Severe Thunderstorm Warning 178, NWS Huntsville, AL

308 
WWUS54 KHUN 310442
SVSHUN

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE HUNTSVILLE AL
1142 PM CDT MON JUL 30 2012

ALC033-059-310515-
/O.CON.KHUN.SV.W.0178.000000T0000Z-120731T0515Z/
COLBERT AL-FRANKLIN AL-
1142 PM CDT MON JUL 30 2012

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 1215 AM CDT
FOR FRANKLIN AND SOUTHWESTERN COLBERT COUNTIES...

AT 1136 PM CDT...NATIONAL WEATHER SERVICE DOPPLER RADAR CONTINUED TO
INDICATE A SEVERE THUNDERSTORM CAPABLE OF PRODUCING DESTRUCTIVE WINDS
IN EXCESS OF 70 MPH.  THIS STORM WAS LOCATED NEAR MYNOT...OR ABOUT 14
MILES NORTHEAST OF RED BAY...MOVING SOUTHEAST AT 35 MPH.

OTHER LOCATIONS IN THE WARNING INCLUDE BUT ARE NOT LIMITED TO POSEY
LOOP...SRYGLEY CHURCH...NEW BETHEL...DEMPSEY...CROOKED OAK...COLBERT
HEIGHTS...BELGREEN...LITTLEVILLE...RUSSELLVILLE...ROCKWOOD...
ISBELL...PLEASANT RIDGE...DUKETON...THARPTOWN AND LA GRANGE

PRECAUTIONARY/PREPAREDNESS ACTIONS...

THIS STORM HAS A HISTORY OF PRODUCING WIDESPREAD WIND DAMAGE ACROSS 
PARTS OF ALCORN COUNTY MISSISSIPPI. THIS IS AN EXTREMELY DANGEROUS 
SITUATION. SEEK SHELTER NOW INSIDE A STURDY STRUCTURE AND STAY AWAY 
FROM WINDOWS!

&&

LAT...LON 3461 8813 3486 8809 3476 8785 3474 8784
      3473 8779 3461 8750 3430 8785 3431 8790
TIME...MOT...LOC 0440Z 313DEG 30KT 3458 8798

$$

867 
WWUS54 KHUN 310458
SVSHUN

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE HUNTSVILLE AL
1158 PM CDT MON JUL 30 2012

ALC033-059-310515-
/O.CON.KHUN.SV.W.0178.000000T0000Z-120731T0515Z/
COLBERT AL-FRANKLIN AL-
1158 PM CDT MON JUL 30 2012

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 1215 AM CDT
FOR FRANKLIN AND SOUTHWESTERN COLBERT COUNTIES...

AT 1154 PM CDT...NATIONAL WEATHER SERVICE DOPPLER RADAR CONTINUED TO
INDICATE A SEVERE THUNDERSTORM CAPABLE OF PRODUCING DESTRUCTIVE WINDS
IN EXCESS OF 70 MPH.  THIS STORM WAS LOCATED NEAR BELGREEN...OR ABOUT
8 MILES WEST OF RUSSELLVILLE...MOVING SOUTHEAST AT 35 MPH.

OTHER LOCATIONS IN THE WARNING INCLUDE BUT ARE NOT LIMITED TO
LITTLEVILLE...ROCKWOOD...ISBELL...PLEASANT RIDGE...DUKETON AND
THARPTOWN

PRECAUTIONARY/PREPAREDNESS ACTIONS...

THIS IS A DANGEROUS STORM. IF YOU ARE IN ITS PATH...PREPARE 
IMMEDIATELY FOR DAMAGING WINDS AND DEADLY CLOUD TO GROUND LIGHTNING. 
PEOPLE OUTSIDE SHOULD MOVE TO A SHELTER...PREFERABLY INSIDE A STRONG 
BUILDING BUT AWAY FROM WINDOWS.

&&

LAT...LON 3461 8813 3479 8809 3475 8796 3471 8787
      3465 8775 3457 8756 3430 8785 3431 8790
TIME...MOT...LOC 0458Z 313DEG 30KT 3448 8785

$$

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HUNTSVILLE AL
907 PM CDT MON JUL 30 2012

.UPDATE...
NO CHANGES TO FCST ATTM.

&&

.DISCUSSION...
AT THE SFC A LOW PRESSURE AREA WAS OVER NRN AR WITH A FRONTAL
BOUNDARY EXTENDING FROM SRN KS TO NRN AL. AT 5H...A LARGE RIDGE
CONTINUES OVER THE SWRN US...PROVIDING TRICKY NW FLOW ACROSS THE
SERN US. THE COMBINATION OF THE EASTWARD MOVING SFC LOW ALONG THE SFC
BOUNDARY...AN UPPER DISTURBANCE AND 8H WINDS BETWEEN 20 TO 30
KT...WILL INCREASE THE COVERAGE OF SHRA/TSRA ACROSS THE CWA BEGINNING
ARND MIDNIGHT OVER NW AL. SOME STORMS OVERNIGHT COULD BECOME STRONG
TO SVR WITH DAMAGING WINDS THE MAIN THREAT. HAIL UP TO THE SIZE OF
QUARTERS AND HVY RAIN WILL ALSO BE POSSIBLE. ONE FACTOR THAT MAY
LIMIT THE COVERAGE OF STORMS ACROSS THE TN VALLEY WOULD BE A FAIRLY
DRY LAYER FROM 8H TO THE SFC.

