Heat – Storms & Smoke

…and once again we have smoke in the forecast and another air quality alert due to Canadian wildfires.  To make things worse the heat and humidity will be in place along with the smoke to make it hard to breathe for sensitive groups and normal people for that matter.  Temperatures will be in the upper 80s to near 90° today with some storms possible east of US 131 (of course).

Tomorrow the SPC has southern Michigan in the outlook for severe storms, an enhanced area from southern Allegan County to the east and south.

---

---

U.S.A and Global Events for July 25th:

1936: Lincoln, Nebraska saw an all-time high temperature of 115 degrees. The low only dropped to 91 degrees and the average temperature was 103. Many people spent the night sleeping outside to escape the heat. Click HERE for more information from Nebraska History.

1956: The Andrea Doria sank in dense fog near Nantucket Lightship, Massachusetts. The Swedish-American liner, Stockholm, hit the ship forty-five miles off the coast of Massachusetts. Fifty-two persons drowned or were killed by the impact. Click HERE for more information from PBS.

2005: The citizens of Sand Point, Alaska saw a rare tornado touchdown on two uninhabited islands. Sand Point is part of the Aleutian Chain and is located about 570 miles southwest of Anchorage.

---

Grand Rapids Forecast

[pdf-embedder url=”https://michigan-weather-center.org/wp-content/uploads/2023/07/7-25-grr.pdf” title=”7 25 grr”]

---

Forecast Discussion

.SHORT TERM...(Today through Wednesday Night)
Issued at 357 AM EDT Tue Jul 25 2023

- Smoke -

Higher concentrations of smoke are located upstream as displayed
by the AirNow PM2.5 page. Some values are in excess of 100 and
this may push in today on southwest winds. The RAP smoke and HRRR
smoke models indicate that this will be the case. That said, these
values are much lower that what we saw earlier this summer where
visibilities were impacted fairly significantly. Bottom line, we
will see smoke today in the sky with the hazy sunshine being very
apparent. An Air Quality Alert remains in place of the entire
area, but we do not expect the values to be as bad as a few weeks
back.

- Today and tonight -

A few showers and storms continue to work there way to the
southeast from portions of Central Lower MI (up towards
Ludington). This activity is associated with a warm front aloft
which will likely continue to produce activity through daybreak.
Activity should diminish through the daylight hours of the
morning. This afternoon, the HREF 4 hour max reflectivity
continues to show some isolated shower and thunderstorm activity
inland (east of Highway 131). The most concentrated area of
showers/storms will be across Central Lower Michigan up towards
Mt. Pleasant and Clare. The lack of shear today will keep any
storms below severe levels. The current activity and the activity
this afternoon is associated and will continue to be associated
with some weak moisture advection seen in both the advancing PWAT
field and moisture transport vectors at 850mb.

- Severe Threat on Wednesday -

The SPC has increased the severe threat for Wednesday to an
Enhanced level. Factors are certainly there for a threat for
severe weather including MUCAPE values that are forecast to rise
potentially to 3,000 j/kg per the HREF. Wind fields by mid summer
standards are elevated with 40 knots of wind in the mid levels and
a low level jet around 30 knots. All of these factors would point
towards a severe threat as does surface dew points around 70F. A
compact mid level shortwave will be moving through the forecast
area on Wednesday so synoptic support is there as well.

What clouds the forecast a bit is how the convection from tonight
evolves upstream and how much of that pushes into the forecast
area Wednesday morning. The HREF shows quite a bit of activity
moving into the area in the morning with showers and storms
continuing through the day. There is a hint in the HREF 4 hour max
reflectivity of a redevelopment around 21Z. That activity then
pushes east through the forecast area.

We certainly need to keep an eye on this time frame for the threat
of severe given the wind fields in play. Wind looks to be the
biggest threat from storms on Wednesday with a tornado threat in
our far Southeast as well towards Jackson. Deep layer shear is on
the order of 50 knots so storms will be organized and likely to
acquire rotation.

Storms will quickly sweep off to the east and south in the evening
where a bigger threat for severe weather may exist just to our
east and south.

.LONG TERM...(Thursday through Monday)
Issued at 323 AM EDT Tue Jul 25 2023

Zonal flow across the northern tier of states will result in another
minor short wave moving across the cwa Friday and Friday night as a
surface low develops over Nebraska and rides east along a nearly
stationary frontal boundary. A period of showers and storms may
develop late Friday and continue into Saturday morning. GFS progs
shear values near 40 kts pointing toward the potential for a few
stronger storms to develop. Forecast soundings show SBCAPE around
1300 j/kg and precipitable water values north of 1.5 inches. DCAPE
near 1200 j/kg owing to drying below 600 mb suggests the potential
for strong winds. Dewpoints in the 70s and highs around 90 will
create very humid conditions.

Once the wave moves east, north winds will return and highs will
return to around 80 for the weekend into early next week. Dewpoints
will also fall into the 50s creating comfortable conditions.
Nighttime lows in the 50s are anticipated from Saturday night
through Tuesday night.