Texas Spring-2014

[WeatherGuesser]

:uarrow: Nice read. But what is the acryonym "CAISO"?

Shaping a clean, flexible grid
As the impartial grid operator for the bulk of the state’s power grid, the ISO opens access to the wholesale power market that is designed to diversify resources and lower prices. We are committed to preparing the wholesale market for implementing California’s environmental policies.

Understanding the ISO
The ISO operates a robust and reliable wholesale power system that balances the need for higher transmission reliability with the need for lower costs, and acts as a key platform to achieve California’s clean energy goals.

https://www.caiso.com/about/Pages/OurBu ... fault.aspx

[Portastorm]

Thanks WeatherGuesser!

[Ntxw]

Be careful what you wish for. All droughts in Texas ends in flood. To follow up on my post earlier today when you go to an extreme anomaly something extreme tends to happen. It can happen all at once and you may get more than you bargained for. From multi billion dollar drought to multi billion dollar flooding quickly. Just something to keep in the back of our minds as 72, 82, and 97 all featured costly flooding as a result of super El Nino's coming out of severe droughts as was 1957.

http://www.itouch.net/~radar/html/floods.html

[JDawg512]

Be careful what you wish for. All droughts in Texas ends in flood. To follow up on my post earlier today when you go to an extreme anomaly something extreme tends to happen. It can happen all at once and you may get more than you bargained for. From multi billion dollar drought to multi billion dollar flooding quickly. Just something to keep in the back of our minds as 72, 82, and 97 all featured costly flooding as a result of super El Nino's coming out of severe droughts as was 1957.

http://www.itouch.net/~radar/html/floods.html

Agreed, in fact I think its safe to assume especially in these times that a flood event will likely happen and to just be prepared for when it happens. Anyone who has lived in this part of the country for any extended period knows we can go from bone dry to inundating rains in a short amount of time. If the ground is dry and hard, a fast heavy amount of rainfall will not get a chance to soak in so it just washes away.

I'm kind of surprised that Bob Rose didn't mention the fact that this could be a strong El Niño or that we could see the effects much sooner than Fall if it is a powerful one but he is correct that not all El Niño's are the same. Having said that, what little history we have of the phenomenon has shown that Super El Niño's should give us much above normal rainfall.

[Ntxw]

I'm kind of surprised that Bob Rose didn't mention the fact that this could be a strong El Niño or that we could see the effects much sooner than Fall if it is a powerful one but he is correct that not all El Niño's are the same. Having said that, what little history we have of the phenomenon has shown that Super El Niño's should give us much above normal rainfall.

For sure they are not equal. There are dry El Nino's as well. But there is a strong correlation that the higher up the strength scale you go the more profound the presence become. If this is at least a moderate (more than likely) most likely a strong event it will be felt across the board. If a super Nino arises you can bet the later half of this year and/or the early part of next year will likely feature something extreme in regards to precipitation.

[TheProfessor]

I'm kind of surprised that Bob Rose didn't mention the fact that this could be a strong El Niño or that we could see the effects much sooner than Fall if it is a powerful one but he is correct that not all El Niño's are the same. Having said that, what little history we have of the phenomenon has shown that Super El Niño's should give us much above normal rainfall.

For sure they are not equal. There are dry El Nino's as well. But there is a strong correlation that the higher up the strength scale you go the more profound the presence become. If this is at least a moderate (more than likely) most likely a strong event it will be felt across the board. If a super Nino arises you can bet the later half of this year and/or the early part of next year will likely feature something extreme in regards to precipitation.

Which would great during the winter time. If a super El Nino occurs and next winter is as cold or colder then last winter, then I might get to see my dream of 24" of the white stuff!

[Ntxw]

Which would great during the winter time. If a super El Nino occurs and next winter is as cold or colder then last winter, then I might get to see my dream of 24" of the white stuff!

In theory it's nice, but in reality that is not usually the case. The stronger the Nino the more likely Canada will be overwhelmed with warm air. There is a reason most of the big Arctic blasts occurs in Ninas and neutrals (they just don't last long) as they favor mighty cold Canada. El Nino's do the opposite but are cooler in Texas because of persistent storms and cloud cover. They tend to favor snow though with any cold intrusions. Moderate El Nino that is west based and not traditional is more ideal. However it would be considered a -PDO super Nino which the only other specimen is 72-73 which was cold, sample size is too small.

[weatherdude1108]

Be careful what you wish for. All droughts in Texas ends in flood. To follow up on my post earlier today when you go to an extreme anomaly something extreme tends to happen. It can happen all at once and you may get more than you bargained for. From multi billion dollar drought to multi billion dollar flooding quickly. Just something to keep in the back of our minds as 72, 82, and 97 all featured costly flooding as a result of super El Nino's coming out of severe droughts as was 1957.

http://www.itouch.net/~radar/html/floods.html

Agreed, in fact I think its safe to assume especially in these times that a flood event will likely happen and to just be prepared for when it happens. Anyone who has lived in this part of the country for any extended period knows we can go from bone dry to inundating rains in a short amount of time. If the ground is dry and hard, a fast heavy amount of rainfall will not get a chance to soak in so it just washes away.

