Texas winter wx thread (2009-2010)

[Tejas89]

•1978 - The largest 24-hour snowfall ever (12.1") began on the following day.

The first snowstorm I have any memory of, and I guess the biggest to this day. We lived in McKinney.

As for this event it seems like temps will be an issue as always for DFW. Most of the local mets have us above or just at freezing throughout the time period. Need these models to cool us off 4-5 deg's. before I get my sled shined up.

[srainhoutx]

EXTENDED FORECAST DISCUSSION
NWS HYDROMETEOROLOGICAL PREDICTION CENTER CAMP SPRINGS MD
115 PM EST MON FEB 08 2010

VALID 12Z THU FEB 11 2010 - 12Z MON FEB 15 2010

...SOUTHERN SNOW POSSIBLE THURSDAY THROUGH SATURDAY...

TELECONNECTIONS WITH A STRONG POSITIVE ANOMALY IN THE MID-LEVELS
OVER NORTHEAST CANADA /BETWEEN 3 AND 4 STANDARD DEVIATIONS ABOVE
NORMAL/ FAVORS PROGRESSIVE CLOSED CYCLONES UNDER ITS BASE IN THE
LOWER 40S LATITUDE. THIS ALLOWS US TO DISCARD THE 00Z CANADIAN
WHICH LEAVES A CLOSED CYCLONE QUASI-STATIONARY IN THE NORTHERN
PLAINS/UPPER MIDWEST LATE IN THE PERIOD. SHORTWAVE ENERGY IN THE
SOUTHERN STREAM IS EXPECTED TO REMAIN PROGRESSIVE ACROSS THE
SOUTHERN TIER OF THE COUNTRY THROUGH THE FORESEEABLE FUTURE. DUE
TO THE PROGRESSION EXPECTED IN THE NORTHERN AND SOUTHERN STREAMS
AS WELL AS QUESTIONS REGARDING FUTURE INTERACTIONS BETWEEN THE TWO
STREAMS... CONFIDENCE IN THE FORECAST LATE THIS WEEKEND INTO EARLY
NEXT WEEK IS LOW IN ANY PARTICULAR PIECE OF DETERMINISTIC
GUIDANCE...WHICH IS LIKELY TO SHOW RUN-TO-RUN AND DAY-TO-DAY
DIFFERENCES REGARDING PROGRESSION AND PHASING. BOTH THE 06Z GEFS
MEAN AND 00Z ECMWF ENSEMBLE MEANS ARE IN REASONABLE AGREEMENT
THROUGH THE PERIOD. IN ORDER TO RESOLVE DETAIL ISSUES...CHOSE TO
COMPROMISE BETWEEN THE 00Z ECMWF AND 06Z GEFS MEAN
SOLUTIONS...WITH SOME MODIFICATIONS MADE PER 00Z MULTI-MODEL
ENSEMBLE LOW PRESSURE AREA CLUSTERING...SUCH AS THIS WEEKEND NEAR
FLORIDA AND LATE IN THE PERIOD IN THE GULF OF MEXICO.

DEEP CYCLONE MOVING BY THE PACIFIC NORTHWEST SATURDAY/SUNDAY...
A COMPROMISE OF THE 06Z GEFS MEAN/00Z ECMWF KEPT THIS SYSTEM
WITHIN THE MIDDLE OF THE ENSEMBLE SPREAD POSITION-WISE. HEAVY
PRECIPITATION IS EXPECTED WITH THE SYSTEM FROM WASHINGTON
STATE/THE OLYMPIC PENINSULA NORTHWARD TO VANCOUVER ISLAND. AT
THIS TIME...THE CASCADES ARE EXPECTED TO HAVE LESSER AMOUNTS...BUT
ONLY A SLIGHT SHIFT TO THE SOUTH WOULD BRING MUCH HEAVIER
PRECIPITATION INTO THE MOUNTAIN RANGE.

GREAT LAKES...
AS A STRONG AND DEEP CYCLONE MOVES OFFSHORE THE NORTHEAST AND
RETROGRADES INTO ATLANTIC CANADA...COLD AIR WITHIN THE CYCLONIC
FLOW ON ITS BACK/SOUTHWEST SIDE SETS THE STAGE FOR LAKE EFFECT
SNOWS THROUGH THE PERIOD.

