The first full week of Fall is expected to feel just like that!
I’ve made a “four-panel” of some of the things that meteorologists use to determine heavy rainfall potential, and I’ll explain below how we use them.
On the upper left corner, you will see forecast-model derived Precipitable Water. The best way to explain this is to think of the atmosphere like a sponge.
This week, the forecast calls for over 2 inches of precipitable water – which is near the maximum capacity of the atmosphere – and generally means that rain is likely. If the atmosphere can continue to be “fed” more moisture as it is raining (and this is common), then heavy rain and flooding are possible.
The bottom left panel shows the Jet Stream. Generally, the most energy with the Jet stream is found just to the right of the base of the trough – which happens to pinpoint much of Central and West Texas. The trough itself sits over the Western United States and shows where the lowest pressure and coldest air are aloft.
Meanwhile, at Laughlin Air Force Base, weather technicians observe the weather from the ground - 24 hours a day, 7 days a week. These observations are taken hourly - occasionally more often in the case of nearby inclement weather - and much like weather balloon data are transmitted for use into weather forecast models. Since weather only exists because of how the sun heats the surface of the earth unevenly across distance - surface weather observations (which contain a significant amount of weather data, as seen below) are essential to weather forecasting.
Most surface weather observations across the United States are automatic - but these automatic stations don't always provide accurate weather data (such as clouds, visibility, thunderstorms, etc). Because of this, most weather offices and commercial airports visually report the present and approaching weather and clouds while using the weather sensor to calculate pressures, temperatures, and winds.
Due to Del Rio's somewhat remote location, accurate weather observations from Laughlin AFB around-the-clock play an integral piece in monitoring and forecasting weather across a wide region of west, central, and south Texas - and each weather observation is then ingested into global forecasting models which provide pin-point readings of weather data - such as atmospheric pressure and wind speed and direction - which is key to hurricane forecasting - even if it's over a thousand miles away.
Together, whether contracted with the National Weather Service or employed at Laughlin AFB, local weather experts are playing a much larger part in Hurricane Irma support than most Del Rioans could ever imagine.
We never know when the next hurricane may take a path up the Rio Grande and we'll be hoping that other areas of the country are looking out for us - and they will be. In the meteorology world - like many other public service careers - meteorologists are always standing-by, day or night, to observe, forecast, watch, and warn of hazardous weather - and in Del Rio Texas, you've got a great team.
Good Morning, Del Rio!
Below I was able to capture a fantastic satellite image loop from the National Oceanic and Atmospheric Administration's brand new GOES-16 Satellite. As the sun rose this morning, the visible-light spectrum of the satellite opened up to an abundance of clouds over the state, with a beautiful top-down perspective of massive thunderstorm over the Big Bend National Park, and a smaller, but equally as intense thunderstorm near Corpus-Christi.
What's in store today for the Del Rio area? Great Question!
Forecasting geniuses have been rather stumped over the last week or so about severe weather through the Rio Grande Plains. While atmospheric dynamics would certainly support severe weather - the atmosphere has under-performed substantially.
Yesterday was the first day that any confirmed severe weather was actually observed through the region - and that particular storm dropped some large hail near the small town of Knippa - just east of Uvalde. A storm late in the afternoon on Friday also raised some concern, but stayed on the Coahuila side of the Rio and went unconfirmed.
Another clue that I observed today with the weather balloon data indicated ample wind shear from the ground level to toe stratosphere. This is also conducive to thunderstorm growth because it has the ability to sustain storms by separating the updraft of moisture from the downdraft of rainfall, This allows storms to continue to "feed" with moisture rather than rain themselves out.
Lastly, what I observed the amount of moisture through the atmosphere - known as Precipitable Water. Today - the atmosphere over Del Rio is near it's maximum value for this time of year in regards to moisture content. In other words - there's a lot of moisture aloft over the region that could, under the right conditions, initiate some localized flooding.
- Meteorologist Dan Schreiber
After getting pelted during early evening with pockets of large hail, portions of the City of Del Rio and Eastern Val Verde County endured a second round of storms late in the evening on May 10th, 2017. A confirmed tornado was reported by Laughlin AFB weather personnel just north of the base in a rural part of far-southeastern Val Verde County.
Shortly after crossing the Rio Grande from near Ciudad Acuña, Coahuila, Mexico, what appeared to be an insignificant thunderstorm erupted into a tornadic state just west of the Del Rio International Airport, triggering a National Weather Service-Issued Tornado Warning at 10:35 PM.
The thunderstorm began to gain momentum shortly after crossing the Rio Grande River, similar to a previous storm just hours before, and displayed easily-identifiable radar-indicated hail (pink, in the base reflectivity image above). While this storm did not look to produce very large hail - immediate concern was drawn to the tornadic vortex signature (upside-down triangle) found near the hook (inflow) of the supercell thunderstorm.
While this signature can often be mis-interpreted by weather radars - a quick look at inbound-vs-outbound velocities (shown in the image to the right above as green = inbound and red = outbound) verifies decently strong rotation in the storm (and was further verified with elevated radar scans).
This was enough to warrant a tornado warning, which accompanied the storm across much of the northern half of the city and into more rural ranch land north of Laughlin AFB into Kinney County.
While at the time of this writing there has not yet been any reports of damage or injury from this storm, a wall cloud and a brief tornado were visually observed roughly four miles from the airfield northwest of Laughlin AFB shortly after these radar images were taken.
While these storms didn't look all too impressive on reflectivity images - they were moving fast, and dumping a good deal of rainfall. In fact, 2.14 inches of rain was recorded at San Antonio International Airport, and several wind gusts through the area were reported to be over 60 miles per hour - and a few reports of hail were also documented.
Dan Schreiber is an operational meteorologist, with experience