How cold could it get? (Texas)

[cctxhurricanewatcher]

Some models and some NWS offices here in Texas are saying the cold will hit us, but the brut will be off to the east. Some on this board and Bastardi to some extent are suggesting a direct hit with the Siberran Express. If that is the case, will we see 1983 or 1989 stuff down this way.

I do notice the NWS AFD's this AM look very, very unsure about the pattern for this weekend in most cases. That's better than what was put out by some a couple of days ago that wrote it off based on one or two model runs on one particular model.

[gboudx]

The DFW NWS was off on both temps and precip for the arctic front that passed through before Xmas. Temps wound up being 5-10 degrees colder than they forecasted, and precip was more prolonged, widespread and intense than forecasted. Also, I think the front came through faster than they expected. This isn't meant as a knock against those guys, because I think they do a good job. More, it appears it's tough to make a forecast days in advance when very cold air is involved.

[QCWx]

I seriously doubt it will be of 1983 or 1989 proportions so you can throw that out right now. It'll probably just be one really cold day and thats it.

[Portastorm]

The last few GFS runs seem to shunt the coldest air northeast of Texas. Last night's Euro run did not and brought the "motherlode" due south in to the Lone Star State.

If the former verifies, I would venture a guess that we see Christmas 2004-like temps for a few dats. If the latter verifies, something much more colder would be in the offing.

[Kelarie]

Does it look like any precip will be falling during this time? I am looking at the Central Texas area.

Thanks,
Kel

[aggiecutter]

I think this has the potential to be a record breaking air-mass for the southern plains and Texas. The GFS has been flipping back and forth every-other run as to where the core of the cold will go. One run will put the core in the midwest. The next run it has the core heading straight down into Texas.

Past history will tell you that dense cold, shallow air masses of Siberian orgin act a lot like throwing mollasses on a sphere. Because of the density of the air mass and the natural curvature of the earth, they seem to ooze southward with time and spread out, rather than being shuntted off to the east. I think today's 6z run of the GFS has good idea of what will happen this weekend.

6z GFS...
http://www.nco.ncep.noaa.gov/pmb/nwprod ... _168.shtml

[Portastorm]

Does it look like any precip will be falling during this time? I am looking at the Central Texas area.

Thanks,
Kel

Kel,

Right now it doesn't look like a decent shot of precip will occur this weekend. Looks fairly dry. However there is some hint that maybe Mon-Tues of next week a system would present a threat ... question is how cold will the atmosphere be at that time?!

[Kelarie]

Portasotorm,

The only reason I ask, is I could really use an extra long week in front of the fireplace.

[Portastorm]

Several TX NWS offices sounding the alarm about the cold this weekend and a possible winter precip event late in the weekend and next Monday. Granted this is WAY EARLY to speculate but I really thought that the forecast discussion out of New Braunfels this afternoon was well done. They lay out the facts, give a "heads up" about a possible event and use all the tools at their disposal.

Let me be the first to say "NWS, good work!!"

[Johnny]

Portastorm, can you post that discussion over here when you get a minute? Thanks.

[jeff]

Intense Arctic Outbreak building in N Canada.

Major pattern shift will deliver extremely cold to record breaking
cold air into the US by the end of this week.

Current through Wednesday PM:

Upper level ridging continues to pump low level moisture into the
region this afternoon. Dewpoints have recovered from the low 30's this
weekend to the mid and upper 60's. Sea fog continues to hang tough
along the coast as dewpoints exceed sea surface temps. Streamer
showers will be developing under the capping inversion through midday
Wed. Strong short wave and Pacific cool front blast through on
Wednesday evening. Moisture and dynamics may provide a shot at a
squall line with a severe wind threat, however capping may be hard to
overcome.

Thurs-Sun:

Frigid arctic air pours southward out of Canada behind the Wed storm
system. Models bring the arctic front into N TX late Thursday and
through SE TX sometime Friday. 850mb temps are progged as low as -8C
to -12C into N TX and W TX by Saturday AM. GFS is way too warm with
this air mass and I will undercut its numbers by 20 degrees for highs
for KIAH. There is the possibility that the most brutal chunk of cold
air moves moves E of TX, however given the pattern setup and density
of this air mass, I believe a good strong shot will be delivered into
TX. Will go with freezing temps. Friday evening with highs struggling
in the 30's on Saturday. Hard freeze is possible Saturday night if we
stay clear.

