January Weather Discussion: Slight Chance Severe Storms

[Andrew]

Canada is looking a little warmer this morning, hopefully it will get a fresh batch of bitter air before the front comes down.

[cisa]

That looks pretty cold.

[Andrew]

That looks pretty cold.

Yea I don't think we are missing any cold air. At least Alaska would say that.

[Ptarmigan]

12Z GFS says nothing for Houston. You'll have to go much farther SOUTH for snow.

http://www.twisterdata.com/data/models/ ... URFACE.png

It will flip-flop again.

[srainhoutx]

Goodness. Look at the cold air diving S via the 12Z Euro...storm nearing TX @ hour 216...

01232011 12Z Euro f144.gif

01232011 12Z Euro f168.gif

01232011 12Z Euro f216.gif

[srainhoutx]

HPC suggesting the Arctic Front will have a big push S next weekend...

EXTENDED FORECAST DISCUSSION
NWS HYDROMETEOROLOGICAL PREDICTION CENTER CAMP SPRINGS MD
140 PM EST SUN JAN 23 2011

VALID 12Z WED JAN 26 2011 - 12Z SUN JAN 30 2011

GUIDANCE OFFERS A COMPLICATED SHORT RANGE MESS INTO MIDWEEK WITH
MUCH ABOVE NORMAL FORECAST SPREAD WITH POTENTIAL SRN STREAM STORM
DEVELOPMENT AND ASSOCIATED HEAVY PCPN POTENTIAL OUT FROM THE SERN
US AND UP/OFF THE EAST COAST INTO THU. UNCERTAINTY WITH UPSTREAM
KICKER ENERGY...CONVECTIVE FOCUS...AND NRN STREAM INTERACTION HAS
LEAD TO SIGNIFICANT TIMING AND SUPPRESSION ISSUES WITH THE STORM.
THE OO UTC ECMWF/UKMET/CANADIAN AND TO A LESSER EXTENT THE 00 UTC
GFS CONTINUE TO FAVOR A DEEPENING LOW TRACK MORE ON THE WESTWARD
PORTION OF THE ENTIRE SOLUTION ENVELOPE IN STARK CONTRAST TO THE
MORE SUPPRESSED 00 UTC NOGAPS AND 06 UTC GUIDANCE INCLUDING THE
NAM/DGEX AND ESPECIALLY 06 UTC GFS THAT WAS LESS PROGRESSIVE WITH
BOTH SRN STREAM KICKER ENERGY AND LEAD LOW DEVELOPMENT. THIS
ALLOWS NRN STREAM FLOW TO BE MORE DOMINANT LEADING TO A FARTHER
OFFSHORE TRACK OF THE STORM. THE 12 UTC GFS HAS BACKED OFF FROM
THIS. ECMWF ENSEMBLES HAVE BEEN UNCHARACTERISTICALLY PROGRESSIVE
THAN GFS ENSEMBLES ALOFT WITH ENERGIES MOVING INTO AND OUT FROM
THE MEAN EAST-CENTRAL US TROUGH POSITION ALOFT CONSIDERING THE
AMPLITUDE OF MEAN RIDGING CENETERED OVER WRN NORTH AMERICA. 00
UTC ECMWF ENSEMBLES HAVE TRENDED SLIGHTLY SLOWER THAN YESTERDAYS
12 UTC RUNS...BUT REMAIN ON THE PROGRESSIVE SIDE OF THE ENTIRE
SOLUTION ENVELOPE. OVERALL...PREFER TO MAINTAIN HPC CONTINUITY
AMID UNCERTAINTY WITH A SOLUTION STILL PRIMARILY DERIVED FROM A
50-50 BLEND OF THE 00 UTC ECMWF AND REASONABLY SUPPORTIVE 00 UTC
GFS ENSEMBLE MEAN. ALTHOUGH...ANY OF THESE AVRIED SOLUTIONS
REMAIN PLAUIBLE IN THIS SENSITIVE FLOW PATTERN...AT LEAST THE
NEWER CLUSTER OF 12 UTC GFS ENSEMBLE MEAN/ECMWF/UKMET SEEM IN LINE
WITH THIS BLENDED HPC SOLUTION.

THIS HPC BLENDED SOLUTION ALSO SEEMS REASONABLE WITH UPSTREAM
DIFFERENCES THAT DEVELOP LATER NEXT WEEK FOR THE MOST PART. BY
FRI...A 50-50 00 UTC ECMWF/GFS ENSEMBLE MEAN BLEND FAVORS A
MODERATELY AMPLIFIED MID-UPPER LEVEL TROUGH OVER THE SRN/SERN US
WHOSE DYNAMICS MAY BE SUFFICIENT TO AID DEVELOPMENT OF SOME SERN
US/FL PCPN HEADING INTO THE WEEKEND DESPITE LIMITED SURFACE
RESPONSE.

