572 replies to this topic

[patrick7032]

Started this thread to see how many people would be interested as we approach the winter storm season where HURRICANE FORCE WIND WARNINGS are not all that uncommon. I have also noticed that when we get a seasonally deep 500mb low dropping southeast up here as it tends to eject into the lower 48 active weather usually follows with decent severe weather outbreaks .

[baroclinic_instability]

I am interested. I have been keeping up to date on weather up there lately, perhaps because of you and niumetgf, but also because of the extreme boredom of 600 dm subtropical death ridges.

[NIUmetGF]

I see the GFS is progging the return of the 0 degree 850mb isotherm to southern Alaska. Nobody wants to see termination dust around here yet!

[baroclinic_instability]

I see the GFS is progging the return of the 0 degree isotherm to southern Alaska. Nobody wants to see termination dust around here yet!

Termination dust?
I see some DCVA by CD3 progged by the EC/GFS for day 3.5+. Looks pinwheelish.

[patrick7032]

I see the GFS is progging the return of the 0 degree 850mb isotherm to southern Alaska. Nobody wants to see termination dust around here yet!

Yeah will post the data in a few....only have 256k speed here so may take a few to load images.

[patrick7032]

Some cool ACSL pics from 2 weeks ago....give it a few as internet is slow today.

[patrick7032]

Some cool ACSL pics from 2 weeks ago....give it a few as internet is slow today.

[baroclinic_instability]

Those are bada** mtn waves.

[patrick7032]

I see the GFS is progging the return of the 0 degree 850mb isotherm to southern Alaska. Nobody wants to see termination dust around here yet!

[beavis1729]

Thanks for starting this thread...good stuff.
I hope you're both enjoying life in Alaska.

[NIUmetGF]

Looks like the GFS has backed off the -2 to -4 C 850 mb temps it was outputting yesterday.

 850T.png   15.71K   1 downloads

Not surprising considering the ridging/warm 850 T's (+12 C extending up into the Beaufort Sea) to the northeast cutting it off from any reinforcing cold air and a warm southwest flow behind the north Pacific ridge. Strange to think of a system being "cut-off" when it is on the polar side of the jet. This type of a pattern seems to favor climatology with a mean trough centered over western Alaska and the Bering Strait. You can see the July/Aug mean 500mb geopotential height pattern isn't too far off from what is happening now.

climo
 500climo.png   13.12K   0 downloads

current
 gfs500mb.gif   940.95K   2 downloads

The major difference I see is the high latitude block over Greenland which has acted to shift the polar vortex toward the Chukchi/Beaufort Seas. This developing pattern is depicted well in the ensemble mean forecasts of several teleconnectors....

 pna.png   12.99K   1 downloads

The progged positive PNA makes sense with the deepening low and embedded disturbances moving south into the Bering Sea will act to build the heights downstream over the intermountain west though I think the + phase is more related to the negative height anomalies over the Aleutians.

 NAO.png   12.6K   0 downloads

The negative NAO at the same times shows the developing positive height anomolies over Greenland.

 500current.gif   178.84K   0 downloads

All of these factors make for a cooler wetter period for southern Alaska. I am no teleconnector guru by any means, but just my take on the current pattern.

[patrick7032]

Thanks for starting this thread...good stuff.I hope you're both enjoying life in Alaska.

Thanks Beavis....I expect this thread will get a lot busier once the winter storms hit and we get HURRICANE FORCE WIND WARNINGS with 60+kt sustained zone forecasts with seas 30 feet plus. Until then will try to post few times a week with met data.

[patrick7032]

Looks like the GFS has backed off the -2 to -4 C 850 mb temps it was outputting yesterday.

