Record Total Precipitable Water in Alaska

August 14th, 2019 |

Plot of rawinsonde data from Anchorage, Alaska [click to enlarge]

Plot of rawinsonde data from Anchorage, Alaska [click to enlarge]

Plot of rawinsonde data from Fairbanks, Alaska [click to enlarge]

Plot of rawinsonde data from Fairbanks, Alaska [click to enlarge]

Total Precipitable Water (TPW) calculated from rawinsonde data at both Anchorage and Fairbanks, Alaska were all-time record maximum values at 00 UTC on 14 August 2019.

The microwave-based MIMIC TPW product (below) showed an atmospheric river of moisture moving northeastward toward Alaska during the 2 days leading up to the record-setting TPW values on the Anchorage and Fairbanks soundings. The global view suggested that some of this moisture may have originated from the northern periphery of the TPW reservoir associated with slow-moving Typhoon Krosa in the West Pacific Ocean, being transported eastward then northeastward by a series of frontal waves (surface analyses).

MIMIC Total Precipitable Water [click to play animation | MP4]

MIMIC Total Precipitable Water [click to play animation | MP4]

MIMIC Total Precipitable Water [click to play animation | MP4]

MIMIC Total Precipitable Water [click to play animation | MP4]

 

Record 24-hour rainfall in Nome, Alaska

August 3rd, 2019 |

MIMIC Total Precipitable Water product [click to play animation | MP4]

MIMIC Total Precipitable Water product [click to play animation | MP4]

The MIMIC Total Precipitable Water (TPW) product (above) showed a northward-moving atmospheric river that was responsible for producing a record 24-hour rainfall amount of 2.47 inches (62.7 mm) ending at 10 pm AKDT on 02 August (06 UTC on 03 August 2019). Some of the poleward transport of moisture was aided by the approach of a Gale Force low (surface analyses).

Blended TPW values reached 2.7 inches near Nome at 1537 UTC on 02 August — and broad areas of TPW greater than 200% of normal (yellow) were seen across the Bering Sea as the atmospheric river approached the Seward Peninsula (below).

Blended Total Precipitable Water and Percent of Normal [click to play animation | MP4]

Blended Total Precipitable Water and Percent of Normal TPW [click to play animation | MP4]

In a plot of surface data from Nome, Alaska over the 02-03 August period (below), heavy rain was reported at 1222 UTC on 02 August.

Time series of surface data from Nome, Alaska [click to enlarge]

Time series of surface data from Nome, Alaska [click to enlarge]

A plot of rawinsonde data from Nome at 12 UTC on 02 August (below) revealed a TPW value of 37.7 mm (1.48 inches), which is among the top 10 TPW amounts on record for that site.

Plot of rawinsonde data from Nome at 12 UTC on 02 August [click to enlarge]

Plot of rawinsonde data from Nome at 12 UTC on 02 August [click to enlarge]

Hurricane Barbara in the East Pacific

July 2nd, 2019 |

GOES-17

GOES-17 “Red” Visible (0.64 µm, top) and “Clean” Infrared Window (10.3 µm, bottom) images [click to play animation | MP4]

1-minute Mesoscale Domain Sector GOES-17 (GOES-West) “Red” Visible (0.64 µm) and “Clean” Infrared Window (10.3 µm) images (above) showed the eye of Category 4 Hurricane Barbara on 02 July 2019. Mesovortices were briefly seen within the eye in the Visible imagery. Barbara was moving through an environment of low deep-layer wind shear and over warm water, factors favorable for rapid intensification (ADT | SATCON).

DMSP-17 SSMIS Microwave (85 GHz) imagery from the CIMSS Tropical Cyclones site (below) showed a closed eyewall at 1448 UTC.

DMSP-17 SSMIS Microwave (85 GHz) image [click to enlarge]

DMSP-17 SSMIS Microwave (85 GHz) image [click to enlarge]

A 1700 UTC  GOES-17 “Red” Visible image with an overlay of Metop-A ASCAT winds (below) revealed surface scatterometer wind speeds as high as 76 knots just north of the eye.

