May 2011
Report and Summary
Tyler, Texas
May 2011
by Robert K. Peters, Ph.D.
National Weather Service Cooperating Observer
The month of May 2011 saw near normal temperatures and below normal precipitation. May 2011 was 4.0 deg. cooler than May 2010, and 1.04 inches wetter. Year-to-date rainfall through month's end was 0.31 inch greater in 2011 than in 2010.
The thirty-day outlook had called for above normal temperatures and below normal precipitation.
A diffuse storm system crossed between the evening of the 1st and the 3rd, resulting in rainfall and very cool temperatures. Temperatures went above normal on the 6th, remaining there until another system crossed on the night of the 12th. This brought substantial rainfall to the counties along Red River, and those from Angelina eastward to the Louisiana border, along with severe weather on the nights of the 11th and 12th.
Very cool air settled over the region on the 13th, with below normal temperatures continuing through the 17th.
Temperatures warmed on the 18th ahead of an upper air low which began crossing on the 20th. Strong storm systems crossed on the 20th-21st, and again on the 24th-25th. Thunderstorms were widespread in the area on both occasions. The first system resulted in the Joplin, Mo. Tornado on the 21st.
Temperatures continued warm and conditions humid until a cold front reached the area on the evening of the 25th. This brought a respite from high temperatures until warming resumed on the 27th.
Temperatures climbed to well above normal levels between the 27th and 31st, with no precipitation. This happened as upper air high pressure established itself over the region, and a summertime pattern commenced.
- KEY TO SYMBOLS:
- A = HAIL
- B = BLOWING
- D = DUST
- F = FOG
- H = HAZE
- IP = SLEET
- K = SMOKE
- L = DRIZZLE
- R = RAIN
- S = SNOW
- T = THUNDERSTORM
- Z = GREENWICH MEAN TIME
- ZL = FREEZING DRIZZLE
- ZR = FREEZING RAIN
- - = LIGHT
- + = HEAVY
- R FOLLOWING A TEMPERATURE OR PRECIPITATION VALUE = RECORD
The reporting period for temperatures, precipitation, and phenomenon on each day is for the twenty-four hours ending at midnight hours GMT--6 p.m. CST and 7 p.m. CDT. All times are given using the twenty-four hour clock, and are expressed in Greenwich Mean Time.
Observations are from NWS Station 41/9207/4 in Tyler, Texas. The term "normal" refers to averages from the standard climatic period 1971-2000.
.MAY 2011
- 01 89 49 61 0.05 PCPN 2300-0000 Morning Low 72
- 02 52 49 52 0.20
- 03 70 45 66 0.15
- 04 76 44 74
- 05 78 50 76
- 06 85 53 82
- 07 90 61 87
- 08 90 67 87
- 09 94 69 89 H
- 10 89 72 86 H
- 11 85 64 79 Morning Low 70
- 12 78 62 0.82 T, PCPN 0000-0300
- 13 78 58 71
- 14 69 52 66
- 15 73 48 69
- 16 75 52 71
- 17 82 50 79
- 18 82 61 79
- 19 81 67 80
- 20 88 67 76 0.33 T, A, F, PCPN 1700-1800, 2200-2400 Morning Low 74
- 21 83 64 81 0.45 T, PCPN 0000-0300
- 22 91 73 86 H
- 23 87 72 85
- 24 91 73 86 Morning Low 74
- 25 93 72 88 0.20 T, F, PCPN 0500-0600'
- 26 82 62 80
- 27 94 64 91
- 28 98 73 92
- 29 94 71 91
- 30 93 73 91
- 31 92 72 90
MAY 2011, RECORDS AND SUMMARY:
- 2ND, RECORD LOW MAXIMUM 52, PREVIOUS RECORD 60 IN 1978;
- HIGHEST TEMPERATURE 98 ON THE 28TH,
- LOWEST TEMPERATURE 44 ON THE 4TH,
- AVERAGE MAXIMUM 83.9 F.,
- AVERAGE MINIMUM 61.6 F.,
- AVERAGE TEMPERATURE 72.8 F.,
- 0.5 DEG. COOLER THAN NORMAL.
- 36 HEATING DEGREE DAYS,
- 360 PERCENT OF NORMAL HEATING DEGREE DAYS.
- 166 COOLING DEGREE DAYS,
- 61.9 PERCENT OF NORMAL COOLING DEGREE-DAYS;
- TOTAL PRECIPITATION 2.20 IN.,
- 2.26 IN. LESS THAN MONTHLY NORMAL.
- 49.3 PERCENT OF NORMAL MONTHLY PRECIPITATION.
- YEAR-TO-DATE PRECIPITATION 13.55 IN.,
- 5.84 IN. LESS THAN NORMAL YEAR-TO-DATE PRECIPITATION,
- 69.6 PERCENT OF NORMAL YEAR-TO-DATE PRECIPITATION;
- 4 DAYS ON WHICH THUNDERSTORMS OCCURRED;
- 7 DAYS ON WHICH MEASURABLE PRECIPITATION OCCURRED;
- 5 DAYS ON WHICH THE VISIBILITY WAS RESTRICTED TO BETWEEN 1/2 AND 6 MILES BY FOG, SMOKE, OR HAZE;
- 0 DAYS ON WHICH THE VISIBILITY WAS RESTRICTED TO 1/4 MILE OR LESS BY FOG;
- 0 DAYS ON WHICH THE VISIBILITY WAS RESTRICTED BY DUST OR BLOWING DUST;
- 1 DAYS ON WHICH FROZEN PRECIPITATION WAS OBSERVED;
- 0 IN. TOTAL SNOWFALL.
- 10 DAYS ON WHICH THE MAXIMUM TEMPERATURE REACHED OR EXCEEDED 90 DEG.;
- 0 DAYS ON WHICH THE MAXIMUM TEMPERATURE REACHED OR EXCEEDED 100 DEG.;
- 0 DAYS ON WHICH THE TEMPERATURE FAILED TO RISE ABOVE 32 DEG.
- 0 DAYS ON WHICH THE MINIMUM TEMPERATURE REACHED OR FELL BELOW 32 DEG.
- 2191 SEASON-TO-DATE HEATING DEGREE DAYS,
- PERCENTAGE OF NORMAL SEASON-TO-DATE HEATING DEGREE DAYS: 111.9,
- 441 YEAR-TO-DATE COOLING DEGREE DAYS.
- PERCENTAGE OF NORMAL YEAR-TO-DATE COOLING DEGREE DAYS: 106.8,
- PRECIPITATION DURING THE PREVIOUS TWELVE MONTHS 36.21 IN.,
- TWELVE-MONTH PRECIPITATION PERCENTAGE 80.0.