[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 160538
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
205 AM EDT THU JUL 16 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.

...TROPICAL WAVES...

A TROPICAL WAVE IS OVER THE CENTRAL ATLANTIC WITH AXIS
APPROXIMATELY ALONG 34W FROM 09N TO 19N MOVING W AT 20-25 KT.
TPW IMAGERY INDICATES THE WAVE IS EMBEDDED IN A DEEP MOIST
ENVIRONMENT MAINLY E OF THE WAVE AXIS. METEOSAT SAL IMAGERY SHOW
SAHARAN DRY AIR ALSO IN THE ENVIRONMENT OF THE WAVE MAINLY ALONG
THE NORTHERN HALF OF IT WHICH REMAINS CONVECTION-FREE. SCATTERED
MODERATE CONVECTION IS S OF 12N BETWEEN 31W-35W SUPPORTED BY
UPPER-LEVEL DIVERGENCE.

A LARGE AMPLITUDE TROPICAL WAVE IS MOVING OVER THE WINDWARD
ISLANDS WITH AXIS APPROXIMATELY ALONG 61W BETWEEN 06N AND 20N
...MOVING AT 20 KT. SSMI TPW AND METEOSAT IMAGERY DEPICT A
MODERATELY MOIST ENVIRONMENT SURROUNDING THIS WAVE BUT UPPER-
LEVEL SUBSIDENCE AND SAHARAN DUST ARE KEEPING THIS AREA WITHOUT
ANY SIGNIFICANT CONVECTION AT THIS TIME.

A TROPICAL WAVE IS OVER THE W CARIBBEAN WITH AXIS APPROXIMATELY
ALONG 79W BETWEEN 11N AND 18N...MOVING W AT 15-20 KT. SSMI TPW
IMAGERY INDICATE THE WAVE IS EMBEDDED IN A MODERATELY MOIST
ENVIRONMENT. A DIFFLUENT FLOW ALOFT IS SUPPORTING CLOUDINESS AND
ISOLATED CONVECTION OVER THE NORTHERN PORTION OF THE WAVE N OF
16N WHILE THE PRESENCE OF THE MONSOON TROUGH AXIS OVER THE
SOUTHERN PORTION OF THE WAVE IS SUPPORTING SCATTERED MODERATE
CONVECTION S OF 11N.

...ITCZ/MONSOON TROUGH...

THE MONSOON TROUGH ENTERS THE ATLANTIC OCEAN THROUGH GUINEA
BISSAU NEAR 13N17W CONTINUING TO 12N19W. THE ITCZ EXTENDS FROM
THAT POINT TO 11N30W THEN RESUMES W OF A TROPICAL WAVE NEAR
10N35W TO 06N47W TO 08N59W. ASIDE FROM THE CONVECTION ASSOCIATED
WITH THE TROPICAL WAVES...SCATTERED MODERATE CONVECTION IS
OBSERVED FROM 05N-12N BETWEEN 35W-43W.

...DISCUSSION...

GULF OF MEXICO...

A BROAD SURFACE RIDGE COVERS A LARGE PORTION OF THE ATLANTIC
BASIN AND EXTENDS WESTWARD ACROSS SOUTH FLORIDA AND THE STRAITS
OF FLORIDA REACHING THE GULF OF MEXICO. A WEAK 1016 MB SURFACE
HIGH IS CENTERED NEAR 26N88W. A WEAK SURFACE TROUGH IS OVER THE
BAY OF CAMPECHE EXTENDING FROM 22N95W TO 18N94W. THE CONVECTION
OF A SQUALL LINE THAT CURRENTLY IS MOVING OVER MISSISSIPPI AND
ALABAMA IS REACHING THE NE GULF MAINLY N OF 28N. ALOFT...AN
ELONGATED UPPER-LEVEL LOW IS CENTERED OVER THE ISTHMUS OF
TEHUANTEPEC EXTENDS INTO THE BAY OF CAMPECHE PROVIDING
SUPPORTING SCATTERED CONVECTION S OF 21N BETWEEN 91W-95W. A MID
TO UPPER-LEVEL ANTICYCLONE OVER E TEXAS WITH RIDGE AXIS
EXTENDING SE ACROSS THE GULF TO NORTHERN FLORIDA. DEEP LAYERED
SUBSIDENCE PREVAILS OVER THE NW GULF SUPPORTING FAIR WEATHER.
SCATTEROMETER DATA DEPICTS A LIGHT ANTICYCLONIC FLOW PREVAILING
ACROSS THE BASIN. SURFACE RIDGING AND LIGHT FLOW WILL BE THE
DOMINANT FEATURE DURING THE NEXT FEW DAYS.

