000 AXNT20 KNHC 100522 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 205 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 0500 UTC. ...SPECIAL FEATURE... 1005 MB LOW IS IN THE NW CARIBBEAN NEAR 19N85W DRIFTING NORTHWARD. THERE IS NO WELL-DEFINED CIRCULATION CENTER AS OF YET BUT THE SYSTEM STILL SHOWS SIGNS OF BANDING FEATURES AND LARGE (3-4 MB) 24 HOUR PRESSURE FALLS. THE SYSTEM IS CLOSE TO BECOMING A TROPICAL DEPRESSION AND ALL SIGNS GENERALLY POINT TO IT DEVELOPING LATER TODAY. COMPUTER MODEL GUIDANCE ROUGHLY TAKE THE SYSTEM IN A NORTHWESTERLY DIRECTION TOWARD THE YUCATAN CHANNEL AND INTO THE SOUTHERN GULF OF MEXICO BY ABOUT THIS TIME TOMORROW. AN UPPER TROUGH TO THE W OF THE CYCLONE HAS BEEN GRADUALLY MOVING WESTWARD WITH AN EXPANSION OF AN UPPER ANTICYCLONE CENTERED NEAR 18N83W. 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 MODERATE CONVECTION IS FROM 17N-21N BETWEEN JAMAICA AND 85W. ...TROPICAL WAVES... TROPICAL WAVE IS ALONG 32W S OF 11N MOVING W 15 KT. THE WAVE HAS A PRETTY GOOD V-SIGNATURE ON NIGHTTIME VISIBLE SATELLITE ALONG WITH SOME SCATTERED MODERATE TSTMS IN THE ITCZ WITHIN 90 NM OF 7N34W. TROPICAL WAVE IS ALONG 57W/58W 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. TROPICAL WAVE IS ALONG 70W/71W S OF 10N MOVING W 10 KT. WAVE IS FAIRLY LOW-LATITUDE WITH NO SIGNIFICANT WEATHER OVER WATER. A FEW TSTMS ARE INLAND OVER COLOMBIA/NW VENEZUELA ASSOCIATED WITH THE WAVE. TROPICAL WAVE IS ALONG 81W 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 6N25W 5N45W 7N58W. WIDELY SCATTERED MODERATE CONVECTION WITHIN 45 NM OF LINE 8N37W 5.5N45W 7N53W AND S OF 4.5N W OF 48W. ISOLATED MODERATE CONVECTION S OF 5N BETWEEN 33W-37W. SCATTERED MODERATE CONVECTION IS FROM 4N-7N BETWEEN 21W-27W. AND WITHIN 60 NM OF 9.5N18W. ...DISCUSSION... GULF OF MEXICO... UPPER RIDGING COVERS THE NORTHERN GULF WITH A CENTER JUST S OF SE LOUISIANA. MODERATE/STRONG SUBSIDENCE IS CONTROLLING THE REGION N AND W OF AN UPPER TROUGH EXTENDING FROM SW FLORIDA TO 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 TOMORROW AND MUCH HIGHER FOR SUN. THE NORTHERN GULF COAST WEST 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 1005 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. UPPER CONVERGENCE IS LEADING TO A DRY WEATHER PATTERN OVER THE EASTERN CARIBBEAN WITH ONLY A FEW TSTMS IN THE SW CARIBBEAN AND ALONG THE NW COAST OF COLOMBIA. 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 70W 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 ST LUCIA 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 20N22W.. MUCH FARTHER N THAN AVERAGE FOR EARLY JUNE. RIDGE AXIS EXTENDS TO 19N30W 8N40W 8N80W.. 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 ... SHIFTING EASTWARD FROM THE EASTERN PACIFIC INTO THE ATLC DURING THE NEXT WEEK OR SO. $$ BLAKE