000
AXNT20 KNHC 241201
TWDAT 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL  
805 AM EDT SUN OCT 24 2010

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...METEOROLOGICAL ANALYSIS...WEATHER 
OBSERVATIONS...AND RADAR.

BASED ON 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
1015 UTC.

...SPECIAL FEATURE...

TROPICAL STORM RICHARD IS NEAR 16.8N 86.4W AT 24/1200 UTC OR 
ABOUT 30 MI...45 KM N OF ROATAN AND ABOUT 130 MI...205 KM ESE OF 
BELIZE CITY MOVING WNW AT 9 KT. ESTIMATED MINIMUM CENTRAL 
PRESSURE IS 990 MB. MAXIMUM SUSTAINED WIND SPEED IS 60 KT WITH 
GUSTS TO 75 KT. SEE LATEST NHC INTERMEDIATE PUBLIC ADVISORY 
UNDER AWIPS/WMO HEADERS MIATCPAT4/WTNT34 KNHC AND THE FULL 
FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT4/WTNT24 KNHC 
FOR MORE DETAILS. SCATTERED MODERATE/STRONG CONVECTION COVERS 
THE AREA S OF 18N TO INLAND OVER HONDURAS BETWEEN 81W-88W. 
RICHARDS IS EXPECTED TO B ALONG THE COAST OF BELIZE LATE 
TONIGHT/EARLY MON.

...TROPICAL WAVE...

TROPICAL WAVE EXTENDS FROM 24N30W THROUGH A 1009 MB LOW NEAR 
20N32W TO 16N34W MOVING NW 15-20 KT. INVERTED CYCLONIC CURVATURE 
IS WELL DEFINED ON SATELLITE IMAGERY. WAVE IS LOCATED BETWEEN AN 
UPPER RIDGE AND AN UPPER LOW TO THE W PROVIDING UPPER LEVEL 
SHEAR AND DIFFLUENCE ALOFT TO ENHANCE NUMEROUS STRONG WITHIN A 
60 NM RADIUS OF 21N31W WITH SCATTERED MODERATE/STRONG CONVECTION 
COVERING THE REMAINDER OF THE AREA 18N-24N BETWEEN 28W-32W. 

...THE ITCZ...

ITCZ AXIS IS CENTERED ALONG 8N13W 5N22W 10N34W 12N42W THEN 
RESUMES NEAR 11N48W 9N57W 10N64W. A SURFACE TROUGH IS ANALYZED N 
OF THE ITCZ FROM INLAND OVER W AFRICA NEAR 13N15W TO 10N23W. A 
SECOND SURFACE TROUGH IS EMBEDDED WITHIN THE ITCZ EXTENDING FROM 
15N43W TO 8N48W WITH SCATTERED MODERATE/ISOLATED STRONG 
CONVECTION WITHIN 180 NM E OF THE TROUGH N OF 10N. CLUSTERS OF 
SCATTERED MODERATE/ISOLATED STRONG CONVECTION ARE FROM 1N-7N 
BETWEEN 4W-20W AND FROM 4N-8N BETWEEN 20W-30W. 
 
...DISCUSSION...

GULF OF MEXICO...
AN UPPER TROUGH IS MOVING OVER THE NW GULF FROM MOBILE ALABAMA 
TO TAMPICO MEXICO WITH THE ANY ASSOCIATED FRONT WELL INLAND. A 
BROAD UPPER RIDGE COVERS THE REMAINDER OF THE GULF EXTENDING 
FROM THE YUCATAN PENINSULA TO ACROSS NE FLORIDA AND ALONG THE 
COAST OF THE CAROLINAS. A SURFACE RIDGE DOMINATES MOST OF THE 
GULF WATERS ANCHORED BY A 1027 MB HIGH BETWEEN BERMUDA AND THE 
NORTH CAROLINA COAST GIVING THE GULF RETURN FLOW AROUND THE 
SURFACE RIDGE. WATER VAPOR IMAGERY INDICATES STRONG SUBSIDENCE 
AND DRY AIR IMPACTING THE ENTIRE GULF AND SUPPORTING MOSTLY 
CLEAR SKIES ACROSS THE GULF TONIGHT. THE EXCEPTION IS IN THE 
N/CENTRAL GULF WHERE SCATTERED SHOWERS AND A POSSIBLE ISOLATED 
THUNDERSTORM ARE WITHIN 45 NM OF LINE FROM 26N87W TO 28N92W AND 
POSSIBLE ISOLATED SHOWERS OVER THE SE GULF WITHIN 30 NM OF LINE 
FROM 25N87W TO THE FLORIDA STRAITS NEAR 24N81W. 

