1-minute Mesoscale Domain Sector GOES-16 (GOES-East) “Red” Visible (0.64 µm) and “Clean” Infrared Window (10.3 µm) images (above) showed an isolated thunderstorm which produced an EF-1 tornado in northeastern Ohio and 1.0-inch diameter hail in northwestern Pennsylvania during the morning hours on 08 January 2019 (SPC storm reports). (09 January update: a storm survey conducted by NWS Pittsburgh also confirmed an EF-1 tornado with the same storm that earlier produced the 1.0-inch diameter hail)

GOES-16 Mid-level Water Vapor (6.9 µm) images (below) revealed the broad cyclonic flow associated with a trough of low pressure aloft over the Great Lakes, and RAP40 model fields showed an elongated lobe of 500 hPa vorticity pivoting across Ohio and Pennsylvania. After the initial tornado/hail-producing thunderstorms during the late morning hours, a second round of storms produced additional hail in the afternoon.

An EF-1 tornado occurred in Cortland, OH in Trumbull County this morning: https://t.co/VypmgiqrIG pic.twitter.com/p8LQzoXuwN

— NWS Cleveland (@NWSCLE) January 8, 2019

– Today was only the seventh January #tornado of record in Ohio dating to 1950.

– Average high today in nearby Youngstown, OH is 32?.

– Snow is forecast tonight in northeast #OHwx. https://t.co/u0idTHCDZ4

— Jonathan Erdman (@wxjerdman) January 8, 2019

Here’s more info (click link for our PNS) on yesterday’s EF-1 tornado in Mercer County, PA: https://t.co/fCr81lbDxA
It’s not very often that we do tornado surveys in the snow! pic.twitter.com/n7RJLf2HK6

— NWS Pittsburgh (@NWSPittsburgh) January 9, 2019

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* GOES-17 images shown here are preliminary and non-operational *

GOES-17 Low-level (7.3 µm), Mid-level (6.9 µm) and Upper-level (6.2 µm) Water Vapor images (above) showed the intensification of a Hurricane Force low over the East Pacific Ocean on 07 January 2019 (surface analyses).

A comparison of NOAA-20 VIIRS True Color Red-Green-Blue (RGB) and Infrared Window (11.45 µm) images at 2150 UTC as viewed using RealEarth is shown below.

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* GOES-17 images shown here are preliminary and non-operational *

The first official temperature of -50ºF or colder during Alaska’s 2018/2019 winter season was reported by the cooperative observer at Chicken on 06 January — the 24-hour high temperature at that site was -45ºF, with a low of -51ºF (NWS Fairbanks summary). A sequence of Suomi NPP VIIRS Infrared Window (11.45 µm) images (above) showed infrared brightness temperatures as cold as -46.5ªC or -51.7ºF (lighter green enhancement) in the river valleys between Tok and Eagle (Chicken is located about midway between those 2 cities).

A toggle between Infrared Window images from Suomi NPP VIIRS and GOES-17 (below) highlighted the advantage of polar-orbiting imagery at high latitudes — improved spatial resolution and a better viewing angle provides more detailed images. However, it should be noted that the Full Disk GOES-17 imagery that is displayed here using AWIPS is degraded from 2-km to 4-km resolution (at satellite sub-point).

A sequence of NOAA-20 VIIRS Infrared images displayed using RealEarth is shown below. The majority of the scene was cloud-free — except for some cyan-enhanced stratiform clouds moving eastward across parts of the Alaska Range — and although there was some slight diurnal warming seen in the higher terrain, little change was apparent with the signature of colder air (shades of green) that was trapped in the lower elevations and river valleys.

Plots of Fairbanks rawinsonde data from 00 UTC on 06 and 07 January (below) displayed the strong low-level temperature inversion caused by the relatively shallow arctic air.

===== 07 January Update =====

Minimum temperatures of -50ºF and colder were again reported on 07 January, with lows of -56ºF at Chicken and -50ºF at North Pole (NWS Fairbanks summary). 1-minute imagery from a GOES-17 Mesoscale Domain Sector allowed for a more direct full-resolution comparison with Suomi NPP VIIRS imagery — and a toggle between 1926 UTC images (above) revealed significantly greater detail in terms of the cold air confined to river valleys on the VIIRS image. The enhancements used in this comparison have identical temperature ranges for each of the color segments (there are some color vs. temperature offsets with the GOES/VIIRS infrared comparison shown on the previous day). The coldest infrared brightness temperature values on the VIIRS image were -46.4ºC in the vicinity of Tok, Alaska and -49.4ºC across the Canadian border in Yukon — compared to -44.6ºC and -45.1ºC for those two locations on the GOES-17 image.

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A partial solar eclipse occurred on 06 January 2019 (UTC) — and JMA Himawari-8 “Red” Visible (0.64 µm) images (above) showed the shadow moving eastward across parts of Asia and the North Pacific Ocean.

Although it was less obvious, the shadow was also evident on GOES-17 “Red” Visible (0.64 µm) images as it moved across the North Pacific Ocean toward Alaska (below).

* GOES-17 images shown here are preliminary and non-operational *

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