FARTHER UPSTREAM...HIGHLY ENERGETIC FLOW ACROSS W-CENTRAL PACIFIC
UP TOWARD THE NERN PAC THIS WEEK IS RIPE WITH POTENTIAL EMBEDDED
SYSTEM ERROR LEADING TO GUIDANCE DIFFERENCES WITH ENERGY FLOW
CUTTING UNDERNEATH ACROSS THE NWRN US NEXT WEEKEND. THE 00 UTC
GFS AND ESPECIALLY 00 UTC ECMWF OFFER MORE SYSTEM ENERGY INTO THE
REGION...BUT PREFER TO BACK-OFF FROM THAT INCREASINGLY TOWARD
RECET FLATTER ENSEMBLE MEAN GUIDANCE CONSIDERING THE AMBIENT LEAD
MEAN RIDGE STRENGTH.

MEANWHILE...GUIDANCE IS ACTUALLY IN BETTER AGREEMENT WITH THE IDEA
OF DEVELOPING A DEEP NRN STREAM LOW TRACKING ACROSS SRN CAANDA
FROM JUST NORTH OF THE DAKOTAS FRI...GREAT LAKES SAT...AND NEW ENG
BY NEXT SUN. THE 00Z GFS APPEARS A LITTLE TOO MUCH ON THE QUICK
SIDE OF THE FULL SOLUTION ENVELOPE WITH THIS SYSTEM CONSIDERING
AMPLITUDE AND OUR 50-50 00 UTC ECMWF/GFS ENSEMBLE MEAN SOLUTION
THAT ALSO STILL HAS AMPLE SUPPORT FROM A COMPOSITE OF OTHER
GUIDANCE OFFERS REASONABLE PREDICTABILITY AND WOULD ALSO ALLOW FOR
QUITE A TRAILING COLD FRONTAL PUSH DOWN THROUGH THE CENTRAL AND
ERN US IN THE WAKE OF THE MAIN LOW.

ROTH/SCHICHTEL

[Mr. Weather]

why is accuweather and the weather channel not showing a chance for snow come the 1st of February for houston area

[Andrew]

why is accuweather and the weather channel not showing a chance for snow come the 1st of February for houston area

Well first off this event isn't really expected to hit until the 2nd or so. Secondly forecasts that far out are just pure model data. That forecast may be from another model that doesn't show snow. Being this far out we need to not pay attention to specifics and look at the upper dynamics more than the precip and certain degrees.

[randybpt]

Wxman, andrew srain......what temps could we be looking at with this front would love to fire up the snow gun...

[Andrew]

Wxman, andrew srain......what temps could we be looking at with this front would love to fire up the snow gun...

Here is what Wxman had to say yesterday: ( I also think the same thing)

If we step back and take a look at some of the signals that we're seeing, then it seems likely that there will be some type of significant event at the beginning of February. When I say that the pattern evolving appears similar to 1993, I don't mean that I expect another massive Gulf and east coast storm. It's possible that the pattern just leads to a major nor'easter.

What we do know is that there is some VERY cold air up in Canada now, and lots of it. With the pattern evolving, we have a very good shot at getting some quite cold Arctic air down here. Whether or not we get any frozen precip will depend on the details in the upcoming pattern - something we can't be sure of this far out.

The way I see it, there are 3 main possibilities for next week (around Feb 1-3):

1. Models are incorrect with the overall pattern and it's just more of the same (current weather). I'd say this isn't the highest probability, probably the lowest probability of the 3 options.

2. Significant dry surge of Canadian/Arctic air that may drop temps into the 20 degree range here or lower. Very hard freeze but no precip involved.

3. Moderately cold Canadian/Arctic air intrusion with secondary impulse moving through the cold air. This is what the GFS is forecasting and the Euro is hinting at around day 11-12.

I'm not ready to buy #3 just yet, but I could easily believe that we could get quite cold here in 9-10 days (#2 above). It's just so hard to get the timing and conditions here right for snow.

[BiggieSmalls]

I'm guessing low 20's in Houston means low teens in DFW?

[ticka1]

Can we rename this thread:

"AS THE SNOW TURNS" ?????? Drama drama drama with each run and dang if its always 10 days away!!!!

[Andrew]

I'm guessing low 20's in Houston means low teens in DFW?

Not exactly. Moisture levels could be different in each city and there are other factors that could influence the temps. Just too far out to really say at this point.

