January: Seasonal Temps To End The Month

[jeff]

Thanks, Srain. Much appreciated. I was wondering about frozen precip this far to the east of you guys.

The air mass over Louisiana appears much more saturated than over TX which allows little room for cooling behind the front. Raw GFS output for Lake Charles shows temperatures in the 40's on Wed/Thurs with dewpoints in the mid to upper 30's so not much room for any cooling and expect the freezing line will be well back WNW over C TX. Looking like a cold rain....for Louisiana at least the southern 1/2 half of the state.

[harpman]

Not what I was hoping for, Jeff, but thanks for the response!

[don]

0z Euro shows a possible major winter storm late next week for the southern half of the state..... Looking how consistent the euro and Canadian models have been im effeminately starting to feel more confidence but time will tell...

[Belmer]

0z Euro shows a possible major winter storm late next week for the southern half of the state..... Looking how consistent the euro and Canadian models have been im effeminately starting to feel more confidence but time will tell...

Just looked at 0z Euro and Candian runs, they do raise an eyebrow for areas out west and south. We'll have to keep monitoring it, especially this weekend. Just like last weeks Christmas storm, Sunday we'll know a lot more, but this will be one of those storms we'll have to watch as it happens. Of course, it seems like all possible winter storm threats are like that for us here in Texas.
And of course, now that I'm home for winter break, it would snow in San Marcos. Depressing....

As far as this being a major winter storm threat, that is too early to tell as well. By model runs this evening, nothing too big/serious. An inch of snow out towards San Antonio/Austin and some solid rain for us here in SE TX. Of course, this would be major on the fact that nobody in Texas can drive in winter weather. Then yes, this will be catastrophic.

[Andrew]

The GFS versus the CMC and EURO shows a sheared out system and the second of a series of shortwaves/ cutoff lows that approaches from the Rockies. The GFS is tuning in with the slower progression but shears out the second low completely which presents a really dry profile for most of the state. The front is stalled just off the coast which provides some moisture right on the coast/ barely inland but nowhere near any type of freezing. The Euro and CMC both show a very slow progression of systems coming from the NW. The first system on New Years eve/day will provide showers and storms around the area (SE Houston) but around the 3-4th the second piece of energy arrives according to the Euro and CMC but is not nearly as sheared and provides more moisture. A lot of questions remain unanswered and we still seem to have a split group between the models.

Looking a little longer into the forecast period Srain and I were talking about the Euro and GFS showing a Major Stratospheric Warming Event which could throw some kinks into the middle of the month. The Euro shows around a 40C increase in temps and a wind reversal. Something to keep an eye on for later in the month.


PS LOOK AT THE TIME DIFFERENCES FOR THE MODELS:

[Andrew]

0z Euro shows a possible major winter storm late next week for the southern half of the state..... Looking how consistent the euro and Canadian models have been im effeminately starting to feel more confidence but time will tell...

Just looked at 0z Euro and Candian runs, they do raise an eyebrow for areas out west and south. We'll have to keep monitoring it, especially this weekend. Just like last weeks Christmas storm, Sunday we'll know a lot more, but this will be one of those storms we'll have to watch as it happens. Of course, it seems like all possible winter storm threats are like that for us here in Texas.
And of course, now that I'm home for winter break, it would snow in San Marcos. Depressing....

As far as this being a major winter storm threat, that is too early to tell as well. By model runs this evening, nothing too big/serious. An inch of snow out towards San Antonio/Austin and some solid rain for us here in SE TX. Of course, this would be major on the fact that nobody in Texas can drive in winter weather. Then yes, this will be catastrophic.

Well IF we did have a winter event the vertical profile would support an ice type of event. Overrunning of moisture would cause many issues if this does come true. Like you said though too early to tell.

[C2G]

Keep any icy forecast away from the Houston Metro area. Snow's nice, ice isn't.
When did we have our last little ice event, February 2011? Anyway, that was forecast to be a nice snow event, but a warm layer busted that forecast.
Have they garnered anymore upper air obs for our area when compared to 2011? That could tell forecasters those all important temperatures aloft. That seems very important for accurate forecasting, especially for southeast Texas. And, I'll be somewhat skeptical of any snow forecast otherwise.

As you saw yesterday, it's difficult to predict winter weather types/amounts here without good data of air temps aloft. We just have no upper air obs anywhere near Houston, so the models don't know what is really happening aloft as far as temps. We cannot even predict precip type a few hours out much less next Wednesday. It does look cold though, and there could be precip involved.