07

&&

.AVIATION...
/ISSUED 654 PM CDT MON JUL 30 2012/
FOR 00Z TAFS...CENTER OF UPPER HIGH IS OVER TX WHICH IS PUTTING OUR
CWA IN NW FLOW. STLT/RADARS ARE SHOWING AN AREA OF CONVECTION
DEVELOPING OVER NE AR. ATTM THE UPPER FLOW PATTERN WOULD KEEP THIS
AREA OF CONVECTION TO THE WEST OF THE TN VALLEY. THERE IS ALSO A
LARGE BAND OF MAINLY SHRA ACTIVITY ACROSS PORTIONS OF MO/SRN IL AND
WRN KY. BASED ON STLT/RADAR TRENDS ITS BEGINNING TO LOOK LIKE THE
THREAT OF STRONGER STORMS MAY BE WEST OF THE TAF SITES WITH OUR CWA
RECEIVING MOSTLY SHRA. NAM TIME SECTIONS WERE SHOWING A FAIRLY DRY
LAYER FROM 8H DOWN TO THE SFC...SUGGESTING MORE OF AN ELEVATED TSRA
THREAT FOR OUR CWA. FOR NOW WILL PUT VCSH IN MAIN BODY OF TAFS FROM
06Z TO ARND 16Z. WILL GO WITH A TEMPO GROUP FOR TSRA BETWEEN 06Z AND
10Z TONIGHT. VFR CONDITIONS ARE EXPECTED FOR TAFS...EXCEPT DURING
TSRA WHERE MVFR MAY OCCUR.

07

&&

.PREV DISCUSSION...
/ISSUED 309 PM CDT MON JUL 30 2012/
SEVERAL SHORTWAVE TROUGHS CONTINUE TO MARCH ACROSS THE NORTHERN
PORTIONS OF NORTH AMERICA WITH SEVERAL MID-UPPER SHORTWAVE TROUGHS
OFF THE COAST OF ALASKA TOWARDS THE CANADA/U.S. BORDER. MEANWHILE,
SEVERAL SHORTWAVE TROUGHS/EDDIES ARE CONTINUING TO ROUND THE
ENTRENCHED RIDGE OVER TX.

A SHORTWAVE TROUGH ROUNDING THE EASTERN FRINGES OF AN ENTRENCHED
RIDGE OF HIGH PRESSURE IS BRINGING SHOWERS ALONG WITH MID TO HIGH
LEVEL CLOUDS ACROSS THE TN VALLEY. WEAK SFC CYCLOGENESIS ALONG WITH
A 35-40 KTS. 850 HPA JET INDUCED FROM THIS TROUGH OVER SOUTHERN MO
WILL BE BRINGING INCREASED WIND SHEAR THIS EVENING AND DURING THE
OVERNIGHT. THIS WIND SHEAR COMBINED WITH THE MODERATE TO HIGH
INSTABILITY, IS EXPECTED TO RESULT IN THE DEVELOPMENT OF STRONG TO
POSSIBLY SEVERE THUNDERSTORMS, INITIALLY OVER NW AL. HOWEVER, AS THE
INDUCED WEAK SFC LOW/THERMAL BOUNDARY APPROACHES FROM THE NW
OVERNIGHT, AN ENHANCED LLJ DEPICTED BY THE NAM APPEARS TO RESULT IN
WEAKER THUNDERSTORMS DUE TO ITS ADVECTION OF WARM/DRY AIR. NOT
EXACTLY SURE WHETHER TO BELIEVE THIS SOLUTION AT THIS TIME. STORM
MODE, BASED ON THE SHEAR PROFILE, APPEARS TO BE CELLULAR, BUT COULD
TRANSITION TO MULTI-CELLULAR AT TIMES. THE MAIN THREATS APPEAR TO BE
DAMAGING WINDS AND HEAVY RAINFALL. HOWEVER, THERE IS A SECONDARY
THREAT WITH ANY OF THE STORMS WITH STRONGER UPDRAFTS THAT MAY PRODUCE
LARGE HAIL. HAVE RAISED POPS TONIGHT GIVEN THE MODEL SOLUTION
CONVERGENCE.

