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Atlantic Tropical Weather Discussion (Text)



000
AXNT20 KNHC 020027 CCA
TWDAT 

TROPICAL WEATHER DISCUSSION...CORRECTED
NWS NATIONAL HURRICANE CENTER MIAMI FL 
805 PM EDT TUE SEP 01 2015

CORRECTED FOR THE SECTION ABOUT HISPANIOLA

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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
2315 UTC.

...SPECIAL FEATURES...                                   

THE CENTER OF TROPICAL STORM FRED AT 01/2100 UTC IS NEAR 18.8N 
28.1W. FRED IS MOVING TOWARD THE WEST-NORTHWEST...OR 300 
DEGREES...10 KNOTS. THE MINIMUM CENTRAL PRESSURE IS 1003 MB. THE 
MAXIMUM SUSTAINED WIND SPEEDS ARE 45 KNOTS WITH GUSTS TO 55 
KNOTS. PUBLIC ADVISORIES ABOUT TROPICAL STORM FRED ARE BEING 
ISSUED UNDER THE WMO HEADER  WTNT31 KNHC...AND UNDER THE AWIPS 
HEADER MIATCPAT1. FORECAST/ADVISORIES ABOUT TROPICAL STORM FRED 
ARE BEING ISSUED UNDER THE WMO HEADER WTNT21 KNHC...AND UNDER 
THE AWIPS HEADER MIATCMAT1. CONVECTIVE PRECIPITATION...SCATTERED 
TO NUMEROUS STRONG WITHIN A 60 NM TO 75 NM RADIUS OF THE CENTER. 
UPPER LEVEL ANTICYCLONIC OUTFLOW IS SENDING MIDDLE LEVEL AND 
HIGH LEVEL CLOUDS TOWARD THE NORTHEAST...AWAY FROM FRED... 
COVERING THE ATLANTIC OCEAN ELSEWHERE FROM 20N TO 27N BETWEEN 
AFRICA AND 32W.

...TROPICAL WAVES...                                         

AN ATLANTIC OCEAN TROPICAL WAVE IS ALONG 40W/41W FROM 20N 
SOUTHWARD...MOVING WESTWARD 10 TO 15 KNOTS. SCATTERED TO BROKEN 
LOW LEVEL AND MIDDLE LEVEL CLOUDS AND POSSIBLE RAINSHOWERS ARE 
FROM 13N TO 20N BETWEEN 39W AND 45W.  

A CARIBBEAN SEA TROPICAL WAVE CURVES FROM 20N65W TO 16N68W AND 
TO 12N70W. THE WAVE IS MOVING WESTWARD 15 KNOTS. THIS WAVE IS 
MOVING THROUGH AN AREA OF UPPER LEVEL ANTICYCLONIC WIND FLOW... 
THAT IS TO THE EAST OF A CARIBBEAN SEA 18N78W MIDDLE LEVEL TO 
UPPER LEVEL CYCLONIC CIRCULATION CENTER. CONVECTIVE 
PRECIPITATION...SCATTERED TO NUMEROUS STRONG IN THE COASTAL 
PLAINS/COASTAL WATERS OF COLOMBIA FROM 10N TO THE COAST BETWEEN 
THE COLOMBIA/VENEZUELA BORDER AND 75W. 

A TROPICAL WAVE IS ALONG 16N84W...THROUGH EASTERN HONDURAS AND 
EASTERN NICARAGUA...TO SOUTHERN COSTA RICA NEAR 09N83W. THIS 
WAVE ALSO IS MOVING THROUGH THE SAME AREA OF CYCLONIC WIND FLOW 
THAT HAS BEEN GENERATED BY THE 18N78W CYCLONIC CIRCULATION 
CENTER. THE MONSOON TROUGH IS ALONG 08N/09N BETWEEN 77W AND 
BEYOND SOUTHERN COSTA RICA. CONVECTIVE PRECIPITATION...SCATTERED 
STRONG FROM THE COAST OF PANAMA NEAR 09N TO 11N BETWEEN 79W AND 
81W. WIDELY SCATTERED TO SCATTERED MODERATE AND ISOLATED STRONG 
IN CENTRAL AMERICA FROM NICARAGUA TO THE YUCATAN PENINSULA 
BETWEEN 85W AND 93W IN SOUTHERN MEXICO.

...ITCZ/MONSOON TROUGH...                                     

THE MONSOON TROUGH IS ALONG 12N31W 09N41W 07N50W. THE ITCZ 
CONTINUES FROM 07N50W INTO NORTHWESTERN FRENCH GUIANA...ACROSS 
THE NORTHERN PART OF SURINAME...THROUGH CENTRAL GUYANA...ACROSS 
A BIT OF BRAZIL...INTO VENEZUELA NEAR 05N62W. CONVECTIVE 
PRECIPITATION...SCATTERED STRONG FROM 08N TO 10N BETWEEN 36W AND 
37W. ISOLATED MODERATE IS WITHIN 60 NM TO 90 NM ON EITHER SIDE 
OF THE LINE FROM 14N25W TO 10N34W TO 08N46W AND 07N59W. 

