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000
FXUS63 KLSX 190755
AFDLSX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ST LOUIS MO
255 AM CDT SUN MAY 19 2013

.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 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1147 PM CDT SAT MAY 18 2013

AN AREA OF STRATUS HAD REACHED KCOU AND WAS MOVING NEWD AT TAF
ISSUANCE. THIS CLOUD DECK MAY PRODUCE BRIEF PDS OF MVFR CIGS AT
METRO AREA TAF SITES. SCT SHOWERS MAY AFFECT THE TERMINALS TOWARDS
DAYBREAK HOWEVER THE BEST PCPN CHCS WILL BE TOWARDS OR BEYOND THE
END OF THE 24HR TAF PD. SELY WINDS WILL TURN SLY AND GUST TO
AROUND 20 KTS DURING THE AFTN.

SPECIFICS FOR KSTL...AN AREA OF STRATUS WAS MOVING NEWD TOWARDS
THE TERMINAL AND MAY PRODUCE A BRIEF PD OF MVFR CIGS BEFORE 09Z
HOWEVER THE OBS ACROSS THE PORTION OF THE STRATUS HEADED TOWARDS
KSTL WAS GENERALLY VFR AT TAF ISSUANCE. SCT SHOWERS MAY AFFECT
THE TERMINAL TOWARDS DAYBREAK HOWEVER THE BEST PCPN CHCS WILL BE
TOWARDS THE END OF THE 30HR TAF PD. SELY WINDS WILL TURN SLY AND
GUST TO AROUND 20 KTS DURING THE AFTN.

KANOFSKY

&&

.PRELIMINARY POINT TEMPS/POPS...
SAINT LOUIS     89  74  87  67 /  30  40  50  80
QUINCY          86  67  84  66 /  30  70  50  70
COLUMBIA        87  67  83  65 /  10  60  60  80
JEFFERSON CITY  87  67  85  65 /  10  60  60  80
SALEM           86  70  87  70 /  30  30  30  60
FARMINGTON      86  69  85  68 /  20  30  30  80

&&

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

$$

WFO LSX