Texas/New Mexico/Louisiana/Mexico Obs And Discussion Thread Part 6

[aggiegeog]

is it possible models couldn't handle the shallow cold air?

More than likely they are, but that will be almost impossible to determine until Wednesday.

[Srain]

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE HOUSTON/GALVESTON TX
250 PM CST MON MAR 2 2015

HOUSTON-TRINITY-MADISON-WALKER-SAN JACINTO-POLK-BURLESON-BRAZOS-
WASHINGTON-GRIMES-
INCLUDING THE CITIES OF...CROCKETT...TRINITY...GROVETON...
MADISONVILLE...HUNTSVILLE...SHEPHERD...COLDSPRING...LIVINGSTON...
CORRIGAN...ONALASKA...CALDWELL...LAKE SOMERVILLE...
COLLEGE STATION...BRYAN...BRENHAM...NAVASOTA
250 PM CST MON MAR 2 2015

...WINTER WEATHER POSSIBLE WEDNESDAY NIGHT INTO THURSDAY
MORNING...

A STRONG COLD FRONT WILL PUSH THROUGH THE AREA LATE WEDNESDAY
WITH FALLING TEMPERATURES BEHIND IT DUE TO A VERY COLD AIRMASS.
TEMPERATURES MAY REACH AND THEN DROP BELOW FREEZING DURING THE
EARLY MORNING HOURS THURSDAY. PRECIPITATION IS EXPECTED DURING
THIS TIME DUE TO LIFT FROM THE COLD FRONT AND A STRONG JET STREAM.
PRECIPITATION SHOULD BE ENDING LATER THURSDAY MORNING. BEFORE IT
ENDS...SOME PRECIPITATION MAY FALL WITH FREEZING TEMPERATURES
RESULTING IN A MIX OF RAIN AND FREEZING RAIN. AS THE COLD AIR GETS
DEEPER...THE RAIN AND FREEZING RAIN MAY TRANSITION INTO A MIX OF
SLEET. RIGHT NOW THE BEST TIME FOR FROZEN PRECIPITATION WILL BE
FROM 3 AM TO 9 AM THURSDAY MAINLY FROM A COLLEGE STATION TO A
LIVINGSTON LINE. AREAS FROM MADISONVILLE TO CROCKETT MAY HAVE A
HIGHER CHANCE OF A WINTTRY MIX OF PRECIPITATION SINCE TEMPERATURES
MAY FALL BELOW FREEZING SOONER.

OVERALL RAINFALL AMOUNTS WILL RANGE FROM 1 TO 2 TENTHS OF AN
INCH. ICE AND SLEET AMOUNTS WILL BE DIFFICULT TO DETERMINE SINCE
THERE ARE TIMING ISSUES WITH HOW LONG THE AREA WILL BE BELOW
FREEZING. AT THIS TIME ICE AND SLEET AMOUNTS SHOULD REMAIN UNDER 1
TENTH OF AN INCH. A WINTER WEATHER ADVISORY MAY BE NEEDED FOR
WEDNESDAY NIGHT INTO THURSDAY. OVERALL THE MAIN IMPACTS WILL BE
ICING OF ELEVATED SURFACES SUCH AS BRIDGES AND OVERPASSES. A TENTH
OF AN INCH OF ICE COULD STILL MAKE FOR HAZARDOUS TRAVEL CONDITIONS
ON ROADS.

 

[bubba hotep]

18z NAM is a train wreck

[NJ_Ken]

18z NAM is a train wreck

 

From the perspective of a snow and ice lover or from the perspective of a snow/ice hater?

[vwgrrc]

SPECIAL WEATHER STATEMENT

NATIONAL WEATHER SERVICE HOUSTON/GALVESTON TX

250 PM CST MON MAR 2 2015

HOUSTON-TRINITY-MADISON-WALKER-SAN JACINTO-POLK-BURLESON-BRAZOS-

WASHINGTON-GRIMES-

INCLUDING THE CITIES OF...CROCKETT...TRINITY...GROVETON...

MADISONVILLE...HUNTSVILLE...SHEPHERD...COLDSPRING...LIVINGSTON...

CORRIGAN...ONALASKA...CALDWELL...LAKE SOMERVILLE...

COLLEGE STATION...BRYAN...BRENHAM...NAVASOTA

250 PM CST MON MAR 2 2015

...WINTER WEATHER POSSIBLE WEDNESDAY NIGHT INTO THURSDAY

MORNING...

A STRONG COLD FRONT WILL PUSH THROUGH THE AREA LATE WEDNESDAY

WITH FALLING TEMPERATURES BEHIND IT DUE TO A VERY COLD AIRMASS.

TEMPERATURES MAY REACH AND THEN DROP BELOW FREEZING DURING THE

EARLY MORNING HOURS THURSDAY. PRECIPITATION IS EXPECTED DURING

THIS TIME DUE TO LIFT FROM THE COLD FRONT AND A STRONG JET STREAM.