SOUTHERN STREAM SYSTEM MOVING THROUGH FLORIDA FRIDAY...
THE ECMWF SHOWS A TWO DAY TREND TOWARDS SLOWING THIS SYSTEM
DOWN...AND ITS 00Z SOLUTION LIES WITHIN THE SOUTHERN PORTION OF
THE ENSEMBLE ENVELOPE. TO ACCOUNT FOR THE TREND...TOOK THE LOW ON
A SLOWER/MORE NORTHERLY PATH...WITHIN THE NORTHWEST SIDE OF THE
00Z MULTI-MODEL ENSEMBLE LOW ENVELOPE. THIS SYSTEM IS EXPECTED TO
BE QUITE WET ALONG THE GULF COAST AND FLORIDA...WITH STRONG
THUNDERSTORMS POSSIBLE ACROSS THE FLORIDA PENINSULA TO THE SOUTH
OF ITS TRACK AS THE LOW PASSES THROUGH. MEASURABLE SNOW IS
POSSIBLE WITHIN ITS NORTHERN PERIPHERY FROM TEXAS EASTWARD ACROSS
THE DEEP SOUTH INTO SOUTH CAROLINA FROM THURSDAY INTO SATURDAY AS
1000-500 HPA THICKNESS VALUES WITH THE PREFERRED MODEL BLEND ARE
ANTICIPATED TO BE BELOW 5400 METERS.
ROTH

[txagwxman]

ECMWF 540 thickness down to IAH now on Friday morning.

[katheria]

:uarrow: Can't take that too closely, it only gives a general idea of where the potential is. No way to know for sure locally how much where and when until the event happens Katheria.

yep i know.... but i can dream

my luck it will be all rain here LOL

[southerngale]

I sure wish we could get in on the action down here. All of the snow threats are further north, which I realize is logical, but we still feel left out! It's been a very cold winter... snow makes it all worthwhile. So send that snow line down south... pretty please, with sugar on top.

Congrats to all you Saints fans. I was pulling for them too.

[wxman57]

ECMWF 540 thickness down to IAH now on Friday morning.

True, but precip is long-gone by then. I think our (Harris County - Houston) best shot at anything frozen comes early in the precip onset.

[DentonGal]

Graphic from the FW NWS of Wednesday night through Friday morning...

http://www.srh.noaa.gov/images/fxc/fwd/ ... _full4.gif

[Weatherdude20]

Graphic from the FW NWS of Wednesday night through Friday morning...

http://www.srh.noaa.gov/images/fxc/fwd/ ... _full4.gif

LOL

[Portastorm]

Graphic from the FW NWS of Wednesday night through Friday morning...

http://www.srh.noaa.gov/images/fxc/fwd/ ... _full4.gif

LOL

Oh my ... if this storm even comes close to what the 12z GFS is showing, that graphic and forecast is going to look pretty ridiculous!

[wxman57]

The latest forecast for Dallas has me perplexed:

THURSDAY...CLOUDY. A CHANCE OF RAIN AND SNOW IN THE MORNING...
THEN RAIN AND SNOW LIKELY IN THE AFTERNOON. HIGHS IN THE UPPER
30S. CHANCE OF PRECIPITATION 60 PERCENT

THURSDAY NIGHT...MOSTLY CLOUDY WITH A 50 PERCENT CHANCE OF RAIN
AND SNOW. LOWS IN THE LOWER 30S.

I've looked at all available guidance, and all guidance has the Metroplex below freezing at all levels on Thursday. That's a snow profile not a "rain and snow" profile.

And from their latest AFD:
AS FOR THE THURSDAY SYSTEM...NAM/ECMWF ARE MORE CONSERVATIVE WITH
QPF BUT IT DOES LOOK LIKE WE WILL SEE A WINTER MIX. AFTERNOON
TEMPERATURES WILL BE ABOVE FREEZING ACROSS ALL OF NORTH TEXAS...SO
EVEN THOUGH WE HAVE ALMOST A HALF INCH OF SNOW FALL POSSIBLE IN
THE NORTHEAST...IT WILL MELT RATHER THAN ACCUMULATE. ISOLATED
TRAVEL PROBLEMS MAY OCCUR THURSDAY MORNING WHEN FREEZING
TEMPERATURES ARE EXPECTED NORTH OF A LINE FROM LAMPASAS TO
CANTON...AND AGAIN AFTER MIDNIGHT THURSDAY NIGHT THROUGH SUNRISE
FRIDAY.

I'm not so sure that's true either (temps above normal all areas Thursday afternoon). Model guidance doesn't agree, and the GFS has trended a bit too warm with previous systems. Here's the 12Z GFS meteogram for DFW. 0.9" of liquid precip with temps surface and aloft sub-freezing. NAM is a tad warmer and with a bit less precip.

[katheria]

Graphic from the FW NWS of Wednesday night through Friday morning...

http://www.srh.noaa.gov/images/fxc/fwd/ ... _full4.gif

LOL

Oh my ... if this storm even comes close to what the 12z GFS is showing, that graphic and forecast is going to look pretty ridiculous!

fws nws has always been humm whats the word shy about making winter predictions...
im not sure when it was but many years ago, they forecast ice/snow ect and all the cities put all their road crews on full alert and overtime shifts...nothing happened...it cost dallas quite a bit of money...I remember there was alot of not so nice talk... maybe this is why they are shy about saying more...

