073 
fxak68 pafc 191500 
afdafc 


Area forecast discussion...corrected 
southcentral and southwest Alaska 
500 am akst Wednesday Nov 19 2008 


Corrected for warnings. 


Model discussion... 
models are slightly more consistent in the Middle Range and short term 
than they have been over the past few days...but still not excellent. 
Trend is toward little change from the current forecast in the short 
term with a 50/50 blend toward the 00z GFS in the Middle Range. 
Reasoning behind this is that the GFS solution has been further south 
but over the past couple of runs the other models have trended toward 
that solution. Past 84 hours the 19/00z European model (ecmwf) was chosen as the model 
of the day for how it handled the next low pressure system moving in 
from the west. This is also in line with the HPC solution which 
leaned heavily on the European model (ecmwf). 


Analysis and upper levels... 
current upper level pattern shows a closed low center over the Gulf 
of Alaska with a ridge over the Bering Sea. The surface analysis 
shows a similar pattern with a complex low system rotating over the 
Gulf of Alaska and a blocking surface high over the eastern Bering. 
As the low in the Gulf continues to maintain its position several 
impulses will move southward into the base of the trough continuing 
to provide upper level support for the surface features. Between the 
high and the low a tightened gradient and a strong upper level jet 
are contributing to gusty northerly winds at the surface as well as 
continuing to strengthen the long wave trough. 


Short term forecast... 
east of the Alaska Range...the low pressure system in the Gulf of 
Alaska is bringing moisture to the south central region. As 
mentioned previously the northerly flow ahead of this front combined 
with some cold air damming to the north is causing gusty winds 
through channeled areas...particularly in north-south oriented passes 
like Thompson Pass. The presence of a low level jet over the Kenai 
Peninsula will bring wind shear to some areas and gusty surface winds 
to others. Storm force winds will be present all across the marines 
today as the temperature gradients and channeling enhance the local 
winds. Precipitation will be confined to the coastal areas...and 
temperatures will keep it a mix along the Gulf Coast and over Kodiak 
today. This pattern will continue through Friday as the low in the 
Gulf shifts slightly northward and continues to push frontal bands 
onshore. 


West of the Alaska Range...the northerly flow over the western 
Mainland will cause gusty winds through channeled areas along the Alaska 
Peninsula today...with some stronger low level winds along the Kuskokwim 
Delta. Storm force winds are expected in the marine zones along the 
coast as the gusty winds move off the Mainland. Otherwise cold temperatures 
and nice weather will continue for the Mainland through Friday 
morning. 


In the Aleutians...a strong low will move into the western Aleutians 
from the south beginning on Thursday. As this low gains the support 
of the cold air advecting in from Russia it will continue to 
strengthen. This will bring upper gale force winds to the Aleutians 
on Friday. However as the front associated with this system 
progresses eastward it will gradually weaken. By Friday morning the 
systems will bring wind and rain to the central Aleutians. 




Long term forecast...the low in the Aleutians on Friday will 
continue to progress eastward and gradually become absorbed by the 
low in the Gulf. This will cause the entire pattern to retrograde 
and by Saturday most of the Mainland will see precipitation. Current 
temperature forecasts indicate this will be snow for the most part. 
After Saturday a ridge builds into the eastern Bering again but this 
pattern looks to be weaker than our current pattern so it will not 
remain nearly as stagnant for next week. 


Aer/alu...watch/warning summary 
public...none 
marine...storm 120 130 132 138 150 
gale 125 140 141 155 160 165 172 175 176 180 185 
heavy freezing spray 160 180 
fire weather...none 


Lewf Nov 08 

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