Truly one for the record books as unseasonably cool air remained
entrenched across the upper Midwest from Julys beginning to end.
simply hard to argue with the temperature numbers below...which show
all stations reported average temperatures running several degrees
below normal across the board. As some may recall in recent months
summary renditions..."normal" is often misused...especially when
looking back historically...a couple degrees either side of what is
considered average occurs a vast majority of the time (in
fact...truly getting "normal" readings is a significant statistical
challenge). However...this month was truly an exception...with
temperatures falling well towards the cool end of the spectrum
(especially daytime highs)...with all stations recording one of
their top coldest Julys on record...and both Houghton Lake and
Gaylord tying or breaking their all-time record. Some other numbers
to show how truly remarkably cool the month was include: the warmest
reading for the month was only 86 degrees...which occurred on the
9th and 10th just north of Onaway (essentially...about what the
daily high temperatures should be for July)...and several overnight
lows in the 30s for some of the typical colder interior locations...
with 33 degrees being the coldest reported...which occurred at
Atlanta on the 5th and 13th. Incredible!
So...why the prolonged cool July. Essentially...Northern Michigan
lied in the perfect (fit your own adjective here if you like)
location as a pair of upper level blocking features...one a strong
area of low pressure centered near the Aleutian Island chain in
Alaska...with another as strong high pressure over the North
Atlantic...forced a direct and nearly unabated feed of cool northern
canadian air into the upper Midwest.
Despite the passage of several rather vigorous cold fronts (go
figure)...the month was remarkably inactive...with no severe weather
reported during the month. Rainfall followed suite...with most locations
reporting below normal precipitation amounts (however...well within
what is considered typical). The one exception was across portions
of Northeast Lower...where rounds of localized heavy rain from the
22nd through the 25th brought amounts up some.
Here is a look at how some locations fared with respect to their
average temperatures during July 2009 (max...min...and mean
values represent average values during the month. Normal values used
to calculate departures are from the 30 year period of 1971-2000):
SSM HTL APN TVC GLR* ALL
July max 2009 69.1 73.9 73.7 74.4 71.4 72.5
max departure -6.6 -6.1 -5.3 -6.8 -8.6 -6.7
July mean 2009 60.3 62.0 63.0 64.1 61.3 62.1
mean departure -3.6 -4.7 -3.7 -5.5 -6.2 -4.7
July min 2009 51.6 50.2 52.2 53.8 51.2 51.8
min departure -0.4 -3.2 -2.3 -4.1 -3.8 -2.8
*unofficial data (observed temperature data is from automated
surface observing system (asos) and normal data is compiled from
cooperative observer sites in vicinity of asos sites)
-With an average July temperature of 60.3 degrees at Sault Ste Marie
...this was the 5th coolest July since 1888.
-With an average July temperature of 62.0 degrees at Houghton Lake
...this tied for the 1st coolest July since 1917.
-With an average July temperature of 63.0 degrees at Alpena
...this tied for the 4th coolest July since 1917.
-With an average July temperature of 64.1 degrees at Traverse City
...this was the 3rd coolest July since 1896.
-With an average July temperature of 61.3 degrees at Gaylord
...this was the 1st coolest July since 1952.
Here is a look at how some locations fared with respect to liquid
precipitation (rain and melted frozen precipitation) during July
2009 (normal values used to calculate departures are from the 30
year period of 1971-2000):
SSM HTL APN TVC* GLR**
total precipitation (in) 1.96 2.54 3.78 2.34 1.39
departure from normal -1.18 -0.21 +0.61 -0.80 -1.83
*unofficial data (observed precipitation is from the cooperative
observer site in the vicinity of the asos site and normal
precipitation data is compiled from the asos site)
**unofficial data (observed and normal precipitation is from the
cooperative observer in the vicinity of the asos site)
Here are some of the more notable weather events during July 2009:
-July 1st through the 3rd...a sign of things to come as persistent
northwest winds brought the first of many unseasonably cool
airmasses into the great lakes region. High temperatures all three
days stayed in the 60s (a good ten or more degrees below normal)...
with several locations staying in the 50s for at least one of the
days in this period.
-July 4th...probably a little chilly for most for the Nation's
Birthday (highs generally in the low to mid 70s)...but all in
all...a rather enjoyable day with mostly sunny skies and low
-July 7th...another southward surging mass of cold air (thanks
Canada!) kept temperatures more like late September and early
October...with highs taking the plunge back into the 50s and
60s...and overnight lows in the upper 30s into the 40s.
-July 10th...isolated storms training over far northwest sections
of Chippewa County brought rainfall amounts of 2.50 to 3.00 inches.
-July 22nd...afternoon storms brought locally heavy rain to parts of
Northeast Lower Michigan...with central Montmorency county taking
the brunt of the action. A trained spotter in Atlanta reported 2.99
inches of rain in only a couple hours. This was more rain than most
of Northern Michigan received during the entire month.
-July 23rd...unseasonably strong low pressure drifting across the
Northern great lakes brought heavy rain once again to portions of
Northeast Lower Michigan...with Alpena setting a daily record
rainfall of 1.43 inches.
-July 24th and 25th...heavy rains targeted areas north of the Mighty
Mac...with several locations recording well over an inch...including
1.53 inches at Pickford.
Here are daily temperature and precipitation records that occurred
during July 2009 (of note...you will see no mention of record high
temperatures or record warm overnight lows...go figure :)):
-A record low maximum temperature of 62 degrees was set at the
Roscommon County Airport in Houghton Lake on July 2nd. This broke
the record of 63 degrees last set in 1929.
-A record low temperature of 36 degrees was set at the Roscommon
County Airport in Houghton Lake on July 13th. This tied the old
record of 36 last set in 1940.
-A record low maximum temperature of 59 degrees was set at the
Roscommon County Airport in Houghton Lake on July 18th. This crushed
the record of 65 degrees last set in 2000. In addition...the high of
59 degrees was the 3rd coldest high temperature reading ever
recorded in the month of July (coldest is 57 degrees).
-A record rainfall of 1.28 inches fell at the Roscommon County
Airport in Houghton Lake on July 22nd. This broke the old record of
0.59 inches last set in 1991.
-A record rainfall of 1.47 inches was set at Alpena on July 23rd.
this broke the old record of 1.27 last set in 1975.
-A record low maximum temperature of 58 degrees was set at Gaylord
Regional Airport on July 2nd. This broke the old record of 62
degrees last set in 1929.
-A record low maximum temperature of 58 degrees was set at Gaylord
Regional Airport on July 7th. This broke the old record of 60
degrees last set in 2004.
-A record low maximum temperature of 57 degrees was set at Gaylord
Regional Airport on July 18th. This broke the old record of 63
degrees last set in 1909. in addition...the high of 57 degrees was
the 4th coldest high temperature reading ever recorded in the month
of July (coldest is 54 degrees).
For additional climate information including up to date local
climate graphics...seasonal outlooks...and El Niño information...
please visit the following websites:
Gaylord National Weather Service
Climate Prediction Center
El Niño and La Nina information
For more information...contact the Gaylord National Weather Service
at (989) 731-3384...extension 726 or 766.