National Weather Service Weather Forecast Office

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

000
FXUS63 KLSX 160440
AFDLSX

AREA FORECAST DISCUSSION...UPDATED AVIATION
NATIONAL WEATHER SERVICE ST LOUIS MO
1140 PM CDT WED MAY 15 2013

.UPDATE...
ISSUED AT 922 PM CDT WED MAY 15 2013

FORECAST APPEARS TO BE ON TRACK THIS EVENING WITH CONVECTION
FIRING UP IN THE VICINITY OF THE FRONT WHICH IS ORIENTED EAST-WEST
ACROSS NORTHERN MISSOURI AND CENTRAL ILLINOIS. COVERAGE ISN`T
QUITE AS HIGH AS EXPECTED...BUT I HATE TO LOWER POPS WITH ONGOING
CONVECTION IN THE AREA. WILL KEEP LIKELIES UP THERE FOR THE REST OF
THE EVENING WITH THE EXPECTATION THAT STORMS WILL CONTINUE
DEVELOPING EASTWARD. SHORT RANGE GUIDANCE HAS BEEN VERY CONSISTENT
IN DIMINISHING THE COVERAGE/STRENGTH OF STORMS AFTER 05-06Z AND
THIS IS ALREADY REFLECTED WELL IN THE GOING FORECAST.

CARNEY

&&

.SHORT TERM...(THROUGH LATE TONIGHT)
ISSUED AT 222 PM CDT WED MAY 15 2013

FORECAST REASONING REALLY HAS NOT CHANGED WITH RESPECT TO
THUNDERSTORM CHANCES LATE THIS AFTERNOON AND TONIGHT. TWO AREAS WE
ARE MONITORING...

THE FIRST IS ASSOCIATED WITH A LOBE OF ENERGY ROTATING AROUND THE
UPPER LOW TO OUR SOUTHWEST. SOME CUMULUS STARTING TO DEVELOP FROM
NEAR THE LAKE OF THE OZARKS TO FARMINGTON. LATEST RUNS OF HRRR
CONTINUE TO INITIATE CONVECTION IN THIS AREA AND THEN LIFT IT
NORTHEAST TOWARD THE METRO DURING THE EVENING HOURS. CAN`T RULE
OUT THIS SOLUTION...BUT MODELS CONTINUE TO OVER FORECAST THE LOW
LEVEL MOISTURE WHICH LEADS TO HIGHER THAN OBSERVED INSTABILITY.

THE SECOND AREA IS ALONG THE FRONT WHICH CURRENTLY STRETCHES FROM
JUST NORTH OF ST. JOSEPH MISSOURI TO NEAR KIRKSVILLE AND THEN EAST
ACROSS NORTHERN KNOX AND LEWIS COUNTIES IN MISSOURI AND ADAMS
COUNTY IN ILLINOIS.

HAVE CONFINED CHANCE/LIKELY POPS TO THE SECOND AREA WHERE
FORCING/FOCUS WILL BE GREATER FOR INITIATION. ELSEWHERE...SLIGHT
CHANCE POPS/ISOLATED COVERAGE IS EXPECTED IF INITIATION OCCURS.

SHOULD BE ANOTHER WARM NIGHT AS DEWPOINTS HAVE INCREASED INTO THE
60S AREAWIDE.

CVKING

.LONG TERM...(THURSDAY THROUGH NEXT WEDNESDAY)
ISSUED AT 319 PM CDT WED MAY 15 2013

(THURSDAY THROUGH SATURDAY)

FEEL THAT NAM HAS BEST HANDLE ON FORECAST FOR THE SHORT TERM...AS
GFS IS OVERDOING IT IN REGARDS TO LOW LEVEL MOISTURE...QPF AND
STRENGTH OF SHORTWAVES.

WILL BE DEALING WITH STALLED FRONTAL BOUNDARY OVER NORTHERN PORTIONS
OF FORECAST AREA ON THURSDAY AS WELL AS UPPER LEVEL LOW OVER
NORTHEASTERN OK. SO FORECAST AREA WILL CONTINUE TO BE SQUEEZED
BETWEEN THE TWO WITH BEST CHANCES OF SHOWERS AND THUNDERSTORMS
DURING THE AFTERNOON HOURS. WITH CLOUD COVER AND PCPN...HIGH
TEMPERATURES WILL ONLY BE IN THE MID 70S TO NEAR 80...NEAR NORMAL
FOR THIS TIME OF YEAR.

BY THURSDAY EVENING...FRONTAL BOUNDARY TO LIFT NORTH OF FORECAST
AREA AND UPPER LEVEL LOW OVER NORTHERN AR/SOUTHERN MO TO CONTINUE TO
WEAKEN. SO SHOWERS AND THUNDERSTORMS TO TAPER OFF...WITH JUST A
SLIGHT CHANCE EXPECTED.

