National Weather Service Weather Forecast Office

• Home
• Site Map
• News
• Organization
• Search for: NWS All NOAA 

000
FXUS64 KSHV 190942
AFDSHV

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SHREVEPORT LA
442 AM CDT SUN MAY 19 2013

.DISCUSSION...
THE MORNING LOW STRATUS HAS JUST BEGUN TO SPREAD N INTO E TX/N LA
EARLY THIS MORNING...AND SHOULD ADVECT N ACROSS THE REMAINDER OF THE
AREA THROUGH SUNRISE...SCATTERING OUT BY MID TO LATE MORNING. THE
PRESSURE GRADIENT WILL BEGIN TO TIGHTEN UP BY MID-MORNING ACROSS THE
SRN PLAINS...AHEAD OF A 998MB SFC LOW THAT WILL DRIFT E OVER SRN KS/NW
OK ALONG THE DRY LINE ONCE IT MIXES E INTO WCNTRL OK/NW TX THIS
AFTERNOON. LAKE WIND ADVISORY CRITERIA SHOULD BE MET ACROSS ALL OF E
TX/SE OK...HOWEVER HAVE EXPANDED THE CURRENT ADVISORY E INTO PORTIONS
OF EXTREME SW AR AND WRN LA AS WIND GUSTS TO 25-30 MPH WILL BE
POSSIBLE. OTHERWISE...PERSISTENCE IN TEMPS WILL BE THE RULE TODAY ONCE
THE LOW STRATUS SCATTERS OUT...WITH MAX TEMPS NEARING OR EXCEEDING 90
DEGREES AREAWIDE. THE SHORT TERM PROGS REMAIN CONSISTENT WITH THE ROCKIES
UPPER TROUGH DRIFTING E AND CLOSING OFF OVER WRN NE/SD TODAY...WITH A
MID LEVEL SHORTWAVE/SPEED MAX ROUNDING THE TROUGH ACROSS CNTRL OK INTO
ERN KS THIS AFTERNOON AND EVENING. STRONG DIURNAL HEATING AND
RESULTANT MLCAPES EXCEEDING 3000-3500 J/KG WITHIN IN STRONGLY SHEARED
ENVIRONMENT WILL RESULT IN SCT STRONG/SVR CONVECTION DEVELOPING ONCE
AGAIN THIS AFTERNOON IN VC OF THE DRYLINE...WHICH SHOULD ADVANCE ENE
ACROSS NW TX/OK/CNTRL PLAINS LATE THIS AFTERNOON AND EVENING...BEFORE
DIMINISHING LATER TONIGHT WITH THE LOSS OF HEATING AND BNDRY LYR
STABILIZATION. CAN/T RULE OUT SOME OF THIS CONVECTION MIGRATING E INTO
EXTREME SE OK/ADJACENT SW AR TONIGHT...ALTHOUGH IN A WEAKENED
STATE...THUS HAVE RETAINED SLIGHT MENTION POPS FOR THESE AREAS.

THE PRESSURE GRADIENT WILL AGAIN TIGHTEN ACROSS THE SRN PLAINS MONDAY
AS SFC LOW PRESSURE DEEPENS ONCE AGAIN ALONG THE DRY LINE...THIS TIME
FARTHER S ACROSS THE UPPER RED RIVER VALLEY OF NW TX IN RESPONSE TO
STRONG HEATING...SUCH THAT ANOTHER LAKE WIND ADVISORY WILL LIKELY BE
NEEDED ACROSS MUCH OF THE AREA. SCT STRONG/SVR CONVECTION SHOULD AGAIN
FIRE NEAR THE DRYLINE FROM NW TX INTO CNTRL OK/SE KS MONDAY AFTERNOON
AS THE PRIMARY TROUGH BENEATH THE SD/NE CLOSED LOW ROTATES E INTO THE
SRN ROCKIES. THIS CONVECTION SHOULD ADVANCE ENE FROM N TX THROUGH MUCH
OF OK/NW AR MONDAY NIGHT...WITH ITS REMNANTS AGAIN POSSIBLY REACHING
SE OK/EXTREME NE TX/SW AR LATE. HAVE INCREASED POPS SLIGHTLY TO MID
CHANCE ACROSS SE OK...WITH THIS CONVECTION WEAKENING AS IT APPROACHES
THE AREA AGAIN GIVEN THE STABILIZING BNDRY LYR. HOWEVER...THIS
CONVECTION COULD VERY WELL END UP LEAVING REMNANT CONVECTIVE BNDRYS IN
VC OF THE I-30 CORRIDOR TUESDAY MORNING...WHICH WILL FOCUS MORE
ORGANIZED CONVECTION TUESDAY AFTERNOON/NIGHT AS HEATING/RESULTANT
INSTABILITY IS MAXIMIZED...AND LARGE SCALE FORCING INCREASES WITH THE
APPROACH OF THE UPPER TROUGH AS IT MOVES INTO THE SRN PLAINS.

