Monthly Climatological Summary
Norman 3SE, Cleveland Co., OK (Lat 35^10'57"N, Lon 97^25'27"W, elev 1130)
May 2001
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Temperature Precipitation Snow AM PM
Max Min Water Snow Depth Wx Wx
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01 85.1 58.8 .00 0.0 0 SCT BKN
02 84.0 65.3 .00 0.0 0 BKN BKN
03 81.3 67.8 .02 0.0 0 -RA OVC
04 78.6 60.6 .53 0.0 0 OVC +TSRA
05 75.6 61.9 .05 0.0 0 -DZ BKN
06 77.9 55.0 1.55 T 0 OVC +TSRA GR
07 70.5 52.2 .21 0.0 0 BKN +RA
08 78.3 46.6 .00 0.0 0 SKC FEW
09 82.9 56.8 .00 0.0 0 BKN SCT
10 83.3 65.7 .01 0.0 0 -TSRA SCT
11 82.9 61.5 T 0.0 0 BKN -SHRA
12 81.7 57.0 .00 0.0 0 SCT SCT
13 84.7 59.0 .00 0.0 0 SKC SCT
14
15
16
17 87.3 63.7 .00 0.0 0 BKN
18 .80 0.0 0 +TSRA
19 TSRA
20 85.1 61.5 .50 0.0 0 TS
21 70.3 49.1 .02 0.0 0 -RA SCT
22 77.7 45.5 .00 0.0 0 BKN SCT
23 85.8 58.3 .00 0.0 0 BKN SCT
24 75.2 52.3 .00 0.0 0 TS SCT
25 73.9 47.8 .00 0.0 0 SCT BKN
26 81.9 51.3 .00 0.0 0 SCT BKN
27 89.6 61.2 1.04 0.0 0 SCT +TSRA
28 82.9 60.6 T 0.0 0 -TSRA BKN
29 76.8 67.8 .33 0.0 0 TSRA TSRA
30 85.6 60.4 1.83 0.0 0 +TSRA BKN
31 73.4 58.6 .00 0.0 0 OVC BKN
KEY TO AM/PM WX: SKC - sky clear, FEW - few clouds, SCT -
partly cloudy, BKN - mostly cloudy, OVC - overcast, RA - rain,
SHRA - rain shower, TS - thunderstorm, TSRA - thunderstorm
with rain, DZ - drizzle, GR - hail.
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Means and Totals for May 2001
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Average Maximum Temperature: 80.5
Average Minimum Temperature: 57.9
Mean Temperature: 69.2
Maximum Temperature: 89.6 (5-27-01)
Minimum Temperature: 45.5 (5-22-01)
Days with max temperature 90.0F+: 0 Year: 0
Days with max temperature <32.0F: 0 Year: 3
Days with min temperature <32.0F: 0 Year: 39
Days with min temperature <0.0F: 0 Year: 0
Precipitation: 6.89 Year: 13.93
Greatest one-day precipitation: 1.83 (5-30-01)
Snowfall: T Year: 1.5
Greatest one-day snowfall: T (5-06-01)
Maximum snow depth at midnight: 0
Days with measureable pcpn: 13 Year: 40
Days with pcpn 1.00"+: 3 Year: 4
Days with measureable snowfall: 0 Year: 1
Days with snowfall 1"+: 0 Year: 1
Days with glaze ice: 0 Year: 5
Days with damaging wind: 3 Year: 8
Days with hail: 1 Year: 2
Days with thunderstorms: 11 Year: 22
Days with fog: 0 Year: 13
NOTICE: All temperatures are in degrees Fahrenheit and all precipitation values in inches. Snowfall totals denoted by an asterisk indicate hail.
Summary....Despite some weather patterns that shut off nearly all thunderstorm activity in the southern Plains for two weeks, central Oklahoma still saw its fair share of thunderstorms in May 2001. Precipitation in central Oklahoma was above average during the month as the region was battered by thunderstorms at the beginning and the end of the month. Tornado sirens were sounded in Norman on the 4th as a line of storms moved overhead. On the 6th, the sirens went off again as a rotating thunderstorm passed just south of this location. Several funnel clouds were sighted south of Norman, and dime-sized hail fell at this location. High pressure kept things for the most part quiet from the 7th-16th, then a brief period of storminess returned to the state from the 17th-20th. A large cluster of thunderstorms hit Norman early on the 18th with gusty winds that did damage to small trees. After a tornado outbreak in eastern Oklahoma on the 20th, a large low pressure center parked over the Great Lakes and sent waves of cool air over the Plains for several days. We were finally able to break free of the low's influence on the 26th, which set the stage for several days of storminess at the end of the month. A large cluster of thunderstorms charged southward from Kansas on the 27th, bringing widespread wind damage to much of Oklahoma. Norman was one of many cities which had trees uprooted, power poles knocked over, road signs blown down, and power knocked out. A line of storms slowly trained over the area early on the 30th, bringing incredible amounts of lightning and rain and causing area rivers to reach flood stage.
Turlock CA had zero rainfall in May - the first May that was totally dry there in many, many years. The lowest May rainfall total I recorded there in the 14 years I kept records was a trace in 1992. The 2000-01 season rainfall total for Turlock remains at 13.39 inches.
My storm chase trip from the 14th-19th had moderate amounts of success. After struggling to get even a cumulus cloud the first three days of the trip, we made up for it the last three days of the trip. On the 17th I saw dime sized hail in southern Kansas and several gustnadoes in northern Oklahoma - gustnadoes are whirlwinds that form along the leading edge of a thunderstorm's gusty winds. They are not considered tornadoes since the rotation doesn't extend all the way to the cloud base but can become quite large and are capable of doing damage. On the 18th we saw a spectacular rotating thunderstorm near the Capulin Volcano in New Mexico. On the 19th we got caught in a minor flash flood in Amarillo TX. I also did a little bit of local storm chasing during the month - on the 2nd and the 27th. On the 2nd I got into a fairly weak storm near Woodward with pea-sized hail. The storm I chased on the 27th actually ended up chasing me. It had an awesome flying saucer/stacked plate appearance. It moved towards me at an incredible speed and despite a frantic attempt to drive south and east to get ahead of it the storm still ran me over. I drove back to Norman on I-40 through blinding rain, non-stop lightning, and a fierce crosswind - passing by 18-wheelers that had been tipped over along the way. Still haven't seen a "real" tornado yet this year, but even if I don't, I can't say I walked away from the 2001 storm chase season empty handed.