Texas winter wx thread (2009-2010)

[WantSnow]

Uneventful in Plano, as usual.
I'm sure its on its way. Its mainly cloudy and its still 41 degrees

[vbhoutex]

these are dumb questions, but can the temp drop below the dewpoint? i always thought that when it was reached fog formed but I could be completey off. What needs to happen to get the dewpoint to drop?

I see 34 and snow at Breck with a dewpoint of 33. I understand the levels above all being cold enough to support snow. Are they just deeper cold layers than a 34 and rain?

There are no dumb questions here. We are fortunate to have both amatuer and pros alike who are very knowledgeable and willing to answer the questions. How do you think we learned/are learning what we know? Welcome to our site. We look forward to your participation!

[natlib]

The event is almost over in San Angelo as the temp never dropped below 37. Its been mostly light rain with only a couple of flurries. Overall a big bust since the original forecast was for 2 to 4 inches.

[srainhoutx]

agree getting to much warm air kicked around currently for this to be anything to huge at this point.. 1-2" likely widespread nothing more then 2 on avg... currently getting light snow here in w.falls

Eh, that's alright ... you're still batting .500!

This feature had a different approach with too much Pacific air entrained to be a bigger event msstateguy83. Keep an eye on next week though.

[Tejas89]

It appears the slowdown of this system gave DFW time for a warm-up this morning to about 4-5 over forecasted highs and effectively crippling any big snow chances. Steady rain and 41 in Arlington now. Intellicast radar really wants to bring that snow line in, but looks like late afternoon for much of the metroplex.

Bring on the real stuff next week!

[Ntxw]

agree getting to much warm air kicked around currently for this to be anything to huge at this point.. 1-2" likely widespread nothing more then 2 on avg... currently getting light snow here in w.falls

Eh, that's alright ... you're still batting .500!

This feature had a different approach with too much Pacific air entrained to be a bigger event msstateguy83. Keep an eye on next week though.

My fear for true arctic air is that it can be very shallow and once it moves through the atmosphere tends to dry a lot squashing any precip with it down south. I know there is a noisy SJT, but gfs have hinted at squashing the moisture away. Of course between now and then things can change as details are never known this far out. Just my two cents.

[srainhoutx]

Take a peek at the ensembles.

[msstateguy83]

yeah way its looking today might be a 'bust' with the high numbers had earlyer but
i think this is gonna be a LONG winter i mean just look @ the models lol and what
we have had already in some areas!

[txtiff]

Once again I can see and smell the smoke.....but no cigar

[aerology]

When the temp drops below the dew point the precip rate just goes up to compensate.

Have you ever noticed in the spring when the first masses of tropical air come into the mid-latitudes, having a dew point higher than the top soil temperature, how the thermal energy via condensation gets pushed into the soil until it is the same as the dew point.

You come out of the house in the morning, and the drive way and the garage floor is wet, from the thermal energy out of the air. This happens in the soil also, and farmers pay attention to it, to get ready to plant in the spring.

This is one of the warming effects, caused by the lunar declinational atmospheric tides as they bring in surges, of warmth and moisture in the spring. The dew point cannot get much above the soil temperatures, with out this condensation process pulling them up together.

[orangeblood]

change over to snow has occurred on the west side of Fort Worth. Melting on contact.

[shibumi]

When the temp drops below the dew point the precip rate just goes up to compensate.

Have you ever noticed in the spring when the first masses of tropical air come into the mid-latitudes, having a dew point higher than the top soil temperature, how the thermal energy via condensation gets pushed into the soil until it is the same as the dew point.

You come out of the house in the morning, and the drive way and the garage floor is wet, from the thermal energy out of the air. This happens in the soil also, and farmers pay attention to it, to get ready to plant in the spring.

This is one of the warming effects, caused by the lunar declinational atmospheric tides as they bring in surges, of warmth and moisture in the spring. The dew point cannot get much above the soil temperatures, with out this condensation process pulling them up together.

Sorry...doesn't work that way...the air temperature cannot go below the dew point when measured at the same point.....it is 100% saturated at that point...look at any sounding diagram and yu can see this....

not even going to get into the rest of this....

