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000 
FXUS63 KGRR 230426
AFDGRR

Area Forecast Discussion
National Weather Service Grand Rapids MI
1226 AM EDT Wed Oct 23 2019

LATEST UPDATE...
Aviation

.SYNOPSIS...
Issued at 328 PM EDT Tue Oct 22 2019

-High wave action with beach and bluff erosion continues into
 early Wednesday

-Gusty winds may cause scattered power outages along lakeshore

-Light rain possible late Wednesday into early Thursday

-Saturday night into Sunday morning is looking wetter

&&

.UPDATE...
Issued at 950 PM EDT Tue Oct 22 2019

I updated our grids and zone forecast to have much higher pop
closer to the lake shore through about midnight. This is typical 
of lake effect showers, once the sun sets they tend to propagate 
toward the lake shore and not extend as far inland. We are seeing 
this happen this evening. Helping this too it the wind in the 
cloud layer has decreased some and will continue to decrease as 
the systems moves slowly away from the area. The deep moisture 
does move north of our area by midnight so I would expect the 
showers to diminish considerably by 2 to 3 am. 

Winds will slowly become less gusty inland overnight too, now
through we are still seeing gusts to 30 and 40 mph at airport
sites and more like 15 to 25 mph at other sites. 

&&

.DISCUSSION...(This evening through next Tuesday)
Issued at 328 PM EDT Tue Oct 22 2019

The low centered near Lake Superior will move toward Hudson Bay
 over the next 24 hours but lakeshore flooding impacts will 
continue into Wednesday morning unfortunately given an extended 
period of gale force wind gusts along the coast. Several reports 
of 45 to 55 mph wind gusts have been observed as well as widely 
scattered power outages. 

What we have observed from our survey team today is some of 
the same areas that received beach erosion and bluff collapse 
last week are experiencing additional impacts with 5-10 ft or 
more of erosion on top of last week's losses. The hardest hit 
areas are expected to be near and north of Port Sheldon where 
erosion will continue along with flooding of river mouths and 
low lying parking lots, roads, and potentially some homes as 
well. The threat winds down early Wednesday morning.

Continued over-lake instability, deep cyclonic flow and 
abundant low level moisture will help fuel bands of rain 
showers across the region, though any given location will 
not be raining continuously. Given the propagation speeds 
of these showers, even locations well inland will get 
hit-and-miss precipitation through tonight. This activity 
winds down quite a bit Wednesday. However, showers are 
possible Wednesday night into early Thursday morning as 
we get brushed by a 40 kt LLJ centered from IN to OH and 
are impacted by weak surface troughing.

I believe rain chances are looking more likely late Saturday 
into early Sunday based on an ensemble analysis. The 
deterministic ECMWF and GEM have already been showing a 
Gulf-based low ejecting north toward Michigan for multiple 
runs but the GFS has not. The ECM members tell the real story 
though with most of the 51 members showing this system impacting 
our area. The GFS, in all likelihood, will prove too far east 
with the handling of this system (it takes the low up the East 
Coast). Our current POPs are 30% given our blended model solution 
for the weekend but we will likely be trending higher with time if
the ensemble guidance continues to suggest impacts.

Additional impactful weather is possible by the middle of next 
week as we round out October, but the range of solutions is large. 
Temperatures may be cold enough for wintry precipitation as we 
get closer to Halloween, but details are unclear at this point.

&&

.AVIATION...(For the 06Z TAFS through 06Z Wednesday night)
Issued at 1218 AM EDT Wed Oct 23 2019

VFR conditions are forecast at all the terminals overnight and
through Wednesday evening. Southwest winds will gust at times to
around 20 to 25 kts into Wednesday afternoon. Winds will subside
Wednesday evening. Another system will bring showers late
Wednesday afternoon through Wednesday evening but conditions will
remain VFR through 06Z Thursday. 

&&

.MARINE...
Issued at 328 PM EDT Tue Oct 22 2019

The Gale Warning and Lakeshore Flood Warning still look to be in
good shape. Widespread gales have been observed and we are seeing
continued erosion of dunes and the risk for bluff collapses given
a long duration gale event with waves approaching or exceeding 10
feet in places. The worst has likely either occurred or is
currently occurring as of this writing. But the gradual eating
away of dunes will be a real problem for coastal properties into
early Wednesday. Wave action does subside into the 4 to 6 foot
range Wednesday afternoon, which is still high, but shouldn't
cause too much impact to the dunes and bluffs. 


&&

.GRR WATCHES/WARNINGS/ADVISORIES...
MI...Lakeshore Flood Warning until 8 AM EDT this morning for MIZ037-
     043-050-056-064-071.

LM...Gale Warning until 8 AM EDT this morning for LMZ844>849.

&&

$$

UPDATE...WDM

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