8 (edit- now tonight) days to first major Fall severe outbr

[Ed Mahmoud]

This worked for me fairly well in the Spring, but at 8 to 9 days out, Euro may be off. I look for vigorous 850 mb winds and divergent 500 mb flow at an angle, implying shear. Colorado, Oklahoma and Kansas.

[CrazyC83]

Could be the start of something. I sense a bunch of outbreaks this fall, and right up into the end of the year to finish a remarkable 2008. We had major outbreaks in January and February - what's to say we can't have one in December? There is no tornado season after all.

[PurdueWx80]

there may be too much low-level ridging along the gulf coast to allow enough moisture into the plains, at least according to the euro.

[Extremeweatherguy]

Things look interesting early next week...

http://www.nco.ncep.noaa.gov/pmb/nwprod ... n_120l.gif

[Ed Mahmoud]

Well, we're 5 days closer. Euro still sees good 850 mb winds and divergent 500 mb winds with some difference in direction.





As previously mentioned, moisture recovery may be a limiting factor.

[Ed Mahmoud]

Set up may be better the following day




The following NAM dewpoint chart is 12 hours earlier than the above Euro forecasts, because the NAM only goes out 84 hours, but clearly, NAM sees the returning moisture.

[Extremeweatherguy]

Could definitely be interesting.

Hopefully we get some good storms out of this in OKC! It has been well over 2 weeks since we have seen any rain at all.

[Ed Mahmoud]

Could definitely be interesting.

Hopefully we get some good storms out of this in OKC! It has been well over 2 weeks since we have seen any rain at all.

Not quite to OKC by Sunday evening...


Checked GFS sounding then for SPS, and dewpoints near 10ºC still a little meager for severe action.


Maybe Monday will be the big day.

[Extremeweatherguy]

Yeah, if the 12z GFS is correct, then Monday may be the most interesting day for central Oklahoma...

http://www.nco.ncep.noaa.gov/pmb/nwprod ... n_102l.gif

[Ed Mahmoud]

Have a Day 3 severe area (hotlinked, but I bet they'll be a Day 3 area East of here tomorrow, so no worries)

...CNTRL AND SRN PLAINS...

AXIS OF MODIFIED CP AIR WILL ADVECT NWD THROUGH THE SRN AND CNTRL
HIGH PLAINS ALONG A STRONG SLY LOW LEVEL JET. MEANWHILE...STEEPER
MID LEVEL LAPSE RATES WILL LIKELY SPREAD EWD OVER THE MOIST AXIS AND
CONTRIBUTE TO POTENTIAL FOR DESTABILIZATION DURING THE DAY. MODELS
SUGGEST CLOUDS AND ELEVATED CONVECTION COULD BEGIN FAIRLY EARLY OVER
WRN TX AS LIFT WITHIN UPPER JET EXIT REGION OVERSPREADS THE WARM
SECTOR. THE EXTENT AND EVOLUTION OF CLOUD COVER REMAINS THE PRIMARY
UNCERTAINTY AND COULD LIMIT DEGREE OF INSTABILITY AS WELL AS OVERALL
THREAT. HOWEVER...LOW LEVEL MOISTENING AS WELL AS HEIGHT FALLS
ATTENDING UPPER TROUGH WILL RESULT IN POTENTIAL FOR AT LEAST MODEST
DESTABILIZATION. STORMS MAY BECOME SURFACE BASED AND INTENSIFY ALONG
AND JUST EAST OF LEE TROUGH DURING THE AFTERNOON. INCREASING BULK
SHEAR ASSOCIATED WITH APPROACHING UPPER JET WILL SUPPORT ORGANIZED
STORM STRUCTURES INCLUDING SUPERCELLS AND BOWING LINE SEGMENTS.
OTHER STORMS MAY DEVELOP AS THE COLD FRONT OVERTAKES THE MOIST AXIS
OVERNIGHT WITH STORMS EVENTUALLY EVOLVING INTO AN MCS BEFORE
WEAKENING AS THEY ADVANCE EWD THROUGH PARTS OF OK OVERNIGHT.

