Hurricane Andres (above) in the eastern tropical Pacific was on 2 June 2015 joined by Tropical Storm Blanca (below). Blanca was forecast to become a Hurricane later on 2 June as Andres weakens. The circulation of Andres, above, is well-established, with good anti-cyclonic outflow and curved inflow bands. Shear values are low. (Graphics come from this site). However, Andres has moved over relatively cool Sea Surface Temperatures that spell weakening.

Blanca, in contrast, has a circulation that is not so well-defined. However, the storm is over very warm water, and also in a region of relatively low shear. Strengthening is forecast.

The animation of Andres at top shows a ragged appearance as dry air intrudes upon the circulation from the south and west. This dry air is apparent in the MIMIC Total Precipitable Water animation below. The circulation of Blanca appears at the end of the animation, embedded within a rich source of tropical moisture.

Sea-surface temperatures off the Pacific Coast of Mexico have been warmer than normal for much of this year (Map, data from here). Warmer-than-normal sea-surface temperatures argue for stronger hurricanes, and Andres was a Category 4 storm on 1 June with a well-developed eye. Andres is one of only 5 May storms in the eastern Pacific since 1970 to achieve Major Hurricane status (Link).

Aqua overflew Andres shortly before 1800 UTC on 1 June, and the water vapor imagery of the storm at that time is here. The True-Color imagery is shown below.

A storm-centered animation over Andres’ lifecycle is shown below. The storm starts in the moisture-rich ITCZ and ends as an isolated region of moisture surrounded by dryness.

For further information on these storms, consult the National Hurricane Center website.

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Historically heavy rains fell over the southern Plains in May of 2015, with numerous stations setting record monthly rainfall marks. For example, Oklahoma City reported 19.48″ of rain in May 2015; the previous record wet month was 14.66″, set in June 1989 (14.52″ of rain fell in May 2013). The three-hourly water vapor imagery, above (Click here for mp4 file; the animated gif above exceeds 90 M), from GOES-13 shows repeated thunderstorm development over western OK and western Texas that subsequently moved east. Persistent southwesterly flow is also apparent. In comparison, three-hourly water vapor imagery from GOES-13 for May 2014, below (Click here for mp4 file), shows less frequent convection and more northwesterly flow. Widespread convection is much less frequent over the Plains in May 2014 (a month that saw 4.44″ of rain fall in Oklahoma City).

The mean 6.5 channel GOES-13 Brightness Temperature for May 2015 was more than 2 degrees cooler than in May 2014 (237.2 K in 2015 vs. 239.6 K in 2014). It should not be surprising that the top of the moist layer in 2015 was higher (cooler) than in 2014.

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The Kuchinoerabu-jima volcano in Japan experienced a violent eruption beginning around 00:59 UTC on 29 May 2015 — the expanding volcanic cloud was captured by 0.5-km resolution Himawari-8 AHI 0.64 µm visible channel images (above; click image to play animation; also available as an MP4 movie file). A mid-layer volcanic cloud was seen moving to the west-northwest, while a high-altitude plume spread out as it moved east-southeastward.

About an hour after the eruption, Terra MODIS products at 0205 UTC from the SSEC Volcanic Cloud Monitoring site are shown below. Retrieved volcanic Ash Probabilities were very high for both cloud segments; for the southeastern cloud segment, the maximum volcanic Ash Height was in the 10-12 km range, volcanic Ash Loading was high, and the largest Ash Effective Radius values were in the 8-10 um range.

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A tornado was reported near Yuma, CO, (SPC Storm Reports) at 1910 UTC on 27 May 2015. GOES-14 was in SRSO-R scanning mode, and a storm-centered animation of the visible imagery (0.626 µm) is shown above (Warning: the animation above is 270M; click here for an mp4, or view it on YouTube). Note that GOES-14 produces no imagery from 1900-1915 UTC when the satellite is performing daily station-keeping maneuvers. The tornado occurred early in the life of the supercell on which the animation centers.

The NOAA/CIMSS ProbSevere output for this storm is shown below. ProbSevere increased above 50% at 1904 UTC. The satellite information for the storm object was derived from GOES-13 data between 1730 and 1745 UTC, when strong growth occurred, and from 1745-1815 UTC when weak glaciation occurred (how the reduced time resolution at that time, when GOES-13 is scanning a full-disk image, affected the Glaciation estimates is not certain — ‘weak’ is probably a lower bound).

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