[TexasStorm]

Abiline

http://www.acu.edu/technology/is/departments/tech_supt/welcomecenter/index.html

[srainhoutx]

Looking ahead to next week...HPC Final Extended Disco...

EXTENDED FORECAST DISCUSSION
NWS HYDROMETEOROLOGICAL PREDICTION CENTER CAMP SPRINGS MD
158 PM EST TUE DEC 29 2009

VALID 12Z FRI JAN 01 2010 - 12Z TUE JAN 05 2010

TELECONNECTIONS WITH A NEGATIVE ANOMALY /THE POLAR VORTEX/ NORTH
OF THE NORTHWEST TERRITORIES OF CANADA COUPLED WITH A SLIGHTLY
RETROGRESSIVE POSITIVE MID-LEVEL ANOMALY /A CLOSED HIGH/ MOVING
FROM GREENLAND INTO NORTHEAST CANADA FAVOR A SLOW-MOVING VORTEX
NEAR THE NORTHEAST/ATLANTIC CANADA...A SOUTHERN STREAM NEAR THE
US/MEXICAN BORDER...AND RIDGING ACROSS WESTERN CANADA. THE MODELS
GENERALLY SHARE THESE LARGER SCALE FLOW IDEAS BUT CONTINUE TO
DIFFER WITH LESS PREDICTABLE SMALLER SCALE DETAILS.

OVERALL...FINAL HPC PRELIM MEDIUM RANGE PROGS FOR DAYS 4-7 REMAIN
PRIMARILY DERIVED FROM A 3-WAY BLEND OF THE 00 UTC GFS ENSEMBLE
MEAN...00 UTC ECMWF ENSEMBLE MEAN...AND THE 00 UTC ECMWF. THIS
SOLUTION MAINTAINS CLOSE HPC CONTINUITY...AND STILL BETTER ALLOWS
FOR LOWER HEIGHTS OVER THE WEST-CENTRAL US INTO EARLY NEXT WEEK AS
PER TRENDS FROM GFS/ECMWF/NAEFS ENSEMBLES VERSUS HIGHER VALUES AS
PER THE 00 UTC ECMWF/GFS. THIS WOULD FAVOR REINFOREMENT OF COLD
HIGH PRESSURE DOWN EXPANDING DOWN AND OUTWARD FROM THE CENTRAL
US...A SOLUTION THAT SEEMS MORE REASONABLE IN BETWEEN WRN NOAM
RIDGING AND THE POWERHOUSE/PERSISTENT CLOSED EAST-CENTRAL US
TROUGH POSITION. OVERALL...WE SEE MINIMAL COMPELLING REASON TO
CHANGE HPC CONTINUITY SIGNIFICANTLY AT THIS TIME AFTER
CONSIDERATION OF 12 UTC MODEL AND ENSEMBLE DATA.

THE PATTERN ACROSS THE EASTERN PACIFIC SHOWED THE BIGGEST
DIFFERENCE IN THE GUIDANCE FROM THE WEEKEND INTO EARLY NEXT WEEK.
RECENT GFS RUNS AND THE 00Z UKMET ARE ON THE FASTER EDGE OF THE
FULL ARRAY OF GUIDANCE WHILE THE 00Z ECMWF IS LESS PROGRESSIVE AND
OFFERS DEEPER LOW DEVELOPMENT. CONSIDERING WATER VAPOR LOOPS AND
SOLUTION SPREAD/UNCERTAINTY...PREFER OUR BLENDED SOLUTION WHOSE
MODERATE LOW DEVELOPMENTS ARE NEARER THE MIDDLE OF THE FORECAST
PROGRESSION ENVELOPE.

