technology, weather

Rain temporarily leaves Southwest Florida (H. Michael Mogil, CCM, CBM, NWA-DS*)

The focus during tropical cyclone events is typically on high winds, coastal storm surge, heavy coastal and inland rainfall, and possible flooding. However, if one is located far enough away from the storm’s circulation, atmospheric processes may lead to less rainfall. Such is the case for southwest Florida during the past few days. And while rainfall didn’t vanish entirely from the southwest Florida area, it certainly dropped off dramatically.

Fig. 1 shows the upper level wind flow as determined by weather satellite and radiosonde (weather balloon) data. Computer programs can track cloud elements and compute their motion (and, hence, winds). Combining radiosonde wind and temperature data and infrared satellite cloud temperature measurements, computer programs can assign winds into specific altitude bands.

Late on Jun. 21, 2017, it is easy to see this altitudinal variation near Tropical Storm Cindy (located just offshore from the Texas-Louisiana coast). Winds shown in green show a counterclockwise (low-pressure) circulation. Mid-altitude winds are tagged to be between 20,000 feet to 25,000 feet above ground level or at pressure altitudes of 350mb to 500mb. Pressure is measured in millibars (mb) and decreases as one goes higher in the atmosphere (due to less air above).

To the north and east of Cindy’s mid-altitude circulation, higher altitude winds (shown in blue) actually spin slightly clockwise (indicating a high-pressure system). This differential circulation pattern is often found in well-developed tropical storms and hurricanes.

This upper-level circulation leads to a ridge or high-pressure system to the east of the storm’s circulation. In this high-pressure system, sinking air dominates. This is in contrast to the rising air motion (and associated clouds and precipitation) within Cindy’s circulation. Note that precipitation can still extend quite a distance from the storm’s center, but is mostly confined within the low- and mid-level counter-clockwise circulation pattern (Fig. 2). As a result of these upper and lower level circulation considerations, southwest Florida experienced less cloudiness and less shower and thunderstorm activity during the past two days.

As Cindy landfalls, weakens and moves to the northeast (see Fig. 2 – the elongated shape of the storm’s circulation is oriented in the direction of future movement), the upper ridge over Florida will slowly weaken and a more usual daytime shower and thunderstorm pattern will return to southwest Florida.

© 2017 H. Michael Mogil

Originally posted 6/22/17

* The National Weather Association Digital Seal (NWA-DS) is awarded to individuals who pass stringent meteorological testing and evaluation of written weather content. H. Michael Mogil was awarded the second such seal and is a strong advocate for its use by weather bloggers.

technology, weather

Tornado watchers from the sky

Last November, a new weather satellite (GOES-R*), was launched from the Kennedy Space Center in Florida (Fig. 1). This new space dweller is equipped with modern and powerful instruments, opening numerous possibilities for improved weather analysis and forecasting.

Today, I would like to focus on a brand-new instrument – The Geostationary Lightning Mapper (GLM). Scientists believe that this could be the key to improved tornado forecasting.  Studies have shown that there is a positive relationship between changes in the lightning pattern inside a storm and the formation of a tornado. But, before we get into that, let’s talk about thunderstorm formation, particularly that of tornadic thunderstorms.

In areas with vertical differences in wind direction and speed (what meteorologists call wind shear), there is a potential for the formation of horizontal rolls (Fig. 2).

When a powerful thunderstorm develops, the lifting air associated with it tilts these rolls, turning them into more vertical positions (one with rising air and one with sinking air) as shown in Fig. 3.

Under some circumstances, the upward rotation can extend to the ground generating a violent column of rotating air, known as a tornado. Unfortunately, there are still limitations to pin-pointing the onset or potential onset of tornado formation (i.e., the warning process). Severe weather forecasters typically recognize the larger-scale conditions and general geographic areas in which tornadoes can possibly form (watch process).

Once a watch is issued (or localized conditions suggest possible tornado or severe weather development), storm spotters and Doppler radar become the key tools available to local National Weather Service forecasters. Trained spotters can recognize cloud features that suggest possible severe weather. Radar, however, can probe the interior of the thunderstorms. Determining the presence of certain echoes (radar patterns based on the size and distribution of water droplets) can indicate the presence of a rotating core that is often linked to the occurrence of tornadoes.  Doppler radars are also capable of detecting areas of rotation (based on the wind movement toward/away from the radar).  Still, radars have limitations regarding vertical and horizontal coverage and resolution. At large distances, the radar may even “overshoot” the tornadic circulation, passing high above it. So, depending on the distance from the storm to the radar and other factors, forecasters may not be able to detect a tornadic signature.

Recent research indicates there is a close relationship between lightning and tornado formation. A considerable and sudden increase in lightning flash rates (lightning frequency), known as a “jump,” has been observed to take place just before tornado formation. These jumps have been registered 20-25 minutes before the tornado occurs (i.e., about 10 minutes more than the current average tornado warning lead-time). Until now, the only possible way to measure the lightning activity inside the storms, was to use the National Lightning Detection Network, which was the most accurate way to record time, strength and number of strokes of cloud to ground lightning flashes. But, the more intense and severe the storm is, the more important the intra-cloud lightning (cloud to cloud strokes) may be.

That is why the meteorological world is celebrating the launch of GOES 16. This satellite is opening new ways to make huge advancements in weather observing, analysis and forecasting. With the arrival of the GLM, the satellite is capable of detecting intra-cloud, cloud-to-ground and cloud-to-air lightning.

With the 2017 tornado season well underway, scientists have already been looking at GLM’s capabilities and reliability in detecting tornadoes.

*The name of the satellite was changed from GOES R to GOES 16, once the spacecraft reached its stationary orbit on November 29th.

