Severe Thunderstorm Warning 142, NWS Jacksonville, FL

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JACKSONVILLE FL
225 PM EDT TUE JUN 27 2000

SFC ANALYSIS SHOWS RIDGE OF HIGH PRES OVER NORTH FL AND SE GA. W AND
E COAST SEA BREEZES ACTIVE WITH CONVECTION FIRING ALONG THE BOUNDARY
FROM FLAGLER COUNTY NWD TO NASSAU. MORE IMPORTANTLY...AN OUTFLOW
BOUNDARY NOTED IN VIS IMAGERY COMING UP FROM SSE TRIGGERING
ADDITIONAL CONVECTION OVER MARION...PUTNAM...AND FLAGLER. WATER
VAPOR IMAGERY INDICATES THE SHEAR AXIS ALOFT FROM SC TO SE GA AND
THE NE GULF OF MEXICO CONTINUES TO ENHANCE DIFLUENCE OVER THE CWA.

FORECAST...MODELS IN GOOD AGREEMENT AT 500 MB SHOWING THE SHEAR AXIS
OVER THE REGION WEAKENING WITH THE AVN STRONGER WITH AXIS DURING THE
PD. MEANWHILE...SHORTWAVE ENERGY CONTINUES DROPPING INTO THE EASTERN
U.S. TROUGH. THIS TRANSLATES INTO 5H HEIGHTS LOWERING 10-20 M OVER N
FL AND SE GA. MOISTURE PROGS FROM MODELS INDICATE LITTLE CHANGE
DURING THE PD EXCEPT FOR A LITTLE DRYING IN THE MID TO UPPER LEVELS
EARLY WED AFTN THEN INCREASING A LITTLE AGAIN ON THU. WITH MODELS
TENDING TO DRY OUT THE MID LEVELS AND THE SHEAR AXIS WEAKENING
...WILL CONTINUE TREND OF A SLIGHT DECREASE IN POPS. THEREFORE LIKE
THE LOWER NGM POPS OVER FAN GUIDANCE. WEAK 10 KT SLY FLOW OVER LAND
WILL ALLOW SEA BREEZES TO BECOME ACTIVE ON WED WITH BEST RAIN
CHANCES INLAND. ON THU...SHORTWAVE WILL MOVE INTO THE SE STATES WILL
DEVELOP SFC LOW OVER N GA/WRN SC/ERN TN WITH ASSOCIATED FRONTAL
BOUNDARY MOVING INTO N AL. TEND TO DISAGREE WITH AVN/S AGGRESSIVE
SFC LOW OVER AL BY 18Z THU. SFC RIDGE WILL BEGIN DROPPING INTO S FL
BY THAT TIME WITH SFC FLOW OVER CWA BECOMING MORE SWLY. ETA ALSO
SHOWS SHORTWAVE MOVING INTO THE BIG BEND AREA BY 18Z THU WITH OMEGA
FIELD AIDING DAYTIME HEATING SO WILL GO WITH GOOD CHANCE INLAND AND
CHANCE AT THE COAST. GUIDANCE TEMPS LOOK SIMILAR AND WILL ADJUST
WITH PERSISTENCE.

MARINE...WINDS TO STAY MAINLY SLY DURING THE PD AT 10-15 KT.
INCREASING SLY FLOW ON WED NIGHT AND WILL GO WITH 15 KT FOR NOW.
NO HIGHLIGHTS THIS PACKAGE.

EXTENDED...NEW AVN RUN SHOWS LESS AMPLITUDE TO THE 5H TROUGH OVER
THE EAST THAN THE 00Z MRF. THE UKMET ALSO IN SIMILAR AGREEMENT TO THE
LATEST AVN RUN. THIS SHOULD SLOW OR HALT SWD MOVEMENT OF THE FRONT.
THEREFORE PREFER TO LEAVE A CHANCE OF SHOWERS AND THUNDERSTORMS
FRI-SUN AT LEAST FOR N FL.

PRELIM
AMG 70/89/71/90 2525
SSI 74/88/74/89 3524
JAX 71/960/71/91 3524
GNV 70/90/69/90 3625 02

.JAX...
.GA...NONE
.FL...NONE

ARS

FLZ020>025-030>033-035>038-040-GAZ132>136-149>154-162>166-272200-

NORTHEAST FLORIDA/SOUTHEAST GEORGIA HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE JACKSONVILLE FL
1252 PM EDT TUE JUN 27 2000

A WEAK UPPER LEVEL LOW OVER SOUTHEASTERN GEORGIA WILL ENHANCE
SCATTERED TO NUMEROUS THUNDERSTORMS ACROSS THE AREA THIS AFTERNOON.
A LINE OF STORMS OVER CENTRAL FLORIDA IS MOVING NORTHWARD INTO A
VERY UNSTABLE AIR MASS.  A FEW STORMS COULD BECOME SEVERE WITH
DAMAGING WIND GUSTS AND HAIL. LOCAL RAINFALL AMOUNTS OF 2 TO 3 INCHES
MAY BE EXPECTED.

STORM SPOTTERS SHOULD BE ALERT FOR POSSIBLE ACTIVATION.

FOR ADDITIONAL INFORMATION...VISIT THE NATIONAL WEATHER SERVICE IN
JACKSONVILLE WEBSITE ON THE INTERNET AT WWW.NWSJAX.NOAA.GOV.

TRABERT