Tropical Weather Discussion
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000
AXNT20 KNHC 031725
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT MON AUG 03 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...

GALE FORCE WINDS ARE EXPECTED ALONG THE COAST OF COLOMBIA FROM
11N-13N BETWEEN 74W-77W UNTIL 1800 UTC THIS AFTERNOON. THESE
WINDS ARE ASSOCIATED WITH THE TIGHT PRESSURE GRADIENT BETWEEN
THE W ATLANTIC SURFACE RIDGE AND THE LOWER PRESSURE OVER SOUTH
AMERICA. PLEASE SEE THE HIGH SEAS FORECAST UNDER AWIPS/WMO
HEADERS MIAHSFAT2/FZNT02 KNHC FOR MORE DETAILS.

...TROPICAL WAVES...

A TROPICAL WAVE IS OVER THE EASTERN ATLANTIC WITH AN AXIS
EXTENDING FROM 18N35W TO 10N35W...MOVING W AT AROUND 10 KT OVER
THE PAST 24 HOURS. CURRENT MODEL GUIDANCE SHOWS A 700 MB
TROUGHING ALONG 35W. DESPITE THE FACT THAT THE WAVE IS EMBEDDED
IN HIGH MOISTURE MAINLY S OF 13N...NO CONVECTION IS ASSOCIATED
TO THIS FEATURE DUE TO A BROAD SAHARAN DUST AIRMASS THAT
PREVAILS ACROSS THE TROPICAL ATLANTIC INHIBITING SIGNIFICANT
CONVECTION.

A TROPICAL WAVE IS OVER THE CENTRAL ATLANTIC WITH AXIS EXTENDING
FROM 21N45W TO 10N46W...MOVING W AT AT 10 TO 15 KT. THIS WAVE
COINCIDES WITH A 700 MB TROUGH BETWEEN 35W AND 45W. TPW IMAGERY
SHOWS A DRY ENVIRONMENT SURROUNDING THIS WAVE AND WITH SAHARAN
DUST ALSO PREVAILING...NO SIGNIFICANT CONVECTION IS DEVELOPING
AT THIS TIME ACROSS THIS AREA.

A TROPICAL WAVE IS OVER THE CENTRAL CARIBBEAN WITH AN AXIS
EXTENDING ACROSS HISPANIOLA FROM 20N71W TO 13N72W...MOVING W AT
15 TO 20 KT OVER THE PAST 24 HOURS. THIS WAVE COINCIDES WITH 700
MB TROUGHING BETWEEN 70W AND 80W AND VISIBLE IMAGERY DEPICTS
FAIRLY CLEAR THE CHARACTERISTIC INVERTED V S OF HISPANIOLA. NO
CONVECTION IS RELATED TO THIS WAVE AT THIS TIME.

...ITCZ/MONSOON TROUGH...

THE MONSOON TROUGH AXIS EXTENDS ACROSS AFRICA INTO THE E
TROPICAL ATLANTIC NEAR 18N16W TO 14N31W...THEN RESUMES W OF A
TROPICAL WAVE NEAR 12N37W TO 12N45W. THE ITCZ BEGINS W OF A
TROPICAL WAVE NEAR 11N48W TO 11N60W. ISOLATED MODERATE
CONVECTION PREVAILS S OF THE MONSOON TROUGH AXIS FROM 07N-14N
AND W OF 23W AND FROM 06N-11N BETWEEN 36W-46W.

...DISCUSSION...

GULF OF MEXICO...