[srainhoutx]

Keep any icy forecast away from the Houston Metro area. Snow's nice, ice isn't.
When did we have our last little ice event, February 2011? Anyway, that was forecast to be a nice snow event, but a warm layer busted that forecast.
Have they garnered anymore upper air obs for our area when compared to 2011? That could tell forecasters those all important temperatures aloft. That seems very important for accurate forecasting, especially for southeast Texas. And, I'll be somewhat skeptical of any snow forecast otherwise.

As you saw yesterday, it's difficult to predict winter weather types/amounts here without good data of air temps aloft. We just have no upper air obs anywhere near Houston, so the models don't know what is really happening aloft as far as temps. We cannot even predict precip type a few hours out much less next Wednesday. It does look cold though, and there could be precip involved.

I agree with you Cloud2ground. The mere mention of the "s" word brings back vivid memories of busted forecasts and well...ice...that is certainly not what we want anywhere across the Region. We can't even travel around on a rainy day without accidents much less an Ice Storm. What does raise an eyebrow is the consistency being shown via the ensembles and the non American guidance that a more S into Northern Mexico track and a slowly progressing upper trough with embedded short waves rounding the base of that deep trough tapping into the Sub Tropic Jet with plentiful moisture streaming in from the Eastern Pacific. That is a classic winter weather recipe for an over running event and with the hints of waves of low pressure developing along a quasi stationary frontal boundary along the Coast down near the Rio Grande Valley and ripples of the waves riding ENE along that boundary. Past experience tells us it may be time to monitor things a bit closer. The trough continues to dig S along the California Coast this morning and this will be our New Years Eve rain/storm maker and bring the Canadian front through Texas on New Years Day. The second in a series of short waves is nearing British Colombia in Western Canada and will enter the RAOB (balloon radiosonde) network later tonight into tomorrow. That is what we will have to watch a bit more closely as it is that feature that is causing all the concern and chatter about closing off S of the Great Basin where a Ridge of High Pressure will be entrenched. I will say that what concerns me most is any potential ice threat we may have. It has been many years since we have seen a significant ice event across Southern half of Texas. With all the dead trees from the drought of last year and a couple of widespread high wide event this month, we have seen we have some real problems with these dead trees and Pines and Ice do not mix. I see the HPC is monitoring as well as NWS Houston/Galveston lending to credence to the Euro/Canadian ideas of a slower progressing, further S potential as well. Stay Tuned! This is a very low confidence forecast and things will change daily.



HPC:

EXTENDED FORECAST DISCUSSION
NWS HYDROMETEOROLOGICAL PREDICTION CENTER COLLEGE PARK MD
120 AM EST SAT DEC 29 2012

VALID 12Z TUE JAN 01 2013 - 12Z SAT JAN 05 2013


...2013 TO START OFF 'COLD' ACROSS MUCH OF THE UNITED STATES...

ALONG THE WEST COAST...2 SYSTEMS TRACK SOUTH-SOUTHEASTWARD INTO
CALIFORNIA IN THE MEDIUM RANGE FORECAST PERIOD THEN MIGRATE
THROUGH THE SOUTHERN ROCKIES AND MIDDLE RIO GRANDE IN THE SOUTHERN
STREAM. TO MAINTAIN SOME CONTINUITY WITH THE PREVIOUS PROGS...USED
PIECES OF THE 28/12Z CANADIAN AND ECMWF RUNS. NOT MUCH OF THE
28/12Z & 29/00Z GFS COULD BE USED IN THE MEDIUM RANGE
GRAPHICS...INCLUDING THE MORE PROGRESSIVE...FASTER...AND FLATTER
GEFS MEANS.

THE PREVIOUS 2 RUNS OF THE CANADIAN (28/00Z & 28/12Z) WOULD BE
AGGRESSIVE SOLUTIONS ON DAY 3 ACROSS CALIFORNIA VS THE 28/18Z GEFS
MEAN...28/12Z ECMWF MEANS AND PREVIOUS 2 RUNS OF THE OPERATIONAL
ECMWF (28/00Z & 28/12Z). INTERESTINGLY...THE TREND OF THE
OPERATIONAL CANADIAN/ECMWF IS MORE OF AN OFFSHORE TRACK...WEST AND
SOUTH OF PT CONCEPCION. AND SLOWER. IN FACT...BOTH OF THESE
OPERATIONAL RUNS ARE SLOWER THAN THEIR CORRESPONDING ENSEMBLE
MEANS EVEN INTO DAY 4.

