000
AXNT20 KNHC 041758
TWDAT 

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
105 PM EST FRI JAN 04 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
1715 UTC.

...ITCZ/MONSOON TROUGH...

THE INTERTROPICAL CONVERGENCE ZONE AXIS EXTENDS FROM THE WEST 
AFRICAN COAST NEAR 05N10W TO THE EQUATOR NEAR 42W THEN TO THE 
BRAZIL COAST NEAR 02S45W. SCATTERED MODERATE CONVECTION IS 
WITHIN 180 NM OF THE AXIS FROM 12W-18W AND WITHIN 180 NM N OF 
THE AXIS FROM 28W-33W.

...DISCUSSION...

GULF OF MEXICO...
A DISTINCT STATIONARY FRONT CONTINUES ACROSS THE GULF OF MEXICO 
TODAY EXTENDING FROM THE S FLORIDA PENINSULA NEAR 26N82W TO 
21N94W TO 19N92W IN THE BAY OF CAMPECHE.  TROUGHING IN THE 
EXTREME W GULF IS ACTING TO CONTINUE THE COLD AIR ADVECTION 
ALONG THE MEXICAN COAST. WHILE THE FRONT HAS LITTLE UPPER LEVEL 
DYNAMICAL SUPPORT...NUMEROUS MID TO UPPER LEVEL CLOUDINESS IS 
APPARENT N OF THE FRONT WITH WIDELY SCATTERED THUNDERSTORMS 
IN THE BAY OF CAMPECHE AND SCATTERED SHOWERS ELSEWHERE.  THE 
SHOWERS AND THUNDERSTORMS ARE BEING ENHANCED BY THE INCREASED 
MOISTURE SEEN IN THE TOTAL PRECIPITABLE WATER IMAGERY.  NORTH OF 
THE FRONT AND EAST OF THE TROUGH...SURFACE WINDS ARE OUT OF THE 
NORTHEAST AT 20 TO 30 KT.  TO THE WEST OF THE TROUGH...NW WINDS 
ARE 25 TO 30 KT..AS THE EARLIER GALE CONDITIONS HAVE 
DIMINISHED.  DUE TO CONTINUED MODERATE COLD AIR ADVECTION FROM 
THE US GULF COAST STATES...THE FRONTAL BOUNDARY SHOULD REMAIN IN 
PLACE OR EVEN RETROGRADE NORTHWARD AS A WARM FRONT IN THE 
WESTERN HALF OF THE GULF OF MEXICO.

CARIBBEAN SEA...
NO SIGNIFICANT FEATURES OR DEEP CONVECTION ARE OCCURRING TODAY 
OVER THE CARIBBEAN SEA.  A MODERATE PRESSURE GRADIENT IS 
BECOMING ESTABLISHED BETWEEN THE SURFACE RIDGE OVER THE WESTERN 
ATLANTIC AND LOW PRESSURE OVER NW SOUTH AMERICA.  THIS SHOULD 
ENHANCE THE NE TO E TRADEWINDS N OF COLUMBIA TO GALE FORCE 
COMMENCING THIS EVENING AND REMAINING IN PLACE FOR A COUPLE OF 
DAYS. SCATTERED SHOWERS ARE SEEN OVER THE W CARIBBEAN AND THE 
UPSLOPE PORTIONS OF CENTRAL AMERICA NORTHWARD TO BELIZE.

ATLANTIC OCEAN...
THE ATLANTIC IS BEING TRAVERSED BY TWO COLD FRONTAL BOUNDARIES 
TODAY...ONE FROM THE S FLORIDA PENINSULA ENE TOWARD 31N68W AND A 
SECOND FROM 29N49W ENE TOWARD 31N35W.  SCATTERED SHOWERS ARE 
PRESENT WITHIN 240 NM N OF THE WESTERN FRONT AND WITHIN 180 NM 
OF THE EASTERN FRONT. N OF THE FRONTS...WINDS OF 10-20 KT OUT OF 
THE NE ARE FOUND.  E OF 70W...THE SURFACE IS DOMINATED BY A A 
RIDGE OF HIGH PRESSURE.  S OF THE SURFACE RIDGE...NE TO E 
TRADEWINDS OF 10-20 KT ARE OCCURRING.  N OF THE SURFACE 
RIDGE...SW TO W WINDS OF 10-20 KT ARE BEING PRODUCED.  UPPER 
LEVEL RIDGING IS DOMINATING FROM 50W TO 80W...WHILE A SHARP 
TROUGH IS PRESENT FROM NEAR W AFRICA AT 31N16W TO 15N28W TO 
02N35W. THIS TROUGH IS ADVECTING SUBSTANTIAL UPPER LEVEL 
CLOUDINESS WITHIN 300 NM E OF THE TROUGH AXIS. THERE ARE SOME 
ISOLATED SHOWERS EMBEDDED WITHIN THIS UPPER LEVEL CLOUDINESS.

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

$$
LANDSEA