[Tropical] Tropical Weather Discussion

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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




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