454 
fxak67 pajk 192101 
afdajk 


Southeast Alaska forecast discussion 
National Weather Service Juneau Alaska 
1259 PM akdt Friday Mar 19 2010 


Short term...a weakening occluded front will move across most 
of Southeast Alaska tonight...but stall over the S-Central Area by late 
tonight. The front will dissipate there Sat. A low well S of the 
area will move north-northeast toward the charlottes Sat. Model preference 
for the short term period was the 00z European model (ecmwf). 


Main forecast concern is how fast the precipitation with the front 
diminishes as it moves inland. Upper support for the front is 
beginning to outrun the lower levels of the front...and this will 
start a diminishing trend in precipitation coverage as the front heads 
eastward. Precipitation will rapidly diminish after lower part of front GOES 
by this evening...with just a few showers expected behind it over 
the northern area later this evening. Precipitation will hold on longest 
across the S-Central Area where front will stall...and the last 
remnants of precipitation with the front should disappear Sat morning as 
the front dissipates. The few leftover showers over the northern area 
will also end later Sat morning as flow becomes more offshore. 
Should see some clearing Sat afternoon as the offshore flow 
increases. 


Winds will be strongest just ahead of the front but the pre- 
frontal winds will be decreasing as the front weakens. Will 
generally have Small Craft Advisory level winds over the southeastern area at beginning of 
tonight period...and those should drop below Small Craft Advisory by late evening. 
Seas will remain on the high side though due to swell so Small Craft Advisory due 
to seas will be kept through Sat over the Gulf coastal waters. 


&& 


Long term...for the start of the long term high pressure over 
the Panhandle with offshore flow will keep the region dry. 
Pressure gradient over the north will keep smcr winds in north and S Lynn 
Canal with breezy conditions in pagy. Possible windy conditions 
at pagy so will need to keep an eye on that. Weak low pressure 
system will tack north from the Pacific just off the Queen Charlottes sun 
evening into Monday. Expecting this low to dissipate by Monday evening 
and associated front to bring chance precipitation only to southern 
zones with offshore flow over the north central Panhandle. Return to 
onshore flow with another ridge by middle week then next low in the 
west Gulf west. Upper level trough over the Alaska Gulf with keep a series of 
short waves moving over the Panhandle middle week. Details on these 
lows not well depicted at this time. 


Models were in fair agreement at the start of the long term but 
by day 4 diverge significantly. Ec initialized better at upper 
levels and surface this morning with the NAM and GFS a bit slower. Ec 
run to run has been a bit more consistent as well. Blended 
inherited grids out to day 4 with 00z ec then blended inherited 
grids with HPC guidance. HPC leaned more toward ec as well as panc so 
border issues were minimal. 


Forecast confidence is a bit below average due to poor resolution 
of middle week short waves. 


Ajk watches/warnings/advisories... 
public...none. 
Marine...Gale Warning for pkz043. 
Small Craft Advisory for 
pkz011-013-021-022-032>036-041-042-051- 
052. 


&& 


$$ 


Rwt/prb 

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