[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 110018
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT MON SEP 10 2007

TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL
AMERICA...THE GULF OF MEXICO...THE CARIBBEAN SEA...NORTHERN
SECTIONS OF SOUTH AMERICA...AND THE 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 DEPRESSION GABRIELLE CONTINUES TO MOVE AWAY FROM THE
UNITED STATES. AS OF 10/2100 UTC THE CENTER OF THE DEPRESSION
WAS NEAR 37.6N 71.0W OR ABOUT 260 NM SOUTH OF NANTUCKET
MASSACHUSETTS.  GABRIELLE IS MOVING EAST-NORTHEAST AT 15 KT.
MAXIMUM SUSTAINED WINDS REMAIN 30 KT WITH GUSTS TO 40 KT.  THE
ESTIMATED MINIMUM CENTRAL PRESSURE IS 1009 MB.  PLEASE REFER TO
THE NHC FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS
MIATCMAT2/WTNT22 KNHC AND/OR THE PUBLIC ADVISORY
MIATCPAT2/WTNT32 KNHC FOR MORE DETAILS.  PRESENTLY AN AREA OF
THUNDERSTORMS IS SOUTHEAST OF THE CENTER HOWEVER NORTHWESTERLY
SHEAR PERSISTS AND THE OVERALL CIRCULATION APPEARS TO BE LESS
DEFINED THAN IT WAS EARLIER TODAY.  THE DEPRESSION IS EXPECTED
TO MERGE WITH A FRONTAL SYSTEM IN ABOUT 36-48 HOURS.  IF THE
DEPRESSION DOES NOT GENERATE MORE ORGANIZED CONVECTION THAN
CURRENTLY OBSERVED...IT MAY NOT SURVIVE AS A TROPICAL CYCLONE
FOR THAT LONG.

...TROPICAL WAVES...

TROPICAL WAVE IS JUST EAST OF THE CAPE VERDE ISLANDS ALONG 23W
S OF 18N MOVING W 10-15 KT.  A LARGE BAND OF LOW CLOUDS WITH
BROAD CYCLONIC TURNING IS NOTED MOSTLY FROM 15N-22N BETWEEN
22W-30W.  SCATTERED MODERATE TO STRONG CONVECTION IS W OF THE
WAVE AXIS ALONG THE ITCZ FROM 9N-12N BETWEEN 25W-32W.

AN ACTIVE TROPICAL WAVE IS ALONG 42W S OF 17N MOVING W 10-15 KT.
A 1010 MB LOW IS EMBEDDED ON THE WAVE AXIS NEAR 9N42W.  THIS
SYSTEM IS GRADUALLY BECOMING BETTER ORGANIZED AND HAS THE
POTENTIAL TO DEVELOP INTO A TROPICAL DEPRESSION DURING THE NEXT
COUPLE OF DAYS.  WIDELY SCATTERED MODERATE CONVECTION IS FROM
9N-13N BETWEEN 37W-43W.

TROPICAL WAVE IS OVER THE LESSER ANTILLES ALONG 62W S OF 20N
MOVING W AT 10-15 KT.  SCATTERED MODERATE TO ISOLATED STRONG
CONVECTION IS OVER THE NORTHERN APEX OF THE WAVE FROM 17N-20N
BETWEEN 61W-63W.  WIDELY SCATTERED MODERATE CONVECTION IS OVER
THE SOUTHERN PORTIONS OF THE WAVE AXIS FROM 8N-12N BETWEEN
58W-64W.  SIGNIFICANT DEVELOPMENT OF THIS WAVE IS NOT EXPECTED
OVER THE NEXT SEVERAL DAYS.

...THE ITCZ...
ITCZ AXIS IS CENTERED ALONG 8N11W 10N23W 10N40W 8N45W 10N60W.
BESIDES FOR THE CONVECTION ASSOCIATED WITH THE TROPICAL WAVES...
WIDELY SCATTERED MODERATE CONVECTION IS ALONG THE COAST OF W
AFRICA 9N-12N BETWEEN 13W-16W.  SCATTERED MODERATE CONVECTION IS
FROM 6N-10N BETWEEN 46W-49W.

DISCUSSION...

