Texas Winter 2013-2014

[orangeblood]

Mr. Cavanaugh ladies and Gentlemen....brilliant discussion

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000
FXUS64 KFWD 012209
AFDFWD

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE FORT WORTH TX
409 PM CST SAT MAR 1 2014

.DISCUSSION...

REGARDING THE WINTER WEATHER ADVISORY ACROSS NORTH AND CENTRAL
TEXAS...WENT AHEAD AND EXPANDED THE ADVISORY SOUTH TO A CISCO TO
CLIFTON TO ATHENS LINE WITH THE AFTERNOON FORECAST PACKAGE. THE
BIGGEST IMPACTS FROM FREEZING RAIN AND/OR SLEET ACCUMULATIONS ARE
STILL EXPECTED TO OCCUR ALONG AND NORTH OF A LINE FROM GRAHAM TO
PLANO TO SULPHUR SPRINGS. POINTS SOUTH OF THIS LINE TO THE
SOUTHERN EDGE OF THE WINTER WEATHER ADVISORY ARE STILL EXPECTED
TO SEE IMPACTS FROM LIGHT ICE ACCUMULATIONS...BUT THESE IMPACTS
ARE EXPECTED TO BE FOCUSED ON ELEVATED SURFACES...IN PART DUE TO
THE VERY WARM TEMPERATURES ACROSS THE REGION TODAY. DETAILS
REGARDING THE FORECAST CONTINUE BELOW:

A 21Z SUBJECTIVE SURFACE ANALYSIS INDICATED A BOUNDARY LIFTING
SLOWLY NORTH TOWARDS THE RED RIVER WHERE MOST GUIDANCE INDICATES
IT WILL STALL OUT BY SUNSET. TEMPERATURES ACROSS NORTH TEXAS WERE
GENERALLY IN THE MID TO UPPER 70S FOR MOST LOCATIONS...WITH A
NOTABLE EXCEPTION SOUTHWEST OF THE DFW AREA...WHERE TEMPERATURES
SPIKED INTO THE MID TO UPPER 80S ALONG AN 850 MB THERMAL RIDGE.
WITH TEMPERATURES TOPPING OUT IN THE 70S TO 80S ON CONSECUTIVE
DAYS FOR MOST POINTS ACROSS NORTH AND CENTRAL TEXAS...SOIL
TEMPERATURES ARE WARM...AND THIS WILL PLAY AN IMPORTANT ROLE IN
OUR FORECAST OVER THE NEXT 24 HOURS.

TO OUR NORTH...21Z SURFACE OBSERVATIONS ACROSS SOUTHERN KANSAS AND
NORTHERN OKLAHOMA RANGED FROM THE LOWER TEENS TO THE MIDDLE 20S.
COMPARING THESE TEMPERATURES TO THE MORNING NAM 21Z FORECAST FOR
SURFACE TEMPERATURES INDICATED THAT THE NAM WAS RUNNING 8 TO 10
DEGREES TOO WARM WITH AIR ASSOCIATED WITH THE ARCTIC FRONT.
UNFORTUNATELY THE NAM IS THE COLDEST OF THE POPULAR OPERATIONAL
FORECAST MODELS...SO THERE ARE SOME SIGNIFICANT SHORT TERM SURFACE
TEMPERATURE ISSUES TO CONTEND WITH IN THE FORECAST MODELS MOVING
FORWARD. THE RAP IS DOING THE BEST JOB RESOLVING 21Z
TEMPERATURES...BUT THAT IS LARGELY DUE TO THE FACT THAT THE RAP
INGESTS NEW DATA EACH HOUR. AT ANY RATE...CONTINUED TO RELY UPON
THE NAM HEAVILY WITH THIS FORECAST PACKAGE...JUST LIKE THE
MIDNIGHT CREW...BECAUSE THE NAM IS THE COLDEST AND FASTEST WITH
THIS ARCTIC COLD FRONT OVER THE NEXT 24 HOURS.

