[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 281035
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1030 UTC.

...SPECIAL FEATURES...

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

A GALE WARNING IS IN EFFECT FOR AN AREA FROM 11.5N-14N BETWEEN
73W-71W. SEAS OF 12 TO 18 FT CAN BE EXPECTED WITHIN 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 SW CARIBBEAN SEA AND SOUTH AMERICA. 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 11N42W TO 03N43W...MOVING W AT 20 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
08N BETWEEN 42W-44W.

A TROPICAL WAVE IS ACROSS THE E CARIBBEAN...WITH AXIS EXTENDING
FROM 18N65W TO 10N65W. THIS WAVE IS MOVING W AT 15 TO 20 KT.
SSMI TPW IMAGERY SHOWS THIS WAVE ALSO EMBEDDED IN DEEP MOISTURE
MAINLY S OF 13N BUT A HIGH CONCENTRATION OF SAHARAN DUST
PREVAILS N OF 13N INHIBITING SIGNIFICANT CONVECTION.

A TROPICAL WAVE MOVING ACROSS THE CENTRAL CARIBBEAN WITH AXIS
EXTENDING FROM 20N74W TO 10N76W...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 WILL
SUPPORT ISOLATED CONVECTION ACROSS PORTIONS OF HISPANIOLA AND
THE WINDWARD PASSAGE. 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 14N17W TO 07N36W...WHERE THE ITCZ BEGINS AND
CONTINUES TO 07N41W...THEN RESUMES W OF A TROPICAL WAVE NEAR
07N45W TO 05N53W. SCATTERED MODERATE CONVECTION IS WITHIN 50 NM
OF THE ITCZ AND MONSOON TROUGH AXES MAINLY E OF 30W...AND WITHIN
50 NM OF THE ITCZ AXIS BETWEEN 50W-53W.

...DISCUSSION...

GULF OF MEXICO...

AN UPPER-LEVEL LOW IS CENTERED OVER THE WESTERN GULF NEAR 25N94W
WHILE AN UPPER-LEVEL ANTICYCLONE IS CENTERED OVER THE FLORIDA
STRAITS. THESE FEATURES ARE GENERATING A DIFFLUENT FLOW ACROSS
THE CENTRAL GULF WHICH SUPPORTS CLOUDINESS AND ISOLATED
CONVECTION BETWEEN 87W-95W. AT THE SURFACE...A 1018 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. THE SURFACE HIGH WILL
REMAIN STATIONARY OVER THE SE GULF.

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
MINIMAL GALE FORCE WINDS PREVAILING OVER THE S-CENTRAL
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 MOVES
THROUGH PUERTO RICO AND APPROACHES HISPANIOLA.

...HISPANIOLA...

A TROPICAL WAVE IS CURRENTLY OVER THE WINDWARD PASSAGE AND THE
MOIST AIRMASS BEHIND IT PREVAILS ACROSS THE AREA. DESPITE
THIS...FAIR WEATHER PREVAILS OVER THE ISLAND THIS MORNING. AN
UPPER-LEVEL TROUGH EXTENDS FROM THE SW ATLANTIC ACROSS THE
WINDWARD PASSAGE. WITH THIS...EXPECT CONVECTION TO DEVELOP 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 MODERATE CONVECTION S
OF 26N BETWEEN 64W-72W. A 1026 MB SURFACE HIGH PREVAILS ACROSS
THE REMAINDER OF THE BASIN CENTERED NEAR 27N52W. A LARGE SAHARAN
AIRMASS ALSO COVERS THE AREA MAINLY N OF 09N. 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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