[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 101751
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT SUN MAY 10 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.

...GALE WARNING FOR SW CARIBBEAN...

A GALE WARNING HAS BEEN ISSUED FOR THE SW CARIBBEAN OFF THE
COAST OF COLOMBIA. AS HIGH PRES BUILDS N OF AREA...WINDS ARE
FORECAST TO PULSE TO MINIMAL GALE FORCE DURING THE OVERNIGHT AND
EARLY MORNING HOURS THROUGH WED NIGHT. THE MOST RECENT HIGH
RESOLUTION SCATTEROMETER PASS SHOWED GALE FORCE WINDS NEAR THE
COAST OF COLOMBIA...PARTICULARLY FROM 11N TO 13N BETWEEN 72W AND
75W. SEAS ARE FORECAST TO BUILD TO 12-15 FT WITH THE STRONGEST
WINDS.

...ITCZ/MONSOON TROUGH...

THE MONSOON TROUGH EXTENDS ACROSS AFRICA...THEN ALONG THE COAST
FROM SENEGAL TO GUINEA-BISSAU TO 10N16W TO 8N18W TO 6N23W WHERE
THE ITCZ BEGINS AND CONTINUES FROM 6N23W TO 5N40W TO INLAND OVER
SOUTH AMERICA NEAR 2N50W. SCATTERED MODERATE/ISOLATED STRONG
CONVECTION IS FROM 4N-6.5N BETWEEN 11W-15W. SCATTERED MODERATE
CONVECTION IS NOTED WITHIN 60 NM N OF THE ITCZ AXIS BETWEEN 28W-
37W AND BETWEEN 40W-43W.

...DISCUSSION...

GULF OF MEXICO...
A 1021 MB HIGH PRES IS CENTERED OVER THE NE GULF WITH A RIDGE
EXTENDING ACROSS MOST OF THE GULF REGION. MOSTLY FAIR WEATHER
PREVAILS ACROSS THE GULF UNDER THE INFLUENCE OF THIS SYSTEM. THE
PRES GRADIENT BETWEEN THE RIDGE AND LOWER PRES OVER NE MEXICO
WILL PRODUCE MODERATE TO FRESH SOUTHERLY RETURN FLOW ACROSS THE
WESTERN HALF OF BASIN. A TROUGH IS ANALYZED ON THE 1200 UTC MAP
OVER THE SW GULF AND EXTENDS FROM 22N85W TO 19N94W. THIS WEATHER
PATTERN IS FORECAST TO PERSIST OVER THE NEXT SEVERAL DAYS. A
SURFACE TROUGH WILL DEVELOP EACH AFTERNOON ACROSS THE YUCATAN
PENINSULA AND SHIFT W-NW ACROSS THE SW GULF DURING THE EVENING
AND OVERNIGHT HOURS...RESULTING IN ENHANCED WINDS AND SEAS.
ALOFT...UPPER RIDGE ANCHORED IN THE E PACIFIC REGION EXTENDS A
RIDGE AXIS ACROSS THE GULF OF MEXICO TO OVER THE SE CONUS NEAR
PANAMA CITY FLORIDA WHILE AN UPPER TROUGH IN THE W ATLC COVERS
THE FLORIDA PENINSULA.

CARIBBEAN SEA...
TRADE WINDS ARE EXPECTED TO INCREASE TO GALE FORCE ALONG THE
COAST OF COLOMBIA DURING THE OVERNIGHT HOURS...TONIGHT THROUGH
WED NIGHT. PLEASE SEE SPECIAL FEATURE FOR MORE DETAILS.
ELSEWHERE...FRESH TO STRONG TRADES WILL PREVAIL ACROSS MUCH OF
THE CARIBBEAN TODAY...THEN EXPAND WESTWARD TO THE GULF OF
HONDURAS TONIGHT THROUGH WED AS STRONG HIGH PRES BUILDS N OF
AREA. SHALLOW MOISTURE EMBEDDED IN THE TRADE WIND FLOW WILL
CONTINUE TO MOVE ACROSS THE REGION PRODUCING ISOLATED TO
SCATTERED PASSING SHOWERS. PATCHES OF MOISTURE FROM THE ATLANTIC
ARE CURRENTLY MOVING ACROSS THE WINDWARD ISLANDS. IN THE UPPER-
LEVELS...THE UPPER TROUGH OVER THE W ATLC EXTENDS INTO THE
CARIBBEAN ACROSS EASTERN CUBA TO WESTERN PANAMA. ISOLATED TO
SCATTERED SHOWERS ARE SEEN NEAR THE SOUTHERN END OF THE TROUGH
AXIS OVER THE SW CARIBBEAN. SOUTHWESTERLY WINDS ON THE EAST SIDE
OF THE TROUGH ARE TRANSPORTING MID/UPPER LEVEL MOISTURE FROM THE
E PACIFIC ACROSS COLOMBIA AND WESTERN VENEZUELA TO BEYOND PUERTO
RICO.