DUE TO THE PRESENCE OF TWO BOUNDARIES IN THE AREA (THE NEARLY
STATIONARY FRONT NEAR THE RED RIVER...THEN THE ARCTIC FRONT TO THE
NORTH) IT WAS DIFFICULT TO TRACK THE SOUTHERN PROGRESS OF THE
ARCTIC FRONT EARLY THIS AFTERNOON. THIS IS PARTIALLY DUE TO MOSTLY
CLOUDY SKIES NORTH OF THE RED RIVER FRONT...AND PARTIALLY DUE TO
NORTHERLY WINDS EXTENDING FROM THE RED RIVER NORTH THROUGH KANSAS
MASKING THE WIND SHIFT ASSOCIATED WITH THE TRULY ARCTIC AIRMASS.
BASED ON HOURLY TEMPERATURE TRENDS...AT 21Z THE FRONT APPEARED TO
BE NEAR A LINE FROM CANADIAN TX TO WATONGA OK TO PONCA CITY OK.
TRACKING THIS FRONT WILL ALSO PLAY AN IMPORTANT ROLE IN THE
FORECAST FOR PRECIPITATION TYPE OVER THE NEXT 24 HOURS AS A FASTER
OR SLOWER FRONTAL PASSAGE COULD HAVE DRASTIC IMPACTS ON OUR
FORECAST AND IMPACTS.

TO THE FORECAST...THE COLD FRONT IS EXPECTED TO ARRIVE AT THE RED
RIVER JUST AFTER MIDNIGHT TONIGHT...PUSHING INTO THE DFW AREA
BETWEEN 3 AND 4 AM CST. THE FRONT IS EXPECTED TO PASS ACROSS WACO
AROUND 7 AM...AND THEN ACROSS PALESTINE AND TEMPLE/KILLEEN AN HOUR
LATER. THE FRONT IS EXPECTED TO BE SOUTHEAST OF THE FORT WORTH
CWA BEFORE NOON.

AHEAD OF THE FRONT...REGARDING THUNDERSTORM AND SEVERE WEATHER
CHANCES. PARAMETERS ARE THERE INDICATIVE OF A SEVERE THUNDERSTORM
THREAT WITH DEW POINTS IN THE LOWER TO MID 60S IN PLACE CURRENTLY
ACROSS MUCH OF CENTRAL TEXAS. MODELS INDICATE THAT THERE WILL BE
AROUND 1000 J/KG OF CAPE FOR STORMS AND KEEP LAYER BULK SHEAR OF
AROUND 50 KTS. TAKEN AT FACE VALUE THE INTERSECTION OF THIS
PARAMETER SPACE IS SUPPORTIVE OF ORGANIZED STORMS...PROBABLY
SUPERCELLS OR POSSIBLY MULTI-CELL CLUSTERS ASSUMING STRONG FORCING
ALONG THE COLD FRONT IS LARGELY RESPONSIBLE FOR RELEASING THE
POTENTIAL CONVECTIVE ENERGY INTO STORMS.

THE PROBLEM IS THAT THE CONSENSUS OF MODEL GUIDANCE SHOWS A LARGE
CAPPING INVERSION IN THE 850 TO 800 MB LAYER...WHICH IS QUITE
STOUT AT 300 TO 400 J/KG OF CONVECTIVE INHIBITION FOR SURFACE
BASED AIR PARCELS AHEAD OF THE FRONT. FORECAST SOUNDINGS DO
INDICATE THAT STRONG LIFT ASSOCIATED WITH THE ARCTIC FRONT WILL
LIFT AND COOL A LARGE CHUNK OF THIS CAPPING INVERSION...HOWEVER
THE CAP APPEARS TO BE CONSISTENTLY IN PLACE UNTIL 2-3 HOURS BEHIND
THE FRONT. THIS BEING THE CASE...THERE WOULD BE NEARLY A ZERO
CHANCE OF SURFACE BASED STORMS AND TORNADOES ACROSS THE CWA OUT
AHEAD OF THE FRONT TOMORROW MORNING. DAMAGING WIND MAY BE
POSSIBLE...HOWEVER STORMS ARE EXPECTED TO BECOME QUITE ELEVATED
BEHIND THE FRONT...SO ANY VERTICAL MOTIONS WITHIN THE FRONTAL
INVERSION ARE EXPECTED TO BE DAMPENED BY HIGH STABILITY. THAT
LEAVES A CHANCE FOR ELEVATED STORMS CAPABLE OF PRODUCING
HAIL...WHICH CANNOT BE RULED OUT AT THIS TIME. LEFT A MENTION OF
AN ELEVATED RISK FOR SEVERE STORMS ACROSS THE FAR SOUTHEASTERN CWA
FOR TOMORROW MORNING AS A RESULT IN OUR GRAPHICAL HAZARD IMAGES.