..DIAL.. 10/03/2008

DAY 4-8 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0344 AM CDT FRI OCT 03 2008

VALID 061200Z - 111200Z

...DISCUSSION...

MODELS IN AGREEMENT THAT UPPER TROUGH WILL CONTINUE INTO THE CNTRL
AND SRN PLAINS MONDAY. INDICATIONS ARE THAT LEAD IMPULSE WILL LIFT
NEWD THROUGH THE CNTRL PLAINS AND MID MS VALLEY WHILE A SECONDARY
IMPULSE DROPS SEWD INTO BASE OF UPPER TROUGH THROUGH WRN AND CNTRL
TX. VERTICAL SHEAR PROFILES WILL REMAIN SUFFICIENT FOR ORGANIZED
STORMS ALONG SRN AND ERN PERIPHERY OF UPPER TROUGH. DEWPOINTS IN THE
60S WILL LIKELY ADVECT THROUGH WARM SECTOR. SOME THREAT FOR SEVERE
STORMS WILL EXIST FROM PARTS OF N CNTRL TX THROUGH CNTRL AND ERN OK
INTO THE LOWER MS VALLEY. WITH CONVECTION EXPECTED TO BE ONGOING
AHEAD OF COLD FRONT...UNCERTAINTY STILL EXISTS REGARDING WHERE THE
BOUNDARY LAYER WILL DESTABILIZE SUFFICIENTLY TO SUPPORT A MORE
SUBSTANTIAL SEVERE THREAT. HOWEVER...A RISK AREA MAY NEED TO BE
ADDED IN LATER OUTLOOKS.
BEYOND DAY 4...MODELS SUGGEST UPPER TROUGH WILL GRADUALLY WEAKEN
OVER TX AND THE LOWER MS VALLEY BEFORE BECOMING CUTOFF FROM THE NRN
STREAM. WHILE A THREAT FOR SEVERE STORMS MAY PERSIST THROUGH DAY 6
FROM PARTS OF ERN TX INTO THE LOWER MS VALLEY...CONFIDENCE IS NOT
HIGH ENOUGH AT THIS TIME TO INTRODUCE A HIGHER END OUTLOOK AREA.

..DIAL.. 10/03/2008

[Ed Mahmoud]

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE FORT WORTH TX
304 PM CDT FRI OCT 3 2008

.DISCUSSION...
SHORT WAVE ENERGY WILL MOVE EAST OF THE REGION THIS EVENING AS
A WEAK RIDGE BUILDS IN FROM THE WEST. EXPECT LINGERING SHOWERS IN
THE EAST TO DISSIPATE BY SUNSET WITH ONLY A FEW MID AND HIGH
CLOUDS TONIGHT.

HUMIDITY WILL INCREASE SATURDAY THROUGH SUNDAY AS A SURFACE TROUGH
DEEPENS LEE OF THE ROCKIES. MID LEVEL INSTABILITY WILL ALSO BE ON
THE INCREASE AS A POWERFUL UPPER LEVEL LOW PRESSURE SYSTEM ROTATES
ACROSS THE ROCKY MOUNTAIN WEST. ENERGY FROM THIS SYSTEM...COUPLED
WITH INCREASING MOISTURE WILL BRING A CHANCE OF SHOWERS AND
THUNDERSTORMS BEGINNING IN THE NORTHWEST ZONES SUNDAY NIGHT AND
SPREADING TO ALL OF NORTH TEXAS ON MONDAY. THE BEST CHANCE OF RAIN
AND THUNDERSTORMS WILL MOST LIKELY BEGIN MONDAY NIGHT AND CONTINUE
THROUGH TUESDAY WHEN A DRY LINE AND COLD FRONT MOVE ACROSS NORTH
TEXAS. VERTICAL WIND SHEAR AND INSTABILITY SHOULD BE ADEQUATE TO SUPPORT SOME SEVERE STORMS. RAIN AND THUNDERSTORM CHANCES WILL END FROM NORTHWEST TO SOUTHEAST TUESDAY NIGHT AS THE UPPER TROUGH AXIS TRANSLATES EAST AND DRIER/SUBSIDENT AIR FILTERS IN. THE REST OF THE WEEK SHOULD BE DRY AND SEASONAL WITH LOWS GENERALLY IN THE 50S AND 60S AND HIGHS IN THE 80S.

