TX winter wx thread: Spring-like pattern

[Ed Mahmoud]

6Z GFS sees a possibility of frozen precip a week from this Friday just North and West of HOU!

[Ed Mahmoud]

Where is EWG?

12Z GFS suggests chance for freezing rain early Monday morning. Wouldn't take much to cancel school in the Hurst-Euless-Bedford ISD. My older sister lives in that school district, and owns the mineral rights under her 1/3rd acre suburban home, and just signed a lease with Dale Operating Co. of Fort Worth to directionally drill a Barnett Shale gas well under her neighborhood.



I will say, point forecast numbers from the 12Z GFS have 2 meter temps above freezing, so no point getting too enthusiastic yet.

[southerngale]

A week from this Friday.... that's 10 days away. I predict highs lows in the 50's and highs in the 70's, without consulting a map.
j/k - but I have given up on seeing frozen precip (well, snow) this season. I'm optimistically rooting for drier weather so we can get our work outside completed.
I would still be pleasantly surprised if it miraculously snowed though!
ha

It did hit 30F this morning. I am thinking this was probably my last freeze of the season. It'll be March in a few days.

[Jagno]

Southerngale; I'm just east of you and we had 16 degree temps on March 01, 1980. I remember because that was my wedding so it's not totally out of the possibility to see freezing temps in March. Of course we'd both said it would be a cold day in ...............never mind. LOL

[Ed Mahmoud]

Does 0Z GFS suggest wintry precip for DFW area Monday?


0Z Canadian seems to suggest close, but no cigar, as only light precip remaining when cold air arrives.



DGEX says no, and raw GFS numbers from my AccuWx PPV site says DFW area stays above freezing, so it looks like the kids have school next Monday, but I will keep a close watch.


0Z GFS also implies almost all precipitation is post-frontal, reducing the risk for severe weather in SE Texas, despite SPC having HOU area in a Day 4 and Day 5 outlook area.

[Ed Mahmoud]

Freezing/Frozen Precip Northwest of DFW Monday Morning?


Note 0Z WRF shows 850 mb freezing line passing Wichita Falls around midnight Sunday night/Monday morning, and six hours later approx. one half inch (about 13 mm) of precip has fallen.

0Z GFS similar on passage of 850 mb freezing isotherm, but basically cuts off the precip about the same time.


The 12Z WRF is starting to trickle out now, be exciting to see what it shows.

[Ed Mahmoud]

Freezing/Frozen Precip Northwest of DFW Monday Morning?


Note 0Z WRF shows 850 mb freezing line passing Wichita Falls around midnight Sunday night/Monday morning, and six hours later approx. one half inch (about 13 mm) of precip has fallen.

0Z GFS similar on passage of 850 mb freezing isotherm, but basically cuts off the precip about the same time.


The 12Z WRF is starting to trickle out now, be exciting to see what it shows.

¡YES! ¡YES! ¡YES!


The new 12Z WRF shows the 850 mb freezing line passing DFW around 6 am Monday morning, and between then and noon, a quarter inch (over 6 mm) of precip falls.



WRF also shows precip ahead of the cold front in SE Texas, increasing the chance of tornadic storms.

[gboudx]

¡YES! ¡YES! ¡YES!


The new 12Z WRF shows the 850 mb freezing line passing DFW around 6 am Monday morning, and between then and noon, a quarter inch (over 6 mm) of precip falls.



WRF also shows precip ahead of the cold front in SE Texas, increasing the chance of tornadic storms.

What do you think this would be? Freezing rain? Sleet? Mix?

[Ed Mahmoud]

¡YES! ¡YES! ¡YES!


The new 12Z WRF shows the 850 mb freezing line passing DFW around 6 am Monday morning, and between then and noon, a quarter inch (over 6 mm) of precip falls.



WRF also shows precip ahead of the cold front in SE Texas, increasing the chance of tornadic storms.

What do you think this would be? Freezing rain? Sleet? Mix?

Just cheated by looking at 2 m temps from AccuWx PPV site, both (for now) showing temps above freezing, so maybe snow or sleet. Maybe. I'll feel better if the next few model runs trend colder, but this year the models have had an ugly habit of trending warmer as an event approaches.

[gboudx]

Just cheated by looking at 2 m temps from AccuWx PPV site, both (for now) showing temps above freezing, so maybe snow or sleet. Maybe. I'll feel better if the next few model runs trend colder, but this year the models have had an ugly habit of trending warmer as an event approaches.

Yep. Which is why I won't hold my breath.

[Extremeweatherguy]

The 12z GFS looks interesting both early AND late next week with some possible winter precipitation in parts of the state. Also, it is showing a back-to-back freeze here in Houston (IAH) next Friday morning and Saturday morning...which would definitely be noteworthy for March. We will just have to watch things closely and see what happens..

