Concern For Tomorrow Grows...
04/09/2009 17:47
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PEACHTREE CITY GA
355 PM EDT THU APR 9 2009
.SHORT TERM /TONIGHT THROUGH SATURDAY NIGHT/...
PROGRESSIVE PATTERN WITH ACTIVE SOUTHERN STREAM TO CONTINUE THROUGH
NEXT WEEK. IMMEDIATE CONCERN IS CLOSED LOW LIFTING OUT OF THE SW
U.S. INTO THE CENTRAL PLAINS TONIGHT...THEN MOVING EAST TOWARD THE
MID-ATLANTIC BY FRIDAY NIGHT AND PHASING IN WITH THE EXISTING POLAR
VORTEX. THERE WILL BE TWO PHASES OF THIS SYSTEM TO AFFECT OUR CWA.
FIRST...AN AREA OF SHRA/TSRA CURRENTLY DEVELOPING ACROSS THE
ARKLATEX REGION WILL SPREAD INTO AL/GA LATE TONIGHT AND EARLY FRI.
ALTHOUGH THE SFC AIR MASS REMAINS RELATIVELY DRY AT THAT POINT WITH
DEWPOINTS 50 NORTH TO 58 SOUTH...HELICTY/SHEAR ARE QUITE IMPRESSIVE.
AN AXIS OF 400+ HELICITY AND -4 LIS APPROACH THE WESTERN BORDER OF GA
BY 12Z FRI. ECMWF/GFS/NAM ALL IN GOOD AGREEMENT THAT ONGOING
ACTIVITY ACROSS THE LOWER MS VALLEY/MID-SOUTH WILL INTENSIFY AND
SPREAD EASTWARD OVERNIGHT AND LIKELY TAKE ON THE FORM OF A SQUALL
LINE. THE POTENTIAL EXISTS FOR DAMAGING WINDS EARLY FRI IN NW/WC GA.
AS THIS ACTIVITY SPREADS EASTWARD ACROSS THE STATE DURING THE
MORNING...IT SHOULD DIMINISH. CLOUDS WILL LIKELY BREAK DURING THE
AFTERNOON BEHIND THIS INITIAL LINE OF CONVECTION LEAVING A
WARM...MOIST...UNSTABLE AIR MASS IN PLACE. AS THE UPPER TROUGH MOVES
INTO THE MID-ATLANTIC...A SECONDARY LOBE OF STRONG SHEAR/HELICITY
WILL TRACK ACROSS THE AREA. LIS DROP TO -6...CAPES GREATER THAN 1500
J/KG...AND THE EHI RISES TO AN IMPRESSIVE AND VERY CONCERNING 4.5
ACROSS N GA. DISCRETE SUPERCELL THUNDERSTORMS ARE LIKELY FRI
AFTN/EVE...WITH ALL FACETS OF SEVERE WEATHER POSSIBLE...INCLUDING
TORNADOES. SPC IS BORDERING ON A MODERATE RISK FOR OUR CWA...AND
LATER OUTLOOKS MAY WELL BE UPGRADED TO A MODERATE RISK AT LEAST FOR
A LARGE PORTION OF N GA FRI AFTERNOON. THIS SYSTEM PHASES/LIFTS OUT
OF THE AREA AROUND 06Z SAT AND THE THREAT FOR SEVERE WX ENDS QUICKLY
AT THAT TIME. SOME WRAP AROUND MOISTURE POSSIBLE IN THE NE MOUNTAINS
EARLY SAT...BUT WILL NOT ADVERTISE AT THIS TIME. SATURDAY LOOKS DRY
AND PLEASANT WITH A BRIEF BREAK BETWEEN SYSTEMS.
NATIONAL WEATHER SERVICE PEACHTREE CITY GA
355 PM EDT THU APR 9 2009
.SHORT TERM /TONIGHT THROUGH SATURDAY NIGHT/...
PROGRESSIVE PATTERN WITH ACTIVE SOUTHERN STREAM TO CONTINUE THROUGH
NEXT WEEK. IMMEDIATE CONCERN IS CLOSED LOW LIFTING OUT OF THE SW
U.S. INTO THE CENTRAL PLAINS TONIGHT...THEN MOVING EAST TOWARD THE
MID-ATLANTIC BY FRIDAY NIGHT AND PHASING IN WITH THE EXISTING POLAR
VORTEX. THERE WILL BE TWO PHASES OF THIS SYSTEM TO AFFECT OUR CWA.
FIRST...AN AREA OF SHRA/TSRA CURRENTLY DEVELOPING ACROSS THE
ARKLATEX REGION WILL SPREAD INTO AL/GA LATE TONIGHT AND EARLY FRI.
ALTHOUGH THE SFC AIR MASS REMAINS RELATIVELY DRY AT THAT POINT WITH
DEWPOINTS 50 NORTH TO 58 SOUTH...HELICTY/SHEAR ARE QUITE IMPRESSIVE.
AN AXIS OF 400+ HELICITY AND -4 LIS APPROACH THE WESTERN BORDER OF GA
BY 12Z FRI. ECMWF/GFS/NAM ALL IN GOOD AGREEMENT THAT ONGOING
ACTIVITY ACROSS THE LOWER MS VALLEY/MID-SOUTH WILL INTENSIFY AND
SPREAD EASTWARD OVERNIGHT AND LIKELY TAKE ON THE FORM OF A SQUALL
LINE. THE POTENTIAL EXISTS FOR DAMAGING WINDS EARLY FRI IN NW/WC GA.
AS THIS ACTIVITY SPREADS EASTWARD ACROSS THE STATE DURING THE
MORNING...IT SHOULD DIMINISH. CLOUDS WILL LIKELY BREAK DURING THE
AFTERNOON BEHIND THIS INITIAL LINE OF CONVECTION LEAVING A
WARM...MOIST...UNSTABLE AIR MASS IN PLACE. AS THE UPPER TROUGH MOVES
INTO THE MID-ATLANTIC...A SECONDARY LOBE OF STRONG SHEAR/HELICITY
WILL TRACK ACROSS THE AREA. LIS DROP TO -6...CAPES GREATER THAN 1500
J/KG...AND THE EHI RISES TO AN IMPRESSIVE AND VERY CONCERNING 4.5
ACROSS N GA. DISCRETE SUPERCELL THUNDERSTORMS ARE LIKELY FRI
AFTN/EVE...WITH ALL FACETS OF SEVERE WEATHER POSSIBLE...INCLUDING
TORNADOES. SPC IS BORDERING ON A MODERATE RISK FOR OUR CWA...AND
LATER OUTLOOKS MAY WELL BE UPGRADED TO A MODERATE RISK AT LEAST FOR
A LARGE PORTION OF N GA FRI AFTERNOON. THIS SYSTEM PHASES/LIFTS OUT
OF THE AREA AROUND 06Z SAT AND THE THREAT FOR SEVERE WX ENDS QUICKLY
AT THAT TIME. SOME WRAP AROUND MOISTURE POSSIBLE IN THE NE MOUNTAINS
EARLY SAT...BUT WILL NOT ADVERTISE AT THIS TIME. SATURDAY LOOKS DRY
AND PLEASANT WITH A BRIEF BREAK BETWEEN SYSTEMS.