Severe Thunderstorm Warning 90, NWS Mobile, AL

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MOBILE AL
310 AM CST SAT APR 5 1997

MODELS SIMILAR IN MOVG UPPER LOW CURRENTLY JUST EAST OF THE ROCKY
MOUNTAINS TO THE NORTHEAST THROUGH FCST PERIOD. AT THE SFC...COLD
FRONT ACROSS PLAINS STATES PROGGED TO MOVE EAST ACROSS THE FCST AREA
OVER THE WEEKEND. THIS FRONT SHOULD WEAKEN AS IT MOVES ACROSS THE
AREA. IN ADVANCE OF THIS SYSTEM...STRONG SOUTHERLY WINDFLOW ADVECTING
GULF MOISTURE INTO THE REGION...WITH DEWPOINTS OVER THE AREA MAINLY
IN THE MIDDLE 60S. MODELS INDICATING ATMOSPHERE OVER FCST AREA
BECOMING MODERATELY UNSTABLE BY THIS AFTERNOON...WITH LI'S OF -2 OVER
MOST OF THE AREA...LI'S -4 JUST WEST OF THE AREA. SOMEWHAT FAVORABLE
VERTICAL WINDSHEAR OVER THE AREA TODAY BUT STRONGEST SHEARS NOTED
JUST WEST OF THE FCST AREA. MODELS INDICATE SQUALL LINE ASSOCIATED
WITH STORM SYSTEM TO MOVE ACROSS FCST AREA THIS AFTERNOON AND EARLY
EVENING....THIS CORRESPONDS TO MAXIMUM UVV'S OVER AREA. APPEARS ANY
SVR THREAT OVER COASTAL AREAS WILL BE LATE MORNING/EARLY AFTERNOON.
SVR THREAT WILL DIMINISH OVER THIS AREA BY EVENING AS STRONGEST
DYNAMICS LIFT NORTH OF THE AREA. FRONT PROGGED TO MOVE ACROSS FCST
AREA TONIGHT AND DURING THE DAY ON SUNDAY...AND SHOULD BE EAST OF THE
AREA BY AROUND 00Z MON. THINGS BEGIN TO DRY OUT LATE IN THE PERIOD.

MARINE WINDS WILL REMAIN IN THE 20-30 KNOT RANGE WITH SEAS UP TO 7 FT
TODAY AS TIGHT PRESSURE GRADIENT CONTINUES IN ADVANCE OF THE STORM
SYSTEMt. WINDS AND SEAS WILL BEGIN A GRADUAL DECREASE LATE TONIGHT AS
DYNAMICS ASSOCIATED WITH WEAKENING SYSTEM MOVE NORTH OF THE MARINE
AREA.

MOB 77/62/78/57 6321     PNS 76/67/79/60 5332
DTS 75/65/76/62 5332     EVR 79/61/79/55 5432 12

ALZ051>64-MSZ067-075-076-078-079-FLZ001>006-060600-

AREAL THUNDERSTORM OUTLOOK FOR
SOUTHWEST AL...NORTHWEST FL AND SOUTHEAST MS
NATIONAL WEATHER SERVICE MOBILE AL
1100 AM CST SAT APR 5 1997

...SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE NORTHERN GULF
STATES...

A PRE-FRONTAL SQUALL LINE OVER SOUTH MISSISSIPPI WILL CONTINUE TO
SPREAD TO THE EAST THROUGH SOUTHEAST MISSISSIPPI...MOVING INTO
SOUTHWEST ALABAMA AND NORTHWEST FLORIDA DURING THE AFTERNOON
EXTENDING INTO THE EVENING.

A VIGOROUS STORM SYSTEM OVER THE NATIONS MID SECTION IS PULLING A
WARM...MOIST...TROPICAL...UNSTABLE AIRMASS NORTHWARD ACROSS THE
REGION. THIS SYSTEM...IN COMBINATION WITH A PERSISTENT RIDGE OF HIGH
PRESSURE ACROSS THE EASTERN STATES...IS PROVIDING FOR BLUSTERY WINDS
FROM THE GROUND EXTENDING TO 7000 FEET HIGH IN THE ATMOSPHERE.
MORNING UPPER AIR SOUNDINGS AND WIND PROFILE DATA OFF THE WSR-88D
INDICATE FAVORABLE WIND DIRECTION CHANGE WITH HEIGHT AND ADEQUATE
ENERGY FOR DEEP AND PERSISTENT ROTATING THUNDERSTORM UPDRAFTS DURING
THE DAY.  WITH BETTER INSTABILITY DURING THE AFTERNOON HOURS...STORMS
THAT MOVE THROUGH THE REGION COULD BE SEVERE WITH THE POSSIBILITY OF
DAMAGING STRAIGHT LINE WINDS...TORNADOES AND HAIL.

