Showers & Storms

Yesterday we reached 56° after a morning low of 26°.

An active frontal boundary will set up across Michigan over the weekend, bringing rounds of showers and possible thunderstorms. Some of the storms on Sunday afternoon and evening could be severe. A sharp temperature contrast will exist across the front, with temperatures ranging from the 30s and 40s in northern Michigan to near 70 south.

Sunday SPC Outlook

Weather History

1904: Heavy rain and temperatures in the 50s during the last week of March combined with the melting of a deep snowpack to cause some of the worst flooding on record along the Grand and Kalamazoo Rivers. About half the city of Grand Rapids is underwater as the river reaches an all-time record crest of 19.6 feet, which was 2 feet higher than the previous record and 4.6 feet above flood stage. Water covered half of the city and flood waters reached 2,500 houses and 14,000 people. Many people suffered from hunger and exposure. Several factories and between 200 and 300 businesses were flooded. Loses totaled $1,800,000. Lansing has the worst flood in 135 years of record. Battle Creek is also inundated by floodwaters.

1920: One of the worst tornado outbreaks in U.S. history strikes from Wisconsin to Georgia, killing more than 150 people. In Michigan, at least a dozen people were killed and hundreds of homes were either damaged or destroyed. The worst hit areas in Michigan included Saint Johns in Clinton County, Maple Grove and Orangeville in Barry County, and Fenton in Genesee County.

On March 28, 1928, a early season tornado outbreak hit Southern Lower Michigan, Indiana and Ohio. 14 tornadoes were recorded in Michigan from Mason and Oceana Counties in West Central Lower Michigan to Genesee and Oakland Counties in Southeast Lower. Three of the Michigan tornadoes were estimated to be as strong as F4 including one that hit Genesee and Oakland Counties. That tornado started near Fenton and moved 10 miles northeast across far northwest Oakland County. Four deaths were recorded from this particular tornado including one person in an overturned car, probably just the second tornado related death in a car at that point in U.S. history. Specifically for Southeast Lower Michigan, tornadoes hit Saginaw, Genesee, Oakland and Shiawassee Counties. In total across the state there were 13 deaths and 59 injuries.

Also on March 28, 1945, the temperature soared to 82 degrees in Detroit.

Forecast Discussion

- Warmer With Showers and Chance of Storms Through Sunday

Elevated showers and thunderstorms are on track to arrive in the
coming hours associated with a warm front surging north across the
state. CAPE looks to be sufficient for general thunder, on the order
of a few hundred joules, but not anything more than that. Poor mid-
level moisture quality will limit widespread precipitation to under
one-quarter inch, through the HREF LPMM suggests isolated pockets up
to one-half inch are possible. Best coverage will be across
southwest lower Michigan becoming more spotty as the front crosses
the area given a diminished frontogenetical response. Highs will
range from the 50s near US10 where the front stalls to near 70
across the I94 corridor.

Saturday will initially feature precipitation limited to the
northern CWA near the front, expanding south through the day as the
front drifts to the south. There will be a notable temperature
gradient across lower Michigan as a result of the front. Uncertainty
is highest across the northern CWA due to high dependence on
specific frontal positioning. The northern CWA is favored to start
in the 50s, but fall back into the 40s/upper 30s by evening. Highs
near and south of I96 (which is approximately where the front will
stall Saturday Night) are favored to remain into the 60s

Sunday, increasing southerly flow drives the baroclinic zone back to
the north with 850mb temps climbing to near 10C. Across southern
Michigan, temperatures will climb well into the 60s again. Central
Michigan will be much more uncertain, reaching the fifties if the
frontal boundary moves north of them (favored by the ECMWF/CMC
families) or staying in the thirties if it stalls across lower MI
(favored by the GFS/NAM families). The GEFS has trended slightly
warmer in the 00z suite which would favor more rain and less of an
icy mix risk. Instability also re-enters the picture Sunday leading
to a attendant thunder risk with widespread rain as the surface low
approaches. One thing we will need to watch is the potential for a
few stronger storms on Sunday. 30-45 knots of shear with MUCAPE
values likely exceeding 500-1000 J/kg may be enough for some
organization of storms, particularly given backed winds along the
warm frontal boundary wherever it sets up.

- Rain Transitions To Snow and Diminishes Sunday Night into Monday

As the surface low departs Sunday Night into Monday, cold air
advection will take hold leading to rain mixing with/changing over
to snow as it diminishes. Some uncertainty exists in how long
precipitation lingers given the GFS suite favors a quickly departing
low, while the ECMWF and CMC suites hold the low and associated
troughing longer keeping precipitation into Monday. Accumulation
chances look to be low, with areas near and north of US10 having the
best shot at seeing any accumulation. Surface and upper-level
ridging then dries out the area for Tuesday.

- Additional Precipitation Mid-Next Week

Our next system arrives Wednesday as a mid-level wave ejects a
surface low through the region once again with high confidence in
some form of precipitation. Ensemble clusters suggest uncertainty in
how this trough interacts with the downstream ridging affecting how
much warm air is advected into lower Michigan. If we end up on the
cooler end of the system highs towards the 40s and light snow or a
rain/snow mix are favored. However if warm air advection is more
robust highs into the sixties and rain are expected once again.

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