072
FXUS64 KLUB 242332
AFDLUB
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LUBBOCK TX
632 PM CDT THU JUN 24 2021
AVIATION
ISOLATED THUNDERSTORMS ACROSS THE WESTERN SOUTH PLAINS HAVE
TEMPORARILY DISSIPATED, BUT MAY ERUPT AGAIN DURING THE EVENING.
STILL, UNLIKELY ANY CELLS WILL APPROACH EITHER KPVW OR KLBB THIS
EVENING. OTHERWISE LOOK FOR CONTINUED VFR WITH A MODEST SURFACE
LOW PRESSURE TROUGH AND MODEST LOW LEVEL FLOW CONTINUING. LOW
LEVEL WIND SHEAR (LLWS) WAS RETAINED FOR THE KCDS TAF LATE TONIGHT
AND EARLY FRIDAY. CHANCE OF THUNDERSTORMS DEVELOPING LATE FRIDAY,
NEARER TO BOTH KPVW AND KLBB BUT AT THE VERY END OF THIS FORECAST
SO NO TAF MENTION YET. RMCQUEEN
PREV DISCUSSION
/ISSUED 249 PM CDT THU JUN 24 2021/
SHORT TERM...
LINE OF SHOWERS HAS DEVELOPED ALONG THE SURFACE TROUGH THIS
AFTERNOON FROM THE WEST CENTRAL TEXAS PANHANDLE DOWN INTO FAR
SOUTHEASTERN NEW MEXICO. CLOUD BASES REMAIN RELATIVELY HIGH WITH
THIS ACTIVITY THEREFORE ONLY SPRINKLES HAVE BEEN REPORTED AS OF 2
PM. TEMPERATURES WILL CONTINUE TO GRADUALLY WARM THROUGH THIS
AFTERNOON AND EVENING WHICH WILL ALLOW INSTABILITY VALUES TO
INCREASE ACROSS THE REGION. WITH THAT SAID BULK SHEAR REMAINS
PITIFUL ACROSS THE REGION SO STORMS WILL REMAIN DISORGANIZED
HOWEVER ANY STRONGER STORM WOULD STILL POSE THE POTENTIAL FOR
STRONG DOWNBURST WINDS. LATE THIS EVENING THUNDERSTORMS WILL COME TO
AN END LEADING TO A QUIET BUT ONCE AGAIN MILD NIGHT ACROSS THE
REGION.
HEIGHTS ALOFT WILL DECREASE JUST SLIGHTLY YET AGAIN TOMORROW AS AN
UPPER LEVEL TROUGH MOVES SOUTH OUT OF THE NORTHERN ROCKIES. THIS
WILL KNOCK AFTERNOON HIGH TEMPERATURES DOWN JUST A DEGREE OR TWO BUT
SHOULD KEEP MOST LOCATIONS BELOW THE CENTURY MARK. SIMILAR TO THE
PAST FEW DAYS A SURFACE TROUGH WILL FORM ACROSS THE WESTERN SOUTH
PLAINS INTO THE WESTERN TEXAS PANHANDLE WHICH WILL ALLOW FOR BREEZY
SOUTHERLY WINDS ONCE AGAIN. BY THE AFTERNOON AND EVENING A WEAK
SHORTWAVE TROUGH WILL ROTATE ACROSS THE NORTHERN TEXAS PANHANDLE
WHICH WHEN COMBINED WITH STRENGTHENING 250 MB FLOW SHOULD PROVIDE
ENOUGH UPPER LEVEL SUPPORT FOR THUNDERSTORM DEVELOPMENT ALONG THE
SURFACE TROUGH. WITH BULK SHEAR VALUES SLIGHTLY STRONGER THAN THE
PAST SEVERAL DAYS, MULTI-CELL CLUSTERS SHOULD DEVELOP ALONG THE
TROUGH AND GENERATE A COLD POOL. AS THE COLD POOL STRENGTHENS
THESE STORMS SHOULD CONGEAL INTO A LINE AND MOVE EAST THROUGH THE
EVENING. WITH MODEST INSTABILITY IN THE 1000-2000 J/KG RANGE
INITIALLY A LOW END SEVERE WIND/HAIL THREAT WILL BE POSSIBLE
ACROSS THE SOUTHWEST AND SOUTHCENTRAL TEXAS PANHANDLE INTO THE
SOUTH PLAINS EVENTUALLY TRANSITIONING TO MAINLY A WIND THREAT
DURING THE EVENING FARTHER EAST. /WCI
LONG TERM...
