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


Portastorm

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Looks like the 18z GFS continues the trend of each model run coming in a tad cooler and  the 18z 4k WRF/NAM expanded the freezing rain area to the south again.  Also, the 12z Euro EPS seemed to support the operational idea of much of DFW getting some form of frozen precipitation.  Temp has been slowly falling IMBY but officially still 34 at KTKI. 

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Looks like the 18z GFS continues the trend of each model run coming in a tad cooler and  the 18z 4k WRF/NAM expanded the freezing rain area to the south again.  Also, the 12z Euro EPS seemed to support the operational idea of much of DFW getting some form of frozen precipitation.  Temp has been slowly falling IMBY but officially still 34 at KTKI. 

 

Already 33°F at DFW Airport. Dan Henry is almost always too warm on temps. He is usually 2 to 5 degrees warmer than the NWS. He must be basing his forecast strictly in the heart of downtown Dallas. Steve McCauley has a good writeup about the event on his Facebook page and is calling for some ice in the Metroplex, especially the further west one goes.

 

BTW Bubba OT - Do you have a weather station at your house? If so, what kind and how do you like it?

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Dan Henry not buying the hype and keeps Dallas above freezing? From his Twitter:

 

B6OG5ylCUAEs4kX.png

 

ETA: It looks like that doesn't account for the low tonight?

Which frankly that contradicts what he said on the news at 5 and 5:30, calling for some ice for just about everyone, more West of 35W..

 

FYI Alliance is already below freezing (no real surprise there, Alliance seems to always be the ice box of the metroplex

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Looks like DFW will be mostly spared, with significant icing staying out to the NW and that is totally fine by me.

 

B6QznfjIIAADQY2.png

MESOSCALE DISCUSSION 0002
NWS STORM PREDICTION CENTER NORMAN OK
0555 AM CST THU JAN 01 2015

AREAS AFFECTED...NRN TX INTO SERN OK AND WRN AR

CONCERNING...FREEZING RAIN

VALID 011155Z - 011800Z

SUMMARY...SPORADIC SHOWERS OF FREEZING RAIN WILL PERSIST THIS
MORNING FROM NRN TX INTO WRN AR...WITH LIGHT ACCUMULATIONS POSSIBLE.

DISCUSSION...MOISTENING AND LIFT ASSOCIATED WITH AN APPROACHING
UPPER TROUGH WILL ALLOW EXISTING SHOWERS TO EVOLVE NEWD OUT OF TX
AND INTO SERN OK AND WRN AR. HRLY QPF RATES UP TO 0.04 INCHES HAVE
BEEN OBSERVED NEAR DALLAS BUT THE FREEZING RAIN ZONE WILL REMAIN
MAINLY TO THE NW.

ALTHOUGH SOME LOW-LEVEL WARMING/MIXING MAY OCCUR...EVAPORATIVE
COOLING WILL ALSO OCCUR WITH THE NET RESULT A NEARLY STATIONARY
SURFACE FREEZING LINE. AS SUCH...THE BEST THREAT FOR LIGHT ICING
WILL BE ALONG A MWL TO DTO TO FSM LINE THROUGH MIDDAY.
THEREAFTER...MUCH OF THE PRECIPITATION SHOULD BE IN THE FORM OF
RAIN.

..JEWELL.. 01/01/2015

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that would be 1989 redux looking at that model output... certainly something to keep our eyes on for sure 

 

Not quite, if you are referring to February 1989. It was much colder in North Texas with a 1060 mb high pressing down the spine of the Rockies with temperatures running in the single digits and teens across North Texas. That graphic is only showing temps in the upper 20s.

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SJT extends Winter Storm Warning for Brown, Callahan, Coke, Coleman, Concho, Crockett, Fisher, Haskell, Irion, Jones, Kimble, Mason, McCulloch, Menard, Nolan, Runnels, San Saba, Schleicher, Shackelford, Sterling, Sutton, Taylor, Throckmorton, Tom Green Counties until 3:00PM CST.

