[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 171747
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT SUN JUN 17 2012

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.

...TROPICAL WAVES...

A TROPICAL WAVE EXTENDS FROM 17N40W TO 8N41W MOVING W AT 10-15
KT. THE WAVE COINCIDES WITH A SURGE IN DEEP LAYER MOISTURE
PRESENT IN TOTAL PRECIPITABLE WATER IMAGERY. NO DEEP CONVECTION
IS CURRENTLY ASSOCIATED WITH THE WAVE. AFRICAN DUST IS SEEN ON
VIS SATELLITE PICTURE AND THE SAHARAN AIR LAYER FROM UW-CIMSS ON
THE HEELS OF THIS WAVE.

THE TROPICAL WAVE PREVIOUSLY LOCATED ACROSS THE CARIBBEAN SEA
WAS ABSORBED INTO AN AREA OF BROAD CYCLONIC WIND FLOW IN THE SW
PORTION OF THE BASIN.

...ITCZ/MONSOON TROUGH...

THE MONSOON TROUGH EXTENDS FROM 12N16W TO 8N25W. THE ITCZ BEGINS
AT 08N25W TO 8N37W THEN RESUMES W OF TROPICAL WAVE AT 8N43W TO
6N56W. ISOLATED MODERATE CONVECTION IS NOTED WITHIN 45 NM S OF
ITCZ AXIS FROM 26W TO 30W.

...DISCUSSION...

GULF OF MEXICO...
A SURFACE TROUGH EXTENDS FROM SE LOUISIANA TO 25N94W PRODUCING
SCATTERED SHOWERS AND ISOLATED TSTMS OVER THE NORTH-CENTRAL GULF
WATERS MAINLY BETWEEN 86W AND 92W. SIMILAR CONVECTION IS NOTED
OVER THE BAY OF CAMPECHE. HIGH PRES CENTERED NEAR ATLANTA GA
EXTENDS A RIDGE OVER THE FLORIDA PENINSULA AND THE NE GULF WITH
MUCH DRIER AIR PUSHING SOUTH ACROSS THE AREA. MODERATE TO FRESH
E-SE WINDS ARE NOTED BETWEEN THE HIGH AND THE TROUGH...WHICH IS
FORECAST TO REACH THE COAST OF TEXAS TONIGHT. FRESH ELY WINDS
ARE SEEN PER THE MOST RECENT ASCAT PASS NEAR THE COAST OF
YUCATAN DUE TO LOCAL EFFECTS. SW WIND FLOW ASSOCIATED WITH THE
EPAC MONSOON TROUGH IS BRINGING ABUNDANT TROPICAL MOISTURE OVER
PARTS OF SOUTH-CENTRAL MEXICO...THE BAY OF CAMPECHE AND NORTHERN
CENTRAL AMERICA WITH THE POTENTIAL OF LOCALLY HEAVY RAIN AND THE
THREAT FOR FLASH FLOODS AND MUDSLIDES...PARTICULARLY OVER THE
MOUNTAINOUS TERRAIN. ALOFT...A LONGWAVE TROUGH OVER THE W ATLC
ENTERS THE GULF REGION THROUGH THE STRAITS OF FLORIDA...THEN
CONTINUES NW TO NEAR SE LOUISIANA. MOIST CONDITIONS WILL PERSIST
OVER THE SW GULF AND NEAR THE SURFACE TROUGH.

CARIBBEAN SEA...
A LARGE AREA OF SHOWERS WITH EMBEDDED TSTMS IS FLARING UP OVER
THE EASTERN CARIBBEAN UNDER A DIFFLUENT PATTERN ALOFT BETWEEN A
LONGWAVE TROUGH THAT EXTENDS OVER THE W ATLC AND THE GULF OF
MEXICO AND A RIDGE THAT COVERS MOST OF THE CARIBBEAN SEA. A
SURFACE TROUGH...REFLECTION OF THE AFOREMENTIONED LONGWAVE
TROUGH...EXTENDS FROM THE ATLC INTO THE CARIBBEAN SEA THROUGH
THE WINDWARD PASSAGE. FRESH SE WINDS ARE BLOWING BEHIND THE
TROUGH AXIS THAT EXTENDS FROM 20N74W TO 15N76W. A 1009 MB LOW
PRES IS OVER THE SW CARIBBEAN NEAR 12N80W. THE LOW IS EXPECTED
TO MOVE TO NEAR CAPE GRACIAS A DIOS NICARAGUA IN ABOUT 24 HOURS.
MOISTURE ASSOCIATED WITH BOTH THE TROUGH AND THE LOW PRES WILL
SPREAD WWD OVER CUBA AND THE WESTERN CARIBBEAN OVER THE NEXT
COUPLE OF DAYS. EXPECT ALSO INCREASING MOISTURE OVER THE STRAITS
OF FLORIDA...THE FLORIDA KEYS AND SOUTH FLORIDA IN ASSOCIATION
WITH THESE FEATURES.

ATLANTIC OCEAN...
ALOFT...AN UPPER LEVEL LOW IS SPINNING OVER THE WESTERN ATLC
NEAR 32N66W. A TROUGH EXTENDS FROM THE LOW SW THROUGH THE
CENTRAL BAHAMAS AND THE STRAITS OF FLORIDA INTO THE GULF OF
MEXICO. THESE UPPER LEVEL FEATURES SUPPORT A 1010 MB LOW PRES
LOCATED NEAR 31N65W. A TROUGH EXTENDS FROM THE SURFACE LOW PRES
THROUGH THE SE BAHAMAS AND THE WINDWARD PASSAGE INTO THE
CARIBBEAN SEA. THE LOW PRES IS PRODUCING AN AREA OF DISORGANIZED
SHOWERS AND THUNDERSTORMS. ANY DEVELOPMENT OF THIS SYSTEM AS A
TROPICAL OR SUBTROPICAL CYCLONE IS EXPECTED TO BE SLOW TO OCCUR
AS IT MOVES N-NE AND AWAY FROM THE FORECAST AREA DURING THE NEXT
DAY OR TWO. A LARGE AREA OF SHOWERS AND TSTMS IS ALSO NOTED
WITHIN AROUND 400 NM AHEAD OF THE TROUGH AXIS. UPPER DIFFLUENT
IS HELPING TO INDUCE THIS CONVECTIVE ACTIVITY. A 1027 HIGH PRES
LOCATED NEAR 31N30W DOMINATES THE REMAINDER OF THE ATLANTIC
OCEAN PROVIDING MOSTLY FAIR CONDITIONS. MODERATE TO FRESH TRADES
CAN BE FOUND ON THE SOUTHERN PERIPHERY OF THE RIDGE. AN UPPER-
LEVEL HIGH CENTERED OVER MAURITANIA IN W AFRICA HAS A RIDGE
ENVELOPING THE CAPE VERDE ISLANDS.

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

$$
GR








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