Chase 2009 Day 3 Discussion Tx Panhandle

[Paul Sherman]

As per the 17z Update We are Overnighting in Childress (Which is now a Wet County Nick F)

A few reasons for this, firstly some Overnight Storms are Possible from an Increasing Low Level Jet from 06z.

Secondly we are in a good position for the Chase Target for Tuesday and will be hanging out in the I27 Corridoor, Upslope Storms have an outside Chance of becoming Tornadic if they can gather Supercell Status. More will become Apparant when we wake up in the Morning.

DAY 2 CONVECTIVE OUTLOOK

NWS STORM PREDICTION CENTER NORMAN OK

1225 PM CDT MON APR 27 2009

VALID 281200Z - 291200Z

...THERE IS A SLGT RISK OF SVR TSTMS SRN HIGH PLAINS AND NRN TX...

...SYNOPSIS...

SHORTWAVE TROUGH...CURRENTLY LOCATED OVER THE CENTRAL PORTIONS OF

THE COUNTRY...WILL EJECT NEWD AND DEAMPLIFY AS IT MERGES WITH A

STRONGER TROUGH MOVING EWD ACROSS SERN CANADA. THESE SYSTEMS WILL

PUSH A COLD FRONT EWD THROUGH THE NERN QUARTER OF THE COUNTRY ON

TUE...WHILE THE WRN PORTION OF THE FRONT STALLS ACROSS THE MIDDLE

MS/SRN PLAINS REGION. ANOTHER TROUGH DIGGING SWD THROUGH ORE/NRN CA

IS FORECAST TO EVOLVE INTO A BROAD UPPER LOW IN THE PACIFIC NW. THIS

WILL RESULT IN BROAD CYCLONIC FLOW WITH EMBEDDED SHORTWAVE TROUGHS

EXTENDING FROM THE SWRN STATES NEWD INTO CENTRAL/SRN PLAINS.

...SRN HIGH PLAINS AND NRN TX...

FRONT IS EXPECTED TO STRETCH ACROSS NRN TX WWD IN THE SRN TX

PANHANDLE DURING THE MORNING. SCATTERED CONVECTION MAY BE OCCURRING

ALONG AND NORTH OF THE FRONT...ESPECIALLY ACROSS THE TX PANHANDLE

...WHERE STRONGER FORCING IS EXPECTED DUE TO STRENGTHENING LOW LEVEL

JET/ISENTROPIC LIFT. COMBINATION OF STEEP MID LEVEL LAPSE RATES AND

MOISTENING ADVECTION ABOVE THE BOUNDARY LAYER INDICATE A MARGINAL

THREAT FOR SEVERE HAIL WITH ELEVATED THUNDERSTORMS DURING THE

MORNING.

HOWEVER...THE COMBINATION OF DIURNAL HEATING AND DEWPOINTS IN THE

50S IN NM AND 60S IN TX SHOULD RESULT IN MODERATE INSTABILITY

...WITH MLCAPES FROM 1000 TO 2000 J/KG ACROSS THE SLIGHT RISK AREA.

A SHORTWAVE TROUGH IS PROGGED TO MOVE INTO THE WRN TX BY

AFTERNOON...AND STORMS ARE LIKELY TO DEVELOP ALONG NWD DRIFTING E-W

ORIENTED FRONT...REMNANT BOUNDARIES FROM MORNING CONNECTION AND IN

MOISTENING UPSLOPE FLOW REGIME ACROSS ERN NM. VEERING WINDS IN THE

LOWER 3KM COMBINED WITH MODERATE 40 KT WSWLY MID LEVEL WINDS WILL

CONTRIBUTE TO EFFECTIVE SHEAR NEAR 40 KT AND SUPERCELLS DURING THE

AFTERNOON/EVENING HOURS. ALTHOUGH THERMODYNAMIC PROFILES LOOK MOST

FAVORABLE FOR LARGE HAIL...STRONG TURNING IN THE LOWER 1-2 KM AND A

RELATIVELY MOIST BOUNDARY LAYER FAVORS SOME TORNADO DEVELOPMENT IN

ERN NM AND THE TEXAS PANHANDLE.