I'm kind of surprised that Bob Rose didn't mention the fact that this could be a strong El Niño or that we could see the effects much sooner than Fall if it is a powerful one but he is correct that not all El Niño's are the same. Having said that, what little history we have of the phenomenon has shown that Super El Niño's should give us much above normal rainfall.

Yeah, Bob Rose tends to be more cautious and thoughtful with his forecasts, basing them on history. But no telling with a potential Super Niño(?).

I have heard people over the years say this region (Texas in general) is in a perpetual drought, periodically interrupted by floods. Also knew a guy (native Texan) that said, "Texas has two seasons:
1. Summer; and
2. Cooler"

[somethingfunny]

Hey guys, the new FWD discussion is worth a read as it's the first to really go into detail about a potential severe weather outbreak on Sunday.

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE FORT WORTH TX
357 AM CDT FRI APR 11 2014

......

OUR NEXT WEATHER MAKER IS STILL IN THE PACIFIC OCEAN AND WILL MOVE
INTO CALIFORNIA TOMORROW. THIS UPPER LEVEL TROUGH WILL CONTINUE AN
EASTWARD TRACK RIGHT OVER THE SOUTHERN PLAINS ON SUNDAY. SEVERE
PARAMETERS WITH THIS SYSTEM HAVE INCREASED OVER THE LAST 24 HOURS
AND ARE NOW SUGGESTING THAT A SIGNIFICANT SEVERE WEATHER EVENT MAY
OCCUR IN NORTH CENTRAL TEXAS ON SUNDAY AFTERNOON. HOWEVER...THERE
ARE SOME DIFFERENCES IN THE MODELS AND SOME CONCERNS THAT LOWER THE
CONFIDENCE OF A SIGNIFICANT EVENT.

SUNDAYS SYNOPTIC SET UP WILL CONSIST OF THE UPPER LEVEL TROUGH
MOVING JUST ABOUT DIRECTLY OVER THE REGION...A SURFACE LOW MOVING
SOUTHEAST ACROSS THE CWA...A DRYLINE AND A STRONG COLD FRONT. THE
FIRST AND POSSIBLY MAIN FOCUS FOR THUNDERSTORM DEVELOPMENT WILL BE
ALONG THE DRYLINE. THE DRYLINE IS EXPECTED TO MOVE ACROSS OUR
WESTERN COUNTIES AS THE UPPER LEVEL TROUGH MOVES ACROSS THE REGION
DURING THE AFTERNOON HOURS. MOST OF THE MODELS BRING THE DRYLINE
TO JUST WEST OF THE I-35 CORRIDOR BY 00Z (7 PM) BUT THE NAM HOLDS
THE DRYLINE FARTHER WEST NEAR OUR WESTERN BORDER. THE MODELS AND
FORECAST SOUNDINGS ARE FORECASTING 1000-2500 J/KG OF CAPE WITH THE
HIGHEST CAPE NEAR THE DRYLINE...DECENT LAPSE RATES...AND CLOSE TO
50 KTS OF DEEP LAYER SHEAR ORIENTED PERPENDICULAR TO THE DRYLINE.
THE NAM IS HOLDING ONTO A SMALL CAP OVER THE REGION SUNDAY
AFTERNOON WHILE THE GFS ERASES THE CAP WITH THE TROUGH MOVING
OVERHEAD. THE CAP WILL BE PRETTY STRONG SATURDAY AND EARLY SUNDAY
WHICH MAKES THE GFS A LITTLE MORE TENTATIVE TO BELIEVE AND THE NAM
LOOK MORE REASONABLE. ALL OF THESE PARAMETERS SUPPORT SUPERCELL
DEVELOPMENT IF STORMS DEVELOP ALONG OR AHEAD OF THE
DRYLINE...MEANING A THREAT FOR LARGE HAIL AND DAMAGING WINDS.[i] IN
ADDITION...THE HODOGRAPHS ARE FORECAST TO BE STRONGLY CURVED WHICH
INDICATES A TORNADO THREAT IS ALSO POSSIBLE. ASIDE FROM THE
STRENGTH OF THE CAP...THE OTHER CONCERNING FACTOR IS THE SPEED OF
THE SHORTWAVE. ALL THE MODELS ARE CLOSE IN THE TIMING AND SPEED OF
THE UPPER LEVEL TROUGH...BUT THEIR SMALL DIFFERENCES ARE
SIGNIFICANT ENOUGH TO RAISE CONCERN ABOUT THUNDERSTORM DEVELOPMENT
ASSOCIATED WITH THE DRYLINE. THE ECMWF/GFS/CANADIAN/SREF ALL BRING
THE SHORTWAVE ACROSS THE REGION DURING THE AFTERNOON HOURS AND
ALREADY HAVE THE DISTURBANCE IN EASTERN OKLAHOMA BY 00Z (7 PM). AT
THIS SPEED...THE MAIN SYNOPTIC LIFT WOULD BE FAR AHEAD OF THE
DRYLINE AND MAY PREVENT THUNDERSTORMS FROM DEVELOPING.