AN UPPER-LEVEL RIDGE IS CENTERED OVER NW MEXICO AND EXTENDS E
ACROSS THE BASIN. WITH THIS...UPPER-LEVEL DIFFLUENCE PREVAILS
ALONG THE GULF STATES COAST SUPPORTING CONVECTION N OF 28N. AT
THE SURFACE...A 1009 MB LOW IS CENTERED OVER NORTHERN FLORIDA
30N83W. A SURFACE TROUGH EXTENDS FROM THE LOW CENTER TO NEAR
26N87W. THE COMBINATION OF DEEP MOISTURE...LOW-LEVEL
CONVERGENCE...AND THE UPPER DIFFLUENCE PREVIOUSLY MENTIONED
SUPPORTS NUMEROUS SHOWERS AND THUNDERSTORMS ACROSS THE EASTERN
HALF OF THE BASIN MAINLY E OF 87W. THE REMAINDER OF THE BASIN
CONTINUES CONVECTION FREE WITH THE SURFACE RIDGE THAT PREVAILS
ACROSS THE ATLANTIC EXTENDING W REACHING THE GULF WATERS. A
GENTLE TO MODERATE ANTICYCLONIC FLOW IS OBSERVED IN
SCATTEROMETER DATA ACROSS THE GULF. OVER THE NEXT 24
HOURS...EXPECT FOR CONVECTION TO CONTINUE ACROSS THE NORTH AND
EAST GULF AS THE SURFACE LOW CONTINUES IN THE VICINITY.

CARIBBEAN SEA...

AN UPPER-LEVEL LOW IS CENTERED OVER E CUBA NEAR 21N76W WITH
CYCLONIC FLOW ALOFT COVERING THE WHOLE BASIN. TPW IMAGERY
DEPICTS A MOIST ENVIRONMENT PREVAILING OVER THE WESTERN
CARIBBEAN THAT COMBINED WITH THIS UPPER LOW...ARE ENHANCING
CLOUDINESS AND ISOLATED CONVECTION ACROSS PORTIONS OF CUBA AND
THE W CARIBBEAN MAINLY N OF 18N AND W OF 75W. TO THE E...A
TROPICAL WAVE IS MOVING OVER HISPANIOLA AHEAD OF A SAHARAN
AIRMASS THAT CONTINUES INHIBITING CONVECTION ACROSS THE E
CARIBBEAN MAINLY E OF 72W. SCATTEROMETER DATA DEPICTS GENTLE TO
MODERATE TRADES ACROSS THE BASIN WITH HIGHER SPEEDS S OF 14N
BETWEEN 74W-77W. PLEASE REFER TO THE SPECIAL FEATURES SECTION
FOR MORE DETAILS. OVER THE NEXT 24 HOURS...CONVECTION WILL
REMAIN POSSIBLE OVER THE NW CARIBBEAN AS THE TROPICAL WAVE
CONTINUES MOVING W.

...HISPANIOLA...

A TROPICAL WAVE IS MOVING ACROSS THE ISLAND WITH AXIS CURRENTLY
ALONG 71W. ISOLATED MODERATE CONVECTION IS EXPECTED AS THE WAVE
CONTINUES MOVING W. A SAHARAN AIRMASS PREVAILS BEHIND THIS WAVE
THEREFORE...DRY WEATHER CONDITIONS ARE EXPECTED AFTER THE WAVE
MOVES THROUGH.

ATLANTIC OCEAN...

A 1009 MB SURFACE LOW IS MOVING NE ACROSS NORTHERN FLORIDA. A
STATIONARY FRONT EXTENDS FROM THE LOW ACROSS THE NW ATLANTIC
SUPPORTING CONVECTION N OF 32N. TO THE E...A SURFACE TROUGH
EXTENDS FROM 24N71W TO 29N66W. SCATTERED MODERATE CONVECTION IS
OBSERVED FROM 22N-30N BETWEEN 67W-72W. A SURFACE RIDGE PREVAILS
ACROSS THE REMAINDER OF THE BASIN ANCHORED BY A 1025 MB SURFACE
HIGH NEAR 33N55W AND A 1020 MB HIGH CENTERED NEAR 31N18W. A
BROAD AREA OF SAHARAN DUST CONTINUES TO INHIBIT ANY SIGNIFICANT
CONVECTION ACROSS THE BASIN. OVER THE NEXT 24 HOURS...EXPECT FOR
CONVECTION TO CONTINUE FROM THE BAHAMAS TO THE N FL COAST AS THE
SURFACE LOW CONTINUES IN THE VICINITY. ISOLATED CONVECTION IS
ALSO EXPECTED ALONG THE SURFACE TROUGH AS IT MOVES NW OVER THE W
ATLANTIC.

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

$$

ERA



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