000 AXNT20 KNHC 281804 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 205 PM EDT SAT SEP 28 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1715 UTC. ...SPECIAL FEATURES... A 1011 MB ATLANTIC OCEAN LOW PRESSURE PRESSURE CENTER IS NEAR 23N51W. THIS POSITION IS ABOUT 750 NM TO THE EAST-NORTHEAST OF THE NORTHEASTERN CORNER OF THE CARIBBEAN SEA. IT IS POSSIBLE THAT A TROPICAL DEPRESSION MAY FORM THIS SYSTEM DURING THE NEXT DAY OR TWO AS THE LOW MOVES NORTHWARD AND THEN NORTHEASTWARD 9 TO 13 KNOTS. THIS SYSTEM HAS A HIGH CHANCE OF BECOMING A TROPICAL CYCLONE DURING THE NEXT 48 HOURS. ENVIRONMENTAL CONDITIONS APPEAR TO BE MARGINALLY CONDUCIVE FOR DEVELOPMENT AFTER 48 HOURS. THE SYSTEM HAS A HIGH CHANCE 70 PERCENT OF BECOMING A TROPICAL CYCLONE DURING THE NEXT 5 DAYS. ADDITIONAL INFORMATION ON THIS SYSTEM IS FOUND IN HIGH SEAS FORECASTS THAT ARE ISSUED BY THE NATIONAL WEATHER SERVICE. CONVECTIVE PRECIPITATION...NUMEROUS STRONG FROM 24N TO 26N BETWEEN 48W AND 51W. ...TROPICAL WAVES... AN ATLANTIC OCEAN TROPICAL WAVE IS ALONG 23W TO THE SOUTH OF 17N MOVING WESTWARD 15 KNOTS. CONVECTIVE PRECIPITATION...NUMEROUS STRONG FROM 13N TO 16N BETWEEN 21W AND 22W. SCATTERED MODERATE TO ISOLATED STRONG ELSEWHERE FROM 7N TO 15N BETWEEN 21W AND 30W. AN ATLANTIC OCEAN TROPICAL WAVE IS ALONG 56W TO THE SOUTH OF 18N...MOVING WESTWARD 15 KNOTS. NO SIGNIFICANT DEEP CONVECTIVE PRECIPITATION IS APPARENT. A CARIBBEAN SEA TROPICAL WAVE IS ALONG 63W/64W TO THE SOUTH OF 17N MOVING WESTWARD 10 TO 15 KNOTS. IT IS MOVING THROUGH THE AREA OF A MIDDLE LEVEL TO UPPER LEVEL TROUGH THAT EXTENDS FROM AN ATLANTIC OCEAN 27N56W CYCLONIC CIRCULATION CENTER...TO 22N57W 17N60W TO 14N62W AND 10N63W IN NORTHEASTERN VENEZUELA. THE TROPICAL WAVE ALSO IS SURROUNDED BY COMPARATIVELY DRIER AIR IN SUBSIDENCE IN WATER VAPOR IMAGERY. RAINSHOWERS ARE POSSIBLE IN THE CARIBBEAN SEA AND IN THE ATLANTIC OCEAN FROM 10N TO 15N BETWEEN 58W AND 65W...MOST LIKELY AS A RESULT OF THE MIDDLE LEVEL TO UPPER LEVEL TROUGH. ...THE ITCZ/THE MONSOON TROUGH... THE MONSOON TROUGH PASSES THROUGH THE COASTAL AREAS OF GAMBIA TO 10N24W AND 9N29W. THE ITCZ CONTINUES FROM 9N29W 7N35W 4N39W AND 3N43W. CONVECTIVE PRECIPITATION...NUMEROUS STRONG FROM 4N TO 6N BETWEEN 32W AND 33W...FROM 7N TO 9N BETWEEN 45W AND 47W...FROM 6N TO 7N BETWEEN 49W AND 51W...AND FROM 6N TO 7N BETWEEN 53W AND 55W. WIDELY SCATTERED MODERATE TO ISOLATED STRONG ELSEWHERE FROM 3N TO 10N BETWEEN 30W AND 56W. ...DISCUSSION... FROM THE CENTRAL ATLANTIC OCEAN...INTO THE WESTERN ATLANTIC OCEAN...ACROSS THE BAHAMAS AND INTO THE