000
FXUS63 KLSX 191752
AFDLSX

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE ST LOUIS MO
1252 PM CDT SUN MAY 19 2013

.UPDATE...
ISSUED AT 1251 PM CDT SUN MAY 19 2013

MORNING ACTIVITY THAT MOVED THROUGH CENTRAL/NORTHEAST MO...WEST
CENTRAL IL HAS EXITED. OTHERWISE...WARM FRONT TO CONTINUE SLOWLY
LIFTING NORTH THROUGH FORECAST AREA THIS AFTERNOON. COULD STILL SEE SOME
ISOLATED STORMS EARLY THIS AFTERNOON OVER WEST CENTRAL...SOUTHWESTERN
IL...BUT DRY ELSEWHERE. HIGH TEMPS WILL DEPEND ON CLOUD COVER AND
WARM FRONT...FOR NOW HAVE HIGHS IN THE UPPER 80S TO LOW 90S.

BYRD
&&

.SHORT TERM...(THROUGH WEDNESDAY)
ISSUED AT 253 AM CDT SUN MAY 19 2013

ACTIVE WEATHER PATTERN EXPECTED THROUGH WEDNESDAY IN RESPONSE TO
A SERIES OF SHORTWAVES MOVING ACROSS THE REGION AS AN UPPER LOW/TROF
MOVES FROM THE CENTRAL PLAINS TO THE UPPER MISSISSIPPI RIVER VALLEY.
SEVERAL ROUNDS OF SEVERE THUNDERSTORMS APPEAR LIKELY TO OCCUR...WITH
THE POTENTIAL OF LARGE HAIL...DAMAGING WINDS AND TORNADOES.

WARM FRONT IS CURRENTLY LOCATED TO OUR SOUTHWEST AND LINEAR
CONVECTION FROM THE PLAINS CONTINUES TO DECAY AS IT MOVES INTO
WESTERN MISSOURI. PLENTY OF LOW LEVEL STRATUS AND DEBRIS CLOUDS FROM
WESTERN CONVECTION COVER THE CWA EARLY THIS MORNING.

POTENTIAL FOR A WARM DAY WITH 850MB TEMPERATURES RISING ABOVE
+20C...BUT RESIDUAL CLOUD COVER AND LIFTING WARM FRONT HAS ME
CAUTIOUS ABOUT GOING TOO WARM. HAVE GENERALLY FORECAST HIGHS IN THE
MIDDLE TO UPPER 80S...WHICH IS IN LINE WITH LATEST MOS GUIDANCE.
SHORT TERM MODEL GUIDANCE CONTINUES TO SHOW ISOLATED TO SCATTERED
CONVECTION DEVELOPING ALONG AND NORTH OF THE ADVANCING WARM
FRONT...AND LIKELY SOME RESIDUAL BOUNDARY PUSHING EAST FROM THE
DECAYING CONVECTION. 0-6KM BULK SHEAR AND CAPE OF 2000-3000 K/JG
WOULD SUPPORT MULTICELL DEVELOPMENT AND THE POTENTIAL OF SOME
MARGINAL SEVERE HAIL REPORTS IF INITIATION OCCURS. THINK THIS WILL
MAINLY BE ALONG AND EAST OF THE MISSISSIPPI RIVER.

ATTENTION WILL ONCE AGAIN TURN TO OUR WEST LATE THIS EVENING AS
SEVERE CONVECTION IS EXPECTED TO DEVELOP ACROSS EASTERN KANSAS AND
WESTERN MISSOURI...EVENTUALLY DEVELOPING INTO A LINE AND MOVING EAST
TOWARD THE WESTERN CWA BY LATE EVENING. MAIN THREAT WITH THIS
CONVECTION WOULD BE DAMAGING WIND GUSTS. LINE OF CONVECTION WILL
WEAKEN AS IT MOVES FURTHER EAST TOWARD THE MISSISSIPPI RIVER BY
EARLY MORNING WITH LOSS OF INSTABILITY.

