Flash Flood Warning 103, NWS Memphis, TN

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MEMPHIS TN
911 PM CDT TUE MAY 27 2008

.UPDATE...

A COLD FRONT EXTENDS FROM SOUTHERN MISSOURI INTO OHIO VALLEY THIS
EVENING. MEANWHILE...A VERY MOIST AND MARGINALLY UNSTABLE AIRMASS
COVERS THE MID SOUTH AND THUNDERSTORMS CONTINUE TO DEVELOP IN
RESPONSE TO A WEAK MID LEVEL SHORTWAVE MOVING THROUGH THE REGION.
THE SEVERE THREAT CONTINUES TO DIMINISH WITH SBCAPES OF 500 TO
1000 J/KG AND LIFTED INDEX VALUES AROUND -2C. A FEW STORMS COULD
PRODUCE 40 MPH GUSTS AND SMALL HAIL. HOWEVER...HEAVY RAIN THREAT
WILL CONTINUE FOR A LEAST THE NEXT FEW HOURS. PRECIPITABLE WATER
VALUES AROUND 2 INCHES COMBINED WITH WEAK WINDS ALOFT ARE
COMBINING TO CREATE LOCALLY HEAVY RAINFALL. THE CLUSTER OF STORMS
FROM UNION CITY TO SOMERVILLE WILL BE MOVING EAST INTO AREA THAT
HAVE SEEN A LOT OF RAIN OVER THE LAST 2 DAYS AND WE WILL BE
MONITORING FOR ADDITIONAL FLOODING.

THE COLD FRONT WILL SLOWLY WORK SOUTH INTO NORTHERN SECTIONS OF
THE MID SOUTH BY MORNING. REGIONAL RADAR DEPICTS SOME
DEVELOPMENT ALONG THE FRONT IN SOUTHERN MISSOURI AND AS A RESULT
WILL LEAVE RAIN CHANCES ALONE FOR THE REMAINDER OF THE NIGHT.
ONGOING FORECAST HANDLES SITUATION WELL WITH NO CHANGES PLANNED.

&&

.PREV DISCUSSION... /ISSUED 334 PM CDT TUE MAY 27 2008/

POSSIBLE HEAVY RAINFALL...FLASH FLOODING...AND SEVERE
THUNDERSTORMS LATE THIS AFTERNOON AND THIS EVENING ARE THE MAIN
CONCERNS.

LATEST MODELS WERE IN DECENT AGREEMENT FOR THE NEXT SEVERAL DAYS.
USED A BLEND OF THEM. DID NOT MAKE MAJOR CHANGES TO THE PREVIOUS FORECAST.

AT 330 PM CDT...HEAVY RAINFALL WITH NUMEROUS SHOWERS AND
THUNDERSTORMS WAS OCCURRING OVER NORTHEAST MISSISSIPPI.
ADDITIONAL WEAKENING SHOWERS WERE NEAR UNION CITY TENNESSEE.
TEMPERATURES RANGED FROM THE UPPER 60S NEAR SAVANNAH TENNESSEE WHERE
RAIN HAS COOLED THE AIR TO THE UPPER 80S NEAR TUNICA MISSISSIPPI.
SEVERAL WEAK MID LEVEL LOW PRESSURE DISTURBANCES/SHORT WAVES WERE
NEARBY AND A MAIN COLD FRONT WAS LOCATED FROM SOUTHWEST MISSOURI
TO SOUTHERN INDIANA.

THROUGH 10 PM CDT...MONITORING FOR POSSIBLE REDEVELOPMENT OF SHOWERS
AND STORMS WEST OF A UNION CITY TN TO CLARKSDALE MS LINE...
INCLUDING THE MEMPHIS AND JONESBORO AR AREAS. THESE AREAS HAVE
ESCAPED THE HEAVIEST RAINFALL AND SHOWERS/STORMS TODAY AS A COLD
POOL/STABLE AIR FROM A EARLIER DECAYING MCS MOVED THROUGH.
THESE AREAS HAVE BEEN EXPERIENCING A GOOD AMOUNT OF SUN OVER
THE PAST FEW HOURS...ALLOWING TEMPERATURES TO REBOUND.
WITH INSTABILITY FORECAST TO INCREASE WITH LIFTED INDICES FORECAST
IN THE -4 TO -8 RANGE...THINK REDEVELOPMENT WILL OCCUR WITH A FEW
STRONG TO SEVERE STORMS. ANY STORM WILL BE SLOW MOVING AND PULSE
TYPE WITH HEAVY RAINFALL AND DAMAGING WINDS THE MAIN HAZARDS.
NO CONVECTIVE WATCHES...SEVERE THUNDERSTORM OR FLASH FLOOD...ARE
ANTICIPATED AS ANY SEVERE/FLOODING POTENTIAL WILL BE LOCALIZED.
THESE STORMS SHOULD DIMINISH WITH THE LOSS OF DAYTIME HEATING.