BEHIND THE FRONT...FORECAST SOUNDINGS ARE SUPPORTIVE OF SCATTERED
PRECIPITATION ASSOCIATED WITH PERSISTENT ISENTROPIC UPGLIDE AND
FRONTOGENETIC FORCING FOR ASCENT OVER ALL OF NORTH AND CENTRAL
TEXAS. WENT AHEAD AND BUMPED POPS UP TO 80 PERCENT FOR MOST
LOCATIONS SUNDAY MORNING AS CHANCES FOR ALL LOCATIONS TO RECEIVE
AT LEAST ONE HUNDREDTH OF AN INCH OF PRECIPITATION LOOKS VERY HIGH
AT THIS TIME. MOST PRECIPITATION SUNDAY MORNING IS EXPECTED TO BE
LIGHT...HOWEVER CANNOT RULE OUT SOME EMBEDDED THUNDERSTORMS AS AIR
PARCELS LIFTED FROM THE 900 TO 850 MB LAYER ARE CONSISTENTLY
FORECAST TO HAVE 3-500 J/KG OF POSITIVE CAPE. MORE WIDESPREAD
PRECIPITATION IS EXPECTED TO OCCUR SUNDAY AFTERNOON UNFORTUNATELY
AS A STRONG SHORTWAVE TROUGH CURRENTLY OVER SOUTHERN CALIFORNIA
SPREADS LARGE SCALE FORCING FOR ASCENT OVER THE CWA. THIS IS
UNFORTUNATE BECAUSE THE ARCTIC AIRMASS WILL BE THROUGH THE ENTIRE
CWA BY THIS TIME WITH SUB-FREEZING TEMPERATURES BUILDING QUICKLY
SOUTHEAST THROUGH THE AFTERNOON HOURS OF THE DAY.

DEPENDING ON HOW FAST TEMPERATURES FALL BEHIND THE FRONT...WE
SHOULD SEE A TRANSITION FROM RAIN SHOWERS TO FREEZING RAIN...TO
FREEZING RAIN MIXED WITH SLEET TO ALL SLEET THROUGHOUT THE DAY AS
THE ARCTIC AIRMASS CONTINUES TO BUILD INTO THE AREA FROM THE
NORTHWEST. AT THIS TIME HAVE THE BEST CHANCES FOR ACCUMULATING ICE
AND SLEET FOR LOCATIONS ALONG AND NORTH OF A LINE FROM GRAHAM TO
PLANO TO SULPHUR SPRINGS AS THESE LOCATIONS ARE MOST LIKELY TO
SPEND MOST OF THE DAY SUNDAY AT OR BELOW FREEZING. FROM THIS LINE
SOUTH TO A LINE FROM CISCO TO CLIFTON TO ATHENS (THIS INCLUDES THE
DFW METROPLEX)...EXPECT LESSER AMOUNTS OF ICE AND SLEET
ACCUMULATION SIMPLY BECAUSE THE SUB-FREEZING AIR IS SLOWER TO
BUILD IN...AND THESE AREAS SAW TEMPERATURES CLIMB ABOUT 10 DEGREES
HIGHER TODAY THAN LOCATIONS FURTHER NORTH.

ICE ACCUMULATIONS ARE VERY HARD TO PIN DOWN BECAUSE WE HAVE BEEN
SO WARM OVER THE PAST 48 HOURS. JUST LOOKING AT MODEL OUTPUT AND
FORECAST WATER EQUIVALENT PRECIPITATION AND CONVERTING THAT
DIRECTLY INTO ICE IS A VERY POOR ESTIMATE OF ICE ACCUMULATION FOR
THIS EVENT BECAUSE SOIL TEMPERATURES ARE IN THE MID TO UPPER 50S
ACROSS THE CWA. IT WILL TAKE QUITE A BIT OF TIME FOR SOIL
TEMPERATURES TO FALL...MEANING THAT A LARGE PORTION OF ANY LIQUID
PRECIPITATION THAT FALLS...EVEN WITH TEMPERATURES BELOW
FREEZING...WILL NOT STICK TO THE GROUND. ESTIMATING HOW MUCH
RAINFALL WILL RUN OFF VERSUS HOW MUCH WILL ACCUMULATE AS ICE IS
EXTREMELY DIFFICULT. AT THIS TIME FORECAST ACCUMULATION AMOUNTS
ARE APPROXIMATELY 25 PERCENT OF WHAT WE EXPECT TO FALL AS WATER
EQUIVALENT PRECIPITATION.

