Severe Thunderstorm Warning 154, NWS Tallahassee, FL

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TALLAHASSEE FL
215 PM EDT FRI AUG 16 2002

AS EXPECTED...WITH TODAYS SEA BREEZE REGIME ALONG WITH INHIBITED
INSOLATION DUE TO STRATUS OVER OUR EASTERN ZONES THIS MORNING...
LOCAL RADARS SHOW SHOWERS AND THUNDERSTORMS MORE ACTIVE ACROSS OUR
WESTERN ZONES. CURRENTLY (18Z) THERE IS NO ACTIVITY OVER OUR GA
ZONES AND NOTHING ACROSS FLORIDA EAST OF A LINE FROM QUINCY (GADSDEN
COUNTY TO CARRABELLE IN FRANKLIN COUNTY.

MODELS: MODELS IN GOOD AGREEMENT WITH HIGH PRESSURE ALOFT
BUILDING IN FROM THE EAST OVER OUR CWA. FORECAST SOUNDINGS AND
TIME-HEIGHT CROSS SECTIONS CLEARLY SHOW THE SUBSIDENCE DRYING IN THE
MID AND UPPER LEVELS. PWATS WILL DROP TO AROUND 1.8 INCH BY SATURDAY
AFTERNOON AND THEN DIP FURTHER INTO THE 1.7 - 1.5 INCH RANGE
SATURDAY NIGHT THROUGH MONDAY WITH MOST OF THE AVAILABLE MOISTURE
CONFINED BELOW 700MB. MOS REFLECTS THIS DRYING WITH POPS ACROSS THE
REGION GENERALLY IN THE 20 TO 40% RANGE. AT THE SURFACE...RIDGING
FROM THE WESTERN ATLANTIC HANGS ON THROUGH THE FORECAST PERIOD PUT
SLOWLY WEAKENS AS A COLD FRONT CURRENTLY OVER THE PACIFIC NORTHWEST
MOVES TO A POSITION FROM THE GREAT LAKES TO NORTHERN TEXAS BY SUNDAY
MORNING...THEN EXTENDS FROM THE MID ATLANTIC WESTWARD INTO A LOW
OVER THE OKLAHOMA PANHANDLE ON MONDAY.

ZFP: THE MEAN 100-700MB FLOW ON SATURDAY WILL BE SOUTH TO SOUTHEAST
10 KTS OR LESS...SAME AS TODAYS. THIS FAVORS HIGHER POPS OVER THE
WESTERN ZONES (40-60% WEST..10-30% EAST). ON SUNDAY THE FLOW WILL BE
W-SW 10 KNOTS OR LESS (REGIME 4) SHIFTING THE EMPHASIS TO OUR
EASTERN FLORIDA ZONES (40-50% AND 20-40% ELSEWHERE) THEN ON MONDAY
THE MEAN FLOW WILL BE LIGHT AND VARIABLE (REGIME 1) WITH FAIRLY
UNIFORM CHANCE POPS (30-40%) ACROSS OUR FLORIDA ZONES AND SLIGHT
CHANCE (10-20%) NORTH OF THE FLORIDA BORDER. DUE TO THE ABOVE
MENTIONED DISCUSSION...WILL UNDERCUT SEA BREEZE REGIME POPS AND STAY
CLOSE TO MOS.

MARINE: WINDS AND SEAS CONTINUE TO BE HIGHER OVER OUR OFFSHORE
WATERS AND WILL SPLIT OUT. OTHERWISE...WINDS AND SEAS SHOULD BE
FAIRLY UNIFORM ACROSS THE WATERS FOR THE REMAINDER OF THE FORECAST.
WINDS WILL VEER FROM THE SOUTHEAST ON SATURDAY TO THE SOUTHWEST
SUNDAY WITH SPEEDS INCREASING TO 10 TO 15 KNOTS LATE SUNDAY BEFORE
DIMINISHING TO 10 KNOTS OR LESS BY MONDAY MORNING. SEAS WILL BE 4
FEET OR LESS THROUGHOUT THE PERIOD.

FIRE WEATHER: NO CONCERNS.

EXTENDED (TUE-FRI): IN THE UPPER LEVELS...THE AVN SHOWS THE HIGH
OVER THE SOUTHEASTERN STATES THROUGH WEDNESDAY THEN RETROGRADES IT
TO OLD MEXICO BY FRIDAY WITH A TROUGH BEGINNING TO DIG OVER THE
EASTERN CONUS. AT THE SURFACE...THE WEAK FRONT ACROSS THE TENNESSEE
VALLEY ON TUESDAY GETS A NUDGE SOUTHWARD BY HIGH PRESSURE AHEAD OF A
STRONGER FRONT MOVING ACROSS THE NORTHERN PLAINS. THE MRF SHOWS THE
FRONT SAGGING SOUTH INTO MY CWA ON WEDNESDAY AND WASHES IT OUT BY
THURSDAY EVENING. HIGH PRESSURE RIDGES IN FROM THE EAST ON FRIDAY
WITH THE SECONDARY FRONT STAYING WELL NORTH OF THE LOCAL REGION. MEX
GUIDANCE SHOW POPS NEAR NORMAL WITH TEMPS SLIGHTLY ABOVE CLIMO.

PRELIM NUMBERS:
TLH 071/093 072/093 1213
PFN 076/090 076/090 2313
DHN 073/091 073/091 2313
ABY 073/093 073/092 1212
VLD 072/094 072/094 1212

.TLH...
.AL...NONE.
.GA...NONE.
.FL...NONE.

BARRY