891
FXUS63 KGRR 121143
AFDGRR

Area Forecast Discussion
National Weather Service Grand Rapids MI
743 AM EDT Mon Aug 12 2024

.KEY MESSAGES...

- Fair weather with milder temps early this week

- Continued dry through midweek then late-week rain

&&

.DISCUSSION...
Issued at 320 AM EDT Mon Aug 12 2024

- Fair weather with milder temps early this week

Skies will be partly sunny today and it will be a little milder
with high temps reaching the upper 70s to lower 80s. Some higher
res guidance including the latest HRRR and the 00Z HREF suggest
isolated showers may develop over our northeast to east fcst area
this aftn where some low level confluence develops. However a
polling of fcst soundings for that area this afternoon looks quite
dry overall. Therefore at this time we will maintain an optimistic
and dry fcst today.

More of the same is forecast for tomorrow and high temps will be
around 2-4 degrees milder than today as a consensus of numerical
guidance has been suggesting for several days now. As forecast
soundings continue to look quite dry once again we will maintain
the dry forecast for tomorrow too. Fcst soundings only show
potential for a sct-bkn fair wx cu deck with cloud bases at around
5 kft agl the next couple of days.

- Continued dry through midweek then late-week rain

A dry/sunny weather pattern with seasonable temps holds through
mid week with sfc ridging in control before changes arrive toward
later Thursday.

Confidence continues to grow for a fairly widespread/substantial
rainfall occurring on Thursday night and Friday. This is when PWATs
greater than 1.75" arrive ahead of an approaching mid level
shortwave and sfc low pressure system. The majority of grand
ensemble members now show over 0.5" 24 hr rainfall amounts with
several showing over 1" and a few even over 2". NBM pops continue to
trend up too and are now 60-70 percent Thursday night and Friday
when what looks to be a sfc occlusion is slowly passing through.

There is also increasing confidence that upper troughing persists
for most of next weekend and even the possibility of a closed upper
low evolving and stalling over the nrn GrtLks Rgn. This would imply
a continuation of scattered showers and isolated tstms over the
weekend within cyclonic flow pattern, although the air mass remains
fairly warm with high temps holding at 75-80 degrees.

&&

.AVIATION /12Z TAFS THROUGH 12Z TUESDAY/...
Issued at 742 AM EDT Mon Aug 12 2024

VFR weather expected today and tonight with scattered to broken
clouds between 5000 and 8000 ft and some high level cirrus clouds
above that. West winds 5 to 10 kts.


&&

.MARINE...
Issued at 320 AM EDT Mon Aug 12 2024

Rather minimal wind speeds and wave heights are forecast early
this week now that the pressure gradient has eased up and cool air
advection is no longer occurring.

&&

.GRR WATCHES/WARNINGS/ADVISORIES...
MI...None.
MARINE...None.

&&

$$

DISCUSSION...Meade/Laurens
AVIATION...Meade
MARINE...Laurens