THE GULF OF MEXICO...
A 1010 MB LOW IS OVER THE WESTERN GULF OF MEXICO NEAR 25N94W.  A
SURFACE TROUGH EXTENDS FROM NW GULF NEAR 30N93W TO THE LOW
CENTER TO THE BAY OF CAMPECHE NEAR 19N93W.  WIDELY SCATTERED
MODERATE CONVECTION IS NEAR THE LOW CENTER FROM 23N-26N BETWEEN
91W-96W.  FURTHER E ...ISOLATED MODERATE CONVECTION IS OVER
CENTRAL FLORIDA AND THE SE GULF FROM 23N-27N BETWEEN 80W-90W.
IN THE UPPER LEVELS...A SMALL UPPER LEVEL LOW IS CENTERED OFF
THE COAST OF FLORIDA NEAR 28N84W.  A SMALL UPPER LEVEL HIGH IS
CENTERED OVER THE BAY OF CAMPECHE NEAR 19N91W.  A SMALL UPPER
LEVEL LOW IS CENTERED OVER INLAND MEXICO NEAR 21N100W.
CONSIDERABLE UPPER LEVEL MOISTURE COVERS THE GULF OF MEXICO S OF
28N.  EXPECT...MORE CONVECTION OVER THE NORTHERN AND WESTERN
GULF DURING THE NEXT 24 HOURS.

THE CARIBBEAN SEA...
A TROPICAL WAVE IS OVER THE EASTERN CARIBBEAN SEA.  SEE ABOVE.
LIGHT TO MODERATE TRADES ARE OVER THE REMAINDER OF THE SEA.
SCATTERED MODERATE TO ISOLATED STRONG CONVECTION IS OVER THE
WESTERN CARIBBEAN SEA...NICARAGUA...AND HONDURAS FROM 11N-15N
BETWEEN 79W-86W.  A 1008 MB LOW IS OVER N COLOMBIA NEAR 8N75W.
SCATTERED MODERATE TO STRONG CONVECTION IS NE OF THE LOW FROM
8N-12N BETWEEN 72W-76W.  FURTHER N...SCATTERED MODERATE
CONVECTION IS OVER HAITI FROM 18N-20N BETWEEN 72W-74W.  SIMILAR
CONVECTION IS OVER THE S COAST OF CUBA BETWEEN 76W-82W.  IN THE
UPPER LEVELS...RIDGING IS OVER THE W CARIBBEAN SEA W OF 80W.  AN
UPPER LEVEL LOW IS CENTERED OVER HISPANIOLA NEAR 18N70W.
CYCLONIC FLOW IS FROM 10N-25N BETWEEN 60W-80W.  EXPECT
CONVECTION WITH THE TROPICAL WAVE DURING THE NEXT 24 HOURS.
ALSO EXPECT CONVECTION OVER THE WESTERN CARIBBEAN AND CENTRAL
AMERICA W OF 80W DURING THE NEXT 24 HOURS.

THE ATLANTIC OCEAN...
A 1022 MB HIGH IS OVER THE W ATLANTIC NEAR 32N69W.  TWO WEAK SFC
TROUGHS STRETCH THROUGH THE CENTRAL ATLANTIC.  THE MAIN TROUGH
ENTERS THE AREA NEAR 32N36W AND EXTENDS MAINLY SW ALONG 25N50W
24N65W. THE TROUGH IS PRETTY ACTIVE WEST OF 55W...WHERE
SATELLITE IMAGERY SHOWS A 60 NM WIDE BAND OF SHOWERS AND TSTMS.
A SECONDARY TROUGH WITH MUCH LESS SHOWER ACTIVITY IS CLIPPING
THE AREA ALONG 30N BETWEEN 42W-58W.  A 1022 MB HIGH IS OVER THE
E ATLANTIC NEAR 32N27W.  IN THE UPPER LEVELS... A TROUGH IS OVER
THE W ATLANTIC W OF 60W.  A LARGE UPPER LEVEL HIGH IS OVER THE E
ATLANTIC NEAR 21N25W.  A RIDGE AXIS EXTENDS W TO 15N50W.

OF NOTE...TODAY MARKS THE CLIMATOLOGICAL PEAK OF THE HURRICANE
SEASON. SO FAR...THE ONLY HURRICANES THAT HAVE FORMED...DEAN
AND FELIX...BECAME CATEGORY FIVE HURRICANES ON THE
SAFFIR-SIMPSON SCALE. IN ADDITION BOTH DEAN AND FELIX MADE
LANDFALL AS CATEGORY FIVE HURRICANES WITH SUSTAINED WINDS OF
NEAR 145 KT AND 140 KT RESPECTIVELY. THIS REPRESENTS THE FIRST
TIME THAT TWO CATEGORY FIVE HURRICANES HAVE MADE LANDFALL IN THE
ONE ATLANTIC SEASON.

$$
GR





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