Heavy Rain in Missouri, August 30, 2003

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PADUCAH KY
430 AM CDT SAT AUG 30 2003

MAIN CONCERN FOR THIS FORECAST CONTINUES TO BE PRECIPITATION CHANCES
AND POTENTIAL FOR HEAVY RAINFALL THROUGH THE LONG WEEKEND.

BASED ON SURFACE DEWPOINTS THE TRUE FRONT IS WELL NORTH OF THE QUAD
STATE...SOMEWHERE ACROSS NORTHERN ILLINOIS AND INDIANA...EARLY THIS
MORNING.  THE MORE AFFECTIVE BOUNDARY...THE OUTFLOW BOUNDARY FROM
YESTERDAYS STORMS...IS LOCATED ALONG THE KY/TN BORDER.

RADAR INDICATES NUMEROUS SHOWERS AND SCATTERED THUNDERSTORMS ACROSS
THE MIDDLE PORTIONS OF THE FORECAST AREA...IN ASSOCIATION WITH A
RATHER WEAK MID-LEVEL DISTURBANCE THAT WAS INDUCING WARM ADVECTION
OVER THE SURFACE BOUNDARY.  THE ETA/MESOETA PICK UP ON THIS AND
PRODUCE WIDESPREAD RAINFALL ACROSS ROUGHLY  THE SOUTHERN HALF OF THE
AREA AT LEAST DURING THE MORNING.  AS THE WEAK DISTURBANCE MOVES
EAST OF THE AREA...THE PRECIPITATION WILL SLOWLY DISSIPATE THIS
AFTERNOON FROM WEST TO EAST.  HAVE CATEGORICALS AND A MENTION OF
HEAVY RAIN GOING FOR TODAY ACROSS ALL BUT THE NORTHWEST QUADRANT OF
THE FORECAST AREA.

THERE COULD BE SOME SCATTERED DIURNAL CONVECTION THIS AFTERNOON AND
EARLY THIS EVENING...ESPECIALLY TO THE NORTH OF THE MAIN
PRECIPITATION SHIELD...AND NEAR ANY OUTFLOW BOUNDARIES.
TEMPERATURES WILL BE STUNTED CONSIDERABLY IN MOST LOCATIONS...SO
DONT LOOK FOR MORE THAN AROUND 10 DEGREES OF WARMING TODAY.

GENERALLY FOLLOWED THE ETA/MESOETA FOR THIS FORECAST.  LOOK FOR
PERIODS OF WARM ADVECTION INDUCED SHOWERS AND THUNDERSTORMS FROM
OVERNIGHT TONIGHT...THROUGH SUNDAY NIGHT.  THE TIMING AND LOCATION
OF INDIVIDUAL EPISODES WILL BE DIFFICULT TO TELL...SO HAVE JUST
BROAD BRUSHED LIKELY POPS THROUGHOUT THE QUAD STATE.  THE GENERAL
TREND IS FOR EACH NEW EPISODE TO BE FURTHER NORTH AND WEST...AS THE
INVERTED SURFACE TROUGH DEVELOPS TO OUR WEST...IN RESPONSE TO THE
MAIN MID/UPPER LEVEL SYSTEM MOVING OUT ONTO THE CENTRAL PLAINS.
HAVE INCORPORATED THIS TREND BY POSTING ONLY CHANCE POPS IN THE FAR
SOUTHEAST FOR SUNDAY NIGHT...WITH LIKELIES ELSEWHERE.

IT APPEARS THAT A COUPLE INCHES OF RAIN WILL BE POSSIBLE OVER THE
WEEKEND...BUT AM NOT SURE IF RAINFALL RATES WILL BE HIGH ENOUGH TO
CAUSE FLOODING WITH ANY INDIVIDUAL ROUND OF CONVECTION.
HOWEVER...THE CUMULATIVE AFFECT MAY LEAD TO MORE OF A GENERAL
FLOODING PROBLEM LATER SUNDAY INTO MONDAY.  WILL NOT MENTION HEAVY
RAINS BEYOND THE FIRST PERIOD...BUT WILL ADDRESS HEAVY RAIN
POTENTIAL IN THE HWO.  CONFIDENCE IS TOO LOW FOR A FLOOD WATCH AT
THIS TIME.

THE MAIN MID/UPPER LEVEL SYSTEM AND SURFACE TROUGH MOVE EASTWARD
INTO THE AREA LATE MONDAY AND MONDAY NIGHT.  MUCH OF THE AREA MAY BE
IN THE WARM SECTOR DURING THE DAY MONDAY...THUS HAVE CHANCE POPS FOR
MONDAY ACROSS WESTERN KENTUCKY...AND FAR SOUTHERN ILLINOIS...WITH
LIKELIES ELSEWHERE.  WILL BREAK OUT THE BROAD BRUSH FOR LIKELY POPS
MONDAY NIGHT AS THE SURFACE TROUGH AND LINE/BAND OF CONVECTION MOVE
THROUGH MUCH OF THE FORECAST AREA.  WILL KEEP CHANCE POPS FOR
TUESDAY WITH BEST CHANCE IN THE EAST...AND THEN LIMIT LOW POPS TO
THE EASTERN HALF OF THE AREA FOR TUESDAY NIGHT.

