[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 140549
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 AM EDT THU SEP 14 2006

TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL
AMERICA...THE GULF OF MEXICO...THE CARIBBEAN SEA...NORTHEASTERN
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...WEATHER OBSERVATIONS...RADAR...
AND METEOROLOGICAL ANALYSIS.

BASED ON 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
0345 UTC.

...SPECIAL FEATURES...
HURRICANE GORDON IS CENTERED NEAR 27.8N 57.1W AT 14/0300 UTC
MOVING NORTH-NORTHEAST AT 11 KT. ESTIMATED MINIMUM CENTRAL
PRESSURE IS 955 MB. MAXIMUM SUSTAINED WIND SPEED IS 105 KT WITH
GUSTS TO 130 KT. SEE THE LATEST NHC FORECAST/ADVISORY UNDER
AWIPS/WMO HEADERS MIATCMAT2/WTNT22 KNHC FOR MORE DETAILS. GORDON
HAS A SMALL VERY DISTINCT EYE WITH UNIFORM CONVECTION
SURROUNDING THE EYE. SCATTERED MODERATE/ISOLATED STRONG
CONVECTION IS WITHIN 90/120 NM FROM THE CENTER IN ALL QUADRANTS.

TROPICAL DEPRESSION EIGHT WAS UPGRADED TO TROPICAL STORM AT
14/0300 UTC. TROPICAL STORM HELENE IS CENTERED NEAR 13.3N 32.7W
AT 14/0300 MOVING WEST-NORTHWEST AT 19 KT. ESTIMATED MINIMUM
CENTRAL PRESSURE IS 1005 MB. MAXIMUM SUSTAINED WIND SPEED IS 35
KT WITH GUSTS TO 45 KT. SEE THE LATEST NHC FORECAST/ADVISORY
UNDER AWIPS/WMO HEADERS MIATCMAT3/WTNT23 KNHC FOR MORE DETAILS.
HELENE CONTINUES TO BECOME MORE ORGANIZED WITH THE DEEPEST
CONVECTION REMOVED FROM THE CENTER. SCATTERED STRONG CONVECTION
IS NW OF THE CENTER WITHIN 45 NM OF LINE 16N31W-15N35W. CLUSTERS
OF SCATTERED MODERATE/STRONG CONVECTION ARE FROM 8N-17N BETWEEN
28W-38W.

...TROPICAL WAVES...

TROPICAL WAVE IS ALONG 45W S OF 13N MOVING W 10-15 KT. LOW
AMPLITUDE WAVE EMBEDDED WITHIN A LAYER OF AFRICAN DUST THUS NO
ASSOCIATED CONNECTION.

TROPICAL WAVE IS ALONG 53W/54W S OF 14N MOVING W 10-15 KT. WAVE
IS MOVING TOWARD AN AREA OF UPPER DIFFLUENCE THAT EXTENDS N FROM
OVER THE LESSER ANTILLES. SMALL CLUSTERS OF SCATTERED MODERATE
CONVECTION ARE FROM 10N-14N BETWEEN 49W-56W.

TROPICAL WAVE IS ALONG 63W S OF 18N MOVING W 15 KT. LOW LEVEL
INVERTED-V SATELLITE SIGNATURE IS OBSERVED OVER THE SE
CARIBBEAN. WAVE IS BENEATH AN AREA OF UPPER DIFFLUENCE THAT
EXTENDS N FROM OVER THE LESSER ANTILLES.

TROPICAL WAVE IS ALONG 73W/74W S OF 18N MOVING W 15 KT. WEAK LOW
LEVEL INVERTED-V SATELLITE SIGNATURE IS OBSERVED OVER THE
S/CENTRAL CARIBBEAN. WAVE IS EMBEDDED WITHIN VERY DRY AIR THUS
NO ASSOCIATED CONVECTION.

...THE ITCZ...
ITCZ AXIS IS CENTERED ALONG 16N16W 14N28W 8N43W 8N50W 11N62W
ACROSS THE N PORTION OF SOUTH AMERICA AND PANAMA NEAR 9N80W INTO
THE E PACIFIC REGION. SCATTERED MODERATE/STRONG CONVECTION IS
MOVING OFF AFRICA WITHIN 90 NM OF LINE 17N21W TO INLAND OVER
AFRICA NEAR 12N14W. SCATTERED MODERATE/ISOLATED STRONG
CONVECTION IS WITHIN 90/120 NM OF THE AXIS FROM 48W-50W WITH
CLUSTERS OF SIMILAR CONVECTION FROM 7N-17N E OF 35W TO THE COAST
OF AFRICA.

...DISCUSSION...

