[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 230557
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 AM EDT SAT 23 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
0445 UTC.

...TROPICAL WAVES...
TROPICAL WAVE IN THE TROPICAL ATLC IS ALONG 49W S OF 17N MOVING
W AT 10-15 KT. WAVE IS INTERACTING WITH UPPER LEVEL TROUGH AND
DIVERGENCE ALOFT WHICH IS GREATLY ENHANCING THE AREA CONVECTION.
SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS FROM 10N-15N
BETWEEN 45W-50W.

TROPICAL WAVE IS OVER CENTRAL AMERICA ALONG 87W S OF 17N MOVING
W 10-15 KT. SOUTHERLY FLOW FROM AN UPPER LEVEL HIGH OVER THE
GULF OF MEXICO...STRONG SUBSIDENCE...AND VERY DRY AIR HAS FORCED
ANY SHOWER ACTIVITY S INTO THE E PACIFIC REGION.

...ITCZ...
ITCZ AXIS IS CENTERED ALONG 14N10W 8N24W 8N37W 15N53W 12N70W.
SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS MOVING OFF THE
COAST OF SIERRA LEONE WITHIN 60 NM ALONG THE COAST. CLUSTERS OF
SIMILAR CONVECTION ARE WITHIN 60 NM OF THE AXIS FROM 22W-37W.

...DISCUSSION...
GULF OF MEXICO...
MID/UPPER LEVEL HIGH REMAINS OVER CENTRAL MEXICO NEAR 21N99W
WITH A BROAD RIDGE AXIS EXTENDING NNE ACROSS THE GULF TO OVER
THE MISSISSIPPI VALLEY. ANTICYCLONIC FLOW COVERS ALL OF THE
GULF...MEXICO...SE UNITED STATES...AND YUCATAN PENINSULA. WITH
THIS FLOW STRONG SUBSIDENCE AND DRY AIR ARE LIMITING THE CLOUDS
TO SOME ISOLATED LOW LEVEL CLOUDS. THIS DRY AIR SHOULD ONLY LAST
THROUGH THE NIGHT AS A DEEP LAYERED TROUGH AND ASSOCIATED COLD
FRONT IS MOVING ACROSS NW TEXAS. THIS IS WILL BRING SHOWERS AND
THUNDERSTORMS TO THE NW GULF OVER THE WEEKEND.

W ATLANTIC AND W CARIBBEAN...
DEEP LAYERED TROUGH EXTENDS S THROUGH THE W ATLC INTO THE W
CARIBBEAN WITH THE AXIS TROUGH 32N71W ACROSS THE CENTRAL BAHAMAS
NEAR 23N75W TO OVER CENTRAL AMERICA NEAR NICARAGUA/HONDURAS
BORDER. CYCLONIC FLOW IS WITHIN 300/400 NM OF THE AXIS IN THE
ATLC THEN NARROWS TO WITHIN 180 NM OVER THE CARIBBEAN.
ASSOCIATED COLD FRONT ENTERS THE REGION E OF BERMUDA NEAR 32N63W
SW ALONG 25N70W ACROSS THE CENTRAL BAHAMAS OVER THE N COAST OF
CUBA NEAR 23N80W THEN RETURNS NW TO THE COAST OF MISSISSIPPI
NEAR 30N88W. STRONG SUBSIDENCE/DRY AIR IS W OF THE FRONT
COVERING THE ATLC W OF 70W AND THE CARIBBEAN W OF A LINE FROM
CUBA NEAR 20N75W OVER CENTRAL AMERICA NEAR 13N84W. DUE TO THE
DRY AIR ONLY ISOLATED LOW SHOWERS ARE WITHIN 45 NM OF THE FRONT.

CENTRAL ATLANTIC AND E CARIBBEAN...
MID/UPPER LEVEL HIGH IS 220 NM ENE OF GUADELOUPE NEAR 18N59W
WITH A RIDGE AXIS EXTENDING NE TO 24N50W THEN BROADENS N TO
BEYOND 32N50W AND SW TO THE COAST OF W VENEZUELA NEAR 11N68W.
ANTICYCLONIC FLOW IS WITHIN 300/400 NM OF THE AXIS S OF 24N THEN
BROADENS COVING THE CENTRAL ATLANTIC FROM 35W-63W. AT THE
SURFACE...A 1006 MB LOW IS CENTERED OVER HISPANIOLA NEAR 18N68W
WITH A SURFACE TROUGH EXTENDING NE 25N63W AND SW ALONG 15N76W TO
12N79W. THE SOUTHERLY FLOW OVER THE CARIBBEAN BETWEEN 69W-78W IS
ADVECTING PLENTY OF TROPICAL MOISTURE NORTHWARD WITH UPPER LEVEL
MOISTURE SPREADING ACROSS THE CENTRAL ATLC. SCATTERED MODERATE/
STRONG CONVECTION IS OFF THE COAST OF VENEZUELA WITHIN A 90/120
NM RADIUS OF 13.5N68.5W...E OF LEEWARD ISLANDS FROM 15N-20N
BETWEEN 57W-62W...AND WITHIN 75 NM OF LINE FROM 20N49W 24N49W TO
25N53W. CLUSTERS OF SIMILAR CONVECTION ARE FROM 17N-25N BETWEEN
53W-57W. SCATTERED SHOWERS/ISOLATED THUNDERSTORMS DOT THE AREA N
OF 20N FROM 45W-60W.

E ATLANTIC...
MID/UPPER LEVEL TROUGH IS OVER THE NE ATLC WITH THE AXIS
EXTENDING SW THROUGH 32N12W ACROSS THE CANARY ISLANDS TO A
DEVELOPING UPPER LOW NEAR 25N18W TO 19N27W. AN INDUCED UPPER
LEVEL HIGH IS LOCATED NW OF THE DEVELOPING LOW NEAR 28N27W.
STRONG SUBSIDENCE/DRY AIR IS WITHIN 150/175 NM OF LINE FROM
BEYOND 32N13W 25N22W 26N27W TO 34N25W. THIS IS BRINGING FAIR
SKIES TO THE CANARY ISLANDS TONIGHT. AT THE SURFACE...A 1020 MB
HIGH IS LOCATED NEAR 28N39W WITH A WEAK RIDGE EXTENDING SSE TO
15N71W.

TROPICAL ATLANTIC...
DEVELOPING MID/UPPER LOW IS OFF THE COAST OF SW AFRICA NEAR
6N15W WITH CYCLONIC FLOW S OF 10N FROM 10W-18W. AN EAST/WEST
RIDGE AXIS EXTENDS FROM 7N20W TO A WEAK MID/UPPER LEVEL HIGH
LOCATED NEAR 8N35W WITH ANTICYCLONIC FLOW S OF 12N. OVER THE W
TROPICAL ATLC A WEAK TROUGH AXIS IS ALONG 47W FROM 3N-12N. THIS
UPPER TROUGH IS INTERACTING WITH THE TROPICAL WAVE IN THE AREA.

$$
WALLACE


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