Using GOES imagery over northern Alaska
GOES-11 visible images (Animated GIF)
Given the rather large satellite viewing angle (or “zenith angle”) of geostationary satellites positioned over the Equator, one would think that the imagery would not be of much value over places such as far northern Alaska. However, a forecast discussion issued by Fairbanks, Alaska mentioned the utility of GOES visible imagery for monitoring fog and stratus along western parts of the Arctic coast of Alaska:
NORTHERN ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE FAIRBANKS AK
347 AM AKDT SAT JUL 5 2008.DISCUSSION…
OVER THE ARCTIC…GOES VIS LOOP SHOWING AN EXTENSIVE AREA OF STRATUS OVER AREAS FROM BARROW NORTH THROUGH SOUTHWEST…INCLUDING MOST OF ZONE 201. THIS STRATUS IS MISSED BY THE LOW LEVEL RH PROGS ON BOTH THE GFS AND NAM MODELS. THIS AREA IS LIKELY TO REMAIN FOGGY THROUGH TONIGHT WITH ONSHORE FLOW CONTINUING…ALTHOUGH VISIBILITY MAY COME UP SOME DURING THE AFTERNOON AND EARLY EVENING. DENSE FOG HEADLINES WILL BE POSTED FOR ZONES 201 AND 202. THE EASTERN ARCTIC COAST IS LIKELY TO REMAIN FOG-FREE.
GOES-11 visible imagery at 30-minute intervals on 05 July 2008 (above) does indeed do a fairly good job of showing the movement of the bank of fog and stratus that had moved inland over locations such as Barrow (PABA), Wainwright (PAWI), and Point Lay (PLIZ) during the day. A surface meteorogram for Wainwright, Alaska (below) shows that the surface visibility remained at or below 1 mile during much of that particular day, and temperatures dropped below freezing as onshore winds persisted.
Wainwright AK surface meteorogram
Other features of interest to note on the GOES-11 visible imagery shown above:
- a long smoke plume from a wildfire, which originates just southeast of Fort Yukon (PFYU) and blows southwestward across central Alaska
- the high amount of sea ice that remained in the Arctic Ocean north of Alaska
- the snow-covered mountains of the Alaska Range in the southern part of the state — between Minchumina (PAMH) and Talkeetna (PATK) — which includes the summit of Mount McKinley (Denali) at 20,320 feet (6,194 m)
- northern Alaska experiences 24 hours of continuous daylight during this part of the summer