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000
FXUS64 KSHV 182117
AFDSHV

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SHREVEPORT LA
417 PM CDT SAT MAY 18 2013

.DISCUSSION...
QUIET WEATHER SHOULD CONTINUE TONIGHT AND ANOTHER DAY OF ABOVE
NORMAL TEMPERATURES IS EXPECTED AS A SHORTWAVE RIDGE MOVES ACROSS
THE REGION. BY SUNDAY AFTERNOON...A LARGE NEGATIVELY TITLED UPPER
TROUGH SHOULD BEGIN TO SLOWLY MOVE EWD INTO THE CNTRL PLAINS. THIS
WILL HELP PUSH A DRYLINE/PACIFIC COLD FRONT EAST OF THE I-35
CORRIDOR. STRONG TO SEVERE CONVECTION IS EXPECTED TO DEVELOP
AHEAD OF THIS FRONT...AND FOR THE MOST PART...SHOULD STAY NORTH
AND WEST OF THE CWA. HOWEVER...SOME STORMS MAY WORK THEIR WAY INTO
SE OK AND ADJACENT PORTIONS OF EXTREME NE TX/SW AR SUNDAY EVENING.
SEVERE WEATHER WILL BE POSSIBLE.

MOVEMENT OF THE UPPER TROUGH ACROSS THE PLAINS WILL BE QUITE SLOW
SO A SIMILAR SETUP IS EXPECTED FOR MONDAY BUT EVERYTHING SHOULD BE
SLIGHTLY FARTHER EAST AT THE START. ANOTHER ROUND OF STRONG TO
SEVERE CONVECTION SHOULD DEVELOP TO OUR NORTH DURING THE
AFTERNOON ON MONDAY. UPPER TROUGH AXIS WILL GAIN A MORE NEUTRAL
TILT WITH TIME AND THIS SHOULD HELP TO PUSH THE SFC BOUNDARIES
FARTHER EAST. CONVECTION IS EXPECTED TO DEVELOP INTO AN MCS AND
SPREAD SOUTH AND EAST INTO THE CWA LATE MONDAY WITH MORE
REDEVELOPMENT DURING THE DAY TUESDAY. INSTABILITY AND VERTICAL
SHEAR PROFILES ARE SUPPORTIVE OF ALL MODES OF SEVERE
WEATHER...ESPECIALLY TUESDAY AFTERNOON THROUGH EARLY WEDNESDAY
MORNING. FORECAST SOUNDINGS INDICATE DIRECTIONAL SHEAR MAY BE
MARGINAL WHICH SUGGESTS LINEAR CONVECTION WILL BE THE FAVORED
MODE. AXIS OF THE UPPER TROUGH SHOULD MOVE THROUGH THE CWA BY
THURSDAY MORNING WHICH SHOULD END PRECIP CHANCES FOR A LITTLE
WHILE.

FCST BECOMES INCREASINGLY UNCERTAIN BEYOND THURSDAY. BOTH
THE GFS AND THE ECMWF SHOW A LARGE RIDGE BUILDING ACROSS THE CNTRL
CONUS...WHICH WOULD SIGNAL A BIG PATTERN SHIFT. THE KEY TO THE
EXTENDED FCST WILL BE WHERE THE RIDGE AXIS BECOMES ESTABLISHED.
BOTH MODELS KEEP THE RIDGE AXIS WELL TO THE WEST. THIS PATTERN
WOULD BE MORE TYPICAL OF EARLY JUNE IS USUALLY A VERY WET PATTERN
FOR US. AS WEAK UPPER TROUGHS RIDE AROUND THE RIDGE...CONVECTIVE
COMPLEXES SHOULD DEVELOP ACROSS THE HIGH PLAINS WHICH THEN MOVE
SEWD TOWARDS THE CWA. THIS PATTERN REPEATS ALMOST EVERY DAY AND
ANY REMNANT OUTFLOW BOUNDARIES COULD ALSO PROVIDE A FOCUS FOR
TSTM DEVELOPMENT MUCH CLOSER TO THE AREA. UNFORTUNATELY...THIS
ALSO MAKES IT DIFFICULT TO DO ANYTHING OTHER THAN BROAD BRUSH
SLIGHT CHANCE TO CHANCE POPS JUST ABOUT EVERY DAY DURING THE
EXTENDED PERIODS. ON THE UP SIDE...IT ALSO KEEPS RAIN CHANCES IN
THE FCST.

TEMPS SHOULD GENERALLY REMAIN FAIRLY CONSTANT WITH AFTERNOON HIGHS
IN THE MID 80S TO NEAR 90 DEGREES. IF THE RAIN FAILS TO DEVELOP IN
THE EXTENDED PERIODS...TEMPS WILL LIKELY BE MUCH WARMER THAN
CURRENTLY FCST. /09/


&&

.AVIATION...
ON THE BACK SIDE OF UPPER RIDGE AXIS THAT HAS MOVED EAST OF THE FOUR
STATE REGION THE FLOW HAS SHIFTED TO THE WEST AND SOUTHWEST WHICH
WILL BE RETURNING HIGH LEVEL MOISTURE INTO THE AREA. IN THE LOWER
LEVELS THE REGION WILL BE ON THE BACK SIDE OF SURFACE HIGH PRESSURE
TO THE EAST...AND WITH DEEPENING SURFACE LOW PRESSURE OVER THE
PLAINS AND INTO WEST TEXAS...THE SOUTHERLY FLOW WILL BE PRODUCING A
PRESSURE GRADIENT RESULTING IN SOUTHERLY SURFACE WINDS WITH HIGHER
GUSTS AND AN INCREASE IN GULF MOISTURE. VFR FLIGHT CATEGORIES WILL
BECOME MVFR AND IFR AFTER 19/06 UTC SUNDAY AND LINGER INTO THE MID
MORNING HOURS ON SUNDAY UNTIL THE CEILINGS SCATTERED UTC AND LIFT
BETWEEN 19/15 UTC TO 19/17 UTC. WIND SPEEDS WILL REMAIN BETWEEN 8 TO
15 KNOTS OVERNIGHT AND INCREASE TO 13 TO 20 KNOTS AFTER 19/15 UTC
WITH HIGHER GUSTS TO 20 TO 25 KNOTS. THE SURFACE WINDS WILL LOWER
SOME AFTER 20/00 UTC MONDAY...BUT STILL RANGE FROM 8 TO 13 KNOTS.
/06/

&&

.PRELIMINARY POINT TEMPS/POPS...
SHV  71  90  73  89  72 /  10  10  10  10  10
MLU  72  88  72  88  71 /  10  10  10  10  10
DEQ  70  88  72  86  69 /  10  10  20  20  30
TXK  70  89  73  86  71 /  10  10  10  10  20
ELD  71  87  72  88  70 /  10  10  10  10  10
TYR  69  92  71  89  73 /  10  10  10  10  10
GGG  70  91  72  88  72 /  10  10  10  10  10
LFK  71  93  72  90  73 /  10  10  10  10  10

&&

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

$$

09/06