[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 211131
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
705 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1115 UTC.

...ITCZ/MONSOON TROUGH...

A SMALL PORTION OF THE MONSOON TROUGH EXTENDS FROM THE AFRICAN
COAST OF SIERRA LEONE NEAR 8N13W TO 3N22W. THE INTER-TROPICAL
CONVERGENCE ZONE AXIS EXTENDS WSW FROM 3N22W ALONG 1N35W TO THE
COAST OF BRAZIL NEAR 1S47W. SCATTERED WEAK TO ISOLATED MODERATE
CONVECTION IS WITHIN 100 NM ON EITHER SIDE OF THE ITCZ AXIS
BETWEEN 22W-43W.

...DISCUSSION...

GULF OF MEXICO...
UPPER LEVEL RIDGING CONTINUES TO BUILD ACROSS THE GULF THIS
MORNING 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 AIRMASS ALOFT IS NOTICED ACROSS THE
CARIBBEAN WATERS THIS MORNING...LIMITING ANY SIGNIFICANT DEEP
CONVECTION ACROSS THE DISCUSSION AREA. GENTLE TO MODERATE
EASTERLY TRADES ARE OBSERVED BASIN-WIDE...WITH THE STRONGEST
WINDS GUSTING TO 25 KT NEAR THE COASTAL WATERS OF NRN COLOMBIA.
THIS FLOW PATTERN IS FORECAST TO PERSIST THROUGH THE WEEKEND
WITH NO MAJOR CHANGES EXPECTED TO MODIFY THE CURRENT WEATHER
PATTERN.

ATLANTIC OCEAN...
THE WRN PORTION OF THE DISCUSSION AREA W OF 57W IS UNDER THE
INFLUENCE OF A SURFACE RIDGE ANCHORED BY A 1026 MB HIGH CENTERED
NEAR 31N67W 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 MORNING. AN UPPER LEVEL TROUGH IS TO THE NE OF
THIS LOW LEVEL HIGH PRESSURE CENTER...SUPPORTING A WEAKENING
COLD FRONT ANALYZED FROM 32N54W TO 25N65W. LOW-LEVEL MOISTURE IN
THE VICINITY OF THE FRONT REMAINS LIMITED...WITH A FEW ISOLATED
SHOWERS AND TSTMS OCCURRING AHEAD OF THE FRONT N OF 28N 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 STATIONARY FRONT EXTENDS NORTH FROM THE LOW
CENTER TO OUT OF THE DISCUSSION AREA. A COLD FRONT EXTENDS FROM
THE LOW CENTER ALONG 23N41W TO 19N42W BECOMING STATIONARY TO
15N47W. 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 42N15W.

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

$$

GARCIA




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