Area Forecast Discussion
Issued by NWS St. Louis, MO

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FXUS63 KLSX 040453
AFDLSX

AREA FORECAST DISCUSSION...UPDATED AVIATION
NATIONAL WEATHER SERVICE ST LOUIS MO
1153 PM CDT MON AUG 3 2015

.UPDATE:
ISSUED AT 1008 PM CDT MON AUG 3 2015

ONLY SOME MINOR TWEEKS NEEDED TO THE GOING FORECAST, NAMELY TO
DELAY THE THREAT OF PRECIPITATION TO THE OVERNIGHT HOURS. THE
ANTICYCLONIC TURNING COMPONENT OF THE LOW LEVEL WIND MAX
ORIGINATING FROM THE SOUTHERN/CENTRAL PLAINS AND CYCLONIC FLOW
FROM ILLINOIS INTO THE WESTERN OH VALLEY IS RESULTING IN A
ELONGATED CONFLUENT REGION FROM SOUTHERN NEBRASKA INTO NORTHERN
MO. THIS REGION IS FORECAST TO PERSIST AND INTENSIFY SOME
OVERNIGHT WITH ADDED EASTWARD MOISTURE TRANSPORT FROM THE PLAINS.
SCATTERED SHOWERS AND THUNDERSTORMS ARE EXPECTED TO DEVELOP WITHIN
THIS ELONGATED ZONE CENTERED NORTH OF A COLUMBIA-ST. LOUIS LINE.

GLASS

&&

.SHORT TERM: (THROUGH THE EVENING)
ISSUED AT 240 PM CDT MON AUG 3 2015

UPPER AIR PATTERN CONTINUES TO FEATURE A DEEP TROF ACROSS THE
EASTERN CONUS AND RIDGE ACROSS THE ROCKIES...WHICH KEEPS US FIRMLY
IN NORTHWEST FLOW ALOFT. AT THE SURFACE...THE COLD FRONT CONTINUES
TO SLOWLY DRIFT SOUTH AND WILL EVENTUALLY STALL ACROSS SOUTHWEST
MISSOURI THIS EVENING. A STUBBORN CLUSTER OF SHOWERS AND STORMS THAT
DEVELOPED THIS MORNING ACROSS NORTHWEST MISSOURI CONTINUES TO
DECREASE IN INTENSITY AND COVERAGE AS THEY SINK SOUTHEAST TOWARD ST.
LOUIS.  MEANWHILE...CU FIELD NEAR FRONT IS STARTING TO LOOK A LITTLE
AGITATED SOUTH OF KANSAS CITY TO NEAR VICHY/ROLLA.  WILL GO AHEAD
AND KEEP SOME SLIGHT CHANCES IN FOR THE LATE AFTERNOON AND EARLY
EVENING HOURS TO ACCOUNT FOR THESE TWO AREAS.

CVKING

.LONG TERM: (TONIGHT THROUGH NEXT MONDAY)
ISSUED AT 240 PM CDT MON AUG 3 2015

EXPECT ISOLATED TO SCATTERED THUNDERSTORMS TO DEVELOP LATER
TONIGHT FROM NORTHWEST MISSOURI TO EAST CENTRAL MISSOURI WHERE
AREA OF MOISTURE CONVERGENCE WILL SET UP NORTH OF THE STALLED
SURFACE BOUNDARY. THIS ACTIVITY WILL LINGER TUESDAY MORNING WITH
ADDITIONAL STORMS POSSIBLE TUESDAY AFTERNOON CLOSER TO THE FRONT.

