The third named storm of the Eastern Pacific tropical season has formed. (Click here for NHC‘s public advisory on the naming of Calvin) The mp4 animation above (click here for an animated gif) shows the evolution of the system for the 24 hours ending at 1210 UTC on 12 July as it gradually acquired rotation, evolving from a large convective complex at the start of the animation while it traveled over very warm waters.

1-minute Mesoscale Domain Sector GOES-18 Infrared and Visible images (above) showed the period from 0900-1500 UTC (1315-1500 UTC for the Visible imagery), as Tropical Depression Three-E intensified along the Monsoon Trough to become Tropical Storm Calvin. A few convective bursts were evident near the storm center, with overshooting tops exhibiting infrared brightness temperatures as cold as -86ºC at 1441 UTC.

Calvin is now in a favorable environment for strengthening. The toggle below (using imagery from this website) shows the forecast path, the sea-surface temperatures, and the diagnosed atmospheric shear.

Abundant moisture surrounding Calvin is depicted in the MIMIC Total Precipitable Water animation shown below. The circulation of Calvin is apparent just west of 110^oW Longitude.

Atmospheric steering flow, shown below as the 850-500mb mean layer wind, takes the system on a westerly course. Long-range forecasts have the system (or its remnant moisture) affecting the Hawai’ian islands in the middle of next week. The movement and evolution of anticyclones to the northeast and northwest of Hawai’i shown below will be steering Calvin as that happens.

 

For the latest on Calvin, refer to the webpages of the National Hurricane Center.

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Vermont was hit with its worst flooding in over a century, making it one of the worst natural disasters in the state’s history. Rains dumped up to nine inches from Monday, July 9 and into Tuesday, July 10, 2023. Major roads and highways were shut down, and more than 200 rescues were carried out.

Sentinel 2A, a polar-orbiting satellite operated by the European Space Agency, captured imagery of this flooding. CIMSS scientist Sam Batzli made this data accessible on RealEarth, seen in the image below.

CIMSS scientist Danielle Losos created a Normalized Burn Ratio over the Sentinel 2A imagery and produced some interesting results. It turns out that burn scars and water both reflect differently than the surrounding landscape, so flooding shows up in a Normalized Burn Ratio. Two examples can be seen below.

You can explore the Normalized Burn Ratio over parts of Vermont for these dates using RealEarth. As of Thursday, July 13, Vermont may be due for more rain, and a new flood watch may be put into place by Thursday afternoon.

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GOES-16 (GOES-East) Day Land Cloud Fire RGB, Shortwave Infrared (3.9 µm), “Red” Visible (0.64 µm) with an overlay of the Fire Temperature derived product and Visible images with an overlay of the Fire Power derived product — both derived products being components of the GOES Fire Detection and Characterization Algorithm FDCA — (above) showed thermal signatures associated with the Pallet Fire near Coloma in central Wisconsin on 10 July 2023. Wind gusts at the nearby Wautoma Airport reached 23 knots — and the smoke plume briefly reduced surface visibility at that site to 5 miles at 23 UTC.

Cursor-sampling at 2126 UTC (below) indicated that the warmest 3.9 µm brightness temperature was 108.82ºC, with a peak Fire Power value of 1524.24 MW.

GOES-16 True Color RGB images from the CSPP GeoSphere site (below) highlighted the distinct smoke plume created by this wildfire.

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GOES-16 Visible (Band 2, 0.64 µm) and Infrared (Band 13, 10.3 µm) imagery at 2316 UTC on 9 July 2023, above, show cloud-top features commonly associated with intense convection off the east coast of Florida, to the southeast of Cape Canaveral. RADARSAT-2 overflew this region at the same time, and derived SAR wind estimates, toggled above with the ABI data, exceeded 50 knots (the yellow/red enhancement) with the southern convective cell.

Do you think those SAR wind observations are credible? Sometimes when SAR winds are very strong in regions of convection, the enhanced wind signal occurs because of reflection off ice crystals within the cloud. When that happens, the Normalized Radar Cross Section (NRCS) field will frequently acquire a feathery look. That is not occurring on this day, as shown in the toggle below of derived wind speed and NRCS, at least not in the region of the strong convection just east of the Florida coast. It’s likely that winds over the ocean here were close to 50 knots in strength.

NOAA/CIMSS ProbSevere (version 3) identified the convective cell at 2316 UTC, as shown below. However, probabilities were quite small — less than 10%, albeit with a maximum shortly after 2300 UTC (Click here to see a ProbSevere readout for the Radar Object associated with the southern part of the convection, the one that is oriented north-south). A Special Marine Warning was nevertheless in effect in the region of strong winds. Probabilistic guidance such as ProbSevere should be used in concert with other products to arrive at a warning decision. In this case the other products argued persuasively for warning issuance.

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