[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 221028
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 AM EDT SAT SEP 22 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
0945 UTC.

...TROPICAL WAVES...

TROPICAL WAVE IS ALONG 30W S OF 20N MOVING W 15 KT. NARROW LOW
LEVEL INVERTED-V CURVATURE WITH ASSOCIATED CONVECTION EMBEDDED
WITHIN THE ITCZ.

TROPICAL WAVE IS ALONG 41W/42W S OF 16N MOVING W 10-15 KT. MUCH
OF THE WAVE ENERGY IS WITHIN THE ITCZ WITH A VERY BROAD FAINT
INVERTED-V CURVATURE. WAVE IS BENEATH A BROAD UPPER HIGH ALSO
MASKING THE SIGNATURE WITH ANY CONVECTION TO THE W OF THE WAVE
AXIS.

TROPICAL WAVE IS IN THE CENTRAL CARIBBEAN ALONG 74W/75W S OF 18N
MOVING W 15 KT. THE N PORTION OF THE WAVE LIES BENEATH AN
UPPER LOW AND IS ENHANCING ACTIVITY ASSOCIATED WITH THAT UPPER
LOW. THIS SHALLOW WAVE IS ONLY SEEN ON THE MIMIC TPW ANIMATION
WHICH DEPICTS A NARROW MODEST MOISTURE SURGE MOVING PAST THE ABC
ISLANDS WITH NO ASSOCIATED CONVECTION.

...THE ITCZ...
ITCZ AXIS IS CENTERED ALONG 12N14W 6N22W 10M40W 7N59W. A 1011 MB
LOW IS CENTERED NEAR 6N19W...EMBEDDED WITHIN THE ITCZ...MOVING W
NEAR 15 KT. CLUSTERS OF SCATTERED MODERATE/ISOLATED STRONG
CONVECTION ARE FROM 2N-12N BETWEEN 18W-24W AND FROM 8N-14N
BETWEEN 42W-53W.

DISCUSSION...

GULF OF MEXICO...
AN UPPER LOW IS CENTERED ALONG THE ALABAMA COAST AND IS
ASSOCIATED WITH THE REMNANTS OF T.D. TEN THAT WENT INLAND LATE
ON FRI AND IS CENTERED NEAR MOBILE ALABAMA. SCATTERED SHOWERS/
THUNDERSTORMS CONTINUE OVER THE N GULF COAST N OF 28N TO OVER
FLORIDA FROM PENSACOLA TO THE MISSISSIPPI/LOUISIANA BORDER.
BROAD UPPER RIDGE EXTENDS FROM THE CARIBBEAN ACROSS CENTRAL CUBA
INTO THE W ATLC GENERATING DIFFLUENCE AND ADVECTING AN ABUNDANCE
OF TROPICAL MOISTURE SCATTERED SHOWERS/ISOLATED THUNDERSTORMS
FROM 24N-26N BETWEEN 83W-86W AND SCATTERED SHOWERS ACROSS THE
FLORIDA PENINSULA AND THE IMMEDIATE COASTAL WATERS. AN UPPER
TROUGH COVERS THE REMAINDER OF THE GULF ADVECTING DRY
CONTINENTAL AIR ACROSS THE W GULF W OF 90W THUS LIMITING ANY
ACTIVITY ACROSS THAT AREA.

CARIBBEAN SEA...
BROAD UPPER RIDGE COVERS THE W CARIBBEAN W OF 75W EXTENDING FROM
CENTRAL AMERICA ACROSS CENTRAL CUBA INTO THE W ATLC WITH A
SURFACE TROUGH ANALYZED BENEATH THIS UPPER RIDGE FROM NE YUCATAN
NEAR 22N87W ALONG 17N87W OVER HONDURAS/NICARAGUA TO NEAR 13N85W.
THIS UPPER RIDGE IS GENERATING DIFFLUENCE AND ADVECTING AN
ABUNDANCE OF TROPICAL MOISTURE TO PRODUCE SCATTERED MODERATE/
STRONG CONVECTION WITHIN 100 NM OF LINE FROM 12N80W ALONG 16N83W
TO 20N85W AND CLUSTERS OF SCATTERED SHOWERS/ISOLATED
THUNDERSTORMS OVER THE REMAINDER OF THE AREA W OF 78W. A SMALL
UPPER LOW IS OVER HISPANIOLA BUT IS ONLY PRODUCING WIDELY
ISOLATED SHOWERS OVER THE ISLAND. UPPER RIDGE FROM THE TROPICAL
ATLC COVERS THE REMAINDER OF THE CARIBBEAN WITH DRY SOMEWHAT
STABLE AIR E OF 68W.

ATLANTIC OCEAN...
BROAD UPPER RIDGE EXTENDS FROM THE CARIBBEAN OVER THE FAR W ATLC
W OF 72W ACROSS THE FLORIDA STRAITS GENERATING DIFFLUENCE AND
ADVECTING AN ABUNDANCE OF TROPICAL MOISTURE TO SCATTERED
SHOWERS/THUNDERSTORMS WITHIN 200 NM ALONG THE E COAST OF THE US
N OF 27N TO THE CAROLINAS. THE MAIN FEATURE IN THE CENTRAL ATLC
IS A LONG DRAWN OUT SURFACE TROUGH WHICH EXTENDS THROUGH 32N41W
ALONG 28N44W 24N53W TO 14N58W. SCATTERED SHOWER/ISOLATED
THUNDERSTORMS ARE WITHIN 200 NM E OF THE SURFACE TROUGH N OF 26N
AND WITHIN 150 NM E OF THE SURFACE TROUGH FROM 17N-26N. THIS
SURFACE TROUGH LIES ON THE BOUNDARY BETWEEN AN UPPER TROUGH TO
THE NW AND A BROAD UPPER RIDGE COVERING THE TROPICAL ATLC
CENTERED NEAR 12N40W. A SECOND UPPER TROUGH IS OVER THE FAR E
ATLC EXTENDING FROM THE CANARY TO OVER THE CAPE VERDE ISLANDS
BUT IS NOT PRODUCING ANY SIGNIFICANT ACTIVITY. A BROAD SURFACE
RIDGE COVERS THE E ATLC ANCHORED BY A 1026 MB HIGH E OF THE
AZORES.

$$
WALLACE




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