[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 210559
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 AM EDT TUE SEP 21 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
0515 UTC.

...SPECIAL FEATURES...

HURRICANE IGOR IS CENTERED NEAR 41.3N 57.5W AT 21/0600 UTC OR
ABOUT 325 NM SSW OF CAPE RACE NEWFOUNDLAND MOVING NE AT 26 KT.
ESTIMATED MINIMUM CENTRAL PRESSURE IS 968 MB. MAXIMUM SUSTAINED
WIND SPEED IS 65 KT WITH GUSTS TO 80 KT. IGOR IS EMBEDDED WITHIN
INCREASING SOUTHWESTERLY SHEAR WITH DEEP CONVECTION DISPLACED
WELL N OF THE CENTER. SCATTERED MODERATE CONVECTION IS FROM
41N-47N BETWEEN 54W-61W. IGOR IS EXPECTED TO BECOME EXTRA-
TROPICAL WITHIN THE NEXT 24 HOURS. SEE LATEST NHC INTERMEDIATE
PUBLIC ADVISORY UNDER AWIPS/WMO HEADERS MIATCPAT1/WTNT31 AND THE
FULL FORECAST ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT1/WTNT21
KNHC FOR MORE DETAILS.

TROPICAL DEPRESSION FOURTEEN IS CENTERED NEAR 17.1N 31.9W AT
21/0300 UTC OR ABOUT 460 NM W OF THE CAPE VERDE ISLANDS MOVING N
AT 5 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 1006 MB. MAXIMUM
SUSTAINED WIND SPEED IS 30 KT WITH GUSTS TO 40 KT. GRADUAL
STRENGTHENING IS FORECAST OVER THE NEXT FEW DAYS AS THE TROPICAL
CYCLONE REMAINS SOUTH OF AN EASTERN ATLC TROUGH IN A MINIMAL
VERTICAL SHEAR ENVIRONMENT. SCATTERED MODERATE TO STRONG
CONVECTION IS FROM 13N-19N BETWEEN 27W-33W. SEE LATEST NHC
FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT4/WTNT24 KNHC
FOR MORE DETAILS.

...TROPICAL WAVES...

TROPICAL WAVE EXTENDS FROM 09N19W TO 19N16W MOVING W AT 10-15
KT. A 1009 MB LOW IS ANALYZED ALONG THE WAVE AXIS NEAR 17N17W.
CIMSS WAVETRAK MODEL GUIDANCE INDICATES A NARROW AREA OF 850 MB
RELATIVE VORTICITY IS ASSOCIATED WITH THE WAVE AXIS LOCATED
ALONG THE W AFRICA COAST FROM 09N-20N. A SURGE OF DEEP LAYER
MOISTURE JUST OFF THE COAST IS ALSO EVIDENT IN TPW IMAGERY.
ISOLATED MODERATE CONVECTION IS FROM 13N-17N BETWEEN 18W-21W.

TROPICAL WAVE EXTENDS FROM 07N60W TO 17N61W MOVING W AT 10-15
KT. ENERGY ASSOCIATED WITH THIS WAVE HAS TRACKED WESTWARD ACROSS
THE TROPICAL ATLC OVER THE PAST SEVERAL DAYS AND CONTINUES TO
EXHIBIT BROAD CYCLONIC LOW-LEVEL FLOW OVER THE EASTERN
CARIBBEAN. TOTAL PRECIPITABLE WATER VALUES REMAIN HIGH FROM
08N-15N BETWEEN 56W-63W. SCATTERED MODERATE AND ISOLATED STRONG
CONVECTION IS FROM 11N-15N BETWEEN 59W-62W AND WEST OF THE WAVE
AXIS FROM 12N-17N BETWEEN 63W-65W.

...ITCZ...

A MONSOONAL TROUGH IS ANALYZED FROM SW OF T.D. FOURTEEN NEAR
16N33W TO 11N45W. THE ITCZ AXIS THEN RESUMES NEAR 12N46W AND
EXTENDS TO 13N60W. SCATTERED MODERATE AND ISOLATED STRONG
CONVECTION IS FROM 06N-09N BETWEEN 24W-28W.

...DISCUSSION...