DAYS 4-5....THE CANADIAN CONTINUES TO BE THE AGGRESSIVE SOLUTION
IN THE NORTHERN GULF OF CALIFORNIA WITH ITS CLOSED H5 SOLUTION.
WITH THE 28/12Z CANADIAN AND ECMWF OPERATIONAL RUNS OFFERING
DECENT DETAILS WITH THIS SOUTHERN STREAM SYSTEM TIL DAY5...BEGAN
BLENDING IN THE 28/12Z ECMWF ENSEMBLE MEAN IN THE EAST
PACIFIC/WEST COAST TO OFFSET THE VERY SLOW 28/12Z CANADIAN
SOLUTION ALONG 130W. IN FACT...THE 28/12Z CANADIAN ENSEMBLE MEANS
LOOK TO BE SLOW OUTLIER IN THE NORTHERN PACIFIC DAY 5 VS THE
28/18Z GEFS MEAN AND 28/12Z ECMWF MEANS. THIS POSED A PROBLEM
AND/OR CHALLENGE INTO DAY 7 FOR MAINTAINING CONTINUITY...WOULD
MAKE THE OPERATIONAL CANADIAN THE PREFERRED SOLUTION. SEEMED OUT
OF PLACE FOR DAYS 6-7 ALTOGETHER FROM DATELINE TO 100W (CENTRAL
CONUS/PLAINS) .

ACROSS THE GREAT BASIN...INTERMOUNTAIN WEST AND THE ROCKIES...NOT
A TON OF CHANGES IN THE NEW PROGS. THE UPPER-LEVEL RIDGE
ESSENTIALLY HOLDS FIRM THROUGH DAY 7. WHAT EROSION THAT DOES OCCUR
LOOKS TO BE IN THE DAY 5-6 TIME FRAME WITH THE 2ND WEST COAST
SYSTEM SPLITTING AND TRACKING SOUTHEASTWARD. ENERGY MOVING ATOP
THE RIDGE AXIS AND INTO SOUTH CENTRAL BRITISH COLUMBIA QUICKLY
TRACKS EAST INTO THE DAKOTAS. THE LAST TWO RUNS OF THE ECMWF ARE
VERY COLD ACROSS THE GREAT BASIN AND COLORADO RIVER BASIN...WITH
SUB-ZERO READINGS IN NORTHERN NEVADA...PARTS OF WYOMING AND
COLORADO. NEAR TO BELOW FREEZING TEMPERATURES WERE AS FAR SOUTH AS
LAS VEGAS AND PHOENIX BY DAY 4-5!!!

FEW ADJUSTMENTS WERE NEEDED DOWNSTREAM IN THE CONFLUENT FLOW
ACROSS THE MIDWEST...GREAT LAKES AND POINTS EASTWARD TO THE
WESTERN ATLANTIC SHORELINE AND GULF COAST. MANUAL SFC/H5 GRAPHICS
BLENDED THE PREVIOUS 2 ECMWF RUNS FOR FINER DETAILS IN TANDEM WITH
THE 28/12Z ECMWF ENSEMBLE MEANS TO TRACK A PROCESSION OF CANADIAN
FRONTAL BOUNDARIES TRACKING THROUGH THE EAST AND SOUTHEAST. THE
NORTHERN GULF COAST AND EASTERN SHORES OF THE CAROLINAS WILL BE
THE WETTER AREAS OF THE COUNTRY TO START OFF THE NEW YEAR.

VOJTESAK



NWS Houston/Galveston:

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HOUSTON/GALVESTON TX
444 AM CST SAT DEC 29 2012

