000
AXNT20 KNHC 121149
TWDAT 

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 AM EDT MON MAR 12 2012

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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
1115 UTC.

...ITCZ/MONSOON TROUGH...

THE MONSOON TROUGH EXTENDS ACROSS W AFRICA INTO THE E TROPICAL 
ATLC NEAR 8N13W TO 5N17W WHERE THE ITCZ AXIS CONTINUES ALONG 
2N24W 1N32W S OF THE EQUATOR NEAR 37W INTO SOUTH AMERICA NEAR 
3S43W. CLUSTERS OF SCATTERED MODERATE/ISOLATED STRONG CONVECTION 
ARE FROM 6N TO JUST S OF THE EQUATOR BETWEEN 4W-26W. CLUSTERS OF 
SCATTERED MODERATE CONVECTION ARE FROM 3N TO S OF THE EQUATOR 
BETWEEN 27W-39W. 

...DISCUSSION...

GULF OF MEXICO...
A STRONG UPPER LOW IS MOVING INTO THE UPPER MISSISSIPPI VALLEY 
WITH THE UPPER TROUGH EXTENDING S TO OVER LOUISIANA SUPPORTING A 
DISSIPATING COLD FRONT THAT IS INLAND OVER ARKANSAS AND 
LOUISIANA. A REMNANT SURFACE TROUGH EXTENDS OVER THE GULF WATERS 
AT 12/0900 UTC FROM 29N94W TO 26N96W WITH SCATTERED SHOWERS AND 
POSSIBLE ISOLATED THUNDERSTORMS WITHIN 150 NM E OF THE TROUGH N 
OF 28N AND ISOLATED SHOWERS W OF THE TROUGH TO INLAND OVER 
TEXAS. A SECOND SURFACE TROUGH IS OVER THE BAY OF CAMPECHE 
EXTENDING FROM 24N94W TO THE COAST OF S MEXICO NEAR 18N93W WITH 
ISOLATED SHOWERS W OF THE SURFACE TROUGH TO INLAND OVER MEXICO S 
OF 24N. A BROAD UPPER RIDGE DOMINATES THE GULF WATERS WITH THE 
MEAN AXIS EXTENDING THROUGH THE YUCATAN CHANNEL TO INLAND OVER 
THE SE GULF STATES NEAR APALACHEE BAY FLORIDA. A SURFACE RIDGE 
EXTENDS FROM THE W ATLC AND A 1033 MB HIGH OFF NORTH CAROLINA TO 
S LOUISIANA. THE SE RETURN OVER THE E GULF IS PRODUCING 
SCATTERED SHOWERS NE OF A LINE FROM THE STRAITS OF FLORIDA NEAR 
23N80W ALONG 27N87W TO THE MISSISSIPPI/LOUISIANA BORDER. THIS IS 
LEAVING THE REMAINDER OF THE GULF UNDER MOSTLY CLEAR SKIES THIS 
MORNING. THE SURFACE TROUGH OVER THE NW GULF WILL SHIFT W OF 
AREA TODAY AS THE SURFACE RIDGE BUILDS W FROM THE W ATLC ACROSS 
GULF OF MEXICO THROUGH FRI.

CARIBBEAN SEA...
WEAK UPPER TROUGH EXTENDS FROM THE W ATLC ACROSS HAITI TO THE E 
TIP OF JAMAICA AMPLIFYING AN UPPER RIDGE THAT EXTENDS FROM THE E 
GULF OF HONDURAS THROUGH THE YUCATAN CHANNEL INTO THE GULF OF 
MEXICO. A BROAD UPPER RIDGE OVER THE TROPICAL ATLC DOMINATES THE 
CARIBBEAN E OF 70W WITH NEAR ZONAL WESTERLY FLOW OVER THE SW 
CARIBBEAN. MODERATE/STRONG SUBSIDENCE AND DRY STABLE AIR ARE W 
OF A LINE FROM THE LEEWARD ISLANDS NEAR 17N62W TO COLOMBIA NEAR 
12N72W AND S OF 20N W OF 77W. REMNANT ISOLATED SHOWERS DOT THE 
AREA WITHIN 75 NM OF LINE FROM SW HAITI NEAR 18N72W ACROSS 
JAMAICA TO HONDURAS NEAR 16N85W. THE UPPER RIDGE OVER THE E 
CARIBBEAN IS DRAWING MOISTURE ALOFT AND IS GENERATING SCATTERED 
SHOWERS SE OF LINE FROM THE LEEWARD ISLANDS NEAR 17N62W TO 
15N70W INCLUDING THE WINDWARD AND ABC ISLANDS. THIS IS LEAVING 
THE REMAINDER OF THE CARIBBEAN UNDER MOSTLY CLEAR SKIES THIS 
MORNING. THE TIGHT PRESSURE GRADIENT IS PRODUCING FRESH TO 
STRONG NE TO E TRADE WINDS ACROSS THE BASIN. LITTLE CHANGE IS 
EXPECTED THROUGH FRI.

ATLANTIC OCEAN...
A SURFACE RIDGE COVERS THE W ATLC W OF 60W ANCHORED BY A 1033 MB 
HIGH OFF NORTH CAROLINA. A BROAD UPPER TROUGH EXTENDS INTO THE W 
ATLC THROUGH 32N55W ALONG 25N64W NARROWING AS IT ENTERS THE 
CARIBBEAN OVER HAITI SUPPORTING A 1008 MB SURFACE LOW NEAR 
32N49W WITH A COLD FRONT EXTENDING S ALONG 29N50W TO 24N55W. 
SCATTERED SHOWERS/ISOLATED THUNDERSTORMS ARE WITHIN 180 NM E OF 
THE FRONT. BROAD UPPER RIDGE COVERS THE TROPICAL ATLC S OF 25N 
BETWEEN 30W-60W WITH A NARROW RIDGE EXTENDING FROM 25N40W TO 
BEYOND 32N35W WITH NEAR ZONAL WESTERLY FLOW ALOFT E OF 30W. A 
SURFACE RIDGE DOMINATES THE E ATLC ANCHORED BY A 1026 MB HIGH 
ABOUT 350 NM SW OF THE AZORES. THE FIRST VISIBLE SATELLITE 
IMAGES SHOW AN AREA OF AFRICAN DUST COVERING THE E TROPICAL ATLC 
FROM 7N-28N E OF 40W. THE COLD FRONT WILL MOVE INTO THE CENTRAL 
ATLC TUE WHERE IT WILL STALL AND WEAKEN THROUGH WED NIGHT AND 
DISSIPATE BY EARLY FRI. SURFACE RIDGE OVER THE W ATLC WILL 
REMAIN THROUGH WED BEFORE SHIFTING E THU AND FRI.

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

$$
PAW