ISOLATED-TO-WIDELY SCATTERED SHOWERS AND THUNDERSTORMS ARE
EXPECTED TO BE ONGOING ACROSS THE CWA DURING THE EARLY PART OF THE
DAY SATURDAY AS A SOUTHWESTERLY LOW-LEVEL JET NEAR 40 KT ADVECTS
ATOP THE STALLING COLD FRONT. STRONG-TO-INTENSE DIABATIC SURFACE
HEATING IS EXPECTED EVEN IN THE RAIN-COOLED AREAS AS THE BOUNDARY-
LAYER MIXES AND DEEPENS TO AROUND 1-1.5-KM AGL, CHARACTERIZED BY
LOWER 100 MB MEAN MIXING RATIOS OF 13-16 G/KG BENEATH A MODERATE,
TALL EML WITH SB AND MLCAPE VALUES BETWEEN 1,500-2,500 J/KG. ANY
CONVECTIVE OVERTURNING BY OUTFLOW(S) FROM THE PREVIOUS CONVECTION
SHOULD RECOVER BY THIS TIME, WITH THE AFOREMENTIONED RAIN-
COOLED/REINFORCED AREAS OF OUTFLOW IN VICINITY OF THE QUASI-
STATIONARY FRONT SERVING AS A FOCI FOR THUNDERSTORM INITIATION
SATURDAY NIGHT AS A MID-LEVEL SHORTWAVE PERTURBATION EJECTS OVER
THE SOUTHERN/SOUTHWESTERN GREAT PLAINS. MEANWHILE, A RESERVOIR OF
PRECIPITABLE WATER (PWAT) CONTENT NEAR OR POTENTIALLY IN EXCESS OF
THE 99TH PERCENTILE IS FORECAST TO ADVECT ACROSS THE CWA, WITH
PWAT VALUES RANGING FROM 1.20-1.30" ON THE CAPROCK TO UPWARDS OF
1.70" ACROSS THE LOW ROLLING PLAINS.
THE EXCESSIVE PWATS, COMBINED WITH AN INTENSIFYING LOW-LEVEL JET
NEAR 35 KT BENEATH THE AFOREMENTIONED EML, AND A WARM CLOUD-LAYER
EXTENDING TO THE MID-LEVELS (I.E. ~12-13 KFT AGL), WILL RESULT IN
THE POTENTIAL FOR A HEAVY RAIN EVENT AS A MESOSCALE CONVECTIVE
SYSTEM (MCS) IS FORECAST TO DEVELOP SATURDAY NIGHT. RAIN RATES COULD
REACH TO AT LEAST 1-2 INCHES PER HOUR IN THE DEEPEST CORES, THOUGH
LOCALIZED MESOSCALE ENHANCEMENTS MAY RESULT IN HIGHER RAIN RATES PER
HOUR AS WELL, LEADING TO A POTENTIAL FOR FLASH FLOODING WITHIN AREAS
AFFECTED BY THE MCS. INCREASING LOW-LEVEL STORM-RELATIVE WINDS AND A
LARGE INFLUX OF HIGH THETA-E INFLOW LAYER AIR WILL OFFSET THE RATE
OF DIABATIC STABILIZATION DURING THE OVERNIGHT HOURS INTO SUNDAY
MORNING, RESULTING IN AN ENVIRONMENT FAVORABLE FOR MCS MAINTENANCE
AS IT SLOWLY PROPAGATES EASTWARD IN VICINITY OF THE STALLED FRONT.
THE MOVEMENT OF THESE MESO-BETA-ELEMENTS IS EXPECTED TO BE SLOW AS
THE BULK OF THE MORE-AMPLIFIED SYNOPTIC-SCALE FLOW REMAINS DISPLACED
TO THE NORTH AND NORTHEAST, WITH THE POTENTIAL FOR FLASH FLOODING
OUTWEIGHING THE OVERALL RISK FOR SEVERE THUNDERSTORMS. HOWEVER, THE
STANDARD SEVERE HAZARDS OF DAMAGING GUSTS TO 60 MPH AND HAIL TO
AROUND QUARTER SIZE WILL BE POSSIBLE WITHIN THE MCS AS WELL.
ADDITIONAL THUNDERSTORM DEVELOPMENT IS EXPECTED DURING THE DAY
SUNDAY AS WARM ADVECTION CONTINUES AS A SERIES OF WEAKER SHORTWAVE
TROUGHS ROTATE OVERHEAD, THOUGH THE SEVERE THREAT REMAINS LIMITED
GIVEN FAIRLY POOR VERTICAL THERMODYNAMIC PROFILES. EXACT DETAILS
REGARDING POTENTIAL INTENSITY (BOTH FROM A FLOODING AND SEVERE
PERSPECTIVE) ARE NOT YET KNOWN AND WILL BE HIGHLY DEPENDENT ON THE
PREVIOUS NIGHT'S EVENT. RENEWED CHANCES FOR CONVECTION WILL CONTINUE
INTO THE EARLY-MIDDLE PART OF NEXT WEEK AS THE CWA REMAINS UNDER
BROADLY CYCLONIC FLOW WITH THE QUASI-STATIONARY FRONT DRAPED ACROSS
THE I-20 CORRIDOR AND VICINITY.
SINCAVAGE
LUB WATCHES/WARNINGS/ADVISORIES
NONE.
99/99/05
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