[srainhoutx]

Can we rename this thread:

"AS THE SNOW TURNS" ?????? Drama drama drama with each run and dang if its always 10 days away!!!!

We're saving that for Ed's February Thread.

[Baseballdude2915]

I'm guessing low 20's in Houston means low teens in DFW?

At this point, just know that it will be below average the first of February. ABOUT how much below average should be known by Thursday of this week. Maybe.

[Andrew]

Can we rename this thread:

"AS THE SNOW TURNS" ?????? Drama drama drama with each run and dang if its always 10 days away!!!!

Well this was 15 days out and now it is 10 days out. This is different then some of the other "phantom" storm systems the GFS paints for many reasons. First off there is model support all around with most all models indicating some type of cold blast with POSSIBLE moisture. Secondly this system didn't just "pop" up. It has been around since the extended GFS and has continued to appear in most runs. Does this mean it will actually happen? maybe, maybe not. Time will tell but this is defiantly not like those runs in the past.

[wxman57]

Folks, I wouldn't get too hung up on one model run or another this far out. The air in Canada is extremely cold, and it appears to be coming down next week. There are signs that disturbances will continue to track across the cold air once it gets here, and that's what could give the Deep South some snow. We won't know the details for another 7-8 days or so (maybe next Sunday). Until then, it doesn't matter a whole lot what the models do from run to run, as long as the same general upper air pattern is forecast. The 10-day euro does indicate some very cold air across our area AND with a big upper-level disturbance tracking into Texas on day 11. That's a recipe for snow, I just can't tell how far south yet.

[srainhoutx]

Another thing to add, we have a wet forecast for tomorrow concerning heavy rainfall and possible storms near the coast and offshore. Then we get the cold core upper low. We have a full plate ahead...

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HOUSTON/GALVESTON TX
235 PM CST SUN JAN 23 2011

.DISCUSSION...
SOME LIGHT ECHOES ON RADAR ARE BEGINNING TO SHOW UP IN THE HILL COUNTRY
AREA AND NORTH/NORTHEAST TEXAS IN ASSOCIATION WITH AN APPROACHING COLD
FRONT AND AROUND THE CRP AREA IN ASSOCIATION WITH A STRENGTHENING LOW
LEVEL JET AND DEEPENING MOISTURE LEVELS. AS THE WEAK FRONT SLOWLY MOVES
ACROSS THE AREA OVERNIGHT AND SURFACE LOW PRESSURE BEGINS TO DEVELOP
OFF THE LOWER TEXAS COAST...ANTICIPATE RAIN COVERAGE TO INCREASE ACROSS
MUCH OF SOUTHEAST TEXAS. GOOD RAIN CHANCES (RAIN/RAIN SHOWERS INLAND...
RAIN/RAIN SHOWERS AND ISOLATED THUNDERSTORMS OFFSHORE) WILL PERSIST
THROUGH MUCH OF THE DAY ON MONDAY AS THE SURFACE LOW PARALLELS THE
COAST ON ITS NORTHEAST TRACK. RAIN CHANCES WILL LOWER FROM WEST TO
EAST ON MONDAY NIGHT AND TUESDAY AS THE LOW MOVES OFF TO THE EAST
AND AN UPPER LEVEL TROUGH WORKS ITS WAY EASTWARD ACROSS TEXAS. RIGHT
NOW...IT LOOKS LIKE THE AREA WILL DRY OUT BEFORE TEMPERATURES COOL
DOWN ENOUGH AND SOUNDING PROFILES BECOME SUPPORTIVE FOR ANY FROZEN
PRECIPITATION. THE REST OF THE WEEK LOOKS DRY AND COOL WITH A SERIES
OF REINFORCING COLD FRONTS MOVING THROUGH THE AREA. WE COULD SEE
SLIGHTLY WARMER TEMPERATURES AS WE HEAD ON INTO NEXT WEEKEND BEFORE
THE PASSAGE OF THE NEXT COLD FRONT. THE TIMING AND STRENGTH OF THIS
FRONT REMAINS VERY UNCERTAIN DUE TO DIFFERING MODEL SOLUTIONS. 42

[srainhoutx]

Some interesting discussions this afternoon across TX concerning next weekend and beyond...

Dallas/Ft Worth:

DIFFERENCES ON SYSTEMS REALLY GET REALIZED DAY 7/BEYOND AS THE GFS
ADVERTISES A STRONG SYSTEM ARRIVING SUN/MON IN THE SRN STREAM/
CONVERGENT UPPER FLOW OVER TX...WHILE THE ECMWF IS WEAKER/SLOWER/
AND FURTHER SOUTH WITH THIS FEATURE WITH BULK OF ANY PRECIPITATION
POTENTIAL REMAINING WELL TO THE SOUTH OF OUR AREA. AS STATED...WE`RE
ON BOARD WITH THE ECMWF FOR THE TIME BEING AND WITH IT`S BETTER
TRACK RECORD BEYOND DAY 5 IN MOST CASES.