GULF OF MEXICO... A MIDDLE LEVEL TO UPPER LEVEL TROUGH EXTENDS FROM A 34N74W CYCLONIC CIRCULATION CENTER TO 27N76W TO CUBA NEAR 23N80W TO 19N80W AND THE COAST OF HONDURAS NEAR 16N85W. A COLD FRONT PASSES THROUGH 32N51W TO 30N56W. THE FRONT BECOMES STATIONARY FROM 30N56W TO 29N64W...AND TO A 1008 MB LOW PRESSURE CENTER THAT IS NEAR 29N70W. A COLD FRONT EXTENDS FROM THE 1008 MB LOW CENTER TO 26N70W...TO 23N74W IN THE BAHAMAS...TO 23N80W ALONG THE COAST OF CUBA. THE FRONT BECOMES STATIONARY AGAIN FROM 23N80W TO 23N89W. A SHEAR AXIS/REMNANT CLOUD LINE EXTENDS FROM 23N89W TO 25N93W AND TO THE CENTRAL TEXAS GULF COAST NEAR 29N96W. CONVECTIVE PRECIPITATION...SCATTERED MODERATE TO ISOLATED STRONG IN THE ATLANTIC OCEAN IN THE AREA THAT IS BOUNDED BY THE POINTS FROM 22N77W TO 24N66W TO 27N57W 30N59W 33N63W 22N77W. ISOLATED MODERATE ELSEWHERE IN THE ATLANTIC OCEAN TO THE NORTH OF 20N TO THE WEST OF 60W. RAINSHOWERS ARE POSSIBLE IN THE GULF OF MEXICO WITHIN 30 TO 60 NM ON EITHER SIDE OF 25N82W 27N86W 30N87W...AND WITHIN 30 NM TO 60 NM ON EITHER SIDE OF THE GULF OF MEXICO STATIONARY FRONT/SHEAR AXIS. ONE INCH OF RAIN WAS RECORDED AT VERACRUZ IN MEXICO DURING THE LAST 24 HOURS ENDING AT 28/1200 UTC...ACCORDING TO THE MIATPTPAN BULLETIN. FAIR SKIES COVER THE REST OF THE GULF OF MEXICO. FROM CUBA INTO THE NORTHWESTERN CORNER OF THE CARIBBEAN SEA INCLUDING HISPANIOLA AND A 63W/64W TROPICAL WAVE... UPPER LEVEL SOUTHWESTERLY WIND FLOW IS MOVING ACROSS HISPANIOLA. COMPARATIVELY DRIER AIR IN SUBSIDENCE IN WATER VAPOR IMAGERY COVERS THE AREA. NO SIGNIFICANT DEEP CONVECTIVE PRECIPITATION IS APPARENT. A MIDDLE LEVEL TO UPPER LEVEL SHORTWAVE TROUGH EXTENDS FROM CUBA NEAR 23N80W TO 16N85W ALONG THE COAST OF HONDURAS. THE CYCLONIC WIND FLOW COVERS THE CARIBBEAN SEA FROM 16N TO CUBA BETWEEN THE WINDWARD PASSAGE AND THE YUCATAN CHANNEL. A CARIBBEAN SEA TROPICAL WAVE IS ALONG 63W/64W TO THE SOUTH OF 17N MOVING WESTWARD 10 TO 15 KNOTS. THE TROPICAL WAVE IS MOVING THROUGH THE AREA OF A MIDDLE LEVEL TO UPPER LEVEL 27N56W-TO- 10N63W TROUGH. THE TROPICAL WAVE ALSO IS SURROUNDED BY COMPARATIVELY DRIER AIR IN SUBSIDENCE IN WATER VAPOR IMAGERY. THE GFS FORECAST FOR 700 MB SHOWS THAT AN EAST-TO-WEST ORIENTED RIDGE WILL COVER THE AREA. THE 500 MB GFS MODEL SHOWS THAT HISPANIOLA WILL BE ON THE EASTERN SIDE OF A TROUGH FOR THE ENTIRE 48 HOURS OF THE FORECAST PERIOD. THE GFS FORECAST FOR 250 MB SHOWS THAT A TROUGH WILL CUT ACROSS THE AREA FOR MUCH OF THE FIRST 24 HOURS. THE TROUGH WILL MOVE NORTHEASTWARD AND OUT OF THE AREA. THE TROUGH WILL BE REPLACED BY A