February Ends Warm and Dry

[srainhoutx]

The 12Z NAM as come in a bit weaker with the storm system for Thursday and a bit further S. We may not know until early Thursday just how this situation may play out as the disturbance is still offshore of the W Coast...

[srainhoutx]

The 12Z GFS continues the southward trend and suggests some storms possibly along a dryline across N/Central/ and perhaps parts of SE TX and points N and E. As Ed pointed out earlier, the bigger threat may well be Sunday through Tuesday of next week as a much stronger disturbance heads E from the W Coast. The chances of active weather are beginning to increase right on cue.

[srainhoutx]

It looks like the 12Z Euro suggests a bit stronger disturbance for Thursday. I suspect we will need to watch that storm system closely as the models just don't seem to have a good handle on just what may happen. I'd keep an eye on any dryline development and any super cell activity that may develop along with a possible MCS somewhere from N Central TX and points E from Wednesday night into Thursday.

[srainhoutx]

I'd keep an eye on Sunday/Monday and possibly into Tuesday, depending on timing, for a significant severe outbreak for the Southern Plains including parts of TX...

[wxman666]

Some will probably disagree with how drastic the coverage is on this map, nonetheless, TWC has placed the entire east half of TX, including the Houston area, in the threat on Thursday. Needless to say, this has heightened my awareness on this and I will be watching it even closer this week. Interestingly, they also mention this will be a very active severe wx season for Dixie Alley.

http://www.weather.com/outlook/weather- ... -21?page=3

[wxman57]

Some will probably disagree with how drastic the coverage is on this map, nonetheless, TWC has placed the entire east half of TX, including the Houston area, in the threat on Thursday. Needless to say, this has heightened my awareness on this and I will be watching it even closer this week. Interestingly, they also mention this will be a very active severe wx season for Dixie Alley.

http://www.weather.com/outlook/weather- ... -21?page=3

The map just indicates a chance of thunderstorms here. It appears the severe thunderstorm threat is well to our north. Best chance of storms is between around 3pm-6pm Thursday. We have a chance of thunderstorms here about every day from May through September. No big deal.

[srainhoutx]

The 12Z WRF suggests some possible severe storms from near Waco and points N and E tomorrow afternoon near and ahead of the surface low. Our area still looks very capped, but perhaps a skinny line of showers/storms can develop and just maybe we can get a bit of rain that we badly need. The storm on Sunday/Monday has sped up on most guidance and is still looking like a stronger disturbance, but capping again looks to be an issue for our area limiting any chance of thunderstorms. We will see if any changes occur over the next couple of days as a southward trend still continues regarding storm track.

[sleetstorm]

What worries me with this spring-like weather is that winter-like temperatures may come back with retribution, please pardon the metaphor, sometime next month/April.

[wxman57]

Main upper-level lifting will pass well to our north tomorrow (KS/OK). Nothing to indicate any severe storms near us, maybe not even enough lift for thunderstorms. A few showers with the frontal passage, most likely. No cold air behind the front, as it's just Pacific air. Long-range models indicate that winter is over for us. That's not to see we won't see any additional cold fronts before June, just that our chances of any freezing temps and/or precipitation are fading fast.

[srainhoutx]

The experimental NCEP 4.0 km WRF-NMM suggests some possible Super Cells near Central TX shifting E along and E of the dryline. Hmmm...

[srainhoutx]

Sorry Ed. I'm a bit busy and was on the iphone at that moment. Hour 28 on composite reflect caught my eye...

[wxman666]

Some will probably disagree with how drastic the coverage is on this map, nonetheless, TWC has placed the entire east half of TX, including the Houston area, in the threat on Thursday. Needless to say, this has heightened my awareness on this and I will be watching it even closer this week. Interestingly, they also mention this will be a very active severe wx season for Dixie Alley.

http://www.weather.com/outlook/weather- ... -21?page=3

The map just indicates a chance of thunderstorms here. It appears the severe thunderstorm threat is well to our north. Best chance of storms is between around 3pm-6pm Thursday. We have a chance of thunderstorms here about every day from May through September. No big deal.

Wxman57: I know, I posted that last night and by the time you saw it, it had changed.

[wxman666]

Latest day 2 outlook from SPC shifts slight risk further south than earlier this morning.

http://www.spc.noaa.gov/products/outlook/day2otlk.html

[wxman57]

If you advance the loop through frontal passage, it just shows light showers moving across southeast Texas tomorrow afternoon. That's probably all we'll see.

[wxman666]

Playing with some of the sim radars at the NCEP experimental site from the ARW and whatsthat, and the 18Z GFS, and a common theme seems to be a line of showers and storms, apparently forced on the dry line, that does its best to barely miss metro Houston.