ACROSS THE REST OF THE MIDSOUTH....THINK THE CURRENT SHOWERS
AND STORMS OVER NE MS WILL CONTINUE TO WEAKEN AND PUSH EAST OF
THE FORECAST AREA...BUT STILL MAY DUMP ANOTHER INCH OR TWO
THIS AFTERNOON. BELIEVE RAIN SOAKED AREAS NEAR THE TN RIVER IN
WEST TN WILL NOT GET MUCH MORE HEAVY RAIN AS THE AIR HAS BEEN
WORKED OVER AND IS STABLE FROM TODAY/S SHOWERS AND STORMS.
REGARDLESS...SOME SHOWERS AND STORMS MAY DEVELOP THIS EVENING.

AFTER 10 PM CDT TONIGHT...THINK MOST...IF NOT ALL CONVECTION...
WILL DIE DOWN...ESPECIALLY WITH WEAK WINDS AND LACK OF A LOW
LEVEL JET TO IMPORT MOISTURE AND ADDITIONAL INSTABILITY.
THE SURFACE FRONT SHOULD SAG SOUTH INTO AREAS NORTH OF INTERSTATE
40 AFTER MIDNIGHT. FOG MAY BE A CONCERN IF SKIES CAN CLEAR...BUT
THINK DEVELOPMENT WILL BE LIMITED BY ABUNDANT CLOUD COVER.
LOWS TONIGHT WILL RANGE FROM THE LOWER 60S BEHIND THE FRONT TO THE
UPPER 60S ALONG AND SOUTH OF INTERSTATE 40.

WEDNESDAY...THINK RAIN COVERAGE/INTENSITY WILL BE MUCH LESS THAN
TODAY AND MAINLY CONFINED TO NORTH MISSISSIPPI AS THE COLD FRONT
CONTINUES MOVING SOUTH. SCALED BACK RAIN CHANCES IN MOST AREAS AS
LOW STRATUS CLOUDS BEHIND THE FRONT SHOULD KEEP THE AIR STABLE AND
LIMIT DEVELOPMENT OF SHOWERS AND STORMS...EXCEPT FOR PERHAPS NE MS
WHERE THE FRONT WILL BE SLOWER TO ARRIVE. A FEW STRONG STORMS WITH
HEAVY RAINFALL MAY OCCUR OVER NE MS...BUT THINK THE HEAVIEST STUFF
WILL BE FARTHER SOUTHEAST OVER CENTRAL ALABAMA. CLOUDS AND COOLER
AIR WILL KEEP TEMPERATURES DOWN AND MAINLY IN THE LOWER 80S.

WEDNESDAY NIGHT THROUGH FRIDAY...DRY CONDITIONS ARE FORECAST AS
HIGH PRESSURE BUILDS IN. TEMPERATURES WILL WARM BACK UP TO ABOVE
NORMAL VALUES BY FRIDAY WITH HIGHS NEAR 90. LOWS WILL MAINLY BE IN
THE 60S WITH HUMIDITY VALUES SLOWLY CLIMBING.

FRIDAY NIGHT THROUGH NEXT TUESDAY...LONG TERM MODELS ARE IN SOME
DISAGREEMENT WITH THE PLACEMENT OF FRONTS AND UPPER LEVEL RIDGES.
SEEMS LIKE THE ECMWF HAS BEEN MOST CONSISTENT...KEEPING THE UPPER
LEVEL RIDGE JUST WEST OF THE AREA. WITH THE DISCREPANCY IN THE
MODELS...KEPT THE PREVIOUS FORECAST OF LOW RAIN CHANCES AND ABOVE
NORMAL TEMPERATURES EACH DAY. THE SETUP OF NORTHWEST MID LEVEL
FLOW AND UNSTABLE AIR FROM SOUTHWEST LOW LEVEL WINDS MAY ALLOW
FOR MCS DEVELOPMENT...WHICH WOULD BRING POSSIBLE SEVERE WEATHER
AND HEAVY RAINFALL SOMETIME DURING THIS TIME FRAME.
TEMPERATURES APPEAR TO BE ON THE WARM SIDE AS WE ENTER JUNE
WITH HIGHS AROUND 90 AND LOWS IN THE 65 TO 70 DEGREE RANGE.

