696 
fxus63 kapx 171959 
afdapx 


Area forecast discussion 
National Weather Service Gaylord Michigan 
359 PM EDT Wednesday Mar 17 2010 


Synopsis.../issued at 355 PM/ 


High pressure will continue to dominate the weather over the 
Great Lakes through Thursday...keeping warm and dry conditions on 
tap through this time. Friday may be another warm one. However...a 
developing area of low pressure will be approaching...bringing 
cooler temperatures...a chance for rain and possibly even snow for 
the weekend. There is still a fair amount of uncertainty with this 
storm track and strength of this low...so to what extent the 
precipitation will line up with the intrusion of cold air is a bit 
unclear. 


Berger 


&& 


Short term.../issued at 355 PM/...tonight 


High pressure over the central portions of the country and Great 
Lakes...will generate dry and mild conds over the state tonight. 
Additional subsidence will be from a 500mb ridge...edging into the 
region from the upper Midwest. Model soundings and moisture forecasts 
showing dry conds to linger over the northern lakes tonight...with 
850/500mb relative humidity around 30 percent over much of the County Warning Area into Thursday 
morning. However 850/500mb relative humidity increases to 50pct over eastern upper 
overnight...in response to a weak surface feature dropping south from 
central Canada into Northern Lake Superior overnight. Therefore will 
increase clouds over east upper a tad for the overnight period. 


Overall will continue a dry and mild forecast tonight...as overnight 
lows only drop into the upper 20s and lower 30s as southwest winds 5 
to 10 miles per hour develop in response to the surface boundary currently dropping 
south across Ontario. 


Swr 


&& 


Long term.../issued at 355 PM/...Thursday and beyond 




Main focus on the extended part of the forecast will focus on the 
upcoming weekend...as the weather turns more active. Temperatures 
will turn much colder heading into the weekend...with a mixture of 
snow and rain expected throughout the first half of the 
weekend...then another shot for snow early next week. 


Thursday into Friday...as a middle level wave works eastward across 
central Canada...northern Michigan will remain under the influence 
of weak middle level ridging...providing a continuation of tranquil 
weather conditions through weeks end. Only concern will be the 
encroachment of some high/middle level clouds which may act to keep 
temperatures 5 to 10 degrees cooler on Friday. However...as far as 
Thursday GOES...likely our warmest day of the week with highs easily 
climbing to the 60 degree plateau...with some middle/upper 60s possible 
in downslope flow areas of northeast lower Michigan. 


Friday night...middle level wave across Canada will skirt by the area 
to the north...dragging a baroclinic zone into northern Michigan. 
Meanwhile...southern stream wave will act to develop a surface low 
in the Ohio Valley. A band of fgen precipitation will likely form on 
the northwest side of this system...although quite a bit of 
uncertainty still remains on the exact placement of this band of 
precipitation. As of right now...it appears by late Friday 
night...light precipitation will break out across northern lower 
Michigan...perhaps keeping eastern upper on the drier side. 
Regardless...only change was to increase probability of precipitation for the second half of 
Friday night. At least early on...the precipitation will be 
primarily rain. 


Saturday/Saturday night...light to moderate precipitation will 
continue across northern lower Michigan during the day...eventually 
drifting south and east as the area of low pressure to our southeast 
begins to lift away from the area. As it appears right now...models 
may be over doing the cold air a touch and feelings are that we will 
likely see more rain than snow through much of Saturday. I think we 
may start to change over to snow on the northern edges of the band 
of precipitation as the colder starts filtering in Saturday evening. 
However...snow accumulations at this Point May not be all that 
impressive considering a good chunk of the event may be a mix of 
rain and snow. However...perhaps an inch of accumulation may be 
possible by early Sunday morning. Conditions certainly turning much 
colder as the cold air begins to funnel into northern Michigan. 


Sunday...has actually been trending towards a drier day...as we wait 
for another weak clipper system dropping into the area from the 
northern plains. Have trended probability of precipitation downward...but with a few more 
forecast cycles...these probability of precipitation may be dropped altogether. 
However...with so much uncertainty with the weekend...opting to keep 
some small chances for snow. 


Sunday night Onward...a clipper system will drop across northern 
Michigan late in the weekend...producing a better chance for some 
light to moderate snowfall. At this point...system will be a quick 
hitter...so snowfall amounts will remain on the lighter side 
(although certainly more than we have seen in quite some time). As 
the system departs Monday...we may actually get cold enough air into 
the Great Lakes for a brief period of lake effect snow. However...by 
Monday night into Tuesday...we already start to warm as as upper 
level ridging builds into the Great Lakes. 


Kas 


&& 


Marine.../issued at 355 PM/ 


Winds and waves expected to remain below Small Craft Advisory criteria tonight 
through the forecast period...as high pressure lingers over the 
central parts of the country and Great Lakes region. This pattern 
will generate dry conds into Friday...over the Northern Lake nearshore 
waters. A weak frontal boundary slowly dropping across Ontario 
Thursday...will generate southwesterly winds through the nearshore 
period. 


Swr 


&& 


Aviation.../issued at 117 PM/...valid for 18z tafs 


High pressure over the state and upper Midwest...to remain the 
main feature through the taf period. This pattern will continue to 
generate IFR ceilings/visibilities over northern Michigan taf sites into Thursday 
afternoon. Will include low level wind shear to taf sites after 06z...as middle level 
winds increase above developing diurnal low level inversion. 


Swr 


&& 


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


&& 


$$