Area Forecast Discussion
Issued by NWS Grand Rapids, MI

Home | Current Version | Previous Version | Graphics & Text | 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 240532
AFDGRR

Area Forecast Discussion
National Weather Service Grand Rapids MI
132 AM EDT Sun Mar 24 2024

.KEY MESSAGES...

- Won`t Feel Like Spring Tonight

- Rain Monday Into Tuesday

- Dry Stretch of Weather Mid To Late Week

&&

.DISCUSSION...
Issued at 257 PM EDT Sat Mar 23 2024

- Won`t Feel Like Spring Tonight

First off, the snow pack is absolutely being torched today by the
"strong March sunshine." The higher sun angle is working overtime
and the GRR snow depth has gone from 6 inches at 800am this
morning to around 1 inch as of 300pm. What remains of the snowpack
though will aid in providing a cooler than normal night through
radiational cooling processes. Our lows tonight range from the
middle teens along portions of U.S. 10 to near 20 elsewhere.
Normal lows for tonight are in the lower 20s to upper 20s from
north to south so we will be 5 to 15 degrees below normal.

Mainly dry weather is expected until the rain arrives on Monday,
but there is a chance for a bit of light snow Sunday afternoon
into Sunday night in a warm air advection wing of precipitation
ahead of a strong Plains low. This is best seen in an 850mb temp
surge which ramps from -12C near Ludington at 800am Sunday to +1C
by 200am Monday. Not out of the realm of possibilities to see a
light dusting of snow up towards Big Sable Point Sunday. Otherwise
the focus is on rain chances to begin the work week.

- Rain Monday Into Tuesday

Water vapor imagery shows a west coast trough this afternoon with
a mid level shortwave heading for the California coast. This wave
works its way to the Plains states on Monday and is pivoting
northeast through the Great Lakes on Tuesday. At the surface a
deep low forms initially with a depth of around 980mb sliding east
out of Colorado. The low fills as it moves our direction into the
990s on Monday in Iowa and remaining at that depth as it moves
north into Canada on Tuesday.

Rain is forecast to break out ahead of the low and move into Lower
Michigan on Monday. Surface dew points nose up into the upper 40s
ahead of a cold frontal passage on Tuesday. 850mb dew points reach
+4C or +5C. These moisture values are very marginal for thunder,
so we should be just looking at a rain event. Likely rainfall
totals will be in the 0.30 to 0.65 range which is a blend of the
wetter GFS and drier ECWMF. Obviously no hydro concerns with those
totals.

Highs on Monday and Tuesday should push well into the 50s. Around
60 is in the forecast down towards I-94 both days.

- Dry Stretch of Weather Mid To Late Week

High pressure settles in during the Wednesday through Friday time
frame and we should largely be dry. We could be looking at a short
window of lake generated precipitation, including some snow
potential on Wednesday in the wrap around cold air advection
regime.

&&

.AVIATION /06Z TAFS THROUGH 06Z MONDAY/...
Issued at 117 AM EDT Sun Mar 24 2024

The risk for low level wind shear will need to be monitored for
Sunday. A low level jet will be forming upstream in the middle MS
Valley today. This feature will track towards MI tonight. Thus an
increased potential for wind shear may develop.  The main window
for this to happen will be after 03z Mon.

High pressure was centered over northeast Lower MI at this time.
Subsidence associated with this feature continues to support dry
conditions through a deep layer of the atmosphere. The 00z Sun
sounding from KAPX shows this nicely. This system will build east
today as a low pressure system deepens over eastern CO. Mid to
upper level moisture will start to increase here in MI as this low
starts to head towards the central Plains. VFR conditions will
continue as the low levels of the atmosphere will remain
relatively dry.




&&

.MARINE...
Issued at 257 PM EDT Sat Mar 23 2024

High pressure drifting through the Great Lakes tonight will bring
light winds and a lack of wave action. Those conditions will
persist into the day on Sunday as well as the high drifts east.
Sunday night the game changes a bit as stronger southeast winds
begin to crank up ahead of a fairly deep plains low. The low will
track from Kansas into Wisconsin from Monday into Tuesday. Winds
Sunday night from the southeast will veer to the south on Monday
and eventually southwest on Tuesday.

No headlines needed tonight or Sunday obviously. Sunday night
into early next week though we will need marine headlines in the
strengthening southerly flow. Mixing warm air advection winds to
the surface this time of year is difficult, but given the strength
of the low we are looking at Small Craft Advisories certainly.
Gales are possible and we will be ascertaining which headline is
the correct one as we head into tonight and Sunday.

&&

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

&&

$$

DISCUSSION...Duke
AVIATION...MJS
MARINE...Duke


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