Your Weather

To update your location please enter your ZIP code, city, state, airport code or country in the field below. Weather by E-mail: Forecast storm alerts. Weather E-Mail Alert Sign Up »

Next 12 Hours

Forecast data from the National Digital Forecast Database.

5 Day Forecast

• Saturday
• 
• High: 68 °
• Low: 50 °
• Mostly Cloudy

• Sunday
• 
• High: 68 °
• Low: 46 °
• Partly Cloudy

• Monday
• 
• High: 72 °
• Low: 50 °
• Clear

• Tuesday
• 
• High: 73 °
• Low: 52 °
• Partly Cloudy

• Wednesday
• 
• High: 73 °
• Low: 52 °
• Partly Cloudy

Southeast Alaska forecast discussion 
National Weather Service Juneau Alaska 
624 am akdt Sat may 25 2013 


Short term...scattered showers are expected this afternoon for 
many of the zones near the coast mountain range. Otherwise the 
stable conditions including diurnal cycles of sea stratus and fog 
are expected to be prevalent. Showers developing from the easterly 
flow features have below average confidence. The remainder of the 
short range forecast package has average confidence. 


A 500h low over the Seattle vicinity, as well as a second low over 
Alberta, are supporting synoptic-scale flow that includes east flow 
across most of b.C. The GOES infrared loop shows several small- scale 
vorticity features moving from over central b.C. And over the 
Panhandle. 


A 500h ridge extends west-southwest from over great Slave Lake and over the 
central Panhandle. We sometimes call a ridge aloft "dirty" if 
short waves are able to travel through it, even if these waves are 
weakening. In the present case, we have a dirty ridge that is 
weakening the short waves enough to limit precipitation, but the 
isentropic lift should prevail enough to generate the scattered 
showers discussed above. The isentropic lift is weak and difficult 
to identify S of Sumner Strait. 


The models point to a small low aloft about 300 nm S of Middleton 
Island, and the GOES infrared shows a limited area of cloud mass 
consistent to this cold core low aloft. This low will drift north but 
has almost no associated features lower than the 700h. 


A surface ridge of high pressure extends north from the North Pacific 
along to the vicinity of Icy Cape. The ridge axis will tilt in 
response to a 995 mb low about 400 nm S of Kodiak, and by 12z sun 
the result will be the ridge extending northwest along a line from 
Ketchikan to Sitka and northwest to Prince William Sound. 


The GOES infrared also shows the cloud shield associated with an occluded 
system with a triple point about 500 nm S of Kodiak. The NAM is 
accepted with a solution of 25 knots winds in the SW section of the 
offshore zone (pkz310) by 12z sun. The system discussed in this 
paragraph is not significant for any other zone in our area of 
responsibility through 12z sun. Please note the long range section 
for features moving toward our area from the SW. 


Models: the convection for this afternoon will be associated with 
east-southeast flow across the coast mountain range. Isentropic upglide is 
indicated for the flow moving past the upper levels of the coast 
mountain range on the two models that had best initialization: the 
NAM and the European model (ecmwf). 




.Long term...Upper high over northwest Canada will drift westward into southeast 
interior Alaska by Tuesday. Elongated upper low will drift eastward across the 
NE Pacific then stall over the far eastern part of the NE Pacific by Tuesday 
night. A general Ely flow will continue over Southeast Alaska through midweek. 
Models still struggling with details on shortwaves moving westward through 
the area...with the most concerning shortwave now over southern Alberta 
province. Looks like this feature will drift northwest through Sun night 
then drift westward across northern British Columbia early next week. Eventually the upper 
low to the south will lift northward through the area...likely during the 
latter half of next week. Ended up using a GFS/NAM blend mainly 
for the way they handled the winds over the Gulf for sun- Monday 
period. 


For sun into Monday...small upper low over the Gulf will drift northwest 
across the northern Gulf early in the period. This feature will 
interact with some of the moisture being advected in from the east-southeast 
and likely cause some rain over the NE Gulf area Sun morning. 
Would expect this precipitation to move out Sun afternoon as upper low 
pulls away from the area and short wave ridging moves in. The 
other area that might get some precipitation during this period is the 
far southeast...where some shortwave energy will move across from the east. 
This precipitation looks more showery...and by Monday afternoon...some 
models suggest potential for thunderstorms in the Hyder area. Did not put 
thunderstorms in yet due to model timing of shortwave features and 
position of best instability and low level convergence changing 
with each model run. GFS did show negative showalter index 
values...which would allow convection moving in from the east to 
survive longer even if lower level airmass remains on the cool 
side. 


For Monday night into midweek...looks like more shortwave energy 
will be moving in from the east during this time. Brought in more 
clouds to much of the area Monday night and Tuesday due to potential for 
middle-level clouds moving in from the east. Also went for a larger area 
of chance probability of precipitation especially by late Tuesday night due to the uncertainty 
on exact track of shortwave features. Blended in wpc probability of precipitation with 
previous forecast to do this. 


Better chance for precipitation should arrive for the latter half of the 
week as upper low lifts northward through the eastern Gulf. Kept in chance to 
likely probability of precipitation for most of the area Wednesday night into Friday. All in 
all...forecast confidence remains below average due to the upper 
air pattern we are in. 


Ajk watches/warnings/advisories... 
public...dense fog advisory until 8 am akdt this morning for akz017. 
Marine...none. 


&& 


$$ 


Jbt/rwt