Volume 11 Number 5 | May 1998 |
May was indeed a unique month for weather across the state. Large anomalies in both temperature and precipitation, along with the limited visibility and health warnings issued due to the haze and smoke transported into Texas from the forest fires in Mexico and Central America, made the month quite memorable -- and certainly made it one for the record books. First-order stations across Texas averaged maximum, minimum and mean temperature departures of 5.9F, 2.6F and 4.2F respectively. Many of these stations approached, if not eclipsed, their record monthly temperature for May. The daily temperature records which were set or tied throughout the month are include in a table on the next page. Regarding rainfall, the average percent-of-normal precipitation for the first-order stations was only 10%. Combined with the dry conditions observed in April, rainfall has been scarce throughout the entire spring.
The preliminary temperature and precipitation ranks produced by the Climate Prediction Center help to place May conditions for regions of the United States into perspective. These ranks compare this year's weather conditions to the previous conditions observed over the last 102 years, with "preliminary" meaning that the data from cooperative stations have not been incorporated into the ranking. Texas is included within a region including Kansas, Oklahoma, Arkansas, Louisiana and Mississippi. May 1998 has been ranked as both the warmest and the driest May that this region has ever seen. For the period of March through May, preliminary methods show that this three month period in 1998 ranks as the seventh driest. Temperatures, with a rank of 66 for the season, are considered near-normal, falling just below the upper threshold of this middle tercile.
While the lack of precipitation during May has obvious consequences for agriculture and other dependent fields, May proved to be a prime example of showing what other consequences exist with limited rainfall. With little cloud cover, more radiation reaches the Earth's surface, causing atmospheric temperatures to be higher due to the greater amount of absorbed energy. Also, without precipitation, there is not as much soil moisture. The result is less evaporative cooling -- the energy from the solar radiation goes directly into heating the surface, and consequently the air, rather than evaporating the water. After examining these consequences of little rainfall, it is not surprising that the extremely dry conditions of May were accompanied by the extreme positive anomalies observed in the monthly temperatures.
Smoke began to enter Southern Texas on the 12th, and over the next two weeks, the entire state was affected by limited visibility and health cautions. At some locations, concentrations exceeded three times the accepted limit defined by the EPA. Yet another consequence of the dry spell unfolds. Rainfall is the most efficient remover of pollutants from the atmosphere -- without the rain, contaminants were not washed out. The lack of rainfall, persistent high pressure and a low temperature inversion all helped to trap the smoke and haze near the surface, allowing the contaminents to linger in the atmosphere for extended periods of time.
Prepared by: John F. Griffiths (State Climatologist)
Brian N. Belcher (Graduate Assistant)
belcher@tamu.edu
PREVIOUS DATE STATION VARIABLE TEMPERATURE RECORD 2 May Del Rio Maximum Temp 103F 101F 6 May Dallas/Fort Worth Maximum Temp 100F 95F Del Rio Maximum Temp 105F 104F 7 May Corpus Christi Maximum Temp 93F 90F Austin Maximum Temp 102F 97F Waco Maximum Temp 98F 95F Del Rio Maximum Temp 106F 104F San Antonio Maximum Temp 100F 99F College Station Maximum Temp 99F 94F Houston Maximum Temp 94F 93F 9 May Corpus Christi Maximum Temp 100F 91F Austin Maximum Temp 97F 96F Victoria Maximum Temp 99F 96F Brownsville Maximum Temp 97F 93F Houston Maximum Temp 94F 92F 14 May Midland** Maximum Temp 100F 100F 17 May Houston Maximum Temp 93F 92F Midland** Maximum Temp 100F 100F 18 May Houston Maximum Temp 94F 92F 20 May Lubbock Maximum Temp 100F 97F San Angelo** Maximum Temp 102F 