[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 271037
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 AM EDT TUN SEP 27 2005

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

...TROPICAL WAVES...

E ATLC TROPICAL WAVE IS ALONG 29W/30W S OF 14N MOVING W 15 KT.
LOW/MID LEVEL TURNING IS ALONG THE WAVE AXIS NEAR 9N. SCATTERED
SHOWERS/ISOLATED THUNDERSTORMS ARE FROM 6N-9N BETWEEN 28W-32W.

CENTRAL ATLC TROPICAL WAVE IS ALONG 44W/45W S OF 21N WITH A 1010
MB LOW ALONG THE WAVE NEAR 14N MOVING W 15 KT. BROAD HIGH
AMPLITUDE WAVE WITH A LOW/MID LEVEL TURNING ALONG THE AXIS NEAR
14N. WAVE IS BENEATH S UPPER FLOW AROUND THE BASE OF AN UPPER
HIGH LOCATED TO THE E OF THE WAVE. SCATTERED MODERATE/ISOLATED
STRONG CONVECTION IS WITHIN 60/75 NM OF LINE 15N39W-17N42W.
SCATTERED SHOWERS/ISOLATED THUNDERSTORMS ARE FROM 17N-23N
BETWEEN 44W-49W.

E CARIBBEAN TROPICAL WAVE IS ALONG 74W/75W S OF 20N MOVING W
5-10 KT. THE 1009 MB LOW NEAR 14N74W HAS DISSIPATED. WAVE IS
BENEATH E TO SE UPPER FLOW AT THE BASE OF AN UPPER RIDGE TO THE
E. SCATTERED STRONG CONVECTION IS WITHIN 60 NM OF 75.5W FROM
13N-16N AND SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS
WITHIN 45 NM OF 77W FROM 12N-17N.

W CARIBBEAN TROPICAL WAVE IS ALONG 90W S OF 20N MOVING W 15 KT.
WAVE IS BENEATH NE UPPER FLOW FROM THE RIDGE ANCHORED IN THE
GULF OF MEXICO. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS
INLAND OVER BELIZE AND ALONG THE IMMEDIATE COAST IN THE GULF OF
HONDURAS.

...ITCZ...

ITCZ IS CENTERED ALONG 14N15W 8N31W 14N42W THEN ALONG 12N46W
9N50W 8N56W 9N61W. SCATTERED MODERATE/STRONG CONVECTION IS FROM
7N-12N BETWEEN 38W-42W. SCATTERED MODERATE/ISOLATED STRONG
CONVECTION IS WITHIN 90/120 NM OF AXIS E OF 19W TO INLAND OVER
AFRICA...WITHIN 90 NM OF THE AXIS FROM 33W-38W...AND WITHIN 60
NM OF LINE 9N42W-8N45W.

...DISCUSSION...

THE GULF OF MEXICO...
A BROAD UPPER HIGH IS ANCHORED OVER NW MEXICO COVERING THE GULF
W OF 88W ADVECTING DRY CONTINENTAL AIR AND MODERATE/STRONG
SUBSIDENCE OVER THE W GULF. A CUT-OFF UPPER LOW IS LOCATED JUST
OVER S FLORIDA NEAR 26N81W WITH AN TROUGH EXTENDING N/S S OF 30N
INTO THE NW CARIBBEAN. THE BAY OF CAMPECHE AND S MEXICO REMAINS
MOISTURE LADENED WITH SCATTERED MODERATE/ISOLATED STRONG MAINLY
INLAND OVER S MEXICO WITH SCATTERED SHOWERS/ISOLATED
THUNDERSTORMS IN THE BAY OF CAMPECHE S OF 21N. AT THE
SURFACE...A 1015 MB HIGH IN THE NW GULF NEAR 27N94W. BROAD DEEP
LAYERED TROUGH JUST DIPS INTO THE REGION OVER GEORGIA INTO THE W
ATLC EXTENDING A ATTENDANT COLD FRONT JUST INLAND OVER THE N
GULF COAST. A PRE-FRONTAL TROUGH EXTENDS FROM 33N83W SW THROUGH
A 1011 MB LOW NEAR 30N87W TO 29N91W. THIS IS GENERATING
SCATTERED SHOWERS/ISOLATED THUNDERSTORMS IN THE NE GULF WITHIN
75 NM OF LINE FROM 26N89W TO THE FLORIDA PANHANDLE COAST NEAR
PANAMA CITY.

