The National Drought Mitigation Center released their weekly drought monitor update this morning. These weekly updates are focused on broad-scale conditions and local conditions may vary. Data for the drought monitor updates are updated weekly with the cut-off being Tuesday morning at 6 AM CST. They compile the data on Tuesday and Wednesday with the official outlook released every Thursday morning. Precipitation and conditions after the data cutoff at 6 AM Tuesday are not included in this update.
This week’s drought monitor introduced D0 or abnormally dry conditions to portions of North Texas extending south/southwest into Central Texas through the Concho Valley and Edwards Plateau. These locations generally missed out on rains from Harvey back in August. Additionally, rainfall amounts have been about 50% of normal over the last 60 to 90 days. This has resulted in an increased risk of wildfires along with short-term agricultural impacts. Localized D1 or moderate drought conditions were also added within the broader area. D2 severe drought conditions are now in place across portions of Northeast Texas. We also have abnormally dry to moderate drought conditions across South Texas into the Rio Grande Valley.
The below-average rainfall over the last two to three months combined with vegetation becoming dormant has allowed for an uptick in wildland fires. A 350-acre wildfire last week in Wise County (North Texas) is an example that surface fuels are starting to become more resistant to initial attack activity. Those locations that experienced sub-freezing temperatures over the last two weeks will also start to see vegetation become dormant – and more susceptible to faster fire spread.
The following is a text summary from the NDMC regarding this week’s drought monitor.
“Although western sections of the South were mainly dry, light to moderate (0.5-2.5 inches) rain fell on southeastern Texas, most of Louisiana, eastern Arkansas, and most of Mississippi and Tennessee. Isolated, heavy totals (2-6 inches) were reported in northwestern and central Tennessee and south-central Louisiana. These rains were responsible for some D0 removals, most notably in extreme east-central Texas, south-central Louisiana, and near the intersection of Arkansas, Louisiana, and Mississippi. The light rain was enough for status-quo in Mississippi, eastern Arkansas, and northeastern Louisiana.
With October normally one of the wetter months in central Texas, spotty precipitation during September and October plus this week’s lack of rain made it ideal to expand the D0 across southwestern and central areas into northeastern Texas. Some areas that were already in D0 went to D1 in central Texas, as did extreme northeastern Texas and southeastern Oklahoma (areas that did not receive rain from Harvey). Farther to the north and west (northeastern Texas, western and central Arkansas into southern Missouri) where Harvey rains missed, both 60- and 90-day precipitation has been less than 50% of normal, creating 4-8 inch shortages. Accordingly, where both the 2- and 3-month SPIs and deficits were similar, D2 was added (northeastern Texas, northwestern Louisiana, southwestern and northern Arkansas). In western Oklahoma, the two D0 areas were merged into one (similar 60-day conditions), and although the 30-day precipitation has been extremely dry in western Oklahoma, the Texas Panhandle, and western Kansas, the 60- and 90-day tools were wet, thus holding off widespread D0 deterioration in much of this area for now.”
Widespread precipitation did fall from the Permian Basin and Big Country eastward through North-Central Texas into Northeast Texas and East Texas yesterday. As noted above the data cutoff for the weekly drought monitor is Tuesday morning, so these precipitation totals will be included in next week’s assessment. Rainfall amounts generally vary from one-half inch upwards to one and a half inches. One to two inches of snowfall was observed in the northern Texas Panhandle, but the liquid equivalent (once the snow melted) was under a quarter of an inch. Lighter rainfall was observed farther south into Central Texas and the Brazos Valley. I do not anticipate large-scale changes/reductions in next week’s drought monitor update, but we should see some improvement in areas that received at least one-half inch of rain. Rainfall forecasts for the next week do not look impressive as a relatively zonal/quiet pattern is expected for the upcoming period. Measurable rainfall, perhaps around an inch, may occur across far South Texas and the Rio Grande Valley. Otherwise, any rainfall in the coming week will likely remain under one-half inch across Texas.