Severe Thunderstorm Warning 124, NWS Huntsville, AL

AREA FORECAST DISCUSSION...MESOSCALE UPDATE
NATIONAL WEATHER SERVICE HUNTSVILLE AL
1149 AM CDT TUE OCT 19 2004

.DISCUSSION...
WELL...MAIN FOCUS INITIALLY IS ON RAINFALL...AND SUBSEQUENT FLOODING
ALONG WITH THUNDER AND LIGHTNING. WE JUST ISSUED FLASH FLOOD
WARNINGS FOR LAUDERDALE AND COLBERT COUNTIES...AND HAVE A LIST OF AT
LEAST 10 COUNTY ROADS FLOODED IN LAUDERDALE AND A FEW ROADS IN
COLBERT COUNTY. LINCOLN COUNTY TN HAS MANY CREEKS AND STREAMS NEAR
BANKFULL AND WE WILL BE MONITORING THEM FOR POSSIBLE FFWS IN THE
NEXT FEW HOURS.

LATEST VISIBLE LOOP HAS BIG CLEARING AREA OVER ERN AR AND TO NEAR
OLIVE BRANCH MS. THE 1613Z MODIS PICTURE SHOWS THICK OVC CU/CB
AREA WITH BLOW OFF AC/CI WHICH MAY SAVE US FROM A WIDESPREAD SVR
EVENT. THIS CLEARING AREA ACROSS WRN TN AND NWRN MS...HAVE STARTED
THE AIRMASS RECOVERY OVER AR/MS/WRN TN. IT MAY ALSO HELP TO
DESTABILIZE THE 3 WESTERN COUNTIES...AND PERHAPS SOUTHERN LAWRENCE
COUNTY INTO CULLMAN COUNTY. OTHERWISE THE CLOUDS HAVE STABILIZED THE
BOUNDARY LAYER AND SURFACE TEMPS ARE ONLY IN THE MID 60S.

BIG SUPERCELL OVER UNION COUNTY MS...WILL BE MOVING INTO MORE STABLE
AIR AND MAY BECOME MORE OF A LINEAR STORM. MY SUPPORT FOR THIS IS THE
CAPES NEAR THAT STORM ARE 3000 J/KG WHILE WESTERN COLBERT HAS 300
J/KG. DEW POINTS ARE IN THE MID 70S IN NRN MS...WHILE WE HAVE MID 60S
ACROSS WRN AL.

OUR CURRENT THINKING IS THAT THUNDERSTORMS WILL EXPLODE OVER A 50
MILE AREA AROUND MEMPHIS AND FORM INTO A MCS AS IT MOVES EAST
DURING THE LATE AFTERNOON HOURS. THIS COULD BRING 1 TO 3 INCHES OF
ADDITIONAL RAINFALL.

THE LONG TERM FORECASTER WILL BE LOOKING AT THE POSSIBILITY OF A
FLOOD WATCH WITH THE 4 PM PACKAGE.

&&

.HUN WATCHES/WARNINGS/ADVISORIES...
AL...NONE.
TN...NONE.

&&

JDG

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE HUNTSVILLE AL
510 AM CDT TUE OCT 19 2004

ALZ001>010-016-TNZ076-096-097-191800-
COLBERT-CULLMAN-DE KALB-FRANKLIN AL-FRANKLIN TN-JACKSON-LAUDERDALE-
LAWRENCE-LIMESTONE-LINCOLN-MADISON-MARSHALL-MOORE-MORGAN-
510 AM CDT TUE OCT 19 2004

THIS HAZARDOUS WEATHER OUTLOOK IS FOR NORTH ALABAMA AND PARTS OF
SOUTHERN MIDDLE TENNESSEE.

.DAY ONE...(TODAY AND TONIGHT)...

FOR THE REST OF THIS MORNING...A LINE OF THUNDERSTORMS WILL CONTINUE
TO MOVE EAST ACROSS THE TENNESSEE VALLEY. IN STRONGER STORMS
EXPECT WIND GUSTS UP TO 40 MPH...FREQUENT LIGHTNING...PENNY SIZE HAIL
AND HEAVY RAIN WITH LOCALIZED FLOODING POSSIBLE.