ON FRIDAY...WE REMAIN IN WARM SECTOR WITH SOME DIURNAL CU/STORMS
POSSIBLE...BUT WILL BE SCATTERED IN NATURE. HIGHS TO REMAIN NEAR
NORMAL IN THE UPPER 70S TO LOW 80S.

SHOULD SEE ACTIVITY DIMINISH ONCE AGAIN FRIDAY NIGHT...BEFORE
ADDITIONAL DIURNAL STORMS DEVELOP FOR EASTERN PORTIONS OF FORECAST
AREA ON SATURDAY. LOWS FRIDAY NIGHT WILL BE IN THE LOW TO MID 60S
WITH HIGHS ON SATURDAY IN THE LOW TO MID 80S. IT WILL BE A BIT MORE
HUMID ON SATURDAY AS LOW LEVEL MOISTURE IS ON THE INCREASE AND SEE
DEWPTS IN THE MID TO UPPER 60S.

(SATURDAY NIGHT THROUGH WEDNESDAY)

BEYOND THAT...WE REMAIN IN ACTIVE PATTERN THROUGH THE EXTENDED. IT
WILL BE MILD AND DRY SATURDAY NIGHT WITH LOWS IN THE MID TO UPPER
60S.

ON SUNDAY...CONTINUE TO SEE DECENT LOW LEVEL MOISTURE STREAM INTO
AREA AHEAD OF MAIN WEATHER SYSTEM. SO SHOWERS AND THUNDERSTORMS TO
DEVELOP OVER WESTERN/NORTHERN MO...WEST CENTRAL IL SUNDAY...
INCREASING IN COVERAGE SUNDAY NIGHT. MAIN FRONT TO MOVE THROUGH
MONDAY/MONDAY NIGHT WITH BEST CHANCES OF SHOWERS AND
THUNDERSTORMS...SO WENT WITH LIKELY CHANCES. SPC HAS OUTLOOKED AREA
ON MONDAY/MONDAY NIGHT FOR POSSIBLE SEVERE WEATHER AS THERE IS
DECENT INSTABILITY AS WELL AS SHEAR ASSOCIATED WITH UPPER LEVEL TROF
THAT BECOMES CLOSED OFF AND A SECONDARY SPEED MAX THAT WILL ROTATE
OUT OF THE ROCKIES AND INTO THE PLAINS DURING THIS PERIOD. HIGHS
WILL BE IN THE MID TO UPPER 80S SUNDAY AND IN THE UPPER 70S TO MID
80S ON MONDAY.

BECAUSE OF CLOSED OFF NATURE OF THIS SYSTEM...SHOWERS AND
THUNDERSTORM CHANCES TO LINGER THROUGH TUESDAY BEFORE TAPERING OFF
TUESDAY NIGHT. BY TUESDAY AND WEDNESDAY HIGHS WILL BE NEAR NORMAL
IN THE 70S.

BYRD

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 1140 PM CDT WED MAY 15 2013

PCPN AROUND THE UPPER LO TO OUR SW HAS LARGELY DISSIPATED AND IS
NOT EXPECTED TO POSE A THREAT TO THE TERMINALS OVERNIGHT. STALLED
OUT SFC FRONT TO OUR N...FROM KSTJ-KPPQ...HAS INDEED LIT UP WITH
TSRA EARLIER THIS EVENING BUT THIS ACITIVITY HAS SINCE DIMINISHED
WITH A CLUSTER JUST S OF KUIN AND AN ISOLD STORM OVER IN NWRN MO.
LOSS OF HEATING AND ENVIRONMENT NOT FAVORABLE FOR SUSTAINED TSRA
DEVELOPMENT...THIS TREND OF DISSIPATION SHOULD CONTINUE.
OTHERWISE...WILL RESET UNTIL THURSDAY AFTERNOON WITH UPPER LO
PASSING TO OUR S...IT SHOULD GET TSRA RE-FIRED ANEW FOR THE I-70
CORRIDOR TAF SITES BUT KUIN MAY SIT THIS ONE OUT WITH OLD FRONTAL
BOUNDARY EXPECTED TO WASH OUT OR BE TOO WEAK TO DEVELOP TSRA.

SPECIFICS FOR KSTL...VFR CONDITIONS WILL PREVAIL FOR MUCH OF THE
VALID PERIOD WITH A STEADY STREAM OF MID AND HI CLOUDS...A BETTER
CHC OF TSRA IS EXPECTED THURSDAY AFTERNOON WITH CLOSEST APPROACH
OF UPPER LEVEL SYSTEM JUST TO THE S...MVFR CIGS EXPECTED TO
DEVELOP OR MOVE IN LATE THURSDAY NIGHT.

TES

&&

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

$$

WFO LSX