944 
fxus63 kapx 191751 
afdapx 


Area forecast discussion 
National Weather Service Gaylord Michigan 
151 PM EDT Friday Mar 19 2010 


Synopsis.../issued at 430 am/ 


A weak storm system moving over Ontario today...will exit into Quebec 
Saturday morning. This system will generate some light rain showers 
or sprinkles...over northern Michigan into this evening. Some mixed 
precipitation...will affect central Michigan and the Saginaw Bay 
region...tonight and Saturday morning. 


However dry and seasonal temperatures will be evident over the 
northern Great Lakes this weekend...as an area of high pressure 
moves across the upper Midwest. 


Dry and unseasonably mild temperatures are expected over northern 
Michigan during the upcoming work week...as high pressure dominates 
the region. 


&& 


Short term.../issued at 1129 am/...today 


Morning surface analysis revealing low pressure system skirting across 
southern Ontario...trailing cold front stretching down across a sliver of 
northwest lower Michigan and continuing on into southern Wisconsin. Robust temperature 
gradient across the front with temperatures dropping sharply into the lower 
30s/20s in northwest Wisconsin...and on down into the teens in Ontario. 
As far as precipitation is concerned...one round of light shower activity 
managed to get going across Northern Lake Michigan into eastern Upper 
Michigan earlier in the morning...spurred on by f-general forcing along 
the front and perhaps a lake induced low level speed maximum atop the 
stable marine layer. Looked like that was going to do it as far as 
measurable precipitation was concerned. However...another round of light 
precipitation is now developing over that same area...and will be impacting 
the tip of the mitt counties/straits/portions of eastern Upper 
Michigan through early afternoon. Will tweak forecasts accordingly. 


Temperatures...eastern Upper Michigan already into gusty northwest flow and 
probably not going much farther with temperatures. Northern lower Michigan a bit 
trickier with the front slicing through the region and varying 
degrees of cloud cover. Overall...have nudged forecast maximum temperatures 
down just a degree or so given the front is already slipping through 
the region. But warmest temperatures will obviously occur over the S/east 
counties...reaching the middle to upper 50s before the colder air 
arrives. 


Adam 


&& 


Long term.../issued at 430 am/...tonight and beyond 


Tonight...surface front continues to press south of the North Woods 
with colder and colder air filling in behind it. Still have upper 
jet...northern stream and initial southern stream initial shortwave energy 
pressing in over the frontal zone. This actually allows a 
secondary fgen band to develop...seen primarily between h7-h5. This 
fgen will flirt with the M-55 corridor by possibly producing some 
early evening light rain/sprinkles...which would quickly turn to 
potential light snow or flurries by late evening (h8 temperatures 
cooling to -6c to -9c...and loss of diurnal surface based warm layer). 
Either way...no significant precipitation is expected...as the 
trend continues to push all forcing/deep moisture further southeast. Am 
expecting fairly cloudy skies from roughly Frankfort to 
Harrisville through the night...as middle and upper level moisture 
will be hard to get away from. Elsewhere...have opted to maintain 
the mostly cloudy sky...with continued Overlake instability and a 
little 10-15kt flow over the lakes. Cloud to keep temperatures up...will 
have upper 20s to lower 30s south...tailing back into the lower 
20s north where there could be some holes in the clouds to help 
cool off a bit more. 


Saturday through Sunday...surface high pressure settling in overhead 
and getting The Squeeze play...as cut off southern stream system 
drifts across the southern Mississippi Valley...and additional northern 
stream energy sweeps across Ontario. Enough subsidence and drying 
with moderating low level temperatures across our neck of the 
Woods for developing sunnier skies. The only spot to stay somewhat 
cloudier..will be near the Saginaw Bay...where pesky higher level 
cloud will still be lingering. All-in-all...quite a nice weekend 
with temperatures in the middle and upper 30s Saturday warming to the lower 
half of the 40s Sunday. 


Later periods...high pressure and dry air dominate the forecast 
through Tuesday with middle level height rises and temperatures 
rising further into the 40s and even some 50s. Added clouds and 
maybe a small chance of light rain arrive Wednesday with a weak 
low pressure system. However...another mild day expected..and the 
way precipitation chances have been for US these last 3 months...am more 
prone to lean towards a "no chance" on that chance of light rain. 


Smd 


&& 


Marine.../issued at 430 am/ 


Cold front passing through the nearshore waters today will bring 
clouds and maybe a sprinkle or two. Main marine issue will be with 
increased northwest winds behind this front with growing Overlake 
instability resulting in Small Craft Advisory for several 
nearshore zones. These winds will flirt with 25-30kts through much 
of the night...before tapering off Saturday and Sunday with 
developing high pressure...and increasing sunshine. Smd 


&& 


Aviation.../issued at 151 PM/...valid for 18z tafs 


Cold front will slip through northern lower Michigan this afternoon 
ushering in much colder air into the state. As this occurs...scattered 
sprinkles are possible through this evening...perhaps a little 
light rain at pln this afternoon. Otherwise...VFR conditions this 
afternoon will give way to lowering ceilings and MVFR conditions 
tonight...as the colder undercuts into the region. 


MVFR conditions to start the day Saturday. But daytime heating and 
drier air overspreading the region should leading to thinning 
clouds by the afternoon. 


Adam 


&& 


Apx watches/warnings/advisories... 
Michigan...none. 
Lm...Small Craft Advisory from 5 PM this afternoon to 5 am EDT 
Saturday for lmz323-342-344>346. 
LH...Small Craft Advisory from 5 PM this afternoon to 5 am EDT 
Saturday for lhz347-348. 
Ls...Small Craft Advisory until 5 am EDT Saturday for lsz321-322. 


&& 


$$ 

National Weather Service Glossary of Abbreviations

Non-Expanded Version (with abbreviations)