WHETHER THIS IS AGGRESSIVE OR CONSERVATIVE WILL DEPEND AT LEAST
PARTIALLY ON HOW FAST WE FALL BELOW FREEZING BEHIND THE ARCTIC
FRONT. FALLING BELOW FREEZING FASTER THAN EXPECTED WILL RESULT IN
GREATER IMPACTS ON AVERAGE. WE WILL MONITOR THE PROGRESS OF THE
FRONT THIS EVENING AND OVERNIGHT...AND IF IT LOOKS LIKE WE WILL
GET COLDER SIGNIFICANTLY FASTER...WE MAY HAVE TO UPGRADE SOME
PORTIONS OF THE ADVISORY INTO A WINTER STORM WARNING BEFORE SUNDAY
MORNING. AT THIS TIME THE MOST LIKELY SCENARIO IS ICE ACCUMULATION
AND IMPACTS MAINLY RELEGATED TO ELEVATED SURFACES...WHICH IS WHY A
WINTER WEATHER ADVISORY IS IN EFFECT AND NOT A WINTER STORM
WARNING AT THIS TIME. CURRENT THINKING IS THAT ONE TENTH TO ONE
QUARTER OF AN INCH OF SLEET IS POSSIBLE ACROSS THE ADVISORY
AREA...ALONG WITH LIGHT ICE ACCUMULATIONS OF LESS THAN ONE TENTH
OF AN INCH...MAINLY ON ELEVATED SURFACES.

WITH MOST ATTENTION FOCUSED ON SUNDAYS FRONT AND ASSOCIATED WINTER
WEATHER...HERE IS A QUICK SUMMARY OF THE REMAINDER OF THE FORECAST:

PRECIPITATION IS EXPECTED TO END FROM WEST TO EAST SUNDAY EVENING
ACROSS NORTH TEXAS. TEMPERATURES WILL REMAIN BELOW FREEZING ALL
NIGHT...MEANING ANY RESIDUAL WATER ON AREA ROADWAYS WILL FREEZE UP
CAUSING ADDITIONAL TRAVEL PROBLEMS.

MONDAY MORNING WIND CHILL VALUES WILL BE ZERO TO MINUS 5 DEGREES
FOR MUCH OF NORTH TEXAS...ASSUMING THIS DOES NOT CHANGE IN FUTURE
FORECASTS...WE WILL NEED A WIND CHILL ADVISORY FOR MUCH OF THE CWA
EARLY MONDAY MORNING TO ACCOUNT FOR THESE VERY COLD WIND CHILL
VALUES.

WITH COLD AIR IN PLACE...WE HAVE A CHANCE FOR LIGHT FREEZING RAIN
ACROSS CENTRAL TEXAS EARLY TUESDAY MORNING INTO THE LATE MORNING
HOURS OF THE DAY. WE WILL NEED TO WATCH THIS NEXT UPPER LEVEL
SYSTEM CLOSELY IN CASE IMPACTS ARE GREATER THAN CURRENTLY
FORECAST. CURRENTLY...ANY ICE ACCUMULATIONS ARE EXPECTED TO REMAIN
VERY LIGHT...ON THE ORDER OF ONE HUNDREDTH OF AN INCH.

WE WILL WARM UP FOR THE REMAINDER OF THE WEEK...BUT HAVE LOW RAIN
CHANCES IN THE FORECAST IN THE MIDDLE OF THE WEEK WITH YET ANOTHER
UPPER LEVEL STORM SYSTEM PASSING OVER THE REGION. THIS
PRECIPITATION IS EXPECTED TO REMAIN WARM ENOUGH FOR ALL RAIN AT
THIS TIME.