[Extremeweatherguy]

The 18z GFS is a bit interesting. It is showing some wrap-around precipitation occurring in our general vicinity next Monday evening/Tuesday morning behind the cold front (with cold air is in place overhead). If we do see some light wrap-around precipitation, then the upper levels will likely be cold enough for some mixing..

http://www.nco.ncep.noaa.gov/pmb/nwprod ... p_072l.gif
http://www.nco.ncep.noaa.gov/pmb/nwprod ... p_078l.gif
http://www.nco.ncep.noaa.gov/pmb/nwprod ... p_084l.gif

http://www.nco.ncep.noaa.gov/pmb/nwprod ... p_072l.gif
http://www.nco.ncep.noaa.gov/pmb/nwprod ... p_078l.gif
http://www.nco.ncep.noaa.gov/pmb/nwprod ... p_084l.gif


What continues to look much more interesting than the Monday/Tuesday event though, is what may occur later next week. The 18z GFS continues to show a setup possibly capable of a more widespread mixing threat in parts of SE and E Texas...

http://www.nco.ncep.noaa.gov/pmb/nwprod ... p_144l.gif
http://www.nco.ncep.noaa.gov/pmb/nwprod ... p_150l.gif
http://www.nco.ncep.noaa.gov/pmb/nwprod ... p_156l.gif
http://www.nco.ncep.noaa.gov/pmb/nwprod ... p_162l.gif

http://www.nco.ncep.noaa.gov/pmb/nwprod ... p_144l.gif
http://www.nco.ncep.noaa.gov/pmb/nwprod ... p_150l.gif
http://www.nco.ncep.noaa.gov/pmb/nwprod ... p_156l.gif
http://www.nco.ncep.noaa.gov/pmb/nwprod ... p_162l.gif

..Definitely something to keep a close eye on!

BTW - - The one bit of good news out of this is that surface temperatures are expected to remain just above freezing (especially in and around the Houston area) during both of these times. That means that no major travel issues would be expected IF any kind of mixing or changeover scenario WERE to play out.

[Ed Mahmoud]

WRF would appear to show winter weather Monday in DFW, with sub-540 dm thicknesses and sub freezing 850 mb temps with precip, but raw WRF numbers off my PPV AccuWeather site shows temps in the mid 40s.


Maybe the March sun through clouds is strong enough to pull that off?

WRF loop

[jasons2k]

AREA FORECAST DISCUSSION...UPDATE AVIATION
NATIONAL WEATHER SERVICE HOUSTON/GALVESTON TX
520 AM CST SAT MAR 1 2008

.DISCUSSION...
SLOWLY WEAKENING SHOWERS ACROSS PORTIONS OF OUR NORTHEAST COUNTIES CONTINUE
TO SAG SOUTHWARD. EVEN THOUGH WATER VAPOR SATELLITE IMAGERY SHOWS A
MUCH DRIER AIRMASS SAGGING INTO SOUTHEAST TEXAS FROM THE NORTH...DECIDED
TO ADD 20% POPS AREAWIDE TODAY DUE TO RESIDUAL BOUNDARIES FROM THE CURRENT
ACTIVITY IN COMBINATION WITH AFTERNOON HIGHS IN THE UPPER 70S. WOULD
NOT BE AT ALL SURPRISED IF THE NEXT SHIFT IS ABLE TO REMOVE ALL POPS
FROM TODAY`S FORECAST. MOISTURE BEGINS INCREASING AREAWIDE ON SUNDAY
AS A DISTURBANCE APPROACHES THE AREA FROM THE WEST. WILL CARRY LOW POPS
DURING THE DAY...THEN INCREASE THE RAIN CHANCES UP NORTH AS THE EVENING
AND OVERNIGHT HOURS PROGRESS DUE TO AN APPROACHING COLD FRONT AND INCREASING
INSTABILITY. THINGS GET CRANKING SHORTLY BEFORE SUNRISE...AND HAVE INTRODUCED
SEVERE IN THE FORECAST FOR MONDAY MORNING AS THE STRONG COLD FRONT SWEEPS
THROUGH OUR AREA. DYNAMICS ARE LOOKING INCREASINGLY FAVORABLE FOR STRONG
TO SEVERE STORM DEVELOPMENT...WITH LOW LI AND WET BULB ZERO VALUES ALONG
WITH HIGH HELICITY VALUES AND INCREASING CAPES. STRONG DAMAGING WINDS...LARGE
HAIL AND ISOLATED TORNADOES WILL BE THE SEVERE WEATHER THREATS. WINDS
WILL SHIFT TO THE NORTHWEST AND TEMPERATURES WILL FALL RAPIDLY BEHIND
THE FRONT. WILL CARRY LOWER CHANCES OF MAINLY SHOWERS FOR MONDAY AFTERNOON...BUT
ISOLATED THUNDER CANNOT BE RULED OUT AS THE MAIN TROUGH AXIS LAGS A
LITTLE BEHIND THE FRONTAL PASSAGE. WE`LL MOST LIKELY NEED A WIND ADVISORY
THE COASTAL COUNTIES AND POSSIBLY SOME COUNTIES FURTHER INLAND AFTER
THE FRONTAL PASSAGE. ALL RAINS WILL COME TO AN END BY SUNSET. DRY WEATHER
AND COOLER TEMPERATURES WILL THEN PREVAIL TUESDAY AND TUESDAY NIGHT.
A WARMUP WILL BEGIN ON WEDNESDAY...AND LOW PRECIP CHANCES WILL COME
BACK INTO THE FORECAST BEGINNING WEDNESDAY NIGHT. HAVE BROUGHT LOW POPS
BACK INTO THE FORECAST FOR THURSDAY AS SOME UNCERTAINTY EXISTS WITH
THE NEXT SYSTEM. WILL THE NEXT LOW CLOSE OFF AND SINK SOUTHWARD INTO
MEXICO PER THE ECMWF...OR WILL IT BE MORE PROGRESSIVE AND MOVE EAST
OF OUR AREA PER THE GFS? OUR FORECAST FOR THE SECOND HALF OF THE WEEK
IS SUBJECT TO SIGNIFICANT CHANGE.

