000 AXNT20 KNHC 181144 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 805 AM EDT THU JUL 18 2013 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...WEATHER OBSERVATIONS...RADAR...AND METEOROLOGICAL ANALYSIS. BASED ON 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1045 UTC. ...TROPICAL WAVES... AN ATLANTIC OCEAN TROPICAL WAVE IS ALONG 22N29W 16N32W 10N33W...MOVING WESTWARD 15 TO 20 KNOTS. CONVECTIVE PRECIPITATION...SCATTERED MODERATE TO ISOLATED STRONG IN THE ITCZ FROM 8N TO 10N BETWEEN 27W AND 33W. A CARIBBEAN SEA TROPICAL WAVE IS ALONG 65W/66W TO THE SOUTH OF 22N...MOVING WESTWARD 20 TO 25 KNOTS. CONVECTIVE PRECIPITATION...SCATTERED MODERATE TO ISOLATED STRONG FROM 14N TO 22N BETWEEN 60W AND 71W. THE PRECIPITATION THAT IS JUST TO THE SOUTH OF THE DOMINICAN REPUBLIC IS RACING WESTWARD...MOVING COMPARATIVELY FASTER THAN THE REST OF THE PRECIPITATION. A CARIBBEAN SEA TROPICAL WAVE IS ALONG 78W/79W TO THE SOUTH OF 18N...MOVING WESTWARD 20 KNOTS. BROAD UPPER LEVEL ANTICYCLONIC WIND FLOW IS MOVING ACROSS THE WAVE...IN THE SOUTHWESTERN CORNER OF THE CARIBBEAN SEA. NO SIGNIFICANT DEEP CONVECTIVE PRECIPITATION IS APPARENT. ...ITCZ/MONSOON TROUGH... THE MONSOON TROUGH PASSES THROUGH COASTAL MAURITANIA NEAR 19N16W TO 15N23W 11N27W. THE ITCZ STARTS NEAR 11N27W TO 9N30W 7N40W 6N40W AND 4N50W. CONVECTIVE PRECIPITATION...SCATTERED TO NUMEROUS STRONG FROM 5N TO 9N BETWEEN 51W AND 57W FROM THE COAST OF BRAZIL TO THE COASTAL WATERS OF GUYANA. SCATTERED MODERATE TO ISOLATED STRONG FROM 6N TO 11N TO THE EAST OF 20W... AND WITHIN 90 NM ON EITHER SIDE OF 11N23W 9N30W 7N40W 6N48W. ...DISCUSSION... FROM THE ATLANTIC OCEAN...INTO THE CARIBBEAN SEA...TO THE NORTH OF 15N BETWEEN 59W AND 71W... A MIDDLE LEVEL TO UPPER LEVEL CYCLONIC ENVELOPE COVERS THE AREA. MULTIPLE CYCLONIC CIRCULATION CENTERS ARE PRESENT IN THE AREA...IN THE ATLANTIC OCEAN. ONE IS NEAR 29N63W. A SECOND CENTER IS NEAR 28N71W. AN ATLANTIC OCEAN SURFACE TROUGH IS ALONG 71W/72W FROM 26N TO 31N. CONVECTIVE PRECIPITATION...ISOLATED MODERATE BETWEEN 55W AND 72W TO THE NORTH OF 20N. MIDDLE LEVEL TO UPPER LEVEL ANTICYCLONIC WIND FLOW FROM A 20N74W 30N80W RIDGE COVERS THE ATLANTIC OCEAN THAT IS BETWEEN 71W AND 80W. WARMING CLOUD TOP TEMPERATURES AND WEAKENING CONVECTIVE PRECIPITATION ARE UNDER THE RIDGE. GULF OF MEXICO... ONE MIDDLE LEVEL TO UPPER LEVEL CYCLONIC CIRCULATION CENTER IS NEAR 28N87W OFF THE COAST OF FLORIDA. SURFACE TROUGHS ARE ALONG 26N87W 28N84W AND 28N87W 31N84W. CONVECTIVE PRECIPITATION... SCATTERED MODERATE TO ISOLATED STRONG TO THE SOUTH OF 28N TO THE EAST OF 87W IN THE SOUTHEASTERN CORNER OF THE GULF OF MEXICO. SCATTERED MODERATE TO THE WEST OF 90W ALSO. A SECOND CYCLONIC CIRCULATION CENTER APPEARS TO BE WEAKENING AS ITS CYCLONIC WIND FLOW COVERS THE YUCATAN PENINSULA. BROAD MULTILAYERED NORTHERLY-TO-NORTHWESTERLY WIND FLOW COVERS THE REST OF THE GULF OF MEXICO. A SURFACE TROUGH IS ALONG THE WESTERN SIDE OF THE YUCATAN PENINSULA OF MEXICO. A MIDDLE LEVEL CLOUD CEILING IS OBSERVED AT BROWNSVILLE TEXAS. HIGH LEVEL CLOUD CEILINGS ARE REPORTED IN THE NEW ORLEANS LOUISIANA METROPOLITAN AREA. A HIGH CLOUD CEILING IS IN VALPARAISO