Tropical Weather Discussion
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000
AXNT20 KNHC 021803
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT THU JUL 02 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
1745 UTC.

...SPECIAL FEATURES...

GALE-FORCE WINDS ARE FORECAST ALONG THE COASTAL WATERS OF
COLOMBIA STARTING 0600 UTC FRIDAY WITH ASSOCIATED SEAS RANGING
FROM 11 TO 17 FT. PLEASE READ THE HIGH SEAS
FORECAST...MIAHSFAT2/FZNT02 KNHC...AND THE OFFSHORE
FORECAST...MIAOFFNT3/FZNT23 KNHC...FOR MORE DETAILS.

...TROPICAL WAVES...

A TROPICAL WAVE CAME OFF THE W AFRICAN COAST EARLIER THIS
MORNING...ITS AXIS IS APPROXIMATELY NEAR 18W. SSMI TPW IMAGERY
SHOW THE WAVE IS EMBEDDED IN A BULGE OF MODERATE MOISTURE THAT
ALONG WITH A DIFFLUENT ENVIRONMENT ALOFT SUPPORT SCATTERED
MODERATE CONVECTION AND TSTMS FROM 07N TO 11N E OF 20W. METEOSAT
PSEUDO-NATURAL AND SAL TRACKING IMAGERY SHOW SAHARAN DRY AIR AND
DUST ENGULFING THE WAVE...THUS LIMITING THE CONVECTION TO THE
AFOREMENTIONED REGION.

A TROPICAL WAVE IS OVER THE CENTRAL TROPICAL ATLC WITH AXIS NEAR
36W...MOVING W AT APPROXIMATELY 15 KT. SSMI TPW IMAGERY SHOW
THAT MOISTURE HAS SLIGHTLY INCREASED DURING THE LAST SEVERAL
HOURS. HOWEVER...SIMILAR TO THE WAVE DISCUSSED ABOVE...SAHARAN
DRY AIR AND DUST ENGULF THE WAVE...THUS LIMITING THE CONVECTION
TO THE ITCZ REGION FROM 05N-10N BETWEEN 33W AND 40W.

A THIRD TROPICAL WAVE IS FARTHER WEST WITH AXIS APPROXIMATELY NEAR
48W...MOVING W AT 15 KT. DRY AIR AND DUST ARE OVER THE WAVE
ENVIRONMENT...THUS HINDERING CONVECTION.

A TROPICAL WAVE IS EAST OF THE LESSER ANTILLES WITH AXIS NEAR
58W...MOVING W AT 15-20 KT. SSMI TPW IMAGERY SHOW THE WAVE IS
MAINLY IN A DRY ENVIRONMENT...EXCEPT AHEAD OF THE WAVE WHERE
MODERATE MOISTURE ENHANCES SCATTERED SHOWERS ACROSS THE WINDWARD
ISLANDS.

A TROPICAL WAVE IS OVER THE W CARIBBEAN WITH AXIS NEAR 82W
...MOVING W AT 5-10 KT. SSMI TPW IMAGERY SHOW THE WAVE IS MAINLY
EMBEDDED IN A MODERATE MOIST ENVIRONMENT...HOWEVER STRONG DEEP
LAYER WIND SHEAR INHIBITS CONVECTION AT THE TIME.

...ITCZ/MONSOON TROUGH...

THE MONSOON TROUGH PASSES THROUGH COASTAL SECTIONS OF GUINEA
NEAR 10N14W TO 09N16W. THE ITCZ BEGINS NEAR 07N21W AND CONTINUES
TO 06N34W...RESUMING W OF A TROPICAL WAVE NEAR 07N37W TO 06N50W TO
THE COAST OF GUYANA NEAR 06N57W. ASIDE THE CONVECTION ASSOCIATED
WITH THE TROPICAL WAVE...SCATTERED MODERATE CONVECTION IS FROM
05N TO 08N BETWEEN 26W AND 32W.

...DISCUSSION...

GULF OF MEXICO...

