000 AXNT20 KNHC 040530 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 205 AM EDT FRI JUL 04 2008 TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL AMERICA...GULF OF MEXICO...CARIBBEAN SEA...NORTHERN SECTIONS OF SOUTH AMERICA...AND 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 0515 UTC. ...SPECIAL FEATURE.... TROPICAL STORM BERTHA CENTERED NEAR 13.4N 27.0W AT 0300 UTC OR ABOUT 160 NM WSW OF THE SOUTHERNMOST CAPE VERDE ISLANDS MOVING W AT 12 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 1006 MB. MAXIMUM SUSTAINED WIND SPEED IS 35 KT WITH GUSTS TO 45 KT. SEE LATEST NHC FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT2/WTNT42 KNHC FOR MORE DETAILS. BERTHA IS PULLING AWAY FROM THE CAPE VERDE ISLANDS. LITTLE IMPACT WAS AFFECTED NEAR SAL ON THU AS SFC REPORTS SHOW MAX WINDS JUST OVER 20 KT...A PRESSURE OF 1012 MB AND VERY LITTLE RAINFALL. MORE OF AN IMPACT WAS LIKELY FELT OVER THE SOUTHERN ISLANDS CLOSER TO THE CORE OF COMPACT BERTHA. BERTHA MAINTAINS A WELL DEFINED CIRCULATION WITH A TIGHT AREA OF NUMEROUS MODERATE TO STRONG CONVECTION MAINLY LOCATED WITHIN 90 NM N/NE OF THE CENTER. STRENGTHENING IS FORECAST IN THE SHORT TERM AS ATMOSPHERIC CONDITIONS APPEAR FAVORABLE AND OCEANIC CONDITIONS ARE MARGINAL. ...TROPICAL WAVES... TROPICAL WAVE IS TILTED ALONG 50W/51W S OF 20N MOVING W 20 KT. DESPITE THE HIGH AMPLIFICATION OBSERVED IN SATELLITE IMAGERY AND SCATTEROMETER DATA...THERE IS MINIMAL ASSOCIATED CONVECTION. SHALLOW SCATTERED SHOWERS ARE WITHIN 240 NM EITHER SIDE OF THE AXIS. THE LOW AMPLITUDE TROPICAL WAVE PREVIOUSLY ANALYZED NEAR 60W HAS BEEN DROPPED FROM THE SFC ANALYSIS. THERE HAS BEEN LITTLE EVIDENCE OF THIS FEATURE OVER THE PAST SEVERAL DAYS AND IT APPEARS THAT MUCH OF ITS MOISTURE/ENERGY HAS BEEN DRAWN INTO THE ITCZ...DUE TO THE ENHANCED NE FLOW ON THE W SIDE OF THE LARGE WAVE TO ITS E. TROPICAL WAVE IS OVER THE CENTRAL CARIBBEAN ALONG 69W S OF 18N MOVING W 15-20 KT. A VORTICITY MAXIMUM REMAINS LOCATED ALONG THE AXIS NEAR 15N. DISORGANIZED SCATTERED SHOWERS AND TSTMS ARE NEAR THIS ENHANCED AREA OF CYCLONIC TURNING FROM 14N-16N BETWEEN 67W-69W. UPPER WINDS ARE NOT CONDUCIVE FOR FURTHER DEVELOPMENT. TROPICAL WAVE IS OVER THE WESTERN CARIBBEAN ALONG 81W S OF 15N MOVING W 15 KT. THIS WAVE LIES IN AN UPPER DIFFLUENT ZONE ON THE S SIDE OF AN UPPER HIGH...TRIGGERING SCATTERED SHOWERS AND TSTMS FROM 12N-16N BETWEEN 79W-84W. ...ITCZ... ITCZ AXIS IS CENTERED ALONG 16N17W 15N23W 10N29W 8N40W 5N48W 7N59W. SCATTERED MODERATE CONVECTION IS FROM 6N-10N BETWEEN 27W-32W AND FROM 4N-6N BETWEEN 36W-40W. SCATTERED MODERATE TO STRONG CONVECTION IS FROM 7N-11N E OF 16W. ...DISCUSSION... THE