000
AXNT20 KNHC 210530
TWDAT 

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
105 AM EST SAT JAN 21 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
0515 UTC.

...ITCZ/MONSOON TROUGH...

A SMALL PORTION OF THE MONSOON TROUGH EXTENDS FROM THE AFRICAN 
COAST OF SIERRA LEONE NEAR 9N13W TO 5N20W. THE INTER-TROPICAL 
CONVERGENCE ZONE AXIS EXTENDS WSW FROM 5N20W ALONG 1N32W TO THE 
COAST OF BRAZIL NEAR 1S46W. SCATTERED WEAK TO ISOLATED MODERATE 
CONVECTION IS WITHIN 100 NM ON EITHER SIDE OF THE ITCZ AXIS 
BETWEEN 22W-42W.

...DISCUSSION...

GULF OF MEXICO...
UPPER LEVEL RIDGING CONTINUES TO BUILD ACROSS THE GULF THIS 
EVENING AS SHOWN BY WATER VAPOR IMAGERY...THE UPPER RIDGING AXIS 
CURRENTLY EXTENDS NW TO SE ACROSS MEXICO. THIS UPPER LEVEL 
FEATURE IS SUPPORTIVE OF MOSTLY FAIR WEATHER CONDITIONS ACROSS 
THE DISCUSSION AREA. SURFACE OBSERVATIONS INDICATE SOUTHERLY 
RETURN FLOW 10-20 KT ACROSS THE AREA. THIS LOW LEVEL FLOW 
PRECEDES A WEAK FRONTAL BOUNDARY EXPECTED TO ENTER THE NW GULF 
WATERS BRIEFLY SATURDAY MORNING THEN LIFT NORTHWARD BY LATE 
SATURDAY. ANOTHER AREA OF SURFACE LOW PRESSURE IS FORECAST TO 
DEVELOP OVER THE CENTRAL PLAINS AND INTRODUCE A STRONGER COLD 
FRONT INTO THE NW GULF LATE SUNDAY INTO EARLY MORNING WHICH WILL 
PROVIDE NORTHERLY WINDS TO PORTIONS OF THE WESTERN GULF ON 
MONDAY.

CARIBBEAN SEA...
A VERY DRY AND STABLE ATMOSPHERE ALOFT IS NOTICED ACROSS THE 
CARIBBEAN WATERS THIS EVENING...LIMITING ANY SIGNIFICANT AREAS 
OF DEEP CONVECTION ACROSS THE AREA. GENTLE TO MODERATE EASTERLY 
TRADES ARE OBSERVED WITH THE STRONGEST WINDS GUSTING TO 25 KT 
NEAR THE COASTAL WATERS OF NRN COLOMBIA. THIS FLOW IS FORECAST 
TO PERSIST THROUGH THE UPCOMING WEEKEND WITH NO MAJOR CHANGES 
EXPECTED TO MODIFY THE CURRENT WEATHER PATTERN.

ATLANTIC OCEAN...
THE WRN PORTION OF THE DISCUSSION AREA W OF 60W IS UNDER THE 
INFLUENCE OF A SURFACE RIDGE ANCHORED BY A 1025 MB HIGH CENTERED 
NEAR 32N70W WITH AXIS EXTENDING SW ACROSS THE FLORIDA PENINSULA 
INTO THE GULF OF MEXICO. THIS FEATURE IS BRINGING MOSTLY CLEAR 
SKIES AND FAIR WEATHER ACROSS THE BAHAMAS AND THE FLORIDA 
PENINSULA THIS EVENING. AN UPPER LEVEL TROUGH IS TO THE NE OF 
THIS LOW LEVEL HIGH PRESSURE CENTER...SUPPORTING A WEAKENING 
COLD FRONT ANALYZED FROM 32N55W TO 25N67W. LOW-LEVEL MOISTURE IN 
THE VICINITY OF THE FRONT REMAINS LIMITED...WITH A FEW ISOLATED 
SHOWERS AND ISOLATED TSTMS OCCURRING AHEAD OF THE FRONT N OF 30N 
WHERE LOW-LEVEL MOISTURE CONVERGENCE AND UPPER LEVEL DIFFLUENCE 
ARE MAXIMIZED. THIS FRONT IS FORECAST TO CONTINUE TO MOVE OFF TO 
THE NE. A SLOW MOVING 1015 MB LOW PRESSURE SYSTEM IS IN THE 
CENTRAL ATLC CENTERED NEAR 28N44W. THIS LOW IS EXPECTED TO DRIFT 
NORTHWARD AND BECOME ABSORBED INTO THE FRONTAL BOUNDARY BY EARLY 
SUNDAY. CURRENTLY A WARM FRONT EXTENDS NORTH FROM THE LOW CENTER 
TO OUT OF THE DISCUSSION AREA. A STATIONARY FRONT EXTENDS FROM 
THE LOW CENTER ALONG 22N41W TO 15N45W. SCATTERED SHOWERS AND 
POSSIBLE ISOLATED TSTMS ARE OCCURRING WITHIN 130 NM E OF THE 
STATIONARY FRONT...AND WITHIN 250 MN ON THE NORTHEAST SEMICIRCLE 
FROM THE LOW CENTER. THE REMAINDER OF THE EASTERN ATLC IS UNDER 
THE INFLUENCE OF A SURFACE RIDGE ANCHORED BY A 1038 MB HIGH 
CENTERED WEST OF THE IBERIAN PENINSULA NEAR 41N17W.

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

$$

GARCIA