Saturday morning update:
The National Weather Service is predicting a double dose of nastiness for Southcentral Alaska this weekend as two strong fronts bring rain, freezing rain and wind well into next week.
"We have what looks to be a snow event starting on Saturday morning, converting into a rain event late Saturday afternoon and continuing into Sunday," said David Kochevar, a meteorologist with the Weather Service in Anchorage. "We're expecting high temperatures to continue in the mid-30s to low- to mid-40s through Monday and the early part of the work week."
A special weather statement issued by the Weather Service on Thursday evening said light snow would hit both Anchorage and the Kenai Peninsula early Saturday, mixing with freezing rain later in the day and turning to "straight rain" as temperatures rise above freezing on Saturday night. Similar weather should strike the Mat-Su region.
Andy Dixon, also a National Weather Service meteorologist, said he hopes the period of freezing rain will be short. Though williwaws or chinooks -- wet, windy warm spells in the middle of winter -- can be expected in Anchorage, Dixon said this one would be unusual because the freezing level was predicted to be especially high. Rain might occur at elevations as high as 5,000 feet, he said.
Forecasters are calling for a one-two punch from the south, with a secondary low pressure system to move through the area on the heels of the first on Sunday afternoon and Monday morning.
Strong southeast williwaw winds are expected along Turnagain Arm and higher elevations in Anchorage but "the Anchorage Bowl will likely not see strong winds until the secondary low moves through the area."
The statement said it was too early to predict the strength and timing of the winds or rainfall in the secondary system. Dixon said he was not expecting damaging wind to hit most of Anchorage: "It probably won't exceed 30-35 miles an hour." But the spike in temperature will be big. "I would not be surprised at all to see some parts of town in the lower 50s," he said.
"The worst conditions will be in the coastal mountains and towns on the Gulf of Alaska, Cordova and Seward," Kochevar said.
The statement said "there is a possibility of a prolonged rain event in the Prince William Sound area." However, it noted, "it is too early to be certain whether the front will linger" through the week or push eastward quickly.
The potential for flooding is particularly worrisome, said Kochevar. "With all of the rivers and streams being mostly ice-covered right now, there's a concern about overflow."
The Weather Service statement said overflow is "likely" and could lead to "minor flooding of low lying areas."
By MIKE DUNHAM