GOES-17 IFR Probability Fields now available in RealEarth

December 1st, 2021 |
RealEarth depiction of GOES-17 IFR Probability fields, 1200-1230 UTC on 1 December 2021 (Click to enlarge)

RealEarth has added GOES-17 IFR Probability Fields to its product suite (GOES-16 IFR Probability fields have been available in RealEarth for some time). They can be accessed most simply by entering ‘IFR Probabilty’ in the RealEarth search box. At present only the ‘PACUS’ domain (the GOES-17 equivalent of the GOES-16 ‘CONUS’ domain) is available, at 5-minute time-steps. An example over western Washington and offshore waters is shown above.

Radiation fog across the Lower Mississippi Valley and Gulf Coast

November 7th, 2021 |

GOES-16 MVFR Probability, IFR Probability, Low IFR Probability, Cloud Thickness products, along with “Red” Visible (0.64 µm) images [click to play animated GIF | MP4]

The suite of nighttime GOES-16 (GOES-East) Fog / Low Stratus products — Marginal Visual Flight Rules (MVFR) Probability, Instrument Flight Rules (IFR) Probability, Low Instrument Flight Rules (LIFR) Probability, and Cloud Thickness — along with the subsequent daytime “Red” Visible (0.64 µm) images (above) showed the increasing areal coverage of vertically shallow (Cloud Thickness values less than 1000 feet) radiation fog across parts of Texas, Louisiana, Arkansas and Mississippi on 07 November 2021. The surface visibility was reduced to zero at a few sites, with cloud ceilings as low as 100 feet being reported. Visible images showed that this shallow fog layer then quickly dissipated within a few hours after sunrise.

This fog was forming due to optimal radiational cooling conditions — light winds, along with a general lack of cloud cover — beneath a ridge of high pressure over that region (below). Surface air temperatures dropped into the 30s and 40s F across much of the area where this fog formed.

GOES-16 IFR Probability product at 0901 and 1201 UTC, with overlays of mean seal level pressure at those times [click to enlarge]

GOES-17 Fog/Low Stratus (FLS) product availability in AWIPS

October 18th, 2021 |

GOES-17 MVFR Probability over the PACUS Sector [click to play animation]

The suite of Fog/Low Stratus (FLS) products derived using GOES-17 (GOES-West) data within the PACUS Sector (above) became available via the Satellite Broadcast Network (SBN) for AWIPS on 18 October 2021. Two examples are shown below: one centered over Oregon, and the other centered over the Big Island of Hawai’i. The 4 products are Marginal Visual Flight Rules (MVFR, cloud ceiling 1000 to 3000 feet above ground level and/or visibility 3 to 5 miles) Probability, Instrument Flight Rules (IFR, cloud ceiling 500 feet to less than 1000 feet and/or visibility 1 to less than 3 miles) Probability, Low Instrument Flight Rules (LIFR, cloud ceiling less than 500 feet and/or visibility less than 1 mile) Probability and Cloud Thickness. 

GOES-17 MVFR Probability (top left), IFR Probability (top right), Low IFR Probability (bottom left) and Low Cloud Thickness (bottom right) [click to play animation]

GOES-17 MVFR Probability (top left), IFR Probability (top right), Low IFR Probability (bottom left) and Low Cloud Thickness (bottom right) [click to play animation] 

GOES-17 FLS products are also being produced by CIMSS over the Alaska region (below) — which are being distributed via an LDM feed.

GOES-17 MVFR Probability (top left), IFR Probability (top right), Low IFR Probability (bottom left) and Low Cloud Thickness (bottom right) [click to play animation]

A library of FLS applications can be found on the GOES-R Fog Product Examples site, and FLS Forecaster Training is available here.

River valley fog across the Mid-South

August 23rd, 2021 |

GOES-16 Night Fog BTD (10.3-3.9 µm) and “Red” Visible (0.64 µm) images, with and without plots of Ceiling/Visibility [click to play animation | MP4]

GOES-16 (GOES-East) Night Fog BTD (10.3-3.9 µm) and “Red” Visible (0.64 µm) images on 23 August 2021 (above) showed the nighttime formation of widespread river valley fog across parts of the Mid-South and adjacent Appalachians — followed by morning fog dissipation once solar heating initiated boundary layer mixing. With surface high pressure in place over the area, light winds helped to provide ideal conditions for strong radiational cooling and fog formation; note that the surface visibility was reduced to zero at a few sites in Tennessee. Much of that same region had recently experienced heavy rainfall (7-day accumulation | 7-day percent of normal), particularly in Tennessee as discussed in this blog post.

Suomi NPP VIIRS Day/Night Band (0.7 µm) images (below) displayed a subtle signature of some of the tendrils of river valley fog, and their growth during the ~90 minutes between the two satellite overpasses.

Suomi NPP VIIRS Day/Night Band (0.7 µm) images, with plots of Ceiling/Visibility [click to enlarge]