January Weather Discussion: Slight Chance Severe Storms

[srainhoutx]

Speaking of models, the 00Z NAM looks mighty wet...

01152011 00Z nam_ref_024l.gif

01152011 00Z nam_ref_036l.gif

01152011 00Z nam_ref_042l.gif

[tireman4]

The current GFS?

Nothing but a tropical storm moving into S TX/NE MX...

Oh man, what a winter. Tropical storms, Lucy ticking off Portastorm and Dan being channeled for his snow gun. Gosh, I love meteorology!!!

[Katdaddy]

LOL! Weather is life. You never what life will throw at you.....its all about how ride the storm. Models can be the best comedy.

And I really miss Dan

[redneckweather]

You drinkin tonight Katdaddy?

[Andrew]

GFS suggests some arctic dumps over the U.S. over the next couple of weeks

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

[wxman57]

The Canadian and Euro are in fairly good agreement (00Z run) in the cold air reaching Texas late Wed or on Thursday morning, but with the trof axis still to the west. What I see is not a deep layer of cold air but a shallow sub-freezing airmass to our north and northwest (hill country through Dallas to OK/KS and east. This is a setup for a freezing rain event to our north on Thursday into Friday morning, not a snow event. It's something we expected might be more likely during a La Nina winter.

GFS has the trof axis to our east with a dry frontal passage on Thursday. I'd tend to believe the Canadian/Euro solution for now. Nothing for us but probably 30s-40s with rain. But that all depends on just how far south that shallow sub-freezing layer gets. I don't see how we could get snow out of this, just freezing rain or sleet. The cold air would have to be thicker.

Oh, and THIS is the type of front (shallow cold Arctic air with trof to the west) that the models will likely miss by quite a ways. They may show it in OK while it's really already out in the Gulf.

[redneckweather]

From wxman (doing my own quote format since the one in this forum just ain't cuttin it): What I see is not a deep layer of cold air but a shallow sub-freezing airmass to our north and northwest (hill country through Dallas to OK/KS and east. This is a setup for a freezing rain event to our north on Thursday into Friday morning, not a snow event.


With arctic air coming down, shallow or not, you wouldn't think it would get hung up just to our north do ya?

[srainhoutx]

Nothing severe is expected, but some elevated storms cannot be ruled out overnight into Sunday morning across the area...

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE HOUSTON/GALVESTON TX
412 AM CST SAT JAN 15 2011

GMZ330-335-350-355-370-375-TXZ163-164-176>179-195>200-210>214-226-
227-235>238-161300-
AUSTIN-BRAZORIA-BRAZOS-BURLESON-CHAMBERS-COLORADO-FORT BEND-
GALVESTON-GALVESTON BAY-GRIMES-HARRIS-HOUSTON-JACKSON-LIBERTY-
MADISON-MATAGORDA-MATAGORDA BAY-MONTGOMERY-POLK-SAN JACINTO-
TRINITY-WALKER-WALLER-WASHINGTON-
WATERS FROM FREEPORT TO THE MATAGORDA SHIP CHANNEL 20 NM TO 60 NM-
WATERS FROM FREEPORT TO THE MATAGORDA SHIP CHANNEL OUT 20 NM-
WATERS FROM HIGH ISLAND TO FREEPORT 20 TO 60 NM-
WATERS FROM HIGH ISLAND TO FREEPORT OUT 20 NM-WHARTON-
412 AM CST SAT JAN 15 2011

THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF SOUTHEAST TEXAS.

.DAY ONE...TODAY AND TONIGHT

RAIN CHANCES WILL BE ON THE INCREASE AS THE DAY PROGRESSES WITH THE
BEST CHANCE COMING TONIGHT AS A STORM SYSTEM MOVES ACROSS SOUTH TEXAS.

.DAYS TWO THROUGH SEVEN...SUNDAY THROUGH FRIDAY

IT WILL RAIN ON SUNDAY AS A STORM SYSTEM MOVES ACROSS THE AREA. SOME
TRAINING RAINS ARE POSSIBLE WHICH COULD LEAD TO SOME LOCALLY HEAVY RAINFALL.
RAINFALL TOTALS ARE EXPECTED TO AVERAGE BETWEEN 1 AND 2 INCHES WITH
ISOLATED 2 TO 3 INCH AMOUNTS POSSIBLE WHERE TRAINING DEVELOPS.



DAY 2 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1202 AM CST SAT JAN 15 2011

VALID 161200Z - 171200Z

...NO SVR TSTM AREAS FORECAST...