...DISCUSSION...

THE GULF OF MEXICO...                                            

UPPER LEVEL SOUTHERLY WIND FLOW SPANS THE GULF OF MEXICO FROM 
92W EASTWARD. THIS WIND FLOW IS ASSOCIATED WITH BROAD UPPER 
LEVEL CYCLONIC WIND FLOW...THAT IS CONNECTED WITH AN EAST TEXAS 
CYCLONIC CIRCULATION CENTER THAT IS NEAR 32N96W. A TROUGH 
CONTINUES FROM THE 32N96W EAST TEXAS CENTER...TO 23N94W AND TO 
SOUTHERN MEXICO NEAR 19N92W. CONVECTIVE PRECIPITATION...WIDELY 
SCATTERED MODERATE TO ISOLATED STRONG TO THE NORTHWEST OF THE 
LINE THAT RUNS FROM 23N97W ALONG THE MEXICO GULF COAST...BEYOND 
SOUTHEASTERN LOUISIANA. ISOLATED MODERATE ELSEWHERE FROM 24N 
NORTHWARD...INTO PARTS OF SOUTHWESTERN FLORIDA...TO THE 
SOUTHWEST OF LAKE OKEECHOBEE. 

A SURFACE TROUGH IS ALONG THE LINE FROM THE FLORIDA BIG BEND 
NEAR 30N84W TO A 1017 MB LOW PRESSURE CENTER THAT IS NEAR 
28N85W...TO 26N87W. THIS TROUGH AND LOW PRESSURE CENTER 
COMBINATION REPRESENTS THE REMNANTS OF ERIKA. 

THE CARIBBEAN SEA...

A MIDDLE LEVEL TO UPPER LEVEL CYCLONIC CIRCULATION CENTER IS 
NEAR 18N78W. CYCLONIC WIND FLOW THAT IS MOVING AROUND THE CENTER 
COVERS THE AREA FROM 72W WESTWARD. TWO TROPICAL WAVES ARE MOVING 
THROUGH THE AREA OF THE CYCLONIC WIND FLOW THAT IS MOVING AROUND 
THE 18N78W CYCLONIC CENTER. PLEASE READ THE SECTION ABOUT 
TROPICAL WAVES FOR MORE DETAILS.

THE SOUTHERN END OF A MIDDLE LEVEL TO UPPER LEVEL TROUGH 
CONTINUES FROM A MIDDLE LEVEL TO UPPER LEVEL CYCLONIC 
CIRCULATION CENTER THAT IS NEAR 20N63W....INTO THE SOUTHEASTERN 
CORNER OF THE CARIBBEAN SEA TOWARD TRINIDAD AND NORTHEASTERN 
VENEZUELA. TWO TROPICAL WAVES ARE MOVING THROUGH

THE 24-HOUR RAINFALL TOTALS IN INCHES FOR THE PERIOD ENDING AT 
01/1200 UTC...ACCORDING TO THE PAN AMERICAN TEMPERATURE AND 
PRECIPITATION TABLES...MIATPTPAN/SXCA01 KNHC...ARE 1.06 IN 
BERMUDA...0.66 IN GUADELOUPE...0.53 IN MERIDA MEXICO...AND 0.10 
IN ST. THOMAS. 

...HISPANIOLA...                                               

A CARIBBEAN SEA TROPICAL WAVE CURVES FROM 20N65W TO 16N68W AND 
TO 12N70W. THE WAVE IS MOVING WESTWARD 15 KNOTS. THIS WAVE IS 
MOVING THROUGH AN AREA OF UPPER LEVEL ANTICYCLONIC WIND FLOW... 
THAT IS TO THE EAST OF A CARIBBEAN SEA 18N78W MIDDLE LEVEL TO 
UPPER LEVEL CYCLONIC CIRCULATION CENTER. THE TROPICAL WAVE 
SHOULD BE REACHING HISPANIOLA DURING THE NEXT 24 HOURS OR LESS.

CURRENT CONDITIONS...IN PORT-AU-PRINCE HAITI...RAINSHOWERS WITH 
THUNDER. IN THE DOMINICAN REPUBLIC...SCATTERED LOW LEVEL CLOUDS 
IN BARAHONA. FEW CUMULONIMBUS CLOUDS AND A HIGH LEVEL CLOUD 
CEILING ARE IN SANTO DOMINGO. FEW LOW LEVEL CLOUDS ARE IN LA 
ROMANA. RAINSHOWERS ARE BEING OBSERVED IN PUNTA CANA. FEW LOW 
LEVEL CLOUDS ARE IN SANTIAGO. FEW LOW LEVEL CLOUDS AND SCATTERED 
HIGH LEVEL CLOUDS ARE IN PUERTO PLATA.

