Area forecast discussion 
National Weather Service Gaylord Michigan 
732 PM EDT Wednesday Jun 19 2013 


Synopsis... 
issued at 346 PM EDT Wednesday Jun 19 2013 


High pressure will remain over the Great Lakes through tonight... 
providing mainly clear skies and seasonal temperatures. This 
system will slip off to the southeast by Thursday allowing a front 
to sag into and then stall across northern Michigan heading into 
the weekend. This will result in periodic chances of showers and 
thunderstorms beginning Thursday and persisting through the 
weekend. 


&& 


Update... 
issued at 732 PM EDT Wednesday Jun 19 2013 


A scattered-broken line of flat cumulus lingers along a lake breeze collision 
front extending from Manton to north of Hillman. Cloud forecast 
has been updated for the latest trend...otherwise no changes 
needed on this quiet evening. 


&& 


Short term...(this evening through thursday) 
issued at 346 PM EDT Wednesday Jun 19 2013 


Latest surface analysis shows large 1022mb high centered over 
Eastern Lake Huron...helping to keep conditions beautiful over 
northern Michigan with just few passing cirrus and diurnally 
driven cumulus clouds. Further to the west...more cumulus activity was 
seen back over Illinois...Wisconsin and points 
westward...associated with southeasterly return flow bringing a 
moisture return there. The closest weather maker to US is 
associated with a shortwave way to our north moving out of northern 
Manitoba into northern Ontario and the James Bay. An associated low 
pressure system and trailing cold front was seen with this 
feature...helping to touch off some rain showers in Ontario with 
even a couple of lightning strikes seen over SW Ontario late this 
afternoon. 


Tonight...not too much to worry about for tonight...with dry air 
remaining in place and another mainly clear night across most of 
the County Warning Area. Not looking as cold as last night...as the return flow on 
the backside of the high will just be getting underway. Very 
light southerly winds will keep temperatures up a bit...with perhaps a 
slight uptick in dew points. The low lying areas over interior 
portions could still see lows dip into the lower 40s. Would not be 
surprised to even see a rogue sub 40 degree reading over places 
such as gov and the other normal cold spots. The trailing cold 
front will be moving through the u.P. Overnight...bringing some 
scattered showers and perhaps a few thunderstorms to western and 
central sections of the u.P. Clouds will be on the increase for 
eastern upper...with perhaps some showers moving in to northern 
Chippewa County after 09z tonight. Instability is lacking over the 
eastern u... the weakening frontal forcing will keep thunder 
out of the forecast for there. 


Thursday...the remnants of the front stall out over the eastern 
u.P. For Thursday. By this time...am hard pressed to find any decent 
convergence along the frontal zone...and with the better synoptic 
qg forcing well to the north of the County Warning Area...will maintain low chance 
probability of precipitation with mostly cloudy skies for eastern upper for the day. For 
northern lower Michigan...high pressure should remain in control...with 
a southerly return flow helping to boost temperatures up several 
notches from today...along with a bit of an increase in humidity. 
In terms of sensible weather it will bring a bit more cumulus during 
the afternoon...and maybe some middle/high level clouds with the 
frontal boundary...helping to filter the sunshine from time to time 
toward The Straits. Highs look to be well into the 70s to around 
80...cooler over the u.P. Due to cloud cover. While this boundary 
in the u.P. Remains quite weak tomorrow...it may become 
reinvigorated late this week as strong southerly flow ahead of 
developing low pressure moves into the Great Lakes...serving as a 
focus for thunderstorm chances late this week. More on that in the 
long term section. 


Long term...(thursday night through wednesday) 
issued at 346 PM EDT Wednesday Jun 19 2013 


Summer time pattern shaping up over the next several days with 
rising heights aloft/warming 850 mb temperatures. The combination of 
upper level disturbances topping the building upper level ridge and 
a stalled out surface boundary in the vicinity will lead to numerous 
chances for showers and thunderstorms. Forecast high temperatures 
will be challenging due to uncertainty over timing/location of 
possible convective complexes. One thing that you can take to the 
bank...it will turn much more humid. The main forecast concerns 
revolve around probability of precipitation and high temperatures through the entire long 
term. 


Thursday night...high pressure continues to move off to our east 
allowing for a more moist southerly surface flow with 700 mb Theta-E 
ridge encroaching from the west. It looks like a boundary lies out 
across eastern upper so there will be a chance for showers and even 
thunderstorms as instability increases up that way. Not nearly as 
cool with lows in the middle and upper 50s. 


Friday...Theta-E ridge settles across the forecast area. 
Meanwhile...a core of strong winds aloft moves by the north with 
0-6km bulk shear approaching 50 knots across eastern upper and 40 
knots across northern lower. So with a surface boundary draped 
across northern sections of the region in combination with daytime 
heating...could see some thunderstorm development (possibly on he 
strong side). Tough temperature forecast with the amount of cloud 
cover and possible convection in question. Continued to play it on 
the conservative side in this regard with highs ranging from the 
middle 70s to lower 80s. 


Friday night through next Wednesday...status quo with upper level 
ridging and the stalled out front across the region...leading to 
numerous chances for rounds of showers and thunderstorms. Wish could 
be more detailed but models vary on individual smaller scale 
features so will continue to keep the forecast general and go with 
chance probability of precipitation through the period. Have inched temperates up a little 
each day...reaching the middle 70s north to middle 80s central and 
south by Monday...perhaps even the upper 80s southeast. There is the 
potential to top 90 degrees as 850 mb temperatures near 20c...but 
like was said earlier...there is too much uncertainty to know mixing 
depth. Perhaps a bit of relief from the heat and humidity on 
Wednesday as a weak front looks like it will move through from the 
northwest. Lows at night mainly in the uncomfortable 60s to near 
70. 


&& 


Aviation...(for the 00z tafs through 00z Thursday evening) 
issued at 732 PM EDT Wednesday Jun 19 2013 


VFR. High pressure over the eastern lakes will continue to extend 
ridging back into northern Michigan...even as the center of the high 
moves further east. That will keep the northern lower Michigan airmass 
dry. Light winds tonight...just a touch of southerly breeze 
Thursday that will give way to lake breezes. 


&& 


Marine... 
issued at 346 PM EDT Wednesday Jun 19 2013 


Light winds associated with high pressure will result in calm 
conditions over the lakes through Thursday into the weekend. No 
small craft advisories are expected with stable conditions 
remaining. Increasing heat and humidity late this week...combined 
with a stationary frontal boundary will bring a return to 
thunderstorm chances Thursday night into Friday. 




&& 


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


&& 


$$ 


Update...jz 
synopsis...ba 
short term...Nova Scotia 
long term...as 
aviation...jz 
marine...Nova Scotia