GIVEN ALL THE FACTORS STATED ABOVE...OUR FORECAST WILL CALL FOR AT
LEAST ISOLATED SEVERE THUNDERSTORM DEVELOPMENT ALONG THE DRYLINE
SUNDAY AFTERNOON. THESE STORMS WILL HAVE A THREAT FOR
HAIL...DAMAGING WINDS...AND POSSIBLY TORNADOES. THE DRYLINE WILL
LIKELY BE MOVING ACROSS OUR WESTERN COUNTIES IN THE AFTERNOON
HOURS. IF THE SYSTEM SLOWS DOWN AND/OR THE NAM SOLUTION IS
REALIZED...THE LIKELIHOOD OF A MORE SIGNIFICANT OUTBREAK IS
POSSIBLE AND THE THREAT FOR STORMS WOULD SHIFT TO INCLUDE MORE OF
OUR WESTERN COUNTIES.

THE DRYLINE ON SUNDAY WILL MERGE WITH A COLD FRONT AS IT MOVES
IN FROM OKLAHOMA. THERE IS MORE UNCERTAINTY REGARDING IF
STRONG/SEVERE STORMS WILL AFFECT NORTH CENTRAL TEXAS ALONG THE
COLD FRONT SUNDAY NIGHT WITH THE LEAD SHORTWAVE NOW EXPECTED TO BE
EAST OF THE REGION. IF A SQUALL LINE DEVELOPS ALONG THE FRONT IN
OKLAHOMA...IT COULD MOVE ACROSS INTO TEXAS AND WOULD LIKELY IMPACT
OUR NORTHEASTERN COUNTIES. HOWEVER...THERE IS STILL EXPECTED TO BE
SOME ELEVATED PRECIPITATION WITH THE COLD FRONT AS IT MOVES
ACROSS THE REGION. THE FRONT IS LIKELY TO BE SHALLOW WITH WARM
AIR STILL OVERRUNNING THE LEADING EDGE. MUCH OF THE REGION WILL BE
IN WEAK RIDING ALOFT AND THEREFORE SUBSIDENT IN THE WAKE OF SUNDAY
AFTERNOONS TROUGH AND AHEAD OF ANOTHER TROUGH CROSSING NEW MEXICO.
HOWEVER...THE OVERRUNNING WARM AIR COULD BE LIFTED ENOUGH TO
PRODUCE SHOWERS AND THUNDERSTORMS ALONG AND BEHIND THE COLD FRONT
AND WILL KEEP POPS MENTIONED WITH THE FRONT SUNDAY NIGHT AND
MONDAY MORNING. THE HIGHEST POPS WILL BE OVER THE EASTERN HALF OF
THE CWA.

82/JLD

[Ntxw]

Some good news from the EnSo, for the third straight month the PDO has registered a positive reading all rising. Likely in response to the big El Nino. March's reading is the highest since before the -PDO era began in 2007.

[Portastorm]

Some good news from the EnSo, for the third straight month the PDO has registered a positive reading all rising. Likely in response to the big El Nino. March's reading is the highest since before the -PDO era began in 2007.

Yay!! Thinking about strong Ninos and their impact in Texas ... I was just looking at the fall/winter of 97-98 and saw lots of nice shades of blue (above average) across much of Texas on the NCDC precip maps from that period, getting me excited for a fall/winter full of precipitation. While I certainly do not wish for harm or damage to persons as a result of flooding, I think most of us in Texas are willing to face that risk as it comes with the promise of much welcomed rainfall. The drought has been absolutely devastating and anything which reverses its course, even temporarily, is a good thing in my book.

[TeamPlayersBlue]

My fam and i drove to PHX for Christmas in '97 and there was a HUGE ice storm that we came into as it just ended around ft. stockton. Ground was white from sleet, maybe a few inches. Then in PHX itself, not the northern part, they had sleet reported one of the days we were there. It was VERY cold. Highs didnt get out of the 40's and rain many days. That just doesnt happen in PHX.

[Ntxw]

The globals still show a frost/freeze threat for at least the northern half to third of the state. The latest freeze recorded at DFW is April 13th tied by the two big coming Nino's of 1957 and 1997. While I don't think the urban centers will record an official freeze if you have planting interest especially outside the immediate concrete jungle precautions would be wise.

