000 AXNT20 KNHC 271749 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 205 PM EDT TUE JUN 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1715 UTC. ...SPECIAL FEATURES... SATELLITE AND RADAR INFORMATION CONTINUE TO INDICATE THAT A SMALL LOW PRESSURE SYSTEM COULD BE FORMING ABOUT 140 MILES SOUTH- SOUTHWEST OF CAPE LOOKOUT NORTH CAROLINA. THIS SYSTEM HAS BECOME BETTER ORGANIZED THIS MORNING...AND POTENTIAL REMAINS FOR IT TO DEVELOP INTO A TROPICAL DEPRESSION OR A TROPICAL STORM AT ANY TIME AS THE SYSTEM MOVES NORTH TO NORTH-NORTHEASTWARD AT ABOUT 20 MPH. AN AIR FORCE RESERVE RECONNAISSANCE AIRCRAFT IS INVESTIGATED THE SYSTEM TO DETERMINE IF A CLOSED CIRCULATION EXISTS AT THE SURFACE. AREA OF SCATTERED MODERATE/ISOLATED STRONG CONVECTION COVERS THE AREA FROM 30.5N-35W BETWEEN 75.5W-78.5W AND ACROSS PORTIONS OF THE OUTER BANKS IN NORTH CAROLINA. EVEN IF THIS SYSTEM DOES NOT FORM INTO A TROPICAL CYCLONE...SHOWERS AND THUNDERSTORMS PRODUCING LOCALLY HEAVY RAINFALL AND STRONG GUSTY WINDS WILL GRADUALLY SPREAD ONSHORE THE NORTH CAROLINA AND VIRGINIA COASTS TODAY AND TONIGHT. ...TROPICAL WAVES... TROPICAL WAVE IS ALONG 37W/38W S OF 12N MOVING W 10 KT. LOW-AMPLITUDE WAVE IS WELL-DEFINED ON SATELLITE IMAGERY. SHOWER OR CONVECTION ACTIVITY IS WITHIN THE ITCZ. A LARGE TROPICAL WAVE ACCOMPANIED BY A WEAK 1013 MB LOW PRESSURE AREA IS ALONG 50W/51W S OF 15N OR ABOUT 550 MILES EAST OF THE SOUTHERN WINDWARD ISLANDS. CLUSTERS OF MODERATE TO STRONG CONVECTION ARE ASSOCIATED WITH THE LOW. A DEVELOPMENT OF THIS SYSTEM...IF ANY...IS EXPECTED TO BE SLOW TO OCCUR AS THE WAVE CONTINUES WEST-NORTHWESTWARD AT ABOUT 20 MPH. SHOWERS AND A FEW TSTMS ACCOMPANIED BY BRIEF HEAVY RAINFALL AND GUSTY WINDS WILL AFFECT THE LESSER ANTILLES ON WEDNESDAY. THIS WAVE IS EXPECTED TO REACH THE VIRGIN ISLANDS AND PUERTO RICO ON THURSDAY... INCREASING THE CHANCES OF RAIN AND THE RISK OF FLASH FLOODING OVER THAT AREA. TROPICAL WAVE IS ALONG 85W S OF 22N MOVING W 10-15 KT. WEAK LOW LEVEL SIGNATURE CURVATURE IS OBSERVED ON SATELLITE IMAGERY DUE TO THE WAVE IS BENEATH THE W PORTION OF A BROAD UPPER RIDGE THAT IS OVER THE CARIBBEAN. CLUSTERS OF MODERATE TO STRONG CONVECTION ARE OVER THE SW CARIBBEAN...THE EASTERN PORTION OF NICARAGUA... THE GULF OF HONDURAS AND BELIZE. SHOWERS WITH EMBEDDED TSTMS ARE ALSO AFFECTING THE WESTERN PORTION OF CUBA...INCLUDING THE ISLE OF YOUTH. THE TROPICAL WAVE AND A DIFFLUENT