December: Warm Days & Cool-Foggy Nights To End 2011

[srainhoutx]

Meh, cold weather lovers shouldn't worry too much on December 13th. We've got a couple of months to go before the weather flips back into heading toward a spring time pattern. Just a hunch, but be careful what you wish for. Those of us that lived here in 73, 83, and 89, among other years, know things can get down right brutally cold here in SE TX. Think of those poor snow lovers along the Mid Atlantic and the NE. They are already cancelling winter since we reached freezing at IAH before NYC and DC!...

Oh and for the record, the first 11 days in December are well below average climo wise for Texas and Houston.

[srainhoutx]

We have an active period ahead and today will be the quiet one for most of the next 7 days. The SPC has a Slight Risk for severe storms for parts of Central and NE TX on Wednesday. An upper air disturbance will begin moving NE from S CA/AZ tonight bringing mountain snows to the higher elevations with rain/freezing rain chances into the Central Plains. Further S, thunderstorms with damaging winds and even some hail across portions of Central/NE TX are possible. A Pacific front should slide S and stall near the coast on Thursday allowing for over running rain chances through Saturday.

Another more potent upper air disturbance will dive S into the Desert SW and meander over the weekend before ejecting E. The timing of this second disturbance is in question, but all guidance suggest a closed cold core low will trek across N MX into TX. At the same time a powerful northern stream storm system will trek E near the Canadian/US border dropping some arctic air S. As the SW storm wraps up and begins to slowly move E, that cold air will spill S through the Plains. Wintry mischief is looking likely for the Southern Rockies. As the system enters TX, rains and evn some heavy storms are possible in the warm sector. Wintry mischief looks possihble for parts of W/The Panhandle/N Central And N TX as the upper low passes to the E. While it is still diffiicult to determine the track of this feature, early indications are it may be a bit further S. Cold air with a strong front will be associated with this storm and as of now it appears that we are once again moving into a rather cold pattern.

The sub tropical jet remains noisy as well as storms moving across the N Pacific. The pattern shows no real sign of relaxing, so it appears we will remain in an unsettled situation for some time on into the Christmas Holiday period.

[wxman57]

The overnight run of the GFS is quite warm for the next 8 days. Temps from the 50s to the 70s. Note that the GFS, Euro and Canadian all have different solutions for handling the upper low/trof in the SW U.S. over the coming week. However, none of them shows a significant cold air intrusion into Texas next week. Significant meaning widespread freezing temps.

[wxman57]

12Z GFS is in. Cool, cloudy with light rain this weekend. Warm-up Monday then another front Tuesday. It's cooler than the 06Z run for next week. Nothing extreme. I think it may be a bit warmer this weekend than the GFS is indicating in the 2-meter temps below:

[srainhoutx]

HPC Final Update suggests a lot of uncertainty in the medium range. It does appear we are headed toward a very damp and progressive pattern of a parade of storms trekking across the area with the split flow pattern. The N Pacific remains very active as well as a noisy sub tropical jet. The very un La Nina pattern appears to be locked in place for the foreseeable future...


EXTENDED FORECAST DISCUSSION
NWS HYDROMETEOROLOGICAL PREDICTION CENTER CAMP SPRINGS MD
1251 PM EST TUE DEC 13 2011

VALID 12Z FRI DEC 16 2011 - 12Z TUE DEC 20 2011


PRELIMINARY UPDATE...

USED A NEAR EVEN BLEND OF THE 00Z/13 DETERMINISTIC ECMWF AND ECENS
MEAN TO UPDATE THE PRELIMINARY FRONTS AND PRESSURES FOR DAYS 3
THROUGH 7. THIS COMBINATION OF GUIDANCE IS A BEST FIT TO THE
CLUSTERING OF THE GLOBAL MODEL SOLUTIONS FOR EACH SIGNIFICANT
SYNOPTIC SHORTWAVE ACROSS CENTRAL NORTH AMERICA AT THE MEDIUM
RANGE. THE BACKBONE OF THE PATTERN IS NOT EXPECTED TO
CHANGE...WITH SPLIT FLOW OVER THE WEST...AND THE REUNION OF THE
STREAMS NEAR THE MID ATLANTIC REGION. THE SUBTROPICAL RIDGE OVER
THE SOUTHEAST GETS TEMPORARILY SQUASHED AS AN EXTRA MASSIVE SLUG
OF ENERGY ROLLS ACROSS THE GREAT LAKES AND SAINT LAWRENCE VALLEY
MID PERIOD. IT APPEARS THE SOUTHWESTERN TROUGH WILL FINALLY KICK
INTO THE SOUTH CENTRAL STATES LATE DAY 6...REACHING THE TENNESSEE
VALLEY BY DAY 7.