The record low max on Monday is 55 and low is 35. DFW will come close to both of these readings. As far as severe weather I'm on the ledge. The set up isn't great and there is a plowing cold front that may arrive sooner and undercut thunderstorms but at the very least there should be a line somewhere.

[Jarodm12]

NTXW look at the latest nam the snow freezing precip line is getting awfully close to us lol

[Ntxw]

NTXW look at the latest nam the snow freezing precip line is getting awfully close to us lol

It's a little nuts. It has a large chunk of Texas below 30F which would set all kinds of records. A little too crazy, I'm just going to file it away until there is better support. But frost and freezes are definitely there.

[ravyrn]

^
Yeah we're paying close attention. We've got two gardens planted at my mom's and stepdad's that we're preparing to place tarps over if it looks like it'll frost/freeze. Luckily I've been slacking and haven't gotten my garden planted yet on their property.

[Jarodm12]

00utc gfs looking more like winter than spring with 132mb highs barreling down the south plains. This is a little hard to digest

[Ntxw]

There is just no words to put this into mind, just all kinds of wrong



GFS is friendlier, but not by much. Euro drives it deep like the NAM and I don't want to even talk about the UKmet. It has a southern plains (panhandle and OKlahoma winter storm and brings in cold. Keeps things chilled for awhile, US severe weather count will continue to be in the gutter with this kind of pattern.

[somethingfunny]

We've been treated to a Cavanaugh discussion.

AREA FORECAST DISCUSSION...CORRECTED
NATIONAL WEATHER SERVICE FORT WORTH TX
446 AM CDT SAT APR 12 2014

.DISCUSSION...

EARLY MORNING RADAR DERIVED WINDS ACROSS THE SOUTHERN PLAINS SHOW
A 40 KT LOW LEVEL JET ORIENTED OVER THE TX GULF COAST NORTH ACROSS
NORTH TX AND OVER CENTRAL OK. THIS JET WAS TRANSPORTING LOW-LEVEL
MOISTURE NORTH ACROSS THE REGION AS NOTED BY STRATUS STREAMING
NORTH ACROSS THE CWA AND 60 DEGREE DEW POINTS CREEPING NORTH OUT
OF SOUTH TX. 08Z/3AM WATER VAPOR SATELLITE IMAGERY SHOWED A
COMPACT SHORTWAVE TROUGH OVER SOUTHERN CA...MOVING SLOWLY EAST
TOWARDS AZ. A STRONGER SHORTWAVE TROUGH WAS NOTED OVER THE FAR
NORTHWESTERN CONUS...AND THIS FEATURE WAS DIGGING SOUTHEAST EARLY
THIS MORNING. THE 00Z FWD RAOB SHOWED A FAIRLY STOUT ELEVATED
MIXED LAYER (EML) IN PLACE OVER NORTH TX YESTERDAY EVENING. THIS
EML WAS DEFINED BY STEEP LAPSE RATES IN THE 800 TO 500 MB
LAYER...AND ALSO REPRESENTED A STRONG CAPPING INVERSION FOR
SURFACE BASED FREE CONVECTION.

TODAY...A 08Z SURFACE ANALYSIS INDICATED NO FRONTAL BOUNDARIES
NEAR NORTH TEXAS. WITH THE SHORTWAVE TROUGH STILL OVER SOUTHERN CA
EARLY THIS MORNING...AND NO OBVIOUS DOWNSTREAM UPPER LEVEL
DISTURBANCES EMBEDDED IN THE LARGELY ZONAL FLOW IN PLACE OVER THE
CENTRAL CONUS...WE SHOULD REMAIN FAIRLY DRY OVER THE NEXT 24
HOURS. A STRONG CAP IN PLACE COMBINED WITH THE LACK OF SIGNIFICANT
LARGE SCALE FORCING FOR ASCENT FAVORS A DRY FORECAST. WITH STRATUS
STREAMING NORTH ACROSS NORTH TX EARLIER THIS MORNING THAN
YESTERDAY...EARLY MORNING LOW TEMPERATURES WILL BE A FEW DEGREES
WARMER TODAY. HOWEVER A MORE WIDESPREAD AND THICKER STRATUS DECK
WILL BE SLOWER TO SCATTER OUT...WITH THE END RESULT BEING HIGH
TEMPERATURES TODAY VERY SIMILAR TO YESTERDAY.

