000 AXNT20 KNHC 101052 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 805 AM EDT SAT JUN 10 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1040 UTC. ...SPECIAL FEATURE... 1003 MB LOW IS IN THE NW CARIBBEAN AT 0900 UTC NEAR 20.5N85W MOVING NW 5 KT. SURFACE OBSERVATIONS INDICATE THE LOW HAS PASSED BUOY 42056 AS IT REPORTED LIGHT SW WINDS AT 0700 UTC AND A RATHER LOW PRESSURE. NIGHT VIS IMAGES ARE SUGGESTING THAT A LOW-LEVEL CENTER HAS EITHER MOVED NORTHWARD OR HAS REFORMED TO THE W OF A LARGE BURST OF CONVECTION. THE SYSTEM COULD BECOME A TROPICAL DEPRESSION OR TROPICAL STORM AT ANY TIME. COMPUTER MODELS GENERALLY MOVE THE SYSTEM NORTHWESTERLY THRU THE YUCATAN CHANNEL INTO THE SOUTHERN GULF OF MEXICO BY LATE TONIGHT. AN UPPER TROUGH TO THE W OF THE CYCLONE HAS BEEN GRADUALLY MOVING WESTWARD WITH A LITTLE EXPANSION OF A UPPER ANTICYCLONE CENTERED NEAR 18N83W. HOWEVER VERTICAL WIND SHEAR IS MARGINAL FOR DEVELOPMENT AS THE UPPER TROUGH IS STILL IMPARTING SW WINDS OVER THE CIRCULATION CENTER. FOR NOW.. THE PRIMARY THREAT IS CONTINUED HEAVY RAINS OVER THE CAYMAN ISLANDS AND CENTRAL CUBA WESTWARD AS SOME OF THOSE AREAS HAVE RECEIVED OVER 8 INCHES OF RAIN. SCATTERED BANDS OF TSTMS ARE MOSTLY TO THE E OF THE SYSTEM WITH STRONG CONVECTION NOW FROM 18N-CUBA BETWEEN 80W-85W AND MORE MODERATE CONVECTION FROM 17N-19N BETWEEN 81W-84W WITH A FEW TSTMS REMAINING IN THE GULF OF HONDURAS. ...TROPICAL WAVES... TROPICAL WAVE IS ALONG 34W S OF 15N MOVING W 15-20 KT. THIS IS A LARGE WELL-DEFINED WAVE WITH A V-SHAPE IN BOTH THE LOW AND MIDDLE LEVEL CLOUDS. ISOLATED MODERATE CONVECTION IS S OF 8N BETWEEN 34W-37W. TROPICAL WAVE IS ALONG 59W S OF 9N MOVING W 10-15 KT. ANY SIGNIFICANT WEATHER WITH THE WAVE IS INLAND OVER NORTHERN S AMERICA. COMPUTER MODELS SUGGEST THAT MOISTURE WITH THE WAVE SHOULD STAY S OF THE WINDWARD ISLANDS SAVE PERHAPS TRINIDAD. TROPICAL WAVE IS ALONG 72W S OF 10N MOVING W 10-15 KT. WAVE IS FAIRLY LOW-LATITUDE WITH NO SIGNIFICANT WEATHER OVER WATER. SOME TSTMS OVER NW COLOMBIA ARE PROBABLY ASSOCIATED WITH THE WAVE. TROPICAL WAVE IS ALONG 82W/83W S OF 13N MOVING W 10 KT. THE SOUTHERN EXTENSION OF THE WAVE IS PRODUCING SHOWERS/TSTMS OVER COSTA RICA AND PANAMA. ITCZ... ITCZ AXIS IS CENTERED ALONG 10N14W 5N25W 8N35W 5N47W 7N58W. SCATTERED MODERATE CONVECTION FROM 4N-6N BETWEEN 24W-28W. A FEW TSTMS ARE WITHIN 90 NM OF 9N20W. WIDELY SCATTERED MODERATE WITHIN 60 NM OF AXIS W OF 40W AND S OF AXIS BETWEEN 48W AND S AMERICA. ...DISCUSSION... GULF OF MEXICO... UPPER RIDGING COVERS THE NORTHERN GULF WITH A CENTER JUST S OF SE LOUISIANA. ASSOCIATED WEAK SURFACE RIDGING IS ALONG 28N IN THE GULF.. PROVIDING WLY WINDS AND RECORD HEAT TO PORTIONS OF THE NORTHERN GULF COAST. DEWPOINTS ARE CONSIDERABLY LOWER THAN AVERAGE AS THE TYPICAL SUMMERTIME SLY LOW-LEVEL WINDS HAVEN'T STARTED. MODERATE/STRONG SUBSIDENCE IS CONTROLLING THE