868 
fxak68 pafc 231436 
afdafc 


Area forecast discussion 
southcentral and southwest Alaska 
500 am akst Monday Nov 23 2009 


Analysis and upper levels... 
in the upper-lvls...a broad trough envelops much of the aor...with an 
upper-low over the far northern Bering and an upper-ridge over the 
Copper River basin. At the surface a storm-force low NE of Kodiak is 
moving northwest towards the S Kenai Peninsula and Cook Inlet 
region...with the associated front approaching the coastal areas of 
Prince William Sound. Further west a low is present just south of 
Cape Newenham and moving east and onshore Bristol Bay. Also a weak 
low is over the western Bering rotating southeast. Surface features 
due to impact the aor in the coming days are in their developing 
periods. One of them is off the S tip of the Kamchatka peninsula 
moving east towards the west Bering/Aleutians...and the other is a 
deepening low over the north central Pacific moving northeast towards 
the Gulf of Alaska. 


Model discussion... 
models are satisfactorily capturing the major features across the 
aor. In general the low moving into the S Cook Inlet region Monday 
afternoon will weaken...with the NAM capturing this best. All 
solutions reasonably depict the next low moving into the Gulf of Alaska 
Tuesday into Wednesday...though the GFS tends to consolidate the 
energy while the other solutions elongate the system a bit more. The 
remnants of the system appear to move onshore on Wednesday night. In the 
west the weak low in the Bering will weaken as it moves southeast and 
dissipates around the pribiloff islands. The system developing off 
the Kamchatka peninsula will move east and into the west Bering Tuesday 
afternoon and evening...with models reasonably similar through the 
Middle-Range period...albeit the GFS is strongest. 


Short term forecast... 
southcentral... 
rain and snow continuing across the Kenai Peninsula and Prince 
William Sound as the storm-force low and associated front move 
ashore...tapering to showers Tuesday morning...except where southerly 
flow will continue to support precipitation across eastern Prince 
William Sound. Through Monday...heaviest snow will be over higher 
elevations and particularly Turnagain Pass where in excess of one 
foot of snow is expected through early Tuesday. Strengthening 
pressure gradient to support strong winds through Thompson Pass...and 
when coupled with falling and blowing snow...looks to yield blizzard 
conditions late Monday afternoon through early Tuesday morning. 
Strong east winds of 60 to 75 miles per hour developing along Turnagain Arm 
Monday afternoon as front passes through. Precipitation through the 
Anchorage bowl and mat-su valley looks to be retarded by downsloping 
conditions...though some periods of light snow still possible mainly 
along the hillside. Some warmer air trying to nose into the interior 
of southcentral may yield a mix of rain and snow mainly along the 
hillside/mountains. Front moving through will shift winds to the 
southeast into the Anchorage bowl...though strongest winds will be 
along Turnagain Arm and higher elevations. Winds begin to diminish 
overnight Monday into Tuesday. The next low moving up the Gulf looks 
to reinforce precipitation over Prince William Sound Tuesday and 
Wednesday. 


Southwest... 
periods of snow over the kuskowim Delta/valley...except rain and snow 
over Bristol Bay closer to the dying low pressure system moving 
ashore there through Tuesday. Moisture from the low moving into Cook 
Inlet nosing additional moisture into the region and helping to 
sustain precipitaton. Areas of blowing snow coupled with falling snow 
bringing yielding localized blizzard conditions along the kuskowim 
Delta coast...ending by middle-day Monday as the Bristol Bay low 
dissipates. 


Bering Sea/Aleutians... 
snow showers giving way to steadier rain and snow over the Aleutian 
chain as another low pressure system moves through Tuesday and 
Wednesday. 


Long term forecast... 
pattern to remain active as upper-trough remains predominant across the 
aor...with a series of low pressure systems rotating through the Gulf 
and Bering into this weekend. 


Aer/alu...watch/warning summary 
public...Blizzard Warning...131 155 
High Wind Warning...101 
marine...storm...120 125 130 
gale...351 352 411 413 414 129 132 140 150 155 160 165 170 
171 172 175 176 179 180 185 
heavy freezing spray...412 414 160 179 180 


Jam Nov 09 

National Weather Service Glossary of Abbreviations

Non-Expanded Version (with abbreviations)