MODEL GUIDANCE IS IN VERY GOOD AGREEMENT THAT A STRONG VORTICITY
MAXIMA/SHORTWAVE WILL SLOWLY MOVE ACROSS THE REGION TUESDAY NIGHT
THROUGH THURSDAY MORNING. EXPECT SHOWERS AND THUNDERSTORMS TO
REDEVELOP TUESDAY EVENING AND INCREASE IN COVERAGE OVERNIGHT AS THE
SYNOPTIC LIFT INCREASES WITH THE APPROACH OF THE VORT MAX AND IS
FURTHER FOCUSED BY THE LOW LEVEL JET INTERSECTING THE FRONTAL ZONE.
THIS AREA OF RAIN SHOULD SLOWLY SHIFT EAST/NORTHEAST ON WEDNESDAY
MORNING WITH ADDITIONAL SHOWERS AND THUNDERSTORMS REDEVELOPING
DURING THE AFTERNOON/EVENING IN VICINITY OF THE FRONT AND SHORTWAVE.
FINALLY THE SYSTEM WILL MOVE EAST OF THE AREA BY THURSDAY
MORNING...BUT NOT BEFORE MOST OF THE AREA SEES 1 TO 3 INCHES OF
RAINFALL. THE POTENTIAL IS CERTAINLY THERE FOR SOME LOCALLY HEAVIER
AMOUNTS...BUT FAIRLY HIGH FLASH FLOOD GUIDANCE AND THE FACT THAT THE
RAIN IS EXPECTED TO FALL OVER A TWO DAY PERIOD PRECLUDES ANY FLOOD
HEADLINES AT THIS TIME.

PATTERN REMAINS ACTIVE AS WE STAY ON THE NORTHEAST FRINGE OF THE
BUILDING RIDGE OF HIGH PRESSURE ALOFT ACROSS THE SOUTHERN PLAINS.
HAD TO INTRODUCE SOME LOW POPS FOR THE WEEKEND AS BOTH THE ECWMF AND
GFS HAVE A SHORTWAVE MOVING ACROSS THE REGION WITH THAT PESKY FRONT
STILL LINGERING NEARBY.

TEMPERATURES WILL GENERALLY BE BELOW NORMAL THROUGH THE ENTIRE SEVEN
DAY FORECAST THANKS TO CLOUD COVER AND PRECIPITATION.

CVKING

&&

.AVIATION:  (FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1144 PM CDT MON AUG 3 2015

LOOKS LIKE THE COLD FRONT IS STALLED...ORIENTED EAST-WEST THROUGH
CENTRAL INTO EAST CENTRAL MISSOURI AND SOUTHERN ILLINOIS. LOW
LEVEL JET IS DEVELOPING AND SOME ISOLATED STORMS ARE POPPING UP
NORTH OF THE FRONT BETWEEN KMBY AND KIRK. EXPECT ADDITIONAL
DEVELOPMENT THROUGH THE NIGHT AFFECTING PRIMARILY NORTHEAST AND
EAST CENTRAL MISSOURI AS WELL AS SOUTHWEST ILLINOIS. STORMS
SHOULD DIMINISH BETWEEN 12-14Z. VFR FLIGHT CONDITIONS ARE
EXPECTED TO PREVAIL OUTSIDE OF THUNDERSTORMS. THE FRONT WILL BEGIN
DRIFTING BACK TO THE NORTH ON TUESDAY...BUT WILL STILL BE IN THE
AREA. SCATTERED THUNDERSTORMS ARE EXPECTED OVER MUCH OF THE AREA
TUESDAY AFTERNOON DUE TO DAYTIME HEATING AND ADDITIONAL LIFT FROM
THE FRONT.

SPECIFICS FOR KSTL:

VFR FLIGHT CONDITIONS ARE EXPECTED TO PREVAIL AT LAMBERT OUTSIDE
OF ANY THUNDERSTORMS WHICH AFFECT THE AIRPORT. THERE IS STATIONARY
FRONT JUST SOUTH OF THE METRO AREA AND A LOW LEVEL JET IS
PRODUCING ISOLATED THUNDERSTORMS NORTH OF IT ACROSS NORTHEAST
MISSOURI. THINK THE COVERAGE WILL REMAIN ISOLATED TO WIDELY
SCATTERED...SO A DIRECT IMPACT TO THE AIRPORT IS QUESTIONABLE.
STORMS SHOULD DISSIPATE/MOVE SOUTH OF THE TERMINAL BETWEEN 12-14Z
TUESDAY. THE FRONT WILL START TO DRIFT BACK NORTHWARD ON TUESDAY
BUT WILL STILL PROVIDE A FOCUS FOR ADDITIONAL THUNDERSTORM
DEVELOPMENT ON TUESDAY AFTERNOON.

CARNEY

&&

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

$$

WFO LSX


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