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AXNT20 KNHC 291755
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT SAT AUG 29 2015

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... T.S. ERICA DEGENERATES TO A TROUGH OF LOW PRESSURE. AT 1330 UTC...THE REMNANTS OF ERICA WERE ESTIMATED NEAR 21.5N 75.9W MOVING TOWARD THE W-NW NEAR 20-25 MPH. THIS GENERAL MOTION SHOULD CONTINUE FOR THE NEXT 24 HOURS OR SO...WITH THE REMNANTS OF ERICA EXPECTED TO MOVE NEAR THE COAST OF EASTERN AND CENTRAL CUBA THROUGH TONIGHT AND INTO THE SOUTHEASTERN GULF OF MEXICO ON SUN. THE MAIN IMPACT OF THIS SYSTEM WILL BE HEAVY RAINFALL ACROSS PARTS OF HISPANIOLA AND EASTERN AND CENTRAL CUBA THROUGH SUN RESULTING IN LIFE-THREATENING FLASH FLOODS AND DANGEROUS MUD SLIDES. RAINFALL AMOUNTS OF 3 TO 5 INCHES WITH LOCALLY HEAVIER AMOUNTS ARE POSSIBLE ACROSS SOUTHERN AND CENTRAL FLORIDA BEGINNING ON SUNDAY. CURRENTLY...SHOWERS AND TSTMS ASSOCIATED WITH THIS SYSTEM ARE AFFECTING PARTS OF EASTERN CUBA...THE TURKS AND CAICOS ISLANDS AND THE SE BAHAMAS. THE REMNANT LOW PRES IS FORECAST TO BE NEAR 24N81W BY SUN MORNING. THE LAST PUBLIC ADVISORY ON ERICA WAS ISSUED BY THE NHC AT 29/1330 UTC.

A TROPICAL WAVE IS MOVING JUST OFF THE COAST OF AFRICA WITH A 1008 MB LOW PRES ALONG THE WAVE AXIS NEAR 9.5N16W OR ABOUT 150 MILES WEST OF CONAKRY, GUINEA. SHOWERS AND TSTMS ASSOCIATED WITH THIS SYSTEM ARE GRADUALLY BECOMING BETTER ORGANIZED. SCATTERED MODERATE ISOLATED STRONG CONVECTION IS FROM 07N-13N BETWEEN 15W- 18W. ENVIRONMENTAL CONDITIONS ARE EXPECTED TO BE CONDUCIVE FOR DEVELOPMENT DURING THE NEXT FEW DAYS AND A TROPICAL DEPRESSION COULD FORM WHILE THE SYSTEM MOVES NW AND THEN W-NW TOWARD THE CAPE VERDE ISLANDS AT 10-15 MPH. THE LATEST NHC TROPICAL WEATHER OUTLOOK GIVES THIS LOW PRES A MEDIUM CHANCE OF DEVELOPING INTO A TROPICAL CYCLONE DURING THE NEXT 48 HOURS.


...TROPICAL WAVES...

A TROPICAL WAVE EXTENDS FROM 19N43W TO A 1013 MB LOW PRES LOCATED NEAR 12N45W TO 09N46W. THESE FEATURES ARE MOVING W AT ABOUT 15-20 KT OVER THE LAST 24 HOURS. VISIBLE SATELLITE IMAGERY INDICATED SOME INVERTED-V PATTERN IN THE CLOUD FIELD AS WELL AS A LARGE AREA OF SAHARAN DUST AROUND THE WAVE AXIS. SCATTERED MODERATE CONVECTION IS SEEN MAINLY W OF LOW CENTER FROM 9N-13N BETWEEN 45W-48W. THIS WAVE SHOWS UP VERY WELL IN THE LATEST GFS STREAMLINE AND 850 VORTICITY ANALYSIS AND WILL REACH THE TROPICAL N ATLC JUST E OF THE LESSER ANTILLES ON MON.

A TROPICAL WAVE IS ALONG 56W/57W FROM 10N-20N. SCATTERED SHOWERS ARE NEAR THE WAVE AXIS. THE WAVE WILL CONTINUE TO MOVE WESTWARD DURING THE NEXT FEW DAYS REACHING THE E CARIBBEAN SUN EVENING...AND MOVE THROUGH THE CENTRAL CARIBBEAN BY MON. THE WAVE IS DEPICTED IN THE LATEST GFS STREAMLINE AND 850 VORTICITY ANALYSIS...AND IT REMAINS EMBEDDED WITHIN AN AREA OF MOISTURE AS OBSERVED IN THE TPW ANIMATION.


...ITCZ/MONSOON TROUGH...

THE MONSOON TROUGH AXIS EXTENDS FROM 9N18W TO 8N26W TO 12N42W. THE ITCZ AXIS STRETCHES FROM 11N47W TO 10N55W. ASIDE FROM CONVECTION ASSOCIATED WITH THE TROPICAL WAVES...SCATTERED MODERATE CONVECTION IS SEEN ON EITHER SIDE OF THE TROUGH AXIS FROM 06N-10N BETWEEN 25W-31W.


...DISCUSSION...

GULF OF MEXICO...