Midland/Odessa:

THE GENERAL PATTERN THAT WE/VE BEEN IN CAN BE CHARACTERIZED AS A
COLD PROGRESSIVE. FROM A PACIFIC NORTH AMERICAN PATTERN OR
TELE-CONNECTIONS PERSPECTIVE THE W COAST RIDGE HAS FAVORED A
MERIDIONAL MID LEVEL COMPONENT AND THUS FREQUENT COLD FRONTS.
FREQUENCY OF COLD FRONTS/SOURCE REGIONS IN PART ARE LIMITING THE
CHANCE OF SIG PRECIP THIS FAR W AS THERE HAVE BEEN ONLY SMALL
WINDOWS FOR MSTR TO RETURN AHEAD OF FRONTS...NOT SO MUCH FARTHER SE
INTO THE STATE. FURTHER THE POSITIVE PNA PATTERN OF LATE IS IN
ALIGNMENT WITH A NEGATIVE PHASE OF THE ARCTIC OSCILLATION...THUS
AIDING THE COLD PART OF THE PROGRESSIVE PATTERN. USING 6-10 DAY
AND 8-14 DAY 5H ANOMALY CHARTS THE POSITIVE PNA PATTERN (RIDGE IN
THE W) SHOWS VERY LITTLE CHANGE IN THE AMPLITUDE OF THE PATTERN.
MEANWHILE THE ENSEMBLE RUNS OF THE ARCTIC OSCILLATION DO SHOW A
TREND UPWARD WHILE THE DETERMINISTIC MODELS GFS/ECMWF HINT THAT
MID LEVEL RIDGE WILL BE A LITTLE FARTHER W. ALL TO SAY THAT THERE
IS NOT A STRONG SIGNAL THAT THE PATTERN WILL CHANGE WITHIN THE
NEXT 2 WEEKS.

Corpus Christi:

BEYOND FRIDAY THE NEXT QUESTION IS HOW THE UPPER LOW OVER THE BAHA
REGION WILL LIFT OUT AND WHEN. THE ECMWF LOOSES THE SYSTEM ALL
TOGETHER WHILE THE GFS/CANADIAN MODELS BEGIN TO EJECT THE SYSTEM AND
BRING IT ACROSS NE MEXICO TOWARD SOUTH TX FRI NGT/SAT. MOISTURE AND
FORCING LOOKS BETTER WITH THIS FEATURE THUS ADDED 20/30% POPS.
MEANWHILE...THE UPR PATTERN BEGINS TO BUCKLE WITH A STRONG MID/UPR
LVL RIDGE BUILDING BACK OVER WESTERN CANADA AND A DEEP COLD TROUGH
BECOMING AMPLIFIED OVER HUDSON BAY. SFC TEMPERATURE READINGS THE PAST
COUPLE DAYS ACROSS MUCH OF CENTRAL CANADA HAVE BEEN FRIGID...HOVER
IN THE -20 TO -50 DEG F RANGE. IF THIS TROUGH AMPLIFIES...WE COULD
SEE THE COLDEST AIRMASS OF THE SEASON BEGIN TO SURGE INTO THE NATION
EAST OF THE ROCKIES...WITH THE INITIAL EDGE OF THE FRONT REACHING
SOUTH TEXAS MONDAY AFTN. THE AIRMASS WOULD MODIFY SIGNIFICANTLY
BEFORE REACHING SOUTH TEXAS BUT RAW GFS SFC TEMPS INDICATE HIGHS IN
THE MID 20S-MID 30S ACROSS THE CWA ON TUE. (HAVEN`T SEEN TEMPS THIS
COLD IN CANADA ALL SEASON UNTIL NOW) AGAIN THERE IS CONSIDERABLE
UNCERTAINTY SO WE`LL HAVE TO WATCH THIS CLOSELY AS TIME DRAWS
CLOSER. COULD BE SOME POST FRONTAL PCPN MONDAY AS BOTH THE
GFS/ECMWF PROG A FAIRLY DEEP LAYER OF MOISTURE OVER SOUTH TEXAS AND
AND UPR LVL S/W ENERGY TO PROPAGATE OVER THE REGION.

[Andrew]

Nam was not as cold as the 12z but just as wet. 18z GFS running now

http://www.nco.ncep.noaa.gov/pmb/nwprod ... el_l.shtml