CAVANAUGH

[Ntxw]

He is the GOD of AFD discussions, no questions asked.

MONDAY MORNING WIND CHILL VALUES WILL BE ZERO TO MINUS 5 DEGREES
FOR MUCH OF NORTH TEXAS...ASSUMING THIS DOES NOT CHANGE IN FUTURE
FORECASTS...WE WILL NEED A WIND CHILL ADVISORY FOR MUCH OF THE CWA
EARLY MONDAY MORNING TO ACCOUNT FOR THESE VERY COLD WIND CHILL
VALUES.

This needs emphasis, March ladies and gentlemen.

[SouthernMet]

nam keeps a decent precip shield behind the front..
interesting that the nam is actually UNDER estimating the cold front by about 10 degrees as noted by the nws..

latest rap is extremely bullish and wetter which is no surprise..

ice storm warning up for se ok

[gpsnowman]

:uarrow: He is the GOD of AFD discussions, no questions asked.

MONDAY MORNING WIND CHILL VALUES WILL BE ZERO TO MINUS 5 DEGREES
FOR MUCH OF NORTH TEXAS...ASSUMING THIS DOES NOT CHANGE IN FUTURE
FORECASTS...WE WILL NEED A WIND CHILL ADVISORY FOR MUCH OF THE CWA
EARLY MONDAY MORNING TO ACCOUNT FOR THESE VERY COLD WIND CHILL
VALUES.

This needs emphasis, March ladies and gentlemen.

You are correct in that statement. Those wind chill values are insane for any point in winter. Goodness gracious.

[ravyrn]

Check out that temperature gradient in the panhandle! WOW!!!!

That's about 50F tempchange in about 30 miles.

[Ntxw]

https://imagizer.imageshack.us/v2/386x479q90/547/tqe2.jpg
Check out that temperature gradient in the panhandle! WOW!!!!

That's about 50F tempchange in about 30 miles.

Tomorrow should have some big temperature gaps in the state that I love talking about, single digits in the panhandle and 90s in the southwestern part! Always cool to see the extremes during these events!!

[gpsnowman]

Dalhart reporting freezing fog and 27 degrees. Here it comes!!!
Edit: I think we will need a report from the PWC Lubbock office soon with panhandle updates.

[Wntrwthrguy]

What are the models showing for the Austin area tomorrow through Tuesday?

[SouthernMet]

latest rap even wetter than the nam/euro/sref solution..

has a convective band well behind all the initial rain/freezing rain.. near the decatur-gainesville-mineral wells area with 3" per hour rates. (sleet) a trend to look out for an even more dangerous than the nam

[orangeblood]

Forecast low of 16 F tomorrow night in DFW Once again, it needs to be reiterated for future winters to come...The GFS is horrendous with an extremely cold dense shallow airmass, right now its some 8-10 hours behind schedule with the frontal passage along with a 20-25 deg F temp bust! Also, it looks like the climatology parameters placed in the GFS algorithm need to be reevaluated by the NWS, especially if a new normal is in store for our climate in the decades to come...maybe a low solar, Dalton Minimum - the Russians sure are adamant about it!!!

[orangeblood]

latest rap even wetter than the nam/euro/sref solution..

has a convective band well behind all the initial rain/freezing rain.. near the decatur-gainesville-mineral wells area with 3" per hour rates. (sleet) a trend to look out for an even more dangerous than the nam

Saw that, but we need to keep in mind how terrible it performed during the last winter event that came through here

[SouthernMet]

latest rap even wetter than the nam/euro/sref solution..

has a convective band well behind all the initial rain/freezing rain.. near the decatur-gainesville-mineral wells area with 3" per hour rates. (sleet) a trend to look out for an even more dangerous than the nam

Saw that, but we need to keep in mind how terrible it performed during the last winter event that came through here

it nailed that event. if I recall it backed off on showing that about 12 hours before and shifted any winter precip ne of the metro, where it was.

also the nws fd even said they trust the rap/nam over all the other guidance as the rap is the closest with current obs

[TheProfessor]

That would definitely cause trouble. Also with the last event the RAP was very inconsistent, if it continues a similar trend for the next 3-5 hours then it definitely needs to be considered.