TONIGHT...AS THE SOUTHERN CA SHORTWAVE TROUGH MOVES EAST...LARGE
SCALE FORCING FOR ASCENT WILL INCREASE OVER THE REGION. THE
CONSENSUS OF MODEL GUIDANCE IS THAT A SUBTROPICAL UPPER LEVEL JET
STREAK WILL BUILD OVER TX OUT AHEAD OF THIS TROUGH...CARRYING WITH
IT A PLUME OF UPPER LEVEL MOISTURE. ANY LOWER TO MID LEVEL
MOISTURE ASSOCIATED WITH THE SUBTROPICAL JET WILL BE SCOURED OUT
BY THE HIGHER TERRAIN OF MEXICO. HOWEVER...THIS UPPER LEVEL
MOISTURE COMBINED WITH AN INCREASE IN LARGE SCALE FORCING FOR
ASCENT WILL RESULT SCATTERED ELEVATED RAIN SHOWERS DEVELOPING AND
MOVING OVER NORTH TEXAS FROM SOUTHWEST TO NORTHEAST LATE TONIGHT
INTO SUNDAY MORNING. DUE TO THE STOUT EML IN PLACE...IT IS
DIFFICULT TO KNOW IF ANY OF THIS ELEVATED PRECIPITATION WILL
ACTUALLY REACH THE GROUND OR NOT. IF NOTHING ELSE...IT WILL
RESULT IN CLOUDY SKIES FROM MIDNIGHT TONIGHT THROUGH SUNDAY
MORNING.

WENT AHEAD WITH ONLY A 20-30 POP FOR THESE ELEVATED SHOWERS AT
THIS TIME BECAUSE THE EML DOES CONTAIN SOME VERY DRY AIR WHICH
WILL CAUSE MOST PRECIPITATION TO EVAPORATE BEFORE REACHING THE
GROUND. THE EXCEPTION TO THIS WILL BE IF SATURATION FROM THE TOP
DOWN RESULTS IN ISOLATED THUNDERSTORM ACTIVITY. WITH A NEARLY DRY
ADIABATIC LAYER OBSERVED FROM 800 TO 500 MB ON THE 00Z
SOUNDING...SATURATION FROM THE TOP DOWN MAY RESULT IN SOME FREE
CONVECTION WITH PERSISTENT LARGE SCALE FORCING FOR ASCENT
ASSOCIATED WITH THE APPROACHING SHORTWAVE TROUGH UPSTREAM. SO
BASICALLY...IF WE HAVE ELEVATED SHOWERS...NOTHING MORE THAN A
SPRINKLE WILL REACH THE GROUND. IF WE END UP WITH ISOLATED
THUNDERSTORMS...THE COVERAGE SHOULD BE HELD TO ABOUT 20 TO 30
PERCENT ACCOUNTING FOR THE CHOICE IN POPS IN THIS FORECAST FOR
LATE TONIGHT INTO SUNDAY MORNING. CLOUDY SKIES WILL KEEP LOWS IN
THE UPPER 60S FOR MOST LOCATIONS EARLY SUNDAY MORNING.

SUNDAY...THE SOUTHERN CA SHORTWAVE TROUGH IS EXPECTED TO MOVE
EAST-NORTHEAST ACROSS NORTH TX AND CENTRAL AND EASTERN OK BY
SUNDAY AFTERNOON. THIS IS EXPECTED TO RESULT IN A STRONG SURFACE
LOW LOCATED NEAR WICHITA FALLS BY LATE SUNDAY AFTERNOON...WITH A
WELL DEFINED DRYLINE TO ITS SOUTH...AND A COLD FRONT PUSHING
SOUTHEAST ACROSS THE REGION FROM NORTHWEST OF THE SURFACE LOW. THE
MODEL CONSENSUS FOR THE LOCATION OF THE DRYLINE IS NEAR A BOWIE TO
COMANCHE LINE AT THAT TIME. THE ELEVATED RAIN SHOWERS AND POSSIBLE
ISOLATED THUNDERSTORMS DESCRIBED ABOVE SHOULD HAVE MOVED OVER THE
FAR SOUTHEASTERN PORTIONS OF THE CWA AFTER 21Z...WITH CLEARING
SKIES FROM WEST TO EAST. THIS WINDOW OF CLEARING/MOSTLY SUNNY
SKIES IS PRETTY IMPORTANT BECAUSE IF IT DOES NOT PAN OUT...OUR
CHANCES FOR STORMS ALONG THE DRYLINE SUNDAY AFTERNOON ARE VERY
SMALL. AT ANY RATE...ASSUMING THIS AFTERNOON CLEARING DOES OCCUR
NEAR THE DRYLINE...TEMPERATURES SHOULD WARM INTO THE LOWER TO MID
80S...WHICH SHOULD NOT BE VERY HARD TO ACHIEVE WITH MORNING LOWS
IN THE UPPER 60S TO NEAR 70 DEGREES.