ATMOSPHERE SHOULD EASILY RESET FOR MONDAY...WITH THE POTENTIAL FOR A
MAJOR SEVERE WEATHER OUTBREAK TO OCCUR ACROSS AT LEAST THE WESTERN
HALF OF THE CWA DURING THE AFTERNOON AND EVENING HOURS.
INSTABILY/SHEAR COMBINATION IS SUPPORTIVE OF SUPERCELLS WITH LARGE
HAIL...DAMAGING WIND AND TORNADOES.

STILL SOME UNCERTAINTY REGARDING CONVECTIVE TRENDS FOR TUESDAY AND
WEDNESDAY...BUT COULD SEE TWO MORE ACTIVE DAYS GIVEN POSITION OF THE
LONGWAVE TROF TO OUR NORTHWEST AND APPROACHING COLD FRONT. ONCE
AGAIN...SHEAR/INSTABILITY COMBINATION SUPPORTS SUPERCELLS.

COLD FRONT SHOULD FINALLY MOVE THROUGH THE CWA BY WEDNESDAY
NIGHT...ENDING THE SEVERE WEATHER THREAT.

CVKING

.LONG TERM...(THURSDAY THROUGH SATURDAY)
ISSUED AT 253 AM CDT SUN MAY 19 2013

A REINFORCING COLD FRONT WILL PROVIDE ENOUGH LIFT FOR AT LEAST A
CHANCE OF SHOWERS AND THUNDERSTORMS ON THURSDAY. HIGH PRESSURE
RIDGE IN ITS WAKE SHOULD BRING AT LEAST A COUPLE DRY DAYS TO THE
CWA FRIDAY AND SATURDAY BEFORE RETURN FLOW BRINGS INCREASED
CHANCES OF THUNDERSTORMS BACK INTO THE FORECAST FOR THE LATTER
HALF OF THE MEMORIAL DAY WEEKEND. TEMPERATURES WILL REMAIN
SEASONAL WITH HIGHS IN THE 70S AND LOWS IN THE 50S.

CVKING
&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 1251 PM CDT SUN MAY 19 2013

WITH STORMS OUT OF FORECAST AREA...HAVE DRY TAFS FOR NOW WITH
GUSTY SOUTHEAST TO SOUTH WINDS...BEFORE DIMINISHING EARLY THIS
EVENING. NEXT ROUND OF ACTIVITY TO FIRE UP OVER EASTERN KS/WESTERN
MO AND SLIDE EAST OVERNIGHT. STORMS TO REACH KCOU BY 04Z AND KUIN
BY 05Z...COULD SEE MVFR...HIGH END IFR VSBYS/CIGS WITH SOME OF THE
STORMS. AS FOR METRO AREA TAFS...STILL NOT SURE IF STORM COMPLEX WILL
HOLD TOGETHER...SO FOR NOW KEPT VCNTY TS AFTER 09Z. STORMS TO
TAPER OFF FROM WEST TO EAST BY 12Z MONDAY.

SPECIFICS FOR KSTL...WITH STORMS OUT OF FORECAST AREA...HAVE DRY TAFS
FOR NOW WITH GUSTY SOUTHEAST TO SOUTH WINDS...BEFORE DIMINISHING
BY 03Z MONDAY. NEXT ROUND OF ACTIVITY TO FIRE UP OVER EASTERN
KS/WESTERN MO AND SLIDE EAST OVERNIGHT. STILL NOT SURE IF STORM
COMPLEX WILL HOLD TOGETHER AND MAKE IT INTO METRO AREA...SO FOR
NOW KEPT VCNTY TS AFTER 09Z. STORMS TO TAPER OFF BY 12Z
MONDAY...WITH NEXT ROUND FIRING UP BY 21Z MONDAY...SO ADDED VCTS
MENTION DURING THIS PERIOD. SOUTH WINDS TO PERSIST THROUGH THE
REST OF FORECAST PERIOD.

BYRD
&&

.LSX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
IL...NONE.
&&

$$
WFO LSX