A BROAD AND ELONGATED MID TO UPPER-LEVEL LOW IS SPINNING OVER THE NORTH-CENTRAL GULF NEAR 20N89W. A TROUGH EXTENDS FROM THE LOW CENTER TO NEAR 20N97W. NORTHERLY WINDS AND A DRY AIR MASS IN THE MID-UPPER ATMOSPHERE IS NOTED ON WATER VAPOR IMAGERY BEHIND THE TROUGH AXIS WHILE SOUTHWESTERLY FLOW AHEAD OF THE TROUGH AXIS CONTINUES TO ADVECT ABUNDANT MID-UPPER LEVEL MOISTURE ACROSS THE EASTERN GULF INTO THE FLORIDA PENINSULA AND THE SE CONUS. THE TROUGHING SUPPORTS A SURFACE TROUGH THAT EXTENDS FROM NORTHERN FLORIDA TO 29N86W TO 26N90W AT 1500 UTC. A BAND OF SHOWERS WITH EMBEDDED TSTMS IS OVER THE EASTERN GULF WATERS AND SE OF THE TROUGH AXIS COVERING MAINLY THE AREA N OF 25N E OF 88W. ANOTHER SURFACE TROUGH IS OVER THE SW GULF EXTENDING FROM 22N96W TO 19N95W SCATTERED SHOWERS AND ISOLATED TSTMS ARE S OF 21N W OF 92W. THE REMNANT LOW OF ERICA IS FORECAST TO MOVE TO NEAR 24N81W EARLY SUN AND TO NEAR 27N84W EARLY MON. THE MAIN IMPACT WILL BE HEAVY RAINFALL ACROSS PARTS OF SOUTH AND CENTRAL FLORIDA AND WILL ALSO BRING AND INCREASE IN WINDS AND SEAS OVER THE E GULF. PLEASE SEE SPECIAL FEATURES FOR MORE DETAILS.

CARIBBEAN SEA...

THE REMNANTS OF ERICA ARE N OF AREA NEAR THE NORTHERN COAST OF EASTERN CUBA AND ARE EXPECTED TO PRODUCE TOTAL RAINFALL ACCUMULATIONS OF 3-6 INCHES WITH MAXIMUM AMOUNTS OF 10 INCHES POSSIBLE ACROSS PORTIONS OF HISPANIOLA AND EASTERN AND CENTRAL CUBA THROUGH SUNDAY RESULTING IN LIFE-THREATENING FLASH FLOODS AND DANGEROUS MUD SLIDES. PLEASE REFER TO THE SECTION ABOVE FOR DETAILS. THE MOST RECENT SCATTEROMETER PASSES SHOW MODERATE TO FRESH TRADE WINDS ACROSS PARTS OF THE EASTERN AND CENTRAL CARIBBEAN...PARTICULARLY BETWEEN 68W AND 76W. THESE WINDS WILL PERSIST ON SUN. SCATTERED SHOWERS AND ISOLATED TSTMS ARE AFFECTING THE LESSER ANTILLES...MAINLY S OF GUADELOUPE AHEAD OF A TROPICAL WAVE NOW APPROACHING THE AREA FROM THE E. THE CHANCE OF SHOWERS AND TSTMS WILL PERSIST ACROSS THE LESSER ANTILLES THROUGH SUN AS THE WAVE MOVES ACROSS THE EASTERN CARIBBEAN. ALOFT...A RIDGE DOMINATES THE WESTERN CARIBBEAN AND EXTENDS FROM AN ANTICYCLONE LOCATED OVER NICARAGUA THROUGH W-CENTRAL CUBA INTO THE NW BAHAMAS.


...HISPANIOLA...

AS THE REMNANTS OF ERICA MOVES AWAY FROM THE AREA...EXPECT IMPROVING WEATHER CONDITIONS. LOCALLY HEAVY RAINS AND GUSTY WINDS ARE STILL EXPECTED TODAY...ESPECIALLY OVER HAITI.

ATLANTIC OCEAN...

THE REMNANTS OF TROPICAL STORM ERICA ARE LOCATED BETWEEN CUBA AND THE CENTRAL BAHAMAS BASED ON LATEST VISIBLE SATELLITE PICTURES. PLEASE SEE SPECIAL FEATURES FOR DETAILS. FRESH TO STRONG WINDS IN THE 25-30 KT RANGE ARE NOTED PER SCATTEROMETER DATA BETWEEN THE REMNANTS OF ERICA AND A 1022 MB 30N68W WITH A SMALL AREA OF MINIMAL GALE FORCE WINDS WITHIN 90 NM NE AND 120 NM E QUADRANTS. THE REMNANT LOW OF ERICA IS FORECAST TO MOVE TO NEAR 24N81W EARLY SUN. STRONG TO NEAR GALE FORCE E-SE WINDS AND SQUALLS WILL MOVE W-NW THROUGH THE BAHAMAS THIS AFTERNOON AND INTO SE FLORIDA TONIGHT AND SUN N OF THE TRACK OF THE REMNANT LOW. OTHERWISE...HIGH PRES DOMINATES THE REMAINDER OF THE ATLANTIC OCEAN ANCHORED BY A PAIR OF 1021 MB SURFACE HIGHS...THE FIRST LOCATED NEAR 25N38W AND THE OTHER CENTERED NEAR 25N45W. AN UPPER-LEVEL TROUGH CROSSES THE CANARY ISLANDS AND EXTENDS TO NEAR 25N33W. A RIDGE COVERS MUCH OF THE TROPICAL ATLC.

FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE

$$ GR

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