ASSUMING WE WARM AT LEAST INTO THE LOWER 80S NEAR THE DRYLINE
SUNDAY AFTERNOON...FORECAST SOUNDINGS INDICATE THAT SURFACE BASED
AIR PARCELS THAT ARE LIFTED WILL HAVE AROUND 2000 J/KG OF CAPE AND
ANYWHERE FROM 10 TO 20 J/KG OF CONVECTIVE INHIBITION (CIN) TO
OVERCOME TO RELEASE THE CAPE INTO FREE CONVECTION AND
THUNDERSTORMS. THEREIN LIES THE BIG FORECAST PROBLEM...WILL WE
HAVE SUFFICIENT LIFT TO OVERCOME THE CAP. SIMPLY LOOKING AT THE
FORECAST CIN MAKES THIS SEEM LIKE A VERY EASY CAP TO
OVERCOME...HOWEVER THE PROBLEM WITH THAT FORECAST CIN IS THAT THE
FORECAST MODELS HAVE ALREADY ACCOUNTED FOR A STRONG DEGREE OF LIFT
WHEN COMING UP WITH THAT NUMBER. SO WHAT THAT NUMBER REALLY MEANS
IS THAT THE MODELS DO NOT FAVOR SURFACE BASED CONVECTION
INITIATION NEAR THE DRYLINE IN THE FORT WORTH CWA SUNDAY
AFTERNOON. LOOKING AT THE RAW MODEL OUTPUT OF QPF OR SIMULATED
REFLECTIVITY FROM THE GFS/NAM/ECMWF SEEMS TO GENERALLY AGREE WITH
THAT ASSESSMENT. HOWEVER THE MODELS DO SEEM TO GENERALLY TRIP
THEIR SHALLOW CONVECTIVE SCHEMES NEAR THE DRYLINE INDICATING THAT
A CERTAIN SET OF CONDITIONS ARE MET FOR THESE MODELS TO TRIGGER
THEIR CONVECTIVE PARAMETERIZATION SCHEMES. THIS SIMPLY DOES NOT
OCCUR ON A LARGE OR LONG ENOUGH SCALE TO RESULT IN MODEL QPF OR
SIMULATED REFLECTIVITY.

SO WHAT DOES THIS MEAN? WELL THE FACT THAT THE OPERATIONAL MODELS
ARE TRIGGERING THEIR SHALLOW CONVECTIVE SCHEMES GENERALLY MEANS
THAT WE SHOULD SEE SOME CONVECTIVE ATTEMPTS NEAR THE DRYLINE
SUNDAY AFTERNOON. THE PROBLEM WITH DRYLINES IS THAT THEY FUNCTION
LIKE BACKWARDS FRONTS IN THAT THEIR STRONG FORCING FOR ASCENT
ACTUALLY OCCURS ON THE DRY SIDE OF THE BOUNDARY...WHERE IT/S
GENERALLY HOTTER. SO CONVECTION INITIATION USUALLY OCCURS IN THE
MID-LEVELS ABOVE THE LOW-LEVEL HOT AND DRY AIR...AND RELIES ON
THESE STORMS TO MOVE EAST OFF THE DRYLINE TO BECOME ROOTED IN THE
WARM SECTOR WHERE OUR SURFACE BASED CAPE OF 2000 J/KG RESIDES. THE
LATEST (00Z) TEXAS TECH WRF ACTUALLY SHOWS A VERY REASONABLE
DEPICTION OF WHAT WILL LIKELY HAPPEN SUNDAY AFTERNOON ACROSS NORTH
TEXAS. WITH OUR OPERATIONAL AND NON-CONVECTION ALLOWING MODELS
INITIATING THEIR CONVECTIVE PARAMETERIZATION SCHEMES NEAR THE
DRYLINE AND THE TEXAS TECH WRF ACTUALLY ALLOWING THIS CONVECTION
TO MOVE EAST OFF THE DRYLINE AND BECOME ROOTED IN THE WARM/MOIST
SECTOR...CONFIDENCE IN THUNDERSTORMS DEVELOPING ALONG THE DRYLINE
SUNDAY AFTERNOON IS ACTUALLY FAIRLY HIGH AT THIS TIME...DESPITE
THE LACK OF QPF SHOWN IN THE NAM/GFS/ECMWF AT 00Z. THE COVERAGE OF
STORMS WILL PROBABLY NOT BE THAT GREAT...BEING LIMITED BY THE
LINGERING CAP TO THE EAST OF THE DRYLINE. THINK THAT AT LEAST
ISOLATED AND POSSIBLY SCATTERED STORMS WILL DEVELOP ALONG THE
DRYLINE LATE SUNDAY AFTERNOON.

