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Angie Peltier


Angie Peltier
Former Extension Educator, Commercial Agriculture



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Hill and Furrow

Current topics about crop production in Western Illinois, including field crops research at the NWIARDC in Monmouth.

June and July Weather Summary and July Tornadoes.

Posted by Angie Peltier - Weather

Precipitation. June precipitation at the Northwestern Illinois Agricultural Research and Demonstration Center (NWIARDC) totaled 8.13 inches, more than 3.5 inches above the 30-year "normal" for the month (Table). July precipitation totaled more than 9 inches, nearly 5 inches more than the 30-year normal for the month.

To put these two months into perspective, we can look to the City of Monmouth's 122-year dataset. The NWIARDC is located a little more than 4 miles West of where the City of Monmouth's weather data is currently collected. To put June and July's precipitation totals into perspective we can compare City of Monmouth-collected 2015 monthly precipitation totals to 121 other June monthly totals collected since 1893. June and July 2015 were respectively the seventh and sixth wettest June and July on record.

2015 PRECIPITATION (in inches)

Since January 1

Month

Monthly Total

Monthly departure from average

Total accumulation

Total departure

January

1.32

-0.20

1.32

-0.20

February

1.28

-0.26

2.60

-0.46

March

0.83

-1.70

3.43

-2.16

April

1.21

-2.67

4.64

-4.83

May

4.76

+0.01

9.40

-4.82

June

8.13

+3.64

17.53

-1.18

July

9.04

+4.93

26.57

+3.75

Temperature. The average daily high temperatures were a little below the 30-year "normal" at the NWIARDC for both June (-1 degree) and July (-3 degrees), while average daily low temperatures were a little bit higher than normal in both June (+2 degrees) and July (+1 degree).

June 2015 WEATHER

Soil Temperature

Air Temp

2" (Bare)

4" (Bare)

4" (Sod)

(°F)

Growing Degree Days

-------------------(°F)--------------------

Monthly average high

80

Monthly total: 608.5

80

81

74

Monthly average low

62

67

66

70

Observed high (date)

91 (10)

28 (10)

88 (23)

89 (23)

79 (23)

Observed low (date)

49 (2)

7 (1)

57 (1)

55 (1)

62 (1)

July 2015 WEATHER

Soil Temperature

Air Temp

2" (Bare)

4" (Bare)

4" (Sod)

(°F)

Growing Degree Days

-------------------(°F)--------------------

Monthly average high

82

Monthly total: 696

90

90

80

Monthly average low

64

72

72

74

Observed high (date)

92 (28)

29.5 (13)

89 (31)

101 (31)

85 (28)

Observed low (date)

55 (4)

8.5 (9)

64 (23)

63 (9)

68 (9)

Severe Weather on July 16, 2015. Officials with the National Weather Service's Storm Prediction Center (SPC) collect radar and satellite data and use complex computer models to forecast when and where atmospheric conditions may result in severe weather. A network of trained volunteer storm spotters and professional emergency personnel help to validate conditions on the ground. With guidance from the SPC, who use data to issue weather warnings, each community has a procedure in place for when to sound sirens and warn citizens to take shelter due to severe weather.

EF Scale for Estimating Tornado Intensity. After a tornado event has moved through an area, National Weather Service personnel observe damage to man-made and natural structures in order to develop an estimate of wind speed and assign an "EF" rating. EF stands for "enhanced Fujita" and is named after named Dr. T Theodore Fujita, a researcher and developer of a scale that categorizes tornadoes based upon intensity and area. The EF scale ranges from EF-0, with peak wind speeds between 65 and 85 mph, to EF-5, with wind speeds greater than 200 mph. The enhanced Fujita scale takes into account that not all structures are built to withstand storms equally. Decades of careful study on the degree of damage to one or more of 28 different damage indicators (from a hardwood tree to a two-story home) help experts to estimate peak wind speeds.

The National Weather Service assigns EF values to storms to: gather on-the-ground data over time, to track storm trends and better understand conditions that can lead to these severe weather events. This universal EF scale can also help in better communicating the extent and intensity of tornadoes to the general public.

According to the Storm Prediction Center, on July 16, 2015 there were nine possible or confirmed tornadoes that touched down in five Western Illinois counties (Table). Estimated peak wind speeds for individual events ranged from 80 to 125 mph and were assigned EF ratings of EF-0 to EF-2.

Table. Summary of July 16, 2015 tornado activity in Western Illinois (source: NWS-SPC)

County

Town

Estimated Peak Wind

Path length x width

EF Rating

Henderson

Biggsville

95 mph

0.84 mi x 100 yd

EF-1

Gladstone

Possible Tornado

Rock Island

Port Byron

105 mph

1.2 mi x 200 yd

EF-1

Tazewell

Delevan

1.3 mi x 250 yd

Warren

Cameron

125 mph

8.2 mi x700 yd

EF-2

Kirkwood

90 mph

1.4 mi x 50 yd

EF-1

Kirkwood

120 mph

1.7 mi x 300 yd

EF-2

Monmouth

Possible Tornado

Whiteside

Rock Falls

80 mph

0.55 mi x 10 yd

EF-0

References.

NWIARDC data: Water and Atmospheric Resources Monitoring Program. Illinois Climate Network. (2015). Illinois State Water Survey, 2204 Griffith Drive, Champaign, IL 61820-7495.

City of Monmouth historical weather data: Midwest Regional Climate Center cli-MATE Application Tools Environment

NOAA-NWS-SPC. The Enhanced Fujita Scale (EF Scale).

NOAA-NWS-SPC. SPC Severe Weather Events Archive: July 16, 2015.



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