Ed: Thanks for the insight. I will certainly be watching. I have kind of gotten to the point now after living here 8 years where I tend to take the forecasts with a grain of salt, and keep watching until I know for sure what's going on. One thing I have learned is that sometimes things are downplayed and then just when I let my guard down, we're hit with the storm. Other times, the forecasts turn out right so it can be hard to tell.

[wxman57]

I can't shrink that above picture enough to be meaningful.

In Firefox, right-click the image and choose "View Image". Then just hold down the "Ctrl" key while scolling the wheel on your mouse to shrink or enlarge an image.

[srainhoutx]

Not a lot of change with the latest SPC Outlook...

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0658 AM CST THU FEB 24 2011

VALID 241300Z - 251200Z

...THERE IS A MDT RISK OF SVR TSTMS OVER PARTS OF THE LWR MS AND LWR
TN VLYS...

...THERE IS A SLGT RISK OF SVR TSTMS SURROUNDING THE MDT RISK
AREA...FROM THE SRN PLNS ENE INTO THE LWR OH VLY...

...SYNOPSIS...
POTENT SHORTWAVE TROUGH NOW OVER ERN NM EXPECTED TO CONTINUE ENE
INTO ERN OK BY EVE AND INTO THE MID OH VLY BY 12Z FRI. AT THE
SFC...LOW NOW EVOLVING IN NW TX/SW OK SHOULD STRENGTHEN AND
ACCELERATE ENE INTO N CNTRL AR BY EVE...BEFORE UNDERGOING MORE
SUBSTANTIAL DEEPENING AND REACHING NRN WV EARLY FRI. PACIFIC COLD
FRONT NOW EMERGING OVER W TX SHOULD CONTINUE STEADILY E ACROSS TX
AND SRN OK. THE FRONT SHOULD OVERTAKE AN AXIS OF PRE-FRONTAL
CONFLUENCE EXPECTED TO EVOLVE OVER E TX AND THE ARKLATEX LATER
TODAY...AND CONTINUE E TO THE WRN SLOPES OF THE SRN/CNTRL
APPALACHIANS BY 12Z FRI.

COMBINATION OF STRENGTHENING WIND FIELD AND ASCENT WITH PROGRESSIVE
UPR IMPULSE...CONTINUED MOISTURE INFLOW /WITH PW INCREASING TO AOA
1.50 INCHES/...AND DIURNAL HEATING EXPECTED TO SUPPORT AN OUTBREAK
OF SVR TSTMS OVER PARTS OF AR/TN AND ADJACENT STATES LATER TODAY
INTO TONIGHT.

...SRN PLNS ENE INTO THE LWR TN VLY/LWR OH VLYS...
STRENGTHENING SSWLY LOW-LVL FLOW IN WARM SECTOR OF DEEPENING SFC LOW
WILL TRANSPORT SUBSTANTIAL MOISTURE NWD AND EWD INTO THE LWR MS AND
TN VLYS LATER TODAY...AND INTO THE LWR/MID OH VLY BY TONIGHT...WITH
PW VALUES LOCALLY EXCEEDING 1.75 INCHES. COUPLED WITH POCKETS OF
MODERATE SFC HEATING...SUFFICIENT INSTABILITY SHOULD DEVELOP TO
SUPPORT NUMEROUS BANDS/CLUSTERS OF TSTMS AS 90-120 METER MID-LVL
HEIGHT FALLS WITH UPR IMPULSE SWEEP ENEWD.

TSTMS NOW OVER NW TX AND SW THROUGH NE OK SHOULD INCREASE COVERAGE
AND POSSIBLY STRENGTH THROUGH MIDDAY AS LARGE SCALE ASCENT CONTINUES
ENE INTO MOISTURE-RICH ENVIRONMENT. RELATIVELY STEEP MID-LVL LAPSE
RATES AND SIZABLE CLOUD-LAYER SHEAR SUGGEST POTENTIAL FOR HAIL AND
POSSIBLY SHORT-LIVED BOWING SEGMENTS WITH HIGH WIND AS THE STORMS
MOVE/DEVELOP MAINLY ENEWD.