ASSUMING STORMS DEVELOP...THEY SHOULD BE SUPER-CELLULAR IN NATURE
AND AS A RESULT WILL QUICKLY BECOME CAPABLE OF PRODUCING SEVERE
WEATHER. LARGE HAIL AND DAMAGING WINDS ARE THE MOST LIKELY SEVERE
WEATHER HAZARDS WITH THESE STORMS...HOWEVER A TORNADO THREAT IS
POSSIBLE...ESPECIALLY IF WINDS NEAR THE DRYLINE DO NOT VEER TOO
STRONGLY TOWARDS THE SOUTHWEST. THE MORE BACKED (TOWARDS THE SOUTH
OR SOUTH-SOUTHEAST) THE SURFACE WINDS ARE...THE GREATER THE
TORNADO THREAT. AT THIS TIME MOST GUIDANCE VEERS THE WINDS TO THE
SOUTH-SOUTHWEST NEAR THE DRYLINE...SO THE TORNADO THREAT ACROSS
NORTH TEXAS DOES NOT APPEAR TO BE OVERLY HIGH AT THIS TIME. WE
WILL HAVE TO SEE WHAT THE WINDS ARE ACTUALLY DOING ON SUNDAY OF
COURSE. OTHERWISE...STORMS WILL TEND TO MOVE EAST OFF THE DRYLINE
LATE SUNDAY AFTERNOON AND MOVE TOWARDS THE INTERSTATE 35 CORRIDOR
BY SUNSET. KEPT POPS IN THE 40 TO 50 PERCENT RANGE DUE TO THE
EXPECTATION FOR A LIMITED COVERAGE OF STORMS. EVEN THOSE POPS MAY
BE A BIT HIGH...BUT SUPERCELLS ARE NOT SMALL STORMS...SO
PRECIPITATION COVERAGE OF 40 TO 50 PERCENT IS PROBABLY ABOUT AS
HIGH AS WE WILL GET AHEAD OF THE COLD FRONT.

THE PRIMARY REASONS THIS FORECAST SIDES WITH THUNDERSTORMS ALONG
THE DRYLINE AS OPPOSED TO A DRY FORECAST/THE CAP PREVENTING STORMS
FROM INITIATING ARE:

MORNING SHOWERS OR STORMS WILL HELP COOL THE STOUT LOW-LEVEL WARM
AIR INVERSION FASTER THAN LIFT ALONE. THE TEXAS TECH WRF SHOWS
THIS EVOLUTION NICELY.

THE ACTIVATION OF THE CONVECTIVE PARAMETERIZATION SCHEMES IN THE
OPERATIONAL MODELS USUALLY FAVORS STRONG MESOSCALE FORCING FOR
ASCENT...AND THE DRYLINE IS A GOOD SOURCE FOR THIS.

THE 00Z UPPER AIR ANALYSIS DID NOT INDICATE THAT THE EML SHOULD
STRENGTHEN SIGNIFICANTLY BETWEEN NOW AND SUNDAY AFTERNOON.
UPSTREAM 850 MB TO 700 MB TEMPERATURES WERE JUST NOT THAT MUCH
WARMER TO THE SOUTHWEST...MEANING THAT WITHOUT SOME STRONG
SUBSIDENCE THE CAP SHOULD NOT GET SIGNIFICANTLY STRONG THROUGH
ADVECTION ALONE.

REASONS THAT MAY ALLOW THE CAP TO WIN OUT:

CONVERGENCE ALONG THE DRYLINE IS NOT THAT STRONG. JUST BECAUSE THE
MODELS TRIGGER THEIR CONVECTIVE PARAMETERIZATION SCHEMES DOES NOT
MAKE CONVECTIVE ATTEMPTS ALONG THE DRYLINE REAL. THIS IS A
MESOSCALE CONCERN THAT CANNOT BE RESOLVED THIS FAR OUT...SO WE ARE
JUST TRUSTING WHAT THE MODELS ARE INDICATING HERE. IF THE SURFACE
WINDS ARE MORE VEERED THAN FORECAST...THERE IS LESS OF A CHANCE OF
INITIATION ALONG THE DRYLINE.

THE BEST FORCING FOR ASCENT ASSOCIATED WITH THE SHORTWAVE MOVES
EAST OF THE CWA BY 00Z. IF THE CAP WAS NOT SUFFICIENTLY WEAKENED
BY MORNING FORCING FOR ASCENT...OR EVAPORATIVE COOLING...IT WILL
JUST REMAIN TOO STRONG BY SUNDAY AFTERNOON FOR SURFACE BASED
STORMS TO DEVELOP.

LASTLY...IF WE JUST REMAIN CLOUDY ALL DAY NEAR THE DRYLINE...WE
JUST WILL NOT GET WARM ENOUGH FOR SURFACE LIFTED AIR TO HAVE ANY
CHANCE TO BECOME A THUNDERSTORM. ALL GUIDANCE SHOWS THIS
AFTERNOON CLEARING WEST OF INTERSTATE 35...BUT AGAIN...WE WILL
SEE WHAT HAPPENS SUNDAY AFTERNOON.