.DISCUSSION...
IN THE SHORT TERM FORECAST LOOKS GOOD WITH HIGH PRESSURE OVER THE
AREA AND CIRRUS. TEMPERATURES WILL STILL BE ON THE COOL SIDE TODAY
WITH HIGHS ONLY STRUGGLING INTO THE LOWER TO MID 50S. THE HIGH
MOVES EAST ON SUNDAY AND EASTERLY FLOW SETS UP WITH A WARM FRONT
MOVING INTO THE COASTAL WATERS LATE IN THE AFTERNOON AND INTO THE
COASTAL COUNTIES MONDAY MORNING. THIS SHOULD LEAD TO LOW
CLOUDS/FOG/LIGHT RAIN WITH THE WARM FRONT GOING STATIONARY. THE
UPPER TROUGH OVER THE 4 CORNERS MONDAY MORNING STARTS TO MOVE EAST
THROUGHOUT THE DAY WITH MODERATE TO STRONG ISENTROPIC UPGLIDE
EXPECTING LIGHT RAIN THEN AS THE PROFILE DESTABILIZES MONDAY
AFTERNOON THE THREAT OF DEEPER CONVECTION DEVELOPS AND EXPECT TO
SEE SHOWERS AND THUNDERSTORMS. STILL EARLY BUT SPC HAS A SEE TEXT
IN PLACE FOR THE COASTAL AREAS AND MAY HAVE SOME BRIEF HEAVY
DOWNPOURS WITH A MODERATE LLJ. COLD FRONT MOVES THROUGH THE REGION
AND INTO THE GULF SLOWING DOWN AND GOING QUASI-STATIONARY
TUESDAY-THURSDAY. MODELS DIVERGING IN THE SOLUTIONS ON WEDNESDAY
WITH ANOTHER STRONG S/W DROPPING INTO THE WEST SIDE OF THE UPPER
TOUGH TO THE WEST...ECMWF IS DEEPER AND MUCH FURTHER SOUTH OVER
SOUTHERN BAJA AND THE GFS IF MORE PROGRESSIVE/NOT AS DEEP AND OVER
WEST TEXAS. EXPECT THAT THE GULF WATERS WILL SEE PLENTY OF UPGLIDE
-RA CLOUDS EXTENDING NORTH AND NORTHEAST OVER THE CWA HELPING TO
KEEP THE AREA COOLER DURING THE DAYTIME AND WARMER AT NIGHT...RAIN
CHANCES HIGHER NEAR THE COAST AND LOW OVER THE NORTH. GOING INTO
THURSDAY THE FORECAST GETS MORE INTERESTING WITH THE COLD AIR IN
PLACE PER THE ECMWF AND A RAPIDLY SATURATING COLUMN THE
POSSIBILITY OF SNOW MAY ARISE FOR THE NORTHWESTERN CWA...GFS IS
WARMER AND MUCH DRIER. NOT QUITE WILLING TO BITE OFF ON THE GFS
YET SO WILL KEEP A SLIGHT CHANCE/CHANCE OF RAIN GOING IN THE
FORECAST BUT IT COULD BUST BIG BOTH WAYS AT THIS POINT GIVEN THE
LOW CONFIDENCE. STAY TUNED.

[harpman]

The GFS versus the CMC and EURO shows a sheared out system and the second of a series of shortwaves/ cutoff lows that approaches from the Rockies. The GFS is tuning in with the slower progression but shears out the second low completely which presents a really dry profile for most of the state. The front is stalled just off the coast which provides some moisture right on the coast/ barely inland but nowhere near any type of freezing. The Euro and CMC both show a very slow progression of systems coming from the NW. The first system on New Years eve/day will provide showers and storms around the area (SE Houston) but around the 3-4th the second piece of energy arrives according to the Euro and CMC but is not nearly as sheared and provides more moisture. A lot of questions remain unanswered and we still seem to have a split group between the models.

Looking a little longer into the forecast period Srain and I were talking about the Euro and GFS showing a Major Stratospheric Warming Event which could throw some kinks into the middle of the month. The Euro shows around a 40C increase in temps and a wind reversal. Something to keep an eye on for later in the month.


PS LOOK AT THE TIME DIFFERENCES FOR THE MODELS:

Andrew, could you explain what the stratospheric warming event would mean? Thanks!

[txsnowmaker]

A snippet from this morning's Houston/Galveston National Weather Service update:

GOING INTO THURSDAY THE FORECAST GETS MORE INTERESTING WITH THE COLD AIR IN PLACE PER THE ECMWF AND A RAPIDLY SATURATING COLUMN THE POSSIBILITY OF SNOW MAY ARISE FOR THE NORTHWESTERN CWA.

(Source: http://forecast.weather.gov/product.php ... glossary=1)

It's been a LONG time since we have seen the HGX office even mention the word snow five days out. If they are already talking about the Northwestern portion of the HGX area, if this pans out, perhaps by the time Thursday comes around all of us will have a chance to get in on some of the action.

I can only imagine how many pages this thread will end up with if the other models end up converging around this scenario.

[txsnowmaker]

12z GFS is no longer on the "drier" side for our area during the time frame drawing interest. Things are getting interesting.

