Area Forecast Discussion
Issued by NWS Grand Rapids, MI

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary Off
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50

000
FXUS63 KGRR 161120
AFDGRR

Area Forecast Discussion
National Weather Service Grand Rapids MI
720 AM EDT Sat Mar 16 2024

.KEY MESSAGES...

- Rain chances moving in today

- Much colder with snow showers Sunday through Monday

- Chance of Light Mixed Precip Thursday/Friday

&&

.DISCUSSION...
Issued at 325 AM EDT Sat Mar 16 2024

- Rain chances moving in today

The leading edge of the pattern change back to late winter can be
seen on the regional radar imagery, with lighter rain evident across
Nrn Wisconsin and the Western U.P. this morning. This precipitation
is associated with an upper low complex dropping down, and an
associated sfc low north of Lake Superior tailing down into
Wisconsin.

The cold front will press through the area through today, and will
bring some high probability of light amounts of rain to most of the
area. The forcing with the upper wave and strength of the front will
allow for the precipitation. However, the lack of rich and deep
moisture will limit amounts to less than a tenth of an inch.

Shower chances will persist at times through tonight, with p-type
transitioning from rain to snow as the colder air arrives. The upper
low complex will settle over the area, and short waves will be
traversing through the area. Accumulating snow does not looks very
likely as temps will be near freezing, and the core of the coldest
air aloft remains just north of the area.

Forecast soundings indicate that even with inversion heights in the
5-7k ft range, the dgz will barely be saturated. This is what will
keep accumulations from being much more than a couple of tenths of
an inch over grassy areas.

- Much colder with snow showers Sunday through Monday

A few snow showers will continue Sunday, with much of the day not
seeing much accumulation. We do expect that the potential for some
snow accumulations will increase late on Sunday. This is the result
of short waves moving through, and then the upper jet sinking
further south, and deeper cold air arriving late Sunday. This will
allow for more widespread and more intense snow showers.

Cyclonic flow, thermal trough and inversion heights around 5 to 7
kft will mean lake effect snow showers persisting through Monday
night then tapering off Monday in between shortwave troughs. An inch
or less of snow accumulation expected. Another clipper moves through
late Monday night/Tuesday morning in fast northwest flow but
moisture is limited and slight chance POPs for snow showers should
cover it.

- Chance of Light Mixed Precip Thursday/Friday

Complex evolution of the flow regime across the CONUS middle and
late next week with a rex block across the West breaking down and
upper low moving east. There is a lot of uncertainty how this
southern upper low interacts with the northern stream through the
end of the week. There is a weak signal for light mixed precip with
at least some phasing taking place by Thursday and Friday. Even the
chance POPs in the current forecast may be too high given low
confidence in there being much moisture return by that time. The NBM
POPs were not tweaked, but may trend lower in the future forecast
updates.

&&

.AVIATION /12Z TAFS THROUGH 12Z SUNDAY/...
Issued at 718 AM EDT Sat Mar 16 2024

VFR conditions will continue through Saturday night. Winds will
gust over 25 knots today. Winds will start out southwest this
morning then go west this afternoon and northwest this  evening.

&&

.MARINE...
Issued at 325 AM EDT Sat Mar 16 2024

The Small Craft Advisory that was issued for today has been extended
through Sunday, and will likely need to be extended even further at
some point.

Lighter winds under ridging that was in place will be ramping up
through today out ahead of the next incoming system. Winds will
initially be from the SW, and then shift to become from the NW by
later today.

Winds and waves will remain up then for most of the time through
Tuesday with colder air filtering in, and multiple waves moving
through.

&&

.GRR WATCHES/WARNINGS/ADVISORIES...
MI...None.
MARINE...Small Craft Advisory until 8 PM EDT Sunday for LMZ844>849.

&&

$$

DISCUSSION...Ostuno/NJJ
AVIATION...Ostuno
MARINE...Ostuno


USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.