Severe Thunderstorm Warning 148, NWS Huntsville, AL

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE HUNTSVILLE AL
1240 PM CDT THU MAY 26 2011

.UPDATE...18Z TAFS
&&

.AVIATION...BKN LINE OF TSTMS HAS PRETTY MUCH MOVED E OF BOTH TAF
SITES...WITH SCT/BKN MID/UPPER LEVEL CLOUD COVER BEGINNING TO MOVE
INTO THE WRN HALF OF THE AREA IN ASSOCIATION WITH THE ONCOMING UPPER
TROUGH. WEAK COLD FRONT IS ALSO BEGINNING TO PUSH EWD INTO NW AL
WHICH SHOULD HELP SUPPRESS MUCH IN THE WAY OF FURTHER CONVECTIVE
DEVELOPMENT. ONLY OTHER CONCERN IS SOME BR/LOW CEILINGS DEVELOPING
LATE TONIGHT WITH DIMINISHING WINDS. CONDITIONS SHOULD THEN IMPROVE
QUITE A BIT AFTER 14Z FRI AS A STRONG SFC HIGH BEGINS TO MOVE INTO
THE REGION...WITH VFR CONDITIONS PREVAILING ACROSS THE AREA.
&&

.DISCUSSION...SVR TSTM WATCH 379 HAS BEEN ISSUED FOR MOST OF N CNTRL
AND NE AL...ALONG WITH FRANKLIN CO TN. THE SVR WATCH IS IN EFFECT
THROUGH 5 PM...ALTHOUGH THE WATCH MAY BE ABLE TO BE CANCELLED EARLY
ONCE THE LINE CLEARS THE AREA TO THE E AND NO ADDITIONAL CONVECTION
DEVELOPS ALONG/AHEAD OF THE LINE. FORTUNATELY...THIS LINE DOES NOT
APPEAR QUITE AS STRONG AS THE EARLY MORNING SQ LINE. ALTHOUGH GIVEN
THE AMOUNT OF BULK SHEAR IN PLACE COUPLED WITH INCREASING SFC-BASED
INSTABILITY...AN ISOLATED TORNADO CAN NOT BE RULED OUT IN THE WATCH
AREA...ALTHOUGH THE PROB IS QUITE LOW. RAIN CHANCES WERE INCREASED
SLIGHTLY AS WELL IN THE WATCH AREA...WITH MOST/IF NOT ALL OF THE
CONVECTIVE ACTIVITY XPCTED TO MOVE OUT OF THE AREA THIS EVENING AS
THE COLD FRONT BEGINS TO ADVANCE EWD. NO OTHER CHANGES WERE MADE TO
THE ONGOING FORECAST AT THIS POINT.
&&

