Scientific Forecaster Discussion
Southcentral and southwest Alaska forecast discussion
National Weather Service Anchorage Alaska
200 PM akdt Monday Mar 10 2014
Analysis and upper levels...
a much more active weather pattern is in store for this week
compared to last week. The mean upper trough position is located
over the eastern Bering Sea...an will remain there through the short
term portion of the forecast (thursday afternoon). There is an upper
low on the eastern side of the trough...straddling the Alaska
Peninsula and moving to the north-northeast. A strong occluded front
associated with this low is currently pushing into south central
Alaska. The jet stream is fairly zonal from Asia across the North
Pacific (generally between 30 and 40 degrees latitude) and then
curves northward across the Gulf of Alaska. An upper low to the
southwest of the western Aleutians is moving eastward as it "rides"
the jet stream.
the numerical models are in fairly good agreement and maintain good
run-to-run consistency. Normally this would give high confidence in
the forecast...but this is offset by the strong nature of the
weather systems that creates some significant local effects that can
be difficult to forecast. Therefore forecast confidence is near
Short term forecast...
for south central Alaska...the occluded front will pass through the
area tonight. The remains of the upper low will push through later
Tuesday (by this time a weak upper open-wave trough). Downslope
effects will keep areas along Cook Inlet (north of clam gulch)
fairly dry through Tuesday...with some passing showers and/or
flurries. Coastal areas will see fairly significant precipitation
through tonight and then tapering off on Tuesday. On Tuesday night
a short-wave trough will round the base of the main trough. This
should weaken the downslope with the change in upper/medium level wind
direction and bring a better chance of precipitation to Anchorage
and surrounding areas. Turnagain and higher elevation winds will
continue to be fairly strong through
On Wednesday the low that is currently southwest of the western
Aleutians will have moved to south of the eastern Aleutians. An
occluded front from this low will push into south central Alaska
Wednesday afternoon. The upper low will then swing north on the east
side of the mean Bering trough on Thursday.
Turnagain and higher elevation winds will continue to be fairly
strong through Thursday afternoon...with stronger impulses Tuesday
afternoon and later Wednesday through Wednesday night. The gradient
Wednesday night looks strong enough that winds may approach warning
For southwest Alaska...the northern portion of the low straddling
the Alaska Peninsula will push through southwest Alaska tonight.
Some moisture and precipitation will continue even behind this
low...with some drying expected once the next upper trough swings
through the area late Tuesday night. Precipitation will spread north
through the area again late Wednesday into Thursday as the next low
(the one currently southwest of the western aleutians) arrives.
public...Winter Storm Warning 125.
Marine...Storm Warning 119.
Gale Warning 120 125 170 172 176 177 178 179 180 181 185.
Heavy freezing spray 160 179 180.
Ludwig Mar 14