CONVECTIVE ACTIVITY WILL LIKELY BE ONGOING ACROSS THE AREA DURING
THE MORNING TOMORROW AND MAY CONTINUE THROUGH THE REST OF THE
AFTERNOON AND EVENING ON TUESDAY. INSTABILITY DOES LOOK TO WEAKEN
CONSIDERABLY BEHIND THE PASSAGE OF THE SHORTWAVE TROUGH LATER
TOMORROW MORNING. SO, LATER SHIFTS MAY NEED TO TAPER POPS TOMORROW
AS STORMS WEAKEN/DISSIPATE. HOWEVER, STRONG TO SEVERE THUNDERSTORMS
STILL LOOK POSSIBLE, ESPECIALLY SOUTH OF THE TN RIVER AND OVER NE AL
AS DAYTIME HEATING INCREASES INSTABILITY (MAINLY FOR A BRIEF TIME
PERIOD BTWN 15-18Z). DAYTIME HIGHS ARE FORECAST TO SOAR INTO THE MID
TO POSSIBLY UPPER 90S, BUT HAVE HELD BELOW METMOS GUIDANCE AS IT
APPEARS TO BE OVERDONE. HAVE ALSO INCLUDED SOMEWHAT DRIER AIR WHICH
HAS TRANSLATED TO HEAT INDEX VALUES AROUND 100 DEGREES.

ONCE THIS SHORTWAVE CLEARS, CONVECTIVE ACTIVITY SHOULD WEAKEN AND
DISSIPATE TOMORROW EVENING INTO THE OVERNIGHT PERIOD. THERE IS A
THREAT FOR PATCHY FOG, BUT HAVE NOT INCLUDED IN THE FORECAST YET,
GIVEN THE LIKELIHOOD OF LINGERING CONVECTIVE ANVIL DEBRIS CLOUDS. BY
WEDNESDAY, MORE DIURNALLY DRIVEN ISOLATED AFTERNOON THUNDERSTORMS
WILL BE THE MAIN THREAT DURING THE AFTERNOON HOURS.

ON WEDNESDAY EVENING INTO LATE WEDNESDAY NIGHT, AN ADDITIONAL WEAK
SHORTWAVE CROSSES THE MO VALLEY INTO W TN/N MS. IT DOES APPEAR THAT
ADDITIONAL THUNDERSTORMS MAY BE POSSIBLE OVER NW AL AND EXTENDING
INTO THE CENTRAL PORTIONS OF MS BY EARLY THURSDAY MORNING. YET
ANOTHER SHORTWAVE TROUGH APPEARS TO CROSS THE REGION ON THURSDAY
AFTERNOON AND EVENING. NOW THIS SOLUTION OF THE LAST SHORTWAVE ON
THURSDAY IS MAINLY DEPICTED BY THE GFS. GIVEN THE UNCERTAINTY WITH
THIS SOLUTION WILL JUST KEEP CHC OF THUNDERSTORMS FOR NOW.

THE REST OF THE EXTENDED FORECAST MAINLY INVOLVES A TRANSITION FROM
A TROUGH TO A MORE RIDGE-LIKE PATTERN BY THE EARLY PART OF NEXT WEEK.
THIS WILL MEAN THAT THE WEEKEND FORECAST WILL MAINLY CONCERN
DIURNALLY DRIVEN AFTERNOON CONVECTION WITH VERY HOT CONDITIONS (UPPER
90S) POSSIBLE DURING THE AFTERNOON HOURS.

SL.77

&&

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

FOR MORE INFORMATION PLEASE VISIT OUR WEBSITE
AT WEATHER.GOV/HUNTSVILLE.

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE HUNTSVILLE AL
817 PM CDT MON JUL 30 2012

ALZ001>010-016-TNZ076-096-097-311000-
LAUDERDALE-COLBERT-FRANKLIN AL-LAWRENCE-LIMESTONE-MADISON-MORGAN-
MARSHALL-JACKSON-DEKALB-CULLMAN-MOORE-LINCOLN-FRANKLIN TN-
817 PM CDT MON JUL 30 2012

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

.DAY ONE...TONIGHT...

THUNDERSTORMS WILL BECOME MORE NUMEROUS TONIGHT BEGINNING AROUND
MIDNIGHT AS A STRONG DISTURBANCE CROSSES THE REGION. SOME STRONG TO
SEVERE THUNDERSTORMS WILL BE POSSIBLE...WITH DAMAGING STRAIGHT LINE
WINDS...HAIL UP TO THE SIZE OF QUARTERS AND LOCALLY HEAVY DOWNPOURS.

.DAYS TWO THROUGH SEVEN...TUESDAY THROUGH SUNDAY...

STRONG TO SEVERE THUNDERSTORMS WITH GUSTY STRAIGHT LINE WINDS MAY
LINGER INTO TUESDAY...AS THE DISTURBANCE SLOWLY EXITS TO THE
SOUTHEAST.

TYPICAL MAINLY DAYTIME SHOWERS AND THUNDERSTORMS WILL RETURN ON
WEDNESDAY...CONTINUING INTO THE WEEKEND. GUSTY WINDS WILL BE THE MAIN
THREATS.

.SPOTTER CALL TO ACTION STATEMENT...

ACTIVATION OF STORM SPOTTERS AND EMERGENCY MANAGEMENT PERSONNEL MAY
BE POSSIBLE LATE TONIGHT THROUGH EARLY TUESDAY MORNING.