Area Forecast Discussion
Issued by NWS Shreveport, LA

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000
FXUS64 KSHV 242359
AFDSHV

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SHREVEPORT LA
659 PM CDT THU APR 24 2014

.AVIATION...
FOR THE 25/00Z TAFS...DRY AIR ALOFT IS QUICKLY MOVING INTO THE
REGION PER LATEST WV LOOPS. THIS IS HELPING TO KEEP ANY REMAINING
CONVECTION N OF THE TAF SITES FOR THE REMAINDER OF THIS EVENING.
SKIES ARE ALSO RAPIDLY CLEARING AS A COLD FRONT MOVES ACROSS THE
TAF SITES. VFR CONDITIONS WILL PREVAIL THROUGH THE ENTIRE TAF
PERIOD. WIND SPEEDS MAY CONTINUE TO GUST NEAR 20 KTS UNTIL THE
PRESSURE GRADIENT RELAXES DURING THE OVERNIGHT HRS. WINDS WILL
SHIFT TO THE NW BEHIND THE FRONT AND THEN GRADUALLY VEER TO THE SE
DURING THE DAYTIME HRS OF FRIDAY. /09/

&&

.PREV DISCUSSION... /ISSUED 624 PM CDT THU APR 24 2014/

DISCUSSION...

UPDATED TO REMOVE SEVEN COUNTIES FROM SEVERE THUNDERSTORMS WATCH
NUMBER 90 THAT INCLUDED 2 FROM NORTHEAST TEXAS...1 IN EXTREME
SOUTHEAST OKLAHOMA AND 4 FROM SOUTHWEST ARKANSAS. LOWERED THE RAIN
CHANCES FOR SOME OF THE AFFECTED COUNTIES AND MADE ADJUSTMENT TO
OTHER ELEMENTS IN THE GRIDDED DATA. /06

PREV DISCUSSION... /ISSUED 425 PM CDT THU APR 24 2014/

DISCUSSION...
SCT CONVECTION CONTINUES TO FIRE THIS AFTERNOON ACROSS NCNTRL
LA/SCNTRL AR...ALONG A NE TO SW ORIENTED 850MB THETA-E AXIS ALONG
THE LEADING EDGE OF THE UPPER TROUGH WHICH HAS TAKEN A NEGATIVE
TILT OVER ERN OK. DRY AIR HAS BEGUN TO ENTRAIN NE BENEATH THE
TROUGH ACROSS SE OK/SW RA/E TX/NW LA...WITH THE BEST FORCING
MAINLY NEAR THE TROUGH AXIS OVER SE OK/SW AR...AND FARTHER E WHERE
BETTER DIFFLUENCE EXISTS WITHIN THE MOIST SECTOR OVER NCNTRL LA.
THE SVR THREAT SHOULD BE SHORT LIVED THROUGH EARLY EVENING AS THE
AIR MASS STABILIZES WITH THE LOSS OF DIURNAL HEATING...AND THE
FORCING AHEAD OF THE TROUGH QUICKLY SHUNTS E OF THE AREA INTO THE
MID-SOUTH REGION. THE COLD FRONT ITSELF EXTENDS FARTHER W FROM
NEAR FSM...TO NEAR PRX...TO TRL/CRS...JUST JUST NW OF ATT AS OF
21Z...WITH IT EXPECTED TO QUICKLY SPILL SE INTO SW AR/EXTREME ERN
TX BY 00Z...AND EXITING THE SRN/ERN SECTIONS OF NCNTRL LA AFTER
06Z. CONVERGENCE IS WEAK ALONG THE FRONT ITSELF AS WINDS ARE
VEERING SW AHEAD OF IT...WITH DEEPER DRY AIR ENTRAINMENT INHIBITING
ADDITIONAL CONVECTION DEVELOPMENT FARTHER S AWAY FROM THE TROUGH.
DID MAINTAIN LOW CHANCE POPS THIS EVENING FOR SCNTRL AR/ERN
SECTIONS OF NCNTRL LA...TAPERING TO SLIGHT CHANCE ELSEWHERE TO
RESPECT THE FRONT ITSELF...DROPPING POPS AFTER 06Z WITH THE FROPA
EXCEPT FOR THE SE ZONES. DRIER AIR SHOULD ADVECT SE AHEAD OF A
BUILDING SFC RIDGE LATE TONIGHT/FRIDAY MORNING...RESULTING IN A
COUPLE OF PLEASANT MORNINGS AND LOWER RH/S THE NEXT COUPLE OF
DAYS. WINDS HAVE ALSO DROPPED OFF WITH THE INCREASED CLOUD COVER
AHEAD OF THE FRONT...AND HAVE CANCELLED THE LAKE WIND ADVISORY.

