563
FXUS64 KSHV 251141
AFDSHV
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SHREVEPORT LA
641 AM CDT MON OCT 25 2021
AVIATION
A COLD FRONT CONTINUES TO MAKE STEADY SWD PROGRESS THIS MORNING.
AHEAD OF THE FRONT'S ARRIVAL, MVFR/IFR CIGS/VSBYS ARE BEING
OBSERVED, AND THESE WILL CONTINUE UNTIL THE COLD FRONT REACHES THE
RESPECTIVE TERMINALS THROUGH LATE THIS MORNING. VFR CONDITIONS TO
LAST THROUGH THE END OF THE PD, AS WINDS BECOME NWLY AT GENERALLY
LESS THAN 10 KTS. WINDS WILL VEER AROUND TO THE NE AFTER SUNSET. /12/
PREV DISCUSSION
/ISSUED 342 AM CDT MON OCT 25 2021/
SHORT TERM.../TODAY THROUGH TUESDAY/
WEAK AND SLOWING COLD FRONT DRAPED ACROSS OUR NWRN AREAS THIS
MORNING, AS THE PARENT SHORTWAVE MOVES EWD INTO IL. FLOW ALOFT IS
ALREADY NWLY IN THE WAKE OF THE TROF AXIS. FRONT TO CONTINUE SEWD
TODAY, BRINGING A SLIGHTLY MODIFIED AIRMASS SWD. IT WILL NOT,
HOWEVER, MAKE MUCH DIFFERENCE FOR TODAY, SAVE FOR THE NRN THIRD OF
OUR AREA. THE REMAINDER OF THE REGION WILL LIKELY SEE TEMPS
SOARING AGAIN TOWARDS 90 DEGREES.
FRONT TO STALL THIS AFTN AND BECOME ORIENTED NW TO SE FROM TYLER
TX TO COLFAX LA, ALLOWING FOR THE COOLER/DRIER AIRMASS TO SINK SWD
ACROSS OUR NERN AREAS. THIS WILL CREATE QUITE A DISPARITY IN TEMPS
FROM THE VERY WARM SW TO THE MUCH COOLER NE ACROSS OUR REGION
OVERNIGHT.
UPPER RIDGE AXIS TO DRIFT OVHD TONIGHT INTO TUESDAY WHILE SLY
WINDS RETURN ACROSS THE WRN HALF OF THE REGION. THIS WILL CAUSE
THE STALLED BOUNDARY TO RETREAT FURTHER ON THE WRN FLANK, KEEPING
THE 10 DEGREE OR SO TEMPERATURE DISPARITY ONGOING. SWLY FLOW ALOFT
TO RESUME BY TUESDAY AFTN, AS THE RIDGE AXIS DEPARTS TO THE E
AHEAD OF OUR NEXT STORM SYSTEM. /12/
LONG TERM.../TUESDAY NIGHT THROUGH SUNDAY NIGHT/
BOTTOM LINE UP FRONT: WHILE TIMING IS STILL UNCERTAIN, AN "ALL
MODES" SEVERE WEATHER EVENT APPEARS TO BE COMING TOGETHER FOR
WEDNESDAY. GIVEN IMPRESSIVE BULK-SHEAR VALUES AND TROUGH
ORIENTATION, DAMAGING WINDS AND QLCS TORNADOES APPEAR TO BE THE
GREATEST THREATS.
BEHIND THE FRONT IN THE SHORT-TERM, WARM AIR ADVECTION WILL HELP
KEEP TEMPERATURES WELL ABOVE AVERAGE FOR THIS TIME OF THE YEAR.