OVERNIGHT...ELEVATED STORMS ARE EXPECTED TO DEVELOP NWD IN ZONE OF

STRONG WARM ADVECTION...THOUGH WEAK INSTABILITY SHOULD LIMIT SEVERE

POTENTIAL WITH THESE STORMS.

...MID MS VALLEY NEWD INTO THE NEW ENGLAND...

THOUGH CONVECTION IS EXPECTED TO BE ONGOING ACROSS PORTIONS OF THE

MID MS/TN AND INTO THE OH VALLEYS IN THE MORNING...WEAK LAPSE RATES

SHOULD RESULT IN A LOW THREAT FOR SEVERE. IN THE NERN STATES

...LIMITED INSTABILITY WILL EXIST AHEAD OF ADVANCING COLD FRONT.

THIS INSTABILITY ALONG WITH AFTERNOON HEATING AND CONVERGENCE MAY

SUPPORT SCATTERED STORMS ALONG THE FRONT. DESPITE WEAK INSTABILITY

...MODERATE/STRONG UNIDIRECTIONAL WSWLY WINDS INDICATE A THREAT OF

ISOLATED WIND GUSTS BETWEEN 18Z-01Z.

Paul S

[Nick F]

Lol Paul, funny how suddenly Childress County is wet - maybe a new mayor/leader who likes a drink?

We now have today as a day 1 outlook, looking like a jog SW for the team if they want supercells - maybe Big Spring across to Odessa and down towards San Angelo - though you are probably good to play further north towards Lubbock too if you don't want to go that far south, though at lunchtime I will have another look at my own target area. Main threat likely to be large hail, but an isolated risk of a tornado given some strong shear vectors and helicity values across west Texas later today.

GFS CAPE and Preciptn. 00z Weds:

WRF 0-3km and 0-1km helicity looking strong enough for tornadoes in W TX:

DAY 1 CONVECTIVE OUTLOOK

NWS STORM PREDICTION CENTER NORMAN OK

0100 AM CDT TUE APR 28 2009

VALID 281200Z - 291200Z

...THERE IS A SLGT RISK OF SVR TSTMS FROM THE SRN HIGH PLAINS INTO

THE TX BIG BEND REGION/HILL COUNTRY...

...SYNOPSIS...

A LARGE CLOSED MID/UPPER LEVEL LOW DEVELOPING OVER THE NWRN STATES

EARLY TODAY IS EXPECTED TO REMAIN CENTERED OVER WA/ORE THIS FORECAST

PERIOD. FARTHER NE...A SHORT WAVE TROUGH IS EXPECTED TO TRACK FROM

NRN ONTARIO/UPPER GREAT LAKES REGION EWD THROUGH QUEBEC AND NY/NEW

ENGLAND. MEANWHILE...A BROAD ZONE OF WSWLY FLOW ALOFT...WITH

SEVERAL EMBEDDED SHORT WAVE TROUGHS AND/OR WEAKER IMPULSES...WILL

EXTEND FROM THE SWRN STATES ACROSS THE CENTRAL/SRN PLAINS TO THE

NERN STATES/MID ATLANTIC STATES TODAY.

A COLD FRONT WILL SPREAD E/SEWD THROUGH THE NERN STATES AND OH

VALLEY REGION TODAY. THE WRN EXTENT OF THIS BOUNDARY EXTENDING FROM

NRN TO WEST CENTRAL TX AT 12Z TODAY WILL SHIFT SLOWLY NWD REACHING

SRN OK TO THE SRN TX PANHANDLE LATE TUESDAY NIGHT.

...SRN HIGH PLAINS/N TX TO PARTS OF CENTRAL PLAINS...

WATER VAPOR IMAGERY INDICATED A SHORT WAVE TROUGH TRACKING ENEWD

ACROSS ERN AZ AT 28/06Z. THIS FEATURE IS EXPECTED TO TRACK ACROSS

THE SRN HIGH PLAINS THIS MORNING...AND MAY BE THE IMPETUS FOR SOME

ONGOING TSTMS...SOME POSSIBLY PRODUCING HAIL...AT THE START OF THE

FORECAST PERIOD OVER FAR NERN NM INTO THE TX PANHANDLE. SUBSIDENCE

IN THE WAKE OF THIS TROUGH/MID LEVEL WARMING SUGGESTS NEW CONVECTIVE

DEVELOPMENT MAY BE INHIBITED UNTIL LATE AFTERNOON OR EVEN EARLY

EVENING AS THE NEXT SHORT WAVE TROUGH APPROACHES THE SRN HIGH PLAINS

TOWARD 29/00Z.

