000
AXNT20 KNHC 152356
TWDAT 

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
705 PM EST TUE JAN 15 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
2345 UTC.

...ITCZ/MONSOON TROUGH...

THE MONSOON TROUGH EXTENDS FROM THE CENTRAL COAST OF LIBERIA 
NEAR 5N9W SOUTHWESTWARD TO 2N11W. THE ITCZ CONTINUES WESTWARD TO 
1N16W 3N26W 1N39W TO NEAR CARUTAPERA BRAZIL. WIDELY SCATTERED 
MODERATE CONVECTION IS FROM 0N-5N BETWEEN 6W-22W. SCATTERED 
SHOWERS ARE FROM 2N-6N BETWEEN 32W-42W.  

...DISCUSSION...

GULF OF MEXICO...
AS OF 2100 UTC...A FRONTAL BOUNDARY REMAINS STATIONARY ALONG THE 
NORTH CENTRAL AND WESTERN GULF ASSISTED BY RETURN FLOW FROM A 
1024 MB SURFACE HIGH IN THE WEST ATLC. THE STATIONARY FRONT 
EXTENDS FROM MOBILE ALABAMA TO THE EAST COAST OF LOUISIANA NEAR 
29N90W AND THEN INTO THE WESTERN GULF ALONG 27N93W 25N94W 23N95W 
20N96W. LIGHT FOG AND SCATTERED SHOWERS ARE WEST OF THE FRONTAL 
BOUNDARY AS WELL AS WITHIN 100 NM EAST OF IT. THE SHOWER 
ACTIVITY IS BEING SUPPORTED BY UPPER LEVEL MOISTURE SITUATED 
OVER THE NW GULF. RETURN FLOW OF MAINLY 10-15 KT SPREADS EAST OF 
THE STATIONARY FRONT. STRONGER NORTHERLY AND NORTHWESTERLY WINDS 
OF 20 KT ARE WEST OF THE FRONT. THE REMAINDER OF THE GULF ENJOYS 
FAIR WEATHER CONDITIONS BEING SUPPORTED BY BOTH SURFACE AND 
UPPER LEVELS RIDGING AS WELL AS DRY AIR SUBSIDENCE. OVER THE 
COURSE OF 24 HOURS...THE HIGH PRESSURE OVER THE WEST ATLC WILL 
DISPLACE EASTWARD AND COLD AIR WILL ADVECT INTO THE WESTERN GULF 
ALLOWING THE FRONTAL TRANSITION FROM STATIONARY TO COLD. GALE 
FORCE WINDS ARE ALSO EXPECTED TO DEVELOP WEST OF THE FRONTAL 
SYSTEM. FOLLOWING THE 24 HOUR PERIOD...STORM FORCE WINDS ARE 
POSSIBLE. 

CARIBBEAN SEA...
WEST OF PUERTO RICO AND NORTH OF 14N...THE CARIBBEAN REGION IS 
DOMINATED BY TRADE WINDS OF 15-20 KT WITH LIGHTER WINDS BEING IN 
THE WESTERN CARIBBEAN WEST OF JAMAICA. NORTHEASTERLY FLOW OF 
10-15 KT IS TO THE SOUTH OF PUERTO RICO AND ALONG THE LESSER 
ANTILLES. THE SAME TYPE OF FLOW BUT SLIGHTLY STRONGER IS FOUND 
ALONG THE COAST OF COLOMBIA. NO CONVECTIVE ACTIVITY OR 
SIGNIFICANT SHOWERS ARE OBSERVED OVER THE ENTIRE REGION. FAIR 
WEATHER CONDITIONS ARE BEING SUPPORTED BY STRONG DRY AIR 
SUBSIDENCE FROM ALOFT. OVER THE COURSE OF 24 HOURS...TRADE WINDS 
WILL CONTINUE TO DOMINATE THE REGION WITH A POSSIBLE INCREASE IN 
WIND SPEED TO 25 KT OVER THE CENTRAL CARIBBEAN. 

ATLANTIC OCEAN...
OVER THE WESTERN ATLC...BOTH SURFACE AND UPPER LEVEL RIDGING 
ALONG WITH DRY AIR SUBSIDENCE ARE PROVIDING FAIR WEATHER 
CONDITIONS TO THE AREA. IN THE CENTRAL ATLC...A COLD FRONT 
ASSOCIATED TO A SURFACE LOW NEAR 31N41W EXTENDS FROM 30N36W 
SOUTHWESTWARD TO 25N37W 21N40W 17N44W. SIGNIFICANT SHOWER 
ACTIVITY AND THUNDERSTORMS ARE WITHIN 200 NM EITHER SIDE OF THE 
COLD FRONT NORTH OF 20N. GALE FORCE WINDS ARE IN THE AREA...N OF 
26N E OF 41W.  THIS FRONTAL SYSTEM AND CONVECTIVE ACTIVITY IS 
BEING SUPPORTED BY AN UPPER LEVEL LOW CENTERED NEAR THE POSITION 
OF THE SURFACE LOW. IN THE EAST ATLC...SURFACE RIDGING FROM A 
HIGH POSITIONED SW OF PORTUGAL DOMINATES THE REGION. WIDESPREAD 
SCATTERED SHOWERS ARE FROM 9N TO 22N BETWEEN 21W AND 37W.

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

$$
RAMOS