Hourly GOES-13 Visible Imagery (click image to play animation)

Carlotta is the third named system, and second Hurricane, of the young eastern Pacific Tropical Season. Hourly imagery from GOES-East shows the increase in organization in the storm as it approaches the coast of Mexico on the morning of June 15 2012. AMSU imagery from Channel 7 at 11UTC on 15 June shows the characteristic warm core usually found in tropical cyclones.

During a period of rapid intensification in the morning, GOES-13 10.7 µm IR channel images (below; click image to play animation) exhibited unusually cold cloud top IR brightness temperature values (as cold as -85 C at 15:45 UTC). This IR temperature was quite a bit colder than the tropical tropopause as indicated on the Acapulco, Mexico rawinsonde data, suggesting a significant degree of overshooting.

GOES-13 10.7 µm IR channel images (click image to play animation)

Data from the Cooperative Institute for Meteorological Satellite Studies’ (CIMSS) Tropical Cyclones site show that Carlotta is in a region that favors intensification. Sea-Surface Temperatures are very warm and shear is (although not weak) modest. Warm surface SSTs do not extend to great depth this early in the season (as shown in this map of Oceanic Heat Content); Carlotta’s forward motion should inhibit any weakening that might arise due to mixing of cooler sub-surface waters, however.

GOES-15/GOES-13 composite of Water Vapor images

Carlotta is embedded within a very moist airmass. GOES water vapor imagery from 1500 UTC on 15 June (above), shows very little dryness near the storm. A MIMIC animation of Total Precipitable Water (TPW), below, shows the rich values of TPW surrounding the storm. As this airmass interacts with the high terrain of central coastal Mexico, life-threatening heavy rains are likely. Note how moisture-rich air associated with the hurricane is approaching the coast of Mexico from the east-southeast as moisture-rich air farther offshore is approaching from the west-southwest.

MIMIC Total Precipitable Water Imagery (click image to play animation)

Morphed Observations of Microwave Imagery

Morphed microwave imagery shows the quick organization of Carlotta for the 24 hours ending mid-day on June 15th. A nearly complete eyewall has developed during this time.

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Radar reflectivity mosaic

A radar reflectivity composite (above) showed a large Mesoscale Convective System (MCS) that was moving across parts of Minnesota and Wisconsin on 14 June 2012, producing heavy rainfall (2.99 inches at Zumbrota in southeastern Minnesota) and some hail (SPC storm reports).

AWIPS images of GOES-13 0.63 µm visible channel data (below; click image to play animation) showed a broad area of anticyclonic cirrus outflow around the southern periphery of the MCS as it was dissipating during the late morning and early afternoon hours. There were a number of pilot reports of moderate turbulence seen within this banded area of cirrus outflow.

GOES-13 0.63 µm visible images with pilot reports of turbulence (click image to play animation)

The banding structure within the cirrus outflow region was clearly shown on a 375-meter resolution (re-mapped onto an AWIPS 1 km grid) Suomi NPP VIIRS 11.45 µm IR image at 18:35 UTC  (below). A comparison with the corresponding 4-km resolution GOES-13 10.7 µm IR image demonstrated the advantage of higher spatial resolution for depicting such features.

Suomi NPP VIIRS 11.45 µm IR image + GOES-13 10.7 µm IR image

The pronounced anticyclonic motion of the cirrus outflow (also verfied using MADIS 1-hour cloud-tracked winds) was creating strong wind shear aloft over much of eastern Iowa, southern Wisconsin, and northern Illinois — note how different the satellite wind vector directions were from the NAM 500-100 hPa deep-layer wind flow streamlines over that region (below). This strong wind shear aloft may have been a factor contributing to the numerous pilot reports of moderate turbulence within the area of cirrus outflow.

VIIRS 11.45 µm IR image + MADIS cloud-tracked wind vectors + NAM deep layer mean wind

A similar depiction of the pronounced wind shear aloft was seen a few hours earlier on a 16:40 UTC MODIS 11.0 µm IR image (below).

MODIS 11.0 µm IR image + MADIS cloud-tracked wind vectors + NAM deep layer mean wind

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Suomi NPP VIIRS 0.64 µm visible and 1.61 µm near-IR images

AWIPS images of Suomi NPP VIIRS 0.64 µm visible channel and 1.61 µm near-IR channel data (above) showed that there was a wide ice-free passage leading from the Bering Sea northward and northeastward through the Chukchi Sea toward Barrow, Alaska (station identifier PABR) on 14 June 2012. On the visible image, ice and optically thick clouds were brighter white, while on the near-IR image ice and water looked very dark (with supercooled water droplet clouds taking on a brighter appearance). Additional information on ice break-up at Barrow is available from the Sea Ice Group at the University of Alaska Fairbanks.

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MODIS and AVHRR Lake Surface Temperatures (click image to play animation)

Clear skies over the upper Midwest on the morning of 13 June 2012 allowed the MODIS instrument on board Aqua and the AVHRR instrument on board NOAA-19 to sense the surface temperature of Lakes Michigan and Superior. Which instrument yielded observations that were closer to those recorded in situ by the moored buoys maintained by the National Data Buoy Center? The loop above of MODIS Lake Surface Temperatures and AVHRR Lake Surface Temperatures suggests that the MODIS-derived values are 1-3 Fahrenheit degrees warmer. MODIS values are also closer to the observed values at the moored buoys (45002 and 45007 in Lake Michigan, 45003 in Lake Huron and 45004 in Lake Superior). The higher spectral resolution on MODIS leads to a more accurate depiction of the lake surface in this case.

The National Weather Service in Sullivan, WI, has noted that lake temperatures are running much warmer than normal this year, in part because of the record warmth in March.

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