[Extremeweatherguy]

Latest Shreveport, LA AFD (which includes places such as Lufkin)...

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SHREVEPORT LA
224 PM CST SAT MAR 1 2008

.DISCUSSION...
BROAD UPPER RIDGING FOR TIME BEING...WITH MODERATE CUMULUS
DEVELOPMENT. CLOUDS A BIT DENSER THIS AFTN NEAR RED RIVER VALLEY...
WITH BOUNDARY RETREATING NORTHWARD. LOOKING AT A PARTLY CLOUDY
EVENING WITH SOUTH BREEZE MAINTAINING AS LOW LEVEL WINDS FIELDS ON
THE INCREASE. OVERNIGHT LOWS IN THE UPPER 50S WILL PREVAIL...BUT A
FEW SPOTS MAY REMAIN ABOVE THE 60 DEGREE MARK. LEAD SHORT WAVE WILL
INTERACT WITH INCREASING WARMTH AND INSTABIITY...BUT ONLY MARGINAL MOISTURE...
FOR SUNDAY AFTN. WILL COVER WITH LOW POPS FOR CONVECTION SUNDAY
AFTN...WITH MAIN ACTIVITY PROBABLY NOT FIRING UP UNTIL AT LEAST
MIDNIGHT. DEEPENING UPPER LOW TO CUT OFF FROM MAIN FLOW...WITH
TIGHT PRESSSURE GRADIENT LEADING EDGE. A SITUATION OF STRONG WINDS...WITH
A LIKELYHOOD OF VERY HEAVY RAINFALL...AND QUITE POSSIBLY A SEVERE
STORM OUTBREAK...WITH OMINOUS 60 TO 70 KT LOW LVL JET ON
TAP...EAST TX SUNDAY NIGHT...THEN REFORMING ALONG FRONT OVER MS
RIVER VALLEY MONDAY NIGHT. STG UPPER LEVEL DIVERGENCE LOOKS LIKE
ALMOST A SURE BET AS WELL. SEVERE STORMS ALSO POSSIBLE WITH DISCRETE
CELL DEVELOPMENT LATE SUNDAY. TO TOP IT OFF...BRIEF BUT INTENSE
SHOT OF COLD AIR ON BACKSIDE COULD BE MORE THAN COLD ENOUGH FOR
SLEET EVENT...MIXED WITH SNOW NORTH OF I-20. WILL LEAD INTO THIS
TIMIDLY...AS THERE ARE STILL CLOSE TO 60 HOURS TO WORK WITH ON
THIS EVOLVING DEVELOPMENT./VII/

[Ed Mahmoud]

Looking at raw 12Z GFS numbers, a dusting of snow is possible late Monday afternoon, and then temps will be cold enough aloft, and thicknesses low enough, and temps right on the edge at the surface (near 40ºF) for snow Thursday night/Friday morning.

[Extremeweatherguy]

Check out the 18z GFS run for the system late next week! Things look VERY interesting here in SE Texas...

http://www.nco.ncep.noaa.gov/pmb/nwprod ... p_132l.gif
http://www.nco.ncep.noaa.gov/pmb/nwprod ... p_138l.gif
http://www.nco.ncep.noaa.gov/pmb/nwprod ... p_144l.gif
http://www.nco.ncep.noaa.gov/pmb/nwprod ... p_150l.gif

http://www.nco.ncep.noaa.gov/pmb/nwprod ... p_132l.gif
http://www.nco.ncep.noaa.gov/pmb/nwprod ... p_138l.gif
http://www.nco.ncep.noaa.gov/pmb/nwprod ... p_144l.gif
http://www.nco.ncep.noaa.gov/pmb/nwprod ... p_150l.gif

...The precipitation would still be around even after the cold air in the upper levels moved in. This would mean that a changeover to/a mixing with snow or sleet would be possible. We will have to watch this closely to see what happens!