102F 21 May Midland Minimum Temp 74F 70F 25 May Corpus Christi** Minimum Temp 77F 77F 28 May Houston** Maximum Temp 96F 96F 29 May Amarillo Maximum Temp 98F 97F 30 May Lubbock Maximum Temp 103F 101F Houston Maximum Temp 97F 96F College Station Maximum Temp 98F 97F Midland** Maximum Temp 102F 102F Austin** Maximum Temp 97F 97F 31 May San Angelo Maximum Temp 102F 101F Del Rio Maximum Temp 106F 105F Austin Maximum Temp 99F 98F Midland Maximum Temp 106F 102F Abilene Maximum Temp 103F 102F San Antonio** Maximum Temp 98F 98F Houston** Maximum Temp 98F 98F College Station** Maximum Temp 100F 100F ** record was tied, but not broken
Avg Avg Abs Abs No. of Total % of Gr'st Max Min Mean Max Min Days Pcpn Avg 24 hr Station Temp Dep Temp Dep Temp Dep Temp Temp Precip (In) Pcpn Pcpn HDD* CDD*
Abilene 93.4 9.0 64.9 3.8 79.2 6.5 103 50 4 0.72 24% 0.44 0 446 Amarillo 84.8 5.7 53.5 1.9 69.2 3.8 101 40 3 0.53 21% 0.52 40 177 Austin 91.2 6.5 68.5 2.0 79.9 4.3 102 58 1 0.73 15% 0.73 0 470 Brownsville 90.9 3.1 72.1 0.1 81.5 1.6 97 62 0 0.00 0% 0.00 0 518 College Station 91.1 7.1 67.5 2.5 79.3 4.8 100 52 2 0.11 2% 0.07 0 429 Corpus Christi 89.0 2.8 70.1 0.6 79.5 1.6 100 57 0 0.00 0% 0.00 0 456 Dallas/Ft. Worth 89.8 6.9 67.1 4.5 78.5 5.7 101 54 3 2.38 49% 1.27 0 425 Del Rio 96.8 8.6 71.6 5.3 84.2 6.9 106 61 1 0.08 4% 0.08 0 603 El Paso 89.6 2.5 59.2 2.7 74.4 2.6 98 46 0 0.00 0% 0.00 0 299 Galveston 82.7 2.9 72.9 1.1 77.8 2.0 89 67 1 0.02 1% 0.02 0 405 Houston 90.3 5.7 67.0 2.6 78.7 4.2 98 56 1 0.04 1% 0.04 0 429 Lubbock* 90.0 6.9 58.0 2.2 74.0 4.6 103 44 1 0.04 2% 0.04 3 302 Midland* 96.0 8.6 62.0 3.9 79.0 6.2 106 52 1 0.02 1% 0.02 0 443 Port Arthur 86.8 2.7 68.1 1.8 77.4 2.2 96 56 1 0.08 1% 0.08 0 393 San Angelo 95.9 8.5 64.0 2.9 80.0 5.8 103 48 1 1.75 58% 1.75 0 471 San Antonio 91.4 6.1 68.2 2.5 79.8 4.3 100 58 1 0.34 8% 0.34 0 467 Victoria 89.6 4.3 68.6 0.9 79.1 2.5 99 59 1 0.01 0% 0.01 0 446 Waco 91.0 6.6 66.1 1.9 78.6 4.3 100 50 2 0.55 12% 0.53 0 427 Wichita Falls 90.1 6.8 63.2 4.1 76.7 5.5 108 48 1 0.19 5% 0.19 2 369 Shreveport, LA* 89.0 5.8 66.0 4.0 77.0 4.4 102 53 1 0.15 4% 0.15 0 394
*Complete temperature data were unavailable. Temperatures are rounded to the nearest whole degree. X indicates data were not available at publication time. It will be updated when data are available. *HDD - Heating Degree Day: Refer to the Monthly Average chart for a definition T=Trace(<0.005") *CDD - Cooling Degree Day: Refer to the Monthly Average chart for a definition M: Information not available
CLIMATIC AVERAGES FOR JUNE
Rec Rec Gr'st Gr'st Mean # of Days Avg Avg High Low Avg Mon 24hr Pcpn Max Min Max Min Pcpn Pcpn Pcpn Max T Min T >or= Station Temp Temp Temp Temp (In) (In) (In) >90F <32F 0.01" HDD* CDD*
Abilene 91 69 109 47 2.86 9.60 3.66 19 0 6 0 456 Amarillo 88 61 108 42 3.70 10.73 6.15 12 0 8 6 279 Austin 91 72 105 53 3.72 14.96 6.50 21 0 6 0 489 Brownsville 91 75 102 60 2.73 13.06 8.18 23 0 6 0 540 College Station 90 71 106 53 3.68 12.63 6.00 21 0 7 0 471 Corpus Christi 90 73 101 58 3.38 13.35 5.65 19 0 6 0 507 Dallas/Ft Worth 92 70 113 51 2.98 8.75 3.15 19 0 6 0 480 Del Rio 94 72 112 55 2.11 5.74 2.57 24 0 5 0 531 El Paso 97 64 111 46 0.67 3.18 1.56 26 0 3 0 462 Galveston 85 77 99 57 4.44 15.49 12.56 1 0 7 0 483 Houston 90 71 103 52 4.96 16.28 10.35 19 0 9 0 462 Lubbock 90 64 108 44 2.75 7.95 5.70 18 0 7 0 366 Midland 93 66 109 47 1.55 3.93 2.54 20 0 5 0 432 Port Arthur 89 72 100 56 5.59 18.90 10.20 17 0 8 0 471 San Angelo 93 66 110 48 2.33 6.01 2.86 21 0 5 0 435 San Antonio 92 73 105 53 3.81 11.95 6.30 22 0 6 0 516 Victoria 91 73 100 59 4.89 12.68 9.30 20 0 8 0 501 Waco 92 71 109 52 3.28 12.06 4.21 22 0 6 0 495 Wichita Falls 92 68 117 51 3.52 8.60 5.36 21 0 7 0 444 Shreveport, LA 90 69 101 52 3.54 17.11 7.06 18 0 8 0 444
Sunrise/Sunset |
SUNRISE | SUNSET |
DAYTIME LENGTH |
| 1st | 6:33 AM CST | 8:36 PM CST | 14hr 03min |
| 30th | 6:35 AM CDT | 8:45 PM CDT | 14hr 10min |
Moon Phases |
NEW | FIRST QTR. |
FULL | LAST QTR. |
| 23rd | 1st | 9th | 17th | 10:52 pm CDT | 8:46 pm CDT | 11:19 pm CDT | 5:40 am CDT |
Records are at the current site, other records may have occurred at previous sites.