CARIBBEAN SEA...
THE PRIMARY CONCERN THIS MORNING IS TROPICAL STORM RICHARD OVER 
THE NW CARIBBEAN...SEE SPECIAL FEATURES ABOVE. BROAD UPPER RIDGE 
IS ANCHORED OVER THE YUCATAN PENINSULA AND COVERS THE W 
CARIBBEAN W OF 73W PROVIDING DIFFLUENCE ALOFT AND COUPLED WITH 
AN ABUNDANCE OF TROPICAL MOISTURE ARE GENERATING CLUSTERS OF 
SCATTERED SHOWERS/ISOLATED THUNDERSTORMS S OF 19N TO INLAND OVER 
COLOMBIA BETWEEN 74W-84W. WATER VAPOR IMAGERY INDICATES STRONG 
SUBSIDENCE AND DRY AIR IMPACTING THE E CARIBBEAN E OF 70W AND 
SUPPORTING MOSTLY CLEAR SKIES E OF 73W WITH SOME POSSIBLE 
ISOLATED LOW LEVEL SHOWERS MOVING ACROSS THE AREA INCLUDING THE 
LESSER ANTILLES. 

ATLANTIC OCEAN...
A SHORTWAVE UPPER TROUGH IS MOVING ACROSS THE W ATLC EXTENDING 
FROM 32N71W ACROSS THE BAHAMA ISLANDS TO OVER CUBA NEAR 21N78W. 
A BROAD UPPER RIDGE COVERS THE REMAINDER OF THE W ATLC INTO THE 
CENTRAL AND W TROPICAL ATLC ANCHORED IN THE W TROPICAL ATLC NEAR 
19N62W PROVIDING DIFFLUENCE ALOFT TO GENERATE AN AREA OF 
SCATTERED SHOWERS/ISOLATED THUNDERSTORMS WITHIN 120/150 NM OF 
LINE FROM THE BAHAMAS NEAR 22N73W TO 27N68W. A SURFACE RIDGE 
COVERS THE W ATLC W OF 60W ANCHORED BY A 1027 MB HIGH BETWEEN 
BERMUDA AND THE NORTH CAROLINA COAST LEAVING THE W ATLC W OF 75W 
UNDER MOSTLY CLEAR SKIES THIS MORNING. AN UPPER TROUGH IS IN THE 
CENTRAL ATLC N OF 30N SUPPORTING A COLD FRONT THAT ENTERS THE 
REGION NEAR 32N50W 28N59W TO 28N71W AND A PRE-FRONTAL SURFACE 
TROUGH FROM 31N50W TO 23N72W. SCATTERED SHOWERS AND POSSIBLE 
ISOLATED THUNDERSTORMS ARE WITHIN 120 NM E OF THE FRONT N OF 29N 
WITH ISOLATED SHOWERS BETWEEN THE FRONT AND THE SURFACE TROUGH. 
AN UPPER LOW IS CENTERED NEAR 20N44W SUPPORTING A WEAK 1012 MB 
SURFACE LOW THAT IS W OF THE UPPER LOW NEAR 19N50W. THE UPPER 
LOW IS ENHANCING SCATTERED SHOWERS AND POSSIBLE ISOLATED 
THUNDERSTORMS FROM 17N-26N BETWEEN 33W-44W. AN UPPER RIDGE 
EXTENDS E/W ANCHORED INLAND OVER AFRICA TO 37W ALONG 15N. A 
SURFACE RIDGE DOMINATES THE E ATLC N OF 26N E OF 40W ANCHORED BY 
A 1026 MB HIGH E OF THE AZORES. 

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

$$
PAW