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000
FXUS63 KSGF 180438
AFDSGF

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SPRINGFIELD MO
1138 PM CDT FRI MAY 17 2013

.SYNOPSIS...
ISSUED AT 255 PM CDT FRI MAY 17 2013

CURRENTLY WE HAVE AN UPPER LEVEL TROUGH OF LOW PRESSURE SLOWLY
EDGING EAST ACROSS SOUTHERN MISSOURI THIS AFTERNOON. A FEW
ISOLATED SHOWERS HAVE DEVELOPED IN THE EASTERN OZARKS...HOWEVER
MOST OF THE CONVECTION HAS DEVELOPED OUT AHEAD OF THIS UPPER LEVEL
FEATURE. THE MAIN UPPER LEVEL TROUGH WHICH WILL BRING THE WEATHER
TO THE CENTRAL U.S. THIS WEEKEND AND EARLY NEXT WEEK WAS STILL OUT
IN THE WESTERN U.S.

THE MAIN FOCUS WITH THIS FORECAST PACKAGE WILL BE THE POTENTIAL OF
STRONG TO SEVERE STORMS DEVELOPING LATE THIS WEEKEND INTO EARLY
NEXT WEEK AS THIS UPPER LEVEL TROUGH STRENGTHENS AND PUSHES EAST
INTO THE PLAINS.

&&

.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 255 PM CDT FRI MAY 17 2013

ISOLATED SHOWERS AND THUNDERSTORMS WILL REMAIN POSSIBLE ACROSS THE
EASTERN OZARKS THIS AFTERNOON INTO THE EARLY EVENING AS AN UPPER
LEVEL TROUGH SHIFTS EAST ACROSS SOUTHERN MISSOURI. CONVECTION
SHOULD END AROUND SUNSET AS ANY INSTABILITY DECREASES.

LOW LEVEL MOISTURE ADVECTION WILL CONTINUE TONIGHT. COULD SEE
REDEVELOPMENT OF LOW CLOUDS AND LIGHT FOG...ESPECIALLY AROUND THE
AREA LAKES AND IN LOW LYING AREAS. LOW LEVEL JET WILL DEVELOP OVER
THE SOUTHERN PLAINS AND INTO SOUTHERN KANSAS LATE TONIGHT.

UPPER LEVEL RIDGE WILL BUILD INTO THE AREA SATURDAY WITH MOISTURE
ADVECTION CONTINUING TO BRING IN MUCH HIGHER GULF MOISTURE. DEW
POINTS SHOULD RISE INTO THE MID TO UPPER 60S. WILL KEEP THINGS DRY
FOR NOW WITH THERMAL CAPPING EXPECTED...BUT WILL NEED TO MONITOR
POTENTIAL OF SCATTERED THUNDERSTORMS AS SOME MODEL DATA SHOWING
SOME SHORTWAVE ENERGY EJECTING OUT OF THE MAIN LOW INTO THE AREA.
HAVE INCREASED POPS UP TO 14 PERCENT AT THIS TIME.

.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 255 PM CDT FRI MAY 17 2013

INGREDIENTS APPEAR TO BE COMING TOGETHER FOR SEVERE WEATHER LATER
SUNDAY INTO EARLY NEXT WEEK.

AN UPPER LEVEL RIDGE WILL MIGRATE ACROSS THE REGION SATURDAY NIGHT
AS AN UPPER LEVEL TROUGH DIGS INTO THE ROCKIES. AN ISOLATED ELEVATED
STORM CANNOT BE RULED OUT SATURDAY NIGHT WITH THE AID OF A STRENGTHENING
LOW LEVEL JET...WEAK ISENTROPIC UPGLIDE...AND PASSAGE OF A MINOR
IMPULSE RIDING OVER TOP THE UPPER RIDGE.

ON SUNDAY...THE UPPER LEVEL TROUGH WILL COME OUT OF THE ROCKIES INTO
THE PLAINS AND TAKE ON A MORE NEGATIVE TILT. MEANWHILE A SURFACE
LOW WILL DEVELOP AND TRACK FROM WESTERN KANSAS INTO EASTERN
NEBRASKA. VERY WARM AND BREEZY CONDITIONS WILL OCCUR OUT AHEAD
THIS SYSTEM ACROSS THE OZARKS. THE LOWER TROPOSPHERE WILL BECOME
MODERATELY UNSTABLE BUT REMAIN CAPPED MUCH OF THE DAY ACROSS THE
OZARKS AND OSAGE PLAINS.