 850T.png   15.71K   1 downloads

Not surprising considering the ridging/warm 850 T's (+12 C extending up into the Beaufort Sea) to the northeast cutting it off from any reinforcing cold air and a warm southwest flow behind the north Pacific ridge. Strange to think of a system being "cut-off" when it is on the polar side of the jet. This type of a pattern seems to favor climatology with a mean trough centered over western Alaska and the Bering Strait. You can see the July/Aug mean 500mb geopotential height pattern isn't too far off from what is happening now.

climo
 500climo.png   13.12K   0 downloads

current
 gfs500mb.gif   940.95K   2 downloads

The major difference I see is the high latitude block over Greenland which has acted to shift the polar vortex toward the Chukchi/Beaufort Seas. This developing pattern is depicted well in the ensemble mean forecasts of several teleconnectors....

 pna.png   12.99K   1 downloads

The progged positive PNA makes sense with the deepening low and embedded disturbances moving south into the Bering Sea will act to build the heights downstream over the intermountain west though I think the + phase is more related to the negative height anomalies over the Aleutians.

 NAO.png   12.6K   0 downloads

The negative NAO at the same times shows the developing positive height anomolies over Greenland.

 500current.gif   178.84K   0 downloads

All of these factors make for a cooler wetter period for southern Alaska. I am no teleconnector guru by any means, but just my take on the current pattern.

Yeah we even had a few sunny days this week and looks like a few more next week. Talk about a nice short wave ridge (see images). Will be interesting to see if one of these 500 lows head SE to the lower 48.

[NIUmetGF]

A moist southwest flow and compact potential vorticity anomaly is continuing a climatologically wet pattern to south central Alaska today. The dynamic tropopause (1.5 PVU surface) extends down to almost 550 mb with the stratospheric intrusion bringing some very dry air close to -80 C dew point. Doesn't look like much at first glance.

 AK-ETA12_PV15_Pressure_20110809_1200F006.png   334.6K   0 downloads

Doing some QC on the incoming data I figured I had a faulty hygristor when I first saw the dew point tank. After looking at the upstream sounding from Bethel (PABE) from 00z and the recent 12Z it appears as if it is good data.

Aug 9th 12Z for Anchorage (PAFC) and Bethel (PABE)

 PAKN_20110809_1200.png   42.86K   0 downloads

[NIUmetGF]

http://www.nasa.gov/...k-AIRS_full.jpg

In other news, the remains of Merbok are giving the models fits in the long range forecast

[baroclinic_instability]

A moist southwest flow and compact potential vorticity anomaly is continuing a climatologically wet pattern to south central Alaska today. The dynamic tropopause (1.5 PVU surface) extends down to almost 550 mb with the stratospheric intrusion bringing some very dry air close to -80 C dew point. Doesn't look like much at first glance.

 AK-ETA12_PV15_Pressure_20110809_1200F006.png   334.6K   0 downloads

Doing some QC on the incoming data I figured I had a faulty hygristor when I first saw the dew point tank. After looking at the upstream sounding from Bethel (PABE) from 00z and the recent 12Z it appears as if it is good data.

Aug 9th 12Z for Anchorage (PAFC) and Bethel (PABE)

 PAKN_20110809_1200.png   42.86K   0 downloads

Nice maps. Got to love our awesome hygristors. Nice catch though, looks legit, and it makes sense with that type of deep tropopause that stratospheric mixing is occurring.

[patrick7032]

For those of you that wonder if tornadoes occur in Alaska, yup they do. This location is in my zone and have been told by the locals that funnels occur at times in Cold Bay. It's also amazing how high the surge can get if the earthquake occurs "in the right spot". These images were taken from material I'm reviewing which I received from co-workers.

[patrick7032]

For those of you that wonder if tornadoes occur in Alaska, yup they do. This location is in my zone and have been told by the locals that funnels occur at times in Cold Bay. It's also amazing how high the surge can get if the earthquake occurs "in the right spot". These images were taken from material I'm reviewing which I received from co-workers.

[patrick7032]

Nice story about the Glacial Flood in Juneau last month with other stories linked to the page. I know someone at regional who has great photos of the event which I will post later.

http://juneauempire....ocal/2011-07-21

[patrick7032]

Nice 589dm ridge building into the Aleutians with a deepening trough in the Gulf of Alaska heading southeast.

