000 AXNT20 KNHC 141027 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 805 AM EDT THU SEP 14 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 0345 UTC. ...SPECIAL FEATURES... HURRICANE GORDON IS CENTERED NEAR 28.7N 56.6W AT 14/0900 UTC MOVING NORTH-NORTHEAST AT 11 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 955 MB. MAXIMUM SUSTAINED WIND SPEED IS 105 KT WITH GUSTS TO 130 KT. SEE THE LATEST NHC FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT2/WTNT22 KNHC FOR MORE DETAILS. GORDON STILL HAS A SMALL VERY DISTINCT EYE WITH UNIFORM CONVECTION SURROUNDING THE EYE. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS WITHIN 90 NM FROM THE CENTER IN ALL QUADRANTS. SCATTERED MODERATE CONVECTION CONTINUES WITHIN 150 NM OF THE CENTER IN THE N QUADRANT AND WITHIN 200 NM IN THE E QUADRANT. TROPICAL STORM HELENE IS CENTERED NEAR 13.7N 34.7W AT 14/0900 MOVING WEST AT 19 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 1005 MB. MAXIMUM SUSTAINED WIND SPEED IS 35 KT WITH GUSTS TO 45 KT. SEE THE LATEST NHC FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT3/WTNT23 KNHC FOR MORE DETAILS. HELENE REMAINS FAIRLY UNORGANIZED DESPITE THE WIND SPEED INCREASE. THE DEEPEST CONVECTION IS REMOVED FROM THE CENTER. CLUSTERS OF SCATTERED MODERATE/STRONG CONVECTION COVER A BROAD AREA FROM 8N-19N BETWEEN 26W-39W. ...TROPICAL WAVES... TROPICAL WAVE IS ALONG 46W S OF 13N MOVING W 10-15 KT. LOW AMPLITUDE WAVE EMBEDDED WITHIN A LAYER OF AFRICAN DUST THUS NO ASSOCIATED CONNECTION. TROPICAL WAVE IS ALONG 54W/55W S OF 14N MOVING W 10-15 KT. WEAK WAVE SIGNATURE AS THE WAVE MOVES TOWARD AN AREA OF UPPER DIFFLUENCE THAT EXTENDS NE OF THE LESSER ANTILLES. ASSOCIATED CONVECTION IS WITHIN THE ITCZ. TROPICAL WAVE IS ALONG 64W/65W S OF 18N MOVING W 15 KT. WELL-DEFINED LOW LEVEL INVERTED-V SATELLITE SIGNATURE IS OBSERVED OVER THE E CARIBBEAN. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS FROM 14N18N BETWEEN 63W-66W. TROPICAL WAVE IS ALONG 74W/75W S OF 18N MOVING W 15 KT. WEAK LOW LEVEL INVERTED-V SATELLITE SIGNATURE IS OBSERVED OVER THE CENTRAL CARIBBEAN. WAVE IS EMBEDDED WITHIN VERY DRY AIR THUS NO ASSOCIATED CONVECTION. ...THE ITCZ... ITCZ AXIS IS CENTERED ALONG 14N16W 13N26W 14N31W THEN ALONG 10N35W 8N44W 12N62W ACROSS THE N PORTION OF SOUTH AMERICA AND PANAMA NEAR 9N83W INTO THE E PACIFIC REGION. SCATTERED MODERATE/STRONG CONVECTION IS WITHIN 150 NM S OF THE AXIS FROM 17W-27W AND WITHIN 150 NM N OF THE AXIS E OF 22W TO THE COAST OF AFRICA. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS FROM 6N-10N BETWEEN 47W-53W AND SCATTERED MODERATE CONVECTION IS WITHIN 60 NM OF THE AXIS FROM 55W-58W. ...DISCUSSION... GULF OF MEXICO... BROAD DEEP LAYERED TROUGH COVERS THE E US AND ALONG THE N GULF COAST ANCHORED BY AN UPPER LOW MOVING JUST S OF THE GREAT LAKES REGION. THE ASSOCIATED FRONTAL BOUNDARY EXTENDS INTO THE GULF THROUGH A 1009 MB LOW OVER THE FLORIDA PANHANDLE NEAR TALLAHASSEE SW TO 28N86W WHERE IT BECOMES NEAR STATIONARY THE TEXAS/MEXICO BORDER. ISOLATED SHOWERS ARE OVER THE N GULF N OF THE FRONT E OF 90W. UPPER RIDGE