CONVECTIVE OUTLOOK...
THERE IS A SLGT RISK OF SVR TSTMS TO THE RIGHT OF A LINE FROM
25 ENE RAP 35 SW Y22 15 N Y22 25 SW BIS 45 ESE BIS 35 W ABR
30 WSW 9V9 20 SSW VTN 40 ESE CDR 40 SE RAP 25 ENE RAP.
THERE IS A SLGT RISK OF SVR TSTMS TO THE RIGHT OF A LINE FROM
35 ESE BGS 60 NNW CDS 40 SE LBL 45 WSW HLC 45 NNE HLC 20 SSE HSI
35 SE BIE 25 ESE TOP 40 ENE CNU 20 WSW FYV 40 ESE PRX 55 SSW TYR
25 SSE CLL 50 SSE AUS 50 SSW JCT 55 NNW DRT 35 ESE BGS.
GEN TSTMS ARE FCST TO THE RIGHT OF A LINE FROM 35 E INL 10 ESE EAU
30 WNW PIA 20 E JBR 30 SW UOX 35 WNW MEI 10 N LUL 30 WNW GPT
15 S MSY 25 SSW 7R4 ...CONT... 10 ENE GLS 45 WNW VCT 30 N COT
20 WNW COT 25 NW LRD ...CONT... 35 WNW DRT 30 W CDS 60 WSW GAG
15 NW LBL 35 ESE 4LJ 35 SE LHX 45 NW CAO 50 SSE RTN 20 SW LVS
20 E GUP 55 E PGA 20 WNW DPG 35 NNW TWF 50 SW 27U 50 NW 27U
25 SE 3TH 100 NE 63S.
--- SYNOPSIS ---
ROCKIES LONGWAVE TROUGH WILL AMPLIFY AS TROUGH NOW OVER SD EJECTS
NEWD...AND SHORTWAVE TROUGH EVIDENT ON MOISTURE CHANNEL IMAGERY
OVER WRN AZ MOVES E. MIDDLE-UPPER LEVEL WINDS ACROSS SWRN CONUS ON
BOTH SIDES OF THIS FEATURE WERE SIGNIFICANTLY UNDERFORECAST BY
00Z/03Z ETA...BASED ON LATEST RAOB DATA AND OBSERVATIONS FROM
REGIONAL VWP/ACARS. AVN WINDS/HEIGHTS ARE VERIFYING MUCH BETTER
THIS MORNING...AND SUGGEST MID/UPPER LEVEL FLOW MAY BE STRONGER
THAN FORECAST BY ETA OVER SRN PLAINS THIS EVENING. TROUGH SHOULD
REMAIN PROGRESSIVE BUT COULD BE SLIGHTLY MORE AMPLIFIED THAN
PROGGED AS IT MOVES ACROSS NERN AZ AND NM...REACHING TX PANHANDLE
THIS EVENING. SURFACE LOW N GCC SHOULD MOVE EWD ACROSS SD...WHILE
LEE TROUGH FARTHER S OVER SRN HIGH PLAINS STRENGTHENS THIS EVENING.
... SEVERE THUNDERSTORM FORECAST DISCUSSION ...
--- CENTRAL/SOUTHERN PLAINS ---
EXPECT GREATEST CONVECTIVE THREAT AFTER ABOUT 23Z...WHEN LARGE-
SCALE ASCENT ASSOCIATED WITH AZ SHORTWAVE TROUGH BEGINS TO IMPINGE
UPON DRYLINE REGION. SUBSIDENCE ASSOCIATED WITH FOREGOING
SHORTWAVE RIDGE SHOULD HELP TO REMOVE BOTH CLOUD COVER AND
CONVECTIVE THREAT IN THE MEANTIME...WHILE AIDING DIABATIC SURFACE
HEATING. ETA DESTABILIZATION N OF RED RIVER THRU EARLY
AFTERNOON...HOWEVER...IS OVERDONE BECAUSE OF HIGH DEW POINT
FORECASTS. LARGEST BUOYANCY SHOULD BE OVER N-CENTRAL/NWRN TX WHERE
MID/UPPER 60S DEW POINTS AND TEMPS MID 80S F WILL CONTRIBUTE TO
MLCAPE APPROACHING 3000 J/KG...SBCAPE TO 4500 J/KG. ZONE OF UPPER
LEVEL DIVERGENCE/ UVV IN ETA...ASSOCIATED WITH LEFT EXIT REGION OF
CYCLONICALLY CURVED SUBTROPICAL SPEED MAX OVER MEX/S TX...SHOULD
REMAIN BROAD AND WEAK -- NOT WITH SUDDEN INTENSIFYING EVIDENTLY
ASSOCIATED WITH ETA CONVECTIVE FEEDBACK.