.PREVIOUS DISCUSSION...CURRENT WATER VAPOR SATELLITE IMAGERY
INDICATES THAT AN UPPER LOW OVER CENTRAL MISSOURI IS PROGRESSING
SLOWLY EASTWARD AND SHOULD CONTINUE TO FILL AS IT APPROACHES THE
MISSOURI-ILLINOIS BORDER LATER THIS MORNING. A WEAKENING SURFACE LOW
ASSOCIATED WITH THIS FEATURE WILL LIKEWISE LIFT NORTHEASTWARD ALONG
AND NORTH OF THE OHIO RIVER THROUGH THE MORNING. THE REMNANTS OF
NUMEROUS SHOWERS AND THUNDERSTORMS -- WHICH DEVELOPED YESTERDAY
ALONG A LOW-LEVEL TROUGH/CONFLUENCE AXIS EXTENDING SOUTHWARD FROM
THE SURFACE LOW --CONTINUE TO PROGRESS EASTWARD THROUGH THE LOWER
TENNESSEE VALLEY...WITH LINGERING SHOWERS/STORMS POSSIBLE FOR THE
REMAINDER OF THE MORNING. MODELS ARE IN GENERAL AGREEMENT THAT THE
MISSISSIPPI VALLEY UPPER LOW AND ASSOCIATED SURFACE CYCLONE WILL
BOTH CONTINUE TO WEAKEN AS THEY EJECT NORTHEASTWARD OVER THE OHIO
VALLEY AND TOWARD THE SOUTHEASTERN GREAT LAKES REGION THROUGHOUT THE
DAY TODAY. ANOTHER EPISODE OF CONVECTION IS EXPECTED TO DEVELOP AS
THE TRAILING SURFACE TROUGH AXIS ADVANCES EASTWARD ACROSS THE
REGION...WITH THIS MOST LIKELY TO OCCUR DURING THE AFTERNOON HOURS.
OVERALL...MODELS SUGGEST A LOWER AREAL COVERAGE OF THUNDERSTORMS
THIS AFTERNOON...WHICH SEEMS PLAUSIBLE AS EXTENSIVE CLOUDS AND
LINGERING OUTFLOW AIR FROM THE CURRENT PRECIPITATION SHOULD LIMIT
DESTABILIZATION TO SOME EXTENT...AND PWAT VALUES ARE ONLY FORECAST
TO RECOVER INTO THE 1.2-1.3 INCH RANGE. DESPITE THIS...POINT
FORECAST SOUNDINGS FROM THE NAM/GFS/UKMET/ECMWF ALL INDICATE STEEP
MID-LEVEL LAPSE RATES AND SOUTHWESTERLY UNIDIRECTIONAL WIND PROFILES
INCREASING TO 35-45 KNOTS ALOFT...WHICH WILL SUPPORT A THREAT FOR
LARGE HAIL AND DAMAGING WINDS WITH THE STRONGEST UPDRAFTS.

SCATTERED SHOWERS AND THUNDERSTORMS WILL LINGER INTO THE EARLY
EVENING HOURS ACROSS THE SOUTHEASTERN PORTION OF THE FORECAST
AREA...BUT THE GREATEST FOCUS FOR PRECIPITATION BEYOND THIS POINT
SHOULD SHIFT TO THE SOUTH AND EAST OF THE LOCAL AREA...AS THE LOW AND
MID-LEVEL TROUGHS DRIFT EASTWARD TOWARD THE SOUTHERN APPALACHIANS AND
BECOME MORE DIFFUSE. THE COMBINATION OF LIGHT NORTHWEST WINDS...
CLEARING SKIES...AND LINGERING BOUNDARY LAYER MOISTURE WILL LIKELY
RESULT IN AREAS OF MIST/FOG DEVELOPING OVERNIGHT. BY FRIDAY...WEAK
SHORTWAVE RIDGING ALOFT WILL BUILD OVER THE AREA DOWNSTREAM FROM AN
UPPER LOW SPREADING EAST-NORTHEASTWARD ACROSS THE NORTHERN PLAINS...
AND THIS WILL LEAD TO DRY WEATHER CONDITIONS. HIGH TEMPERATURES MAY
ACTUALLY BE A FEW DEGREES COOLER...IN REGIME DOMINATED BY MORNING
CLOUDS AND LIGHT NORTHWEST FLOW AS SURFACE RIDGE AXIS SHIFTS EASTWARD
ACROSS THE OHIO/TENNESSEE VALLEYS. MODELS INDICATE THAT THE MID-LEVEL
ANTICYCLONE WILL BECOME EVEN MORE ESTABLISHED FROM FRIDAY NIGHT INTO
SATURDAY NIGHT...AS ANOTHER UPPER LOW MOVES ONSHORE ALONG THE PACIFIC
COAST AND BEGINS TO DIG SOUTHEASTWARD OVER THE GREAT BASIN. THIS WILL
RESULT IN A CONTINUATION OF DRY WEATHER AND WARMER TEMPERATURES...
ESPECIALLY AS WINDS RETURN FROM THE SOUTHEAST IN RESPONSE TO A
DEEPENING LEE CYCLONE OVER THE SOUTHERN HIGH PLAINS.