CARIBBEAN...
THE AREA IS SPLIT BETWEEN THE UPPER TROUGH EXTENDING ACROSS CUBA
NEAR 22N82W OVER THE NW CARIBBEAN TO N OF THE GULF OF HONDURAS
NEAR 17N85W AND AN UPPER RIDGE ANCHORED OVER HISPANIOLA COVERING
THE CARIBBEAN W OF 80W. TROPICAL MOISTURE IS ABUNDANT OVER MOST
OF THE CARIBBEAN GENERATING CLUSTERS OF SCATTERED SHOWERS/
ISOLATED THUNDERSTORMS OVER THE AREA E OF 65W WITH THE GREATEST
INTENSITY ENHANCED BY THE TROPICAL WAVE ALONG 74W/75W.

ATLANTIC...
AN UPPER TROUGH EXTENDING FROM A CUT-OFF LOW OVER S FLORIDA NEAR
26N81W N TO 30N79W. THE UPPER LEVELS ARE RELATIVELY DRY WITH
ISOLATED SHOWERS ORIGINATING OVER HISPANIOLA TO THE TURKS AND
CAICOS BETWEEN 69W-74W. DEEP LAYERED TROUGH IS IN THE W/CENTRAL
ATLC WITH THE UPPER TROUGH AXIS EXTENDING FROM AN UPPER LOW NEAR
32N57W TO 20N61W. ATTENDANT COLD FRONT ENTERS THE REGION NEAR
32N51W EXTENDING SW TO 24N55W THEN CONTINUES AS A SURFACE TROUGH
W TO 21N65W. SCATTERED SHOWERS/ISOLATED THUNDERSTORMS ARE WITHIN
75 NM OF LINE FROM 22N55W TO 32N51W. DIFFLUENCE AT THE BASE OF
THE DEEP LAYERED TROUGH IS GENERATING CLUSTERS OF SCATTERED
MODERATE/ISOLATED STRONG CONVECTION ARE FROM 18N-22N BETWEEN
57W-65W. AN UPPER HIGH IS SW OF THE DEEP LAYERED TROUGH CENTERED
OVER HISPANIOLA NEAR 19N71W AND COVERS A MAJOR PORTION OF THE
CARIBBEAN. TO THE E IS AN UPPER TROUGH THAT EXTENDS FROM AN
UPPER LOW E OF THE CANARY ISLANDS NEAR 29N26W THROUGH 31N40W
ALONG 26N52W INTO THE DEEP TROPICS TO NEAR 12N53W. THIS IS
DRYING OUT THE AREA W OF THE TROPICAL WAVE AND THE W TROPICAL
ITCZ. AN UPPER HIGH IS E OF THE SAME TROPICAL WAVE NEAR 22N37W
WITH A SHARP RIDGE EXTENDING N TO 28N40W. AN UPPER LOW IS MOVING
SW OF THE CAPE VERDE ISLANDS NEAR 11N31W DISRUPTING THE RIDGE
JUST TO THE W. AN UPPER TROUGH CONTINUES DIGGING SW ALONG THE
COAST OF WESTERN SAHARA AND MAURITANIA TO NEAR 19N17W. DRY
AFRICAN LOW LEVEL AIR IS OVER THE E ATLC S OF 23N E OF 20W. AT
THE SURFACE...THE SUBTROPICAL RIDGE REMAINS DIVIDED BETWEEN THE
W AND E ATLC. A 1018 MB HIGH IS SW BERMUDA NEAR 30N69W. THE E
ATLC RIDGE EXTENDS THROUGH 32N32W TO 20N35W.

$$
WALLACE






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