Area Forecast Discussion
Issued by NWS Shreveport, LA

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary Off
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50

000
FXUS64 KSHV 281032
AFDSHV

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SHREVEPORT LA
532 AM CDT THU MAY 28 2015

.DISCUSSION...
ALL IS QUIET FOR THE TIME BEING...ALTHOUGH CONFIDENCE REMAINS
SOMEWHAT LOW IN THE SHORT TERM FORECAST...AND WILL BE DETERMINED
BY TWO FACTORS. THE FIRST BEING THE UPSTREAM MCS APPROACHING THE
MIDDLE RED RIVER VALLEY OF SRN OK/N TX...AND THE SECOND BEING A
WEAK AREA OF MID LEVEL CONVERGENCE THAT WILL SPREAD ENE INTO NE
TX/SW AR/N LA THIS AFTERNOON ALONG WEAK DIRTY RIDGING THAT WILL
TRY AND BUILD NE INTO THE MID-SOUTH REGION INTO THE TN VALLEY.
HOWEVER...ALL BETS WILL BE OFF ON THE LATTER SHOULD THIS MCS
MAINTAIN ITS MOMENTUM AND MOVE INTO THE REGION BY LATE
MORNING/EARLY AFTERNOON. THE 09Z SFC ANALYSIS DOES DEPICT A
DISTINCT SFC THETA-E BNDRY ALONG/JUST S OF THE RED RIVER BEFORE
ARCING SE INTO WRN LA...THUS FOCUSING AN AXIS OF INSTABILITY
WHEREAS MORNING MLCAPES RANGE FROM 1000-1500 J/KG TO THE W OF THIS
BNDRY. THE HRRR DOES INITIALIZE ON THE MCS /ALBEIT 1-2 HOURS
SLOWER/ AND BUILDS IT ESE AND GUSTING OUT AS IT MOVES INTO EXTREME
SE OK/NE TX BETWEEN 15-17Z. GRANTED...IT WILL BE OUTRUNNING THE
SHORTWAVE ENERGY NOW OVER CNTRL NM...BUT THE REMNANTS OF THIS
SYSTEM SHOULD FOCUS SCT CONVECTION OVER AT LEAST THE NRN HALF OF
THE REGION...WHICH MAY INTERACT OF THE WEAK MID LEVEL CONVERGENCE
THAT SHOULD SHIFT E INTO SCNTRL AR/NCNTRL LA THIS AFTERNOON. HAVE
CONCENTRATED BEST POPS OVER EXTREME NE TX/SE OK/SW AR...WITH LOW
CHANCE POPS FARTHER SE OVER NCNTRL LA. DESPITE THE WEAK SHEAR IN
PLACE...CAN/T RULE OUT ISOLATED SVR THIS AFTERNOON AND MODERATE
MLCAPES DEVELOP THIS AFTERNOON WITH HEATING. THE PRESENCE OF THE
WEAK RIDGING ALOFT W OF THE MID LEVEL CONVERGENT AXIS SHOULD HELP
KEEP THE CONVECTION MORE ISOLATED TODAY OVER THE SW SECTIONS OF E
TX.

THE UPPER LEVEL PATTERN WILL QUICKLY CHANGE FRIDAY THROUGH EARLY
NEXT WEEK AS A SHORTWAVE DROPPED SE ACROSS THE NRN GREAT BASIN
BENEATH AN OPENING TROUGH OVER ERN ID...SHIFTS E ALONG THE RED
RIVER VALLEY TONIGHT...THIS IGNITING SCT/NUMEROUS CONVECTION FROM
WCNTRL TX N INTO WRN OK...WITH PERHAPS ANOTHER MCS DEVELOPING AND
SPREADING ESE ACROSS SRN OK/NCNTRL TX. THIS CONVECTION SHOULD
AFFECT NE TX/SE OK/SW AR FRIDAY MORNING...WITH POTENTIAL MESOSCALE
BNDRYS FOCUSING ADDITIONAL SCT CONVECTION FARTHER E AHEAD OF THE
N-S UPPER TROUGH AS IT SETTLES INTO CNTRL OK/TX. HAVE INCREASED
POPS TO LIKELY FOR THE NW THIRD OF THE AREA...WITH HIGH CHANCE
POPS ELSEWHERE...ALTHOUGH MUCH OF THIS CONVECTION MAY BE TIED TO
HEATING AND TEND TO DIMINISH FRIDAY NIGHT. WHILE UPSTREAM WFO/S
HAVE ISSUED FLASH FLOOD WATCHES THIS MORNING FOR TONIGHT/THIS
WEEKEND...CONFIDENCE STILL REMAINS TOO LOW AT THIS POINT IN
REGARDS TO CONVECTION EVOLUTION/COVERAGE AS WELL AS QPF AMOUNTS TO
WARRANT THE ISSUANCE OF A WATCH FOR PORTIONS OF THE REGION ATTM.
HOWEVER...LATER SHIFTS WILL RE-EVALUATE LATER TRENDS/SUBSEQUENT
MODEL RUNS FOR THE NEED FOR ONE LATER TODAY/FRIDAY GIVEN THE STILL
SATURATED GROUNDS. THE AFOREMENTIONED UPPER TROUGH LOOKS TO
BECOME STATIONARY OVER THE REGION THIS WEEKEND BEFORE NOSING
SLOWLY E AND BECOMING ABSORBED IN A SECONDARY TROUGH NOW OVER ERN
ID.

