will likely 
bring showers and possible embedded thunder to the region 
overnight Thursday. Low end MVFR conditions are possible. 


Ajs 


&& 


Apx watches/warnings/advisories... 
Michigan...none. 
Lm...none. 
LH...none. 
Ls...none. 


&& 


$$