000 AXNT20 KNHC 280007 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 805 PM EDT SUN AUG 27 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 2315 UTC. ...SPECIAL FEATURES... ERNESTO IS DOWNGRADED TO A TROPICAL STORM BUT STILL BRINGING TORRENTIAL RAINS TO HAITI AND THE DOMINICAN REPUBLIC. IT IS CENTERED NEAR 18.2N 74.4W AT 28/0000 UTC MOVING NW AT 6 KT. THIS POSITION IS VERY NEAR THE SOUTHWESTERN TIP OF HAITI AND ABOUT 120 NM SSE OF GUANTANAMO CUBA. ESTIMATED MINIMUM CENTRAL PRESSURE HAS RISEN TO ABOUT 1004 MB. THE MAXIMUM SUSTAINED WIND HAVE DECREASED TO NEAR 45 KT WITH HIGHER GUSTS. SEE THE LATEST NHC FORECAST/ADVISORY UNDER HEADERS MIATCMAT5/WTNT25 KNHC FOR MORE DETAILS. APPARENTLY...THE HIGHLY MOUNTAINOUS TERRAIN OF THE SOUTHWESTERN PENINSULA OF HAITI HAS DISRUPTED THE CIRCULATION OF ERNESTO AND THE LOW-LEVEL CENTER HAS BECOME BROAD AND ILL-DEFINED. THIS TROPICAL CYCLONE IS FORECAST TO STRENGTHEN AFTER IT MOVES AWAY FROM SOUTHWESTERN HAITI AND IT COULD REGAIN HURRICANE STATUS BEFORE IT REACHES THE SOUTH COAST OF EASTERN CUBA TOMORROW MORNING. OUTER RAINBANDS CONTINUE TO AFFECT HISPANIOLA. RAINFALL AMOUNTS OF 6 TO 12 INCHES...WITH POSSIBLE ISOLATED AMOUNTS OF UP TO 20 INCHES...ARE EXPECTED OVER HAITI...THE DOMINICAN REPUBLIC...AND PORTIONS OF CUBA. THESE RAINS COULD CAUSE LIFE-THREATENING FLASH FLOODS AND MUD SLIDES. SCATTERED MODERATE TO STRONG CONVECTION IS FROM 17N-19N BETWEEN 73W-75W. CLUSTERS OF SIMILAR CONVECTION ARE ALONG THE CARIBBEAN COAST OF DOMINICAN REPUBLIC. TROPICAL DEPRESSION DEBBY IS CENTERED NEAR 31.5N 48.6W AT 27/2100 UTC MOVING N AT 15 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 1012 MB. THE MAXIMUM SUSTAINED WIND SPEED IS 25 KT WITH GUSTS TO 35 KT. DEBBY IS LOOKING RATHER ELONGATED AND CONTINUES TO GENERATE LIMITED AND INTERMITTENT BURSTS OF CONVECTION TO THE NORTH OF THE CENTER. BECAUSE OF THE LACK OF PERSISTENT ORGANIZED CONVECTION...DEBBY IS NO LONGER A TROPICAL CYCLONE. THE LAST ADVISORY WAS ISSUED AT 27/2100 UTC. ...TROPICAL WAVES... HIGH AMPLITUDE TROPICAL WAVE IS ALONG 33W S OF 23N WITH A 1010 MB LOW ALONG THE WAVE AXIS NEAR 17N MOVING W 15-20 KT. WAVE/LOW REMAINS EMBEDDED WITHIN AN AREA OF DRY AIR AND AFRICAN DUST LIMITING ACTIVITY ALONG THE WAVE. ISOLATED SHOWERS AND THUNDERSTORMS ARE ASSOCIATED WITH THE LOW CENTER. TROPICAL WAVE IS INLAND OVER SOUTH MEXICO INTO THE EPAC ALONG 93/94W S OF 18N MOVING W 15-20 KT. MOST OF THE CONVECTIVE ACTIVITY RELATED TO THIS WAVE IS