[SouthernMet]

:uarrow: That would definitely cause trouble. Also with the last event the RAP was very inconsistent, if it continues a similar trend for the next 3-5 hours then it definitely needs to be considered.

rap is closest with current temps/obs and nam has shown a similar set up the past 3 runs. it's a plausible scenario

[Portastorm]

Dalhart reporting freezing fog and 27 degrees. Here it comes!!!
Edit: I think we will need a report from the PWC Lubbock office soon with panhandle updates.

I have the Lubbock office of the PWC on standby alert.

[weatherguy425]

Dalhart reporting freezing fog and 27 degrees. Here it comes!!!
Edit: I think we will need a report from the PWC Lubbock office soon with panhandle updates.

I have the Lubbock office of the PWC on standby alert.

Not the Lubbock PWC, but will I suffice?


Back door cold front currently hung-up on the Caprock. Slowing fronts over the past few weeks have led to compressional heating during the afternoons & temps soaring into the 80s ahead of the boundary. Obviously, today, has been the most extreme example. Saving grace for roads out here are the 75 -85 temps many saw this afternoon; cold and possibly wintry early Sunday regardless.

.... Going to be an early morning for myself.

[TheProfessor]

If the rap's trend continues, is there any chance NWS FWD issues a warning? My sister's friend is having a huge cheer competition with teams coming from all over the U.S and it might be best if they had to cancel it.

[gpsnowman]

Dalhart reporting freezing fog and 27 degrees. Here it comes!!!
Edit: I think we will need a report from the PWC Lubbock office soon with panhandle updates.

I have the Lubbock office of the PWC on standby alert.

Bueno. More than likely this will be the last arctic blast of this magnitude we will see so I am getting amped up with this system moving in. We may not do this again until December.
And you will suffice Weatherguy425!!!

[SouthernMet]

hate to say it but you can NOT compare this to the last "winter event" because we had dew points in the single digits and that was a very weak system.

this storm (as we saw in California) will have no problems qpf wise and will bring copious amounts of moisture with it behind the front.. The nws even warned of Thundersleet for the metro which is plausible, considering the convective band guidance has been showing.

also a difference fwiw with that event(or lack of) the sref never fully jumped on board with the idea of widespread winter precip in north texas, as it does now.

[Ntxw]

Just read that this winter is the 3rd coldest ALL-time in Chicago, Green Bay set its all time record for Sub-Zero days at 49 beating out 1976-77. Pretty incredible what the EPO/WPO can do or as my Colorado Mountain shuttle driver told me last month and I quote "its the Chem Trails and NASA radon testing that's causing the Jet Stream to curve up and over Alaska"....wonder what that guy's been smoking?

No one will doubt the power of the East Pacific Oscillation after this year (and really the past 3 years as the exact opposite happened with an opposite EPO). It was always there, we just never understood it. McFarland should be touted as one of the few who truly discovered the effects of the -EPO as his paper is just that, the many variations of the oscillation in negative territory. Many said the cold that resided in the late 1800s, early 1900s, 1970s, and 1980s can't be seen in such modern times on a consistent basis. The EPO seems to come in cycles, those colder eras featured predominate -EPO as we saw this year. I'll say it again, any forecast in future winters without consideration of the EPO leading the way should not be taken seriously, and overall the Pacific as well as ENSO is included but particularly the east Pacific.

Speaking of the EPO the daily's are still diving. Just look at this and follow the daily temperatures with it. Cold, thaw, cold. Just using this index alone if you were forecaster the entire winter and just used it on cold/warm you would've been seen as top notch.

2014 02 05 -345.43
2014 02 06 -360.66
2014 02 07 -256.20
2014 02 08 -205.53
2014 02 09 -175.48
2014 02 10 -117.77
2014 02 11 -51.46
2014 02 12 30.70
2014 02 13 119.82
2014 02 14 165.86
2014 02 15 224.44
2014 02 16 221.38
2014 02 17 172.69
2014 02 18 134.01
2014 02 19 84.99
2014 02 20 15.13
2014 02 21 -58.93
2014 02 22 -82.48
2014 02 23 -53.25
2014 02 24 -69.77
2014 02 25 -130.49
2014 02 26 -149.39
2014 02 27 -174.15