UPPER LEVEL FLOW IS EXPECTED TO BACK DURING LATE AFTERNOON AND
EVENING AS AZ SHORTWAVE TROUGH APPROACHES. THIS SHOULD HELP TO
TREND STORM EVOLUTION TOWARD HP THEN LINEAR VIA TWO PRIMARY EFFECTS
AT ANVIL LEVEL. THOUGH SR FLOW WILL NOT BE AS WEAK AS ETA
PROGS...IT STILL SHOULD BE GENERALLY AOB 40 KT WITH PRECIP PARTICLE
RECYCLING...AND FLOW DIRECTION SUGGESTS SEEDING FROM MERIDIONAL
COALESCENCE OF ANVILS UP AND DOWN CONVECTIVE ZONE. BRIEF WINDOW OF
TORNADO POTENTIAL MAY EXIST WITH A FEW STORMS BETWEEN ABOUT AN HOUR
AFTER INITIATION...AND FULLY OUTFLOW-DOMINANT HP TRANSITION.
HOWEVER...MAIN THREAT SHOULD BE LARGE HAIL FIRST FEW HOURS AFTER
INITIATION...TRANSITIONING TO DAMAGING WIND.
LINE OF STRONG-SEVERE THUNDERSTORMS IS EXPECTED TO FORM FROM
AFTERNOON/EARLY EVENING DEVELOPMENT...THEN MOVE EWD ACROSS MUCH OF
CENTRAL/ERN KS...CENTRAL/ERN OK AND N-CENTRAL TX AFTER 6Z. EXPECT
SOME LEWPS/BOWS WITH DAMAGING WIND...AND A MARGINAL THREAT OF
EMBEDDED TORNADOES. SRN END OF BACKBUILDING LINE SOMEWHERE OVER
CENTRAL TX WILL BE DICTATED BY CAPPING AT BASE OF ELEVATED MIXED
LAYER ADVECTED OFF HIGH MEX PLATEAU...WHICH IS ALREADY EVIDENT
ABOVE 750 MB IN 12Z DRT SOUNDING.
--- N-CENTRAL PLAINS ---
FOR MOST OF TODAY...SHORTWAVE RIDGING BEHIND CURRENT EJECTING SD
SHORTWAVE TROUGH WILL SUPPRESS CONVECTION AND AID IN INSOLATION.
BY MID/LATE AFTERNOON...ISALLOBARIC FORCING INVOF LOW LEVEL CYCLONE
WILL RESULT IN BACKED BOUNDARY LAYER FLOW AND ENHANCED
CONVERGENCE/LIFT ON MESO ALPHA SCALE. ETA PFC SOUNDINGS SHOW SMALL
HODOGRAPHS WITH SRH AOB 100 J/KG...BUT REGIONAL ISALLOBARIC FORCING
SHOULD STRENGTHEN NEAR-SURFACE FLOW MORE THAN PROGGED...INCREASING
SR LOW LEVEL INFLOW.
EXPECT MLCAPE NEAR 1000 J/KG...SUPPORTING DEVELOPMENT OF WIDELY
SCATTERED STRONG-SEVERE THUNDERSTORMS NEAR LOW AND ATTACHED SURFACE
TROUGHS AND DRYLINE. A FEW STORMS SHOULD ROTATE...BUT WEAKNESSES
IN LOW-MID LEVEL SR FLOW ABOVE THAT SUGGEST MAIN THREAT WILL BE
LARGE HAIL...WITH ISOLATED DAMAGING WIND POSSIBLE. INSOLATION IS
SUCH A MAJOR CONTRIBUTOR TO CAPE IN MODIFIED FORECAST SOUNDINGS
THAT THREAT SHOULD DECREASE GREATLY AFTER DARK.
..EDWARDS..
