Subtropical Storm Alex (NHC advisory archive) formed in the far eastern Atlantic Ocean on 13 January 2016. Animations of GOES-13 (GOES-East) 0.63 µm Visible (above) and 10.7 µm Infrared images (below) showed the initial evolution and northeastward motion of the storm. Alex is only the 4th known January tropical or subtropical storm to have formed in the Atlantic since the historical record began in 1851.

===== 14 January Update =====

A comparison of Suomi NPP VIIRS Infrared (11.45 µm) and Day/Night Band (0.7 µm) images at 0320 UTC (below) showed the well-defined eye of Alex. With the Moon in the Waxing Crescent phase (at 30% of Full) there was enough illumination to demonstrate the “visible image at night” capability of the Day/Night Band. A magnified version of the Infrared image showing the eye can be seen here.

As of 15 UTC on 14 January, Alex had made the transition from subtropical storm to Category 1 hurricane (eastern Atlantic Ocean surface analyses). GOES-13 Infrared (10.7 µm) images (below) showed the well-defined eye that had formed. Alex became the first known January hurricane to form in the Atlantic Ocean since 1938, and only the second hurricane on record to from north of 30ºN latitude and east of 30ºW longitude.

A DMSP-16 SSMIS Microwave (85 GHz) image (below) revealed the eye structure at 1653 UTC.

===== 15 January Update =====

While still classified as a hurricane, Alex was undergoing a weakening trend as it approached the Azores Islands during the morning hours on 15 January. GOES-13 Infrared (10.7 µm) images (below) showed a strong convective band that produced a brief period of heavy rain at Ponta Delgata and Lajes Acores several hours prior to the passage of the eye of Alex (which occurred during the 11-14 UTC time frame — and Alex was downgraded to a Tropical Storm as it made landfall at 1315 UTC). At Ponta Delgata a peak wind gust of 50 knots was recorded at 1130 UTC.

ISS-Rapidscat surface scatterometer winds (below) showed the center of circulation of Alex just south of the Azores Islands at 1118 UTC.

===== 16 January Update =====

Using a long animation of GOES-13 Water Vapor (6.5 µm) images covering the 06-16 January period (below; also available as a large 165-Mbyte animated gif), the origination of Hurricane Alex could be traced back to a strong baroclinic mid-latitude cyclone that rapidly intensified off the southeast coast of the US on 07 January.

The origin and motion of Alex could also be identified using the satellite-derived atmospheric motion vector 850 hPa Relative Vorticity product (below). A region of lower-tropospheric vorticity over Cuba on 06 January began moving northeastward across the Bahamas, then eastward across the Atlantic Ocean on 07 January.

For another perspective on the history of the development of Alex, see this article from The Weather Channel.

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Tropical Storm Pali has formed in the central Pacific, in a region east-southeast of Kwajalein Atoll (which atoll is at 9 N, 168 E), just west of warm Sea Surface Temperature anomalies (Source) associated with the ongoing El Nino. For the Central Pacific basin, Pali set new records for being the earliest-forming tropical cyclone on record (21 UTC on 7 January), as well as the most Equatorward-forming (at 4.7º N). The Himawari animation, above, of the 6.2 µm Water Vapor imagery from 0000 UTC on 7 January through 1500 UTC 8 January 2016 (mp4 available here), shows impressive upper-level outflow from the region of convection surrounding the storm center. A longer animation of Himawari 10.4 µm Infrared imagery (from 0000 UTC 06 January to 0650 UTC on 8 January) is available here. The Composite Infrared Imagery from AWIPS II, below, shows the slow but steady organization of the storm. Infrared brightness temperatures are very cold, with temperatures occasionally colder than -95º C.

Pali is forming in a region that allows views from both GOES-15 (overhead at the Equator and 135º W) and Himawari-8 (overhead at the Equator and 140º E). The Infrared animation below shows GOES-15 at Full Resolution from the Full Disk Imagery that is used to view Pali. Note that Himawari data has been degraded both spatially and temporally in the animation (to match that of GOES).