SUNDAY NIGHT...AN UNSEASONABLY STRONG COLD FRONT WILL MOVE
SOUTHEAST ACROSS NORTH TEXAS AFTER SUNSET. IF NOTHING ELSE...THIS
REPRESENTS OUR BEST CHANCE OF STORMS ACROSS THE CWA...EVEN IF THE
DRYLINE STAYS TOTALLY DRY SUNDAY AFTERNOON. ANY STORMS ALONG THE
COLD FRONT ACROSS NORTH TEXAS SHOULD BE ELEVATED ABOVE THE FRONTAL
BOUNDARY...SO ONLY LARGE HAIL WOULD BE A HAZARD ALONG THE FRONT.
STORMS ARE MORE LIKELY TO BE SCATTERED TO NUMEROUS ALONG THE
FRONT...SO WENT AHEAD WITH 60 POPS FOR MOST LOCATIONS EAST OF
INTERSTATE 35...WHERE THE DEEPER MOISTURE RESIDES. STRONG FORCING
FOR SUBSIDENCE BEHIND THIS FRONT SHOULD RESULT IN PRECIPITATION
ENDING FROM NORTHWEST TO SOUTHEAST SUNDAY NIGHT THROUGH MONDAY
MORNING.

MONDAY...MAINTAINED SOME LOW POPS OVER THE SOUTHEASTERN CWA AS
THE MUCH STRONGER NORTHWEST CONUS SHORTWAVE TROUGH MOVES OVER THE
REGION FROM WEST TO EAST. ANY MID-LEVEL MOISTURE WILL BE SQUEEZED
OUT OF THE ATMOSPHERE BY THIS FEATURE...RESULTING IN SOME LIGHT
PRECIPITATION OVER THE SOUTHEASTERN CWA ON MONDAY. KEPT SOME
MENTION OF ISOLATED THUNDER IN THE FORECAST FOR MONDAY AFTERNOON
IN THE FAR SOUTHEASTERN CWA AS THE NAM INDICATED THAT THE 850 MB
PORTION OF THE COLD FRONT STALLS OUT NEAR A PALESTINE TO ROCKDALE
LINE. THAT MAY RESULT IN SOME ELEVATED SHOWERS WITH EMBEDDED
THUNDERSTORMS...HOWEVER MOST OF THAT ACTIVITY SHOULD BE SOUTHEAST
OF THE CWA.

MONDAY NIGHT INTO TUESDAY MORNING...THE CONSENSUS OF THE RAW MODEL
OUTPUT FROM 00Z GUIDANCE WAS THAT SKIES WILL CLEAR OUT AS WINDS
BECOME LIGHT AFTER MIDNIGHT MONDAY NIGHT RESULTING IN AN IDEAL
RADIATIVE COOLING ENVIRONMENT. THE AIR BEHIND THIS FRONT IS
EXPECTED TO BE VERY COLD FOR THIS TIME OF YEAR WITH THE NAM
INDICATING H850 TEMPERATURES OF -5 DEG C OR BELOW NORTH OF
INTERSTATE 20. BY EARLY TUESDAY MORNING...MANY GUIDANCE MEMBERS
HAVE BELOW FREEZING TEMPERATURES FOR NON-URBAN AREAS ALONG AND
NORTH OF INTERSTATE 20...WITH TEMPERATURES IN THE LOWER TO MID 30S
ELSEWHERE. AT THE VERY LEAST...CONFIDENCE WAS HIGH ENOUGH TO
MENTION AREAS OF FROST IN THE FORECAST EARLY TUESDAY MORNING...BUT
WE WILL REALLY HAVE TO MONITOR FOR THE POTENTIAL FOR A FREEZE
ACROSS PARTS OF NORTH TEXAS. CHANCES OF FREEZING TEMPERATURES ARE
GREATEST NORTH OF INTERSTATE 20...BUT ARE POSSIBLE ANYWHERE AWAY
FROM THE URBAN HEAT-ISLAND EFFECT. WILL CONTINUE TO MONITOR THIS
CLOSELY IN FUTURE FORECASTS.

REMAINDER OF THE FORECAST...WE SHOULD REMAIN DRY UNDER RIDGING
ALOFT TUESDAY AND WEDNESDAY. OUR NEXT CHANCE FOR RAIN ARRIVES ON
THURSDAY AFTERNOON AS THE GFS AND CANADIAN INDICATE A STRONG
SHORTWAVE TROUGH WILL MOVE OVER THE REGION. THE ECMWF HAS A VERY
DIFFERENT SOLUTION...BUT JUST MAINTAINED LOW POPS AT THIS TIME AS
THE NAEFS GENERALLY SUPPORTS THE GFS AND CANADIAN.

CAVANAUGH

[Jarodm12]

http://mag.ncep.noaa.gov/Image.php?fhr= ... e=&ps=area

Is that frozen precip on the 06utc name high res at 60 hrs?