*CDD - Colling Degree-day: The difference between the mean individual daily temperature and 65F, with one
CDD resulting for each degree above the standard 65F during one day.
*HDD - Heating degree-day: The difference between the mean individual daily temperature and 65F, with one
HDD resulting for each degree below the standard 65F during one day.
All times given for sunrise, sunset, and moon phase times are calculated for the intersection of
meridian 99 10'W and parallel 31 23'N, which is the approximate geographic center of the state.
Monthly Weather Outlook for JUNE 1998
The 30-day outlook for the month of June indicates that precipitation will most likely be near to slightly below normal for the entire state of Texas. As for temperatures, the area north of a line connecting Del Rio, Austin and Port Arthur is expected to be near normal. South of this line, probabilities of observing a warmer than normal June gradually increase into the Lower Valley, where a 40 % chance of above normal temperatures exist.
Past Weather Events in June:
June 27, 1957: Hurricane Audrey. The eye of the storm crossed the Gulf coast near the Texas-Louisiana line. Orange was in the western portion of the eye between 9 and 10 a.m. In Texas, nine lives were lost, 450 persons injured: property damage was $8 million. Damage was extensive in Jefferson and Orange Counties, slightly less in Chambers and Galveston Counties. The maximum sustained wind speed reported in Texas was 85 mph at Sabine Pass, with gusts to 100 mph.
June 11, 1965: Torrential rains of up to 8" in two hours near Sanderson (Terrell) caused a major flash flood that swept through the town. As a result, 26 persons drowned and property losses were estimated at over $2 million.
June 20, 1980: A line of severe thunderstorms moved through North-Central and Northeast Texas, bringing high winds, baseball-sized hail, and at least three tornadoes. One tornado near Clifton (Bosque) destroyed two barns and killed 3500 turkeys. Numerous trees and power lines were knocked down, and three barns were set ablaze by lightning strikes.
Agricultural Weather Highlights
Soil moisture came up short throughout May in all Texas Districts. In East Texas stock ponds were looking low and rain was on demand to compensate for abnormally high temperatures. Far West, Central, Southeast and Southwest Texas were all in extremely short order of rain. Corn and sorghum among other crops suffered moisture stress. Parched pastures of Southwest Texas have seen a good three months since they've experienced a noteworthy rainfall.
"This was one of the driest springs in a long, long time," said George Bomar, an Austin meteorologist in a quote to the Dallas Morning News. Every corner of this state is in some stress."
Although ranches and farms are suffering, Texas Water Development Board told the Dallas Morning News that lake levels and stream flow are normal.
Bomar credits this to the amount of rainfall in late 1997 and early '98, which consequently softened the blow of drought conditions. "We're in great shape to confront a drought," said Bomar.
In other Ag news, Presidio County in Far West Texas experienced a major range fire consuming 50,000 acres. Also in Far West Texas, Brewster and Jeff Davis counties had their own range fires to put out. Despite hot winds and hazy skies, crops such as peaches, pecans and tomatoes appeared to be doing well.
Peaches in East Texas came off the trees a bit smaller than usual as a result of dry conditions. Fire ants and grasshoppers gave Southeast vegetable growers some trouble in late May.
West Central Texas won the prize for weather diversity in the state. The first part of May they suffered the hazy skies resulting from Central America's fires. Towards the very end they received 4.5" of rain throughout the area. This was followed by hail and tornadoes, which ravaged some of the district's sorghum fields.
The Coastal Bend region experienced multiple insect problems in conjunction with the overall drought stress. Aphids and leaf miners were in the cotton fields doing their dirty work and the pecan casebearers left their damaging marks on the pecans.
Source of crop and livestock status:Texas Agricultural Extension Service, USDA, Dallas Morning News
Christine S. Diamond
Agricultural Journalism & Horticultural Science
Class of '98
Texas A&M University