THE GFS MODEL FORECAST FOR 250 MB SHOWS THAT HISPANIOLA STARTS 
IN THE MIDDLE OF THE CURRENT 18N78W CYCLONIC CIRCULATION CENTER 
AND A NORTHEAST-TO-SOUTHWEST ORIENTED TROUGH THAT REACHES 
HISPANIOLA FROM THE ATLANTIC OCEAN. THE TROUGH IS CONNECTED TO 
THE 20N63W ATLANTIC OCEAN CYCLONIC CIRCULATION CENTER. THIS 
SITUATION CONTINUES FOR THE FIRST 24 HOURS OR SO. NORTHEASTERLY 
WIND FLOW EVENTUALLY MOVES ACROSS THE AREA FOR DAY TWO OF THE 48-
HOUR FORECAST PERIOD. THE GFS MODEL FORECAST FOR 500 MB STARTS 
WITH AN INVERTED TROUGH MOVING ACROSS THE AREA AND SOUTHEASTERLY 
WIND EVERYWHERE. THE TROUGH MOVES AWAY FROM THE AREA...FOLLOWED 
BY INTERMITTENT PERIODS OF EAST-TO-NORTHEAST WIND FLOW FOR THE 
REST OF THE 48-HOUR FORECAST TIME. THE GFS MODEL FOR 700 MB 
SHOWS THAT AN INVERTED TROUGH WILL MOVE ACROSS THE AREA FOR THE 
FIRST 24 TO 30 HOURS. SOUTHEASTERLY WIND FLOW EVENTUALLY WILL 
COVER THE AREA FOR THE REST OF DAY TWO...AS AN ANTICYCLONIC 
CIRCULATION CENTER MOVES TO EASTERN PUERTO RICO. 

THE ATLANTIC OCEAN...                                            

A MIDDLE LEVEL TO UPPER LEVEL INVERTED TROUGH EXTENDS FROM THE 
NORTHERN BAHAMAS TO SOUTHEASTERN CUBA. THE TROUGH EVENTUALLY 
CONTINUES SOUTHWARD TO PANAMA IN THE SOUTHWESTERN CORNER OF THE 
CARIBBEAN SEA. COMPARATIVELY DRIER AIR IN SUBSIDENCE SURROUNDS 
THE INVERTED TROUGH AT THIS MOMENT.

A MIDDLE LEVEL TO UPPER LEVEL TROUGH PASSES THROUGH 32N38W TO 
28N42W 24N45W 22N50W...CONTINUING TO 21N56W...AND TO A MIDDLE 
LEVEL TO UPPER LEVEL CYCLONIC CIRCULATION CENTER THAT IS NEAR 
20N63W. THE TROUGH CONTINUES INTO THE SOUTHEASTERN CORNER OF THE 
CARIBBEAN SEA TOWARD TRINIDAD AND NORTHEASTERN VENEZUELA. A 
SURFACE TROUGH IS IN THE ATLANTIC OCEAN ALONG 32N38W 29N40W 
25N43W. CONVECTIVE PRECIPITATION...IN THE ATLANTIC OCEAN... 
ISOLATED MODERATE TO LOCALLY STRONG FROM 17N NEAR PUERTO RICO TO 
23N IN THE ATLANTIC OCEAN BETWEEN 56W AND 66W. ISOLATED MODERATE 
WITHIN 150 NM ON EITHER SIDE OF THE LINE THAT PASSES THROUGH 
32N33W TO 25N40W...AND WITHIN 250 NM ON EITHER SIDE OF THE 
LINE FROM 25N40W TO 22N53W. 

ONE SURFACE TROUGH IS ALONG 32N50W 30N50W 28N51W. A SECOND 
SURFACE TROUGH PASSES THROUGH 32N56W 29N59W 28N63W. UPPER LEVEL 
ANTICYCLONIC WIND FLOW IS ON TOP OF THE AREAS OF THE TWO SURFACE 
TROUGHS...TO THE NORTH AND NORTHWEST OF THE LINE THAT PASSES 
THROUGH 32N44W 27N49W 25N61W 26N75W 26N80W. CONVECTIVE 
PRECIPITATION...ISOLATED MODERATE IN THE AREA OF ANTICYCLONIC 
WIND FLOW TO THE NORTHWEST OF THE 32N44W 26N80W LINE. A SURFACE 
RIDGE EXTENDS FROM A 1021 MB HIGH PRESSURE CENTER THAT IS NEAR 
30N68W...TO 23N57W AND 21N44W. A SECOND SURFACE RIDGE PASSES 
THROUGH 32N23W TO 28N31W AND 22N38W.

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

$$
MT

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Page last modified: Wednesday, 02-Sep-2015 00:27:58 UTC