A POWERFUL UPPER JET WILL PUNCH INTO THE PLAINS SUNDAY AFTERNOON AND
EVENING WHILE THE SURFACE COLD FRONT EDGES EASTWARD. STRONG DEEP
LAYER SHEAR GREATER THAN 40 KTS WILL OVERSPREAD THE AREA LATE SUNDAY
AFTERNOON AND EVENING AS THE TROUGH BECOMES NEGATIVE TILTED ACROSS THE
EASTERN PLAINS. LOW LEVEL SHEAR PROFILES MAY BE ENHANCED SUNDAY
EVENING AS THE LOW LEVEL JET STRENGTHENS.

WHILE THE OVERALL SIGNAL FOR SEVERE WEATHER REMAINS FAIRLY UNCHANGED
THERE REMAINS UNCERTAINTY ON THE EXACT TIMING AND EVOLUTION OF THIS
POTENTIAL SEVERE WEATHER EVENT.

IN GENERAL EXPECT CONVECTION TO IGNITE ACROSS THE PLAINS SUNDAY
AFTERNOON THEN SPREAD EAST TOWARD WESTERN MISSOURI LATE SUNDAY
AFTERNOON AND EVENING AS STRONG HEIGHT FALLS SHIFT EAST AND THE
REGION COMES UNDER THE INFLUENCE OF INCREASING JET DYNAMICS.

STORM MODE MAY EVOLVE FROM SUPERCELLS TO MORE OF A LINEAR CONVECTIVE
COMPLEX BUT THESE DETAILS REMAIN UNCERTAIN. IN ANY EVENT STRONG TO
POTENTIALLY SEVERE THUNDERSTORMS WILL IMPACT LOCATIONS GENERALLY
NORTHWEST OF BRANSON TO ROLLA LINE SUNDAY NIGHT AND ESPECIALLY WEST
OF HIGHWAY 65.

ON MONDAY...THE UPPER TROUGH WILL SHIFT INTO THE NORTHERN PLAINS
WHICH WILL MAINTAIN A BELT OF WESTERLIES ACROSS THE REGION. THE
ASSOCIATED COLD FRONT WILL SAG SOUTHWARD INTO THE REGION AND BECOME
ORIENTED PARALLEL WITH THE FLOW ALOFT. AMPLE INSTABILITY AND DEEP
LAYER SHEER WILL BE IN PLACE TO SUPPORT STRONG TO SEVERE STORMS. IN
ADDITION A RICH SUPPLY OF MOISTURE WILL INTERACT WITH THE FRONT TO
SUPPORT HEAVY RAINFALL RATES. GIVEN THE ORIENTATION OF THE FRONT AND
THE POTENTIAL FOR TRAINING STORMS THE RISK FOR FLOODING WILL
INCREASE MONDAY AND MONDAY NIGHT.

ON TUESDAY...MODELS DIFFER ON THE TIMING OF THE FRONTAL PASSAGE BUT
IN GENERAL HAVE SLOWED IT DOWN. THIS WILL MAINTAIN THE POTENTIAL OF
SEVERE WEATHER AND FLOODING INTO TUESDAY ESPECIALLY EAST OF
HIGHWAY 65.

FOR THE REMAINDER OF NEXT WEEK...THE UPPER TROUGH WILL TRANSITION
TO THE EASTERN U.S. WHILE AN UPPER RIDGE BUILDS ACROSS THE REGION.
MODELS SUGGEST WEAK DISTURBANCES MAY BRING PERIODIC CHANCES OF
SHOWERS. HOWEVER THERE IS CONSIDERABLE UNCERTAINTY ON THE DETAILS
OF THE FORECAST LATER NEXT WEEK.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 1150 PM CDT FRI MAY 17 2013

UPPER LEVEL RIDGING WITH ITS AXIS OVER THE CENTRAL AND SOUTHERN
PLAINS THIS EVENING WILL SHIFT EASTWARD OVER THE NEXT EIGHTEEN TO
TWENTY FOUR HOURS TOWARD WESTERN MISSOURI. AT THE SURFACE A WEAK
BUT INCREASINGLY MOIST SOUTHERLY FLOW OF AIR WILL DOMINATE THE
WEATHER OVER SOUTHWESTERN MISSOURI THROUGH THE TAF FORECAST
PERIOD. BECAUSE OF THIS STRONG LOW LEVEL MOISTURE INFLUX AND HIGH
PRESSURE ALOFT...INCLUDED A PERIOD OF MVFR EARLY TOMORROW MORNING
AT ALL THREE AIRFIELDS DUE TO CEILING`S. A WEAK MID LEVEL
DISTURBANCE APPROACHING FROM THE SOUTHWEST WILL BRING THE CHANCE
OF SOME SHOWER AND WEAK THUNDERSTORM ACTIVITY TO FAR SOUTHWESTERN
MISSOURI THIS AFTERNOON.

&&

.SGF WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
KS...NONE.
&&

$$

SYNOPSIS...LINDENBERG
SHORT TERM...LINDENBERG
LONG TERM...FOSTER
AVIATION...COLUCCI