...SYNOPSIS...

BROAD LOW AMPLITUDE SYNOPTIC TROUGH WILL PERSIST OVER THE ERN U.S.
WITH AN UPSTREAM RIDGE FROM THE PACIFIC NW SWD INTO CA. THE INITIAL
SHORTWAVE TROUGH THAT WILL BE NEAR S TX EARLY SUNDAY WILL DEAMPLIFY
AND WEAKEN AS IT EJECTS INTO THE WRN GULF IN RESPONSE TO ANOTHER IN
A SERIES OF IMPULSES THAT WILL DROP SEWD INTO TX DURING THE DAY. A
WEAK SURFACE WAVE AND COLD FRONT WILL LIKELY ACCOMPANY THE STRONGER
IMPULSE THROUGH SERN TX.

...SRN THROUGH ERN TX INTO THE LOWER MS VALLEY...

ZONE OF DEEPER ASCENT AND HEIGHT FALLS ACCOMPANYING THE SHORTWAVE
TROUGH SHOULD CONTRIBUTE TO MAINTENANCE OF SLY LLJ OVER ERN TX AND
EVENTUALLY SHIFTING INTO THE LOWER MS VALLEY. THREAT FOR A FEW
THUNDERSTORMS WILL LINGER WITHIN ZONE OF WARM ADVECTION AND
ISENTROPIC ASCENT AHEAD OF FRONT ACROSS ERN TX AND THE LOWER MS
VALLEY. ELY TRAJECTORIES EMANATING FROM CP HIGH PRESSURE WILL TEND
TO MAINTAIN A STABLE BOUNDARY LAYER AND LIMIT NWD PROGRESSION OF
WARM FRONT AND HIGHER DEWPOINTS EXCEPT ALONG SRN TX COASTAL AREAS.
FOR THIS REASON MOST CONVECTION SHOULD REMAIN SLIGHTLY ELEVATED.
WEAK LAPSE RATES WILL FURTHER MITIGATE DESTABILIZATION POTENTIAL.
GIVEN THE EXPECTED LIMITED MOISTURE RETURN AND WEAK THERMODYNAMIC
ENVIRONMENT...ANY SEVERE THREAT APPEARS LOW AT THIS TIME.

..DIAL.. 01/15/2011

[wxman57]

From wxman (doing my own quote format since the one in this forum just ain't cuttin it): What I see is not a deep layer of cold air but a shallow sub-freezing airmass to our north and northwest (hill country through Dallas to OK/KS and east. This is a setup for a freezing rain event to our north on Thursday into Friday morning, not a snow event.


With arctic air coming down, shallow or not, you wouldn't think it would get hung up just to our north do ya?

No, it won't get hung up. I still have all the model forecasts (printed maps I saved - there was no internet) from the 1993 November Arctic front. It's the one that was totally blown by NWS offices from Houston to OKC. The freezing rain event impacted the Dallas Cowboy's game, the one with the famous Leon Lett flub. At the office, we call it the "Leon Lett Bowl" game. NWS offices didn't see the cold air and they questioned the availability of moisture. "I just can't see the moisture" is a quote we often recite at the office, remembering that event.

In the 1993 event, the Arctic air began moving south to the lee of the Rockies. The models predicted a DEEP upper low to the west over Utah (closed low there). Strong southerly winds at 500mb from Texas northward. Models initially moved the front south then drove it back to the north due to the southerly winds aloft. Problem is, Arctic air doesn't care what the winds are aloft. Just 2 days before the Arctic air was to reach Houston, the models had the front way up in northern OK/KS and moving north as a warm front. In reality, the front was well out into the Gulf when the models had it in Kansas moving north. We eventually had an extended period of upper 30s and rain in Houston, with sleet and freezing rain across much of Texas and Oklahoma.

This is a similar setup I see developing. Of course, the boundary between miserable cold rain and freezing rain is impossible to pick out this far in advance. We'll have to see just what kind of cold air moves southward. The air in western Canada is quite cold, possibly colder than in the Nov. 1993 event.

Have I mentioned I hate cold weather lately (last 15 minutes)?

[sleetstorm]

We are, needless to say, gradually coming upon the middle of Winter.

[Portastorm]

Ed, I checked the storm database for a Feb. 94 ice storm in Austin and nothing shows. I was here (Austin) then as well and don't remember anything, although sometimes I can't remember what I ate for lunch yesterday so that doesn't matter too much!

