TX Winter Wx Threat # 9--- Another Arctic Outbreak?

[Kludge]

OK, we got the arctic cold on the way now lets turn our heads and look to the gulf or baja CA for the upper low so we can make some good use of this cold air.

I like how you think, Cap'n...! Let's get all the ingredients into the recipe. Bitter cold would be just miserable (and a pain in the a__) unless we can add some precip to it. And this time, maybe thicknesses would allow for sn__ (being careful not to jinx!).

[aggiecutter]

Portastorm, go and check the EURO again. You will see cross polar flow down into Texas Friday through Sunday. However cold the air is to the north, it is going to drive it down into Texas.

0z EURO: Change the dates with the drop down menu:
http://www.ecmwf.int/products/forecasts ... uv850_z500

[aggiecutter]

Hello winter storm. This was on the 0z run also:

GFS 192:
http://www.nco.ncep.noaa.gov/pmb/nwprod ... _192.shtml

[HouTXmetro]

I don't know how to read those maps, but does it seams the latest models indicates the coldest air is targeting Texas again as vs a "glancing blow"?

[Extremeweatherguy]

Hello winter storm. This was on the 0z run also:

GFS 192:
http://www.nco.ncep.noaa.gov/pmb/nwprod ... _192.shtml

actually that is the new 12z run of the GFS, but yes it is interesting to see it finally starting to come around.

http://www.nco.ncep.noaa.gov/pmb/nwprod ... _204.shtml
^^Look at all this cold air is shows in the state by the evening of Monday the 5th^^


http://www.nco.ncep.noaa.gov/pmb/nwprod ... _216.shtml
^^And by the morning of Tuesday the 6th, we are all in a deep freeze.^^

Now we just have to see if the GFS can finally lock onto this trend in later runs...

[Extremeweatherguy]

BTW, here is a look at the 12z GFS surface numbers forecasted for IAH...

Monday, Feb. 5th
6pm - 35

Tuesday, Feb. 6th
6am - 27
6pm - 33

Wednesday, Feb. 7th
6am - 21 <<If IAH is at 21, then the northern suburbs could easily be in the teens
6pm - 30

Thursday, Feb. 8th
6am - 24
6pm - 37

The GFS does still seem a bit slow in getting the main blast of cold air here though. The 12z wants to hold the REAL chilly air off until Monday night, but I think it could arrive a bit sooner.

[srainhoutx]

BTW, here is a look at the 12z GFS surface numbers forecasted for IAH...

Monday, Feb. 5th
6pm - 35

Tuesday, Feb. 6th
6am - 27
6pm - 33

Wednesday, Feb. 7th
6am - 21 <<If IAH is at 21, then the northern suburbs could easily be in the teens
6pm - 30




Thursday, Feb. 8th
6am - 24
6pm - 37

The GFS does still seem a bit slow in getting the main blast of cold air here though. The 12z wants to hold the REAL chilly air off until Monday night, but I think it could arrive a bit sooner.

Wasn't GFS about 24 to 48 hours slow last event?

[Extremeweatherguy]

BTW, here is a look at the 12z GFS surface numbers forecasted for IAH...

Monday, Feb. 5th
6pm - 35

Tuesday, Feb. 6th
6am - 27
6pm - 33

Wednesday, Feb. 7th
6am - 21 <<If IAH is at 21, then the northern suburbs could easily be in the teens
6pm - 30

Thursday, Feb. 8th
6am - 24
6pm - 37

The GFS does still seem a bit slow in getting the main blast of cold air here though. The 12z wants to hold the REAL chilly air off until Monday night, but I think it could arrive a bit sooner.

Wasn't GFS about 24 to 48 hours slow last event?

yes and no. The front did reach Houston a good 24 hours ahead of when it should have, but then it also did stall and meander during the next 24 hours around the city.

Basically, in the end, for areas like Brenham and NW of Houston it was a good 24-36 hours too slow, while in places like Galveston it was only about 0-6 hours too slow.

[gboudx]

Might want to pay more attention to what Norman is putting in the AFD's this week.

