January Weather Discussion: Slight Chance Severe Storms

[srainhoutx]

By hour 144, 1055mb high building in NW Territories. This run is colder. 0 degree 850's drapped along Coastal TX. Clouds showing up in the H7. Heights continue to build across AK. Weaker storm in the NW Pacific Coast.

[redneckweather]

1053mb high in northwestern Canada @ the end of day 7, hr162 that is.

[srainhoutx]

1053mb high in northwestern Canada @ the end of day 7, hr162 that is.

Cross Polar flow well established. Cyclone in Western Canada drawing in colder air (700mb) from Eurasia. 300mb winds very strong N to S over Polar region.

[srainhoutx]

By 180, our warm up begins. Heights continue to build NW AK. -EPO signals rather stout. Very cold air building across Western/Central Canada. Pacific NW Storm is inland into Western WA/ID.

[snowman65]

What's with all the tidbits of info being posted??

[redneckweather]

What's with all the tidbits of info being posted??

The latest 12z GFS model run.

[srainhoutx]

Longer range (252) 1058mb high in Western Canada. Second surge heading S as a deep storm forms in the Plains and heads NNE (Lakes Cutter). Cold air returns to the Lone Star State.

[wxman57]

Nothing extreme for us temperature-wise on the 12Z GFS:

[redneckweather]

It looks like the coldest day is Monday before the arctic air even gets established down here, according to the latest GFS. lol

[srainhoutx]

Looks like a good ingest with some minor issues...

Last Update: Thu Jan 6 16:45:01 2011 GMT
NWS TOC Operational Status Message
No current message

NCEP Operational Status Message
Thu Jan 6 14:56:45 2011 GMT
NOUS42 KWNO 061456
ADMNFD

SENIOR DUTY METEOROLOGIST NWS ADMINISTRATIVE MESSAGE
NWS NCEP CENTRAL OPERATIONS CAMP SPRINGS MD
1454Z THU JAN 06 2011
12Z NCEP MODEL PRODUCTION IS ON TIME. THE 12Z GFS
STARTED ON TIME WITH 32 CANADIAN...13 MEXICAN...AND
7 CARIBBEAN STATIONS AVAILABLE FOR INGEST.
12Z NAM RAOB RECAP...
FGZ/72376 - PURGED HEIGHTS/TEMPS/MOISTURE 789-784MB...TOO
COLD.
MEX/76679 - PURGED WINDS 776-728MB...TOO FAST.
ASY/70414 - 10145...UNFAVORABLE WEATHER CONDITIONS.
PPG/91765 - 10142...GROUND EQUIPMENT FAILURE.
NCC/78988 - 10142...GROUND EQUIPMENT FAILURE.
$$
KEMPISTY/SDM/NCO/NCEP

[srainhoutx]

I believe some folks follow Don Sutherland from S2k and Americanwx. Don is a friend and we chat frequently and just posted this...

The 12z GFS lent support to the idea of a period of brutal cold for the Pacific Northwest, Northern Plains, and then later East (preceded by a storm, and IMO that event may have more cutting potential than the possible 1/11-13 event). If the details are right--and it's still way out there--Ottawa Blizzard could even see the type of winter cold he cherishes (subzero fahrenheit maximum temperature for Ottawa). Some sharp cold will likely penetrate Texas.

[srainhoutx]

12Z Canadian (GEM) suggests a 1070mb high and front all the way S past Veracruz, MX. Also that model again suggests a convective bomb across TX this weekend.

[sleetstorm]

In my book, 30's and 20's- for highs and lows in the 20's and 10's- are what I consider to be true arctic air.

[BiggieSmalls]

In my book, 30's and 20's- for highs and lows in the 20's and 10's- are what I consider to be true arctic air.

Move to Dallas and you'd get it in a few days

[wxman57]

12Z GFS does predict highs in the mid 30s in Houston on Thursday. That's pretty cold. Cloudcover (or not) will be a big factor as far as how cold it gets at night. And we still have no cold air in Canada to follow...

[Andrew]

12Z Canadian (GEM) suggests a 1070mb high and front all the way S past Veracruz, MX. Also that model again suggests a convective bomb across TX this weekend.

Thats cold! I think the euro and the Canadian are on the right track. The GFS just looks impractical for a 1040 high down here. 12z should be interesting.

[ronyan]

The coldest reading I could find in Canada right now is -26F in Ennadai Lake, Nunavut. Not very impressive at this time.

[srainhoutx]

12Z Canadian (GEM) suggests a 1070mb high and front all the way S past Veracruz, MX. Also that model again suggests a convective bomb across TX this weekend.

Thats cold! I think the euro and the Canadian are on the right track. The GFS just looks impractical for a 1040 high down here. 12z should be interesting.

I know many folks discount the Canadian, but it does seem the Euro/Canadian have been handling things in the upper levels a bit better. We will see, though. As wxman57 states, we still do not yet 'see' the cold air spilling S. We'll likely not know that big detail until tomorrow into Saturday which makes things very challenging from a sensible forecasting stand point.

[wxman57]

I'd like to make a point about using predicted high pressure values to estimate potential cold down here. Often, very cold Arctic air will be so shallow that there really isn't a very strong high pressure center associated. In December 1989, the high center that crossed into the U.S. was about 1048mb. By the time it reached Arkansas it was down to 1035-1036mb. Now you'd not normally think of a 1035mb high over Arkansas as indicating it would be extremely cold here, but that cold airmass was quite shallow - and quite cold. We were below freezing in Houston for about 4 days, with a minimum of 7 degrees on one morning.

So don't focus TOO much on how many millibars the high center is. Instead, look at the actual cold airmass to estimate how cold it may get here. We can get pretty cold with only a moderately strong high center. It all depends on the character of the Arctic airmass.

[tireman4]

I'd like to make a point about using predicted high pressure values to estimate potential cold down here. Often, very cold Arctic air will be so shallow that there really isn't a very strong high pressure center associated. In December 1989, the high center that crossed into the U.S. was about 1048mb. By the time it reached Arkansas it was down to 1035-1036mb. Now you'd not normally think of a 1035mb high over Arkansas as indicating it would be extremely cold here, but that cold airmass was quite shallow - and quite cold. We were below freezing in Houston for about 4 days, with a minimum of 7 degrees on one morning.

So don't focus TOO much on how many millibars the high center is. Instead, look at the actual cold airmass to estimate how cold it may get here. We can get pretty cold with only a moderately strong high center. It all depends on the character of the Arctic airmass.

Thank you sir for that nugget of information. I, for one, sometimes get caught up in the hype of high pressure bombs ( like 1050 MB and up).