Forecast Discussions mentioning any of "ACARS" "MDCRS" "AIRCRAFT" "TAMDAR" "AMDAR" "WVSS" received at GSD on 05/11/22

Area Forecast Discussion

National Weather Service Grand Rapids MI

 1035 PM EDT Tue May 10 2022

LATEST UPDATE...
Update

.UPDATE...
Issued at 1035 PM EDT Tue May 10 2022

We have lowered chances for showers and storms for the rest of
tonight given upstream trends. Chances have been lowered to 20-40
percent the remainder of the night, with the highest chances in
the northwest corner of the CWA up towards Ludington.

A cold front extends from the Door Peninsula in Northeast
Wisconsin, southwest through the state of Wisconsin into Northeast
Iowa. It was thought that this boundary was going to initiate
substantial convection this afternoon and evening, but that has
not happened. Upper ridging leading to subsidence, light surface
winds resulting in weak convergence and a weakening low level jet
make prospects for significant convection overnight fairly small.
Feel leaving in a small chance for a shower or storm is fine
tonight though given MLCAPE values of 1,000 to 2,000 j/kg over
Western Lower Michigan and 3,000 to 5,000 j/kg over Wisconsin.
That said, a fairly substantial cap can be seen in aircraft
soundings this evening. The cap can be seen between 700-800mb via
aircraft at ORD, MKE, GRR and LAN.

We may see some light fog tonight for areas north and west of
GRR. The northern lakeshore areas from MKG up the shore to LDM
will stand the best chance for fog.

&&

.DISCUSSION...(This evening through next Tuesday)
Issued at 345 PM EDT Tue May 10 2022

- Thunderstorms Possible Tonight

While clearly not the most classic set up for thunderstorms
tonight since we do not have strong mid level or even low level
forcing, we do have strong forcing over WI and given the upper
ridge axis is over Michigan tonight, it would seem the storms from
WI will try to move into Lower Michigan after dark then track
south southeast following the mid level thermal gradient.

We do have steep mid level lapse rates over Southwest Michigan
tonight in the range of 7 to 8C. There is some mid level dry air
but it is not so dry as to make the convection upstream dissipate
quickly as it moves our way. Another odd feature is there is a
dew point gradient that moves in from the east. This is from the
southeast winds at low levels, the low to mid 40s dew points over
the extreme eastern part of Lower Michigan are forecast to move
westward tonight and this will set up a low level convergence
zone near US-131 by late this evening, just as these storms move
into the area.

The HREF has 60 to 70 pct pops tonight near and west of US-131 for
this convection and the NAMNEST strongly supports the storm. On
the other hand the RAP/HRRR are not so strongly supporting it
reaching our CWA. I am thinking due to the high mid level lapse
rates, and the low level convergence set up by the dry air moving
in from the east, we have a reasonable risk for a few stronger
thunderstorms with large high and gusty winds (DCAPE is over 1000
j/kg). The storms will not be all that fast moving either, so
locally heavy rainfall is possible too.

Once those storms are done, it should be quiet for awhile but once
the sun comes up there is considerable instability around so any
sort of lake breeze could cause afternoon thunderstorms. These
would be isolated and near US-131.

- Warm and Dry Thursday

The warmest day of this week and likely this month will be
Thursday. That is when the upper ridge is over us and in fact we
close off an upper level high over Michigan. This will mean a lot
of dry air through a deep layer. With the 500 mb heights over 590
dam, and the 1000/925 thickness near 690 dam, high temperatures
will approach 90 degrees in some area, most of our CWA should
have highs in the mid to upper 80s.

- Front comes through Sunday then cooler

The cooler weather will come back and stay around awhile. The MJO
phase went into 6 a few days ago, that is very warm for Michigan.
It is forecast to strongly go into phase 7 next week and that is
cold for Lower Michigan. So, guess what, the cold weather does
come back and based on the MJO should stay around for about a
week.

The cold front for all of this comes through Sunday and at this
point the way it comes through does not suggest a lot of rain but
we will have to see how this plays out.

&&

.AVIATION...(For the 00Z TAFS through 00Z Wednesday evening)
Issued at 827 PM EDT Tue May 10 2022

VFR conditions are in place across the area at 00Z. Scattered
showers and thunderstorms have developed upstream over Wisconsin,
but the coverage is quite limited at this time (much more limited
than earlier expected). It is uncertain whether or not we see
showers/storms move in from the west overnight. At this time
confidence is increasing though that we may end up staying mostly
dry tonight. Therefore, only have VCSH in the TAFs between 03Z
and 10Z. There may be some light fog (MVFR) around late tonight
and around daybreak from 10Z through 14Z. This should not be
widespread and most likely at MKG, GRR and AZO.

There is a chance for scattered showers and storms on Wednesday
across the area, but again coverage will be limited. At this time
have not included precipitation in the forecast for tomorrow
given the low confidence. Winds will be 10 knots or less through
the next 24 hours. Clouds much of the next 24 hours will have
bases between 3,500ft and 8,000ft.


&&

.MARINE...
Issued at 243 PM EDT Tue May 10 2022

We have issued a dense fog advisory for our entire near shore
from 2 am till 8 am Thursday. Already we have 60 degree plus dew
points over Lake Michigan with a surface lake temperature near 40
degree but we do not have much fog yet. That is due to the
stronger winds still over the lake. However, after midnight those
winds decrease significantly as a front stalls over the lake. That
will then allow the fog to develop. The winds once again increase
by mid morning Thursday, that should mix out the fog.


&&

.GRR WATCHES/WARNINGS/ADVISORIES...
MI...None.
LM...Dense Fog Advisory from 2 AM Wednesday to 8 AM EDT Thursday for
     LMZ844>849.

&&

$$

UPDATE...Duke
DISCUSSION...WDM
AVIATION...Duke
MARINE...WDM