LONG TERM...
DETAILS ARE BEGINNING TO EMERGE FOR LATE WEEK - AND THEY ARE NOT
PRETTY. LONGWAVE EVOLUTION CONTINUES TO POINT STRONGLY TOWARD A
MASSIVE INVASION OF FRIGID AIR OVER VIRTUALLY ALL OF CENTRAL/E
CANADA AND MUCH OF THE CENTRAL/E CONUS... WITH THE BRUNT OF IT
LIKELY TO BECOME ONE FOR THE AGES FOR PARTS OF E CANADA AND
ADJACENT N-CENTRAL/NE STATES. STRENGTH AND AMPLITUDE OF THE
IMPRESSIVE RIDGE PROGGED ALONG THE W COAST OF N AMERICA - AND THE
EQUALLY IMPRESSIVE DOWNSTREAM VORTEX OVER HUDSON BAY - SUGGEST
THAT THE ARTIC AIR EVENTUALLY WILL BE FELT TO SOME DEGREE EVERYWHERE
E OF THE ROCKIES. GIVEN THE MASSIVE POOL OF DEEP COLD AIR THAT ALL
OF THE MODELS LOAD UP FROM HUDSON BAY INTO THE N PLAINS
/THICKNESSES BELOW 500 OVER A HUGE AREA WITH CORE MINIMA IN THE
470S/ THIS IS LIKELY TO BE ANOTHER STRUGGLE FOR THE MODELS. AS IS
OFTEN THE CASE... THE ARCTIC AIR MOST LIKELY WILL BE FASTER
STRONGER AND COLDER THAN PROJECTED BY ANY OF THE MODELS. ON THIS
BASIS WE ARE ANTICIPATING THE MORE SIGNIFICANT COLD AIR TO ARRIVE
HERE AS EARLY AS THU... OR AS MUCH AS A DAY BEFORE CURRENTLY
INDICATED BY MODEL GUIDANCE. WE ALSO HAVE LOWERED TEMPS THU AND
BEYOND TO WELL BELOW AVAILABLE MOS GUIDANCE... WITH READINGS
EXPECTED THAT MAY RIVAL OR EXCEED THE OUTBREAK OF MID JANUARY WHEN
MANY AREAS STAYED BELOW FREEZING FOR UP TO A WEEK. IF THERE WERE A
BIG MASS OF ARCTIC AIR UP THERE RIGHT NOW... READY AND WAITING TO
BREAK LOOSE... WE WOULD LOWER THE TEMPS EVEN MORE. STILL MAY NEED
TO DO THAT IN LATER FORECASTS.

PRECIP CHANCES ARE LIKELY TO CENTER AROUND THE UPPER LOW NOW NEAR
THE CENTRAL CA COAST. MODELS SEEM TO BE TRENDING TOWARD A
CONSENSUS OF SORTS... KEEPING THE LOW AS THE S PART OF AN E-PAC
BLOCK UNTIL MOVING IT OUT TOWARD S CA BY TUE. STILL A LOT OF
DETAILS TO BE WORKED OUT... BUT THE EVOLVING MODEL TRENDS WOULD
BRING THIS SYSTEM INTO THE S PLAINS ON OR ABOUT THURSDAY. AS SUCH
WE HAVE RAISED POPS TO CHANCE CATEGORY THU AND THU NIGHT. FOR
SIMPLICITY THE WX GRIDS WILL KEEP THE PRECIP TYPE AS RAIN AND/OR
SNOW... BUT THERE IS POTENTIAL FOR THIS TO TURN INTO ANOTHER
SIGNIFICANT ICE EVENT. ALL WILL DEPEND ON THE TIMING AND DEPTH OF
THE ARCTIC AIR. WE PREFER TO WAIT A BIT LONGER BEFORE HITTING THIS
EVENT MUCH HARDER... SINCE THERE ARE STILL SO MANY WAYS IT COULD
TURN OUT. SUFFICE TO SAY THAT THE UNFOLDING SCENARIO WILL NEED TO
BE MONITORED VERY CLOSELY IN THE COMING DAYS.

[Extremeweatherguy]

Off topic from the cold blast next weekend...

I have a feeling it will be getting colder than just 32 here in north Houston tonight. I am still only in the upper 40s at nearly 1pm (with sunny skies) and CAA continues to blow in lower and lower dewpoints. At noon Hooks airport had a dewpoint of 22 (down from 24 at 11am).

If this trend continues, then I wouldn't be surprised if areas of north Houston dipped into the 20s tonight (especially if the winds calm down and the skies stay clear). Could be one of the coldest nights so far this winter if things play out right. (Coldest so far was 30 at IAH, 28 at Hooks and 27 on my thermometer).

Update (2:20pm): The dewpoint has actually risen back up to 25 in the last few hours and the temperature is now in the lower 50s. Might wind up only being around 29-33 tonight after all.

[HouTXmetro]

Extreme what are the GFS guidance saying for Hobby?

[wxman57]

Extreme what are the GFS guidance saying for Hobby?

GFS guidance won't be of much use so far out. Maybe about 24 hours after the cold air arrives it'll catch on. For now, GFS is saying mid 40s to mid 60s next Sat-Sun-Mon.

[southerngale]

Any new thoughts today, wxman57?

[wall_cloud]

we're still undercutting the MEX (at least the 00Z run last night and the previous night) but good 20+ degrees. It actually has us warmer than climo over the weekend.