FINAL...

MADE ONLY COSMETIC CHANGES TO THE UPDATE PACKAGE FOR THE FINAL
ISSUANCE. THE 12Z/13 GFS HAS TRENDED MUCH CLOSER TO THE 00Z/13
EUROPEAN CENTRE SUITE...WITH THE HANDLING OF BOTH THE NORTHERN AND
SOUTHERN STREAM WAVES. IT IS SIGNIFICANTLY SLOWER EJECTING THE
SOUTHWESTERN LOW. THE GEM GLOBAL...ON THE OTHER HAND...IS ABOUT
AS FAST AS THE 00Z/13 GFS WITH THIS SYSTEM...WITH THE UKMET SLOWER
THAN ALL THE GUIDANCE. THE MIDDLE GROUND AGREEMENT BETWEEN THE
NEW DETERMINISTIC GFS AND THE 00Z/13 EC GUIDANCE LOOKS TO BE THE
STRONGEST BET FOR THIS FORECAST PERIOD.

[biggerbyte]

Again, don't worry about it, Arizona. Focus on the forecast for the next few days. Anything else is pure speculation, and the flip flopping will drive you up the wall. How many days is Christmas from today? Come on now. Breathe, grasshopper.

[wxman57]

The bitter cold air doesn't exist right now, even in Canada. Temps are well above normal in Canada. Until that changes, we won't see any down here.

[srainhoutx]

Foggy conditions and warm temps are on tap for the day. Showers and a few heavy storms are possible during the overnight hours as a Pacific cold front slowly sags S through the area tomorrow. The SPC has removed the Slight Risk for severe storms across the Central Texas Region for today. Storms should not be severe in our area, but I wouldn't rule out a couple of gusty storms with heavy rainfall during the overnight hours. Over running conditions should set up as the front stalls near the coast. We'll need to monitor just how far the front pushes S and there could be some big temp differences from S to N across the area if the front does not push off the coast. Rain chances look to continue into Saturday as embedded short wave energy rides along the southern jet. Another upper air disturbance will drop S to our W into S CA/Baja and keep us under a SW flow aloft. Foggy conditions appear likely for Sunday into Monday before rain chances again increase as that upper low ejects N and E. Once again heavy rainfall and some storms chance may enter the picture as another front heads S late on Monday into Tuesday. The pattern will wash, rinse and repeat next week with yet another upper air disturbance dropping into the SW. The active pattern looks to continue on through the Christmas Holiday period.

[wxman57]

A certain person here might like to know that the overnight GFS run has a cold front coming through Houston late on the 23rd, dropping low temps to the mid 20s with highs in the low 40s on Christmas. I wouldn't put that in my forecast yet, though.

[srainhoutx]

A certain person here might like to know that the overnight GFS run has a cold front coming through Houston late on the 23rd, dropping low temps to the mid 20s with highs in the low 40s on Christmas. I wouldn't put that in my forecast yet, though.

I also would also mention that there are some hints of a big pattern change as we head toward the New Year, but I wouldn't forecast that yet either...

[srainhoutx]

The 12Z WRF/NAM suggests the front will stall just offshore and a coastal low/trough begins to develop near the Lower/Middle TX Coast on Friday with over running light rain and drizzle...

[srainhoutx]

Morning e-mail just received from Jeff:

Increasing chances for more needed rainfall over the next several days!

Current issue remains the very dense sea fog bank that has formed over the upper TX coastal waters. Warm moist air flowing over the chilled near shore waters has produced an extensive bank of sea fog along much of the LA coast into SE TX. SW edge of this fog is along a line from roughly Galveston to South Houston to near Tomball and eastward with visibilities running .25 of a mile or less along the coast and in the bay. Low level winds are expected to turn more SE to S today and this may help reduce the fetch of chilling time and saturation of the moist marine air over the colder waters and help break up the fog bank. Not overly convinced this will happen, and even if the extensive bank breaks up, expect smaller pockets of very dense fog to continue into Thursday.

Next front and storm system will move into the area late tonight-Friday morning as this highly active weather pattern continues. Very slow moving frontal boundary will arrive into our northern counties by sunrise on Thursday and very slowly cross the area during the day…taking all day if not into the evening to move to the coast. Moisture will pool along and behind the front and expect widespread showers and some thunderstorms spreading from north to south across the region on Thursday. Greatest rain chances may actually come in the colder air north of the front and ahead of the 850mb front where best lift will be found and think Thursday night into Friday morning will feature the highest chances as the next short wave in the SW US moves into the plains adding additional dynamics across the area. A few strong storms will be possible, but the severe threat looks low at this time. Rainfall amounts of .5 to 1.5 inches will be common over the region.