PRECIPITATION SHOULD BE ENDING LATER THURSDAY MORNING. BEFORE IT

ENDS...SOME PRECIPITATION MAY FALL WITH FREEZING TEMPERATURES

RESULTING IN A MIX OF RAIN AND FREEZING RAIN. AS THE COLD AIR GETS

DEEPER...THE RAIN AND FREEZING RAIN MAY TRANSITION INTO A MIX OF

SLEET. RIGHT NOW THE BEST TIME FOR FROZEN PRECIPITATION WILL BE

FROM 3 AM TO 9 AM THURSDAY MAINLY FROM A COLLEGE STATION TO A

LIVINGSTON LINE. AREAS FROM MADISONVILLE TO CROCKETT MAY HAVE A

HIGHER CHANCE OF A WINTTRY MIX OF PRECIPITATION SINCE TEMPERATURES

MAY FALL BELOW FREEZING SOONER.

OVERALL RAINFALL AMOUNTS WILL RANGE FROM 1 TO 2 TENTHS OF AN

INCH. ICE AND SLEET AMOUNTS WILL BE DIFFICULT TO DETERMINE SINCE

THERE ARE TIMING ISSUES WITH HOW LONG THE AREA WILL BE BELOW

FREEZING. AT THIS TIME ICE AND SLEET AMOUNTS SHOULD REMAIN UNDER 1

TENTH OF AN INCH. A WINTER WEATHER ADVISORY MAY BE NEEDED FOR

WEDNESDAY NIGHT INTO THURSDAY. OVERALL THE MAIN IMPACTS WILL BE

ICING OF ELEVATED SURFACES SUCH AS BRIDGES AND OVERPASSES. A TENTH

OF AN INCH OF ICE COULD STILL MAKE FOR HAZARDOUS TRAVEL CONDITIONS

ON ROADS.

03022015 Valid 12Z Thursday prb_24hicez_ge_01_2015030300f060.gif

That map looks good

[aggiegeog]

From the perspective of a snow and ice lover or from the perspective of a snow/ice hater?

It continues to be extremely NW biased. It shows a Red River tracking storm though it seems everyone is pretty confident that this is more of a Central to Northeast Texas storm.

[bubba hotep]

From the perspective of a snow and ice lover or from the perspective of a snow/ice hater?

From every perspective, less than 0.10" qpf at DFW and all above freezing

[vwgrrc]

NWS held the special statement without upgrade.

[bubba hotep]

NWS held the special statement without upgrade.

Not surprising at all given the model trends today.

[bubba hotep]

Maybe some slit improvements with 00z NAM & GFS or maybe just model noise

[Srain]

Morning briefing from Jeff:

 

Strong arctic front to move across the region late Wednesday.

 

Dense sea fog has spread inland overnight with current visibilities in the 1/8^th to ½ mile range across the entire region. Fog will be slow to lift this morning and some locations may remain fairly foggy through 1000am-noon. Sea fog will plague the coastal waters and coastal counties nearly all day and into Wednesday as well.

 

Big story will be the arrival of another strong late season arctic air mass late Wednesday. Highs Wednesday will push into the mid 70’s with increasing chances for showers ahead of the frontal boundary. Front will reach College Station in the late afternoon and move off the coast by late evening. Strong cold air advection will result in temperatures rapidly falling into the 40’s and 30’s behind the boundary with gusty N winds. Rain will continue in the cold post frontal air mass.

 

Critical period continues to be Thursday morning as freezing surface temperatures move southward into the region and forecast soundings show some mid level cooling. Current model data suggests the freezing line will move southward to a College Station to Livingston line which would support a change of rain to freezing rain with possibly some sleet mixed in. Temperatures are only expected to fall into the 30-32 degree range which is very marginal for icing on bridges and overpasses especially after the warm Wednesday that will be had. South of this line precipitation will remain liquid with temperatures above freezing.

 

Very cold period Thursday-Saturday with a region wide freeze appearing likely on Friday morning. Temperatures could be well into the 20’s for many locations with average lows in the 25-30 degree range. Highs on Thursday will likely remain in the 30’s and in the mid 40’s on Friday under mainly cloudy skies.

 

Weekend forecast will feature a cold Saturday with highs only in the 40’s followed by a warm up on Sunday into the lower 60’s. GFS and ECMWF models are at odds on how to handle the next storm system over the Baja region this weekend with the ECWMF wet and colder for the weekend and the GFS drier. Low confidence in this part of the forecast with respect to both rain chances and temperatures.

 

[bubba hotep]

DFW might pull something out of this after all, some nice trends on the 00z Euro and 06z GFS. 12z runs could be interesting for sure.

[Srain]

Arctic front is moving S fairly quickly this morning. Temperatures are dropping into the low to mid teens across SE Wyoming/NW Nebraska at this hour.

 

[bubba hotep]

Arctic front is moving S fairly quickly this morning. Temperatures are dropping into the low to mid teens across SE Wyoming/NW Nebraska at this hour.