FOR THIS AFTERNOON AND EARLY EVENING...WITH DAYTIME HEATING...
THUNDERSTORMS WILL LIKELY BECOME STRONG TO SEVERE WITH DAMAGING
WINDS OF 60 MPH...HAIL UP TO THE SIZE OF QUARTERS AND HEAVY RAIN.
THE BEST TIME FOR SEVERE WEATHER WILL BE FROM 1 PM TO 8 PM.

.DAYS TWO THROUGH SEVEN...(WEDNESDAY THROUGH MONDAY)...

THE PROBABILITY OF WIDESPREAD HAZARDOUS WEATHER IS LOW.

THERE IS A SLIGHT CHANCE OF SHOWERS AND THUNDERSTORMS ON WEDNESDAY
AND AGAIN ON SATURDAY AND SUNDAY.

.SPOTTER CALL TO ACTION STATEMENT...

ACTIVATION OF STORM SPOTTERS AND EMERGENCY MANAGEMENT PERSONNEL MAY
BE NECESSARY THIS AFTERNOON.

SS

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE HUNTSVILLE AL
842 AM CDT TUE OCT 19 2004

ALZ016-191430-
CULLMAN-
842 AM CDT TUE OCT 19 2004

...SIGNIFICANT WEATHER ALERT FOR LOCALLY HEAVY RAINFALL IN CULLMAN
COUNTY...

AT 842 AM...DOPPLER RADAR INDICATED THAT A LINE OF THUNDERSTORMS
CONTAINING VERY HEAVY RAINFALL STRETCHED FROM MARION COUNTY
ALABAMA...ALL THE WAY TO CHEROKEE COUNTY ALABAMA. THIS LINE WAS
BEGINNING TO MOVE IN MORE OF AN EASTERLY DIRECTION...PLACING CULLMAN
COUNTY IN A FAVORABLE LOCATION FOR PERSISTENT HEAVY RAINFALL THROUGH
930 AM.

CULLMAN COUNTY HAS ALREADY RECEIVED MORE THAN AN INCH AND A HALF OF
RAINFALL ACCORDING TO RADAR ESTIMATES. ADDITIONAL HEAVY RAINFALL MAY
CAUSE A RAPID RISE IN CREEKS...STREAMS...OR DRAINAGE DITCHES. PERSONS
ACROSS THE COUNTY ARE URGED TO KEEP AN EYE ON NEARBY LOW LYING
AREAS...AND BE PREPARED TO MOVE TO HIGHER GROUND IF NECESSARY.

STAY TUNED TO NOAA WEATHER RADIO...OR A FAVORITE MEDIA OUTLET...FOR
FURTHER STATEMENTS AND WARNINGS.

27

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE HUNTSVILLE AL
1021 AM CDT TUE OCT 19 2004

ALZ001>010-016-TNZ076-096-097-191700-
COLBERT-CULLMAN-DE KALB-FRANKLIN AL-FRANKLIN TN-JACKSON-LAUDERDALE-
LAWRENCE-LIMESTONE-LINCOLN-MADISON-MARSHALL-MOORE-MORGAN-
1021 AM CDT TUE OCT 19 2004

...SIGNIFICANT WEATHER ALERT FOR LOCALLY HEAVY RAINFALL AND THUNDER
ACROSS THE TENNESSEE VALLEY...

BANDS OF SHOWERS AND THUNDERSTORMS WILL CONTINUE TO FIRE UP ACROSS
THE VALLEY...AS A VERY UNSTABLE AIRMASS COLLIDES WITH A STATIONARY
FRONT JUST WEST OF THE MISSISSIPPI RIVER. RAINFALL AMOUNTS HAVE
AVERAGED 1 TO 2 INCHES SINCE MONDAY AFTERNOON...WITH UP TO 3 INCHES
IN A FEW SPOTS SUCH AS MERIDIANVILLE AND LYNCHBURG.

WE ARE EXPECTING SHOWER AND THUNDERSTORMS THROUGHOUT THE DAY...WITH
THE PRIMARY HAZARD BEING LOCALLY HEAVY RAIN AND LIGHTNING. WE
EXPECT ANOTHER INCH OF RAIN THROUGH THIS AFTERNOON...WITH SOME
LOCALITIES RECEIVING UP TO 2 INCHES TODAY.

