| apparently, so does HPC, or at least they did a day ago? http://www.hpc.ncep.noaa.gov/discussions/fxca20.html CARIBBEAN FORECAST DISCUSSION TROPICAL DISCUSSION - INTERNATIONAL DESKS NWS HYDROMETEOROLOGICAL PREDICTION CENTER CAMP SPRINGS MD 229 PM EDT FRI JUN 18 2010 DISCUSSION FROM JUN 18/0000 UTC. AT MID/UPPER LEVELS... A RIDGE EXTENDS FROM WESTERN/NORTHERN MEXICO INTO THE SOUTHEASTERN USA. THE MODELS SHOW THIS AXIS BUILDING TO THE EAST AND NORTHEAST ACROSS THE SOUTHERN USA THROUGH 36-48 HRS... THEN FORECAST IT TO DRIFT BACK TO THE WEST TO NORTHWESTERN MEXICO/TEXAS BY 72-84 HRS. A TUTT LOW INITIALIZED OVER WESTERN CUBA WILL SPLIT INTO TWO PARTS. ONE IS FORECAST TO TRACK TO THE SOUTHWEST TO THE CAMPECHE SOUND/YUCATAN PENINSULA BY 24-36 HRS AND CONTINUE WEST INTO CENTRAL MEXICO/GUANAJUATO BY 72/84 HRS WHERE IT WILL WEAKEN. THE EASTERN PORTION OF THE TUTT WILL MOVE NORTHEAST TO THE CENTRAL BAHAMAS BY 36-48 HRS. THIS TUTT LOW WILL THEN MOVE LITTLE BUT GRADUALLY WEAKEN THROUGH THE CYCLE. OVER THE BAHAMAS EXPECT SCATTERED CONVECTION EACH DAY WITH 05-15MM/DAY AND MAXIMA OF 15-20MM/DAY. AT LOW LEVELS... HIGH PRESSURE OVER THE SOUTHEASTERN USA MAINTAINS A BRISK EASTERLY FLOW ACROSS THE YUCATAN TO THE EASTERN STATES OF MEXICO... WITH FLOW CONVERGING ALONG THE COASTAL PLAINS/SIERRA MADRE. AS THIS FLOW GRADUALLY WEAKENS... CONVECTION ACROSS VERACRUZ-CENTRAL AND SOUTHERN STATES OF MEXICO WILL ALSO DIMINISH. EXPECT RAINFALL AMOUNTS OF 15-30MM/DAY AND MAXIMA OF 20-50MM/DAY ON DAY 01 DIMINISHING TO 10-20MM/DAY AND MAXIMA OF 20-30MM/DAY ON DAY 03. AT 250 HPA... THE SUBEQUATORIAL RIDGE CONTINUES TO STRENGTHEN ACROSS THE TROPICAL ATLANTIC INTO EASTERN CARIBBEAN. THE RIDGE IS BUILDING WEST ALONG 13N/15N... WITH A CLOSED HIGH TO DEVELOP/BUILD ACROSS THE ABC ISLANDS AND NORTHWARD INTO THE CARIBBEAN. THROUGH 36-48 HRS THE RIDGE WILL EXPAND TO THE WEST ACROSS CENTRAL AMERICA. A TUTT/TUTT LOW NORTH OF PUERTO RICO SEEMS TO HAVE STALLED WHILE THE SUBEQUATORIAL RIDGE CONTINUES TO BUILD WEST. AS THE RIDGE PRESSES AGAINST THE TUTT IT IS CREATING A HIGH SHEAR ENVIRONMENT ACROSS PUERTO RICO-VIRGIN/LEEWARD ISLANDS. AS A RESULT...A PERTURBATION IN THE LOW/MID LEVEL EASTERLIES ENTERING THE ISLAND CHAIN IS ENCOUNTERING A VERY HOSTILE ENVIRONMENT...WHICH IS FORCING SOME OF THE ENERGY/MOISTURE TO SHRED NORTHWARD WHILE THE PERTURBATION PUSHES EAST ACROSS THE ISLANDS. THE MODELS CONTINUE TO FORECAST THE TUTT NORTH OF PUERTO RICO TO RECEDE AS THE SUBEQUATORIAL RIDGE PATTERN ALOFT INTENSIFIES DURING THE NEXT 24-48 HRS. THIS WILL THEN BECOME THE DOMINANT SYNOPTIC SCALE FEATURE ACROSS THE CARIBBEAN BASIN. THIS...IN-TURN...WILL FAVOR A DEEP UNSTABLE LAYER...WHICH WILL ALLOW MOISTURE TO POOL ACROSS THE EASTERN CARIBBEAN ISLANDS AS THE AFOREMENTIONED WAVE PROPAGATES ACROSS THE AREA. THIS IS TO THEN PERSIST INTO THE EARLY PART OF NEXT WEEK. MODELS ARE FORECASTING A DEEP MOIST LAYER ASSOCIATED WITH THE WAVE OVER THE EASTERN CARIBBEAN EARLY IN THE PERIOD TO RAPIDLY EXPAND ACROSS THE CENTRAL TO WESTERN CARIBBEAN AS THE CYCLE PROGRESSES. THIS MOISTURE WILL REACH PUERTO RICO AND THE LEEWARD/WINDWARD ISLANDS ON DAY 01... HISPANIOLA BY 48 HRS... AND EASTERN CUBA BY 72/84 HRS. AS THE TUTT MEANDERS OVER THE WESTERN CARIBBEAN... IT WILL