Area Forecast Discussion
Issued by NWS Shreveport, LA

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FXUS64 KSHV 250505
AFDSHV

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SHREVEPORT LA
1205 AM CDT FRI APR 25 2014

.AVIATION...
FOR THE 25/06Z TAFS...VFR CONDITIONS SHOULD PREVAIL AT ALL TAF
SITES THROUGH THE ENTIRE PERIOD. A BROKEN LINE OF SHWRS HAS
DEVELOPED AHEAD OF THE COLD FRONT...WHICH HAS CLEARED ALL TAF SITES
EXCEPT KLFK AND KMLU AS OF 25/05Z. IMPACTS FROM PRECIP SHOULD ONLY
BE FOR THE FIRST COUPLE OF HRS OF THE PERIOD. OTHERWISE...SOME
HIGH CIRRUS SHOULD AFFECT SITES NORTH OF I-20 TONIGHT BEFORE
SPREADING AREAWIDE DURING THE DAY FRIDAY. WINDS WILL REMAIN BELOW
10 KTS AND GRADUALLY VEER FROM THE NW BEHIND THE COLD FRONT TO
SELY BY FRIDAY AFTERNOON AS A SFC HIGH MOVES NE OF THE REGION. /09/

&&

.PREV DISCUSSION... /ISSUED 1025 PM CDT THU APR 24 2014/

DISCUSSION...

UPDATED TO CANCEL REMAINING COUNTIES/PARISHES IN COUNTY WARNING
AREA UNDER SEVERE THUNDERSTORMS WATCH 90. A SMALL BROKEN BAND OF SHOWERS
EXTENDED ALONG AND NEAR THE FRONTAL BOUNDARY MOVING ACROSS
S CENTRAL AND SE AR AND N CENTRAL AND NW LA...AND E AND NE TX
ROM NEAR EL DORADO AR...TO MINDEN AND STONEWALL LA AND JACKSONVILLE
TX. FINAL ADJUSTMENTS TO THE WINDS...DEW POINTS...AND RAIN
CHANCES FOR TONIGHT. SKIES WILL GRADUALLY CLEAR FROM THE WEST OVERNIGHT.
/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. /15/

&&

.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 /  10   0   0  10  20
TXK  54  81  54  84  66 /  10   0   0  10  20
ELD  54  81  51  85  65 /  20   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 /  30   0   0  10  10

&&

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

$$

06/09




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