Last Updated on Saturday, 08 March 2014 23:50
Issued: Mar 09, 2014 8:30 AM HST
Initial visible imagery of the day shows broken to overcast low clouds streaming over the islands from the east, with the open celled cumulus /cu/ that prevail being showery in appearance. With the prevailing wind flow being from the east, the majority of this cloudiness and moisture is affecting the windward, or eastern, portions of the islands.
On Kauai, the eastern half of the island is covered in broken to overcast showery cu, while the leeward half of Kauai, as well as the island of Niihau, and adjacent waters, are under mostly sunny skies. On Oahu, broken low clouds prevail, with the showery cu focused on the windward slopes, with more stable stratocumulus /sc/ and isolated showery cu occasionally spreading leeward. Broken low clouds are stacked along windward Molokai slopes, with scattered sc spreading leeward. Broken to overcast showery cu prevail over the windward slopes of Maui, and over the north side of Lanai, but leeward Maui and Kahoolawe are under mostly sunny skies. On the Big Island, broken to overcast showery cu prevail over the lower windward slopes, coast and adjacent waters, with a relatively narrow line of showery towering cu located just offshore the sunny Hamakua coast that stretches toward waters just east of Hilo to over Cape Kumukahi. The broken to overcast low clouds are over the coast and slopes from Laupahoehoe to Hilo to near Volcano, and aside from a patch of broken to overcast sc near Waipio and waimanu valleys, the remainder of the island is under mostly sunny skies this morning. Snow on the summit still seen in visible imagery, but not to the extent that it was at the end of last week.
The showery cu near and over the islands extend up to 150 to 200 miles east of the islands, and while near shore leeward waters are mostly sunny with few low clouds prevailing, cooler cloud tops are noted over offshore waters southwest of Kauai. Cloud top temperatures in this area have been cooling over the past couple of hours, indicating that the clouds are growing vertically, with latest measurements yielding cloud tops near 17 thousand feet. Similar cloud top temperatures were over east Maui slopes a short while ago, and have since warmed slightly, but cool cloud top temperatures continue to be observed within the showery cloud line over windward Big Island waters. Low clouds near the islands are moving toward the west at 15 to 20 mph.
Water vapor imagery shows mostly dry air aloft over the islands, with a west-northwest flow aloft. An eastward-moving trough aloft is east of the islands along a line from 30°N 145°W to 20°N 150°W, with the southern edge of the trough about 300 miles east of windward Big Island.