SSELY LOW LEVEL WINDS WILL INCREASE THROUGH THE DAY FROM THE LOWER

RIO GRANDE VALLEY INTO THE SRN HIGH PLAINS WITH LOW LEVEL MOISTURE

/SURFACE DEWPOINTS IN THE 60S/ RETURNING NWWD INTO THE SRN HALF OF

THE SLIGHT RISK AREA BY AFTERNOON. STEEP LAPSE RATES ATOP THE LOW

LEVEL MOISTURE RETURN COMBINED WITH SURFACE HEATING ARE EXPECTED TO

RESULT IN MODERATE INSTABILITY ALONG AND S OF THE NWD MOVING SURFACE

FRONT. STRONGEST INSTABILITY IS PROGGED FROM THE TX HILL COUNTRY

WWD TO THE PECOS RIVER VALLEY.

SELY LOW LEVEL WINDS VEERING TO 30-40 KT WSWLY MID LEVEL WINDS WILL

RESULT IN STRONG EFFECTIVE BULK SHEAR /AROUND 50 KT/ IN THE SAME

REGION WITH THE STRONGEST INSTABILITY SUPPORTING SUPERCELLS WITH ANY

TSTM DEVELOPMENT THAT OCCURS BY LATE AFTERNOON. GIVEN THE STRENGTH

OF THE SHEAR/INSTABILITY...VERY LARGE HAIL AND ISOLATED TORNADOES

WILL BE POSSIBLE ACROSS SW TX THIS AFTERNOON INTO THE EVENING.

A NOCTURNAL SSELY LLJ VEERING OVERNIGHT TO MORE SLY IS EXPECTED TO

DEVELOP ALONG THE FULL EXTENT OF THE HIGH PLAINS AFTER DARK. MODELS

SUGGEST AN MCS SHOULD DEVELOP ACROSS ERN NM/TX PANHANDLE THIS

EVENING WITHIN ZONE OF INCREASING LOW LEVEL WAA...WITH HAIL AND

STRONG WIND GUSTS BEING THE INITIAL THREATS. HAIL SHOULD BECOME THE

PRIMARY THREAT LATER TUESDAY NIGHT AS THE LLJ VEERS AND THE ACTIVITY

BECOMES MORE ELEVATED AND POSSIBLY REACHES WRN/SWRN OK AFTER 29/06Z.

[Paul Sherman]

Hi Nick

Yes latest Updated Charts now looking like SW Of Lubbock around the BIG Spring Area, will await a few more Updates but this looks a Solid Bet at the Moment, Large Hail in that part of the World is Legendary

Paul S

[Roger J Smith]

Cool air mass has undercut the Gulf moisture and pushed the fronts back to the west overnight. Northeast winds at Guadalupe Pass indicate that the fronts will be slow to return east. Would agree that severe storm development is only likely in areas south of I-20 and probably fairly far west, like around 20-50 miles south of Odessa TX, when the tropical air begins to flow north and encounters the frontal boundary. The dry line will stay about 100 miles west of the TX-NM border until almost end of daylight, and the Lubbock area will only be getting into severe weather after darkness falls, in fact there could be a major outbreak overnight in the TX panhandle. But for today's daylight hours I would suggest a location near Fort Stockton to Iraan TX in the Pecos valley. No rush, it probably won't develop until 4-6 pm.

Further north daylight severe activity may be as far west as Roswell NM. In these low-level cold wedge situations, the weather over the TX panhandle often remains overcast and cool despite rising thickness values, and the current low cloud and fog situation could hang in east of the TX-NM border until almost 6 pm.