FLORIDA. A LOW CLOUD CEILING COVERS TALLAHASSEE...AND MARATHON KEY. MIDDLE LEVEL AND HIGH LEVEL CLOUD CEILINGS ARE IN THE TAMPA METROPOLITAN AREA...AND IN THE FLORIDA KEYS IN MARATHON AND AT THE KEY WEST NAVAL AIR STATION. FAIR SKIES/CLEAR SKIES AT OR LOWER THAN 12000 FEET ARE BEING REPORTED ELSEWHERE. FOR THE OFFSHORE OIL PLATFORM SITES THAT ARE TO THE NORTH OF 27N TO THE WEST OF 88W... A LOW CLOUD CEILING AND A MIDDLE LEVEL CLOUD CEILING ARE REPORTED AT THE ICAO STATION KMZG OFF THE TEXAS COAST. A LOW CLOUD CEILINGS IS OBSERVED AT THE ICAO STATION KBBF. FAIR SKIES/CLEAR SKIES AT OR LOWER THAN 12000 FEET ARE BEING REPORTED ELSEWHERE. CARIBBEAN SEA... UPPER LEVEL ANTICYCLONIC WIND FLOW COVERS THE AREA THAT IS TO THE SOUTH OF THE LINE THAT RUNS FROM THE YUCATAN PENINSULA OF MEXICO...TO 15N75W...AND TO THE PENINSULA DE LA GUAJIRA OF NORTHERN COLOMBIA. A MIDDLE LEVEL TO UPPER LEVEL INVERTED TROUGH IS ALONG 19N63W 15N61W 9N59W. WIDELY SCATTERED MODERATE TO ISOLATED STRONG CONVECTIVE PRECIPITATION IS IN THE NORTHWESTERN CORNER OF THE AREA...IN AN AREA OF DIFFLUENT WIND FLOW...TO THE NORTH OF 18N TO THE WEST OF 80W. A CARIBBEAN SEA TROPICAL WAVE IS ALONG 65W/66W TO THE SOUTH OF 22N...MOVING WESTWARD 20 TO 25 KNOTS. CONVECTIVE PRECIPITATION...SCATTERED MODERATE TO ISOLATED STRONG FROM 14N TO 22N BETWEEN 60W AND 71W. THE PRECIPITATION THAT IS JUST TO THE SOUTH OF THE DOMINICAN REPUBLIC IS RACING WESTWARD...MOVING COMPARATIVELY FASTER THAN THE REST OF THE PRECIPITATION. THE WAVE SHOULD BE AFFECTING HISPANIOLA TODAY. THE MONSOON TROUGH IS ALONG 9N BETWEEN 73W IN COLOMBIA...AND BEYOND 83W IN SOUTHERN COSTA RICA. CONVECTIVE PRECIPITATION... NUMEROUS STRONG IN THE EASTERN PACIFIC OCEAN COASTAL WATERS OF COLOMBIA AND PANAMA FROM 4N TO 9N TO THE EAST OF 80W. SCATTERED STRONG IN THE SOUTHWESTERN CORNER OF THE CARIBBEAN SEA TO THE SOUTH OF 12N84W 10N77W. SCATTERED MODERATE TO STRONG ALONG THE COAST OF NICARAGUA FROM 13N TO 14N BETWEEN 82W AND 84W. HISPANIOLA... A CARIBBEAN SEA TROPICAL WAVE IS ALONG 65W/66W TO THE SOUTH OF 22N...MOVING WESTWARD 20 TO 25 KNOTS. CONVECTIVE PRECIPITATION...SCATTERED MODERATE TO ISOLATED STRONG FROM 14N TO 22N BETWEEN 60W AND 71W. THE PRECIPITATION THAT IS JUST TO THE SOUTH OF THE DOMINICAN REPUBLIC IS RACING WESTWARD...MOVING COMPARATIVELY FASTER THAN THE REST OF THE PRECIPITATION. THE WAVE SHOULD BE AFFECTING HISPANIOLA TODAY. THE GFS FORECAST FOR 700 MB SHOWS EASTERLY WIND FLOW ACROSS THE AREA FOR THE FIRST 30 HOURS OR SO... FOLLOWED BY SOUTHEASTERLY WIND FLOW ACROSS THE AREA. THE GFS FORECAST FOR 500 MB STARTS WITH HISPANIOLA IN A RIDGE FOR MOST OF THE FIRST 24 HOURS... FOLLOWED BY AN INVERTED TROUGH MOVING WESTWARD ACROSS THE AREA. THE 250 MB GFS SHOWS THAT A TROUGH WILL START ON TOP OF THE AREA...FOLLOWED BY THE TRANSITION TO NORTHERLY WIND FLOW... FOLLOWED BY AN INVERTED TROUGH ACROSS THE AREA FOR THE REST OF THE 48 HOURS. THE REST OF THE ATLANTIC OCEAN... A SURFACE RIDGE EXTENDS FROM A 1024 MB HIGH PRESSURE CENTER THAT IS NEAR 32N23W TO 28N35W...TO A 1024 MB HIGH PRESSURE CENTER THAT IS NEAR 27N47W...TO 29N67W. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ MT