...HISPANIOLA...
SOUTHWESTERLY FLOW ALOFT ASSOCIATED WITH THE UPPER TROUGH OVER
THE W CARIBBEAN WILL CONTINUE TO AFFECT THE ISLAND OVER THE NEXT
COUPLE OF DAYS. THIS WILL COMBINE WITH LOW LEVEL MOISTURE TO
PRODUCE SCATTERED SHOWERS AND ISOLATED TSTMS DURING THE
AFTERNOON AND EARLY EVENING HOURS.

ATLANTIC OCEAN...
TROPICAL STORM ANA...CURRENTLY LOCATED N OF AREA...MADE LANDFALL
AT 0600 AM EDT...1000 UTC...ALONG THE COAST OF SOUTH CAROLINA
ALMOST MIDWAY BETWEEN MYRTLE BEACH AND NORTH MYRTLE BEACH. THE
STORM IS INLAND WHILE WEAKENING. ANA IS FORECAST TO BECOME A
TROPICAL DEPRESSION LATER TODAY. THIS TROPICAL CYCLONE IS
EXPECTED TO PRODUCE RAINFALL ACCUMULATIONS OF 2-4 INCHES, WITH
ISOLATED AMOUNTS OF 6 INCHES OVER EASTERN PORTIONS OF NORTH
CAROLINA AND SOUTH CAROLINA DURING THE REST OF TODAY. MAXIMUM
SUSTAINED WINDS HAVE DIMINISHED TO 40 MPH WITH HIGHER GUSTS.
SWELLS GENERATED BY ANA ARE AFFECTING PORTIONS OF THE
SOUTHEASTERN U.S. COAST AND WILL LIKELY CAUSE LIFE-THREATENING
SURF AND RIP CURRENTS. PLEASE SEE LATEST NHC ADVISORIES.

A 1032 MB HIGH PRES LOCATED N OF THE FORECAST AREA NEAR 37N56W
COVERS THE CENTRAL AND W ATLANTIC. THIS SYSTEM IS FORECAST TO
MOVE SE TO A POSITION NEAR 32N53W IN ABOUT 24 HOURS WHILE
SLIGHTLY WEAKENING. THE SAHARAN AIR LAYER TRACKING PRODUCT FROM
UW-CIMSS INDICATES AFRICAN DUST REACHING THE LESSER ANTILLES.
ALOFT...A TROUGH/RIDGE/TROUGH PATTERN DOMINATES THE AREA. AN
UPPER-LEVEL TROUGH IS OVER THE WESTERN ATLC AND EXTENDS FROM AN
UPPER-LEVEL LOW LOCATED NEAR 28N73W TO EASTERN CUBA. UPPER
DIFFLUENCE AHEAD OF THE TROUGH IS HELPING TO INDUCE SOME SHOWER
ACTIVITY MAINLY FROM 23N-25N BETWEEN 70W-74W. A LARGE UPPER
RIDGE COVERS THE REMAINDER OF THE W AND CENTRAL ATLC. AN UPPER
TROUGH N OF 28N IN THE E/CENTRAL ATLC IS SUPPORTING A COLD FRONT
THAT ENTERS THE REGION NEAR 31N32W THEN CONTINUES SW TO NEAR
26N44W WHERE IT BEGINS TO DISSIPATE. ISOLATED TO SCATTERED
SHOWERS ARE ASSOCIATED WITH THE FRONTAL BOUNDARY. A NARROW
SURFACE RIDGE COVERS THE REMAINDER OF THE ATLC S OF THE FRONT.
MAINLY MODERATE TO FRESH TRADE WINDS ARE OBSERVED ACROSS THE
TROPICAL ATLC BASED ON SCATTEROMETER DATA.

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

$$
GR
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