[Ed Mahmoud]

Check out the 18z GFS run for the system late next week! Things look VERY interesting here in SE Texas...

http://www.nco.ncep.noaa.gov/pmb/nwprod ... p_132l.gif
http://www.nco.ncep.noaa.gov/pmb/nwprod ... p_138l.gif
http://www.nco.ncep.noaa.gov/pmb/nwprod ... p_144l.gif
http://www.nco.ncep.noaa.gov/pmb/nwprod ... p_150l.gif

http://www.nco.ncep.noaa.gov/pmb/nwprod ... p_132l.gif
http://www.nco.ncep.noaa.gov/pmb/nwprod ... p_138l.gif
http://www.nco.ncep.noaa.gov/pmb/nwprod ... p_144l.gif
http://www.nco.ncep.noaa.gov/pmb/nwprod ... p_150l.gif

...The precipitation would still be around even after the cold air in the upper levels moved in. This would mean that a changeover to/a mixing with snow or sleet would be possible. We will have to watch this closely to see what happens!

AccuWx hates me. 18Z GFS PPV numbers show sub-freezing 850 mb temps, but 7ºC (mid 40sF) 2 meter temps. Now, if GFS is correct otherwise, normal bias is too warm on low level temps, so I'm still not giving up hope on a slightly late birthday present.

Mrs. Mahmoud, who isn't into weather (but loves "Lost", so I have encouraged her to register, but she is resisting) has a B-day on March 15th, so this would split the difference.


I started a thread about this system being a 1993 March redux storm, maybe even an 1888 redux storm up North, but there is an element of -removed- to that.

[Extremeweatherguy]

Check out the 18z GFS run for the system late next week! Things look VERY interesting here in SE Texas...

http://www.nco.ncep.noaa.gov/pmb/nwprod ... p_132l.gif
http://www.nco.ncep.noaa.gov/pmb/nwprod ... p_138l.gif
http://www.nco.ncep.noaa.gov/pmb/nwprod ... p_144l.gif
http://www.nco.ncep.noaa.gov/pmb/nwprod ... p_150l.gif

http://www.nco.ncep.noaa.gov/pmb/nwprod ... p_132l.gif
http://www.nco.ncep.noaa.gov/pmb/nwprod ... p_138l.gif
http://www.nco.ncep.noaa.gov/pmb/nwprod ... p_144l.gif
http://www.nco.ncep.noaa.gov/pmb/nwprod ... p_150l.gif

...The precipitation would still be around even after the cold air in the upper levels moved in. This would mean that a changeover to/a mixing with snow or sleet would be possible. We will have to watch this closely to see what happens!

AccuWx hates me. 18Z GFS PPV numbers show sub-freezing 850 mb temps, but 7ºC (mid 40sF) 2 meter temps. Now, if GFS is correct otherwise, normal bias is too warm on low level temps, so I'm still not giving up hope on a slightly late birthday present.

Mrs. Mahmoud, who isn't into weather (but loves "Lost", so I have encouraged her to register, but she is resisting) has a B-day on March 15th, so this would split the difference.


I started a thread about this system being a 1993 March redux storm, maybe even an 1888 redux storm up North, but there is an element of -removed- to that.

The 7˚C (44-45˚F) 2m temperatures are during Friday afternoon. During the early morning though, the temperatures are a little colder (near 40-41˚F at IAH), which would be a good range for us to see sleet or a rain/sleet mix. One other thing that is important to note would be that the GFS is not always the best with evaporative cooling scenarios. If it is actually raining or sleeting, then temperatures would likely be slightly cooler than what is currently being shown by the model. We will just have to wait and see..

[Extremeweatherguy]

The 00z GFS continues to look very, very interesting here in SE Texas next Friday. It shows surface temperatures starting near 38F at IAH in the morning and then rising only into the lower 40s for an afternoon high. (Brr!) During this time, the model is also showing showers in the area with quickly falling 850mb temperatures and thicknesses. Right as the precipitation is starting to end is when things get a bit fun. 850mb temperatures at IAH fall to around 0C, thicknesses fall to near 540 and surface temperatures are in the range of 38-42F. This is a great setup for some sleet or snow to mix in as the showers begin to slowly wind down by late morning and into the early part of the afternoon.

This run then also goes on to show a widespread freeze on Saturday morning. It shows IAH reaching 31F by sunrise Saturday AM, which means that outlying areas could easily reach the 20s.