HAVE BEEFED UP POPS TO LIKELY FOR SE OK/NRN SECTIONS OF SW AR TUESDAY
AFTERNOON AND NIGHT GIVEN THE BETTER MODEL CONSENSUS...WITH A
DEVELOPING SSW LLJ AIDING IN A POTENTIAL MCS DEVELOPMENT FROM SW AR
INTO NE TX TUESDAY NIGHT. SVR POTENTIAL APPEARS TO RAMP UP TUESDAY
AFTERNOON AND EVENING AS MLCAPES RISE TO 3000-3500 J/KG ACROSS SE OK/SW
AR/NE TX. THIS MCS SHOULD SHIFT SE INTO N LA EARLY WEDNESDAY AND
GRADUALLY WEAKEN...AND THUS HAVE KEPT HIGH CHANCE POPS GOING FOR THIS
AREA ALTHOUGH THE CONVECTION SHOULD DIMINISH FROM W TO E DURING THE
AFTERNOON AND EVENING WITH THE DEPARTURE OF THE UPPER TROUGH.

NW FLOW ALOFT WILL FOLLOW THE TROUGH PASSAGE WEDNESDAY AS UPPER
RIDGING DEVELOPS OVER MUCH OF THE PLAINS BENEATH THE UPPER MIDWEST
TROUGH...AND A CLOSED LOW ENTERING THE PAC NW. A WEAK BUT PERSISTENT
SRLY LOW LEVEL FLOW MAY BE ENOUGH TO ENHANCE THE DEVELOPMENT OF SCT
CONVECTION OVER OK/AR THURSDAY THROUGH SATURDAY AS EMBEDDED SHORTWAVE
PERTURBATIONS DRIFT SE ATOP THE UPPER RIDGE AXIS...AND BENEATH THE
MIDWEST TROUGH. THUS...HAVE ADDED SLIGHT CHANCE POPS FOR THIS TIME
PERIOD MAINLY OVER THE NE HALF OF THE AREA. TEMPS THROUGH THE MID AND
LATE WEEK /EXTENDED/ TIMEFRAME SHOULD REMAIN SLIGHTLY ABOVE NORMAL.

PRELIMS TO FOLLOW BELOW...

15

&&

.AVIATION...
MORNING LOW CLOUDS...RISING NORTH FROM THE COAST....BECMG PATCHY
OVER EAST TX LAKES AND CENTRAL LA. DEEPENING SFC LOW OVER UPPER RED
RIVER VALLEY WILL PULL INCREASING SOUTH WINDS INTO AREA TODAY...15
TO 25 KTS AND GUSTY OVER NE TX THIS AFTN...AND AROUND 15 KTS OVER
KMLU AND KELD THIS AFTN. STG MIXING WILL YIELD SCT CU BY AROUND 15Z
TODAY. LOW CLOUDS RETURNING QUICKER TONIGHT...BTWN 07-09Z MON...WITH
SOUTH WINDS OVERNIGHT AROUND 10 TO 15 KTS. /VII/

&&

.PRELIMINARY POINT TEMPS/POPS...
SHV  90  72  89  73  88 /   5   5   5  10  30
MLU  89  72  89  72  88 /   5   0   5   5  20
DEQ  89  71  87  70  82 /   5  20  10  30  60
TXK  90  72  88  72  85 /   5  10  10  20  50
ELD  89  72  89  71  87 /   5   5   5  10  40
TYR  91  72  90  73  86 /   5   5   5  10  30
GGG  91  72  90  73  87 /   5   5   5  10  30
LFK  91  72  90  73  89 /   5   5   5  10  20

&&

.SHV WATCHES/WARNINGS/ADVISORIES...
AR...LAKE WIND ADVISORY FROM 10 AM THIS MORNING TO 8 PM CDT THIS
     EVENING FOR THE FOLLOWING ZONES: ARZ070-071.

LA...LAKE WIND ADVISORY FROM 10 AM THIS MORNING TO 8 PM CDT THIS
     EVENING FOR THE FOLLOWING ZONES: LAZ001-002-010-011-017.

OK...LAKE WIND ADVISORY FROM 10 AM THIS MORNING TO 8 PM CDT THIS
     EVENING FOR THE FOLLOWING ZONES: OKZ077.

TX...LAKE WIND ADVISORY FROM 10 AM THIS MORNING TO 8 PM CDT THIS
     EVENING FOR THE FOLLOWING ZONES:
     TXZ096-097-108>112-124>126-136>138-149>153-165>167.

&&

$$

15/07