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Area forecast discussion 
National Weather Service Grand Rapids Michigan
1115 PM EDT Sat Sep 20 2014

Latest update...
aviation

Synopsis...
issued at 915 PM EDT Sat Sep 20 2014

A chance for showers and thunderstorm overnight with showers
lingering into Sunday. Clearing is expected to occur Sunday late
in the day with patch frost possible across northern lower
Michigan Sunday night. Pleasant week expected with only occasional
chances for showers/thunderstorms.

&&

Update...
issued at 915 PM EDT Sat Sep 20 2014

Break in precipitation chances through midnight...with the next
shot for showers/thunderstorms coming from the area of showers
currently in Minnesota and Wisconsin. These should arrive in the
middle of the night but severe weather is not anticipated at this
time. Some breezy conditions and lightning along with brief heavy
downpours possible.

&&

Short term...(this evening through Monday night)
issued at 319 PM EDT Sat Sep 20 2014

Forecast concerns deal with severe potential tonight.

Radar trends show storms continuing to develop across the County Warning Area.
Instability has increased a bit with Li/S near -2c. However there is
still quite a bit of convective inhibition in place. That cinh
decreases toward the far southern County Warning Area. If we're going to see severe storms
this afternoon they will be over the far southern County Warning Area. This is also where
the greatest shear is...near 50 kts. Middle level jet moving in will
also aid in storm development. Storm Prediction Center has placed the southern row of
counties in a severe watch into the evening. The severe potential will
last through middle to late evening and wind gusts in the 50-60 miles per hour
range are the main threat.

A wave developing on the frontal boundary in conjunction with a
strong short wave moving across the Great Lakes will result in
showers in the grids tonight and Sunday morning. High pressure
builds south by afternoon setting the stage for good radiational
cooling Sunday night. We have some patchy frost in the grids over
the far NE County Warning Area Sunday night with lows there in the middle 30s.

Long term...(tuesday through saturday)
issued at 319 PM EDT Sat Sep 20 2014

Quiet weather expected in the extended period as the Great Lakes
region is dominated by strong ridging at the surface and aloft. With dry
soundings and general subsidence we should see temperature ranges
greater than guidance...with maxes a bit warmer and mins a bit
cooler. Made some tweaks in that direction.

&&

Aviation...(for the 06z tafs through 06z Sunday night)
issued at 1115 PM EDT Sat Sep 20 2014

Conditions will continue to gradually deteriorate to primarily
MVFR/IFR overnight due to development of low cloud cover and some
patchy fog. Scattered showers will redevelop overnight as well along
with a slight chance for a thunderstorm. Primarily MVFR conditions
are expected Sunday morning and afternoon due to low clouds and
scattered showers. Conditions should gradually improve to VFR Sunday
evening as clearing develops.

&&

Marine...
issued at 347 PM EDT Sat Sep 20 2014

Continued with the Small Craft Advisory through Sunday night. Winds will increase
Sunday but remain just below gales.



&&

Hydrology...
issued at 319 PM EDT Sat Sep 20 2014

River flooding is unlikely given quantitative precipitation forecast over the next 24-48 hours.
However...any locally persistent convection may lead to small stream
and poor drainage issues. Per ncrfc ensemble quantitative precipitation forecast river
scenarios...some of the smaller streams and rivers in south central
lower Michigan may approach bankfull if rainfall amounts achieve the maximum
expected /95 percent confidence interval/ quantitative precipitation forecast threshold.

&&

GRR watches/warnings/advisories...
Michigan...none.
Lm...Small Craft Advisory until 8 am EDT Monday for lmz844>849.

&&

$$

Update...maczko
synopsis...maczko
short term...93
long term...ostuno
aviation...Laurens
hydrology...cas
marine...93

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