Looking ahead to Wednesday, the overnight severe outbreak will probably redevelop across e KS, central OK and the I-20 corridor of west TX again, and given the grunge and cloud factors, today's target area may not be too far from where action may redevelop later Wednesday, possibly more like San Angelo to Brownwood area.

[Paul Sherman]

I am liking the SE New Mexico area Roger, going to drift down to Hobbs (NM) And see if we can get some Upslope Firing, Agree the Pecos region looks good for Discrete Supercell Storms earier in the day around 22z to 00z, but the AMA To CDS To LBB Area should Light up later from 02z onwards. Hope to get the Team some Nice Supercell Structure today and Tornado Chances are at 5% as per the SPC

Paul S

[Nick F]

Sent a text to Ian a few hours ago saying I would head towards SE New Mexico border, say through Seminole, TX and maybe over the border. Not sure he got the text?

Anyway, 12z WRF shows some good strong helicity values west and southwest of the Lubbock area. MUCAPE looks reasonable for enough instability for supercells:

- 0-1km and 0-3km helicity 00z Weds

- MUCAPE 00z Weds

A classic upslope environment today for perhaps some discrete supercells to develop where the team are heading.

SPC update at 1610:

...S CNTRL AND SW TX INTO THE SRN HI PLNS...

A SERIES OF WEAK DISTURBANCES IN THE CYCLONIC FLOW EXTENDING FROM

OFF THE BAJA CA CST ENE ACROSS AZ/NM AND NRN MEXICO WILL AFFECT THE

SRN AND CNTRL PLNS THROUGH EARLY WED. BECAUSE OF THEIR CLOSE

SPACING/LOW AMPLITUDE...NONE APPEAR LIKELY TO BE ACCOMPANIED BY

STRONG UVV. HOWEVER...THERE REMAIN INDICATIONS IN BOTH THE

SATELLITE AND MODEL DATA THAT AT LEAST SOME DEGREE OF SUBSIDENCE

WILL PREVAIL OVER THE SRN HI PLNS THIS AFTN...AND THAT A MODEST

INCREASE IN LARGE SCALE FORCING FOR ASCENT MAY OCCUR LATE IN THE

DAY/EARLY TONIGHT.

DESPITE WEAK LARGE SCALE FORCING...IT SEEMS LIKELY THAT COMBINATION

OF SFC HEATING AND PERSISTENT/INCREASINGLY MOIST SELY LOW LVL

UPSLOPE FLOW BENEATH DEEP EML WILL SUPPORT SCTD STORM DEVELOPMENT BY

LATE AFTN FROM THE TRANS PECOS REGION OF TX NNW INTO E CNTRL NM

ALONG WESTERN EDGE OF LOW LEVEL CLOUD FIELD. 35-40 KT WSWLY MID LVL

FLOW AND ABSENCE OF STRONG LOW LVL CONVERGENCE MECHANISMS SUGGEST

THAT PREDOMINANT STORM MODE WILL BE DISCRETE SUPERCELLS. THESE

COULD PRODUCE LARGE HAIL AND TORNADOES...ESPECIALLY IN SW TX. OTHER

STORMS...POSSIBLY WITH HAIL...COULD FORM ALONG W/E FRONTAL SEGMENT

OVER S CNTRL TX.

LOW LVL MOISTURE WILL CONTINUE TO SPREAD NNW ACROSS W TX AND ERN NM

INTO THE TX PANHANDLE THIS EVE/EARLY WED AS ELONGATION OF PACIFIC NW

UPR LOW ENHANCES LEE TROUGH OVER THE CNTRL/NRN HI PLNS AND FRONT

REDEVELOPS N ACROSS REGION. THIS SETUP MAY FOSTER CONTINUED NWD

DEVELOPMENT OF STORMS THROUGH THE NIGHT INTO WED MORNING.

MODERATE...RELATIVELY COOL CYCLONIC MID LVL FLOW SHOULD MAINTAIN A

POTENTIAL FOR SUPERCELLS WITH LARGE HAIL AND POSSIBLY A COUPLE

TORNADOES.

Still alot of cloud cover to contend with, but clearance further west should see it break hopefully:

[Tony Gilbert]

Hi Paul and guys. Hope you are having a good chase so far!

