000 AXNT20 KNHC 211742 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 205 PM EDT SUN MAY 21 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. ...TROPICAL WAVES... TROPICAL WAVE IS ALONG 27W/28W S OF 7N MOVING W 15 KT. WAVE IS NOT WELL-DEFINED IN AVAILABLE SATELLITE IMAGERY WHICH SUGGEST A BROAD AREA OF TURNING AND NO OBVIOUS WAVE AXIS. THE CONVECTION DOES NOT SEEM TO BE WELL-MATCHED TO THE BEST TURNING IN THE LOW/MID-LEVELS. HOWEVER THE GFS MODEL SUGGESTS THIS WAVE WILL BE HAVE A FAIR NUMBER OF TSTMS WITH FAVORABLE UPPER DIFFLUENCE THOUGH LIKELY REMAINING BROAD AS WELL. SCATTERED MODERATE FROM 1N-4.5N BETWEEN 23W-28.5W. TROPICAL WAVE IS ALONG 53W/54W S OF 7N MOVING W 15-20 KT. THERE IS SOME HINT OF THE WAVE IN THE CUMULUS CLOUD FIELD OVER S AMERICA WITH BROAD CYCLONIC FLOW... OTHERWISE THE WAVE IS BECOMING VERY HARD TO TRACK. ISOLATED TSTMS OVERLAND N OF 1N E OF 56W. TROPICAL WAVE PREVIOUSLY ALONG 87W HAS LEFT THE AREA. ...ITCZ... ITCZ AXIS IS CENTERED ALONG 9N12W 1N40W 3.5N51W. WIDELY SCATTERED MODERATE WITHIN 60 NM OF LINE 8N16W 8N19.5W AND FROM 3.5N-5.5N BETWEEN 9W-15W. CLUSTERS OF MODERATE CONVECTION ARE WITHIN 90 NM OF 5N20W AND WITHIN 45 NM OF THE ITCZ W OF 44W. ISOLATED MODERATE S OF 3N BETWEEN 30W-42W. ...DISCUSSION... GULF OF MEXICO... BIGGEST CHANGE TO THE WEATHER SINCE YESTERDAY IS A SLUG OF DEEP-LAYERED MOISTURE THAT HAS ENTERED THE AREA S OF 25N E OF 94.5W. ISOLATED SHOWERS ARE BENEATH THE CLOUD CANOPY WITH TSTMS CLOSE TO ENTERING THE STRAITS OF FLORIDA. THIS MOISTURE... ASSOCIATED WITH THE REMNANTS OF LAST WEEK'S COLD FRONT NOW A TROUGH...IS BEING PULLED INTO THE REGION DUE TO SLY WINDS TO THE E OF A MID/UPPER LOW THAT HAS FORMED NEAR NE MEXICO AROUND 24N97W. THIS MOISTURE SHOULD MAKE ITS WAY INTO THE CENTRAL GULF REGION MOSTLY E OF 92W S OF 28N FOR THE EARLY PART OF THE WEEK.. PROBABLY BRINGING MUCH NEEDED RAIN TO S THEN CENTRAL FLORIDA. WEAK HIGH PRESSURE IS JUST OFFSHORE OF NW FLORIDA NEAR 28N86.5W AND SHOULD REMAIN NEARLY STATIONARY WITH GENERALLY LIGHT WINDS. A LONE CLUSTER OF TSTMS IS NEAR 27.5N95W IN THE NW GULF NEAR THE UPPER LOW. CARIBBEAN SEA AND ATLANTIC OCEAN W OF 60W... BROAD UPPER TROUGHING IS LIMITED TO THE FAR NORTHERN PART OF THE AREA N OF 26N AND IS BEING TAKEN OVER BY A BUILDING HIGH CENTERED NEAR HAITI RIDGING WSW TO THE GULF OF HONDURAS AND EASTWARD ALONG 20N. THIS HIGH IS MUCH FARTHER N