Sunday:

Disturbance in the polar flow may induce upgliding over the very cold
surface air mass. Will go with increasing clouds for now and delay any
mention of precip. Forecast soundings show a cold layer being
maintained, so this is something to keep a close eye on as we could
have to deal with some freezing or frozen precip. Plenty of time to
watch this however.

Note: Record highs may be set today through Wed. over the region as
temps. for lows remain in the 60's and highs push the lower 80's. The
bottom will fall out on this come Friday however, be prepared.

Jeff L

[Portastorm]

Portastorm, can you post that discussion over here when you get a minute? Thanks.

You bet Johnny .... read below:

From Austin/San Antonio NWS:
ECMWF/GLS DIFFER ON TIMING OF INITIAL COLD AIR AND
SUBSEQUENT SURGES OVER THE WEEKEND...WITH THE ECMWF A LITTLER
SLOWER/WEAKER WITH THE INITIAL SURGE...BUT SHOWING A STRONGER SECOND
SURGE LATE SATURDAY/SUNDAY. EITHER WAY A COLD WEEKEND IN STORE FOR S
TX AND WILL LEAVE ONGOING MUCH BELOW NORMAL TEMPS ALONE FOR NOW.
THERE ARE SOME INDICATIONS FOR MOISTURE TRYING TO RETURN OVER THE
TOP OF THE COLD SFC RDG LATE IN THE WEEKEND INTO EARLY NEXT
WEEK...MAKING A CASE FOR SOME SORT OF FRZG/FRZN PCPN. HOWEVER MSTR
APPEARS OVERDONE AS THE PRESENCE OF A S/W RDG JUST TO THE WEST
SHOULD KEEP LOW AND MID LEVEL MOISTURE OUT OF THE AREA. WILL LEAVE
FORECAST DRY FOR NOW AND CONTINUE TO WATCH FUTURE MODEL RUNS FOR
ANY PSBL WINTER WX.

From Corpus Christi NWS:
INTENSE POLAR AIRMASS PROGGED TO FOLLOW THE FRONT...BRINGING
BITTERLY COLD AIR TO THE UPPER MIDWEST AND WESTERN LAKES REGION.
SOME OF THAT VERY COLD...VERY DENSE AIR IS LIKELY TO PUSH DOWN TO
OUR REGION. CURRENT FORECAST TEMPS FOR FRI/SAT/SUN ARE 10 OR MORE
DEGREES BELOW GUIDANCE...AND ABSOLUTELY WARRANTED. ISENTROPIC LIFT
LATE SUNDAY INTO MONDAY MAY RESULT IN SOME NUISANCE
PRECIPITATION...BUT NOT ENOUGH TO WARRANT ZONE MENTION ATM.


From San Angelo NWS:
MEANWHILE THE COLDER
AIRMASS WILL BEGIN TO INVADE ON FROM THE BACKDOOR OR THE NORTHEAST.
WITH SEVERAL PROGRESSIVLY COLDER AIRMASSES COMING DURING THE
WEEKEND. WITH THE CLIMAX IN THE COLD AIR EXPECTED ON SUNDAY OR
MONDAY. WE ARE STILL WELL BELOW GUIDANCE NUMBERS AND IN SOME
INSTANCES WE ARE BELOW THE ENSEMBLE SPREAD...AND THIS SEEMS
REASONABLE WITH THE AMOUNT OF COLD AIR EXPECTED LATE IN THE
PERIOD. MOS GUIDANCE LIKELY TRENDING TOO MUCH TOWARDS CLIMO.
ALTHOUGH WE ARE WELL BELOW GUIDANCE...STILL THINK WE MAY BE TOO
WARM...ESPECIALLY SUNDAY AND MONDAY. ALSO WE ARE WATCHING AN
OVERRUNNING SITUATION DEVELOPING ON MONDAY THAT COULD PRODUCE SOME
WINTRY PRECIPITATION...BUT WILL CONTINUE TO MONITOR THIS IN LATER
FORECASTS. WILL LIKELY ISSUE AN SPECIAL WEATHER STATEMENT THIS
AFTERNOON TO HIGHLIGHT THE UPCOMING COLD AIR EVENT.

[cctxhurricanewatcher]

Portastorm

You're right, hat's off to the NWS offices in Texas this afternoon. All of the AFD's are in line for the most part for once. Makes you wonder if some of the old school forecasters saw the models and got on the phones with their successors.