ON THE PACIFIC SIDE. ...THE ITCZ... ITCZ IS CENTERED ALONG 15N17W 9N30W 7N45W 7N58W. SCATTERED MODERATE CONVECTION IS FROM 7N-11N BETWEEN 22W-28W. CLUSTERS OF MODERATE/ISOLATED STRONG CONVECTION ARE ALONG THE WEST COAST OF AFRICA FROM 7N-14N. ISOLATED SHOWERS AND TSTMS ARE ELSEWHERE. ...DISCUSSION... GULF OF MEXICO... BROAD UPPER RIDGE COVERS THE SE U.S. WITH AN UPPER HIGH OVER CENTRAL GEORGIA. THE RIDGE ALSO DOMINATES THE GULF AND THE W ATLC. THIS SYSTEM IS PRODUCING ELY UPPER LEVEL FLOW OVER THE N GULF. AT THE SURFACE...A 1017 MB HIGH IS CENTERED OVER THE GULF NEAR 27N89W. LIGHT AND VARIABLE WINDS ARE FOUND OVER THE E GULF UNDER THE INFLUENCE OF THIS HIGH. THE REMAINDER OF THE GULF HAS 10-15 KT SLY FLOW. SCATTERED SHOWERS AND TSTMS AREA OVER THE E GULF. A CLUSTER OF MODERATE CONVECTION IS OVER THE YUCATAN PENINSULA...PROBABLY ASSOCIATED WITH AN UPPER LOW MOVING ACROSS THIS AREA. ACCORDING TO THE CURRENTLY OFFICIAL FORECAST TRACK... ERNESTO...AS A HURRICANE IS EXPECTED TO MOVE INTO THE SE GULF ON WED. CARIBBEAN SEA... THE MAIN FEATURE TO FOLLOW THIS EVENING IS TROPICAL STORM ERNESTO THAT IS MOVING TOWARD EASTERN CUBA. A HURRICANE WARNING REMAINS IN EFFECT FROM CAMAGUEY TO GUANTANAMO. FOR MORE DETAILS SEE SPECIAL FEATURES ABOVE. IN ADDITION...CLUSTERS OF SCATTERED MODERATE CONVECTION IS INLAND OVER WESTERN VENEZUELA AND NORTHERN COLOMBIA DUE PRIMARILY TO THE ITCZ. A LARGE UPPER LOW COVERS THE NW CARIBBEAN WEST OF 83W...NORTHERN CENTRAL AMERICA AND THE YUCATAN PENINSULA. THIS LOW IS FORECAST TO MOVE INTO THE BAY OF CAMPECHE TOMORROW. BROAD UPPER HIGH DOMINATES THE EASTERN CARIBBEAN. A DIFFLUENCE PATTERN ALOFT IS OVER ERNESTO. ERNESTO WILL CONTINUE TO BE THE PREDOMINATE WEATHER PRODUCER IN THE CARIBBEAN DURING THE NEXT 24-36 HOURS. ATLANTIC OCEAN... THE UPPER RIDGE THAT COVERS THE SE U.S EXTENDS INTO THE W ATLC W OF 70W. A WEAK UPPER TROUGH IS ALONG 31N65W 22N74W. THE UPPER RIDGE OVER THE E CARIBBEAN EXTENDS NEWD ACROSS PUERTO RICO TO NEAR 31N55W. A LARGER UPPER LOW IS OVER THE CENTRAL ATLANTIC NEAR 25N52W PRODUCING SLY UPPER LEVEL SHEAR OVER T.D. DEBBY WEAKENING THE SYSTEM. UPPER LEVEL RIDGING IS ACROSS THE REMAINDER OF THE ATLC AND W AFRICA. AT THE SURFACE...A TROUGH LIES ALONG 31N55W 28N62W 30N70W. WIDELY SCATTERED CONVECTION IS ALONG AND AHEAD OF THIS TROUGH. ANOTHER SURFACE TROUGH EXTENDS FROM T.D. DEBBY TO 22N54W. A HIGH PRESSURE LOCATED NEAR THE AZORES EXTENDS A RIDGE OVER THE CENTRAL-EAST ATLC EAST OF 45W. $$ GR