[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 091801
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
105 PM EST THU NOV 09 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1745 UTC.

...TROPICAL WAVES...
A BROAD ATLANTIC OCEAN TROPICAL WAVE IS ALONG 45W S OF 15N
MOVING W NEAR 15 KT. THE WAVE IS S OF AN ELONGATED UPPER TROUGH
WHICH IS SHEARING THE HIGH CLOUDS ALONG THE NORTHERN PORTION OF
THE WAVE TO THE NE. HOWEVER...CYCLONIC TURNING IS STILL EVIDENT
IN THE LOWER TO MID CLOUD FIELD UNDERNEATH THESE HIGHER CLOUDS.
A FAIRLY SIGNIFICANT AMOUNT OF SHOWERS/TSTMS SURROUNDS THIS WAVE
WITH NUMEROUS MODERATE/ISOLATED STRONG CONVECTION IS FROM 3N-12N
BETWEEN 40W-50W.

THE TROPICAL WAVE THAT WAS PREVIOUSLY ALONG 56W/57W S OF 14N HAS
BEEN REMOVED...AS THERE HAVE BEEN NO IDENTIFIABLE TROPICAL WAVE
CHARACTERISTICS IN SOME TIME...WITH ITS RECENT PLACEMENT BASED
SOLELY ON CONTINUITY. THE ITCZ HAS ALSO BEEN ADJUSTED FURTHER S
TO THE COAST OF FRENCH GUIANA WITH NE FLOW OBSERVED OFF MUCH OF
NE SOUTH AMERICA.

...THE ITCZ...
ITCZ AXIS IS CENTERED ALONG 10N14W 7N30W 8N43W 8N48W TO THE
FRENCH GUIANA COAST NEAR 5N53W. SCATTERED MODERATE CONVECTION IS
FROM 3N-10N BETWEEN 31W-40W...AND OVER COASTAL NE SOUTH AMERICA
AND THE ADJACENT ATLC WATERS FROM 1N-7N BETWEEN 50W-53W.

...DISCUSSION...
GULF OF MEXICO...
MOSTLY FAIR/DRY WEATHER DOMINATES THE GULF THIS AFTERNOON...WITH
VERTICALLY STACKED HIGH PRESSURE RIDGING AND EXTENSIVE
DRY/STABLE AIR DOMINATING. THE ONLY MOISTURE SEEN IN THE GULF IS
OVER THE FAR W/SW PORTION...WHERE DEBRIS MOISTURE FROM RECENTLY
UPGRADED T.S. ROSA IN THE EPAC SPREADING E/NE WITH UPPER W/SW
FLOW. RETURN SFC FLOW ALSO IN THE W GULF...W OF THE WEAK 1013 MB
SFC HIGH OVER THE NORTH CENTRAL GULF NEAR 27N88W. THE HIGH WILL
CONTINUE SLIDING ENE TOWARDS THE APALACHEE BAY THROUGH
TOMORROW...WITH THE NEXT COLD FRONT ENTERING THE NW PORTION BY
SATURDAY MORNING. SEE MIAOFFNT4 FOR DETAILS.

CARIBBEAN SEA...
A LINGERING COLD FRONT BOUNDARY EXTENDS THROUGH THE NW CARIBBEAN
FROM ERN CUBA TO THE GULF OF HONDURAS. NO DEEP CONVECTION IS
NOTED NEAR THIS BOUNDARY...AND INSTEAD IS MARKED BY A LINE OF
LOWER CLOUDS WITH CONFLUENT LOW LEVEL FLOW. THE ASSOCIATED UPPER
TROUGH JUST OFF THE EASTERN SEABOARD CLIPS THE NRN CARIBBEAN
WATERS NEAR CUBA AND HISPANIOLA. A PAIR OF MID TO UPPER RIDGES
DOMINATES MUCH OF THE REMAINDER OF THE CARIBBEAN. THE FIRST IS
EXTENDING E FROM THE EPAC...THROUGH CENTRAL AMERICA OUT TO 75W
WITH THE AXIS ALONG 15N. THE OTHER MID TO UPPER HIGH IS LOCATED
JUST S OF THE VIRGIN ISLANDS. ASSOCIATED DRY/STABLE AIR IS
SUPPRESSING CONVECTION OVER MUCH OF THE CARIBBEAN N OF 13N. A
WEAK 1009 MB SURFACE LOW IS ANALYZED IN THE SW CARIBBEAN N OF
PANAMA NEAR 11N78W. A COUPLE SMALL CLUSTERS OF SCATTERED
MODERATE CONVECTION NOTED TO THE E/NE OF THIS LOW FROM 10N-13N
BETWEEN 76W-78W. 10-20 KT TRADES DOMINATE MUCH OF THE CARIBBEAN
E OF 80W...AND WILL TAKE OVER MUCH OF THE CARIBBEAN INTO THE
WEEKEND AS THE FRONT IN THE NW PORTION DISSIPATES.

ATLANTIC OCEAN...
AN AMPLIFIED TROUGH/RIDGE/TROUGH/RIDGE PATTERN DOMINATES THE
ATLC BASIN. THE FIRST IN THIS PATTERN IS THE PRONOUNCED UPPER
LOW/TROUGH OFF THE MID ATLC EAST COAST THAT EXTENDS S THROUGH
THE SW NORTH ATLC. THE ASSOCIATED COLD FRONT THAT HAS USHERED
VERY DRY/PLEASANT FALL WEATHER TO THE AREA IS NOW ALONG 31N68W
TO THE SE BAHAMAS NEAR 23N74W. SCATTERED MODERATE CONVECTION IN
THE UNSTABLE ENVIRONMENT AHEAD OF THE FRONT IS FROM 22N-29N
BETWEEN 64W-70W. THIS ACTIVITY ALSO SUPPORTED BY UPPER DIFFLUENT
AIR BETWEEN THE TROUGHING OFF THE EAST COAST AND THE RIDGING
EXTENDING NE FROM THE LEEWARD ISLANDS. THE PREFRONTAL GALE IN
THIS AREA HAS BEEN ALLOWED TO EXPIRE WITH THE STRONGER GRADIENT
NOW N OF THE AREA. AN UPPER LOW IS NEAR 31N38W THAT HAS AN
ASSOCIATED COLD FRONT ALONG 32N33W 23N40W 22N56W. SCATTERED
MODERATE CONVECTION IS ALONG THE NE PORTION OF THIS BOUNDARY
FROM 27N-30N BETWEEN 30W-34W. MINIMAL DEEP CONVECTION NOTED
ELSEWHERE ALONG THE FRONT. N OF THIS OLD FRONT LIES A 1029 MB
SFC HIGH SE OF NEWFOUNDLAND NEAR 43N48W. AHEAD OF THE FRONT IS A
SFC TROUGH ALONG 32N28W 17N39W. ASSOCIATED MODERATE CONVECTION
FROM 26N-32N BETWEEN 26W-30W. THE REMAINDER OF THE E ATLC
DOMINATED BY STACKED RIDGING OFF THE COAST OF AFRICA THROUGH SW
EUROPE.

$$
WILLIS


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