High Wind Watch 4, NWS Anchorage, AK

685 
WWAK71 PAFC 020032
NPWAER

URGENT - WEATHER MESSAGE
National Weather Service Anchorage AK
332 PM AKST Wed Mar 1 2017

AKZ131-021530-
/O.UPG.PAFC.HW.A.0004.170302T2100Z-170303T1500Z/
/O.NEW.PAFC.HW.W.0003.170302T1800Z-170303T2100Z/
Northeast Prince William Sound-
Including the cities of Valdez and Thompson Pass
332 PM AKST Wed Mar 1 2017

...HIGH WIND WARNING IN EFFECT FROM 9 AM THURSDAY TO NOON AKST
FRIDAY...

The National Weather Service in Anchorage has issued a High Wind
Warning, which is in effect from 9 AM Thursday to noon AKST
Friday. The High Wind Watch is no longer in effect. 

* LOCATION...Valdez to Thompson Pass.

* WIND...North to east winds 40 to 65 mph with gusts to 75 to 85 
mph.

* TIMING...Winds will steadily increase overnight tonight, with a
  more marked increase Thursday morning into warning levels.
  Expect warning level winds to continue and peak overnight
  Thursday into Friday. Winds will fall below warning levels late
  Friday morning, but remain elevated through the day. 


* IMPACTS... Travel may be difficult. Trees may be blown over. 
  Loose debris can be moved and damage property. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A high wind warning means a hazardous high wind event is expected
or occurring. People are urged to secure loose objects that could
be blown around or damaged by the wind.

&&

$$

Southcentral and Southwest Alaska Forecast Discussion
National Weather Service Anchorage AK
352 PM AKST Tue Feb 28 2017

.ANALYSIS AND UPPER LEVELS...
An upper level trough continues to dig southward across the
western Gulf of Alaska, supporting a surface low in the Gulf.
To the west, the ridge continues to amplify across the Western
Bering, with broad high pressure at the surface. The pressure
gradient between these two features has been generating gusty
gap winds along the north Gulf coast. The mixing associated
with these winds has kept overnight temperatures warmer.

&&

.MODEL DISCUSSION...
Models are in generally good agreement today in capturing the
gusty winds across portions of central Bristol Bay and the
Kuskokwim Delta. Models are also in general agreement of the
outflow winds very gradually weakening through the evening hours.
The high resolution models are still performing the best at
capturing these gap winds and as a result were favored for the
forecast. In addition, models are generally in agreement of the
trough digging southward and the intensification of the upper
level low as it pinches off.

&&

.AVIATION... Expect VFR conditions and gusty northerly winds to
persist through Wednesday morning.

&&

.SHORT TERM FORECAST SOUTHCENTRAL ALASKA (Days 1 and 2)...
In two words: cold, windy. The upper level pattern remains pretty
steady state for the next 48 hours. The only precipitation over
the area will remain over Gulf waters as several disturbances
rotate around the upper low pressure. Gusty wind will continue
to be the main forecast issue elsewhere. The surface pressure
gradient will stay compressed along the north gulf coast,
continuing gap winds in favored locations. Mountain-wave activity
will weaken in the Valdez area tonight, so gusts, while still
continuing, will not be as severe as last night and this morning.
Winds will continue at the same level through the pass.

The gradient shifts slightly tonight, favoring more winds in the
Matanuska Valley with gusts into the 40s. This shift will also
bring more gusty winds into the Cook Inlet region with the
strongest gusts right along the Inlet. While the air mass is much
colder, these winds will keep temperatures from dropping further.

On Thursday, winds will pulse upward along the Gulf coast once
again with the potential to be stronger than the current event.
Keep an eye on the forecast for further updates.

&&

.SHORT TERM FORECAST SOUTHWEST ALASKA (Days 1 and 2)...
With high pressure over the Bering and low pressure over the
Gulf of Alaska, northerly flow will continue into Thursday. The
northerly winds will bring down dry, colder air from the north
and also help to keep skies clear. With unstable conditions and
shortwaves moving through the area, gusty winds are expected
through tonight and into Wednesday. The combination of winds and
cold temperatures will bring cold wind chills for much of
southwest Alaska tonight and Wednesday morning.

&&

.SHORT TERM FORECAST BERING SEA/ALEUTIANS (Days 1 and 2)...
High pressure over the central Bering will keep most of the
activity out west over the Western Aleutians. An old stalled front
sits over the area while another weak system moves toward the
Western Aleutians from the south. This system will also be stalled
by the high pressure as it nears the islands. Out east over the
Eastern Aleutians and Alaska Peninsula, northerly flow will bring
showers to the Bering side of the islands and peninsula. The
showers will diminish early Wednesday as the main trough moving
through the area pushes off to the south.

&&

.LONG TERM FORECAST (Days 3 through 7)...
By the beginning of the extended forecast period (Friday) much
of the region will have already undergone a transition in the
overall pattern, with a broad upper level trough over much of the
Mainland and Gulf, and strong ridging out west over the Bering Sea
and Aleutians. This general setup will persist through early next
week, which will consist of colder air filtering down from the
arctic and strong outflow winds over parts of the Southern
Mainland. Models remain in good agreement with the overall pattern
into the weekend. As expected though, there is more uncertainty
with regards to the finer details, especially with respect to low
amplitude shortwave troughs diving south toward the Gulf of Alaska
coast Friday through Monday.

All three major global deterministic models, (the ECMWF, Canadian
GDPS, and GFS) along with their respective ensembles, are also
depicting a rather significant bora polar air outbreak across much
of Mainland Alaska. There is potential of seeing 850 hpa
temperatures reaching as low as -20C to -30C across the Southern
Mainland with cold offshore flow along the coast. The March sun
should moderate some of the cold air at the surface, but the
reality of this situation is it will be quite cold and well below
average for the next 7-9 days, dominated by dry offshore flow and
cold interior temperatures.

&&

.AFC WATCHES/WARNINGS/ADVISORIES...
PUBLIC...None.
MARINE...Heavy Freezing Spray Warning 121 126 127 129 130 136 137
138 139 141 150 160 165 180 185. Gale Warning 127 130 131 132 136
137 139 150 155 165 175 176 177 178 180.

&&

SYNOPSIS AND MODEL DISCUSSION...EN
SOUTHCENTRAL ALASKA...MTL
SOUTHWEST ALASKA/BERING SEA/ALEUTIANS...DK
LONG TERM...TP