Of course everything will probably be back to chaos once the AM shift comes back on.

[Johnny]

Portastorm...thanks for posting the discussions. Much appreciated.

Jeff...very good writeup. You are forecasting a chilly forecast which seems pretty reasonable. Keep up the good work!

[Burn1]

Real cold stuff should stay just to the east of Texas and north of the
Gulf Coast and Florida.....Just a tad below normal for Texas, Gulf Coast and Florida. However it should be nice as it will stay around for a while.

[krysof]

when willl central new jersey see some cold or snow? I'm sick of this mild weather and I heard it could be in the mid 60's on Thursday, what next 70's by Friday.

[WhiteShirt]

Intense Arctic Outbreak building in N Canada.

Major pattern shift will deliver extremely cold to record breaking
cold air into the US by the end of this week.

Current through Wednesday PM:

Upper level ridging continues to pump low level moisture into the
region this afternoon. Dewpoints have recovered from the low 30's this
weekend to the mid and upper 60's. Sea fog continues to hang tough
along the coast as dewpoints exceed sea surface temps. Streamer
showers will be developing under the capping inversion through midday
Wed. Strong short wave and Pacific cool front blast through on
Wednesday evening. Moisture and dynamics may provide a shot at a
squall line with a severe wind threat, however capping may be hard to
overcome.

Thurs-Sun:

Frigid arctic air pours southward out of Canada behind the Wed storm
system. Models bring the arctic front into N TX late Thursday and
through SE TX sometime Friday. 850mb temps are progged as low as -8C
to -12C into N TX and W TX by Saturday AM. GFS is way too warm with
this air mass and I will undercut its numbers by 20 degrees for highs
for KIAH. There is the possibility that the most brutal chunk of cold
air moves moves E of TX, however given the pattern setup and density
of this air mass, I believe a good strong shot will be delivered into
TX. Will go with freezing temps. Friday evening with highs struggling
in the 30's on Saturday. Hard freeze is possible Saturday night if we
stay clear.

Sunday:

Disturbance in the polar flow may induce upgliding over the very cold
surface air mass. Will go with increasing clouds for now and delay any
mention of precip. Forecast soundings show a cold layer being
maintained, so this is something to keep a close eye on as we could
have to deal with some freezing or frozen precip. Plenty of time to
watch this however.

Note: Record highs may be set today through Wed. over the region as
temps. for lows remain in the 60's and highs push the lower 80's. The
bottom will fall out on this come Friday however, be prepared.

Jeff L

Jeff,
What kind of highs can we expect in the Houston/SE Texas area when this front comes in?

[aggiecutter]

12z EURO has what will be close to record breaking high pressure ridging from the central plains down into Texas. I think a lot of people are going to be surprised how cold this air is going to be.

Checkout day 6 and 7 MSLP at Stormfury's site.

http://www.stormsfury1.com/Weather/Models/ECMWF.html

[Air Force Met]

Real cold stuff should stay just to the east of Texas and north of the
Gulf Coast and Florida.....Just a tad below normal for Texas, Gulf Coast and Florida. However it should be nice as it will stay around for a while.

Sorry...real cold stuff is coming south. A tad below normal for us would be lows in the mid-30's and highs in the mid 50's. I'll bet the double wide that ain't happening.

Remember...models do not handle artic air well. They want to move it too slow and try to take the brunt east. Anytime you have a 1050+mb high in the northern plains and Montana...as forecast...that sucker is coming due south along the lee side of the rockies. Bank on it.

[Air Force Met]

If that is the case, will we see 1983 or 1989 stuff down this way.

Models are particularily bad when it comes to forecasting artic air. They always want to move it east...because the upper-air flow normally directs a polar high along the 500 mb flow. The problem with the local NWS office (and I suspect some other ones) is they are relying too much on the model temps. The GFS has been horrible on the temps...and artic air is not going to to get shoved east...it is coming south. Also...the GFS tries to hold the artic air up in Canada. It moves a 1050 mb high slowly SE. That also is not going to happen.

I don't think we will see temps on the order of 83 or 89...mainly because some of the artic air got tapped last week...but I suspect we will see upper teens in SE Texas and a day or two that does not get above (or mayeb only a few degrees above) freezing . But...this is really hard to forecast because you are really doing it blind without model support.