[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 201054
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 AM EDT WED 20 OCT 2004

TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL
AMERICA... GULF OF MEXICO...CARIBBEAN SEA...NORTHEASTERN
SECTIONS OF SOUTH AMERICA...AND ATLC 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1015 UTC.

...TROPICAL WAVES...
TROPICAL WAVE IN THE CENTRAL TROPICAL ATLC IS ALONG 44W MOVING W
5-10 KT. THIS WAVE IS UNDER AN AREA OF CONFLUENCE BETWEEN AN
UPPER LOW TO THE W AND AN UPPER HIGH TO THE E. NO ASSOCIATED LOW
LEVEL CONVECTION.

TROPICAL WAVE IN THE CARIBBEAN IS ALONG 74W S OF 20N MOVING W
5-10 KT. WAVE HAS MOVED BENEATH AN UPPER ANTICYCLONIC FLOW
WHICH IS LIMITING CONVECTION TO THE E OF THE WAVE AXIS.
SCATTERED SHOWERS/THUNDERSTORMS ALONG THE COAST OF NE COLOMBIA/
NW VENEZUELA S OF 14N FROM 68W-74W.

...ITCZ...
ITCZ AXIS IS ALONG 16N10W 9N30W 13N62W. CLUSTERS OF SCATTERED
MODERATE/ISOLATED STRONG CONVECTION ARE FROM 3N-10N BETWEEN
22W-42W.

...DISCUSSION...
GULF OF MEXICO AND NW CARIBBEAN...
MID/UPPER LEVEL HIGH IS CENTERED INLAND OVER CENTRAL MEXICO WITH
RIDGE AXIS EXTENDING N OVER THE CENTRAL UNTIED STATES AND E
ACROSS THE GULF AND NW CARIBBEAN W OF 80W. A RIDGE AXIS ALSO
EXTENDS FROM 28N80W NE OVER THE NW ATLC BEYOND 32N76W. THE UPPER
HIGH IS BRINGING STRONG SUBSIDENCE/DRY AIR TO THE AREA S OF 27N
W OF 90W AND S OF 22N W OF 80W INCLUDING MEXICO...THE YUCATAN
PENINSULA...HONDURAS...AND MOST OF NICARAGUA. DIVERGENCE BETWEEN
THE UPPER RIDGE OVER THE GULF AND THE UPPER TROUGH OVER THE W
ATLC IS PRODUCING SCATTERED MODERATE/ISOLATED STRONG CONVECTION
N OF 27N E OF 84W TO OVER FLORIDA.

W ATLANTIC AND REMAINDER OF CARIBBEAN...
AT THE SURFACE...HIGH PRESSURE COVERS THE W ATLC WITH A SURFACE
RIDGE AXIS EXTENDING FROM A 1023 MB HIGH NE OF BERMUDA THROUGH
32N62W TO FLORIDA NEAR 25N80W. DEEP LAYERED TROUGH EXTENDS OVER
THE W ATLC INTO THE CARIBBEAN N OF 15N W OF A LINE FROM 32N47W
21N60W TO 15N74W AND BOUNDED TO THE W AT 80W. A SHORTWAVE AXIS
EXTENDS 32N68W SW TO CUBA NEAR 21N76W AND A SECOND SHORTWAVE
AXIS EXTENDS FROM 32N52W TO AN UPPER LOW NEAR 25N60W. AN AREA OF
UPPER DIVERGENCE BETWEEN THE UPPER RIDGE OVER THE GULF AND THE
UPPER TROUGH OVER THE W ATLC IS PRODUCING SCATTERED MODERATE/
ISOLATED STRONG CONVECTION N OF 27N W OF 76W TO JUST INLAND OVER
THE THE SE UNITED STATES COAST. A SURFACE TROUGH EXTENDS THROUGH
32N47W SW TO 24N58W THEN S TO THE LEEWARD ISLANDS NEAR 18N62W.
MODERATE SUBSIDENCE/DRY AIR ARE WITHIN 150/180 NM NE OF THE E
SHORTWAVE TROUGH AXIS. MID/UPPER LEVEL RIDGE COVERS THE
REMAINDER OF THE CARIBBEAN WITH THE AXIS EXTENDING FROM OVER
SOUTH AMERICA NEAR 9N62W N OVER THE LESSER ANTILLES TO 20N60W.
THIS ANTICYCLONIC FLOW IS PROVIDING TROPICAL MOISTURE IN
CONJUNCTION WITH THE TROPICAL TO PRODUCE SCATTERED SHOWERS/
THUNDERSTORMS ALONG THE COAST OF NE COLOMBIA/NW VENEZUELA S OF
14N FROM 68W-74W. CONVERGENCE ALOFT BETWEEN THE UPPER HIGH OVER
THE GULF AND TROUGH ARE PRODUCING SCATTERED SHOWERS/
THUNDERSTORMS WITHIN 90 NM OF LINE 17N80W-9N82W.

CENTRAL/EASTERN ATLANTIC...
BROAD ANTICYCLONIC FLOW COVERS THE CENTRAL ATLC BOUNDED BY THE
TROUGH TO THE W AND A TROUGH TO THE E PRODUCING ALMOST ZONAL
WESTERLY FLOW FROM 30W-50W. WEAK DEEP LAYERED TROUGH COVERS THE
NE ATLC N OF 23N E OF 30W. ASSOCIATED SURFACE LOW/FRONTAL SYSTEM
IS N OF THE REGION.

TROPICAL ATLANTIC...
NEAR STATIONARY...CUTOFF MID/UPPER LOW IN THE W TROPICAL ATLC IS
CENTERED NEAR 12N55W COVERING THE AREA FROM 7N-18N BETWEEN
50W-58W. REMAINDER OF THE TROPICAL ATLC IS DOMINATED BY A
MID/UPPER HIGH CENTERED NEAR 12N33W AND COVERS THE REMAINDER OF
THE TROPICS. AN AREA OF UPPER CONVERGENCE WITH SCATTERED
MODERATE/STRONG CONVECTION IS WITHIN 125 NM OF A LINE FROM
7N28W-13N39W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS
FROM 10N-14N BETWEEN 44W-48W AND FROM 14N-19N BETWEEN 43W-49W.
CLUSTERS OF SCATTERED MODERATE CONVECTION IS WITHIN 90 NM OF
LINE FROM 13N33N-16N42W.

$$
WALLACE



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