000
FXUS63 KGRR 011927
AFDGRR

Area Forecast Discussion
National Weather Service Grand Rapids MI
327 PM EDT Sat Apr 1 2023

LATEST UPDATE...
Discussion/Marine/Hydro

.DISCUSSION...(This evening through next Saturday)
Issued at 327 PM EDT Sat Apr 1 2023

-- Winds diminishing this evening --

40 to 50 mph wind gusts associated with a mesolow traversing down
the Lake Michigan shoreline will weaken this evening. Winds will
go nearly calm by the middle of the night as a center of high
pressure moves overhead. Currently a sharp clearing line from
Mackinac to south of Green Bay. Generally expect skies to clear
overnight though some of the short term guidance holds on to
enough low level moisture for pockets of lingering clouds.

-- Low chance of precip Sunday night --

South winds will begin the return of milder air on Sunday. High to
mid level clouds will increase during the day, especially with
greater northward extent, as low pressure approaches Upper
Michigan. Will have low chance PoPs for a passing rain shower in
Central Michigan for late Sunday evening. The greater potential
for precip will be in northern Michigan.

-- Midweek Midwest cyclone --

There has been a strong signal among the ensembles for another
high-impact low-pressure system developing over the Plains to
Midwest from Tuesday to Wednesday. First is a chance of rain
showers, perhaps a rumble of thunder, Monday afternoon through
night as 850-700 mb moisture transport convergence increases. Then
thunderstorms become likely Tuesday night as an expansive and
strong wind field develops over the region, bringing a warm front
through our area. Model forecast soundings show sufficient mid-
level lapse rates above low-level jet transported moisture for a
possibility of severe hazards (hail/wind). Additional swaths of
rain may also renew hydrology concerns.


&&

.AVIATION...(For the 18Z TAFS through 18Z Sunday afternoon)
Issued at 210 PM EDT Sat Apr 1 2023

On the west side of the departing low pressure system, gusty
west winds are shifting north this afternoon while a few passing
showers develop: mostly rain but some locations are mixing over to
wet snow. Ceilings are predominantly MVFR but there are a few dips
to IFR ceilings or visibility. These conditions will continue
until about 00Z, then winds trend lighter into the night and low-
level clouds scatter or clear out completely.


&&

.MARINE...
Issued at 327 PM EDT Sat Apr 1 2023

Northwest gales have been measured at several lakeside anemometers
this afternoon. Gales are expected to subside by 8 PM, but
hazardous waves for small craft will linger through much of the
night. South winds on Sunday will rebuild hazardous waves north
of Grand Haven for the afternoon.

&&

.HYDROLOGY...
Issued at 327 PM EDT Sat Apr 1 2023

Broadly a half inch to an inch of rain fell over the area since 8
AM Friday, but there were also some swaths of 1.5 to locally over 2
inches in the vicinity of a Holland to Alma line and a Paw Paw to
Lansing line. Increasingly efficient runoff, after a March which
had roughly double the normal amount of precipitation, is leading
to rivers rising again, with some of the more commonly flooded
points expected to reach minor flood stage within the coming days.
River forecasts can be accessed at water.weather.gov/ahps

&&

.GRR WATCHES/WARNINGS/ADVISORIES...
MI...Wind Advisory until 4 PM EDT this afternoon for MIZ037-043.

     Wind Advisory until 6 PM EDT this evening for MIZ064-071.

LM...Gale Warning until 8 PM EDT this evening for LMZ844>849.

&&

$$

DISCUSSION...CAS
AVIATION...CAS
HYDROLOGY...CAS
MARINE...CAS

NWS GRR Office Area Forecast Discussion