Tropical Weather Discussion
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000
AXNT20 KNHC 280538
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
205 AM EDT SUN JUN 28 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
0530 UTC.

...SPECIAL FEATURES...

...GALE WARNING IN THE CARIBBEAN SEA...

GALE FORCE WINDS ARE FORECAST TO RESUME TONIGHT BEGINNING AT
0600 UTC FROM 11.5N-16N BETWEEN 70W-78W. SEAS OF 11 TO 17 FT CAN
BE EXPECTED ACROSS THIS AREA. THESE WINDS ARE BEING GENERATED BY
A TIGHT PRESSURE GRADIENT BETWEEN A STRONG HIGH PRESSURE OVER
THE WESTERN ATLANTIC AND LOWER PRESSURES OVER NORTHERN COLOMBIA
AND THE SW CARIBBEAN SEA. SEE THE LATEST NWS HIGH SEAS FORECAST
UNDER AWIPS/WMO HEADERS MIAHSFAT2/FZNT02 KNHC AND THE OFFSHORE
FORECAST...MIAOFFNT3/ FZNT23 FOR MORE DETAILS.

...TROPICAL WAVES...

A TROPICAL WAVE IS OVER THE CENTRAL TROPICAL ATLANTIC WITH AXIS
EXTENDING FROM 11N41W TO 04N42W...MOVING W AT 20 TO 25 KT. SSMI
TOTAL PRECIPITABLE WATER IMAGERY INDICATES THAT THIS WAVE IS
EMBEDDED IN A DEEP MOIST ENVIRONMENT S OF 11N...WHILE A SAHARAN
AIR LAYER PREVAILS N OF 08N. ISOLATED MODERATE CONVECTION IS
OBSERVED N OF 09N BETWEEN 41W-43W.

A TROPICAL WAVE IS CURRENTLY ENTERING THE E CARIBBEAN...WITH
AXIS EXTENDING FROM 17N61W TO 09N62W. THIS WAVE IS MOVING W AT
15 TO 20 KT. SSMI TPW IMAGERY SHOWS THIS WAVE ALSO EMBEDDED IN
DEEP MOISTURE MAINLY S OF 12N AND A SAHARAN AIR LAYER TO THE N
OF 12N. NO SIGNIFICANT CONVECTION IS RELATED TO THIS WAVE.

A TROPICAL WAVE MOVING ACROSS THE CENTRAL CARIBBEAN WITH AXIS
EXTENDING FROM 20N71W TO 11N73W...MOVING W AT AROUND 15 KT.
WATER VAPOR IMAGERY INDICATES THE NORTHERN PORTION OF THE WAVE
IS INTERACTING WITH A MID-LEVEL TROUGH THAT EXTENDS ACROSS THE
NORTHERN CARIBBEAN FROM THE SW ATLANTIC. THIS INTERACTION
GENERATED ISOLATED CONVECTION ACROSS HISPANIOLA. NO DEEP
CONVECTION IS NOTED S OF THE ISLAND DUE TO THE PRESENCE OF
SAHARAN DUST.

...ITCZ/MONSOON TROUGH...

THE MONSOON TROUGH EXTENDS ACROSS AFRICA REACHING THE TROPICAL
ATLANTIC NEAR 11N16W TO 07N28W...WHERE THE ITCZ BEGINS AND
CONTINUES TO 07N39W...THEN RESUMES W OF A TROPICAL WAVE NEAR
06N43W TO 05N52W. SCATTERED MODERATE CONVECTION IS WITHIN 50 NM
OF THE ITCZ AND MONSOON TROUGH AXES MAINLY E OF 33W...AND WITHIN
50 NM OF THE ITCZ AXIS BETWEEN 45W-47W.

...DISCUSSION...

GULF OF MEXICO...