A DRY AND VERY WARM WEATHER PATTERN STILL APPEARS TO BE IN STORE FOR
THE TENNESSEE VALLEY THROUGHOUT THE REMAINDER OF THE EXTENDED
FORECAST PERIOD...ALTHOUGH A SUBSTANTIAL AMOUNT OF UNCERTAINTY EXISTS
BETWEEN THE GFS/ECMWF REGARDING THE STRENGTH OF THE MID-LEVEL HIGH
OVER NORTHERN ALABAMA/SOUTHERN MIDDLE TENNESSEE. DURING THE PERIOD
FROM SUNDAY THROUGH WEDNESDAY...THE GFS MAINTAINS STRONGER MID-LEVEL
RIDGING OVER THE AREA...AS THE PREVIOUSLY MENTIONED GREAT BASIN UPPER
LOW BEGINS TO PIVOT NORTHEASTWARD ACROSS THE NORTHERN ROCKIES/PLAINS.
THE ECMWF...ON THE OTHER HAND...DEVELOPS A WEAK CUTOFF UPPER LOW OVER
FLORIDA AND ADJACENT PORTIONS OF THE EASTERN GULF...BEFORE
RETROGRADING THIS FEATURE TO THE SOUTHWEST. THE ONLY REAL EFFECT THAT
THIS FEATURE MAY HAVE IS TO INCREASE CLOUD COVER AND REDUCE HIGH
TEMPERATURES SOMEWHAT DURING THE UPCOMING WARM PERIOD...BUT WILL
GENERALLY NOT DEVIATE MUCH FROM MEXMOS TEMPERATURE GUIDANCE DURING
THE EXTENDED PERIOD. NEEDLESS TO SAY...RAIN CHANCES WILL BE VERY
LOW...AND MAY ONLY INCREASE SLIGHTLY WITH THE PASSAGE OF A WEAK COOL
FRONT LATE NEXT WEEK.
&&

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

UPDATE/AVIATION...09
PREV DISCUSSION...DD

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE HUNTSVILLE AL
105 PM CDT THU MAY 26 2011

ALZ001>010-016-TNZ076-096-097-270100-
LAUDERDALE-COLBERT-FRANKLIN AL-LAWRENCE-LIMESTONE-MADISON-MORGAN-
MARSHALL-JACKSON-DEKALB-CULLMAN-MOORE-LINCOLN-FRANKLIN TN-
105 PM CDT THU MAY 26 2011

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

.DAY ONE...THIS AFTERNOON AND TONIGHT...

SCATTERED TO BROKEN LINE OF STRONG TO SEVERE THUNDERSTORMS IS NOW
PRETTY MUCH FOCUSED ACROSS NORTHEAST ALABAMA...WITH THE WEAK COLD
FRONT BEGINNING TO MOVE EASTWARD INTO NORTHWEST ALABAMA. AS THE
FRONT CONTINUES EAST...CONVECTIVE ACTIVITY SHOULD BEGIN TO COME TO
AN END EARLY THIS EVENING. UNTIL THEN...THE PRIMARY WEATHER HAZARD
LOOKS TO BE MODERATE TO LARGE HAIL WITH ANY OF THE STRONGER TO
LOCALIZED SEVERE THUNDERSTORMS.

IN ADDITION TO THE THUNDERSTORM THREAT...PATCHY FOG DEVELOPMENT IS
POSSIBLE OVERNIGHT...WITH VISIBILITIES AND CLOUD HEIGHTS LOWERING
INTO THE EARLY MORNING HOURS FRIDAY.

.DAYS TWO THROUGH SEVEN...FRIDAY THROUGH WEDNESDAY...

NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME.

.SPOTTER CALL TO ACTION STATEMENT...

ACTIVATION OF STORM SPOTTERS AND EMERGENCY MANAGEMENT PERSONNEL IS
NOT ANTICIPATED AT THIS TIME.