Active SW flow aloft will continue post front and upglide pattern of warm moist air atop the dense cold surface air will commence by later Friday. Isentropic lifting may be enough to continue to generate light rain Friday night and Saturday in the cold air. Will hold temperatures in the 50’s all day Saturday as clouds, drizzle and light rain stunt any warming trend. Overall looks to be shaping up for another cold and dreary weekend and rain chances may need to be raised even more toward the 50-60% range per latest GFS MOS guidance.

Models move the front back northward Sunday as a warm front, but they tend to mix warm front too fast northward especially if clouds and light rain is falling north of the boundary. This is in response to yet another upper level trough digging into the SW US. Temperatures on Sunday will be tricky with areas south of the warm front warming into the 70’s and areas north of the boundary holding in the 50’s. This storm system will eject eastward into the plains on Monday and with it a rapidly moving Pacific cold front. Favorable moisture and dynamics appear in place to produce a round of fast moving thunderstorms late Sunday into Monday. Depending on where the warm front ends up Sunday night we could see another…but shorter…period of dense sea fog near the coast late Sunday.

Clearing and colder Monday evening through next Wednesday as the upper level flow turns more zonal (WNW) instead of the moist SW upper flow of late. However the upper pattern continues to look progressive and active on the long range charts with additional storms system possible toward the end of next week around Christmas.

[srainhoutx]

This is still a ways out, but the 12Z GFS is beginning to latch on the idea the Euro suggested a couple of day ago regarding a storm track a bit further S with the Monday event. It will be interesting to monitor this storm system as it has a bit better potential to bring a variety of weather across Texas Sunday into Monday night.

[srainhoutx]

The 12Z GFS Ensembles also suggest a combination of potential wintry mischief and rains further S across Texas early next week...

[wxman57]

We're still just looking at a chance of snow in the TX Panhandle and northern OK early next week. Nothing even remotely close to Houston. Euro, Canadian and GFS are all in good agreement on that issue now. There just isn't any new Canadian air coming south, and temps in western Canada are above normal.

[srainhoutx]

Still a will it or won't it discussion regarding sudden stratospheric warming, occasional KHOU poster wxmx thick in it, at another forum, so maybe mid January will see a frigid change. Terms about mountain torques, 1 mb and 60 mb temp changes, wind vector chambers, I see the main points only through a foggy glass.

Just wait and see...

Yep. It's a wait and see game at this point. That said some hints are showing up in the operational Euro in la la land over Eurasia...and the Euro MJO analysis suggests the Indian Ocean may become active. Some folks often forget that what happens elsewhere across the globe has effects in our back yard down the road, so to speak...

[srainhoutx]

HPC Final Update spells all all the issues and impacts early next week...and the fact that any cool down will be short lived...

EXTENDED FORECAST DISCUSSION
NWS HYDROMETEOROLOGICAL PREDICTION CENTER CAMP SPRINGS MD
229 PM EST WED DEC 14 2011

VALID 12Z SAT DEC 17 2011 - 12Z WED DEC 21 2011

THE LONGWAVE PATTERN WILL CONSIST OF A BROAD AREA OF ABOVE NORMAL
HEIGHTS FROM THE PACIFIC NW AND ADJACENT WATERS EWD TO THE GREAT
LAKES REGION THEN SWD INTO THE CENTRAL APPALACHIANS. HEIGHTS WILL
AVERAGE BELOW NORMAL ACROSS MOST OF NRN CANADA YIELDING A VERY
POSITIVE NAO.

FINAL PROGS STAYED WITH THE BLEND OF 70% 06Z GEFS AND 30% 00Z GEFS
MEAN. IN OUR UPDATE...WE NOTED THAT MOST OF THE NRN STREAM
ENERGY IN THE GEFS MEAN THIS PERIOD WAS STAYING ABOVE LATITUDE
40N. ALSO...WE NOTED A TREND IN RECENT GFS RUNS FOR A TRAILING
TROF/SHEAR AXIS BEHIND THE EJECTING SWRN CONUS LOW TO BE WEAKER.
THEREFORE...WE THOUGHT THAT THE SLOW SIDE OF THE ENVELOPE OF
EJECTING SOLUTIONS MIGHT BE MORE ACCURATE. AT FIRST THE 12Z/14
UKMET/GFS SEEMED TO CONFIRM THIS REASONING.