IN THE NORTHEAST...THE 00Z GFS/ECMWF ARE REASONABLY CLOSE IN
POSITION AND HAD ENSEMBLE SUPPORT. ITS CENTRAL PRESSURE IS AN
ISSUE AS THERE IS AT LEAST 20 HPA SPREAD AMONGST THE GUIDANCE...SO
OUR GUIDANCE BLEND INCLUDING A BIG CHUNK OF ENSEMBLE MEAN GUIDANCE
SEEMS REASONABLE AMID UNCERTAINTY WHILE STILL SHOWING A POTENT
SYSTEM. THE NEW 12 UTC ECMWF DOES TREND LOW ENERGIES MORE
OFFSHORE...BUT WILL HOLD THE COURSE WITH HPC LOW LOCATION IN THE
PROGS FOR NOW AS THE POTENT MEAN MID-UPPER LEVEL TROUGH POSITION
ALOFT IS STILL HELD WESTWARD IN MOST GUIDANCE.

IN THE SOUTHEAST...THE LAST FEW ECMWF RUNS ARE DEEP OUTLIERS WITH
MID-LEVEL HEIGHTS...FORCING 500 HPA HEIGHTS TO AROUND 5 STANDARD
DEVIATIONS BELOW NORMAL NEXT TUESDAY MORNING ACROSS
FLORIDA...WHICH IS IMPROBABLE. ANY OF THE OTHER PIECE OF 00Z
GUIDANCE SHOWS A MORE REASONABLE MID-LEVEL PATTERN ACROSS THIS
AREA AND WOULD BE MORE PREFERABLE. AS FOR THE LOW TRACK NEAR THE
GULF AND SOUTHEAST COASTS MID TO LATE PERIOD...USED THE 00Z
MULTI-MODEL ENSEMBLE CLUSTERING ALONG WITH OUR 3-WAY BLEND TO
MANUALLY DRAW A LOW AND TRACK WHICH WAS REASONABLY CLOSE...BUT
WEAKER THAN...THE 00Z ECMWF SURFACE LOW SOLUTION TO ACCOUNT WITH
ITS STRENGTH ISSUES ALOFT.

SCHICHTEL

[HockeyTx82]

Steady cold rain here in Denton.

[srainhoutx]

Good Long Range discussion from Brownsville this afternoon...snipet...

.LONG TERM (6 AM THURSDAY THROUGH TUESDAY)...WARMER CONDITIONS
EXPECTED THURSDAY BEFORE THE NEXT COLD FRONT MOVES THROUGH DEEP
SOUTH TEXAS THURS NIGHT. NOT MUCH IN THE WAY OF DEEP MOISTURE
PROGGED WITH FRONTAL PASSAGE SO WILL KEEP MENTION OF RAIN OUT OF
THE FORECAST. HIGH PRESSURE WILL BUILD INTO THE CWA FRIDAY AND
WEST TO NORTHWEST FLOW ALOFT SHOULD PROVIDE SUBSIDENCE ACROSS THE
AREA THROUGH SATURDAY. THE LATEST GFS MODEL RUN CONTINUES TO PROG
SOME SHOWERS DEVELOPING SAT NIGHT WITH LOW PRESSURE DEVELOPING
ACROSS WEST AND SOUTHWEST TX. SLIGHT CHANCE TO CHANCE OF RAIN
LINGERS SUNDAY THROUGH TUESDAY AS COLDER ADVECTS INTO THE LOWER
RIO GRANDE VALLEY SUN NIGHT INTO MONDAY ALLOWING OVERRUNNING TO
DEVELOP AND A 500MB TROUGH ACROSS THE SOUTHWEST U.S. AND NORTHWEST
MEXICO MONDAY MOVES EASTWARD ENHANCING THE OVERRUNNING CONDITIONS
THROUGH THE REST OF THE FORECAST PERIOD. &&

[orangeblood]

change over to snow has occurred on the west side of Fort Worth. Melting on contact.

[txagwxman]

Where's the beef...now the latest ECMWF is backing off the intensity for next week too. Where's the snow for DFW. Nice cold rain here in Houston...

[Tireman4]

Cold rain in Humble.

[Portastorm]

Where's the beef...now the latest ECMWF is backing off the intensity for next week too. Where's the snow for DFW. Nice cold rain here in Houston...

I wouldn't worry too much about that run. It is at odds with its three previous runs as evidenced if you go back and look at today's 0z and yesterday's 0z and 12z.

The GFS ensembles support the operational run and were in sync with the 0z Euro. The Canadian model also supported major-league cold next week.