ANY OUTDOOR ACTIVITY SHOULD BE CANCELED TODAY DUE TO LIGHTNING
AND RAIN. FOR TRAVELERS...PLEASE DRIVE AT A REDUCED SPEED. THE
COMBINATION OF MODERATE RAIN...AND WET LEAVES ON AREA ROADWAYS...WILL
CREATE A FAVORABLE ENVIRONMENT FOR HYDROPLANING. THERE HAVE BEEN
NUMEROUS ACCIDENTS THIS MORNING...DUE TO SPEED AND WET ROADS.

WE EXPECT MORE STORMS TO DEVELOP OVER EASTERN ARKANSAS...AND
NORTHWESTERN MISSISSIPPI THIS AFTERNOON...AND SOME OF THESE
STORMS COULD BECOME SEVERE LATER THIS AFTERNOON...PARTICULARLY AFTER
300 PM.

JDG

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE HUNTSVILLE AL
1200 PM CDT TUE OCT 19 2004

ALZ001>010-016-TNZ076-096-097-191900-
COLBERT-CULLMAN-DE KALB-FRANKLIN AL-FRANKLIN TN-JACKSON-LAUDERDALE-
LAWRENCE-LIMESTONE-LINCOLN-MADISON-MARSHALL-MOORE-MORGAN-
1200 PM CDT TUE OCT 19 2004

...SIGNIFICANT WEATHER ALERT FOR LOCALLY HEAVY RAINFALL AND THUNDER
ACROSS THE TENNESSEE VALLEY...

BREAKS IN THE CLOUDS OVER NORTHERN MISSISSIPPI AND WESTERN
TENNESSEE HAVE ALLOWED THE AIRMASS TO DESTABILIZE ONCE AGAIN LATE
THIS MORNING...WHICH HAS SPAWNED SEVERAL NEW BANDS OF SHOWERS AND
THUNDERSTORMS. RAINFALL THIS MORNING AVERAGED BETWEEN 1 AND 2
INCHES...WITH UP TO 3 INCHES IN SOME ISOLATED LOCATIONS.

SHOWERS AND THUNDERSTORMS WILL CONTINUE TO DEVELOP TO OUR WEST AND
MOVE EASTWARD. THE PRIMARY HAZARDS WITH THESE STORMS WILL BE
LOCALLY HEAVY RAIN...WITH AROUND AN INCH POSSIBLE...AND UP TO 2
INCHES LOCALLY. THESE STORMS MAY TRAIN OVER THE SAME AREAS...AND
WHEN COMBINED WITH EARLIER RAINFALL...FLASH FLOODING WILL AGAIN BE
A CONCERN THIS AFTERNOON. FREQUENT CLOUD TO GROUND LIGHTNING IS
ANOTHER CONCERN IN SOME OF THE STRONGER STORMS.

PERSONS ALL ACROSS THE TENNESSEE VALLEY SHOULD USE EXTREME CAUTION
TODAY. MOTORISTS ARE URGED TO DRIVE AT A REDUCED SPEED TO AVOID
HYDROPLANING AND A LOSS OF CONTROL ON WET ROADWAYS. IF A
THUNDERSTORM WITH FREQUENT LIGHTNING APPROACHES YOUR LOCATION...
AVOID USING ELECTRICAL DEVICES...STAY OFF THE TELEPHONE...AND STAY
AWAY FROM WINDOWS.

THERE IS THE POTENTIAL FOR ADDITIONAL STRONG TO SEVERE THUNDERSTORM
DEVELOPMENT THIS AFTERNOON...ESPECIALLY AFTER 3 PM. ANY STORMS
THAT DEVELOP MAY CONTAIN DAMAGING STRAIGHT LINE WINDS...WITH AN
ISOLATED TORNADO THREAT. STAY TUNED TO NOAA WEATHER RADIO...OR A
FAVORITE MEDIA OUTLET...FOR FURTHER STATEMENTS...WATCHES...OR
POTENTIAL WARNINGS.

BCC/JDG