GOES-17

GOES-17 “Red” Visible (0.64 µm) and Metop-A ASCAT winds [click to enlarge]

===== 03 July Update =====

GOES-17 "Red" Visible (0.64 µm, top) and "Clean" Infrared Window (10.3 µm, bottom) images [click to play animation | MP4]

GOES-17 “Red” Visible (0.64 µm, top) and “Clean” Infrared Window (10.3 µm, bottom) images [click to play animation | MP4]

Barbara maintained Category 4 intensity on 03 July — and 1-minute GOES-17 Visible and Infrared GOES-17 images (above) provided a better view of mesovortices within the eye.

Cyclone Fani makes landfall in India

May 3rd, 2019 |

EUMETSAT-8 Meteosat-8 Infrared Window (10.8 µm) umages [click to play animation | MP4]

EUMETSAT Meteosat-8 Infrared Window (10.8 µm) images [click to play animation | MP4]

EUMETSAT Meteosat-8 Infrared Window (10.8 µm) images (above) showed the intensification of Cyclone Fani to a high-end Category 4 storm on 02 May 2019 (ADT | SATCON | PGTW advisory), before eventually making landfall in northeastern India at 0230 UTC on 03 May. During its life cycle, Fani moved over warm sea surface temperature values of 29-30ºC — and deep-layer wind shear of only 5-10 knots on 02 May provided an environment favorable for rapid intensification.

Once inland, Fani was in the process of rapidly weakening to a Category 1 storm as it passed over Bhabaneswar (VEBS), and surface wind gusts to 75 knots were reported at that site (below).

Time series plot of surface observations from Bhabaneswar, India [click to enlarge]

Time series plot of surface observations from Bhabaneswar, India [click to enlarge]

A sequence of VIIRS Infrared Window (11.45 µm) images from NOAA-20 and Suomi NPP as viewed using RealEarth (below) showed snapshots of Fani from 19 UTC on 01 May (over the Bay of Bengal) to 07 UTC on 03 May (after landfall).

Sequence of NOAA-20 and Suomi NPP VIIRS Infrared Window (11.45 µm) images [click to enlarge]

Sequence of NOAA-20 and Suomi NPP VIIRS Infrared Window (11.45 µm) images [click to enlarge]

A comparison of VIIRS True Color Red-Green-Blue (RGB) and Infrared Window (11.45 µm) images from NOAA-20 and Suomi NPP on 02 May (below) showed Fani shortly after it had reached Category 4 intensity.

VIIRS True Color RGB and Infrared Window (11.45 µm) images from NOAA-20 and Suomi NPP [click to enlarge]

VIIRS True Color RGB and Infrared Window (11.45 µm) images from NOAA-20 and Suomi NPP [click to enlarge]

DMSP-17 SSMIS Microwave (85 GHz) image at 1230 UTC + Meteosat-8 Infrared Window (10.8 µm) image at 1300 UTC [click to enlarge]

DMSP-17 SSMIS Microwave (85 GHz) image at 1230 UTC + Meteosat-8 Infrared Window (10.8 µm) image at 1300 UTC [click to enlarge]

A toggle between a DMSP-17 SSMIS Microwave image at 1230 UTC and a Meteosat-8 Infrared Window image at 1300 UTC  from the CIMSS Tropical Cyclones site (above) showed the eye and totally closed eyewall of Fani when it was at its peak intensity on 02 May. However, the MIMIC TC product (below) indicated that the eastern portion of the eyewall started to erode as Fani approached the coast and began to undergo an eyewall replacement cycle.

MIMIC TC morphed microwave product, 01-02 May [click to enlarge]

MIMIC TC morphed microwave product, 01-02 May [click to enlarge]

On 30 April, VIIRS DayNight Band (0.7 µm) images (below, courtesy of William Straka, CIMSS) revealed widespread mesospheric airglow waves (reference) within the western semicircle of the storm, along with numerous bright lightning streaks associated with convection south of the storm center.

Suomi NPP VIIRS Day/Night Band (0.7 µm) and Infrared Window (11.45 µm) images at 1939 UTC on 30 April [click to enlarge]

Suomi NPP VIIRS Day/Night Band (0.7 µm) and Infrared Window (11.45 µm) images at 1939 UTC on 30 April [click to enlarge]

NOAA-20 VIIRS Day/Night Band (0.7 µm) and Infrared Window (11.45 µm) images at 2029 UTC on 30 April [click to enlarge]

NOAA-20 VIIRS Day/Night Band (0.7 µm) and Infrared Window (11.45 µm) images at 2029 UTC on 30 April [click to enlarge]