[Portastorm]

The GFS versus the CMC and EURO shows a sheared out system and the second of a series of shortwaves/ cutoff lows that approaches from the Rockies. The GFS is tuning in with the slower progression but shears out the second low completely which presents a really dry profile for most of the state. The front is stalled just off the coast which provides some moisture right on the coast/ barely inland but nowhere near any type of freezing. The Euro and CMC both show a very slow progression of systems coming from the NW. The first system on New Years eve/day will provide showers and storms around the area (SE Houston) but around the 3-4th the second piece of energy arrives according to the Euro and CMC but is not nearly as sheared and provides more moisture. A lot of questions remain unanswered and we still seem to have a split group between the models.

Looking a little longer into the forecast period Srain and I were talking about the Euro and GFS showing a Major Stratospheric Warming Event which could throw some kinks into the middle of the month. The Euro shows around a 40C increase in temps and a wind reversal. Something to keep an eye on for later in the month.


PS LOOK AT THE TIME DIFFERENCES FOR THE MODELS:

I'm not Andrew ... nor do I play him on television. Not smart enough. But that being said, the short answer is when people in North America are getting excited about a major stratospheric warming event, it has the ultimate effect of helping establish a high pressure block in Canada and often push Arctic air into the lower 48. These "events" are often the precursors to what we call Arctic outbreaks.

Andrew, could you explain what the stratospheric warming event would mean? Thanks!

[harpman]

Thank you, portastorm, for the reply. I thought that's what it was, but I wan't sure. Let's hope January is fun for all of us along the Gulf coast.

[weatherguy425]

Well the 12z GFS looks more believable. Good snows for New Mexico and some in west Texas. Lots of rain for coastal Texas as well. Hopefully is the beginning if a trend.

For the SSW event, also interesting to note the tanking of NAO/AO around the same time frame shown off and on for the past couple if days.

[srainhoutx]

The 12Z Canadian is out to hour 120 and suggest a fairly deep trough across Northern Mexico as precip breaks out across New Mexico and Texas. The stationary frontal boundary appears to be just off shore at that hour via the Canadian as a Coastal low develops in the Rio Grande Valley off shore of Brownsville.

Hour 96:

Hour 102:

Hour 108:

Hour 114:

Hour 120:

[srainhoutx]

The GEFS (GFS Ensemble Mean) continue to trend toward what the Euro and GGEM have suggested with a deep trough developing S of Arizona in Northern Mexico that slowly translates E during the Wednesday/Thursday time frame. The GEFS means also suggest fairly significant over running as a waves of low pressure ride along the quasi stationary Canadian frontal boundary off shore and several upper air disturbances rotate beneath the trough to our W and plentiful sub tropical moisture available as well.

500mb Anomaly:

850mb Temp Anomaly:

The attachment 12292012 12Z GEFS 12zgfsensembles850mbTAnomalyNA096.gif is no longer available

850mb Surface Pressures/Precip:

[Portastorm]

The 12z European operational run remains on board as well for a wintry weather episode in central, southeast, and south Texas later next week.

http://www.meteo.psu.edu/~fxg1/ECMWF_12z/ecmwfloop.html

[weatherguy425]

Another good trend for us west Texas folks.... more moisture is allowed to advect further inland as lift from any one of these multiple disturbances could allow for at least several periods of flurries this far north. Unless the air mass is more dense than modeled and the front moves further offshore.

[Andrew]

As others have noted, the GFS is coming around to the other models with less shearing for the second of a series of shortwaves. While the Second piece of energy is farther to the north compared to other models it is less sheared and slower.

Looking at the Sudden Stratospheric Warming (SSW) this event is when you have the polar vortex slow down and change directions which allows for a rise of stratospheric temperature. As a result colder air is allowed to filter south. If you look over in Siberia and China they are currently having record cold and that should begin to shift in our direction. This is something that will be discussed more once we get closer to it effecting us.

The Euro is remaining wet with the 12z run. This run is a little bit faster but still shows a very moist 850mb and 700mb profile with RH getting close to 100%. While the 850mb freezing line gets close to SE Texas the 1000-500mb critical thickness line stays in North Texas. Something to watch as we get closer. More to watch as we get closer.

[Portastorm]

Thanks for the info, Andrew. Very good points to consider.

While it is far out (aka 240 hours), the 12z Euro operational run does appear to dump an Arctic "motherlode" into the Plains. I wonder if we're already seeing the teleconnection between the SSW event and the model runs. Something to watch for sure.