vci_guy2003 wrote:Can someone tell me what the long range models show? Temperature-wise?
It is way too soon to know the 'finer details' such as temperature we may see during the second week of December this far out, but the ensembles generally agree that a strong Arctic boundary will settle into the Western US and Great Basin next week that will plummet temps to 20+ below normal across the Pacific NW/Great Basin and Northern Rockies and a secondary surge of much colder air will drop S across Canada and settle into the Western 2/3rds of North America as far south as Mexico and points W of the Mississippi River Valley during the second week of December. There are rather strong indications that the coldest air of all the Northern Hemisphere will be located on our side of the world, so it will be worth monitoring. Happy Thanksgiving everyone from Srain's house to yours.
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I am becoming increasingly interested in the medium range for our Region as the operational and ensemble guidance continue to advertise a synoptic pattern favorable for moisture and anomalously cold air developing across the Pacific NW into the Great Basin/Northern Rockies extending into the Northern/Central Plains. The wild card will be just how much of a snow cover can be established across the Plains and the eventual storm tracks with an Arctic air mass firmly entrenched before a secondary surge of Arctic air pushes further E and S into the Southern Rockies and Southern Plains. As we have just witnessed, even a +AO that briefly dipped into slightly negative territory and a slightly +PNA can deliver some very chilly air very far S into Texas and Mexico, so it will be interesting to see if we see some MJO tropical forcing begin to interact with increased sub tropical jet moisture beyond the medium range time frame. It does appear that our source Regions will have abundant cold air to work with as well. All that is lacking appears to be snow cover across the Plains that would tend to guarantee less air mass modification during the second week of December.
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srainhoutx wrote:I am becoming increasingly interested in the medium range for our Region as the operational and ensemble guidance continue to advertise a synoptic pattern favorable for moisture and anomalously cold air developing across the Pacific NW into the Great Basin/Northern Rockies extending into the Northern/Central Plains. The wild card will be just how much of a snow cover can be established across the Plains and the eventual storm tracks with an Arctic air mass firmly entrenched before a secondary surge of Arctic air pushes further E and S into the Southern Rockies and Southern Plains. As we have just witnessed, even a +AO that briefly dipped into slightly negative territory and a slightly +PNA can deliver some very chilly air very far S into Texas and Mexico, so it will be interesting to see if we see some MJO tropical forcing begin to interact with increased sub tropical jet moisture beyond the medium range time frame. It does appear that our source Regions will have abundant cold air to work with as well. All that is lacking appears to be snow cover across the Plains that would tend to guarantee less air mass modification during the second week of December.
A negative East Pacific Oscillation (EPO) can give cold air even when NAO and AO are positive. The December 1983 and February 1989 Freeze occurred during a positive NAO and AO, but negative EPO. The February 1989 Freeze had a strong positive NAO and AO.
Being a lifelong student of meteorology is a great thing ... and all of us here sit in that classroom. Personally, I've learned a lot already this month about just how strongly the Pacific teleconnections impact our weather here in south central (and southeast) Texas. Even though the Arctic Oscillation (AO) and North Atlantic Oscillation (NAO) have been primarily positive -- which usually means warmer conditions -- the Eastern Pacific Oscillation (EPO) has overwhelmed those signals and that, combined with ridging in the North Pacific/Alaska, has helped keep us cold and stormy in the last two weeks.
The Madden-Julian Oscillation (MJO) looks to remain in the 8-1-2 octants which suggests colder than normal and wetter than normal conditions for Texas. The strength of the MJO signal doesn't appear too strong though so the MJO's impact may be minimal. I know enough about this stuff to be dangerous!
1983 was many days of freezing temps combined with drizzle. No snow fell except for, I believe Lakeview. Older brother and I were fired up when we watched the noon news before the cold air marched south.
It was a Christmas break I'll never forget. One for the freezing temps. Two for the letdown that all that cold left not one snowflake to be seen. Believe our heater also broke, which left us burning just about everything in the fireplace.
I'm not seeing anything like 1983 or 1989. Here's a plot of the 12Z GFS forecast temps (valid 6am and 6pm). Lows near freezing and a high in the 40 deg range next Sunday with some rain around. Very much like this week was. A quick warm-up on Tuesday followed by another cold front then another quick warm-up.