A BROAD AREA OF HIGH PRESSURE OVER THE ATLC OCEAN EXTENDS A
RIDGE AXIS W-SW ACROSS THE FLORIDA PENINSULA AND THE ENTIRE GULF
OF MEXICO WHERE THE RIDGE IS BEING ANCHORED BY A 1021 MB HIGH
NEAR 28N85W. SSMI TPW IMAGERY SHOW MODERATE MOISTURE ALONG
COASTAL WATERS OF EASTERN MEXICO THAT ALONG WITH A MIDDLE LEVEL
LOW ANCHORED OVER THE SW GULF SUPPORT HEAVY SHOWERS AND TSTMS
FROM 21N-25N W OF 96W. MODERATE MOISTURE ADVECTION FROM THE SE
CONUS...ASSOCIATED WITH A FORMER FRONT...ALONG WITH A MIDDLE TO
UPPER LEVEL TROUGH WITH BASE EXTENDING THROUGH THE CENTRAL
FLORIDA PENINSULA SUPPORT SCATTERED HEAVY SHOWERS AND TSTMS THAT
EXTEND WITHIN 20 NM OFF THE FLORIDA PANHANDLE AND REGION FROM
CLEARWATER TO FORT MYERS. SIMILAR CONVECTION IS ON THE SE GULF
FROM 24N TO 26N E OF 84W. EXCEPT THE NE GULF WHERE WINDS ARE
LIGHT AND VARIABLE...THE REMAINDER BASIN IS BEING DOMINATED BY
SE WIND FLOW OF 10 TO 15 KT. SURFACE HIGH PRESSURE AND RIDGING
WILL DOMINATE ACROSS THE BASIN THE NEXT TWO DAYS.

CARIBBEAN SEA...

GALE-FORCE WINDS ARE FORECAST ALONG THE COASTAL WATERS OF
COLOMBIA STARTING 0600 UTC FRIDAY WITH ASSOCIATED SEAS RANGING
FROM 11 TO 17 FT. FOR MORE INFORMATION SEE SPECIAL FEATURES.
OTHERWISE...THE MAIN FEATURES IN THE BASIN ARE TWO TROPICAL WAVES.
ONE TROPICAL WAVE IS MOVING ACROSS CENTRAL AMERICA AND EPAC WATERS
WITH AXIS EXTENDING N ACROSS HONDURAS TO EAST OF BELIZE.
MODERATE MOISTURE ASSOCIATED WITH THE WAVE ENHANCES SCATTERED
SHOWERS AND TSTMS S OF 19N W OF 85W. A SECOND TROPICAL WAVE IS
MOVING ACROSS THE W CARIBBEAN WITH AXIS NEAR 82W...HOWEVER
STRONG DEEP LAYER WIND SHEAR IN THIS REGION OF THE BASIN IS
INHIBITING THE DEVELOPMENT OF CONVECTION. A SAHARAN AIRMASS
CONTINUE TO MOVE ACROSS THE EASTERN AND CENTRAL BASIN...THUS
SUPPORTING HAZY CONDITIONS. DUST ASSOCIATED WITH THIS DRY
AIRMASS IS BEING REPORTED ACROSS THE LEEWARD ISLANDS AND
HISPANIOLA. A TROPICAL WAVE IS E OF THE LESSER ANTILLES AND
ENHANCES SCATTERED SHOWERS OVER THE WINDWARD ISLANDS. WINDS OF
20 TO 25 KT ARE ACROSS THE CENTRAL AND EASTERN BASIN S OF 18N
BETWEEN 64W AND 83W. TRADES OF 15 KT DOMINATE ELSEWHERE. THE TWO
TROPICAL WAVES WILL BE THE MAIN FEATURE ACROSS THE BASIN DURING
THE NEXT TWO DAYS.

...HISPANIOLA...

A SAHARAN DRY AIRMASS IS MOVING ACROSS THE EASTERN AND CENTRAL
CARIBBEAN INCLUDING HISPANIOLA WHERE DUST IS BEING REPORTED.
FAIR WEATHER IS FORECAST THROUGH THE WEEKEND AS THIS LARGE
TONGUE OF DRY AND DUSTY AIR CONTINUE TO MOVE WEST.

ATLANTIC OCEAN...

A MIDDLE TO UPPER LEVEL TROUGH ACROSS THE E CONUS AND NW ATLC
WATERS HAS ITS BASE EXTENDING THROUGH THE CENTRAL FLORIDA
PENINSULA. THIS TROUGH SUPPORTS A STATIONARY FRONT N OF THE AREA
OF DISCUSSION...WHICH ASSOCIATED MOISTURE ENHANCES SCATTERED TO
ISOLATED SHOWERS AND TSTMS N OF 29N W OF 77W. SIMILAR CONVECTION
IS BETWEEN ANDROS ISLAND AND CENTRAL CUBA COASTAL WATERS BEING
ENHANCED BY MIDDLE LEVEL DIFFLUENCE. THE REMAINDER BASIN IS
BEING DOMINATED BY BROAD HIGH PRESSURE AND RIDGING ANCHORED BY A
1028 MB HIGH NEAR 34N50W.

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

$$
NR


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