There was a major ice storm in Feb 94 in northeast-east Texas where temps dropped some 60 degrees and some areas saw as much as up to 4 inches of ice/sleet.

But you are correct about the ramps on and off I-35 in downtown. They still ice over easily and the upper deck of I-35 is usually the first thing to close down when ice happens in Austin.

[srainhoutx]

12Z GFS suggests some moisture for Portastorm and our neighbors in West Central/Central TX on Friday...

[srainhoutx]

The 12Z Canadian (GEM) looks messy across TX Thursday/Friday as the Arctic boundary pushes S...

[srainhoutx]

New Update from SPC...

DAY 2 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1046 AM CST SAT JAN 15 2011

VALID 161200Z - 171200Z

...NO SVR TSTM AREAS FORECAST...

...SYNOPSIS...
AS PART OF A BROADER LONGWAVE TROUGH...MULTIPLE PORTIONS OF A LOW
LATITUDE SHORTWAVE TROUGH OVER TX/NORTHERN MEXICO ARE EXPECTED TO
PHASE/PROGRESS EASTWARD TOWARD THE LOWER MS VALLEY/CENTRAL GULF
COAST ON SUNDAY. THE PREVALENCE OF HIGH PRESSURE AND A COOL/STABLE
AIRMASS EAST OF THE ROCKIES WILL ENSURE AN UNEVENTFUL DEEP
CONVECTIVE DAY IN MOST LOCALES...ALTHOUGH TSTMS WILL BE POSSIBLE
ACROSS PORTIONS OF SOUTHEAST TX/NEAR-COASTAL LA.

...SOUTHEAST TX TO COASTAL LA...
THE PRIMARY MARINE BOUNDARY/ASSOCIATED MARITIME AIRMASS IS EXPECTED
TO REMAIN OFFSHORE ON SUNDAY...AS THE INLAND CP AIRMASS REMAINS
LARGELY UNMODULATED OWING TO MIDWEST HIGH PRESSURE ASSOCIATED
TRAJECTORIES AND EARLY DAY PRECIPITATION INLAND. HOWEVER...WARM
ADVECTION/DEEPER FORCING ASSOCIATED WITH THE PASSING SHORTWAVE
TROUGH AND AN ELEVATED WEAK CAPE ENVIRONMENT WILL SUPPORT SOME
ISOLATED/EMBEDDED TSTMS. THIS WILL BE THE CASE EARLY IN THE PERIOD
FOR COASTAL/INLAND AREAS OF SOUTHEAST TX...WITH THE MAJORITY OF
TSTMS OTHERWISE CONCENTRATED OFFSHORE THE TX/LA COASTS. SEVERE TSTMS
ARE NOT EXPECTED.

..GUYER.. 01/15/2011

[Portastorm]

The 12z UKMET also shows a much colder pattern for late next week based on the progged 500mb flow.

http://www.meteo.psu.edu/~gadomski/UKHE ... kloop.html

[TexasBreeze]

Another arctic front watch in effect for next week! The only things to watch are timing and trajectory of the cold air. The cold air is already up there and really cold this time compared to the last week front.

[Mr. Weather]

So with this new blast coming through what is Houston looking at getting maybe somemore rain and a few days of lows possibly in the 30 's ?? What about the highs ? And any chance for a wintery mix this time ? J/w thanks

[srainhoutx]

Another arctic front watch in effect for next week! The only things to watch are timing and trajectory of the cold air. The cold air is already up there and really cold this time compared to the last week front.

A snip from Fairbanks this morning certainly verifies that...

VERY COLD TEMPS OF 40-50 BELOW NOW IN THE YUKON FLATS AND UPPER
YUKON VALLEY WILL MODERATE A BIT WITH CLOUDS TODAY AND TONIGHT.
DRAINAGE OF THIS COLD AIR DOWN THE TANANA VALLEY IS CAUSING WIND
CHILL ADVISORIES NOW THROUGH EARLY SUN.

[srainhoutx]

The 12Z Euro paints a nasty pattern across the Panhandle/N Cenrtal/N and NE TX as the Arctic boundary pushes S on Thursday. That model suggests an Upper Air disturbance dropping SE along the Rockies behind the frontal boundary.

01152011 12Z Euro f120.gif

01152011 12Z Euro f144.gif

01152011 12Z Euro f168.gif

[sambucol]

Any frozen precip showing for our area? We're having UIL competition Friday night with kids traveling to the event on buses. Just wondering if there's going to be a chance of ice. Thanks.