THESE ABOVE AVERAGE TEMPERATURES WILL NOT LAST LONG, AS THE
PREVIOUSLY MENTIONED MASSIVE TROUGH BEGINS TO EJECT OFF THE ROCKY
MOUNTAINS. THIS LOW PRESSURE WILL DIG ACROSS W. TEXAS, WHERE IT
LOOKS TO BECOME DECOUPLED FROM THE UPPER-LEVEL PATTERN, CLOSING
ITSELF OFF. IT'S WORTH NOTING THAT MANY RECENT GUIDANCE RUNS HAVE
THIS LOW PRESSURE REMAINING OPEN DURING ITS EJECTION COURSE. WHILE
THE CLOSED LOW PREVIOUSLY LOOKED TO BE POTENT AS-IS, AN OPEN WAVE
WOULD ONLY MAKE AN IMPRESSIVE KINEMATIC REGIME THAT MUCH MORE
POTENT. AGAIN, BASED ON WHAT I HAVE AT MY DISPOSAL THIS MORNING, IT
CONTINUES TO LOOK LIKE INSTABILITY RETURN WILL BE AN ISSUE. THERE IS
QUITE THE SPREAD ON FORECAST VALUES, RANGING FROM 200 J/KG TO 2000
J/KG, WITH THE GFS CURRENTLY BEING THE MOST AGGRESSIVE. AS SUCH,
THIS EVENT IS STILL SHAPING UP TO BE A "HIGH SHEAR, LOW CAPE" TYPE
OF SITUATION. THE LOWER INSTABILITY SCENARIOS STILL INVOLVE MORNING
CONVECTION AND CLOUD COVER KEEPING THE SUNLIGHT AT BAY FOR THE
AFTERNOON REBOUND.
CONTINUING WITH MY LINE OF THINKING YESTERDAY, THE MOST LIKELY
SCENARIO APPEARS TO BE A LINE OF STORMS DEVELOPING TO THE WEST OF
DFW BY 7AM ON WEDNESDAY AND MOVING EAST. THIS LINE OF STORMS WOULD
START EFFECTING OUR WESTERN ZONES BY THE EARLY AFTERNOON HOURS.
GIVEN THE IMPRESSIVE AMOUNTS OF BULK-SHEAR, DAMAGING WINDS WOULD BE
POSSIBLE WITH THESE STORMS. HOWEVER, THE ORIENTATION OF THE SHEAR
VECTORS STILL REMAIN INDICATIVE OF A QLCS TORNADO THREAT. BOTH 0-1KM
AND 0-3KM SHEAR VECTORS PARALLEL THE LINE OF STORMS NEAR A 45 DEGREE
ANGLE. A FAVORABLE PLACEMENT FOR QLCS TORNADOES. HOWEVER, IT ONCE
AGAIN BARES MENTIONING THAT THIS EVENT IS STILL IN THE D3 TIMEFRAME,
AND IS VERY MUCH STILL SUBJECT TO CHANGE AS GUIDANCE AGREEMENT COMES
INTO PLACE.
BEHIND THE COLD FRONT ON THURSDAY, LOOK FOR MUCH COOLER TEMPERATURES
FOR THE REST OF THE WORKWEEK, AND INTO THE WEEKEND. ADDITIONALLY,
THE CHANCE FOR SOME WRAP AROUND PRECIPITATION LOOKS POSSIBLE INTO
FRIDAY, AND THE LOW CONTINUES TO MOVE EAST. GUSTY WINDS LOOK LIKELY
INTO THE WEEKEND AS WELL, AS THE PRESSURE GRADIENT SHOULD REMAIN
TIGHT FOR SOME TIME AFTER FROPA.
/44/
PRELIMINARY POINT TEMPS/POPS
SHV 87 60 84 69 / 10 0 0 30
MLU 86 54 79 63 / 10 0 0 10
DEQ 81 52 78 63 / 0 0 0 40
TXK 83 56 81 68 / 0 0 0 30
ELD 81 51 77 62 / 0 0 0 10
TYR 88 65 88 69 / 0 0 0 50
GGG 88 61 86 69 / 10 0 0 40
LFK 91 67 89 70 / 0 0 0 30
SHV WATCHES/WARNINGS/ADVISORIES
AR...NONE.
LA...NONE.
OK...NONE.
TX...NONE.
12/44
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page