[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 011153
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
705 AM EST FRI FEB 01 2008

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
1115 UTC

...THE ITCZ...
ITCZ AXIS IS CENTERED ALONG 2N1W 2N20W 4N26W 1N46W. SCATTERED
MODERATE CONVECTION NOTED WITHIN 60 NM N AND WITHIN 120 NM S
OF AXIS E OF 23W AND S OF 5N TO COAST OF S AMERICA W OF 40W.

...DISCUSSION...
GULF OF MEXICO...
IN THE UPPER LEVELS A CYCLONE OVER SW INDIANA TRAILS A SHORTWAVE
TROUGH SW ALONG 31N91W 21N95W. A SHORTWAVE UPPER RIDGE...
ORIGINATING FROM A WEAKENING ANTICYCLONE CENTERED OVER THE NW
BAHAMAS...EXTENDS W INTO THE AREA ALONG 24N TO NEAR 83W. A
SURFACE RIDGE IS ALMOST IN PHASE WITH THE UPPER FEATURE AND
EXTENDS SW ALONG 25N80W TO THE YUCATAN PENINSULA BUT THIS RIDGE
IS SHIFT E IN ADVANCE OF A COLD FRONT ALONG 31N86W 19N95W.
CONVECTION CONTINUES TO FLARE ABOUT 90 NM AHEAD OF THE FRONT
WITH LIGHTNING DATA CURRENTLY CLUSTERED OVER THE GULF WATERS N
OF 26N. BROKEN LOW CLOUDS ARE NOTED ELSEWHERE WITHIN 90 NM E OF
THE FRONT. OTHERWISE THE UPPER LEVELS ARE DRY OVER THE GULF OF
MEXICO.

CARIBBEAN SEA...
IN THE UPPER LEVELS AN ANTICYCLONE IS CENTERED OVER THE NW
BAHAMAS WITH ITS ENVELOPE OF ANTICYCLONIC NE TO E FLOW
DOMINATING THE UPPER LEVELS OF THE CARIBBEAN W OF 65W.
ASSOCIATED DRY UPPER AIR CONTINUES TO SUPPRESS DEEP CONVECTIVE
DEVELOPMENT. AN UPPER CYCLONE IS CENTERED NE OF THE AREA NEAR
18N58W AND IS MOVING WSW WITH TIME WITH THE UPPER LEVEL FLOW W
TO NW OVER THE AREA S OF S OF 15N E OF 65W. SURFACE HIGH PRES N
OF THE AREA CONTINUES TO DRIVE NE WINDS...AND LOCALLY BROKEN LOW
CLOUDS WITH EMBEDDED LIGHT SHOWERS SW ACROSS MOST OF THE
CARIBBEAN SEA EXCEPT FOR THE SW PORTION. LOW LEVEL SOUTHERLY
RETURN FLOW CONTINUES OVER THE NW WATERS WITH SHOWERY CLOUDS
DEVELOPING WITHIN 120 NM 20N83W AND MOVING N AS A COLD FRONT
OVER THE CENTRAL GULF OF MEXICO APPROACHES.

ATLC OCEAN...
AN UPPER LEVEL ANTICYCLONE IS CENTERED OVER THE NW BAHAMAS BUT
IS WEAKENING AS A LONGWAVE RIDGE DOMINATING THE CENTRAL N ATLC
BUILDS SW ACROSS THE BAHAMAS TO THE NW CARIBBEAN. AN UPPER
ANTICYCLONE IS NEAR 29N51W WITH ITS ENVELOPE COVERING THE AREA N
OF 24N BETWEEN 43W AND 60W AND ANTICYCLONIC FLOW ALSO DOMINATES
THE ENTIRE DISCUSSION AREA W OF 67W. THIS W ATLC RIDGE WILL
LIKELY BLOCK THE CONTINUED E ADVANCE OF THE SHORTWAVE TROUGH NOW
OVER THE CENTRAL GULF OF MEXICO.

AN UPPER LEVEL TROUGH...OR TUTT...LIES TO THE SE OF THE LONGWAVE
RIDGE. THE TUTT IS FIRST NOTICED IN A SUBTROPICAL UPPER CYCLONE
WEAKENING NEAR 39N16W...WIT THE UPPER TROUGH EXTENDING WSW ALONG
31N29W INTO ANOTHER UPPER CYCLONE AT 21N40W...CONTINUING SW TO
ANOTHER CYCLONE AT 17N57W. CONVECTION IS ENHANCED OVER THE NE
QUADRANT OF THE WESTERNMOST CYCLONE NEAR 17N57W. A LOW LEVEL
TROUGH LIES ALONG 28N64W 18N56W 10N53W. THE UPPER LEVELS ARE SO
DRY THE RESULTANT DEBRIS MOISTURE FROM THIS CONVECTION IS
TRAPPED WITHIN 180 NM EITHER SIDE OF LINE 23N58W 17N50W. ANOTHER
LOW LEVEL TROUGH IS NOTED FROM 25N37W TO 16N36W WITH SCATTERED
SHOWERS ENHANCED N OF 21N WITHIN 240 NM EITHER SIDE OF ITS AXIS.
THE UPPER MOISTURE IS STREAMING NE TO NEAR 27N30W.

AN UPPER ANTICYCLONE IS NEAR THE EQUATOR AT 27W WITH ITS RIDGE
CRESTING OVER THE DISCUSSION AREA ALONG 10N63W 20N35W 26N17W.
AVIATORS TAKE NOTE...TRANSVERSE CIRRIFORM CLOUDS ARE NOTED ALONG
THE N PERIPHERY OF THIS RIDGE INDICATING UPPER LEVEL TURBULENCE.
DENSE DEBRIS MOISTURE IS ALSO NOTED S OF 10N BETWEEN 30W AND
55W. AT THE LOW LEVELS BRISK NE TO E FLOW AND LOCALLY BROKEN
STRATOCUMULUS CLOUDS ARE NOTED E OF 50W.

$$
NELSON





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