ADDITIONAL TSTMS EXPECTED TO FORM TOWARD MIDDAY OR BY EARLY AFTN
ALONG CONFLUENCE AXIS FROM ERN OK/WRN AR SSW THROUGH THE ARKLATEX
INTO E TX. A FEW STORMS ALSO MAY FORM NEAR INTENSIFYING WARM FRONT
EXTENDING ENE FROM THE AR SFC LOW INTO WRN/MIDDLE TN. BOTH THE
CONFLUENCE AXIS STORMS AND THOSE ALONG THE WARM FRONT WILL HAVE
ACCESS TO THE RICHEST MOISTURE INFLOW AND MAXIMUM SFC HEATING OF THE
PERIOD...WITH POCKETS OF SBCAPE EXPECTED TO BE AOA 1250 J PER KG.
IN ADDITION...LOW- TO MID-LVL SHEAR WILL INCREASE SUBSTANTIALLY BY
LATE IN THE DAY AS CORE OF 50+ KT 700 MB SW FLOW ASSOCIATED WITH NM
UPR IMPULSE OVERSPREADS REGION. THUS...THE AR AREA STORMS WILL POSE
A THREAT FOR HIGH-IMPACT SVR WEATHER INCLUDING SUPERCELLS WITH
BOWING SEGMENTS/HIGH WINDS...LARGE HAIL...AND POSSIBLY STRONG
TORNADOES. THE TORNADO THREAT WOULD APPEAR TO BE GREATEST FROM LATE
THIS AFTN THROUGH EARLY TONIGHT NEAR WARM FRONT OVER CNTRL/NERN AR
AND WRN/MIDDLE TN...WHERE 200-300 M2/S2 0-1KM SRH WILL EXIST INVOF
DEEPENING SFC LOW.

THE STORMS SHOULD EVOLVE INTO AN EXTENSIVE QLCS BY MID-EVE...WITH
OVERALL LINE MOVEMENT TO THE ENE ACROSS TN/LWR OH VLYS...AND
DEVELOPMENT SWD INTO LA/MS/AL THROUGH THE OVERNIGHT. A CONTINUING
THREAT DMGG WIND AND ISOLD TORNADOES LIKELY WILL PERSIST WELL INTO
THE NIGHT...ESPECIALLY NEAR TRACK OF SFC LOW ...AND FARTHER S IN
AREA OF GREATER SFC-BASED BUOYANCY IN MIDDLE TN...MS...AND NRN/WRN
AL.

..CORFIDI/GARNER.. 02/24/2011

[srainhoutx]

MESOSCALE DISCUSSION 0123
NWS STORM PREDICTION CENTER NORMAN OK
0747 AM CST THU FEB 24 2011

AREAS AFFECTED...NWRN TX THROUGH SW AND CNTRL OK

CONCERNING...SEVERE THUNDERSTORM WATCH 12...

VALID 241347Z - 241545Z

THE SEVERE WEATHER THREAT FOR SEVERE THUNDERSTORM WATCH 12
CONTINUES.

SOME THREAT FOR HAIL AND ISOLATED STRONG WIND GUSTS WILL CONTINUE
FOR THE NEXT COUPLE HOURS FROM NWRN TX INTO CNTRL OK.

DEEPER ASCENT ASSOCIATED WITH NEWD EJECTING LEAD SHORTWAVE TROUGH
HAS OVERSPREAD NWRN TX THROUGH OK. THIS HAS RESULTED IN A
SIGNIFICANT INCREASE IN THUNDERSTORM COVERAGE ALONG AND JUST EAST OF
EWD ADVANCING PACIFIC FRONT FROM NWRN TX INTO SWRN OK AS WELL AS
ALONG AND NORTH OF SWD ADVANCING POLAR FRONT ACROSS CNTRL THROUGH
NERN OK. THE 12Z NORMAN RAOB SHOWS 1500 J/KG MUCAPE AND A LAYER OF 7
C/KM LAPSE RATES BETWEEN 700-500 MB...BUT WITH WEAKER LAPSE RATES
ABOVE 500 MB. LATEST OBJECTIVE ANALYSIS INDICATES A NARROW CORRIDOR
OF MODERATE INSTABILITY REMAINING FROM NWRN TX INTO CNTRL OK.
POTENTIAL STILL EXISTS FOR A FEW CELLS TO PRODUCE HAIL AND ISOLATED
STRONG WIND GUSTS...BUT THREAT IS BECOMING INCREASINGLY MARGINAL AS
THE MORE UNSTABLE PORTION OF WARM SECTOR IS OVERTURNED.

..DIAL.. 02/24/2011


ATTN...WFO...FWD...OUN...SJT...

[srainhoutx]

The 12Z WRF suggests some possible showers/storms across our Northern areas later this afternoon/early evening. We will need to keep an eye on Central TX as the day progresses for any T storm activity that may fire ahead of the dryline...

[TexasMetBlake]

NAM: with slightly veered surface (SSW) and 850 mb (SW at ~ 1 km) flow it looks like tornado potential across the warm sector in Arkansas, while non-zero, may be mitigated tomorrow afternoon. Usually want 45 degrees of turning between 850 mb and 500 mb to get those large looping hodographs indicitive of extreme shear. Since instabilitiy will be marginal, primary severe threat will be high winds. For us, looks like the severe potential will stay north. Soon we'll see those red cherries begin to spring up out west (super cells) out along the dryline in west Texas.