LOOKING BEYOND THIS FORECAST PACKAGE...IT APPEARS THAT THE WEATHER
PATTERN WILL BE ON THE ACTIVE SIDE AS WE MOVE INTO THE MIDDLE
HALF OF THE MONTH. THIS WILL BRING MORE COLD FRONTS AND PRECIPITATION
CHANCES.

79

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TULSA OK
300 PM CDT FRI OCT 3 2008

.DISCUSSION...
SHIFT IN PATTERN IS EVIDENT AS SOUTHERLY FLOW INCREASING TEMPERATURES
AND MOISTURE ACROSS THE REGION THIS AFTERNOON. SOME WEAK LIFT IS
APPARENT IN MID LEVEL CLOUDS AND ELEVATED SHOWERS TRYING TO
BREAK OUT ACROSS PORTIONS OF CENTRAL OKLAHOMA AND CENTRAL AND EAST
KANSAS. DOUBT THAT ANY IS REACHING SURFACE AT THIS POINT.

LOW LEVEL JET IS EXPECTED TO START HELPING CONVECTION AROUND MIDNIGHT. AS
IT STRENGTHENS...ELEVATED SHOWERS AND A FEW THUNDERSTORMS ARE EXPECTED
TO DEVELOP AS THIS FEATURE SLIDES EASTWARD OVER THE FORECAST AREA
DURING THE EARLY MORNING HOURS.

THE RAIN SHOULD GRADUALLY DIMINISH AS THE LOW LEVEL JET WEAKENS
DURING DURING THE MORNING HOURS.

STRONG UPPER SYSTEM COMES ASHORE OVER THE WEEKEND AND DIGS A HIGH
AMPLITUDE TROUGH TO THE WEST AND MOVES IT EASTWARD ACROSS THE REGION
DURING THE FIRST HALF OF THE WORK WEEK. THIS WILL CAUSE HIGH CHANCES
FOR SHOWERS AND THUNDERSTORMS. DIFFICULT TO SAY AT THIS
POINT WHAT THE SEVERE THREAT WILL BE BUT WILL DEFINITELY NEED TO
BE WATCHED.

[CrazyC83]

Still doesn't look like anything major yet, but could be fairly active. The big stuff is still to come surely.

[Ed Mahmoud]

there may be too much low-level ridging along the gulf coast to allow enough moisture into the plains, at least according to the euro.

That is why he is a professional...


SWODY2

...SRN HIGH PLAINS AREA...

ENELY TRAJECTORIES ALONG SRN PERIPHERY OF ERN U.S. SURFACE RIDGE HAS
LIMITED BOUNDARY LAYER MODIFICATION ALONG THE NRN GULF. FRIDAY
EVENING RAOBS INDICATED MODEST BOUNDARY LAYER MOISTURE WITH LOW 60S
DEWPOINTS OVER S TX. STRONG SLY GRADIENT FLOW EAST OF LEE TROUGH
WILL CONTRIBUTE TO NWD ADVECTION OF MODIFIED CP AIR THROUGH SRN
PLAINS WARM SECTOR WITH DEWPOINTS GENERALLY IN THE MID TO UPPER 50S.


