Area Forecast Discussion
Issued by NWS Grand Rapids, MI

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FXUS63 KGRR 222027
AFDGRR

Area Forecast Discussion
National Weather Service Grand Rapids MI
327 PM EST Fri Nov 22 2019

LATEST UPDATE...
Discussion

.SYNOPSIS...
Issued at 1238 PM EST Fri Nov 22 2019

- Skies will clear by evening / colder tonight

- Pleasant Weather this weekend / storm system misses SW MI to
  south Saturday

- System passes north of area Monday brings warmer air into area

- A storm system with strong winds more than possible late Tuesday
  into Wednesday. Precipitation type seems to favor mostly rain
  but that is not a sure thing at this point.

&&

.DISCUSSION...(This evening through next Friday)
Issued at 328 PM EST Fri Nov 22 2019

The primary story is the storm event is the winter storm event we
are expecting in the Tuesday afternoon into Wednesday morning time
frame. Other than that, we have a 2 other systems that will move
close to Southwest Michigan prior to the system Tuesday/Wednesday.
The first system is a southern stream system system that will
more than likely track south of our CWA Saturday afternoon and
evening. This is one of those southwest United States closed upper
low systems that gets sheared out. However the retreating northern
stream system is to close to Michigan yet, so it is forced to stay
south. It is not out of the question our SE CWA could see a little
light rain Saturday evening but it should be dry enough to keep
the precipitation south of this area.

The next system is a northern stream system system tracks north
of the Great Lakes Monday, due to much strong Pacific system that
is trying to build an upper ridge over central United States
early next week. That system will bring a little wind and warmer
air with it but precipitation seems unlikely as the mid-level air
is to dry. Northern areas may be close enough to the better lift
to see some sprinkles or flurries from it.

The main event for us is a Pacific system with a 150 to 180 knot
jet core that will dig and fairly deep upper trough over the
western United States early next week. However there are a few jet
segments in this wave train, so while the lead wave comes out at
us the main system energy is still west of us. Yes that does mean
another winter storm event should be expected the following
weekend when the main upper waves gets kicked east. Meanwhile
through the lead wave comes at us in the Tuesday/Wednesday time
frame. Since this is not the main wave, just a shortwave being
ejected out ahead of the main storm which will come later, this
system should move quickly through the area and will not be able
to pull down much cold air. Still it will tap Gulf moisture and
there will be enough cold air north of the system track to bring
an area of wet snow. So just how this storm comes out will decide
where the rain/snow line is. All the models show this as a strong
system, which means there will be strong winds behind it as it
moves away Wednesday. As we get closer to the event we will add
more detail to how this will play out.

The good news is Thanksgiving looks like a good travel day at this
point.






&&

.AVIATION...(For the 18Z TAFS through 18Z Saturday afternoon)
Issued at 1238 PM EST Fri Nov 22 2019

I expect skies to become clear or nearly so by late this
afternoon. Currently MVFR cigs prevail over most of our TAF sites
but visible satellite images show breaks in the clouds over
southwest Michigan and skies clear over most of Wisconsin. Since
the back edge of the polar jet will exit east of this area by mid
afternoon, that will allow more subsidence and that in turn will
clear the clouds. Also low to mid level warm advection will help
that cause too.

The surface high passing over southern Michigan tonight will allow
for clear skies and light winds. The next system will pass off to
the south of Michigan Saturday into Saturday night. The
precipitation should stay south of our CWA but it would not be
impossible for JXN to get some sprinkles from a mid deck cloud
base in the evening. For the most part most of our TAF sites
should see mostly clear to partly cloudy skies (mid clouds) from
the system passing to our south.


&&

.MARINE...
Issued at 1238 PM EST Fri Nov 22 2019

I plan on dropping the SCA with the next forecast issuance during
the mid afternoon as none of our reporting sites have SCA criteria
at this point. The next SCA event is expected on Monday.


&&

.GRR WATCHES/WARNINGS/ADVISORIES...
MI...None.
LM...None.
&&

$$

SYNOPSIS...WDM
DISCUSSION...WDM
AVIATION...WDM
MARINE...WDM


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