03032015 13Z_metars_den.gif

Nice, the DFW area isn't totally dependent on early cold, we could see some decent rates tomorrow evening, but the earlier the cold gets in the better.

[vwgrrc]

Nice, the DFW area isn't totally dependent on early cold, we could see some decent rates tomorrow evening, but the earlier the cold gets in the better.

good. But Where did u see the decent rate?

[bubba hotep]

12z NAM shifts south, 12z GFS slight shift, if Euro does the same then we might see an upgrade with the afternoon package

[Brent]

12z NAM shifts south, 12z GFS slight shift, if Euro does the same then we might see an upgrade with the afternoon package

 

Sign me up.

 

Oh yeah... weren't we gonna hit like 70 today? LOL

[aggiegeog]

12z NAM shifts south, 12z GFS slight shift, if Euro does the same then we might see an upgrade with the afternoon package

Looks like the models are converging on the earlier frontal passage and more moisture behind the front just as we expected.

[vwgrrc]

Looks like the models are converging on the earlier frontal passage and more moisture behind the front just as we expected.

and probably earlier arrival of cold front?

[aggiegeog]

and probably earlier arrival of cold front?

Yep, besides fronts coming down from the NE all Arctic fronts that I remember move south faster than modeled.

[vwgrrc]

Looks like Steve doesn't really buy the changes: 

 

...looking at the new data sets, there does not seem to be any major changes from yesterday's outlook. The majority of the precipitation should be just cold rain. By the time it gets cold enought to change to sleet and freezing rain, the precipitation will be winding down....

[wxmx]

I may hit upper 80s tomorrow, then down to upper 30s 18 hours after, not too shabby.

 

I may hit my first freezing temp of the winter Friday morning, and the first recorded in March in the 21 years I have lived here.

 

It may not have been a classical Niño, but the 4 month period from Nov-Feb, recorded 44 rain days (almost 10" fell), the most in the last 30 years (36% of the days had rain, and most of the time was day long rain, though mostly drizzle and light rain). The 2nd in the list for the same period is 2014, with 28 days (8.8"), then back to 1987. Average for the period is around 3.5", so it's almost 300% above average. CAD events galore with stratiform precipitation with some orographic enhancement. No end on sight.

 

It appears that the March pattern will be more Niño like, with higher heights in Canada and northern US, and lower heights over the Sern US and MX.

[wxmx]

Looks like Steve doesn't really buy the changes: 

 

...looking at the new data sets, there does not seem to be any major changes from yesterday's outlook. The majority of the precipitation should be just cold rain. By the time it gets cold enought to change to sleet and freezing rain, the precipitation will be winding down....

Not according to the latest guidance...the majority of the precipitation is after going below freezing...and models are also moister. Sleet would be the main ptype. Being an arctic outbreak, the column of air may support snow a little sooner than models depict.

[Srain]

I just got home and have looked at the various raw data and computer guidance for IAH on N. It's beginning to look like we may have some issues just N of I-10 mainly N of the W of the Beltway 8 areas and the I-35 Corridor on S to College Station into Conroe certainly look worrisome for a round of freezing rain and  heavy sleet possibly ending as some snow during the day on Thursday. That is a powerful Western storm brewing with lots of tropical moisture streaming NE and the Arctic front is moving quickly through Kansas at this hour.

 

[bubba hotep]

Based on the 12z data, I would bet on, at a minimum, the northern two rows of counties getting upgraded to an advisory.

[bubba hotep]

Saddle up one last time!

[aggiegeog]

18Z RGEM looks like heavy sleet with snow on the north of I-30 in the Metroplex around midnight and heavy freezing rain around Austin at the same time and heavy sleet with snow north of I-30 in Northeast Texas in the early morning hours. Amounts are 1-3" of snow north of a line from Texarkana to Midland, around 1" of sleet from San Angelo to just south of Texarkana and .25-.5" of freezing rain from Kerrville to south of Tyler.

[bubba hotep]

18Z RGEM looks like heavy sleet with snow on the north of I-30 in the Metroplex around midnight and heavy freezing rain around Austin at the same time and heavy sleet with snow north of I-30 in Northeast Texas in the early morning hours. Amounts are 1-3" of snow north of a line from Texarkana to Midland, around 1" of sleet from San Angelo to just south of Texarkana and .25-.5" of freezing rain from Kerrville to south of Tyler.

How has the RGEM done in Texas this winter? I haven't looked at it once this winter. IIRC, people seem to think it produces some of the more accurate snow maps.

18z NAM 4k looks to be around 0.5" frozen qpf across the eastern half of the metroplex.

[Captmorg70]

I feel like the RGEM did well with everything last week. It's a little high on the QPF but hit the Monday and Friday storms well

[aggiegeog]

I feel like the RGEM did well with everything last week. It's a little high on the QPF but hit the Monday and Friday storms well

Completely agree, it seems to handle the placement of systems, precip timing and types very well. It does overdo precip at times. It also has easy to access qpf maps for each precip type.