157 
fxak67 pajk 182037 
afdajk 
Southeast Alaska forecast discussion 
1100 am akdt Friday Jul 18 2008 


Short range...major upper low main center is over Bethel this 
morning with a second center developing near Middleton isl. 
Interestingly the coldest temperature at 500 hpa is Kodiak -27c as per 
the 12z radiosonde observation. Certainly the energy will be focused in the eastern 
low center. Mondo jet 250 mb 12z due west from almost the S tip 
of Korea to an exit just off Sitka. With the cold air aloft we 
agree with the middle shifts idea to select forecast with most 
development in the upper left quadrant ergo the eastern Gulf. 


Most intense problem of the day is not the near gale winds in 
July but the quantitative precipitation forecast and hence Hydro problems. By midday today new 
jet axis SW up to 100 knots over pags. There has been a fairly good 
connection to the tropics back in the western Pacific. Amounts 
forecasted are highly model dependent. 12z NAM-40 selected as the 
best depiction for quantitative precipitation forecast and developing wave on the front which 
will be 997 mb just off Cape Spencer 12z Sat. Looked at the 700 
mb flow for The Straight shot of moisture going up Lynn Canal to 
dump in the Skagway-taiya river area for problems. Will decide 
later in the shift for how much flooding. Wet cool and somewhat 
windy weekend. Could we please have a summer? 


Long range...major run-to-run model variability now being 
exhibited by European model (ecmwf) as well as GFS. Forecast confidence on timing 
and intensity of surface pressure and wind fields low for the 
extended range forecast period. Still looks like a fairly wet 
week but models are now suggesting a longer break in the precipitation 
beginning early next week. Forecast confidence in precipitation from day 
4 Onward now moderate. 


Ensemble means for GFS...ECMWF...and Canadian all tending to wash 
out major features and this is addressed by HPC. Opted for a 
blend of UKMET...GFS and current grids and specifically excluded 
European model (ecmwf) today due to a 997mb bulls eye low in the east-central Gulf 
on 24/25 July that was not there yesterday. 


Tropical moisture tap will continue from the end of the short 
range period into early next week. Moisture source for the second 
half of the week looks more like the Bering Sea. A large upper 
level low over the western interior will draw down cold upper air 
from the Arctic and...as it turns the corner over the 
Aleutians...pick up Gulf moisture before arriving over the 
Panhandle. Certainly not expecting snow at lower elevations...but 
significantly colder middle and upper level temperatures are on the 
way so snow levels will be coming down. 




Ajk watches/warnings/advisories... 
public...none. 
Marine...Small Craft Advisory for 
pkz011>013-021-022-031>036-041>043-051-052. 


$$ 


Jcc/fritsch/bowley 

National Weather Service Glossary of Abbreviations

Non-Expanded Version (with abbreviations)