Tropical Weather Discussion
Issued by NWS

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000
AXNT20 KNHC 281751
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
205 PM 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1715 UTC.

...SPECIAL FEATURES...
THE PRESSURE GRADIENT BETWEEN A 1027 MB HIGH CENTERED IN THE
CENTRAL ATLC NEAR 28N57W AND LOWER PRESSURE ANALYZED ACROSS
NORTHERN COLOMBIA AND PANAMA IS GENERATING NEAR GALE TO GALE
FORCE CONDITIONS ACROSS A LARGE PORTION OF THE SOUTH-CENTRAL
CARIBBEAN SEA. SEE LATEST NWS HIGH SEAS FORECAST UNDER AWIPS/WMO
HEADERS MIAHSFAT2/FZNT02 KNHC FOR MORE DETAILS.

...TROPICAL WAVES...
TROPICAL WAVE EXTENDS FROM 06N47W TO 14N45W MOVING W AT 20 KT.
THE WAVE COINCIDES WITH A 700 MB GLOBAL MODEL INDICATED TROUGH
BETWEEN 39W-48W. DUE TO THE SAHARAN AIR LAYER ACROSS MUCH OF THE
TROPICAL NORTH ATLC...NO SIGNIFICANT CONVECTION IS OCCURRING
WITH THE WAVE AT THIS TIME.

TROPICAL WAVE EXTENDS FROM 10N70W TO 19N69W MOVING W AT 15-20
KT. SSMI TOTAL PRECIPITABLE WATER IMAGERY SHOWS THE WAVE ON THE
WESTERN EXTENT OF DEEP-LAYERED MOISTURE MAINLY S OF 20N BETWEEN
66W-70W. WHILE MOISTURE IS NOTED IN THE VICINITY OF THE WAVE
AXIS...SAHARAN DUST PREVAILS ALOFT OVER MUCH OF THE CARIBBEAN
SEAS INHIBITING ANY SIGNIFICANT CONVECTION AT THIS TIME.

TROPICAL WAVE EXTENDS FROM 10N79W TO 18N78W MOVING W AT 15 KT.
THE WAVE COINCIDES WITH A DEEP-LAYERED MOISTURE MAXIMUM ACROSS
THE WESTERN CARIBBEAN SEA AS NOTED ON TOTAL PRECIPITABLE WATER
IMAGERY. WHILE SUFFICIENT LOW TO MID-LEVEL MOISTURE IS IN PLACE
TO SUPPORT CONVECTION...WATER VAPOR IMAGERY INDICATES
NORTHWESTERLY FLOW OVER THE WESTERN CARIBBEAN PROMOTING AN
OVERALL STABLE ENVIRONMENT RESULTING IN NO SIGNIFICANT
CONVECTION AT THIS TIME.

...ITCZ/MONSOON TROUGH...
THE MONSOON TROUGH EXTENDS FROM THE AFRICAN COAST NEAR 14N17W TO
09N20W TO 08N32W. THE INTERTROPICAL CONVERGENCE ZONE AXIS
EXTENDS FROM 08N32N TO 06N46W TO 06N54W. SCATTERED MODERATE
CONVECTION IS FROM 06N-10N BETWEEN 14W-31W.

...DISCUSSION...

GULF OF MEXICO...
A MIDDLE TO UPPER LEVEL LOW IS CENTERED OVER THE NE CONUS THAT
EXTENDS AN AXIS SW FROM WESTERN NEW YORK TO SW LOUISIANA. THIS
TROUGHING SUPPORTS A COLD FRONT EXTENDING FROM THE CAROLINAS SW
ACROSS THE SE CONUS INTO A 1015 MB LOW CENTERED ACROSS EASTERN
TEXAS NEAR 32N94W. THE FRONT ALONG WITH MIDDLE TO UPPER LEVEL
DIFFLUENCE SOUTHEAST OF THE UPPER LEVEL TROUGH AXIS IS
GENERATING AN AREA OF SCATTERED SHOWERS AND TSTMS N OF 28N
BETWEEN 84W-95W. THE CONVECTION IS OCCURRING ON THE NORTHERN
PERIPHERY OF A SURFACE RIDGE ANCHORED BY A 1018 MB HIGH CENTERED
NEAR 25N87W WHICH COVERS A MAJORITY OF THE BASIN. A WEAKNESS IN
THE RIDGING IS NOTED OFF THE COAST OF MEXICO AS A SURFACE TROUGH
EXTENDS FROM 22N97W TO 18N95W. THE TROUGH AXIS IS PROVIDING
FOCUS FOR WIDELY SCATTERED SHOWERS AND ISOLATED TSTMS OCCURRING
FROM 19N-23N BETWEEN 94W-98W. THE RIDGE IS FORECAST TO REMAIN
ANCHORED ACROSS THE NE GULF THROUGH WEDNESDAY.