An animation that is at full resolution for Himawari-8, for just 3 hours, from 0600-0900 UTC, is below. Only two GOES-15 Images are available during this time period that includes 19 Himawari-8 images. (Note also the increase in spatial resolution with Himawari, from 4 km for GOES to 2 km for Himawari) There is considerable evolution to the storm during these three hours that present-day GOES cannot view because of limited scanning capabilities. GOES-R will provide spatial resolution and image scan rates identical to Himawari-8 so meteorologists will be better able to monitor storm evolution.

Himawari True-Color Imagery, below, shows both Pali, a large relatively disorganized system in the central north Pacific and Cyclone Ula, a compact and more organized system in the tropical south Pacific. Himawari True-Color (actually a 4-banded composite meant to emulate True Color) imagery is routinely available here.

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Water Vapor Imagery, above, from GOES-15, shows a parade of storms that have hit California (now over the intermountain West and the Plains), are hitting California, or will hit California. MIMIC Total Precipitable Water, below, shows the the ribbons of moisture associated with each storm. The storm hitting California on 6 January appears not to access as much moisture as previous systems (although rainfall will still be heavy as the forcing is strong). However, the cellular structures in the water vapor imagery (above) suggest very cold air aloft that will support the development of showers on 7 January. In addition, moisture is pooling north of Hawaii in this animation and that moisture may be drawn into California by the end of the week. Click for an animated gif (100+ Megabytes) (mp4) of the GOES-15 Water Vapor Imagery from 1-7 January, showing the progression of storms into California.

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As a Low pressure center moved away from the coast, and a High pressure system approached from the west (link), cold air swept south along the east coast of the United States and produced light snow/flurries over Tidewater Virginia and the Outer Banks of North Carolina on Tuesday, 5 January 2016. The animation above, of the GOES-13 Visible Imagery, shows a band of cloudiness originating over the northern Chesapeake Bay that widened as it moved south. By the time it reached southern Virginia, it was producing snow. Conditions over the Outer Banks of North Carolina were very icy, as shown in this Video, courtesy of Sam Walker. The snow closed schools in Dare County. The 1300 UTC observations, below, in a toggle with 2100 UTC observations, showed morning snow over the Tidewater region and over extreme eastern North Carolina with strong north-northwest winds (gusting to 30 knots at Norfolk Naval Air Station). By 2100 UTC, winds had shifted and weakened and snow was no longer reported (an intermediate 1754 UTC MODIS image showed the cloud bands 1 hour after reports of snow had ended). It was still cold however: the sub-freezing daytime high in Norfolk VA was the first of the winter and the coldest day since late February 2015 (Temperatures did rise above freezing after sunset, however, to 35 at 11:59 PM on the 5th).

The cold air aloft necessary for Bay Effect (or Ocean Effect) snows was present in the 1200 UTC Sounding at Wallops Island, Virginia (or click to compare Stuve and Skew-T plots from this site). Temperatures 1 km above the surface were at -15.7ºC, with 850-mb temperatures near -10ºC. NOAA’s NAM and GFS Numerical Models indicated 850-mb temperatures cooler than -10ºC near Chesapeake Bay. That cold air in combination with warm sea-surface temperatures at or above +10ºC, at least as forecast (source) or as recently observed from satellite (AVHRR: 30 December and 27 December) [source], and MODIS: 02 January) or observed from buoys, easily met the 13ºC temperature difference threshold commonly cited to support lake effect snows.

In the preceding nighttime hours before visible imagery was available, long and well-defined bay effect and ocean effect cloud bands were evident on 1-km resolution Terra and Aqua MODIS 11.0-3.7 µm IR brightness temperature difference (legacy “fog/stratus product”) images, below. One cloud band was slowly moving westward over time toward the Outer Banks of North Carolina; at 07 UTC, Kill Devil Hills (located just north of Manteo, station identifier KMQI on the images) was reporting moderate snow reducing the surface visibility to 1/2 mile.

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