Polar Hyperspectral Modeling for a narrow line of convection

May 13th, 2022 |
PHSnABI 7-h and 1-h forecasts of CAPE valid at 2300 UTC on 13 May 2022 along with GOES-16 Derived CAPE overlaid with GOES-16 Band 13 Infrared (Band 13, 10.3 µm) imagery, GOES-16 Visible Imagery (Band 2, 0.64 µm) overlain with Radar imagery, and GOES-16 Visible Imagery alone (Click to enlarge)

A narrow ribbon of Slight RIsk was forecast for parts of the midwest on 13 Friday 2022, as shown below, and a few severe weather events occurred (SPC Storm Reports); they were well forecast. How did the Polar Hyperspectral Sounding forecast system perform on this day? The toggle above shows a 7-h forecast of CAPE (initialized at 1600 UTC and valid at 2300 UTC). It’s noteworthy that the forecast also shows a narrow corridor of instability. A similar toggle, but starting with the 0-h initial field of PHSnABI derived CAPE from the model at 2200 UTC, is here.

SPC Day 1 Outlook, 13 May 2022, issued at 2000 UTC (Click to enlarge)

The toggle below shows the 7-h forecast compared to the GOES-16 ABI Derived CAPE. A similar toggle, here, compares the 1-h forecast (initialized at 2200 UTC, valid at 2300 UTC) with the 2300 UTC Derived CAPE observed from GOES. The 7-h forecast below might be too far to the east; however, the developing convection associated with ribbon of instability is removed from the leading edge of the CAPE.

7-h forecast of CAPE from PHSnABI Modeling system and GOES-16 Derived Stability CAPE (overlain with GOES-16 ABI Band 13 Infrared imagery (10.3 µm) at 2300 UTC on 2300 UTC 13 May 2022 (click to enlarge)

Precipitation forecasts from this event (available at this website) are shown below, starting with two forecasts valid at 2300 UTC: a 3-h forecast from 2000 UTC and a 1-h forecast from 2200 UTC. They both show strongest convection over western IL, as observed. The 2000 UTC forecast also shows the break in convection over southern WI, also as observed.

PHSnABI forecasts of 1-h precipitation at 2300 UTC valid from initial times of 2000 and 2200 UTC on 13 May 2022 (Click to enlarge)
Accumulated 1-h precipitation from the PHSnABI model initialized at 2200 UTC on 13 May 2022; forecasts valid at 2300 UTC on 13 May, 0000 and 0100 UTC 14 May 2022 (Click to enlarge)

The PHSnABI modeling system accurately showed the corridor of instability over the Great Lakes, and convection did develop with this instability as observed. (Note: forecasts initialized before 1700 UTC did not produce precipitation; observations from the afternoon overpasses of NOAA-20 and Suomi-NPP perhaps supplied the necessary information leading to a better prediction of precipitation). Radar imagery over WI at 0054 UTC on 14 May 2022 is shown below. The initial (very narrow) line of convection did produce precipitation over Madison, but precipitation moved over Madison from the south after 0100 UTC.

Base Reflectivity at 0054 UTC on 14 May 2022 (click to enlarge)

GOES-18 ABI Imagery Comparisons

May 13th, 2022 |

NOAA and NASA recently released the first ABI (Advanced Baseline Imager) imagery from GOES-18. GOES-T was launched on March 1, 2022. (see the GOES-T launch as GOES-16 and GOES-17 monitored the rocket signature). GOES-18 is the third (of four) in the GOES-R series and is currently located above the equator at approximately 90W. GOES-18 is slated to become NOAA’s operational GOES-West in early 2023 after going through extensive post-launch testing. Also, see this CIMSS Satellite Blog post or this Satellite Liaison Blog post.

GOES-18 Compared to other GOES

Remapped GOES-16, -17 and -18 ABI data from 18 UTC on May 6, 2022.

While it is still very early in the post-launch test period, good qualitative agreement has been shown to other GOES imagers, except when comparing to GOES-17 during times it is affected by the Loop Heat Pipe issue. Of course, due to parallax and other reasons, there are expected to be differences, especially at larger view angles. The above loop as a mp4 and animated gif. Or versions that toggle between GOES-18 and GOES-16 only (mp4 and animated gif).

GOES-18 and GOES-16 Band 10 images at 14 UTC on May 6, 2022.

GOES-18 images of the western United States collected by the Advanced Baseline Imager (ABI) on May 6, 2022. The GOES-18 ABI band 10 (7.3 micrometers) image is on the left, while the GOES-16 image is on the right. Note that the data are in the same projection. Warmer brightness temperatures are mapped to warmer colors. Time animations (from 12 to 22 UTC) of these 2 panels are available for each band: 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, and 16 (mp4).

Remapped GOES-17 and GOES-18 Band 10 images at 18 UTC on May 6, 2022.

GOES-18 image of the United States collected by the ABI on May 6, 2022. The GOES-18 ABI band 10 (7.3 micrometers) image is on the right, while the GOES-17 image is on the left. This 2-panel “water vapor” image shows overall agreement, with less noise shown on GOES-18 compared with GOES-17. These GOES-18 ABI are early images, calibration improvements are possible. Time animations (from 12 to 22 UTC) of these 2 panels are available for each band: 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, and 16 (mp4).

3-panel Comparisons (GOES-17, -18, -16)

These 3.9 mircometer band comparisons are thanks to Scott Bachmeier. Direct links for the CA and NM cases of a CIMSS Satellite Blog.

ABI Instrument Response Functions

“Flight Model 3” or GOES-18 ABI Spectral Response Functions for the 10 infrared bands.

The ABI has 16 spectral bands, 2 in the visible, 4 in the near-infrared (or “near-visible”) and 10 in the infrared part of the electromagnetic spectrum. The instrument response functions can be found both on CIMSS and Calibration Working Group sites.


Thanks to the many (thousands) who made the GOES-18 ABI possible. These are GOES-18 ABI are early images (preliminary and non-operational, future calibration improvements are possible. geo2grid and McIDAS-X software was used in generating these images. More about GOES-16 and GOES-17.