PATTERN ALOFT ARE ENHANCING THIS CONVECTIVE ACTIVITY. ...THE ITCZ... ITCZ AXIS IS CENTERED ALONG 10N15W 7N25W 7N35W 7N40W 9N49W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS WITHIN 120/150 NM S OF THE AXIS BETWEEN 20W-33W. SIMILAR CONVECTION IS WITHIN 120 NM N OF THE AXIS WEST OF 53W AND ALONG THE COAST OF GUYANA AND NE VENEZUELA. ...DISCUSSION... GULF OF MEXICO... BROAD DEEP LAYERED TROUGH EXTENDS FROM THE UPPER MISSISSIPPI VALLEY INTO THE CENTRAL GULF WHILE A SHORT WAVE TROF IS OVER WEST FLORIDA...THE SE GULF AND THE YUCATAN CHANNEL. THIS FEATURE IS SUPPORTING THE DEVELOPMENT OF SCATTERED/NUMEROUS SHOWERS AND TSTMS OVER NORTH-CENTRAL FLORIDA. AN UPPER RIDGE OVER MEXICO EXTENDS OVER THE BAY OF CAMPECHE. AT THE SURFACE...WEAK HIGH PRESSURE IS KEEPING RATHER QUIET CONDITIONS ACROSS THE GULF WITH LIGHT WINDS. A SURFACE TROUGH RUNS FROM THE FLORIDA PANHANDLE TO NEAR 27N91W. ISOLATED SHOWERS/THUNDERSTORMS ARE OVER THE NE QUADRANT OF THE GULF AND NORTHERN FLORIDA ASSOCIATED WITH THE TROUGH. CARIBBEAN SEA... BROAD UPPER RIDGE COVERS THE W CARIBBEAN WITH THE AXIS EXTENDING NEWD ACROSS EASTERN CUBA...THE BAHAMAS AND THE W ATLC WEST OF 70W. TROPICAL MOISTURE IS BEING ADVECTED OVER CENTRAL AMERICA AND THE NW CARIBBEAN. AN UPPER TROUGH THAT EXTENDS MAINLY SOUTH FROM THE W ATLC OVER PUERTO RICO AND THE EASTERN CARIBBEAN IS GENERATING SCATTERED SHOWERS AND ISOLATED TSTMS OVER THE WINDWARD ISLANDS. PRESSURE GRADIENT BETWEEN THE ATLC HIGH AND THE COLOMBIAN LOW IS PRODUCING MODERATE TO STRONG TRADE WINDS OFF THE COLOMBIA COAST. EARLIER QUIKSCAT PASS SHOWS WINDS OF 20-25 KT. ATLANTIC OCEAN... AN UPPER RIDGE COVERS THE W ATLC WEST OF 70W. A DEEP LAYERED TROUGH PERSISTS OVER THE CENTRAL ATLC. THIS UPPER TROUGH IS N OF 22N FROM 50W-70W WITH AN UPPER LOW NEAR 31N56W. A SURFACE TROUGH EXTENDS ALONG 31N50W 25N60W TO 21N68W. SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS ARE WITHIN AROUND 100 NM E AND S OF THE TROUGH FROM 46W-58W AND WITHIN 50N N OF THE TROUGH FROM 58W-62W. AN LARGE UPPER HIGH IN THE TROPICAL ATLC IS LOCATED NEAR 12N38W WITH AN UPPER RIDGE COVERING MOST OF THE TROPICS. AT THE SURFACE...BROAD HIGH PRESSURE COVERS MOST OF THE ATLC ANCHORED BY 1036 MB HIGH NW OF THE AZORES. TYPICAL STRATOCUMULUS CLOUDS ARE EAST OF THE AFOREMENTIONED SURFACE TROUGH. ACCORDING TO THE 27/1500 UTC CIMSS SAHARAN AIR LAYER A BROAD AREA OF AFRICAN DUST COVERS THE E ATLC EAST OF 40W. $$ GR