[patrick7032]

Nice 589dm ridge building into the Aleutians with a deepening trough in the Gulf of Alaska heading southeast.

[AK_weather]

Termination dust?
I see some DCVA by CD3 progged by the EC/GFS for day 3.5+. Looks pinwheelish.

Termination dust is the Alaskan term which describes the first snow to fall on the peaks of the mountains outside of town and which actually sticks for good. It signals the last days of summer before the long Anchorage winter.

[NIUmetGF]

Termination dust is the Alaskan term which describes the first snow to fall on the peaks of the mountains outside of town and which actually sticks for good. It signals the last days of summer before the long Anchorage winter.

Is this C.C.?

[Hal]

Nunavut is missing off all those posted weather maps, just saying

[AK_weather]

a

Is this C.C.?

Yes.

[mnchaser]

Termination dust is the Alaskan term which describes the first snow to fall on the peaks of the mountains outside of town and which actually sticks for good. It signals the last days of summer before the long Anchorage winter.

Anchorage, AK doesn't even seem like it has that bad of a winter historically speaking..Not any worst then say a place like Duluth,MN.

[AK_weather]

Anchorage, AK doesn't even seem like it has that bad of a winter historically speaking..Not any worst then say a place like Duluth,MN.

Winters are milder than places in the Upper Midwest but also much longer. Anchorage's climate is much milder than locations just a few miles away in the southern interior. Sitting on a broad peninsula that juts out into Cook Inlet certainly has an advantageous effect. It is also rather dark most of the day, with November and December usually featuring overcast skies so that even when there is daylight, it is still rather gloomy. The white of frequent fresh snowfalls from mid-November through late December does mitigate a lot of the darkness though.

[patrick7032]

SXAK78 PACD 121156
RERCDB

RECORD EVENT REPORT
NATIONAL WEATHER SERVICE COLD BAY AK
356 AM AKDT FRI AUG 12 2011


...RECORD HIGH TEMPERATURE SET...

AT 4:59 PM AKDT THE TEMPERATURE AT THE STATE AIRPORT AT COLD BAY REACHED
67 DEGREES. THIS BREAKS THE RECORD OF 65 DEGREES SET IN 2001.

$$
JAP AUG 11



Believe we were close to a record during Friday too....I'm checking on this now....when I flew out to Anchorage Thursday it was definitely "toasty"....which 67 doesn't sound like much to people back in the lower 48, and sure there is acclimation involved, but with the high sun angle that felt like 77....could take another day or to like that....

[NIUmetGF]

Rather than make a long post here, I blogged about some local terrain effects. I struggled with going between technical/non-technical for non-met types so it's kind of in a grey area in between.

http://mtlawsonwx.wo...cts-of-terrain/

[baroclinic_instability]

Rather than make a long post here, I blogged about some local terrain effects. I struggled with going between technical/non-technical for non-met types so it's kind of in a grey area in between.

http://mtlawsonwx.wo...cts-of-terrain/

Nice post. Interesting features that stick out in the PABE sounding is the strong above mountain top inversion (around 850 hpa) which probably enhanced the trapped wave mode, but probably too high to incite strong downslope winds given the height of the range. I am assuming no major downslope winds?

The other interesting feature is the model cross section which seems to be simulating a vertically propagating mode given the back tilt of the wave w/height. Do you guys have any higher res x-sections? I found the x-section tropopause uniquely flat...also neat to see how the model simulates (actually probably parameterizes) the dampening of the wave as it reaches the tropopause.

[NIUmetGF]

Nice post. Interesting features that stick out in the PABE sounding is the strong above mountain top inversion (around 850 hpa) which probably enhanced the trapped wave mode, but probably too high to incite strong downslope winds given the height of the range. I am assuming no major downslope winds?