I see nothing in last night's GFS to indicate any frozen precip or very cold temps here through 15 days. I do see temps near 80 next week and then a light freeze next weekend (no precip).
Nice-looking meteograms, wxman57! I highly doubt they'll verify but nice-looking nevertheless.
No sir, one operational run of a somewhat poorly performing computer model will not save you from the coming winter apocalypse. Teleconnections and model ensembles point to a colder, stormier southeast Texas than what this shows.
Joe mentions 1983/1989 or 1899 every year. I started reading him back in 99/2000 and even back then, he would bring out the 'ghost of 1899' every time he saw cross polar flow being setup. The chances of us seeing such an extreme event in any given season is extremely low.
jasons wrote:Joe mentions 1983/1989 or 1899 every year. I started reading him back in 99/2000 and even back then, he would bring out the 'ghost of 1899' every time he saw cross polar flow being setup. The chances of us seeing such an extreme event in any given season is extremely low.
Oh, I totally agree Jason. We see people every winter roll out the 1983 or 1989 comparisons, or even the 1899 one. It's hyperbole. What we have seen though from the model analogs is suggestion that the pattern in the days ahead is similar to December 1983. People aren't just making it up ... the actual model analogs show that month/year along with comparisons to other periods where the weather patterns match closely.
I'm skeptical myself of an 83 or 89 redux ... but next weekend, a cold front -- similar to or slightly stronger than what we just saw -- is a very real possibility.
Belmer wrote:I was more talking about the 00Z GFS in whole, not specifically here in Houston.
I'm assuming you mean the portion of the 0z GFS operational run which showed two-thirds of Texas encased in snow and ice around the middle of December? Yes ... I'd say that is for amusement purposes only!
The 00Z GEFS anomalies suggest a lot of shades blue across a large potion of North America. There may well be a storm system tracking out of the Great Basin into the Plains as the Arctic boundary drops S into the Plains next weekend. There is already some 'chatter' to our N in Oklahoma and the Panhandle as well as New Mexico of more wintry mischief. I just do not see that air mass stopping at the Red River by a barbed wire fence as some of the operational guidance suggests.
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Portastorm wrote:Nice-looking meteograms, wxman57! I highly doubt they'll verify but nice-looking nevertheless.
No sir, one operational run of a somewhat poorly performing computer model will not save you from the coming winter apocalypse. Teleconnections and model ensembles point to a colder, stormier southeast Texas than what this shows.
I agree, that warming trend next week will probably continue through January.
My good friend, wxman57, I would like you to do a meteogram for IAH or AUS from the 12z GFS coming in now ... oh, let's look at temperatures starting around 12z on 12/9. Heh ... heh ...
It certainly appears that old stepping down pattern where each intrusion of colder air will be stronger than the one before. What raises an eyebrow is the amount of snow cover accumulating for a rather long period as multiple storm systems and abundant moisture spreads across the Plains meaning less air mass modification as time goes on.
EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
1059 AM EST FRI NOV 29 2013
VALID 12Z MON DEC 02 2013 - 12Z FRI DEC 06 2013
...BITTER COLD TO INVADE THE WESTERN HALF OF THE NATION THIS
FORECAST PERIOD...
...OVERVIEW...
ARCTIC SURGE AND AMPLIFYING UPPER-LEVEL FLOW FROM THE EASTERN
PACIFIC TO THE INTERMOUNTAIN WEST WILL BE THE PREVAILING WEATHER
THEMES THIS MEDIUM RANGE PACKAGE ACROSS THE WESTERN HALF OF THE
CONTINENTAL UNITED STATES. IN THE EAST AND SOUTHEAST...THE MAIN
FORECAST CHALLENGE WILL BE TO DETERMINE THE OUTCOME IN THE WESTERN
ATLANTIC--OF SOUTHERN STREAM ENERGY ORIGINATING IN SOUTHERN AND
BAJA CALIFORNIA.
...MODEL PREFERENCES AND UNCERTAINTY ASSESSMENT...
ASPECTS OF THE DETERMINISTIC 29/00Z GFS/ECMWF AND THEIR RESPECTIVE
MEANS SHOULD HANDLE THE LARGER-SCALE WEATHER FEATURES THIS MEDIUM
RANGE FORECAST PERIOD. THAT INCLUDES THE PROGRESSION OF A MASSIVE
AND BITTERLY-COLD ARCTIC INTRUSION INTO THE LOWER 48 ON LATE
MONDAY INTO TUESDAY.