TEMPS SHOULD REMAIN NEAR/SLIGHTLY ABOVE CLIMO THE NEXT COUPLE OF
DAYS...WITH A LIGHT SERLY LOW LEVEL FLOW EXPECTED TO RETURN BY
FRIDAY EVENING AS THE SFC RIDGE SHIFTS E OF THE AREA. WILL NOT SEE
A MORE PRONOUNCED RETURN IN RH/S UNTIL SATURDAY THOUGH AS THE
PRESSURE GRADIENT TIGHTENS OVER THE SRN PLAINS IN RESPONSE TO THE
NEXT UPPER TROUGH AS IT DIGS INTO THE DESERT SW. THIS TROUGH IS
PROGGED TO CLOSE OFF AS IT ENTERS THE PLAINS SUNDAY...TAKING ON A
STRONG NEGATIVE TILT AND THUS...ALLOWING THE W TX DRY LINE TO MIX
E INTO ERN OK/NEAR THE I-35 CORRIDOR OF CNTRL TX SUNDAY AFTERNOON.
SCT CONVECTION IS EXPECTED TO QUICKLY FIRE ALONG/JUST AHEAD OF THE
DRY LINE...AND QUICKLY SPREAD ENE INTO NE TX/SE OK/SW AR BY EARLY
AFTERNOON...AS MODERATE TO STRONG INSTABILITY DEVELOPS WITHIN THE
BROAD WARM SECTOR. STRONG DEEP LAYER SHEAR AND VERY STEEP LAPSE
RATES BEHIND THE DRY LINE WILL CONTRIBUTE IN CONVECTION BECOMING
SVR AND QUICKLY SPREADING OVER MUCH OF THE REGION SUNDAY
AFTERNOON...EVENTUALLY AFFECTING N LA/SRN AR DURING THE LATE
AFTERNOON/EVENING. HAVE INCREASED POPS TO LIKELY/HIGH CHANCE FOR
MUCH OF THE AREA...WITH THIS SVR OUTBREAK EXPECTED TO DIMINISH
OVER THE ERN ZONES LATE. THIS PROBABLE MCS SHOULD LEAVE BEHIND A
SFC BNDRY WHICH THE GFS/ECMWF STALL OVER SRN AR/NW LA/E TX...AND
FOCUS ANOTHER ROUND OF POTENTIAL SVR CONVECTION MONDAY AFTERNOON
MAINLY OVER THE ERN ZONES. HEAVY RAINFALL/TRAINING WILL BE A
CONCERN HERE AS THE FLOW BECOME UNIDIRECTIONAL...AS LARGE SCALE
FORCING INCREASES IN ADVANCE OF THE NEXT SHORTWAVE ROUNDING THE
CLOSED LOW AS IT BECOMES CUT OFF OVER THE MIDWEST/MID MS VALLEY.

HAVE INCREASED POPS TO HIGH CHANCE E OF THE SFC BNDRY...WITH THIS
CONVECTION EXPECTED TO DIMINISH DURING THE EVENING AS IT BNDRY IS
NUDGED E OF THE AREA. THE ATTENDANT COLD FRONT ITSELF WILL NOT
ENTER THE REGION UNTIL TUESDAY AFTERNOON/EVENING...BEFORE MUCH
COOLER AND DRIER AIR SPILLS S INTO THE AREA THROUGH THE MID AND
LATE WEEK TIMEFRAME. THE PATTERN RESEMBLES A SIMILAR SETUP /ALBEIT
THE CLOSED LOW WAS ATOP OUR REGION THE FIRST WEEK OF MAY LAST
YEAR/...AND COULD VERY WELL SIGNAL THE LAST OF THE COOL SPELLS
BEFORE HOTTER/MORE HUMID CONDITIONS TAKE OVER FOR THE SUMMER. DID
NOT MAKE MANY CHANGES TO THE GOING TEMPS...AS TEMPS FALL 10-15
DEGREES BELOW NORMAL.

PRELIMS TO FOLLOW BELOW...

15

PREV DISCUSSION... /ISSUED 1230 PM CDT THU APR 24 2014/

AVIATION...
COLD FRONT ON APPROACH THIS CYCLE WITH NW WINDS BY 18Z INTO KMLC
AND KDFW. ARKLATEX SFC WINDS ARE S/SW 10-20KTS WITH A FEW HIGHER
GUSTS. OUR CLIMB WINDS ARE GENERALLY SW 20-40KTS. WE ARE VFR
NOW...BUT MVFR CIGS OVER NE TX IN THE WAKE OF MORNING SHORT WAVE
IN W AR. ANOTHER SHORT WAVE IMPULSE IS RIPING OVER THE RIO GRANDE
NOW AND MAY ENHANCE LIFT WITH HEATING OVER OUR AREA AHEAD OF THE
FRONT. SCT TSTMS EXPECTED FROM W TO 21Z-25/06Z. POST FRONTAL WINDS
NW 5-15KTS WITH GOOD DRYING SO. LITTLE IF ANY LOW CLOUDS OR BR
EARLY WITH FEW TO SCT FAIR WEATHER CU FOR FRIDAY. /24/

&&

.PRELIMINARY POINT TEMPS/POPS...
SHV  56  83  56  85  67 /  20   0   0  10  10
MLU  57  81  54  86  65 /  30   0   0  10  10
DEQ  48  82  49  83  66 /  20   0   0  10  20
TXK  54  81  54  84  66 /  20   0   0  10  20
ELD  54  81  51  85  65 /  30   0   0  10  10
TYR  55  84  59  85  67 /  10   0   0  10  20
GGG  55  83  56  85  67 /  10   0   0  10  20
LFK  58  83  60  85  68 /  20   0   0  10  10

&&

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

$$

06/09





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