[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 232358
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT SAT OCT 23 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY
THROUGH 2315 UTC.

...SPECIAL FEATURE...

TROPICAL STORM RICHARD IS NEAR 16.2N 84.4W AT 24/0000 UTC OR
ABOUT 140 NM E OF LA CEIBA HONDURAS. RICHARD IS MOVING WESTWARD
AT 7 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 1000 MB. MAXIMUM
SUSTAINED WIND SPEED IS 55 KT WITH GUSTS TO 65 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. SOME
STRENGTHENING IS FORECAST OVER THE NEXT 24 HOURS AS RICHARD
SKIRTS THE HONDURAN COASTLINE TOWARDS BELIZE. NUMEROUS STRONG
CONVECTION IS CURRENTLY NEAR THE CENTER OF RICHARD FROM 15N-17N
BETWEEN 83W-85W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION
EXTENDS FROM 15N-17N BETWEEN 82W-88W. SIMILAR ACTIVITY IS ALSO
FARTHER E DISCONNECTED FROM THE MAIN CONVECTION FROM 11N-21N
BETWEEN 77W-82W.

...TROPICAL WAVE...

TROPICAL WAVE EXTENDS NW OF THE CAPE VERDE ISLANDS ALONG 21N27W
TO 17N31W MOVING NW 10-15 KT. THE LAST VISIBLE SATELLITE IMAGES
OF THE DAY SHOWED BROAD LOW-LEVEL CYCLONIC FLOW ABOUT THE WAVE
AXIS AND CONCENTRATED NEAR A 1011 MB LOW ANALYZED ON THE WAVE
AXIS NEAR 19N30W. TOTAL PRECIPITABLE WATER IMAGERY ALSO
INDICATES A LARGE AREA OF DEEP LAYER MOISTURE ACROSS THE ERN
TROPICAL ATLC WITH MAXIMUM VALUES NEAR THE WAVE. SCATTERED
MODERATE/STRONG CONVECTION IS N OF THE LOW CENTER FROM 20N-22N
BETWEEN 28W-30W. SIMILAR ACTIVITY IS FARTHER SE NEAR THE CAPE
VERDE ISLANDS FROM 16N-19N BETWEEN 24W-27W. THE WAVE IS
CURRENTLY BEING SHEARED BY SWLY FLOW ALOFT BETWEEN AN UPPER
LEVEL TROUGH OVER THE CENTRAL ATLC AND AN UPPER LEVEL RIDGE
CENTERED OVER W AFRICA. WITH THE STRONG SHEAR FORECAST TO
PERSIST...LITTLE DEVELOPMENT OF THE SYSTEM IS EXPECTED OVER THE
NEXT COUPLE OF DAYS.

...THE ITCZ...

ITCZ AXIS IS CENTERED ALONG 6N8W 5N15W 7N21W DISCONNECTED BY THE
TROPICAL WAVE NW OF THE CAPE VERDE ISLANDS RESUMING ALONG 10N29W
7N35W 10N42W 8N50W 10N57W. A SURFACE TROUGH IS ALSO ANALYZED
WITHIN THE ITCZ ALONG 14N44W TO 8N46W. A LARGE BURST OF STRONG
CONVECTION IS MAKING ITS WAY OFF THE COAST OF W AFRICA FROM
8N-12N BETWEEN 13W-18W POSSIBLY ASSOCIATED WITH THE NEXT
TROPICAL WAVE TO MOVE OFF THE COAST. SCATTERED MODERATE/ISOLATED
STRONG CONVECTION IS FROM 6N-10N BETWEEN 20W-24W ASSOCIATED WITH
A WIND SURGE OUT AHEAD OF THE LARGE CONVECTIVE BURST. NO
SIGNIFICANT DEEP CONVECTION IS ELSEWHERE ALONG THE ITCZ.

...DISCUSSION...