AS A RESULT...THE STORM PREDICTION CENTER HAS PLACED THE NORTHERN
GULF STATES IN A SLIGHT RISK AREA FOR SEVERE THUNDERSTORMS.

BY EVENING...BETTER DYNAMICS FOR SEVERE STORMS WILL SHIFT FURTHER
NORTH AND EAST...OUT OF THE AREA SO A DECREASE IN THE SEVERE THREAT
WILL BE EXPECTED THEN...ALTHOUGH STORMINESS MAY LINGER WELL INTO THE
EVENING.

ACTIVATION OF SEVERE STORM SPOTTER NETWORKS AND EMERGENCY MANAGEMENT
PERSONNEL IN SOUTHEAST MISSISSIPPI AND SOUTHWEST ALABAMA WILL BE
REQUIRED THROUGH THE AFTERNOON AND POSSIBLY FOR NORTHWEST FLORIDA BY
MID AFTERNOON.

ALZ051>64-MSZ067-075-076-078-079-FLZ001>006-060600-

AREAL THUNDERSTORM OUTLOOK FOR
SOUTHWEST AL...NORTHWEST FL AND SOUTHEAST MS
NATIONAL WEATHER SERVICE MOBILE AL
1100 AM CST SAT APR 5 1997

...SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE NORTHERN GULF
STATES...

A PRE-FRONTAL SQUALL LINE OVER SOUTH MISSISSIPPI WILL CONTINUE TO
SPREAD TO THE EAST THROUGH SOUTHEAST MISSISSIPPI...MOVING INTO
SOUTHWEST ALABAMA AND NORTHWEST FLORIDA DURING THE AFTERNOON
EXTENDING INTO THE EVENING.

A VIGOROUS STORM SYSTEM OVER THE NATIONS MID SECTION IS PULLING A
WARM...MOIST...TROPICAL...UNSTABLE AIRMASS NORTHWARD ACROSS THE
REGION. THIS SYSTEM...IN COMBINATION WITH A PERSISTENT RIDGE OF HIGH
PRESSURE ACROSS THE EASTERN STATES...IS PROVIDING FOR BLUSTERY WINDS
FROM THE GROUND EXTENDING TO 7000 FEET HIGH IN THE ATMOSPHERE.
MORNING UPPER AIR SOUNDINGS AND WIND PROFILE DATA OFF THE WSR-88D
INDICATE FAVORABLE WIND DIRECTION CHANGE WITH HEIGHT AND ADEQUATE
ENERGY FOR DEEP AND PERSISTENT ROTATING THUNDERSTORM UPDRAFTS DURING
THE DAY.  WITH BETTER INSTABILITY DURING THE AFTERNOON HOURS...STORMS
THAT MOVE THROUGH THE REGION COULD BE SEVERE WITH THE POSSIBILITY OF
DAMAGING STRAIGHT LINE WINDS...TORNADOES AND HAIL.

AS A RESULT...THE STORM PREDICTION CENTER HAS PLACED THE NORTHERN
GULF STATES IN A SLIGHT RISK AREA FOR SEVERE THUNDERSTORMS.

BY EVENING...BETTER DYNAMICS FOR SEVERE STORMS WILL SHIFT FURTHER
NORTH AND EAST...OUT OF THE AREA SO A DECREASE IN THE SEVERE THREAT
WILL BE EXPECTED THEN...ALTHOUGH STORMINESS MAY LINGER WELL INTO THE
EVENING.

ACTIVATION OF SEVERE STORM SPOTTER NETWORKS AND EMERGENCY MANAGEMENT
PERSONNEL IN SOUTHEAST MISSISSIPPI AND SOUTHWEST ALABAMA WILL BE
REQUIRED THROUGH THE AFTERNOON AND POSSIBLY FOR NORTHWEST FLORIDA BY
MID AFTERNOON.