© 2017 Mayguen Ojeda

Originally posted 6/14/17

observations, technology, weather

GOES-R launch imminent (H. Michael Mogil, CCM, CBM, DMS)

fig001-countdown-clock-kscEarly in the Obama Administration, the space program, as we knew it at the time, took a hit. Instead of a continued emphasis on manned space travel, the focus was shifted to science, including climate. The Constellation program was terminated and NASA continued contracts with Space Exploration Technologies (SpaceX) and Orbital Sciences Corporation to deliver cargo to the space station. SpaceX and other firms were also developing spaceships that could carry passengers to orbit and back.

NOAA’s satellite program was caught in the crosshairs of the resulting contentious budget cutting process. And then came Hurricane Sandy (2012) and NOAA’s funds for the GOES R – GOES U program were restored.

fig002-atlas-v-launch-padThe result was that the once government-driven space program became even more of a government-private sector program. Tough to swallow at the time, locals in the greater Cape Canaveral area hung in there. Now, with President-elect Trump on center stage, the Space Coast may be rewarded for its patience.

Today, Nov. 19, 2016 is, “one small step” in the process. The first in a new series of advanced weather satellites should be launched into geosynchronous (earth-

fig003-atlas-v-on-launch-pad-close-upbased) orbit, around 5:42 p.m. E.S.T. If successful, the GOES-R satellite will go into a holding orbit initially; then, it will, through a series of maneuvers during the next few weeks, be placed in orbit some 22,000 miles above the Earth’s surface by early Dec. 2016. As the Earth spins once a day, the satellite will orbit once a day. This will keep a fixed Earth point beneath the satellite. The result will be a capability to view the Earth as though the Earth was not moving. Animated image sequences and an incredible array of data fields covering a fixed area will continue to be available online and on air. The satellite will also provide new and improved views of “space weather,” including sunspots, solar flares and the solar wind. Following testing and validation, the satellite should start providing fully operational data by next summer.

fig004-radisson-hotel-cocoa-beachThe other day, the NASA countdown clock (Fig. 1) showed how close we were to the GOES-R launch. Yesterday, several dozen TV meteorologists and NOAA and NASA officials watched as the Atlas-V rocket was rolled out to Launch Pad 41 (Fig. 2 and Fig. 3). The TV meteorologists filmed, blogged and posted about the rollout.  The day became quite long as, after lunch, the TV broadcasters attended a more than six-hour GOES-R training program in which information was shared about new satellite capabilities.

But on the streets, people were abuzz about the launch. NASA is estimating that some 15,000 people will be watching from nearby vantage points. At least one hotel (Fig. 4) boldly pronounced how it felt about the launch.

As I put down my computer-based “pen,” just moments ago, the countdown clock read T minus six hours three minutes and 22 seconds and counting…

© 2016 H. Michael Mogil

Originally posted 11/19/16

observations, technology, weather

GOES-R is coming (H. Michael Mogil, CCM, CBM, DMS)

NOTE: This is the first of a series I will be writing this week about GOES satellites, specifically the launch of GOES-R. I’m on assignment at the Kennedy Space Center attending a four-day satellite workshop and will be here on Sat., Nov. 19, 2016 to view the launch. As of late Wed., Nov. 16, 2016, Air Force weather forecasters (who provide launch support 365-24-7) have indicated a 90 percent chance of favorable weather conditions at launch time.

fig001-tiros-image-from-1960On Apr. 1, 1960,  a polar orbiting satelliteTIROS-I (Television InfraRed Observation Satellite), transmitted its first image. The image showed clouds across parts of New England and the Canadian Maritimes (Fig. 1). To say that the image was “fuzzy,” would be an understatement. To say that this satellite (and others launched by both the U.S. and other nations in the 1960’s) began a journey in which weather satellites became an integral part of the global weather forecasting system.

fig002-goes-rNow, five and a half decades later, the sixteenth in a series of Geostationary Operational Environmental Satellites (GOES) – GOES-R (Fig. 2) – is ready to move toward center stage (tentative launch date is this coming Saturday, Nov. 19, 2016 within a launch window from 5:42 p.m. E.S.T to 6:42 p.m. E.S.T.). From the initial GOES A-C series, launched in the 1974-1978 time window, satellite sensors, operational requirements and data transmitting and processing advances (among other things) have evolved to a point that GOES-R is going to be providing unparalleled data gathering for Earth, space and Sun forecasting and research.

Geostationary means that the satellite, positioned some 22,000 miles above a point on the Equator, moves fast enough to remain in position above that fixed point. As a result, the satellite does not see a moving Earth, but rather a stationary one. This is the reason that we get to see satellite clouds and water vapor imagery in motion.

The Advanced Baseline Imager – ABI (just one of several instrument packages onboard – Fig. 2) – will view the Earth with 16 different spectral bands (compared to five on the current GOES). Of the 16 bands, there will be two visible channels, four near-infrared channels, and ten infrared channels.

GOES-R will provide three times more spectral information, four times the spatial resolution, and more than five times faster temporal coverage than the current GOES satellites.

fig003-goes-operational-areasThese satellites will provide continuous multi-spectral imaging and atmospheric measurements of Earth’s Western Hemisphere, total lightning mapping, and space weather monitoring (Fig. 3).

Simply stated, the GOES-R series, will be a game changer on many fronts.

According to the GOES-R program brochure, “The GOES-R Series Program is a collaborative effort between NOAA and NASA to develop, deploy and operate the satellites. The GOES-R series is a four-satellite program (GOES-R, S, T and U) that will extend the availability of the operational GOES satellite system through 2036…”

© 2016 H. Michael Mogil

Originally posted 11/17/16