THE GULF OF MEXICO...
A BROAD MID-UPPER LEVEL RIDGE IS ACROSS THE GULF OF MEXICO
EXTENDING FROM THE BAY OF CAMPECHE TO THE N ACROSS THE ERN
CONUS. THE UPPER RIDGE SUPPORTS SURFACE RIDGING ACROSS THE BASIN
ANCHORED BY A 1026 MB HIGH OVER ERN N CAROLINA. ANTI-CYCLONIC
SURFACE FLOW OF `5-20 KT IS AROUND THE RIDGE. WATER VAPOR
IMAGERY INDICATES A DRY AIR MASS IS IMPACTING THE AREA
SUPPORTING MOSTLY FAIR WEATHER THROUGHOUT THE GULF. A FEW
ISOLATED SHOWERS ARE NOTED N OF THE YUCATAN PENINSULA MOST
LIKELY ASSOCIATED WITH SMALL AMOUNTS OF MOISTURE ADVECTED NW
FROM TROPICAL STORM RICHARD. EXPECT CONDITIONS TO REMAIN FAIR
ACROSS MUCH OF THE BASIN WITH AN INCREASED CHANCE OF SHOWER
ACTIVITY ACROSS THE SE GULF DUE TO MOISTURE FROM RICHARD MOVING
NW.

THE CARIBBEAN SEA...
TROPICAL STORM RICHARD IS BRINGING HEAVY SHOWERS/THUNDERSTORMS
TO PORTIONS OF HONDURAS AND NICARAGUA. SEE SPECIAL FEATURES
ABOVE FOR MORE DETAILS. THE CIRCULATION OF RICHARD IS ALSO
DRAWING MOISTURE NWD ACROSS THE CENTRAL CARIBBEAN PRODUCING
SCATTERED SHOWERS/THUNDERSTORMS FROM NRN COLOMBIA TO S OF
HISPANIOLA W OF 71W. RICHARD IS UNDER THE INFLUENCE OF A BROAD
UPPER RIDGE THAT IS CENTERED OVER THE YUCATAN PENINSULA. THE ERN
CARIBBEAN IS EXPERIENCING MOSTLY FAIR CONDITIONS UNDER A DRY AIR
MASS MOVING INTO THE AREA AROUND AN UPPER LEVEL RIDGE CENTERED
OVER THE NRN LEEWARD ISLANDS. HOWEVER...A FEW ISOLATED SHOWERS
ARE MAKING THEIR WAY ACROSS THE LESSER ANTILLES AND THE NE
CARIBBEAN ISLANDS. EXPECT MOISTURE TO REMAIN ACROSS MUCH OF THE
WRN HALF OF THE BASIN AS RICHARD MOVES SLOWLY W.

THE ATLANTIC OCEAN...
SURFACE RIDGING CENTERED OVER ERN N CAROLINA IS PRODUCING FAIR
WEATHER ACROSS THE FAR SW N ATLC. HOWEVER...A DEEP LAYER UPPER
LEVEL TROUGH IN THE NW ATLC IS SUPPORTING AN AREA OF CONFLUENCE
AND MOISTURE FROM THE BAHAMAS TO THE NE. THE UPPER TROUGH
SUPPORTS A COLD FRONT ALONG 32N57W 29N73W...AND A PRE-FRONTAL
TROUGH ALONG 32N50W TO 26N64W BECOMING A SHEAR LINE ACROSS THE
CENTRAL BAHAMAS TO NRN CUBA ALONG 24N73W 23N81W. SCATTERED
SHOWERS/ISOLATED THUNDERSTORMS ARE BETWEEN THE FRONT AND THE
TROUGH/SHEARLINE. AN UPPER LEVEL RIDGE CENTERED OVER THE NRN
LEEWARD ISLANDS IS KEEPING CONDITIONS FAIR TO THE SE OF THIS
SYSTEM. FARTHER E...AN UPPER LEVEL LOW CENTERED NEAR 21N41W IS
SUPPORTING A WEAK 1011 MB SURFACE LOW NEAR 20N47W. THE UPPER LOW
IS ALSO ENHANCING A SURFACE TROUGH ALONG THE ITCZ. UPPER LEVEL
DIFFLUENCE BETWEEN THIS UPPER TROUGH AND AN UPPER LEVEL RIDGE
CENTERED OVER W AFRICA IS ENHANCING SCATTERED SHOWERS/POSSIBLE
THUNDERSTORMS FROM 19N-26N BETWEEN 36W-45W. A TROPICAL WAVE IS
IN THE FAR ERN ATLC SUPPORTING SHOWERS/THUNDERSTORMS ACROSS THE
CAPE VERDE ISLANDS. SEE TROPICAL WAVE SECTION FOR MORE DETAILS.
TO THE N...SURFACE RIDGING DOMINATES ANCHORED BY A 1028 MB HIGH
CENTERED OVER THE AZORES ISLANDS.

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

$$
WALTON





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