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Looks like a few inches of snow for the Panhandle and northern West Texas tomorrow with the upper low passing overhead. Showers will continue across much of the rest of the day tomorrow before a line of storms develops tomorrow night across North and Central Texas and heads east exiting the state by midday Saturday. Cool temps will continue into next week, but tomorrow's West Texas snow should be the last of the wintery stuff for a bit. With the fresh snowpack and better upper air pattern next week may see colder temps than this week for eastern Texas even though the high will not be near as strong.

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Next weekend? I see ice & snow for OK, but nothing really interesting for DFW area. Can you post what you're saying? 

 

It's just purely speculation, there is some energy kicking out of the SW and some northern stream energy coming down with cold air in place.  You can do the mental gymnastics and play around with timing, strength, and track to get a couple of long shot scenarios. 

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It's just purely speculation, there is some energy kicking out of the SW and some northern stream energy coming down with cold air in place.  You can do the mental gymnastics and play around with timing, strength, and track to get a couple of long shot scenarios. 

Well I see what you mean. That's really a long shot... i guess i miss Dec 6 2013 event too much :cry:

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Interesting discussion out of the FWD NWS AFD this morning. Talking about the 0z ECMWF operation model showing near record surface pressures near 1050mb or 31.00 inHg for North Texas with second very cold Arctic shot later this week. If true, surface temperatures will be well down in the teens with some single digits around the area.

 

THE LATEST ECMWF MOS FOR THURSDAY MORNING HAS LOWS NEAR 10 DEGREES NORTH AND WEST OF THE METROPLEX. CURRENT FORECAST WONT BE QUITE THAT COLD BUT WE MAY NEED TO TWEAK THESE DOWN IF THE TREND CONTINUES. DESPITE THE COLD...IT LOOKS LIKE IT WILL BE DRY SO WE SHOULDNT HAVE ANY WINTRY WEATHER AROUND THE AREA. ANOTHER LITTLE INTERESTING THING ABOUT THE ECMWF...IS THAT IF THE PRESSURES ARE AS HIGH AS FORECAST...THEY WOULD BE AROUND 1050MB ACROSS PARTS OF TEXAS...WHICH WOULD PUSH BAROMETERS UP TO NEAR 31 INCHES. ITS BEEN QUITE A WHILE SINCE THEY HAVE BEEN THAT HIGH IN NORTH TEXAS.

 

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The 12Z GFS is a bit 'colder' than the 00Z run, but the wild card continues to be the upper air disturbance to our West advancing E with its mid/high level clouds and moisture. It would likely be too dry at the surface for any of that moisture to survive the dry low levels, but we are in the 120 hour range, so it is worth monitoring. Regardless, the 2 meter temperatures are worrisome and suggest a hard freeze could be likely into the Coastal Counties of Matagorda Bay on E into Louisiana.

 

 


 

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It's just purely speculation, there is some energy kicking out of the SW and some northern stream energy coming down with cold air in place.  You can do the mental gymnastics and play around with timing, strength, and track to get a couple of long shot scenarios. 

 

FWD offers their take on this long shot event:

 

THE MAIN CHALLENGE IN THIS FORECAST IS THE TAIL END OF THE EXTENDED

PERIOD. AN UPPER LEVEL LOW WILL WANDER AROUND THE BAJA REGION

DURING THE NEXT FEW DAYS...BUT MODEL GUIDANCE IS IN GOOD AGREEMENT

ON EJECTING THIS OUT INTO OUR REGION BY FRIDAY OR SATURDAY. THIS

LOW IS NOT FORECAST TO BE PARTICULARLY STRONG BUT IT WILL POSSESS

AMPLE MID-UPPER LEVEL PACIFIC MOISTURE. IN ADDITION IT SHOULD

INDUCE SOUTHERLY FLOW IN THE LOW LEVEL BY FRIDAY EVENING...WHICH

MEANS IT WILL TAP INTO SOME GULF MOISTURE AS WELL. THE FORECAST

ISSUE IS THAT WHEN THIS MID-UPPER LEVEL MOISTURE AND LIFT BEGIN TO

ARRIVE...TEMPERATURES THURSDAY NIGHT AND FRIDAY MORNING WILL

PROBABLY BE A FEW DEGREES BELOW FREEZING. HOWEVER THE LOW LEVEL

AIRMASS WILL ALSO BE VERY DRY...SO IT IS POSSIBLE PRECIPITATION

ALOFT WILL EVAPORATE AND NOT REACH THE GROUND UNTIL AFTER TEMPS

WARM ABOVE FREEZING. IF PRECIP WERE INTENSE ENOUGH TO SATURATE THE

LOW LEVELS QUICKLY...SOME TYPE OF FREEZING OR FROZEN PRECIPITATION

WOULD BE THE RESULT FRIDAY MORNING.