NORTHEAST-TO- SOUTHWEST ORIENTED RIDGE. HISPANIOLA WILL BE ON THE NORTHWESTERN SIDE OF THE RIDGE. ANTICYCLONIC WIND FLOW WILL COVER THE AREA FOR THE NEXT 48 HOURS. THE REST OF THE CARIBBEAN SEA... AN AREA OF DISTURBED WEATHER HAS FORMED IN THE SOUTHWESTERN CARIBBEAN SEA. SLOW DEVELOPMENT OF THIS SYSTEM IS POSSIBLE DURING THE NEXT COUPLE OF DAYS AS IT MOVES NORTHWESTWARD SLOWLY. THIS SYSTEM HAS A LOW CHANCE OF BECOMING A TROPICAL CYCLONE DURING THE NEXT 48 HOURS. CONDITIONS APPEAR TO BE CONDUCIVE FOR SOME DEVELOPMENT AFTER 48 HOURS...AS THE SYSTEM MOVES TOWARD THE NORTHWESTERN CARIBBEAN SEA AND SOUTHEASTERN GULF OF MEXICO. THIS SYSTEM HAS A MEDIUM CHANCE OF BECOMING A TROPICAL CYCLONE DURING THE NEXT 5 DAYS. AN UPPER LEVEL RIDGE EXTENDS FROM SOUTHWESTERN HAITI... SOUTHWARD...BEYOND THE GULF OF URABA OF COLOMBIA. BROAD SURFACE LOW PRESSURE...INCLUDING AROUND THE MONSOON TROUGH... COVERS THE CARIBBEAN SEA TO THE SOUTH OF 16N TO THE WEST OF 69W. NUMEROUS STRONG CONVECTIVE PRECIPITATION COVERS THE CARIBBEAN SEA TO THE SOUTH OF 16N BETWEEN 72W AND 78W. WIDELY SCATTERED MODERATE TO ISOLATED STRONG CONVECTIVE PRECIPITATION COVERS THE REST OF THE CARIBBEAN SEA TO THE SOUTH OF 16N TO THE WEST OF 78W. THE MONSOON TROUGH EXTENDS FROM NORTHERN COLOMBIA NEAR 9N74W TO 9N79W IN PANAMA...BEYOND TO 10N86W IN COSTA RICA...INTO THE EASTERN PACIFIC OCEAN. THE REST OF THE ATLANTIC OCEAN... A MIDDLE LEVEL TO UPPER LEVEL TROUGH IS ALONG 24N26W...TO A COMPARATIVELY WEAK 17N34W CYCLONIC CIRCULATION CENTER...TO 13N37W. NO SIGNIFICANT DEEP CONVECTIVE PRECIPITATION IS APPARENT. A 1023 MB HIGH PRESSURE CENTER IS NEAR 26N39W. SURFACE ANTICYCLONIC WIND FLOW COVERS THE ATLANTIC OCEAN TO THE NORTH OF 18N BETWEEN AFRICA AND 44W. PLEASE READ THE HIGH SEAS FORECAST...MIAHSFAT2...FOR MORE DETAILS ABOUT THE STATIONARY FRONT FROM 31N55W TO A 1008 MB LOW PRESSURE CENTER NEAR 29N70W...NORTHEAST WINDS 20 TO 25 KNOTS AND 8 FOOT SEA HEIGHTS WITHIN 90 NM OF THE LOW CENTER IN THE NORTHERN QUADRANT. EXPECT SOUTHWESTERLY WINDS 20 TO 25 KNOTS AND 9 TO 13 FOOT SEA HEIGHTS TO THE NORTH OF 29N BETWEEN 46W AND 52W. ALSO EXPECT WINDS 20 KNOTS OR LESS AND SEA HEIGHTS TO 10 FEET ELSEWHERE TO THE NORTH OF 28N BETWEEN 41W AND 55W. A SECOND FEATURE IS A 1011 MB LOW PRESSURE CENTER THAT IS NEAR 23N50.5W. EXPECT WINDS 20 TO 30 KNOT AND SEA HEIGHTS TO 9 FEET WITHIN 90 NM OF THE LOW CENTER IN THE EAST SEMICIRCLE. A THIRD AREA CONSISTS OF WINDS 20 KNOTS OR LESS AND SEA HEIGHTS TO 9 FEET TO THE SOUTH OF 16N TO THE EAST OF 45W. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ MT