836
FXUS63 KGRR 180012
AFDGRR
Area Forecast Discussion
National Weather Service Grand Rapids MI
812 PM EDT Thu Oct 17 2019
LATEST UPDATE...
Update/Aviation
.SYNOPSIS...
Issued at 330 PM EDT Thu Oct 17 2019
- Frost and Freezing Temperatures Tonight.
- Small Chances for Rain Saturday Night.
- Impactful system slated for Monday into Tuesday.
- Mon/Tues system to bring thunderstorms on Monday and Wind/Waves on
Tuesday.
&&
.UPDATE...
Issued at 807 PM EDT Thu Oct 17 2019
Skies will be slow to scatter out with the lakeshore to be the
last place. There is some potential for it to remain mostly cloudy
there. Either way the cold air advection should still support
temperatures close to the current forecasted values even if the
cloud hang around for a few more hours. No changes planned to the
headline.
&&
.DISCUSSION...(This evening through next Thursday)
Issued at 330 PM EDT Thu Oct 17 2019
High pressure settles into the Great Lakes region tonight which
will yield a cold night. We are looking at freezing temperatures
tonight away from Lake Michigan and have gone with a Freeze Warning
away from the lakeshore. Lakeshore counties are under a Frost
Advisory. Guidance numbers at Lansing for example are right around
freezing which should result in a fairly heavy frost and a likely
end to the growing season. Guidance numbers at HTL just north of are
area are in the upper 20s. Feel with ridging tonight the cloud cover
will erode after sunset resulting in substantial clearing that will
aid in radiational cooling.
Our next chance for precipitation comes Saturday night with a
weakening cold front. In the end chances look small with this front
and most areas will see little if any rainfall.
We have another strong fall low that will affect the area early next
week. A low around 990mb`s will move through the western Great Lakes
and drive a strong cold front through the area on Monday and Monday
night. The system will be dynamic enough with just enough moisture
to make thunderstorms a possibility ahead of the front. Not sure
there will be enough instability for any severe weather however.
Winds will increase on the back side of the system with strong winds
in place for Monday night into Tuesday. Lake effect rain will be
likely Tuesday into Tuesday night in the cold air advection.
Quieter weather is then expected for Wednesday into Thursday. Siding
with the further west Euro with the Thursday system next week which
would keep us dry until Thursday night.
&&
.AVIATION...(For the 00Z TAFS through 00Z Friday evening)
Issued at 807 PM EDT Thu Oct 17 2019
Slow scattering out of the cloud cover is forecasted. VFR weather
is expected to prevail through Friday. There is a small risk for
patchy early morning fog/stratus...but that risk for too low to
include it in the forecast. The pressure gradient was weakening so
much less in the way of wind is forecasted through Friday.
&&
.MARINE...
Issued at 330 PM EDT Thu Oct 17 2019
Will allow the Small Craft Advisory to continue through 800pm south
of Holland as Cook Nuclear buoy near Bridgman still has waves near 4
feet and there are whitecaps still at South Haven on the GLERL
webcam. Conditions are clearly dampening out and waves will subside
to less than 2 feet overnight.
Our next wave event develops Friday night in southerly flow. We are
likely going to need a Small Craft Advisory north of Holland with 3
to 6 footers likely. The waves will persist north of Holland on
Saturday as well.
The biggest marine item on the docket in the next 7 days is another
strong wind and high wave event in the Monday/Tuesday time frame.
The highest waves will occur on Tuesday, possibly reaching the 7-11
foot range once again. Gale force winds and Lakeshore Flood
headlines would likely be warranted.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...Freeze Warning from 2 AM to 8 AM EDT Friday for MIZ038-044-051-
052-057>059-065>067-072>074.
Frost Advisory until 8 AM EDT Friday for MIZ037-043-050-056-064-
071.
LM...None.
&&
$$
UPDATE...MJS
SYNOPSIS...Duke
DISCUSSION...Duke
AVIATION...MJS
MARINE...Duke
NWS GRR Office Area Forecast Discussion