THE CANADIAN IS INDICATING A SNOW/SLEET MIXTURE AND A HEALTHY

AMOUNT OF QPF FRIDAY MORNING...BUT I TRUST THIS MODEL THE LEAST IN

THE EXTENDED. THE GFS HAS SIGNIFICANTLY WARMER TEMPS ALOFT WHICH

MAKES SENSE GIVEN THE PACIFIC ORIGIN OF THIS SYSTEM. THE GFS WOULD

SUPPORT A FREEZING RAIN OR SLEET MIX THAT CHANGES TO RAIN DURING

THE DAY FRIDAY. THE ECMWF DID HAVE SOME LIGHT WINTRY PRECIP ON THE

0Z RUN...BUT THE 12Z CAME IN A LITTLE SLOWER WITH THE LOW AND THUS

HAD NO QPF UNTIL LATE FRIDAY WHEN TEMPS ARE MARGINALLY ABOVE

FREEZING. CONFIDENCE IN WINTER PRECIP OCCURRING IS LOW BECAUSE

THERE IS NOT A GOOD FORECAST SIGNAL OCCURRING IN THE SYNOPTIC

PATTERN. IN OTHER WORDS...THE 500MB PATTERN DOES NOT MATCH ONE OF

OUR CLASSIC SIGNIFICANT SNOW OR ICE PRODUCING PATTERNS. LAST WEEK

WE HAD A GOOD FORECAST SIGNAL IN THE SYNOPTIC DATA FOR WINTER

WEATHER POTENTIAL 8 TO 10 DAYS OUT BECAUSE MODELS WERE SHOWING

SIMILARITIES TO A SYNOPTIC PATTERN THAN PRODUCED OVER HALF OF OUR

SIGNIFICANT SNOW SYSTEMS OVER THE LAST 50 YEARS. MODELS DID CHANGE

THE FORECAST PATTERN SLIGHTLY OVER THE COURSE OF SEVERAL DAYS THAT

MADE SNOW UNLIKELY...BUT STILL IT WAS A GOOD HEADS UP THAT WINTER

POTENTIAL WAS INCREASING BECAUSE THERE WAS A STRONG CLIMATOLOGICAL

BASIS. THIS WEEK THE CLIMATOLOGY SIGNAL IS NOT ONE THAT PRODUCES

MAJOR WINTER EVENTS. INSTEAD WE HAVE AN EVENT THAT REQUIRES THE

PACIFIC SYSTEM TO ARRIVE IN A COMPARATIVELY TINY TEMPORAL WINDOW.

BECAUSE WITHOUT ANY MORNING PRECIPITATION...THE COLD AIR WOULD

MODIFY ABOVE FREEZING BY MIDDAY FRIDAY. WILL KEEP THE MENTION OF

POPS AS ALL LIQUID FRIDAY AND CONTINUE TO MONITOR THIS CLOSELY.

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FWD offers their take on this long shot event:

 