REGION N AND W OF AN UPPER TROUGH EXTENDING FROM SW FLORIDA TO JUST W OF THE YUCATAN PENINSULA. THIS UPPER TROUGH IS MOVING SLOWLY WESTWARD AS UPPER RIDGING POKES INTO THE SE GULF OF MEXICO. AS THE TROUGH SLIDES WESTWARD.. IT SHOULD ALLOW DEEP TROPICAL MOISTURE IN ASSOCIATION WITH THE TROPICAL DISTURBANCE IN THE NW CARIBBEAN TO SPREAD NORTHWARD... INCREASING THE THREAT OF RAIN FOR S FLORIDA TODAY AND MUCH HIGHER FOR SUN...PERHAPS ALL OF FLORIDA FOR MON. THE NORTHERN GULF COAST W OF LOUISIANA LOOKS QUITE DRY FOR THIS TIME OF THE YEAR THOUGH RAIN CHANCES MIGHT BE ON THE INCREASE IN THE EASTERN GULF BY EARLY NEXT WEEK. CARIBBEAN SEA... THE MAIN WEATHER INTEREST IN THIS AREA IS A 1003 MB LOW IN THE NW CARIBBEAN THAT IS PRODUCING WIDESPREAD CLOUDINESS AND SHOWERS OVER THE REGION AND ADJACENT LAND AREAS. SEE SPECIAL FEATURE FOR DETAILS. UPPER RIDGE AXIS EXTENDS FROM NEAR JAMAICA EASTWARD TO JUST N OF PUERTO RICO WITH ELY WINDS ALOFT OVER THE CARIBBEAN SAVE FOR A SMALL AREA OF UPPER TROUGHING IN THE FAR SE WINDWARD ISLANDS. LOW-LEVEL CONVERGENCE BETWEEN THE SLY FLOW FROM THE TROPICAL SYSTEM AND ELY FLOW FROM THE ATLC RIDGE IS ENHANCING SCATTERED MODERATE CONVECTION NW OF COLOMBIA FROM 9.5N-12.5N BETWEEN 76W-79W. ELSEWHERE UPPER CONVERGENCE IS LEADING TO A DRY WEATHER PATTERN OVER THE EASTERN CARIBBEAN. THE GFS INCREASES THE DEEP-LAYERED MOISTURE SOME IN THE NE CARIBBEAN BY LATE SUN WHICH COULD PROVOKE A FEW MORE SHOWERS/TSTMS IN THAT AREA. NEXT SIGNIFICANT WAVE IS FORECAST TO ENTER THE E CARIBBEAN EARLY TUE AND MIGHT BE THE MOST CONVECTIVELY-ACTIVE OF THE SEASON SO FAR. ATLANTIC OCEAN... UPPER TROUGH NOSES INTO THE NW PART OF THE AREA ALONG 68W N OF 27N INCREASING THE NUMBER OF MID/UPPER CLOUDS N OF 27N ALONG WITH A FEW SHOWERS. LARGE MID-OCEANIC TROUGH IS SITTING FROM 31N41W 14N50W THEN INTO THE WINDWARD ISLANDS NEAR BARBADOS WITH A MID/UPPER LOW NEAR 26N45W ALONG THE TROUGH. MODERATE/STRONG SUBSIDENCE CONTROLS MUCH OF THE REGION WITHIN ABOUT 300 NM OF THE TROUGH EXCEPT FOR ISOLATED SHOWERS/TSTMS WITHIN 120 NM OF THE LOW CENTER... WHICH HAS A WEAK SURFACE TROUGH REFLECTION. IN THE E ATLC.. HIGH PRESSURE HAS BUILT UP IN THE MID/UPPER LEVELS WITH A CENTER NEAR 19N24W.. MUCH FARTHER N THAN AVERAGE FOR EARLY JUNE. RIDGE AXIS EXTENDS TO 19N33W 9N40W 7N60W.. FARTHER S THAN AVERAGE IN THE CENTRAL ATLC. THIS UPPER PATTERN IS FAVORABLE TO SUPPORT A FAIR NUMBER OF TSTMS IN THE ITCZ AND SOMEWHAT CONVECTIVE WAVES. TYPICAL STRATOCUMULUS DECK COVERS THE CENTRAL/E ATLC WITH THE SUBTROPICAL RIDGE IN CONTROL.. ALBEIT A TAD WEAKER THAN AVERAGE. COMPUTER MODELS SUGGEST THAT THE NEXT FEW WAVES WILL BE FAIRLY STRONG WITH A MUCH FARTHER NORTHWARD EXTENT THAN THE RECENT BATCH W OF 50W. THIS IS POSSIBLY DUE TO A LARGE-SCALE DIVERGENCE PATTERN ... SOMEWHAT RELATED TO THE MADDEN-JULIAN OSCILLATION ... BEING OVERHEAD FOR THE NEXT WEEK OR SO. $$ BLAKE