[double D]

A snippet from Austin/San Antonio afternoon discussion:

A GRADUAL WARMING TREND WILL ESTABLISH LATE IN THE WEEK AS DRY
WESTERLY WINDS MIX DOWN, ALLOWING AFTERNOON HIGHS TO REACH WITHIN
A FEW DEGREES OF EARLY FEBRUARY NORMALS. TRICKY FORECAST SITUATION
FOR THE WEEKEND, AS MAX TEMPS AFTER THURSDAY WILL BE HIGHLY
DEPENDENT UPON THE TIMING OF THE NEXT FRONT. GFS CONTINUES TO
INDICATE THE FROPA WON`T BE UNTIL SOME TIME ON SUNDAY, MEANING
SATURDAY`S MAX TEMPS WILL BE SIMILAR TO FRIDAY`S. THERE IS ALSO
THE FACTOR OF JUST HOW COLD THE FRONT WILL BE. ALTHOUGH ARCTIC IN
ORIGIN, THE AIRMASS WILL MODIFY BEFORE IT REACHES SOUTH CENTRAL
TEXAS. IN SHORT, FORECAST CONFIDENCE BEYOND THURSDAY IS NOT VERY
HIGH.

At least according to the NWS, it doesn't seem the front will be that bone chilling. Although they don't offer much explanation of the upcoming event.

[southerngale]

Well, at least they acknowledge that the front exists. NWS Lake Charles still hasn't mentioned it all. This afternoon's discussion doesn't get past Monday's and Tuesday's rains and the only mention of next weekend came from the overnight discussion. I guess they don't think the front will get here at all, not even a glancing blow? You'd think they'd say something.

From the 4:03am discussion...

POTENTIALLY STRONG SYSTEM COULD AFFECT THE AREA BY THURSDAY AND
FRIDAY AS AN UPPER LOW IS FORECAST TO DEEPEN OVER THE SW
CONUS...INCREASING SWLY FLOW ALOFT. GFS INDICATING DECENT MOISTURE
AND WARM AIR ADVECTION ACROSS SW LA AND SE TX. DYNAMICS APPEAR
FAVORABLE WHICH COULD PROVIDE A DECENT CHANCE OF THUNDERSTORMS
DURING THIS TIME PERIOD.

DRY WEATHER TO RETURN TO THE AREA BY THE WEEKEND AS HIGH PRESSURE
BUILDS AT THE SFC AND THE UPPER TROUGH MOVES EAST.


I'm beginning to think that this is much ado about nothing...again.

[double D]

Could north Texas see some snow?

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE FORT WORTH TX
307 PM CST SUN JAN 28 2007

TXZ091>095-100>107-115>123-129>135-141>148-156>162-174-175-291100-
ANDERSON-BELL-BOSQUE-COLLIN-COMANCHE-COOKE-CORYELL-DALLAS-DELTA-
DENTON-EASTLAND-ELLIS-ERATH-FALLS-FANNIN-FREESTONE-GRAYSON-HAMILTON-
HENDERSON-HILL-HOOD-HOPKINS-HUNT-JACK-JOHNSON-KAUFMAN-LAMAR-LAMPASAS-
LEON-LIMESTONE-MCLENNAN-MILAM-MILLS-MONTAGUE-NAVARRO-PALO PINTO-
PARKER-RAINS-ROBERTSON-ROCKWALL-SOMERVELL-STEPHENS-TARRANT-VAN ZANDT-
WISE-YOUNG-
307 PM CST SUN JAN 28 2007

...A WINTRY MIX IS POSSIBLE OVER PORTIONS OF NORTH TEXAS WEDNESDAY
THROUGH FRIDAY...

SEVERAL DISTURBANCES WILL APPROACH...AND MOVE ACROSS NORTH TEXAS
DURING THE WEDNESDAY TO FRIDAY TIME FRAME AND MAY GIVE NORTH TEXAS
SOME WINTER PRECIPITATION DURING THAT TIME. A COLD FRONT WILL MOVE
THROUGH NORTH TEXAS ON TUESDAY BRINGING MORE ARCTIC AIR INTO THE
REGION. TEMPERATURE PROFILES AT THIS TIME ARE FORECAST TO BE COLD
ENOUGH TO SUPPORT SOME LOW CHANCES FOR SLEET AND SNOW TO MIX WITH THE
RAIN.