THE MAIN CHALLENGE IN THIS FORECAST IS THE TAIL END OF THE EXTENDED

PERIOD. AN UPPER LEVEL LOW WILL WANDER AROUND THE BAJA REGION

DURING THE NEXT FEW DAYS...BUT MODEL GUIDANCE IS IN GOOD AGREEMENT

ON EJECTING THIS OUT INTO OUR REGION BY FRIDAY OR SATURDAY. THIS

LOW IS NOT FORECAST TO BE PARTICULARLY STRONG BUT IT WILL POSSESS

AMPLE MID-UPPER LEVEL PACIFIC MOISTURE. IN ADDITION IT SHOULD

INDUCE SOUTHERLY FLOW IN THE LOW LEVEL BY FRIDAY EVENING...WHICH

MEANS IT WILL TAP INTO SOME GULF MOISTURE AS WELL. THE FORECAST

ISSUE IS THAT WHEN THIS MID-UPPER LEVEL MOISTURE AND LIFT BEGIN TO

ARRIVE...TEMPERATURES THURSDAY NIGHT AND FRIDAY MORNING WILL

PROBABLY BE A FEW DEGREES BELOW FREEZING. HOWEVER THE LOW LEVEL

AIRMASS WILL ALSO BE VERY DRY...SO IT IS POSSIBLE PRECIPITATION

ALOFT WILL EVAPORATE AND NOT REACH THE GROUND UNTIL AFTER TEMPS

WARM ABOVE FREEZING. IF PRECIP WERE INTENSE ENOUGH TO SATURATE THE

LOW LEVELS QUICKLY...SOME TYPE OF FREEZING OR FROZEN PRECIPITATION

WOULD BE THE RESULT FRIDAY MORNING.

THE CANADIAN IS INDICATING A SNOW/SLEET MIXTURE AND A HEALTHY

AMOUNT OF QPF FRIDAY MORNING...BUT I TRUST THIS MODEL THE LEAST IN

THE EXTENDED. THE GFS HAS SIGNIFICANTLY WARMER TEMPS ALOFT WHICH

MAKES SENSE GIVEN THE PACIFIC ORIGIN OF THIS SYSTEM. THE GFS WOULD

SUPPORT A FREEZING RAIN OR SLEET MIX THAT CHANGES TO RAIN DURING

THE DAY FRIDAY. THE ECMWF DID HAVE SOME LIGHT WINTRY PRECIP ON THE

0Z RUN...BUT THE 12Z CAME IN A LITTLE SLOWER WITH THE LOW AND THUS

HAD NO QPF UNTIL LATE FRIDAY WHEN TEMPS ARE MARGINALLY ABOVE

FREEZING. CONFIDENCE IN WINTER PRECIP OCCURRING IS LOW BECAUSE

THERE IS NOT A GOOD FORECAST SIGNAL OCCURRING IN THE SYNOPTIC

PATTERN. IN OTHER WORDS...THE 500MB PATTERN DOES NOT MATCH ONE OF

OUR CLASSIC SIGNIFICANT SNOW OR ICE PRODUCING PATTERNS. LAST WEEK

WE HAD A GOOD FORECAST SIGNAL IN THE SYNOPTIC DATA FOR WINTER

WEATHER POTENTIAL 8 TO 10 DAYS OUT BECAUSE MODELS WERE SHOWING

SIMILARITIES TO A SYNOPTIC PATTERN THAN PRODUCED OVER HALF OF OUR

SIGNIFICANT SNOW SYSTEMS OVER THE LAST 50 YEARS. MODELS DID CHANGE

THE FORECAST PATTERN SLIGHTLY OVER THE COURSE OF SEVERAL DAYS THAT

MADE SNOW UNLIKELY...BUT STILL IT WAS A GOOD HEADS UP THAT WINTER

POTENTIAL WAS INCREASING BECAUSE THERE WAS A STRONG CLIMATOLOGICAL

BASIS. THIS WEEK THE CLIMATOLOGY SIGNAL IS NOT ONE THAT PRODUCES

MAJOR WINTER EVENTS. INSTEAD WE HAVE AN EVENT THAT REQUIRES THE

PACIFIC SYSTEM TO ARRIVE IN A COMPARATIVELY TINY TEMPORAL WINDOW.

BECAUSE WITHOUT ANY MORNING PRECIPITATION...THE COLD AIR WOULD

MODIFY ABOVE FREEZING BY MIDDAY FRIDAY. WILL KEEP THE MENTION OF

POPS AS ALL LIQUID FRIDAY AND CONTINUE TO MONITOR THIS CLOSELY.

Yes, the next weekend is definitely wet, but temperature would be well above freezing when there's proper precip   :whistle: Like the AFD said "PRECIPITATION ALOFT WILL EVAPORATE AND NOT REACH THE GROUND UNTIL AFTER TEMPS WARM ABOVE FREEZING."

 

But sure it's interesting to watch!

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Morning briefing from Jeff:

 

Another strong arctic cold front is headed for the area.

 

Very cold temperatures expected Wednesday-Friday with a hard freeze possible Thursday morning.

