284
FXUS63 KGRR 111114
AFDGRR
Area Forecast Discussion
National Weather Service Grand Rapids MI
714 AM EDT Sun Oct 11 2026
.KEY MESSAGES...
- Low clouds and light rain from remnants of Isaias today
- Warm air continues through Monday; Rain chances Tue and Wed
- Chance for showers and storms late this week
&&
.DISCUSSION...
Issued at 230 AM EDT Sun Oct 11 2026
- Low clouds and light rain from remnants of Isaias today
Post tropical cyclone Isaias will bring heavy rainfall through
the southern Appalachians and move through the Mid Atlantic today.
Southeast Michigan remains on the edge of the tropical moisture
and will bring some low clouds to regions south of I 96 and west
of the US 131 today. Best chance for rain will be through the
east of I 69. Overall rainfall will be fairly light.
- Warm air continues through Tuesday; Rain chances Tue and Wed
The warm air conveyor belt will continue through Tuesday. Max
temperatures through this time frame will be 10 to 20 degrees
above normal. Monday`s Max temps are expected to be in the upper
70s to low 80s across lower Michigan. These temps are associated
with a positively tilted upper level ridge, which should keep any
showers north of the lower peninsula through Monday. That ridge
will break down Monday night into Tuesday. so expect a weak upper
level trough to swing a mid level system through the area into
Tuesday. QPF is around 0.25 at this time.
The pattern flattens out Tuesday into Wednesday with a more
zonal trend which could keep the best rainfall on Tuesday north
of US 50. However,the EC ensemble PWATS for that band through
northern lower MI is around 1.5 inches. If that pool of moisture
shifts to the south then locally higher amounts of rainfall could
be possible. Lows will be in the mid 60s by Tuesday morning,
peaking into the upper 70s Tuesday afternoon. So a warm, rain for
the most part.
Depending where the moisture band sets up on Wednesday, the
southern half of lower Michigan could see some decent rainfall
Wednesday, though currently the best PWATS are south of the I 94
corridor.
- Chance for showers and storms late this week
A pattern shift is ahead, though latest mid range guidance
pushes the pattern change to the end of the work week. Any rain
and clouds will temper temperatures through Midweek. Max temps
should remain above normal through Thursday. A cold front late
this week will drop temperatures below normal, bringing more
Autumn-esque temperatures.
The guidance continues to become out of phase beyond Thursday.
The GFS brings a deepening synoptic system through the area
Friday. The EC has a much shallower solution, with any moisture
bands bifurcating the area. The NAEFS and EC ensembles are
similar, which gives more credence that the northern portion of
the system remains through the Upper Great Lakes, and a vort max
associated with the southern portion of the system skirting
through IN and Ohio. That should mean any rain chances Friday
should be south of the I 96 corridor, and heaviest rain south of
Michigan.
&&
.AVIATION /12Z TAFS THROUGH 12Z MONDAY/...
Issued at 708 AM EDT Sun Oct 11 2026
The remnants of Isaias will move through the Mid Atlantic and
moist flow from it should drop cigs to IFR at JXN, LAN, AZO and
BTL. JXn has already dropped to IFR with AZO and BTL at MVFR.
The TAF sites that will see the worst conditions will be JXN and
potentially LAN. AZO should see IFR this morning, before improving
early afternoon. Low cigs will continue through most of the day
at JXN and LAN. Expect improving conditions after 22Z. GRR should
see MVFR cigs but is far north enough to be outside the thickest
low clouds. LLWS is expected through the first few hours of this
TAF cycle but the LLJ will move to the east after 07Z.
The only TAF site that should see rain is JXN, however there is a
low probability chance for VCSH at BTL and LAN.
&&
.MARINE...
Issued at 150 AM EDT Sun Oct 11 2026
The winds and waves continue to weaken and shift to out of the
east, becoming more offshore. Gusts are upwards of 20 to 25 kts
through the northern zones through 09Z so will keep SCA through
that time. Waves will continue to slacken and shift out of the
south today, then southwest tonight. Mot expecting any headline
conditions through Monday.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...None.
MARINE...Small Craft Advisory until 5 AM EDT early this morning for
LMZ846>849.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...None.
MARINE...None.
&&
$$
DISCUSSION...Ceru
AVIATION...Ceru
MARINE...Ostuno
NWS GRR Office Area Forecast Discussion