CARIBBEAN SEA...

A TROPICAL WAVE IS OVER THE W CARIBBEAN. PLEASE REFER TO THE
SECTION ABOVE FOR MORE DETAILS. STRONG DEEP LAYER WIND SHEAR
INHIBITS CONVECTION ACROSS THE MAJORITY OF THE BASIN. OVER THE
SW CARIBBEAN...THE PRESENCE OF THE MONSOON TROUGH SUPPORTS
SCATTERED MODERATE CONVECTION S OF 11N BETWEEN 75W-80W. A
SAHARAN AIRMASS ENGULFING THE NEXT TROPICAL WAVE TO ENTER THE
BASIN COVERS THE E CARIBBEAN E OF 70W...THUS INHIBITING
CONVECTION. SCATTEROMETER DATA DEPICTS LIGHT TO GENTLE TRADES
ACROSS THE W CARIBBEAN W OF 80W. A PRESSURE GRADIENT BETWEEN
RIDGE OF HIGH PRESSURE OVER THE ATLANTIC EXTENDING ACROSS THE
NORTHERN BASIN AND LOWER PRESSURE OVER SOUTH AMERICA SUPPORTS
FRESH TO STRONG TRADE WINDS ACROSS THE CENTRAL CARIBBEAN MAINLY
S OF 16N BETWEEN 70W-79W. FRESH TRADES PREVAIL ACROSS THE BASIN
MAINLY E OF 80W. THE NEXT TROPICAL WAVE WILL ENTER THE E
CARIBBEAN TONIGHT POSSIBLY ENHANCING SHOWERS OVER THE LESSER
ANTILLES AND PUERTO RICO.

HISPANIOLA...

FAIR WEATHER PREVAILS ACROSS THE ISLAND AT THIS TIME. TPW
IMAGERY DEPICTS A PATCH OF DRIER AIR OVER PUERTO RICO AND THE
DOMINICAN REPUBLIC AND UPPER-LEVEL SUBSIDENCE ALSO PREVAILS OVER
THIS AREA. THIS WILL LIMIT CONVECTION OVER THE NEXT 24 HOURS.

ATLANTIC OCEAN...

TWO TROPICAL WAVES ARE OVER THE TROPICAL ATLANTIC ALONG 32W AND
59W. PLEASE SEE THE TROPICAL WAVES SECTION ABOVE FOR MORE
DETAILS. THE BASE OF AN UPPER-LEVEL TROUGH ALONG THE EASTERN
CONUS AND THE PRESENCE OF AN UPPER-LEVEL LOW OVER THE BAHAMAS IS
GENERATING DIFFLUENT FLOW W OF 70W. WITH THIS...CLOUDINESS AND
ISOLATED CONVECTION PREVAILS ACROSS THE W ATLANTIC. THE BERMUDA
AZORES HIGH EXTENDS A RIDGE ACROSS THE CENTRAL AND E TROPICAL
ATLANTIC SUPPORTING FAIR WEATHER. A SURFACE TROUGH EXTENDS OVER
THE N-CENTRAL ATLANTIC FROM 27N54W TO 35N41W WITH ISOLATED
CONVECTION ALONG IT.

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

$$

ERA
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