Area Forecast Discussion
Issued by NWS Grand Rapids, MI

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FXUS63 KGRR 210033

Area Forecast Discussion
National Weather Service Grand Rapids MI
833 PM EDT Thu Oct 20 2016


Issued at 329 PM EDT Thu Oct 20 2016

Areas of rain southeast of Grand Rapids will slowly end overnight.
Then as colder air spreads across the region, scattered lake effect
rain showers will develop along the lake shore late tonight into
Friday night.  Otherwise the remainder of Friday and Saturday will
be dry and cooler with daytime highs only in the low to mid 50s.
Patchy frost will be possible late Friday night east of U.S. 131.

The beginning of next week continues to look mainly dry, with the
next chance of rain holding off until Wednesday and Thursday.  After
highs around 60 on Sunday we will cool to daytime highs in the mid
to upper 40s Monday through Thursday.


Issued at 833 PM EDT Thu Oct 20 2016

Seems the clouds have not shown much sign of clearing this evening
even through models like the HRRR and RAP plus the NAM12 seem to
like the idea. Typically north northeast to north surface winds
with cold advection in the lower levels favors this sort of night
time clearing of the clouds inland of the lake shore. Against that
is that we are well within the upper level cold pool and I have
noted over the years there are many cases where in that situation
the low clouds do not clear. So for now I delayed the low clouds
breaking up over our central CWA till well after midnight. If this
does not happen we will have to increase our forecast overnightlow
temperatures too.


.SHORT TERM...(This evening through Saturday night)
Issued at 329 PM EDT Thu Oct 20 2016

Rain of the southeast counties will continue into this evening, then
gradually dwindle overnight.  Cooler air slipping in will cause some
lake effect showers, mainly Friday afternoon into Friday night.

Low pressure over the Oh/WV borders will only move slowly NE,
causing the rain over the BTL, LAN, JXN areas to continue this
evening.  But as the low continues to pull away this rain will slowly
let up after midnight.

Cooler air will spark lake effect overnight however with a NNE flow
much of this will stay over the lake, perhaps clipping the Points
region.  Into Friday the flow becomes more NNW and inversion heights
will come up as a short wave approaches.  Feel the best timeframe
for showers over SW MI lake shore will come Friday afternoon and
evening.  Then inversion heights come back down once the short wave
is through by late Friday night.

Cloud cover should gradually erode into Saturday, or may even take
until Saturday night as a surface ridge moves in.

The short waves and NW upper flow that follows will keep us cool
with highs only in the low and mid 50s Fri and Sat.

.LONG TERM...(Sunday through Thursday)
Issued at 329 PM EDT Thu Oct 20 2016

The long term begins rather nice with temperatures that will
moderate back into the 60s on Sunday. Although some guidance
suggests that we could reach the mid to upper 60s, there are a
couple of limiting factors. As the upper ridge becomes more
pronounced over the plains, the result is west to northwest flow
with a shortwave quickly dropping through the Great Lakes Region
Sunday afternoon. Much of the precipitation will remain over
Northern Lower Michigan, but afternoon clouds could play a role in
keeping temperatures in the upper 50s north of Grand Rapids. Most
location along and south of I-96 are likely to see more sunshine to
round out the weekend.

Once the shortwave moves through, upper level ridging to the west
keeps Lower Michigan in northwest flow with cooler temperatures to
start next week. Surface high pressure builds in from the plains
resulting in quiet and dry conditions Monday through much of the day

The pattern may become a bit more active by the middle of next week
with a few showers possible along a warm front late Tuesday
afternoon. As of now, higher chances remain west over Wisconsin.
Another system may become better organized over the plains with the
core of the upper jet pushing eastward. The upper trough deepens
over the Great Lakes Wednesday into Thursday with rain becoming
likely late Wednesday into Thursday.


.AVIATION...(For the 00Z TAFS through 00Z Friday evening)
Issued at 725 PM EDT Thu Oct 20 2016

VFR cigs will prevail at MKG through the next 24 hours, GRR will
become VFR with cigs by 03z and then maintain that through Friday
night. AZO and BTL are on the west edge of the light rain showers
from the system and have low MVFR cigs, by 06z cigs should become
none alternate MVFR and then VFR by 12z. JXN will take the longest
to become VFR but even there cigs should become VFR by mid morning
Friday. Most of the rain has ended over the area but a few light
showers are still possible till midnight. They should not be
enough to lower the visibility.


Issued at 329 PM EDT Thu Oct 20 2016

Will maintain the lake headlines as cold advection and brisk north
to northwest flow continues.


Issued at 330 PM EDT Thu Oct 20 2016

Rivers continue to improve through much of the area. Rainfall has
played out today mostly as expected. Small rises may occur along
small streams in affected locations. Otherwise, overall
precipitation chances are rather limited through the next 5 days.
Better chances for rain exist through the middle of next week. River
levels are expected to continue to fall. No flooding is forecast.


LM...Small Craft Advisory until 8 PM EDT Friday for LMZ844>849.



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