000
AXNT20 KNHC 272336
TWDAT 

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
705 PM EST WED FEB 27 2013

TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL 
AMERICA...GULF OF MEXICO...CARIBBEAN SEA...NORTHERN SECTIONS OF 
SOUTH AMERICA...AND ATLANTIC OCEAN TO THE AFRICAN COAST FROM THE 
EQUATOR TO 32N. THE FOLLOWING INFORMATION IS BASED ON SATELLITE 
IMAGERY...WEATHER OBSERVATIONS...RADAR...AND METEOROLOGICAL 
ANALYSIS.

BASED ON 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
2245 UTC.

...ITCZ/MONSOON TROUGH...

THE MONSOON TROUGH EXTENDS SOUTHERN LIBERIA NEAR 5N8W TO 1N12W 
WHERE IT TRANSITIONS INTO ITCZ AND CONTINUES ALONG EQ30W 4S45W. 
SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS FROM 4N-5N 
BETWEEN 11W-14W...FROM 1N-3N BETWEEN 14W-22W...AND FROM 1N-2N 
BETWEEN 30W-35W. 

...DISCUSSION...

GULF OF MEXICO...
A DEEP-LAYERED LOW REMAINS OVER THE EASTERN CONUS CENTERED NEAR 
THE GREAT LAKES REGION. THE UPPER LOW CONTINUES TO SUPPORT A 
PAIR OF FRONTS ACROSS THE GULF OF MEXICO. THE FIRST FRONT 
REMAINS STATIONARY EXTENDING FROM THE FLORIDA KEYS NEAR 25N81W 
TO THE YUCATAN PENINSULA ALONG 22N86W 18N88W. OVERCAST SKIES AND 
SCATTERED LIGHT SHOWERS EXTEND UP TO 130 NM NORTH AND WEST OF 
THE FRONT. THE SECOND FRONT IS JUST BEGINNING TO MOVE INTO THE 
NW CORNER OF THE GULF AS A COLD FRONT EXTENDING FROM NEAR 29N95W 
TO 26N98W. THE SECOND FRONT HAS NO PRECIPITATION ASSOCIATED WITH 
IT AND HAS AN AIRMASS WITH LOWER DEWPOINTS BEHIND IT. BETWEEN 
THE TWO FRONTS...A WEAK SURFACE RIDGE REMAINS AROUND A 1018 MB 
HIGH NEAR 27N93W. THE RIDGE WILL DISSIPATE AS THE SECOND FRONT 
MOVES FARTHER EAST. LIGHT ANTI-CYCLONIC WINDS ARE CURRENTLY 
AROUND THE RIDGE AND BETWEEN THE TWO FRONTS. STRONGER WINDS WILL 
BE PRESENT BEHIND THE SECOND FRONT AS IT MOVES EAST. CURRENTLY 
WINDS ARE OBSERVED UP TO 20 KT BEHIND THAT FRONT. ALOFT...MAINLY 
ZONAL WESTERLY FLOW COVERS THE BASIN AROUND THE BASE OF THE DEEP 
UPPER LOW TO THE NORTH. 

CARIBBEAN SEA...
MOSTLY FAIR WEATHER AND CLEAR SKIES ARE ACROSS THE CARIBBEAN DUE 
TO DRY AIR ALOFT AROUND A BROAD UPPER RIDGE COVERING THE BASIN. 
WATER VAPOR IMAGERY ALSO INDICATES THAT STRONG SUBSIDENCE IS 
OVER THE EASTERN CARIBBEAN. TRADEWIND FLOW OF 15-20 KT IS 
PRESENT ACROSS THE MAJORITY OF THE AREA WITH ONLY A FEW POSSIBLE 
ISOLATED SHOWERS EMBEDDED WITHIN THE FLOW. A STATIONARY FRONT 
LIES JUST ALONG THE NW BORDER OF THE BASIN FROM NORTH OF CUBA TO 
THE YUCATAN PENINSULA. IT WILL REMAIN STATIONARY UNTIL A SECOND 
FRONT CATCHES UP AND MERGES WITH IT AND THEN MOVES INTO THE 
BASIN ON FRIDAY AND THROUGH THE WEEKEND. LITTLE CHANGE IS 
EXPECTED UNTIL THEN. 

ATLANTIC OCEAN...
THE COLD FRONT ASSOCIATED WITH THE DEEP LAYERED LOW OVER THE 
EASTERN CONUS ENTERS THE WEST ATLC NEAR 32N72W AND CONTINUES TO 
THE BAHAMAS NEAR 27N77W BEFORE BECOMING STATIONARY TO THE 
FLORIDA KEYS AND INTO THE EXTREME SE GULF. SCATTERED 
SHOWERS/ISOLATED THUNDERSTORMS EXTEND UP TO 160 NM EAST OF THE 
AXIS WITH ISOLATED SHOWERS UP TO 140 NM WEST OF THE AXIS. AN 
UPPER LEVEL RIDGE COVERS THE MAJORITY OF THE WEST ATLC 
SUPPORTING A PAIR OF 1021 MB HIGHS NEAR 26N60W AND 32N57W. 
ANOTHER DEEP LAYERED TROUGH COVERS THE CENTRAL ATLC SUPPORTING 
ANOTHER COLD FRONT ALONG 32N34W 25N41W 22N52W. SCATTERED SHOWERS 
ARE WITHIN 60 NM OF THE AXIS. A WEAK SURFACE TROUGH IS SOUTH OF 
THE WESTERN END OF THE FRONT ALONG 20N50W TO 17N52W. ISOLATED 
SHOWERS ARE WITHIN 100 NM EITHER SIDE OF THE AXIS. WEAK SURFACE 
RIDGING COVERS THE REMAINDER OF THE EASTERN TROPICAL ATLC AROUND 
A 1017 MB HIGH NEAR 24N29W. A WEAK SURFACE TROUGH IS THE 
NORTHEAST OF THE HIGH CENTER EXTENDING FROM THE CANARY ISLANDS 
TO NEAR 29N24W. NO SHOWER ACTIVITY IS ASSOCIATED WITH THE 
TROUGH. 

FOR ADDITIONAL INFORMATION PLEASE VISIT
HTTP://WWW.HURRICANES.GOV/MARINE

$$
WALTON