CURRENT INDICATIONS ARE THAT CONVECTION MAY START EARLY SUNDAY FROM
NM THROUGH NRN PARTS OF W TX WITHIN REGION OF LIFT ASSOCIATED WITH
APPROACHING UPPER JET EXIT REGION. MODEST BOUNDARY LAYER MOISTURE
AND EXPECTED AREAS OF CLOUDS AND ONGOING PRECIPITATION WILL LIKELY
MITIGATE DESTABILIZATION POTENTIAL AND SERVE AS A LIMITING FACTOR
FOR A MORE ROBUST SEVERE THREAT. HOWEVER...SOME BREAKS MAY DEVELOP
OVER CNTRL AND SRN PARTS OF WRN TX AND CLOUDS MAY MIX FROM THE SW AS
THE BOUNDARY LAYER FLOW VEERS TO SWLY WEST OF TROUGH AXIS. STEEPER
MID LEVEL LAPSE RATES AND COOLER TEMPERATURES ALOFT ARE EXPECTED TO
SPREAD OVER MOIST AXIS LATER IN THE DAY...AND THIS WILL CONTRIBUTE
TO AT LEAST MARGINAL INSTABILITY WITH MLCAPE NEAR 500 J/KG POSSIBLE.


POTENTIAL WILL EXIST FOR STORMS TO INTENSIFY DURING THE DAY OVER WRN
TX AS THE ATMOSPHERE GRADUALLY DESTABILIZES. THE AGEOSTROPHIC
CIRCULATION WITHIN UPPER JET EXIT REGION WILL LIKELY MAINTAIN A
30-40 KT SLY LOW LEVEL JET OVER THE SRN AND CNTRL PLAINS. COUPLED
JET STRUCTURE WILL RESULT IN VERTICAL SHEAR PROFILES SUFFICIENT FOR
ORGANIZED STORMS. SEVERE THREAT SHOULD DIMINISH OVERNIGHT AS STORMS
CONSOLIDATE INTO AN MCS AND CONTINUE EAST THROUGH N TX AND OK.

[Extremeweatherguy]

Not looking to be a big event, but we could still get a strong line of storms through central Oklahoma on Monday morning. Some large hail and gusty winds may be associated, but an outbreak of tornadoes or widespread warnings is not anticipated at this time.

[jinftl]

Can the countdown to this outbreak go in reverse....i.e.,4 days past the 8 day countdown to the severe outbreak...oh wait, everything has been pushed back 2 days so w are now 4 days past the 8 day countdown plus 2 days.

[Ed Mahmoud]

Can the countdown to this outbreak go in reverse....i.e.,4 days past the 8 day countdown to the severe outbreak...oh wait, everything has been pushed back 2 days so w are now 4 days past the 8 day countdown plus 2 days.

Or something.

[CrazyC83]

Beyond this, there are some small lows going through around October 7 (Tuesday) and again on October 12, but they don't look too conducive to big stuff. The big issue is the fact that the systems are just too weak (the October 12 storm will also be quite far north, and unlike on October 18 last year, it doesn't appear to be picking up Gulf moisture to help it - it will be in dewpoints near 50 rather than low 60s in its vicinity).

[Ed Mahmoud]

"Major" in the thread title turned out to be just a tad bit of an overstatement.

But the SPC does have part of West Texas and New Mexico in a slight risk area.

[Ed Mahmoud]

Maybe we can re-set the 8 day clock over again. An EastPac cyclone will have been entrained into the trough next Sunday per the Euro. Might actually limit instability if mid/high levels are relatively more moisture laden than the low levels, but we have some directional shear, and a decent low level jet.

[RL3AO]

BULLETIN - EAS ACTIVATION REQUESTED
TORNADO WARNING
NATIONAL WEATHER SERVICE MIDLAND/ODESSA TX
437 PM CDT SUN OCT 5 2008

THE NATIONAL WEATHER SERVICE IN MIDLAND HAS ISSUED A

* TORNADO WARNING FOR...
SOUTHEASTERN WARD COUNTY IN WEST TEXAS...
WEST CENTRAL CRANE COUNTY IN WEST TEXAS...

* UNTIL 515 PM CDT

* AT 434 PM CDT...NATIONAL WEATHER SERVICE METEOROLOGISTS DETECTED A
SEVERE THUNDERSTORM CAPABLE OF PRODUCING A TORNADO NEAR ROYALTY...
OR 13 MILES SOUTH OF MONAHANS...MOVING EAST AT 18 MPH.

* THE TORNADO WILL AFFECT THE FOLLOWING LOCATIONS...
TUBBS CORNER...

Nice radar signature on this cell