The other interesting feature is the model cross section which seems to be simulating a vertically propagating mode given the back tilt of the wave w/height. Do you guys have any higher res x-sections? I found the x-section tropopause uniquely flat...also neat to see how the model simulates (actually probably parameterizes) the dampening of the wave as it reaches the tropopause.

I was going to delve into vertically propagating mountain wave since one did develop later in the evening in this particular case but kept this post relatively short. You are right, no strong downslope winds developed, in fact the winds in Dillingham were even westerly off of Bristol bay in the afternoon and seemed almost decoupled from the flow aloft though this wasn't the case. I'll see if I can find a situation with our local wrf though I hear sometimes wrf can get alittle mountain wave happy.

[patrick7032]

SXAK78 PACD 171245
RERCDB

RECORD EVENT REPORT
NATIONAL WEATHER SERVICE COLD BAY AK
445 AM AKDT WED AUG 17 2011

RECORD TEMPERATURE OF 68F WAS SET ON AUGUST 16, 2011. THE OLD RECORD
WAS 65F SET IN 1984.

$$
*** AUG 11

[patrick7032]

A nice mid level trough will develop by early next week....if this verifies on SFC temp some areas along the western areas along the coast or in the chain may approach near record low max temps....if it verifies.

[patrick7032]

Definitely been a warm 8 days in the Aleutian Island chain as that ridge built over us. A few obs are below along with a weather summary so far. The records are highlighted in red and near records in pink.

Cold Bay:
PACD 170053Z 18015KT 10SM FEW025 SCT140 SCT250 19/13 A2983 RMK AO2 SLP103 BCFG DSNT NW-N ALONG THE BERING SEA COAST T01940128

PACD 172253Z 17019KT 10SM FEW006 BKN016 BKN060 BKN130 17/14 A2979 RMK AO2 DZB19E25 SLP087 CIG LWR S-SW P0000 T01670144 $

King Cove:
PAVC 162356Z AUTO 11013KT 10SM CLR 18/13 A2987 RMK AO2 TSNO 58002 T01770133 10177 20144 SLP116 $

Port Heiden:
PAPH 172136Z AUTO 01006KT 10SM CLR 19/11 A2986 RMK AO1 PNO

PAPH 162356Z AUTO 34013KT 10SM CLR 18/09 A2989 RMK AO1 10180 20100 401800030 57010 PNO

False Pass:
PAKF 170101Z AUTO 18008KT 10SM OVC026 17/13 A2985 RMK AO2 SLPNO T01670133

Dutch Harbor:
PADU 172258Z 20006KT 10SM FEW008 BKN050 21/14 A2973 RMK AO2 SLP074 BP T02060144

[patrick7032]

Definitely been a warm 8 days in the Aleutian Island chain as that ridge built over us. A few obs are below along with a weather summary so far. The records are highlighted in red and near records in pink.

Cold Bay:
PACD 170053Z 18015KT 10SM FEW025 SCT140 SCT250 19/13 A2983 RMK AO2 SLP103 BCFG DSNT NW-N ALONG THE BERING SEA COAST T01940128

PACD 172253Z 17019KT 10SM FEW006 BKN016 BKN060 BKN130 17/14 A2979 RMK AO2 DZB19E25 SLP087 CIG LWR S-SW P0000 T01670144 $

King Cove:
PAVC 162356Z AUTO 11013KT 10SM CLR 18/13 A2987 RMK AO2 TSNO 58002 T01770133 10177 20144 SLP116 $

Port Heiden:
PAPH 172136Z AUTO 01006KT 10SM CLR 19/11 A2986 RMK AO1 PNO

PAPH 162356Z AUTO 34013KT 10SM CLR 18/09 A2989 RMK AO1 10180 20100 401800030 57010 PNO

False Pass:
PAKF 170101Z AUTO 18008KT 10SM OVC026 17/13 A2985 RMK AO2 SLPNO T01670133

Dutch Harbor:
PADU 172258Z 20006KT 10SM FEW008 BKN050 21/14 A2973 RMK AO2 SLP074 BP T02060144