&&

.PRELIMINARY POINT TEMPS/POPS...
MEM  69  82  67  86 /  50  30  10  10
MKL  66  81  63  85 /  50  30  10   0
JBR  66  81  63  85 /  40  20  10   0
TUP  68  82  67  86 /  50  50  20  10

&&

.MEG WATCHES/WARNINGS/ADVISORIES...
AR...NONE.
MO...NONE.
MS...NONE.
TN...NONE.
&&

SJM/MBS

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE MEMPHIS TN
1010 PM CDT TUE MAY 27 2008

ARZ008-009-017-018-026>028-035-036-048-049-058-MOZ113-115-
MSZ001>017-020>024-TNZ001>004-019>021-048>055-088>092-282200-
ALCORN-BENTON MS-CALHOUN-CARROLL-CHESTER-CHICKASAW-CLAY-COAHOMA-
CRAIGHEAD-CRITTENDEN-CROCKETT-CROSS-DESOTO-DECATUR-DUNKLIN-DYER-
FAYETTE-GIBSON-GREENE-HARDEMAN-HARDIN-HAYWOOD-HENDERSON-HENRY-
ITAWAMBA-LAFAYETTE-LAKE-LAUDERDALE-LAWRENCE-LEE AR-LEE MS-MADISON-
MARSHALL-MCNAIRY-MISSISSIPPI-MONROE-OBION-PANOLA-PEMISCOT-
PHILLIPS-POINSETT-PONTOTOC-PRENTISS-QUITMAN-RANDOLPH-SHELBY-
ST. FRANCIS-TALLAHATCHIE-TATE-TIPPAH-TIPTON-TISHOMINGO-TUNICA-
UNION-WEAKLEY-YALOBUSHA-
1010 PM CDT TUE MAY 27 2008

THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF EAST ARKANSAS...
THE MISSOURI BOOTHEEL...NORTH MISSISSIPPI...AND WEST TENNESSEE.

.DAY ONE...TONIGHT

LOCALLY HEAVY RAINFALL MAY CAUSE ADDITIONAL FLASH FLOODING IN SOME
AREAS ACROSS THE MIDSOUTH OVERNIGHT. ONE TO TWO INCHES OF
RAINFALL MAY OCCUR IN SOME LOCATIONS IN AN HOUR OR LESS.

A FEW STRONG THUNDERSTORMS ARE POSSIBLE ACROSS THE ENTIRE MIDSOUTH
OVERNIGHT. THESE STORMS MAY CONTAIN WINDS UP TO 40 MPH AND SMALL
HAIL.

.DAYS TWO THROUGH SEVEN...WEDNESDAY THROUGH MONDAY

THE PROBABILITY FOR WIDESPREAD HAZARDOUS WEATHER IS LOW.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION IS NOT ANTICIPATED AT THIS TIME.

SJM

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE MEMPHIS TN
725 PM CDT TUE MAY 27 2008

MSZ001-TNZ088-280100-
DE SOTO MS-SHELBY TN-
725 PM CDT TUE MAY 27 2008

...THIS SIGNIFICANT WEATHER ALERT IS FOR...

  NORTHERN DESOTO COUNTY IN NORTHWEST MISSISSIPPI...
  SOUTHWESTERN SHELBY COUNTY IN SOUTHWEST TENNESSEE...

A STRONG THUNDERSTORM PRODUCING PEA TO DIME SIZE HAIL AND 40 TO 50
MPH WINDS WAS LOCATED OVER LYNCHBURG AT 725 PM CDT...MOVING NORTHEAST
AT 21 MPH.

VERY HEAVY RAIN ALONG WITH CONTINUOUS CLOUD TO GROUND LIGHTNING ARE
ALSO POSSIBLE WITH THIS THUNDERSTORM.

PEOPLE IN DESOTO AND SHELBY COUNTIES...INCLUDING THE CITIES OF HORN
LAKE...OLIVE BRANCH AND SOUTHAVEN...SHOULD MONITOR THIS STORM
CLOSELY. THIS SIGNIFICANT WEATHER ALERT IS IN EFFECT UNTIL 800 PM
CDT.