AN UPPER-LEVEL LOW IS CENTERED OVER THE WESTERN GULF NEAR 25N96W
WHILE AN UPPER-LEVEL ANTICYCLONE PREVAILS OVER THE SOUTHERN
PORTION OF THE FLORIDA PENINSULA. THESE FEATURES ARE GENERATING
A DIFFLUENT FLOW ACROSS THE CENTRAL GULF WHICH SUPPORTS
CLOUDINESS AND ISOLATED CONVECTION BETWEEN 87W-94W. AT THE
SURFACE...A 1019 MB HIGH PRESSURE IS CENTERED NEAR 25N85W
SUPPORTING A LIGHT TO GENTLE ANTICYCLONIC FLOW ACROSS THE BASIN.
SCATTERED MODERATE CONVECTION IS DEVELOPING ACROSS THE SOUTHERN
PORTIONS OF TEXAS...LOUISIANA AND MISSISSIPPI AHEAD OF A FRONTAL
SYSTEM THAT IS DIGGING SOUTHWARD ACROSS SOUTHERN US. SOME OF
THIS ACTIVITY IS REACHING THE NORTHERN GULF MAINLY N OF 29N.
OVER THE NEXT 24 HOURS...EXPECT FOR CONVECTION TO PREVAIL ACROSS
THE NORTHERN GULF AS THE FRONT CONTINUES MOVING SE.

CARIBBEAN SEA...

A DIFFLUENT ENVIRONMENT PREVAILS ACROSS THE W CARIBBEAN
SUPPORTING ISOLATED CONVECTION MAINLY W OF 85W. TO THE E...AN
UPPER-LEVEL TROUGH ORIGINATED ACROSS THE SW ATLANTIC EXTENDS SW
ACROSS THE WINDWARD PASSAGE REACHING THE NW PORTION OF THE
BASIN. THIS FEATURE IS GENERATING CLOUDINESS AND ISOLATED
CONVECTION ACROSS HISPANIOLA AND N OF THE ISLAND. TWO TROPICAL
WAVES ARE OBSERVED ACROSS THE CENTRAL AND E CARIBBEAN...FOR MORE
INFORMATION PLEASE REFER TO THE SECTION ABOVE. A STRONG PRESSURE
GRADIENT BETWEEN THE HIGH PRESSURE OVER THE WESTERN ATLANTIC AND
LOWER PRESSURES OVER S AMERICA SUPPORTS GENTLE TO MODERATE TRADE
WINDS OVER THE MAJORITY OF THE CARIBBEAN...WITH AN AREA OF
HIGHER WINDS PREVAILING OVER THE S-CENTRAL CARIBBEAN. THE
PRESSURE GRADIENT WILL TIGHTEN LATER TONIGHT WHICH WILL INCREASE
WINDS TO GALE FORCE LATE TONIGHT OVER THE SOUTHERN CARIBBEAN.
PLEASE SEE THE SPECIAL FEATURES SECTION FOR MORE DETAILS. OVER
THE NEXT 24 HOURS...EXPECT A SLIGHT INCREASE IN CONVECTION OVER
THE EASTERN CARIBBEAN AS A TROPICAL WAVE CROSSES MOVES THROUGH
THE LEEWARD ISLANDS AND PUERTO RICO.

...HISPANIOLA...

A TROPICAL WAVE IS CURRENTLY OVER THE ISLAND BRINGING A MOIST
AIRMASS TO THE AREA. DESPITE THIS...FAIR WEATHER PREVAILS ACROSS
THE AREA AT THIS MOMENT. AN UPPER-LEVEL TROUGH EXTENDS FROM THE
SW ATLANTIC ACROSS THE WINDWARD PASSAGE. THIS WILL SUPPORT
CONVECTION THIS AFTERNOON AS THIS FEATURE COMBINES WITH DIURNAL
HEATING AND OROGRAPHIC LIFTING.

ATLANTIC OCEAN...

AN UPPER-LEVEL LOW IS CENTERED ACROSS THE SW ATLANTIC NEAR
26N69W SUPPORTING CLOUDINESS AND ISOLATED CONVECTION S OF 26N
BETWEEN 63W-70W. A 1027 MB SURFACE HIGH PREVAILS ACROSS THE
REMAINDER OF THE BASIN CENTERED NEAR 29N52W. A LARGE SAHARAN
AIRMASS ALSO PREVAILS ACROSS THE ATLANTIC. WITH THIS...FAIR
WEATHER PREVAILS ACROSS THE BASIN. OVER THE NEXT 24 HOURS...
EXPECT CONVECTION TO DEVELOP OFFSHORE FL MAINLY N OF THE BAHAMAS
AS AN UPPER-LEVEL TROUGH MOVES OFF THE SE US COAST.

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

$$

ERA



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