THE BIGGEST FORECAST CHALLENGE IS TIMING THE SOUTHWARD RELEASE OF
THE AIRMASS THROUGH THE VERY COMPLEX TERRAIN OF THE ROCKIES AND
GREAT BASIN. TIED TO THIS RELEASE...A SERIES OF MID-LEVEL
SHORTWAVES WILL ROTATE THROUGH THE BASE OF THE BROAD-SCALE
UPPER-LEVEL TROUGH AND PROVIDE SOME OVER RUNNING MOISTURE THAT
WILL INITIALLY MODIFY THE LEADING EDGE OF THE BOUNDARY. THIS SETS
UP A LONG-DURATION WINTER WEATHER EVENT FOR A LARGE PORTION OF THE
WEST...INCLUDING MONTANA...IDAHO PORTIONS OF NORTHERN
UTAH-NORTHERN COLORADO...WYOMING AND THE DAKOTAS.
WPC MANUALLY ADJUSTED THE SURFACE GRAPHICS TO FIT TERRAIN AND
INCLUDED A 40+ MILLIBAR SURFACE GRADIENT BETWEEN NORTHWEST MONTANA
AND SOUTHWEST KANSAS FOR DAYS 4-5. THIS IMPLIES STRONG
WIND...COUPLED WITH SIGNIFICANT SNOWFALL.
ALOFT...THE GEFS...NAEFS AND ECMWF ENSEMBLE GUIDANCE PREFER TO
MAINTAIN A DEEP TROUGH AXIS OVER THE DESERT SOUTHWEST INVOF 110W
THROUGH THE END OF THIS MEDIUM RANGE PERIOD...BUT HAVE DIFFERENT
SOLUTIONS AND CONCLUSIONS DOWNSTREAM WITH AN 'INITIAL SHORTWAVE'
EXITING THE UPPER-LEVEL SYSTEM AS EARLY AS DAY 4 (INTO THE
NORTHERN HIGH PLAINS).
THE 29/00Z DETERMINISTIC CYCLE OFFERED A MIXED BAG OF
RESULTS...WITH THE 29/00Z CANADIAN BEGINNING TO TAKE A FASTER AND
MORE SOUTHERLY SOLUTION OVER THE PLAINS BY 4/00Z WITH THE ENERGY
TRACKING OVER THE BLACK HILLS AND QUICKLY RACING IT EASTWARD INTO
NEBRASKA/IOWA BY 4/18Z.
RECOMMEND A BLEND OF THE DETERMINISTIC 29/00Z ECMWF/GFS TO SORT
OUT SOME OF THE SMALLER SCALE DETAILS SURROUNDING THE DIGGING
UPPER-LEVEL TROUGH WHICH PEELS SLOWLY SOUTHWARD AND DRAW THE
ARCTIC AIRMASS WEST OF THE CONTINENTAL DIVIDE AND DEEP WITHIN THE
GREAT BASIN AND DESERT SOUTHWEST DURING THE LATTER HALF OF THIS
PACKAGE. BOTH HAVE A 'LEAD' SHORTWAVE EJECTING NORTHEASTWARD IN
THE DAKOTAS AROUND 5/12Z...BUT MAINTAIN THE BULK OF THE
ENERGY--AND MORE IMPORTANTLY--COLD POOL ALOFT OVER IDAHO (THE
ECMWF) AND EASTERN NEVADA (THE GFS) WHEN THE CANADIAN HAS THE LEAD
SHORTWAVE...AND MUCH OF THE UPPER-LEVEL TROUGH RACING TOWARDS
SOUTHERN ONTARIO.
...SENSIBLE WEATHER HIGHLIGHTS...
CONFIDENCE IS RISING FOR TEMPERATURES RANGING FROM 15F TO 25-30+ F
BELOW NORMAL ACROSS THE WESTERN STATES AND NORTHERN PLAINS.
VOJTESAK
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Portastorm wrote:My good friend, wxman57, I would like you to do a meteogram for IAH or AUS from the 12z GFS coming in now ... oh, let's look at temperatures starting around 12z on 12/9. Heh ... heh ...
Only 37 at 12Z on the 9th at IAH. 26-27 next 2 days but a quick warm-up.
