Severe Thunderstorm Warning 110, NWS Memphis, TN

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MEMPHIS TN
943 AM CDT FRI MAY 8 2009

.DISCUSSION...

LARGE MCS IS APPROACHING THE NORTHERN PORTION OF THE FORECAST AREA
THIS MORNING. TORNADO WATCH NUMBER 267 IS NOW IN EFFECT FOR
ROUGHLY THE NORTHERN HALF OF THE FORECAST AREA. HAVE UPDATED
FORECAST TO INCLUDE TORNADO WATCH AND PUT MENTION OF POSSIBLE
SEVERE STORMS IN THE AREA UNDER THE WATCH. REMAINDER OF FORECAST
LOOKS FINE FOR NOW.

ARS

&&

.PREV DISCUSSION... /ISSUED 702 AM CDT FRI MAY 8 2009/

UPDATE...
UPDATED TO ADD 12Z AVIATION DISCUSSION.

PREV DISCUSSION... /ISSUED 425 AM CDT FRI MAY 8 2009/

DISCUSSION...
A WET WEEKEND APPEARS IN STORE THE MIDSOUTH AS THE FORECAST AREA
REMAINS IN CLOSE PROXIMITY TO STRONG WESTERLIES ALOFT AND A SURFACE
FRONT TO OUR NORTH... AND A HUMID UNSTABLE GULF AIRMASS TO THE
SOUTH.

THIS MORNING/S SAW A CLUSTER OF THUNDERSTORMS DROPPING
EAST/SOUTHEAST THROUGH MO...SOUTHERN IL AND WESTERN KY. ANOTHER
MCS WAS NOTED OVER CENTRAL KS. BOTH SYSTEMS WERE OCCURRING ALONG
THE PERIPHERY OF A BROAD...FLAT UPPER LEVEL RIDGE AND WERE FED BY
MOIST LOW LEVEL JETS. KTLX RADAR FROM CENTRAL OK SHOWED A 65KT
LOW LEVEL JET FEEDING INTO THE KS MCS. EXPECT SOME CONVECTIVELY
GENERATED BOUNDARIES TO ALREADY BE IN PLACE NORTH OF INTERSTATE 40
THIS AFTERNOON...SERVING AS A FOCUS FOR CONVECTION. WILL CARRY
HIGHEST POPS OVER THESE AREAS.

THE TREND THROUGH THE WEEKEND WILL BE A GRADUAL SUPPRESSION OF THE
SUBTROPICAL UPPER LEVEL RIDGE...A RESULT OF SHORTWAVE ENERGY...
SOME OF IT CONVECTIVELY ENHANCED...DIVING SOUTHEAST FROM THE
CENTRAL PLAINS. THE DIFFUSE SURFACE COLD FRONT THAT WAS OVER
SOUTHERN MO WILL DROP INTO THE MIDSOUTH LATE TONIGHT. ANY FLASH
FLOOD THREAT WILL LIKELY HOLD OFF UNTIL THIS MAIN FRONT DROPS INTO
THE MIDSOUTH. BY SATURDAY AFTERNOON... THE FRONT SHOULD DROP SOUTH
OF INTERSTATE 40...WITH BEST RAIN AND SEVERE THUNDERSTORM CHANCES
OVER EAST CENTRAL AR AND NORTH MS SATURDAY AFTERNOON.

SUNDAY AND MONDAY SHOULD SEE A COLD FRONT STALLING OUT SOUTH OF
THE FORECAST AREA...WITH COOLER AND MORE STABLE CONTINENTAL AIR
FILTERING INTO THE MIDSOUTH. THE MIDDLE PART OF THE WEEK WILL SEE
AN UPPER LEVEL RIDGE LIFT EAST FROM THE PLAINS INTO THE MS RIVER
VALLEY...WITH LOW LEVEL RETURN FLOW AND FEWER CLOUDS RESULTING IN
WARMER TEMPS TUESDAY AND WEDNESDAY. BOTH GFS AND ECMWF BRING A
COLD FRONT INTO THE MIDSOUTH THURSDAY AFTERNOON...WHICH WILL
REPRESENT THE NEXT APPRECIABLE RAIN CHANCE FOR THE MIDSOUTH.

PWB

AVIATION...
12Z TAFS

VFR CEILINGS EXPECTED TO CONTINUE TO FILL IN BETWEEN 12-14Z AS 850
MB LOW LEVEL JET CONTINUES TO TRANSPORT MOISTURE UP INTO THE LOWER
MISSISSIPPI VALLEY...PRODUCING MVFR CEILINGS THROUGH THE REMAINDER
OF THE 12Z TAF PERIOD. MESOSCALE CONVECTIVE SYSTEM OVER SOUTHWEST
MISSOURI EXPECTED TO DIVE SOUTHEAST INTO THE LOWER
MISSISSIPPI/TENNESSEE VALLEY TODAY PRODUCING SHOWERS AND
THUNDERSTORMS AT TAF SITES...ESPECIALLY JBR/MKL...AND MEM. TRIED
TO TIME BEST PROBABILITIES FOR THUNDERSTORMS WITH JBR BETWEEN
15-17Z...AND MEM/MKL BETWEEN 16-18Z. ADDITIONAL THUNDERSTORMS
EXPECTED LATER TONIGHT AS COLD FRONT DROPS SOUTH ACROSS TAF SITES.
WINDS WILL REMAIN PREDOMINANTLY FROM THE SOUTH AROUND 12-14KTS AND
VEERING NORTHWEST LATE TONIGHT AT JBR.

CJC

&&

.AVIATION...

&&

.PRELIMINARY POINT TEMPS/POPS...
MEM  86  66  72  56 /  40  60  60  50
MKL  85  64  70  56 /  70  60  60  40
JBR  81  62  69  55 /  70  70  50  40
TUP  89  67  80  60 /  30  40  50  40

&&

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

HAZARDOUS WEATHER OUTLOOK...CORRECTED
NATIONAL WEATHER SERVICE MEMPHIS TN
835 AM CDT FRI MAY 8 2009

ARZ008-009-017-018-026>028-035-036-048-049-058-MOZ113-115-
MSZ001>017-020>024-TNZ001>004-019>021-048>055-088>092-091100-
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-
835 AM CDT FRI MAY 8 2009

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

.DAY ONE...TODAY AND TONIGHT

THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER ALL OF THE
MIDSOUTH TODAY. THE PRIMARY SEVERE WEATHER THREATS WILL BE
DAMAGING WINDS AND LARGE HAIL. AN ISOLATED TORNADO OR TWO WILL
ALSO BE POSSIBLE.

A COLD FRONT OVER THE MIDDLE MISSISSIPPI RIVER VALLEY WILL MOVE
INTO THE MIDSOUTH TONIGHT...SERVING AS A FOCUS FOR CONTINUED
THUNDERSTORM DEVELOPMENT. SOME THUNDERSTORMS TONIGHT MAY REACH
SEVERE LIMITS.

.DAYS TWO THROUGH SEVEN...SATURDAY THROUGH THURSDAY

SATURDAY WILL SEE A SLIGHT RISK FOR SEVERE THUNDERSTORMS...MAINLY
SOUTH OF INTERSTATE 40.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION MAY BE REQUESTED OVER ANY PART OF THE MIDSOUTH
TODAY AND TONIGHT.