My input is optional at this point. Not optimistic for today! Could do alot of running around with very little to show at the end of it; Heavy cap in place and may not weaken at all ie.Your zone. All the models are saying this ATM. Periphery storms are likely to fire by late afternoon west of Odessa but I do not see them gaining strength under the current climate. Opinion!

Stay in Lubbock and watch a much better outlook unfold for tomorrow. Thats just my opinion! good luck

[Nick F]

Still Stubborn cloud cover over Sern TX Panhandle as shown by the team's live stream and the vis. satellite images.

if they are going to be hopefull of something to chase maybe worth heading over the border into NM towards Carlsbad where the skies may clear but you still have the moisture - dryline is just west of Carlsbad and Roswell. If they pop over the border they'll still be in range for tomorrow's likely severe risk over TX Panhandle

At Hobbs just over into NM the dew point is a respectable 57F:

helicity still favourable:

Though like Tony says, a strong cap to break which will struggle given the lack of UVV forcing (Upward Vertical Velocity) and will rely on some strong sfc heating and upslope lift to break it. though this may be beneficial in storms being isolated and discrete.

Hourly mesoscale charts show there's SBCAPE given the moisture (best under clearer skies to W and SW) but a strong cap over TX Panhandle (shown by blue area):

[anvilhead]

Ihope cloud does clear, but it seems to have been pretty consistant east of the dryline all day. http://www.rap.ucar.edu/weather/satellite/...&duration=5

I've fired up gr3 - the only sign of any cell development in that area is to the NW of Lubbock - I believe this is where the caprock is, but cant quite remember ..

[Nick F]

SPC's 1939z update acknowledges cap in place supressing convection ... but suggests subsidence may weaken from the west and allow destabilisation

DAY 1 CONVECTIVE OUTLOOK

NWS STORM PREDICTION CENTER NORMAN OK

ISSUED BY 15TH OWS SCOTT AIR FORCE BASE IL

0239 PM CDT TUE APR 28 2009

VALID 282000Z - 291200Z

...THERE IS A SLGT RISK OF SVR TSTMS S CNTRL AND SW TX INTO THE SRN

HI PLNS...

SHORT WAVE RIDGE MOVING THROUGH THE SOUTHERN ROCKIES AND ASSOCIATED

SUBSIDENCE IS SUPPRESSING CONVECTION OVER EASTERN NM AND SW TX AT

THIS TIME. VISIBLE IMAGERY INDICATES LOW CLOUDS OVER EASTERN NM HAVE

BEEN GRADUALLY DIMINISHING FROM THE WEST ALLOWING INCREASED

HEATING/DESTABILIZATION ALONG THE WESTERN EDGE OF THE MOISTURE AXIS.

POTENTIAL FOR THUNDERSTORM DEVELOPMENT EXPECTED TO INCREASE AFTER

SHORTWAVE RIDGE MOVES FURTHER EAST LATE THIS AFTERNOON/EVENING.

VEERING WIND PROFILES WITH HEIGHT CONTINUE TO SUPPORT RISK FOR A FEW

SEVERE STORMS AS DISCUSSED IN PREVIOUS OUTLOOK.

...15 OWS...

[John Hanrahan]

Paul S Here

Sitting Tight at Brownfield at the Moment, As Tony and Nick say not going to plan at the moment so no point driving all day for little reward so will sit tight for the time being, liking the Clearance to our West at the Moment in SE New Mexico and if anything does fire then we might have something to Chase in the next few hours, Cloud cover has been a pain all day. Will watch the area around Lubbock as well in the next hour.

[Tony Gilbert]

Good move Paul. Obviously make the most of whatever potential is available for today without any long journey, maybe!

RUC currently suggests that some small pockets of convection could break through the cap but the cap will thin close up again!...Maybe just too strong for weak underlined convection to break through and then keep the break open?

Tony

[NL]

MD for eastern New Mexico, concerniong severe potential.

MESOSCALE DISCUSSION 0616

NWS STORM PREDICTION CENTER NORMAN OK

0346 PM CDT TUE APR 28 2009

AREAS AFFECTED...ERN NM

CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE

VALID 282046Z - 282215Z

CONVECTION DEVELOPING OVER THE HIGHER TERRAIN OF ERN NM MAY

EVENTUALLY POSE A LIMITED SEVERE THREAT.