BEGINNING WEDNESDAY AFTERNOON A MIX OF RAIN...SLEET...AND SNOW
IS POSSIBLE ALONG AND NORTH OF INTERSTATE 20. BY WEDNESDAY NIGHT...A
WINTRY MIX IS POSSIBLE ALONG AND NORTH OF A LINE FROM COMANCHE...
TO HILLSBORO...TO CANTON. THE WINTER PRECIPITATION IS EXPECTED TO
REMAIN NORTH OF THIS LINE THROUGH FRIDAY MORNING. HOWEVER...ON
THURSDAY NIGHT...COUNTIES CLOSE TO THE RED RIVER MAY SEE THE
PRECIPITATION CHANGE TO ALL SNOW. THE CHANCE FOR PRECIPITATION WILL
END ON FRIDAY MORNING FROM WEST TO EAST AS THE LAST UPPER LEVEL
DISTURBANCE MOVES OFF TO THE EAST. IF ANY ICE OR SNOW DOES
ACCUMULATE...TRAVEL WILL BE IMPACTED...ESPECIALLY ON BRIDGES AND
OVERPASSES WHICH TEND TO BE THE FIRST TO ICE OVER.

THE NATIONAL WEATHER SERVICE WILL CONTINUE TO MONITOR THIS EVENT AND
MAKE NECESSARY ADJUSTMENTS...AS THE SYSTEM EVOLVES. STAY TUNED TO
FUTURE FORECASTS FOR ANY CHANGES OR ADDITIONS REGARDING THIS EVENT.

REMEMBER...YOU CAN ALSO KEEP UP WITH THE LATEST FORECASTS AND MUCH
MORE ON OUR WEBSITE AT http://WWW.WEATHER.GOV/FORTWORTH

$$

82

[Portastorm]

Kudos to Amarillo's NWS office for this great AFD. Nice to see our hard-working government employees using their wits as well as their PCs. I was impressed by this as it takes a lot of "nerve" to deviate so much beyond the guidance numbers.

"GFS ENSEMBLES THROUGH 120 HR ARE IN REMARKABLY GOOD AGREEMENT ON THE
UPPER AIR PATTERN...THOUGH THE LOW LEVEL GFS FORECASTS LEAVE MUCH TO
BE DESIRED. PRIMARY ARCTIC DUMP /TM ERAJR/ STILL EXPECTED IN OVERNIGHT
THURSDAY...AHEAD OF THE GFS TIMING...WHICH HAS HELD UP THE COLD AIR.
HAVE FOLLOWED THE IDEA OF THE EURO FOR FRIDAY...AND MAINTAINED THE
COLD OVERCAST AIRMASS THROUGH SATURDAY AS WELL. FORECAST SOUNDINGS
SUGGEST THE AIRMASS WILL BE DEEP...AND GIVEN ITS STRENGTH AND
DEPTH...CAN NOT FOLLOW THE MODELS IN ERODING THE COLD AIR WITHIN 24
HOURS OF ITS ARRIVAL. THEREFORE...TEMPS BEGINNING FRIDAY ARE AS MUCH
AS 20 DEGREES BELOW GUIDANCE. POPS ARE BELOW MENTIONABLE VALUES AFTER
THURSDAY NIGHT...OWING TO INCREASING EXTENDED RANGE UNCERTAINTY."

[double D]

I think the Amarillo NWS need to teach some of the other NWS offices around the state a thing or two about how arctic fronts work.

[Extremeweatherguy]

"HMMM" is all I can say this afternoon after reading the latest Houston AFD and seeing the forecast.

The AFD is once again writing off any arctic air this weekend and just calling for "dry, cool" weather with a slight wind shift. Also, check out the latest forecast for north Houston this weekend...

Friday Night: Mostly clear, with a low around 39.

Saturday: Mostly sunny, with a high near 61.

Saturday Night: Partly cloudy, with a low around 42.

Sunday: Partly cloudy, with a high near 64.

I simply cannot believe what I am seeing! They are forecasting "seasonable" weather with partly cloudy skies. They show no hint at all of any cold weather, rain chances, nothing. They don't even make it seem like an arctic front would be possible next Mon - Tues either. It is kind of strange, especially since most other sources (including nearby NWS offices) are indeed talking about the possibility.


ALSO...

Then, in an even crazier move, the NWS also decided to drop our temperatures for this upcoming week by A LOT! Check out the latest forecast for this Tues - Thurs:

Tuesday: Rain likely, mainly before noon. Cloudy, with a high near 49. North wind between 5 and 15 mph. Chance of precipitation is 60%.

Tuesday Night: A 20 percent chance of rain before midnight. Mostly cloudy, with a low around 40. North wind between 10 and 15 mph.

Wednesday: A 30 percent chance of rain, mainly after noon. Mostly cloudy, with a high near 45.

Wednesday Night: A 20 percent chance of rain. Mostly cloudy, with a low around 39.

Thursday: A 30 percent chance of rain. Mostly cloudy, with a high near 52.

That is a much colder look from the NWS this afternoon for the short-term. Low to mid 40s for highs on Wednesday with rain? Brr.. That is cold!

I guess we will have to just sit back, buckle in, and see what eventually comes of all this, because right now I really don't know what to believe anymore..

lol.