EXTENDS ACROSS THE REMAINDER OF THE GULF ANCHORED BY AN UPPER HIGH OVER CENTRAL MEXICO ACROSS TAMPICO MEXICO TO JUST S OF TAMPA FLORIDA INTO THE W ATLC. THIS IS GENERATING SCATTERED SHOWERS/ISOLATED THUNDERSTORMS FROM 24N-28N E OF 84W TO INLAND OVER S FLORIDA AND SCATTERED SHOWERS FROM 23N-27N W OF 94W TO INLAND OVER NE MEXICO. MID LEVEL LOW IS IN THE SW GULF NEAR 21N94W GENERATING ISOLATED SHOWERS S OF 21N INTO THE BAY OF CAMPECHE W OF 93W TO OVER MEXICO. CARIBBEAN SEA... W CARIBBEAN IS DOMINATED BY NE UPPER FLOW FROM THE UPPER RIDGE THAT EXTENDS ACROSS THE GULF OF MEXICO INTO THE W ATLC. THIS IS PROVIDING DRY AIR ACROSS THE AREA INCLUDING THE TROPICAL WAVE ALONG 74W/75W. AN UPPER TROUGH EXTENDS FROM THE W ATLC ACROSS HISPANIOLA TO CENTRAL COSTA RICA. E CARIBBEAN IS DOMINATED BY S UPPER FLOW FROM AN UPPER RIDGE ANCHORED IN THE TROPICAL ATLC. THIS RIDGE IS DRAWING ABUNDANT TROPICAL MOISTURE ACROSS THE E CARIBBEAN AND ENHANCING CONVECTION ASSOCIATED WITH THE TROPICAL WAVE ALONG 64W/65W AND GENERATING SCATTERED SHOWERS/ISOLATED THUNDERSTORMS OVER THE NE CARIBBEAN N OF 16N E OF 64W INCLUDING THE VIRGIN AND N LEEWARD ISLANDS. CLUSTERS OF SCATTERED MODERATE/ISOLATED STRONG CONVECTION ARE WITHIN 90 NM ALONG THE COAST OF COLOMBIA AND PANAMA DUE TO THE PROXIMITY OF THE ITCZ AXIS. ATLANTIC OCEAN... BROAD DEEP LAYERED TROUGH THAT COVERS THE E US AND THE N GULF COAST ANCHORED BY AN UPPER LOW MOVING JUST S OF THE GREAT LAKES REGION AND IS EXTENDING INTO THE NW ATLC. THE ASSOCIATED FRONTAL BOUNDARY EXTENDS INTO THE GULF IS APPROACHING THE SE US COAST GIVING THE AREA SCATTERED SHOWERS/ISOLATED THUNDERSTORMS N OF 28N FROM 77W-80W. UPPER RIDGE AXIS EXTENDS FROM THE GULF OF MEXICO INTO THE W ATLC ACROSS FLORIDA JUST S OF DAYTONA BEACH TO NEAR 31N68W. BENEATH THIS UPPER RIDGE IS A SURFACE TROUGH THAT EXTENDS FROM 32N71W THROUGH A 1010 MB LOW NEAR 28N73W ACROSS THE CENTRAL BAHAMAS TO NEAR 24N78W. THIS IS GENERATING SCATTERED SHOWERS/ISOLATED THUNDERSTORMS NE OF THE LOW FROM 27N-32N BETWEEN 68W-73W. AN UPPER LOW IS IN THE W ATLC JUST TO THE E OF THE RIDGE NEAR 24N68W WITH THE UPPER TROUGH EXTENDING S ACROSS HISPANIOLA INTO THE CARIBBEAN GENERATING SCATTERED SHOWERS FROM 23N-29N BETWEEN 62W-70W. BROAD UPPER RIDGE COVERS THE W/CENTRAL ATLC ANCHORED IN THE TROPICS NEAR 18N57W COVERING THE AREA S OF 25N FROM 46W-66W. ABUNDANCE OF TROPICAL MOISTURE IS BEING DRAWN ACROSS THE E CARIBBEAN AND WITH SUFFICIENT DIFFLUENCE TO GENERATE AN AREA OF SCATTERED SHOWERS/THUNDERSTORMS FROM 14N-21N BETWEEN 55W-64W. GORDON IS N OF THIS UPPER RIDGE. AN UPPER TROUGH EXTENDS INTO THE CENTRAL ATLC NEAR 32N42W S TO 22N45W. HOWEVER...DUE TO THE DRY AIR IN PLACE NO SHOWER ACTIVITY IS EVIDENT. BROAD UPPER RIDGE COVERS THE REMAINDER OF THE ATLC E OF 32W ANCHORED NEAR 28N28W EXTENDING E TO OVER THE CANARY ISLANDS AND NW AFRICA. AT THE SURFACE...A RIDGE COVERS THE ATLC N OF 20N E OF 50W WITH A 1028 MB HIGH SE OF THE AZORES. THE FIRST VISIBLE SATELLITE IMAGES SHOWS A LARGE AREA OF AFRICA DUST FROM THE ITCZ TO 30N BETWEEN 35W-50W WITH HELENE JUST TO THE E OF THIS DUST. $$ WALLACE