KEPT WEDNESDAY DRY FOR NOW.  HOWEVER...THE ECMWF TRIES TO HOLD UP
THE SURFACE TROUGH...AS A RATHER VIGOROUS UPPER TROUGH DESCENDS INTO
THE GREAT LAKES WITH A STRONG SURFACE SYSTEM.  IF THIS HAPPENS WOULD
NOT BE SURPRISED TO HAVE POPS EXTENDED THROUGH
WEDNESDAY...ESPECIALLY IN THE EASTERN PORTIONS OF THE AREA.

TEMPERATURES WILL GENERALLY BE STUCK IN AROUND A 10 DEGREE RANGE
THROUGH THE WEEKEND.  THERE WILL BE SOME DRIER AIR MOVING IN BEHIND
THE SURFACE TROUGH MONDAY NIGHT AND TUESDAY...SO LOWS WILL
EVENTUALLY FALL TO NEAR 60 FOR MUCH OF NEXT WEEK.  HOWEVER...HIGHS
WILL NOT CHANGE MUCH FROM THIS WEEKENDS LEVELS...WHICH WILL BE A BIT
BELOW NORMAL.

AS FOR SHORT TERM TEMPERATURE GUIDANCE...GENERALLY STAYED WITHIN THE
RATHER SMALL RANGE PROVIDED.  HOWEVER...DID GO ABOVE IT A BIT IN
SOME LOCATIONS FOR SUNDAY NIGHT.

.PAH...NONE.

DRS

ILZ075>078-080>094-INZ081-082-085>088-KYZ001>022-MOZ076-086-087-100-
107>112-114-311000-

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE PADUCAH KY
500 AM CDT SAT AUG 30 2003

...WIDESPREAD HEAVY RAINFALL POSSIBLE OVER THE LABOR DAY WEEKEND...

THIS HAZARDOUS WEATHER OUTLOOK IS FOR SOUTHEAST MISSOURI...SOUTHERN
ILLINOIS...SOUTHWEST INDIANA AND WESTERN KENTUCKY.

.DAY ONE...TODAY AND TONIGHT

NUMEROUS THUNDERSTORMS ARE EXPECTED ACROSS THE QUAD STATE TODAY AND
TONIGHT.  A LARGE AREA OF THUNDERSTORMS IS EXPECTED TO SLOWLY PUSH
EASTWARD ACROSS THE QUAD STATE THIS MORNING...AND COME TO AN END
FROM WEST TO EAST THIS AFTERNOON.  RAINFALL AMOUNTS OF AN INCH OR
MORE WILL BE POSSIBLE...MAINLY ACROSS WESTERN KENTUCKY.  WIDESPREAD
FLOODING PROBLEMS ARE NOT EXPECTED.

ANOTHER AREA OF THUNDERSTORMS IS EXPECTED TO DEVELOP ACROSS THE QUAD
STATE AFTER MIDNIGHT TONIGHT.  THIS AREA OF STORMS IS EXPECTED TO
LIFT SLOWLY NORTHWARD ACROSS THE AREA THROUGH SUNDAY MORNING.  THIS
ROUND OF STORMS MAY ALSO RESULT IN UP TO AN INCH OF RAINFALL ACROSS
MUCH OF THE QUAD STATE.  THE HEAVIEST RAINS OVERNIGHT WILL LIKELY
FALL TO THE NORTH OF THE EARLIER HEAVY RAINS...SO WIDESPREAD
FLOODING PROBLEMS ARE NOT EXPECTED.

.DAYS TWO THROUGH SEVEN...SUNDAY THROUGH FRIDAY

A FEW MORE ROUNDS OF THUNDERSTORMS ARE EXPECTED ACROSS THE QUAD
STATE FROM SUNDAY THROUGH TUESDAY.  MARGINAL INSTABILITY AND
RELATIVELY STRONG WIND FIELDS MAY SUPPORT THE DEVELOPMENT OF A FEW
ORGANIZED SEVERE STORMS ACROSS SOUTHEAST MISSOURI SUNDAY AFTERNOON
AND EVENING...BUT THE PRIMARY THREAT THROUGH THE PERIOD WILL
CONTINUE TO BE WIDESPREAD HEAVY RAINS.

WITH EACH SUCCESSIVE ROUND OF THUNDERSTORMS AND HEAVY
RAINFALL...FLOODING PROBLEMS WILL BECOME MORE LIKELY...AS THE GROUND
BECOMES OVERLY SATURATED.  EXTREME RAINFALL RATES AND FLASH FLOODING
ARE NOT EXPECTED DUE TO ONLY MARGINAL INSTABILITY IN THE
REGION...BUT PERSISTENT RAINFALL OVER SATURATED GROUNDS MAY LEAD TO
MORE OF A GENERAL HIGH WATER THREAT THROUGH THE LATER HALF OF THE
WEEKEND.  A FLOOD WATCH MAY NEED TO BE ISSUED...IF AND
WHEN...FORECAST CONFIDENCE IN THE TIMING AND LOCATION OF THE
HEAVIEST RAINFALL INCREASES.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION MAY BE REQUESTED ACROSS SOUTHEAST MISSOURI SUNDAY
AFTERNOON AND EVENING.  IN ADDITION...ANY REPORTS OF HEAVY RAINFALL
OR FLOODING PROBLEMS THROUGHOUT THE QUAD STATE OVER THE HOLIDAY
WEEKEND WOULD BE GREATLY APPRECIATED.

DRS