SHOULD SEE PERIODS OF SCT/NUMEROUS CONVECTION DEVELOP THIS
WEEKEND AREAWIDE...AND BECOME PRIMARILY MESOSCALE DRIVEN AS SHEAR
WEAKENS FURTHER BENEATH THE WEAK TROUGH AXIS. HAVE ADDED LIKELY
POPS FOR AREAS ALONG/N OF I-20 SATURDAY...WITH THE PROGS DEPICTING
A WEAK SFC FRONT DRIFTING SE INTO SE OK/EXTREME NE TX/SW AR
SATURDAY NIGHT. THE ECMWF IS A BIT SLOWER WITH THE PROGRESSION OF
THE BNDRY AND IS PREFERRED FOR THIS FORECAST PACKAGE BEFORE
BECOMING STATIONARY SOMEWHERE OVER E TX/N LA BY LATE SUNDAY. DID
KEEP MID TO HIGH CHANCE POPS ALONG/AHEAD OF THIS BNDRY THIS
WEEKEND...TAPERING RAIN CHANCES OFF FROM THE NW BY SUNDAY AS DRIER
AIR ALOFT BEGINS TO ENTRAIN SE BEHIND THE EWD DRIFTING TROUGH
AXIS. BOTH THE GFS/ECMWF CONTINUE TO CLOSE THE TROUGH OFF BY
MONDAY...ALTHOUGH DISCREPANCIES ARISE THEREAFTER...WITH THE GFS
FARTHER W WITH THE CLOSED LOW BECOMING STATIONARY SOMEWHERE
NEAR/JUST W OF THE LOWER MS VALLEY. AGAIN PREFER THE ECMWF
HANDLING OF THE CLOSED LOW...AS IT HAS BEEN PERSISTENT IN RUNS THE
LAST FEW DAYS REMAINING NEAR THE MS RIVER. HOWEVER...GIVEN ITS
PROXIMITY EVEN ON THE NORMALLY SUBSIDENT SIDE...CAN/T REMOVE POPS
FROM THE FORECAST FOR MUCH OF NEXT WEEK AS MAINLY
AFTERNOON/EVENING ISOLATED TO WIDELY SCT CONVECTION SHOULD DEVELOP
EACH DAY...ESPECIALLY OVER SW AR/N LA. ASIDE FROM
CONVECTION/ABUNDANT CLOUD COVER EXPECTED TO KEEP TEMPS SLIGHTLY
BELOW NORMAL THIS WEEKEND...LOOK FOR TEMPS TO RETURN BACK TO
NEAR CLIMO FOR MUCH OF NEXT WEEK AS WE MOVE INTO THE FIRST WEEK OF
JUNE.

PRELIMS TO FOLLOW BELOW...

15

&&

.PRELIMINARY POINT TEMPS/POPS...
SHV  88  72  86  69 /  30  20  50  40
MLU  88  70  88  69 /  30  20  40  30
DEQ  84  68  82  67 /  50  30  60  50
TXK  86  70  84  68 /  40  30  60  50
ELD  86  69  86  69 /  30  20  50  40
TYR  88  72  84  69 /  20  30  50  40
GGG  88  72  84  69 /  20  20  50  40
LFK  90  73  87  71 /  20  20  50  30

&&

.SHV WATCHES/WARNINGS/ADVISORIES...
AR...NONE.
LA...NONE.
OK...NONE.
TX...NONE.
&&

$$

15


USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.