GULF OF MEXICO... THE LARGE SCALE PATTERN CONSISTS OF AN ELONGATED UPPER TROUGH EXTENDING SW ACROSS THE EAST AND CENTRAL WATERS...AN UPPER LOW SPINNING OVER SOUTH TEXAS AND BROAD RIDGING LIES OVER CENTRAL MEXICO. THIS PATTERN IS KEEPING A FAIR AMOUNT OF MOISTURE OVER THE REGION. HOWEVER...LIGHTNING DATA INDICATES THAT LITTLE OF THIS IS LEADING TO SIGNIFICANT TSTM ACTIVITY OVER THE CENTRAL AND EASTERN WATERS. THERE IS SCATTERED SHOWERS AND TSTMS NEAR THE COAST OF MEXICO AND SOUTH TEXAS S OF 27N W OF 96W MAINLY ASSOCIATED WITH THE DIFFLUENT PATTERN MENTIONED ABOVE. AT THE SFC...ATLC RIDGING EXTENDS ACROSS THE ALONG 28N ALLOWING WINDS TO BE LIGHT ACROSS THE N WATERS AND MODERATE TO FRESH OVER THE S WATERS. THE CARIBBEAN SEA... A PAIR OF TROPICAL WAVES ARE PROPAGATING ACROSS THE SEA. THE EASTERN ONE (APPROACHING 70W) HAS BEEN FAIRLY WELL DEFINED OVER THE PAST COUPLE OF DAYS...HOWEVER...IT APPEARS LESS ORGANIZED TONIGHT AS ONLY A SMALL AREA OF SCATTERED SHOWERS/TSTMS EXIST FROM 14N-16N BETWEEN 67W-69W. THE OTHER WAVE ALONG 81W HAS BEEN FAIRLY INACTIVE OVER THE PAST COUPLE OF DAYS BUT IT HAS GAINED CONVECTION TONIGHT AS IT TRACKED INTO AN UPPER DIFFLUENT AREA. REFER TO THE TROPICAL WAVE SECTION ABOVE FOR MORE DETAILS. ELSEWHERE...DEEP CONVECTION IS FAIRLY MINIMAL AT THE MOMENT DESPITE A MOIST ENVIRONMENT ALOFT. HOWEVER...ITS QUITE A DIFFERENT STORY OVER EL SALVADOR...GUATEMALA...WRN HONDURAS AND BELIZE...WHERE NUMEROUS SHOWERS AND TSTMS ARE OCCURRING IN ASSOCIATED WITH THE UPPER DIFFLUENT ZONE AND SOME INFLUENCE FROM A DISTURBANCE IN THE EAST PACIFIC NEAR 11N95W. THE ATLANTIC OCEAN... THE UPPER PATTERN REMAINS DIFFLUENT OVER THE W ATLC BETWEEN ELONGATED TROUGHING OVER THE EASTERN SEABOARD OF THE U.S. AND A NARROW RIDGE E OF THE BAHAMAS ALONG 70W. THIS PATTERN IS PRODUCING ABUNDANT CLOUDINESS AND EMBEDDED SCATTERED SHOWERS AND TSTMS OVER THE NW BAHAMAS AND NEARBY WATERS N OF 25N W OF 77W. FARTHER E...A LARGE UPPER LOW IS SPINNING NEAR 32N53W WITH TROUGHING EXTENDING S TOWARDS THE NE CARIBBEAN. LARGE SCALE RIDGING HOLDS E OF THERE WITH AN UPPER HIGH POSITIONED NEAR 20N44W. OVERALL...THIS PATTERN IS PRODUCING LITTLE SENSIBLE WEATHER BESIDES FOR SCATTERED SHOWERS AND TSTMS NEAR THE UPPER LOW N OF 29N BETWEEN 43W-59W. AT THE SFC...A PAIR OF QUASI-STATIONARY HIGHS ARE OVER THE CENTRAL ATLC...ONE ANALYZED 1028 MB NEAR 34N41W...THE OTHER 1026 MB HIGH NEAR 34N61W. A SFC TROUGH IS WEAKENING THE RIDGE FROM 23N50W TO 31N46W. THIS TROUGH APPEARS TO BE PARTLY ASSOCIATED WITH THE LARGE TROPICAL WAVE TO THE S AND THE UPPER LOW CENTERED TO THE NW. SCATTERED LOW-LEVEL SHOWERS ARE WITHIN 180 NM OF THE AXIS. $$ CANGIALOSI