INTERACT WITH THE ITCZ AS THE LATTER MEANDERS NORTH OF PANAMA/COSTA RICA INTO THE SOUTHERN CARIBBEAN. EARLY IN THE CYCLE THIS WILL FAVOR RAINFALL AMOUNTS OF 15-20MM/DAY AND MAXIMA OF 25-60MM/DAY ACROSS SOUTHERN NICARAGUA/NORTHERN COSTA RICA. AS THE LOW PULLS ACROSS CUBA...IT WILL ENHANCE LATE AFTERNOON CONVECTION TO SUSTAIN RAINFALL AMOUNTS OF 05-10MM/DAY AND MAXIMA OF 15-25MM/DAY. SOME ENHANCEMENT IS ALSO POSSIBLE ACROSS JAMAICA...WHERE WE EXPECT ACCUMULATION OF 05-10MM/DAY AND MAXIMA OF 15-25MM. OVER THE NORTHWEST AND CENTRAL BAHAMAS EXPECT ACCUMULATION OF 05-10MM/DAY AND MAXIMA OF 15-25MM. PERTURBATIONS IN THE EASTERLIES...INITIALIZED AT 12UTC. INITIAL 24 36 48 60 72 84 52W 56W 59W 62W 64W 66W 69W 63W 66W 69W 72W 75W 78W 81W 74W 76W 79W 81W 83W 86W 89W 84W 86W 88W 90W 92W 94W 96W 96W 98W 99W 100W 102W 103W 104W A PERTURBATION IN THE EASTERLIES IS INITIALIZED ALONG 52W AND SOUTH OF 11N. OVER SURINAME-GUYANA TO EASTERN VENEZUELA-TRINIDAD/TOBAGO IT WILL FAVOR ACCUMULATION OF 10-15MM/DAY AND MAXIMA OF 25-45MM/DAY. OVER EASTERN AND CENTRAL VENEZUELA IT WILL FAVOR ACCUMULATION OF 10-15MM/DAY AND MAXIMA OF 20-30MM/DAY. A PERTURBATION IN THE EASTERLIES LIES ALONG 63W AND SOUTH OF 22N. UNDER THE INFLUENCE OF THE BUILDING SUBEQUATORIAL RIDGE PATTERN AND THE TUTT NORTH OF THE ISLANDS THE WAVE AXIS CONTINUES TO AMPLIFY NORTH. THIS WILL FORCE ADDITIONAL MOISTURE TO SURGE ACROSS THE EASTERN CARIBBEAN EARLY IN THE CYCLE ACROSS PUERTO RICO AND HISPANIOLA. EXPECT RAINFALL AMOUNTS ACROSS PUERTO RICO AND HISPANIOLA OF 15-25MM/DAY AND MAXIMA OF 35-70MM. FURTHERMORE...THE MODELS HAVE BEEN SHOWING MOST ACTIVE CONVECTION DEVELOPING POST-WAVE PASSAGE EARLY IN THE PERIOD. UNDER THE INFLUENCE OF THE TUTT TO THE NORTH SOME OF THE MODELS PULL THE MOISTURE AND MOST ACTIVE CONVECTION TO THE NORTH... WHILE OTHERS TAKE IT ACROSS THE VIRGIN ISLANDS TO PUERTO RICO. THE SATELLITE IMAGERY SUGGESTS MOISTURE TO BE PULLING NORTH OF 18N/20N DRAWN BY THE TUTT AXIS AS IT RETROGRESSES ACROSS THE BASIN. ACROSS THE LEEWARD ISLANDS... WE EXPECT ACCUMULATION OF 10-15MM/DAY AND MAXIMA OF 25-45MM DIMINISHING TO MAXIMA OF 15-20MM ON DAY 03. A TROPICAL WAVE ALONG 74W AND SOUTH OF 16N IS MOVING ACROSS EASTERN COLOMBIA. OVER SANTANDERES-SIERRA NEVADA DE SANTA MARTA IN NORTHERN COLOMBIA-EJE CAFETERO/GULF OF URABA REGION TO THE DARIEN IN EASTERN PANAMA IT WILL FAVOR ACCUMULATION OF 10-15MM/DAY AND MAXIMA OF 20-30MM/DAY. OVER PANAMA/COSTA RICA EXPECT 10-15MM/DAY WITH MAXIMA OF 20-35MM/DAY. A PERTURBATION IN THE EASTERLIES ALONG 84W AND SOUTH OF 15N IS INTERACTING WITH THE ITCZ ACROSS HONDURAS... NICARAGUA... AND EL SALVADOR WHERE IT WILL SUSTAIN ACCUMULATION OF 15-20MM/DAY AND MAXIMA OF 30-60MM/DAY WHILE OVER GUATEMALA... CHIAPAS... AND EASTERN OAXACA IN SOUTHERN MEXICO IT WILL FAVOR ACCUMULATION OF 10-20MM/DAY AND MAXIMA OF 20-35MM/DAY. A TROPICAL WAVE ALONG 96W AND SOUTH OF 17N IS INTERACTING WITH THE EASTERN PACIFIC ITCZ... TO SUSTAIN RAINFALL AMOUNTS OF 10-15MM/DAY AND MAXIMA OF 20-50MM/DAY OVER SOUTHERN MEXICO FROM JALISCO EAST TO OAXACA. MAXIMA RAINFALL WILL DIMINISH TO 20-30MM/DAY BY DAY 03. NARANJO...IMN (COSTA RICA) SHAKEER...TTMS (TRINIDAD AND TOBAGO) DAVISON/DANAHER...NCEP (USA) Last Updated: 229 PM EDT FRI JUN 18 2010 |