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE HUNTSVILLE AL
1140 AM CDT THU MAY 26 2011

ALZ006-008-009-261730-
JACKSON-MADISON-MARSHALL-
1140 AM CDT THU MAY 26 2011

...SIGNIFICANT WEATHER ADVISORY FOR SOUTHWEST JACKSON...SOUTHEAST
MADISON AND MARSHALL COUNTIES UNTIL 1230 PM CDT...

AT 1139 AM CDT...NATIONAL WEATHER SERVICE DOPPLER RADAR WAS TRACKING
A STRONG THUNDERSTORM NEAR PAINT ROCK...OR 17 MILES SOUTHEAST OF
HUNTSVILLE...MOVING NORTHEAST AT 35 MPH.

PENNY SIZE HAIL...WINDS UP TO 40 MPH...FREQUENT CLOUD TO GROUND
LIGHTNING...AND HEAVY DOWNPOURS ARE EXPECTED WITH THIS STORM.

* LOCATIONS IN OR NEAR THE PATH INCLUDE...
  WOODVILLE.

A SEVERE THUNDERSTORM WATCH REMAINS IN EFFECT UNTIL 500 PM CDT
THURSDAY AFTERNOON FOR NORTHEASTERN ALABAMA AND CENTRAL TENNESSEE.

STAY TUNED TO NOAA WEATHER RADIO...COMMERCIAL RADIO...OR YOUR LOCAL
TELEVISION STATIONS FOR LATER STATEMENTS AND POSSIBLE WARNINGS
CONCERNING THIS WEATHER SITUATION.

&&

LAT...LON 3472 8628 3460 8616 3449 8637 3465 8648
TIME...MOT...LOC 1640Z 241DEG 30KT 3462 8632

SS

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE HUNTSVILLE AL
1154 AM CDT THU MAY 26 2011

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

1137 AM     HAIL             2 WNW NEW HOPE          34.55N 86.45W
05/26/2011  E0.75 INCH       MADISON            AL   CO-OP OBSERVER

&&

JS

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE HUNTSVILLE AL
1157 AM CDT THU MAY 26 2011

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

1146 AM     HAIL             2 W WOODVILLE           34.63N 86.31W
05/26/2011  E1.00 INCH       JACKSON            AL   PUBLIC

            COUNTY RD 5 AND HWY 72

&&

JS

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE HUNTSVILLE AL
1228 PM CDT THU MAY 26 2011

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

1219 PM     HAIL             SE SCOTTSBORO           34.67N 86.03W
05/26/2011  E1.00 INCH       JACKSON            AL   TRAINED SPOTTER

            AT SCOTT ST AND COLLEGE ST

&&

JS

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE HUNTSVILLE AL
102 PM CDT THU MAY 26 2011

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

1245 PM     HAIL             POWELL                  34.53N 85.90W
05/26/2011  E0.25 INCH       DEKALB             AL   EMERGENCY MNGR

&&

JS

PRELIMINARY LOCAL STORM REPORT...SUMMARY
NATIONAL WEATHER SERVICE HUNTSVILLE AL
106 PM CDT THU MAY 26 2011

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

1107 AM     HAIL             3 ESE HUNTSVILLE        34.72N 86.54W
05/26/2011  E0.50 INCH       MADISON            AL   TRAINED SPOTTER

1137 AM     HAIL             2 WNW NEW HOPE          34.55N 86.45W
05/26/2011  E0.75 INCH       MADISON            AL   CO-OP OBSERVER

1146 AM     HAIL             2 W WOODVILLE           34.63N 86.31W
05/26/2011  E1.00 INCH       JACKSON            AL   PUBLIC

            COUNTY RD 5 AND HWY 72

1219 PM     HAIL             SE SCOTTSBORO           34.67N 86.03W
05/26/2011  E1.00 INCH       JACKSON            AL   TRAINED SPOTTER

            AT SCOTT ST AND COLLEGE ST

1245 PM     HAIL             POWELL                  34.53N 85.90W
05/26/2011  E0.25 INCH       DEKALB             AL   EMERGENCY MNGR

&&

JS