ISOLATED STORMS HAVE BEGUN DEVELOPING OVER THE HIGHER TERRAIN OF ERN

NM...AS SELY UPSLOPE FLOW CONTINUES TO YIELD WEAK ASCENT. THE SELYS

AT LOW LEVELS -- BENEATH 30 TO 40 KT WSWLY FLOW AT MID-LEVELS -- IS

ALSO YIELDING A WIND PROFILE SUPPORTIVE OF ORGANIZATION/MID-LEVEL

ROTATION.

DAYTIME HEATING W OF THE LOW CLOUD BAND HAS CONTRIBUTED TO MODEST

DESTABILIZATION /500 TO 1000 J/KG MIXED-LAYER CAPE PER LATEST

OBJECTIVE ANALYSIS/. WITH UPSLOPE FLOW WITHIN THIS

SLOWLY-DESTABILIZING THERMODYNAMIC ENVIRONMENT LIKELY TO SUPPORT

ADDITIONAL STORM DEVELOPMENT...AND WITH SHEAR SUFFICIENT FOR

ROTATING UPDRAFTS...SEVERE THREAT SHOULD SLOWLY INCREASE THROUGH THE

AFTERNOON. WHILE STORMS SHOULD REMAIN SOMEWHAT ISOLATED...HAIL AND

LOCALLY-GUSTY WIND POTENTIAL WITH STRONGER/SUPERCELL STORMS MAY

WARRANT THE EVENTUAL ISSUANCE OF A WW ACROSS THIS AREA.

[Aunt Sally]

Hi, we're sat in a car park of a hotel in Brownfield, Texas where apparently Reed Timmer and the Discovery Channel are staying tonight - unfortunately no room for us as we're not that important!! Just waiting in the area until the storm starts!

Tammy

[anvilhead]

Good move Paul. Obviously make the most of whatever potential is available for today without any long journey, maybe!

RUC currently suggests that some small pockets of convection could break through the cap but the cap will thin close up again!...Maybe just too strong for weak underlined convection to break through and then keep the break open?

Tony

I asume we're hoping that the shortwave is being underestimated then ?

[chionomaniac]

How frustrating all that cloud is for you all! There is one storm showing on radar west of Roswell. Probably too far to chase but promising if something could form further east.

c

[anvilhead]

Yeah that cell in NM looks pretty intense. Just gone Severe warned. A 75 mile reposition NW and that might be catchable, but I'd personaly hold fire for something to fire further south and intercept... mind you, im not a forecaster. Still, I can catch better than that guy on camera just now :lol:

[pottyprof]

Looking at the river in the next parking bay.. Id say someone was busting... :lol:

[Marcus_surfer]

That cloud is really annoying, and its chilly out there only 18 Degrees! , however, the cloud is expected to shift according to Wunderground, in Brownfield, Wednesdays temperatures are forecast much hotter, up to 30°C ( 86° F) and 32°C (90° F) by Thursday. This should hopefully produce some great storms for you guys!

[anvilhead]

that cell north of Lubbock is definately growing - 45dbz base now .. just a teaser though

im filling up this thread - someone pm me to shut up please!

[Nick L]

Looking at the river in the next parking bay.. Id say someone was busting...

It's from the air conditioning...I hope :lol:

[anvilhead]

I wonder if thats something going up in extreme SE Cochran county? - looks like things are firing. Gonna be a long night - Anyone for a coffee ?

[Pete the Britt]

How very frustrating, the set up was looking pretty good for today. I feel your pain fella's. Hope you get something to see later tonight, maybe a light show. Keeping fingers crossed nothing goes crazy overnight & clears out tomorrows potential for you. Cam is great to watch, wish i was out there already *sighs*

Pete

[stevestorms]

Yeh need too think a bit about getting the Monkey in front of webcam

[dogs32]

Hi Tammy here - just to update you that we are staying at the hotel at Brownfield where Reed Timmer and Discovery Channel are staying tonight. Its hoped that we will get some pictures of Reed Timmers SRV which we will be able to post later on.

Tammy