GULF OF MEXICO...
AN UPPER LEVEL RIDGE EXTENDS ACROSS THE GULF OF MEXICO AND
FLORIDA PENINSULA STEMMING FROM AN UPPER LEVEL ANTICYCLONE
CENTERED OVER NORTHERN MEXICO NEAR 24N105W. THIS ANTICYCLONE IS
PROVIDING THE GULF WITH NW TO N UPPER LEVEL FLOW AND PRIMARILY
STABLE CONDITIONS ALOFT WHILE SUPPORTING BROAD SURFACE RIDGING.
WIDELY SCATTERED SHOWERS ARE OCCURRING IN THE WESTERN GULF N OF
22N W OF 90W DUE TO LOW-LEVEL WARM AIR ADVECTION AND WEAK
SURFACE TROUGHING EXTENDING ALONG THE TEXAS AND MEXICO GULF
COASTS.

CARIBBEAN SEA...
WHILE UPPER LEVEL NORTHERLY FLOW IS OVER THE NW CARIBBEAN AND
PORTIONS OF CENTRAL AMERICA W OF 83W...AN UPPER LEVEL TROUGH
EXTENDS FROM THE W ATLC ACROSS CENTRAL CUBA TO NEAR 13N83W. DRY
AIR ALOFT ASSOCIATED WITH THE TROUGHING IS PROVIDING FAIR
CONDITIONS OVER CUBA TONIGHT...HOWEVER AS THE TROUGH CONTINUES
TO DIP INTO THE WESTERN CARIBBEAN WATERS...ISOLATED SHOWERS ARE
FROM 15N-20N BETWEEN 76W-84W. FARTHER EAST...AHEAD OF THE TROUGH
AXIS...MOIST SW UPPER LEVEL FLOW IS GENERATING AN EXTENSIVE AREA
OF LOW-LEVEL CLOUDINESS AND POSSIBLE ISOLATED SHOWERS FROM
13N-20N BETWEEN 67W-74W...INCLUDING MOST OF HISPANIOLA. THIS
AREA STRETCHES NORTHWARD INTO THE SW NORTH ATLC BETWEEN 65W-72W
WHERE A WEAKNESS IN THE SUBTROPICAL RIDGE IS LOCATED. THE
REMAINDER OF THE EASTERN CARIBBEAN IS INFLUENCED BY THE TROPICAL
WAVE ALONG 61W THAT CONTINUES MOVING WESTWARD AND GENERATING
SCATTERED SHOWERS AND TSTMS OVER THE LESSER ANTILLES AND AN AREA
FROM 12N-17N BETWEEN 63W-65W. ANOTHER AREA OF INTEREST IN THE
CARIBBEAN SEA BASIN IS A SURFACE TROUGH ANALYZED FROM 13N73W TO
THE COAST OF NICARAGUA NEAR 13N83W AND INLAND OVER INTERIOR
PORTIONS OF CENTRAL AMERICA TO CENTRAL GUATEMALA NEAR 16N90W.
THIS MONSOON TROUGH DENOTES THE BOUNDARY BETWEEN SOUTHWESTERLY
FLOW ORIGINATING IN THE E PACIFIC REGION AND EAST-NORTHEASTERLY
FLOW OVER THE WESTERN CARIBBEAN. SCATTERED SHOWERS AND ISOLATED
TSTMS ARE FROM 08N-13N BETWEEN 69W-79W AND OVER CENTRAL AMERICA
WITHIN 90 NM EITHER SIDE OF THE MONSOON TROUGH AXIS.

ATLANTIC OCEAN...
A SHARP UPPER LEVEL TROUGH AXIS EXTENDS ACROSS THE W ATLC FROM
32N71W TO CENTRAL CUBA NEAR 22N80W AND INTO THE WESTERN
CARIBBEAN SEA. THIS TROUGHING IS SUPPORTING THE ADVECTION OF
MID-LEVEL MOISTURE AND POSSIBLE ISOLATED SHOWERS FROM 20N-23N
BETWEEN 65W-75W. THE TROUGHING ALSO COINCIDES WITH AN OVERALL
WEAKNESS IN THE SUBTROPICAL RIDGE BETWEEN 65W-72W...HOWEVER
WEATHER CONDITIONS IN THIS AREA REMAIN FAIRLY BENIGN. ELSEWHERE
ACROSS THE CENTRAL AND EASTERN ATLC...A SURFACE RIDGE DOMINATES
ANCHORED BY A 1017 MB HIGH CENTERED NEAR 27N49W. THE RIDGE AXIS
EXTENDS FROM THE HIGH CENTER E-NE TO 32N30W AND FROM THE HIGH
CENTER SW TO 22N65W. THIS SURFACE HIGH IS SUPPORTED ALOFT BY A
LARGE UPPER LEVEL ANTICYCLONE CENTERED NEAR 30N50W.

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

$$
HUFFMAN




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