[srainhoutx]

ECMWF 540 thickness down to IAH now on Friday morning.

Do you see any QPF remaining? Also is the H5 low a tad further S and lagging back just a bit?

[DentonGal]

This is a purely selfish question. I have to take my daughter to Medical City in Dallas on Thursday morning to meet with a Pediatric Cardiac Electrophysiologist. Living in Denton, am I going to have problems making an 8:30 a.m. appointment? His next available opening isn't until April, which is a long time to wait. Do you see freezing temps and moisture being there early Thursday morning, or do you think this will be an afternoon event?

[wxman57]

This is a purely selfish question. I have to take my daughter to Medical City in Dallas on Thursday morning to meet with a Pediatric Cardiac Electrophysiologist. Living in Denton, am I going to have problems making an 8:30 a.m. appointment? His next available opening isn't until April, which is a long time to wait. Do you see freezing temps and moisture being there early Thursday morning, or do you think this will be an afternoon event?

I'd say that you could have significant problems on that drive. It's not a 100% guarantee, yet, but probably over 50%. If it were me, I'd reschedule the appointment for next Monday if the appointment could be delayed without endangering your daughter.

[Tejas89]

This is a purely selfish question. I have to take my daughter to Medical City in Dallas on Thursday morning to meet with a Pediatric Cardiac Electrophysiologist. Living in Denton, am I going to have problems making an 8:30 a.m. appointment? His next available opening isn't until April, which is a long time to wait. Do you see freezing temps and moisture being there early Thursday morning, or do you think this will be an afternoon event?

There are plenty of hotels along that stretch and I doubt Dallas proper will be ice-locked Thursday a.m. Not sure how urgent the appt. is, but just my $.02. The drive from Denton to Dallas would worry me more since Denton seems to get hit harder and earlier most of the time due to lower temps up there.

edit: of course you may want to reserve that room for a day or two given you have to drive home too!!

[Ntxw]

Thanks wxman, your meteogram in this case would do wonders for those of us planning things around this time frame. And this storm seems to be the further south/east you go (metro area)the worst the conditions could be. Should there be a cutoff area it might not seem so bad in Denton at the time but down in Dallas could be a whole other animal, just my speculation. I think wxman said it best, if it's not necessary and there are options, would consider re-scheduling if possible. It doesn't take a lot of snow or ice to cause havoc in Dallas proper. The fanfare of it all is enough to cause traffic issues.

[TeamPlayersBlue]

Im driving from Nacogdoches to Dallas on Thurs afternoon. Going there for All-Star weekend. Could be a very interesting drive from the looks of things

[DentonGal]

This is a purely selfish question. I have to take my daughter to Medical City in Dallas on Thursday morning to meet with a Pediatric Cardiac Electrophysiologist. Living in Denton, am I going to have problems making an 8:30 a.m. appointment? His next available opening isn't until April, which is a long time to wait. Do you see freezing temps and moisture being there early Thursday morning, or do you think this will be an afternoon event?

I'd say that you could have significant problems on that drive. It's not a 100% guarantee, yet, but probably over 50%. If it were me, I'd reschedule the appointment for next Monday if the appointment could be delayed without endangering your daughter.

Thanks Wxman57. The specialist travels in from Houston once a month, so I'm not sure he would even make it to Medical City in Dallas if roads and airports are closed. I will contact her regular cardiologist Wednesday morning if there is a more definite probability of hazardous driving conditions for Thursday and see what he suggests. I was really hoping for a Thursday afternoon event. Thanks again.

[DentonGal]

This is a purely selfish question. I have to take my daughter to Medical City in Dallas on Thursday morning to meet with a Pediatric Cardiac Electrophysiologist. Living in Denton, am I going to have problems making an 8:30 a.m. appointment? His next available opening isn't until April, which is a long time to wait. Do you see freezing temps and moisture being there early Thursday morning, or do you think this will be an afternoon event?

There are plenty of hotels along that stretch and I doubt Dallas proper will be ice-locked Thursday a.m. Not sure how urgent the appt. is, but just my $.02. The drive from Denton to Dallas would worry me more since Denton seems to get hit harder and earlier most of the time due to lower temps up there.

edit: of course you may want to reserve that room for a day or two given you have to drive home too!!

Thanks Tejas89 - my husband and I have been discussing that option as well. The only time I can ever remember NOT wanting snow and/or ice....

[srainhoutx]

I haven't seen this discussed yet, but doesn't the 0z European (days 9-10), show a deep trough over the central CONUS and Texas? What are the implications if this verifies?

12Z ECMWF says the pattern continues...