THAN AVERAGE AND LOOKS MORE TYPICAL FOR MID-SUMMER THAN LATE SPRING CONDITIONS. AT THE N EDGE OF THE HIGH.. TROUGH IS POSITIONED ALONG 31N60W 26N70W TO NEAR ANDROS ISLANDS SW INTO THE CARIBBEAN TO NEAR 19N85W. ISOLATED SHOWERS AND BROKEN CLOUDINESS ARE WITHIN 180 NM OF THE TROUGH E OF THE BAHAMAS. MORE WIDESPREAD SHOWERS AND SOME TSTMS ARE WITHIN 180 NM OF THE TROUGH W OF THE BAHAMAS WITH PLENTIFUL UPPER CLOUDINESS FROM DYING TSTMS IN THE NW CARIBBEAN. SOME TSTMS COULD BREAK OUT OVER YUCATAN TODAY IF ENOUGH SOLAR HEATING DESTABILIZES THE MOIST ATMOSPHERE IN PLACE IN ADDITION TO W CUBA. NW OF THE TROUGH... NEARLY CLOUD-FREE SKIES ARE IN PLACE SAVE SOME PASSING CIRRUS CLOUDS. IN THE CENTRAL AND E CARIBBEAN...MODERATE/STRONG SUBSIDENCE BENEATH THE UPPER RIDGE IS KEEPING ANY SIGNIFICANT CONVECTION CONFINED TO THE FAR SW CARIBBEAN WITHIN 60 NM OF CENTRAL AMERICA S OF 11N. A WEAK LOW LEVEL TROUGH IS ALONG ABOUT 70W WITH A FEW SHOWERS N OF 14N BETWEEN 67W-72W AND A FEW SHOWERS ARE ALSO PASSING THRU THE LEEWARD ISLANDS THIS AFTERNOON. SOME ASH IS ALSO IN THE AREA BUT IT IS GETTING HARDER TO SEE ON SATELLITE. VISIBLE IMAGES SHOW THAT ASH IS STILL BEING EMITTED FROM THE MONTSERRAT VOLCANO BUT IT IS MUCH REDUCED FROM YESTERDAY. A LITTLE STRONGER THAN AVERAGE TRADES CONTINUE ACROSS THE CENTRAL/E CARIBBEAN WITH NO BIG CHANGES FOR THE FIRST PART OF THE WEEK. THE REMAINDER OF ATLANTIC OCEAN... A SHARP UPPER LEVEL TROUGH IS OVER THE CNTRL ATLC WITH THE AXIS EXTENDING THRU 30N46W THROUGH AN UPPER LOW NEAR 21N49W AND INTO THE DEEP TROPICS NEAR 10N54W. THE UPPER LOW IS HELPING TO TRANSPORT UPPER MOISTURE FROM THE DEEP TROPICS NEWARD WITHIN 180 NM TO THE RIGHT OF A LINE ALONG 10N51W 20N45W 28N45W. AN UPPER HIGH IS NEAR 20N32W WITH MID/UPPER LEVEL RIDGING COVERING THE AREA S OF 17N AND E OF 37W AND POKING NORTHWARD TO 31N38W. DIFFLUENCE S OF THE RIDGE IS ENHANCING ITCZ CONVECTION. NW FLOW IS IN THE NE PART OF THE ATLC AS A RESULT OF AN UPPER TROUGH OVER EXTREME NW AFRICA. THAT UPPER TROUGH IS ENHANCING TSTMS OVER PORTIONS OF MAURITANIA AND MALI THAT RARELY RECEIVE RAIN ESPECIALLY THIS EARLY IN THE RAINY SEASON. AT THE SFC...A 1026 MB HIGH CENTERED NEAR 31N38W COVERS THE ENTIRE REGION SUPPLYING FAIR WEATHER ACROSS A GOOD PORTION OF THE ATLANTIC OCEAN. TRADE WINDS ARE RATHER STRONG ACROSS THE AREA AND WILL LIKELY REMAIN THAT WAY FOR THE NEXT FEW DAYS. $$ BLAKE