Area Forecast Discussion
Issued by NWS Grand Rapids, MI

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FXUS63 KGRR 260539

Area Forecast Discussion
National Weather Service Grand Rapids MI
139 AM EDT FRI AUG 26 2016


Issued at 328 PM EDT Thu Aug 25 2016

A weak cold front moving across Lower Michigan will result in
scattered storms south of a Lansing to Kalamazoo line late this
afternoon. Otherwise, dry weather is expected through Saturday
morning when another front will move across the state. Not much of a
cool down is expected behind that front either. The air will
continue to be humid well into next week.


.SHORT TERM...(This evening through Saturday night)
Issued at 328 PM EDT Thu Aug 25 2016

Forecast concerns deal with ongoing convection across the southern
cwa late this afternoon and then chances for more storms
Saturday/Saturday night.

Latest mesoanalysis shows instability slowly building across the
southeast cwa ahead of a cold front that extends from near Saginaw
Bay southwest to St Joe. But it`s been slow to build due to extensive
cloud cover. However, the cloud cover is thinning and Li`s have
fallen to -2 over the southern cwa. For the next few hours, a few
storms will likely develop south of a Lansing to Kalamazoo line, but
severe wx is not anticipated.

High pressure will build into the state behind the front and
Friday/Friday night will be dry. After that low pressure moving
northeast toward the western Great Lakes will enhance south flow
over the cwa Saturday and chances for storms will increase Saturday
afternoon and night. A fairly strong low level jet is progd with
this front and shear values around 40 kts suggest the potential for
organization and strong storms. However, much of the short wave
energy is progd over northern lower and the U.P. so that may be a
mitigating factor.

.LONG TERM...(Sunday through Thursday)
Issued at 328 PM EDT Thu Aug 25 2016

A weak shortwave trough is damping out as it tops the upper high
centered over the Mid-Atlantic states on Sunday. Sfc low with
trailing cold front could touch off showers and a few thunderstorms
early Sunday which should end Sunday night as sfc ridging builds in.

The break in precip chances is short lived as an area of warm
advection/isentropic ascent begins Monday and persists through
Wednesday. Upper ridging building in late Wednesday should mean
generally fair weather Wednesday night into Thursday.


.AVIATION...(For the 06Z TAFS through 06Z Friday night)
Issued at 139 AM EDT Fri Aug 26 2016

VFR conditions are expected during the entire forecast period
through 06z Saturday. A few high clouds are floating overhead
tonight, but that should be the extent of cloud cover. Fog
potential is not zero, but is too low to mention at this time with
a drier air mass coming in.

High clouds will remain during the daylight hours on Friday.
Cumulus potential looks low at this time. Winds will come up to
around 10 knots from the W/SW. Cigs will start to lower toward the
end of the forecast period as rain with the next system
approaches. Any significant impacts to aviation interests should
hold off until after 06z Sat.


Issued at 328 PM EDT Thu Aug 25 2016 The weak front that passed
across the lake during the past few hours will not bring strong
winds nor much in the way of cooler air. Thus, we don`t expect a
strong wind/wave response through Saturday. It`s possible that by
Saturday night as south flow increases, we could see waves build
greater than 3 feet.


Issued at 148 PM EDT Thu Aug 25 2016

Showers and a few thunderstorms will bring patchy MVFR and isolated
IFR conditions this afternoon, but VFR should prevail most of the
time. Some light fog overnight could bring MVFR to AZO and JXN but
conditions should be VFR elsewhere. West winds around 10 knots
through evening.


.GRR Watches/Warnings/Advisories...


LONG TERM...Ostuno
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