 

Upper air pattern remains highly amplified with ridging deep into Alaska and a downstream trough across much of the western and central US. This continues to allow large arctic high pressure cells to develop over NW Canada and move SSE down the great plains into TX. This pattern looks to remain in place through this week allowing some of the coldest air of this winter to enter the region.

 

One such arctic boundary will be crossing the area this morning with gusty NW winds and cold air advection this afternoon. Temperatures will reach their highs around noon and then remain steady or fall slightly this afternoon under the influence of the upstream colder air mass moving into the region. Light freeze is likely for areas NW of US 59 Monday morning with winds weakening overnight and going near calm by sunrise Monday and a dry air mass in place. Lows will range from the 28-32 range NW of US 59 with temperatures warmer toward the coast in the 35-40 degree range where winds remain stronger overnight.

 

Brief warm up on Monday and Tuesday before a massive 1055mb arctic high comes crashing down the plains mid week.

 

Next strong arctic front will arrive late Tuesday and the air mass behind this boundary means business. Strong cold air advection will onset Tuesday afternoon and last into Thursday as surface pressures of nearly 1050mb build as far south as N TX…fairly impressive. Forecast models show a very dry and cold air mass building into the region on Wednesday with high temperatures struggling to get much into the 40’s even with sunny conditions. North winds of 15-25mph will produce wind chills into the 20’s and 30’s much of the day.

 

Wednesday night/Thursday AM:

Critical time period for potentially widespread damaging hard freeze will be Wednesday night into Thursday morning. Forecast models are showing a bitter cold and dry air mass in place by Wednesday evening and Thursday morning with GFS forecast dewpoints across the region in the 1’s and lower 10’s. Current guidance is showing hard freeze conditions for nearly all locations except the coastal counties Thursday AM (2 hours or greater below 25) with a few locations north of HWY 105 possibly falling into the upper 10’s. Temperatures could go even lower given the very low dewpoints that will be in place, but strong winds should continue into the overnight hours along with increasing upper level cirrus clouds ahead of the next storm system over the Baja region. Even with the winds and clouds, guidance is still showing a hard freeze Thursday morning and this freeze would likely be somewhat advective in nature which is usually more damaging in this area as the “greenhouse” method of vegetation protection generally fails for advective freezes. Wind chills Thursday morning will be well into the 10’s across the region!

 

Friday-Next Weekend:

Next upper level storm system moves across MX from Baja and toward TX on Friday. Cold arctic air mass will still be in place Friday with lows possibly once again falling below freezing. Surface layer is very dry as noted by the very low dewpoints…so while clouds will be thickening from the SW do not expect any precipitation while the surface temperatures are below freezing. Coastal trough is formed over the NW Gulf Friday in response to incoming system from the WSW in the upper levels. While the air mass should modify models are usually too fast in warming arctic cold domes suggesting with clouds and developing light rain Friday temperatures may be stuck in the 30’s. GFS tries to back door a surge a cold sub freezing arctic air into the region from the NNE on Sunday with widespread overrunning conditions in place. For now will keep everything liquid from Friday through next weekend awaiting better model consistency and indications on how the surface air mass over the region will behave as moisture returns.  

 

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GFS MOS guidance is coming in at 16°F for Thursday morning at DFW. The ECMWF actually warmed a bit since last run. However, surface pressures are still the same. With surface pressures prognosticated to get to approximately 1050mb or 31.00 inHg at that time (very impressive as noted above in Jeff's writeup) and very low dewpoints, would not be surprised to see the mercury totally bottoming out. Could very well be seeing some single digit temps, especially along the Red River and the very cold spots of North Texas. I could easily see DFW Airport dropping between 10°F and 15, if not colder with this. This could be one of the coldest mornings North Texas has seen in quite awhile.

 

For comparison, the record highest pressure at DFW Airport for January is 31.05 inHg set in 1962 in a pretty bad Arctic outbreak which resulted in low temps 12°F, 8°F, 7°F, 13°F January 9-12, 1962. The all time record pressure is 31.06 inHg set in December 1983 in one of our most severe Arctic outbreaks ever. This pressure resulted in low temps cratering to 5°F at DFW Airport. Our highest pressure in February was 31.00 inHg set in 1899 which resulted in our all time coldest surface temp of -8°F.

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