GULF OF MEXICO...
BROAD DEEP LAYERED TROUGH COVERS THE E US AND ALONG THE N GULF
COAST ANCHORED BY AN UPPER LOW MOVING OVER THE GREAT LAKES
REGION. THE ASSOCIATED FRONTAL BOUNDARY EXTENDS INTO THE GULF
THROUGH A 1009 MB LOW OVER THE FLORIDA PANHANDLE NEAR
TALLAHASSEE SW TO 28N89W WHERE IT BECOMES NEAR STATIONARY THE
TEXAS/MEXICO BORDER. SCATTERED SHOWERS/ISOLATED THUNDERSTORMS
ARE OVER THE NE GULF N OF 29N E OF FRONT. UPPER RIDGE EXTENDS
ACROSS THE REMAINDER OF THE GULF ANCHORED BY AN UPPER HIGH OVER
CENTRAL MEXICO ACROSS TAMPICO MEXICO TO TAMPA FLORIDA INTO THE W
ATLC. THIS IS GENERATING SCATTERED SHOWERS/THUNDERSTORMS FROM
25N-27N E OF 85W TO INLAND OVER S FLORIDA. MID LEVEL LOW IS IN
THE SW GULF NEAR 21N94W GENERATING SCATTERED SHOWERS/ISOLATED
THUNDERSTORMS S OF 22N INTO THE BAY OF CAMPECHE W OF 93W TO OVER
MEXICO.

CARIBBEAN SEA...
W CARIBBEAN IS DOMINATED BY NNE UPPER FLOW FROM THE UPPER RIDGE
THAT EXTENDS ACROSS THE GULF OF MEXICO INTO THE W ATLC. THIS IS
PROVIDING DRY AIR ACROSS THE AREA INCLUDING THE TROPICAL WAVE
ALONG 73W/74W. AN UPPER LOW IS IN THE CENTRAL CARIBBEAN NEAR
14N74W WITH THE UPPER TROUGH EXTENDING FROM HISPANIOLA TO JUST
OFF CENTRAL PANAMA. E CARIBBEAN IS DOMINATED BY S UPPER FLOW
FROM AN UPPER RIDGE ANCHORED IN THE TROPICAL ATLC. THIS RIDGE IS
DRAWING ABUNDANT TROPICAL MOISTURE ACROSS THE E CARIBBEAN AND
GENERATING SCATTERED SHOWERS/THUNDERSTORMS OVER THE NE CARIBBEAN
N OF 14N E OF 64W INCLUDING THE VIRGIN/LEEWARD ISLANDS. SIMILAR
ACTIVITY IS ACROSS THE S CARIBBEAN S OF 12N DUE TO THE PROXIMITY
OF THE ITCZ AXIS.

ATLANTIC OCEAN...
UPPER RIDGE AXIS EXTENDS FROM THE GULF OF MEXICO INTO THE W ATLC
ACROSS FLORIDA NEAR DAYTONA BEACH TO NEAR 31N68W. BENEATH THIS
UPPER RIDGE IS A SURFACE TROUGH THAT EXTENDS FROM 31N70W THROUGH
A 1011 MB LOW NEAR 27N73W ACROSS THE BAHAMAS TO NEAR 23N78W.
THIS IS GENERATING SCATTERED SHOWERS/ISOLATED THUNDERSTORMS NE
OF THE LOW FROM 27N-30N BETWEEN 68W-73W. AN UPPER LOW IS IN THE
W ATLC JUST TO THE E OF THE RIDGE NEAR 25N68W WITH THE UPPER
TROUGH EXTENDING S ACROSS HISPANIOLA INTO THE CARIBBEAN
GENERATING SCATTERED SHOWERS FROM 23N-27N BETWEEN 62W-70W. BROAD
UPPER RIDGE COVERS THE W/CENTRAL ATLC ANCHORED IN THE TROPICS
NEAR 20N54W COVERING THE AREA FROM 48W-66W. ABUNDANCE OF
TROPICAL MOISTURE IS BEING DRAWN ACROSS THE E CARIBBEAN AND WITH
SUFFICIENT DIFFLUENCE IS GENERATING AN AREA OF SCATTERED
MODERATE/ISOLATED STRONG CONVECTION FROM 15N-22N BETWEEN
56W-64W. GORDON IS EMBEDDED BENEATH THIS UPPER RIDGE. AN UPPER
LOW IN THE N/CENTRAL ATLC EXTENDS AN UPPER TROUGH S INTO THE
REGION NEAR 32N45W TO 22N45W. HOWEVER...DUE TO THE DRY AIR IN
PLACE NO SHOWER ACTIVITY IS CLEARLY EVIDENT. BROAD UPPER RIDGE
COVERS THE REMAINDER OF THE ATLC E OF 38W ANCHORED NEAR 29N30W
EXTENDING E TO OVER THE CANARY ISLANDS AND NW AFRICA. AT THE
SURFACE...A RIDGE COVERS THE ATLC N OF 20N E OF 50W WITH A 1028
MB HIGH JUST SE OF THE AZORES. THE LAST VISIBLE SATELLITE IMAGES
SHOWS A LARGE AREA OF AFRICA DUST FROM 8N-30N BETWEEN 32W-50W
WITH HELENE JUST TO THE E OF THIS DUST.

$$
WALLACE



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