000 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