CARIBBEAN SEA...
MOST OF THE CARIBBEAN SEA REMAINS UNDER RELATIVELY STABLE
CONDITIONS THIS AFTERNOON AS MOSTLY NORTHWEST TO WESTERLY FLOW
ALOFT PREVAILS. NEAR THE SURFACE...AN EXTENSIVE SAHARAN AIR
LAYER IS PROVIDING THE LOW-LEVEL STABILITY AS NO NOTABLE
CONVECTION IS OCCURRING AT THIS TIME. LOW-LEVEL MOISTURE AND
CLOUDINESS ARE NOTED IN THE VICINITY OF A PAIR OF TROPICAL
WAVES...HOWEVER THEY REMAIN GENERALLY BENIGN AND LACK
CONVECTION. A FEW ISOLATED SHOWERS AND TSTMS ARE OCCURRING S OF
11N W OF 80W WITHIN CLOSE PROXIMITY TO THE MONSOON TROUGH AXIS
EXTENDING FROM COSTA RICA WESTWARD INTO THE EAST PACIFIC REGION.
OTHERWISE...THE MAIN IMPACT ACROSS THE BASIN REMAINS THE STRONG
TRADES GENERALLY S OF 18N BETWEEN 65W-82W...INCLUDING NEAR GALE
TO GALE FORCE CONDITIONS NOTED WITHIN CLOSE PROXIMITY TO THE
COAST OF COLOMBIA. THE TRADES ARE FORECAST TO PERSIST THROUGH
THE UPCOMING WEEK DUE TO A FAIRLY STATIONARY RIDGE ACROSS THE
CENTRAL ATLC AND LOWER PRESSURE VALUES ANCHORED ACROSS NORTHERN
COLOMBIA.

...HISPANIOLA...
CURRENTLY...MOSTLY CLEAR SKIES PREVAIL AS A TROPICAL WAVE
CONTINUES TO MOVE THROUGH THE REGION S OF 19N ALONG 70W. WHILE
TOTAL PRECIPITABLE WATER VALUES REMAIN HIGHER THAN NORMAL WITH
THE PASSAGE OF THE TROPICAL WAVE...VERY LITTLE PRECIPITATION IS
OCCURRING WITH THE WAVE AT THIS TIME. EXAMINING THE 28/1200 UTC
SAN JUAN PUERTO RICO SOUNDING...THE LOWER-LEVELS OF THE
ATMOSPHERE ARE UNDER THE INFLUENCE OF A SAHARAN AIR LAYER
INHIBITING ANY SIGNIFICANT CONVECTION. HOWEVER...GIVEN AMPLE
DAYTIME HEATING AND INSTABILITY...ISOLATED SHOWERS AND TSTMS ARE
POSSIBLE THROUGH THE LATE AFTERNOON AND EARLY EVENING HOURS.

ATLANTIC OCEAN...
AN UPPER LEVEL RIDGE AXIS EXTENDS OVER A PORTION OF THE SW NORTH
ATLC FROM 32N75W TO OVER WESTERN CUBA NEAR 23N81W. THIS RIDGING
IS PROVIDING AN OVERALL DIFFLUENT ENVIRONMENT W OF 76W AND ALONG
WITH A SURFACE TROUGH ANALYZED FROM 27N79W TO 32N77W IS
GENERATING SCATTERED SHOWERS AND TSTMS N OF 25N BETWEEN 74W-79W.
FARTHER SOUTHEAST...AN UPPER LEVEL LOW IS CENTERED NEAR 24N69W
SUPPORTING POSSIBLE ISOLATED SHOWERS AND TSTMS FROM 23N-26N
BETWEEN 65W-73W. OTHERWISE...A 1027 MB SURFACE HIGH PREVAILS
ACROSS THE EASTERN AND CENTRAL ATLC CENTERED NEAR 28N57W WITH
MOSTLY CLEAR SKIES AND FAIR CONDITIONS NOTED.

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

$$
HUFFMAN


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