THE MAIN MEDIUM RANGE FORECAST CHALLENGE HINGES ON TIMING THE
EJECTION OF A CLOSED LOW OUT OF THE SOUTHWEST...ESPECIALLY
CONSIDERING NRN STREAM INTERACTION FROM THE CENTRAL US. THE 00Z
ECMWF/CANADIAN WERE QUICKER TO EJECT THE LOW ON MON/DAY
5...ENTRAINING NRN STREAM ENERGY INTO IT AS THE ASSOCIATED SFC LOW
DEEPENED THROUGH THE GREAT LAKES AND POINTS EWD TUE/DAY 6. THE 00Z
GFS/UKMET AND ESPECIALLY THE 06Z/12 GFS WERE SLOWER EJECTING THE
UPPER LOW. THE 00Z GFS WAS IN STEP WITH THE BULK OF THE 12Z/13
FULL ENSEMBLE SUITE AND THE MAJORITY OF THE 00Z GEFS MEMBERS. IT
SHOWED A NRN STREAM SHORTWAVE OUTRUNNING THE WEAKENING ERSTWHILE
SWRN CLOSED LOW...RESULTING IN A FLATTER PATTERN ACROSS THE
MID-ATLANTIC. AT THE TIME WE PREFERRED TO STAY JUST A BIT SLOWER
THAN 00Z GFS CONTINUITY WITH THE UPPER LOW AT LEAST THRU DAY 5.
THE 12Z GFS HAS EXCELLENT TIMING IN ITS CONTINUITY ON THE SWRN
CLOSED LOW FROM ITS 06Z RUN...AND IS SUPPORTED BY THE 12Z UKMET
THRU DAY 5.

HOWEVER...THE FASTER 00Z/14 ECMWF SOLUTION IS NOT DEAD YET!
CRUCIAL TO THE INTERACTION OF THE SRN STREAM SYS WITH NRN STREAM
ENERGY IS THE SHARPENING OF A SHORT WAVE RIDGE ALONG 130W SUN EVE.
THE NON GFS MODELS SHARPEN UP SHORTWAVE ENERGY ON THE E SIDE OF
THIS RIDGE FAR ENOUGH S TO INTERACT WITH THE EJECTING SRN STREAM
LOW WHILST THE 12Z GFS DOES NOT. THE 12Z ECMWF JOINS THE UKMET AND
CANADIAN IN BECOMING OVER A HALF DAY FASTER BY TUE DAY 6 IN
BRINGING REMNANTS OF THE SRN STREAM CLOSED LOW OUT. THE NEW UKMET
BEGINS TO PULL AWAY FASTER FROM THE GFS LATER DAY 5 AS IT SHOWS
MORE NRN STREAM INTERACTION FROM THE CENTRAL PLAINS/ROCKIES. THE
NEW CANADIAN STARTS OFF WITH THE SAME TIMING AS THE GFS DAYS 3-4
BUT USES NRN STREAM ENERGY TO BECOME EVEN FASTER THAN THE OLD GFS
RUN FOR TUE-WED DAYS 6-7.

AS THE CLOSED UPPER LOW COMES OUT OF THE SWRN STATES IT SHOULD
GENERATE A MAJOR PCPN EVENT FOR MUCH OF TX/OK/AR. THIS SYS HAS
POTENTIAL TO BRING SIGNIFICANT DROUGHT RELIEF TO PORTIONS OF OK
AND AND NW CENTRAL TX. AS THE SYS EXITS THE SRN PLAINS RAIN COULD
END AS A COUPLE INCHES OF WET SN IN OK.
THE PROGRESSIVE NATURE OF THE FLOW WILL NOT PERMIT CONDS TO STAY
VERY COLD FOR LONG AT ANY ONE LOCATION. THE NORTHEAST MAY SEE
COLD SPELLS OVER THE WEEKEND AND AGAIN AROUND WED. THE WEST WILL
BE CHILLY EARLY NEXT WEEK.

[JackCruz]

December 26th and 27th

[srainhoutx]

There is some chatter this afternoon from San Angelo and the Panhandle NWS offices regarding some wintry mischief for Monday into Tuesday. The GFS seems to be the current thinking with all the WFO's across the Lone Star State due to the stronger, more cut off solution via that model as well as a few others. As we have seen repeatedly in this pattern, the guidance struggles beyond the 3 day period, so expect changes. As for tonight, the area is fairly capped and heavy rain chances are looking a bit less likely. Currently some storms are firing near N Texas and Oklahoma along a dry line. An upper vort is approaching the area from the W and the Pacific front is entering the Panhandle. We'll need to watch how things develop over Central Texas tonight and if the front is slower or stalls to our N, then warm temps can be expected tomorrow. Over running showers and drizzle still appear likely once the front slowly sags S.

[biggerbyte]

Guys, these popups are becoming a bigger problem around here. I visit a lot on my iPhone, which has no way to block them. BELO is destroying the experience again.

Heads up..

Edit to say I found an ad block option in this mobile browser. We will see if it helps any.