{"id":12775,"date":"2013-04-30T19:57:58","date_gmt":"2013-04-30T19:57:58","guid":{"rendered":"http:\/\/cimss.ssec.wisc.edu\/satellite-blog\/?p=12775"},"modified":"2013-05-01T17:25:55","modified_gmt":"2013-05-01T17:25:55","slug":"fogstratus-along-the-central-california-coast","status":"publish","type":"post","link":"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/archives\/12775","title":{"rendered":"Fog\/stratus along the central California coast"},"content":{"rendered":"
\"GOES-15<\/a>

GOES-15 IR brightness temperature difference “Fog\/stratus product” (click image to play animation)<\/p><\/div>\n

The San Francisco Bay Area<\/strong><\/a> National Weather Service forecast office made use of a variety of satellite images and products to monitor the development of fog and stratus clouds along the central California coast during the pre-dawn hours of 30 April 2013<\/strong><\/a>. From their forecast discussion:<\/p>\n

AREA FORECAST DISCUSSION
\nNATIONAL WEATHER SERVICE SAN FRANCISCO BAY AREA
\n451 AM PDT TUE APR 30 2013<\/strong><\/p>\n

.DISCUSSION…AS OF 3:20 AM PDT TUESDAY…SATELLITE AND SURFACE OBS INDICATE ONLY SOME MINOR POCKETS OF LOW CLOUDS AND PATCHY FOG.<\/strong>
\n RIGHT NOW HALF MOON BAY IS THE ONLY SPOT REPORTING REDUCED VISIBILITIES WHILE MONTEREY NOW HAS A CEILING. DETAILS FROM THE OVERNIGHT<\/strong>
\n SATELLITE FOG PRODUCT ARE A BIT DIFFICULT TO MAKE OUT ALTHOUGH LOOKS LIKE THE AREAS ARE VERY SMALL IN NATURE.<\/strong><\/p>\n

Using the 4-km resolution GOES-15 11-3.9 \u00c2\u00b5m IR brightness temperature difference (BTD) “fog\/stratus product” with the default gray-scale enhancement applied (above; click image to play animation)<\/strong><\/em>, it was indeed difficult to unambiguously determine the motion and areal coverage of the darker fog and stratus features (especially in the Monterey Bay area). Applying a tailored color enhancement<\/strong><\/a> to that same GOES-15 BTD fog\/stratus product does help a little to highlight some of the more well-defined fog and stratus features (with a darker orange color),<\/em> but there is also a tendency to produce large areas of noisy “false alarm” fog\/stratus signals (yellow color enhancement)<\/em> over much of the inland areas of central California.<\/p>\n

In the Aviation section of their forecast discussion, mention was made of the GOES-R Marginal Visual Flight Rules (MVFR) product, which is produced using an algorithm designed for the upcoming GOES-R satellite (but applied to current GOES-15 data):<\/p>\n

MONTEREY BAY AREA TERMINALS…SHORT LIVED MVFR THIS MORNING. VIIRS DAY NIGHT SATELLITE AND GOES-R MVFR PROBABILITIES INDICATE CLOUD DECK IS PATCHY.<\/strong><\/p>\n

This GOES-15\u00c2\u00a0product (below; click image to play animation)<\/strong><\/em> did indeed show that the areas of 50-80% MVFR Probability were patchy in nature in the vicinity of Monterey Bay.<\/p>\n

\"GOES-15<\/a>

GOES-15 MVFR Probability product (click image to play animation)<\/p><\/div>\n

Other GOES-R Fog\/Low Stratus products (produced as part of the GOES-R Proving Ground<\/strong><\/a> activities at CIMSS\/ASPB) include an Instrument Flight Rules (IFR) Probability<\/strong><\/a> product, a Low Instrument Flight Rules (LIFR) Probability<\/strong><\/a> product, and a Low Cloud Thickness<\/strong><\/a> product.<\/p>\n

Mention was also made of the Suomi NPP VIIRS 0.7 \u00c2\u00b5m Day\/Night Band, which provided a high spatial resolution (750 meters, re-mapped onto a 1-km AWIPS grid)<\/em> “visible image at night” (below)<\/strong><\/em>, helping to confirm the spotty nature of the coverage of fog\/stratus in the Monterey Bay area.<\/p>\n

\"Suomi<\/a>

Suomi NPP VIIRS 0.7 \u00c2\u00b5m Day\/Night Band image<\/p><\/div>\n

Meanwhile, fog and stratus were more widespread across the southern California coast and adjacent offshore waters – for more details, see the GOES-R Fog Product Examples<\/strong><\/a> site.<\/p>\n

 <\/p>\n","protected":false},"excerpt":{"rendered":"

The San Francisco Bay Area National Weather Service forecast office made use of a variety of satellite images and products to monitor the development of fog and stratus clouds along the central California coast during the pre-dawn hours of 30 April 2013. From their forecast discussion: AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE SAN FRANCISCO BAY […]<\/p>\n","protected":false},"author":18,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":""},"categories":[21,13,43,34,49,48],"tags":[],"class_list":["post-12775","post","type-post","status-publish","format-standard","hentry","category-aviation","category-fog-detection","category-goes-15","category-goes-r","category-suomi_npp","category-viirs"],"acf":[],"_links":{"self":[{"href":"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/wp-json\/wp\/v2\/posts\/12775","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/wp-json\/wp\/v2\/users\/18"}],"replies":[{"embeddable":true,"href":"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/wp-json\/wp\/v2\/comments?post=12775"}],"version-history":[{"count":19,"href":"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/wp-json\/wp\/v2\/posts\/12775\/revisions"}],"predecessor-version":[{"id":12795,"href":"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/wp-json\/wp\/v2\/posts\/12775\/revisions\/12795"}],"wp:attachment":[{"href":"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/wp-json\/wp\/v2\/media?parent=12775"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/wp-json\/wp\/v2\/categories?post=12775"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/wp-json\/wp\/v2\/tags?post=12775"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}