Tropical Weather Discussion
Issued by NWS

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000
AXNT20 KNHC 291719
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT WED JUL 29 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...

A STRONG PRESSURE GRADIENT IS NOTED ACROSS THE CENTRAL CARIBBEAN
SUPPORTING GALE FORCE WINDS FROM 11N-13N BETWEEN 74W-78W. THESE
CONDITIONS ARE FORECAST TO DIMINISH BY 29/1800 UTC AND RE-
INTENSIFY ONCE AGAIN BY 30/0600 UTC. FOR MORE DETAILS PLEASE
REFER TO THE LATEST NWS HIGH SEAS FORECAST UNDER AWIPS/WMO
HEADERS MIAHSFAT2/FZNT02 KNHC.

...TROPICAL WAVES...

A TROPICAL WAVE IS MOVING OVER THE E ATLANTIC WITH AXIS
EXTENDING FROM 19N31W TO 10N30W...MOVING W AT AROUND 15 KT. THE
WAVE COINCIDES WITH 700 MB TROUGHING BETWEEN 25W-35W AND A LOW-
LEVEL MONSOONAL GYRE EMBEDDED WITHIN THE MONSOON TROUGH AXIS
NEAR THE SOUTHERN PORTION OF THE WAVE. ISOLATED MODERATE
CONVECTION IS OBSERVED FROM 09N-11N BETWEEN 29W-31W.

A LOW AMPLITUDE TROPICAL WAVE IS MOVING OVER THE CENTRAL
ATLANTIC WITH AXIS EXTENDING FROM 16N46W TO 10N45W...MOVING W AT
20-25 KT. THE WAVE REMAINS EMBEDDED WITHIN VERY SUBTLE 700 MB
TROUGHING BETWEEN 37W-45W AND MODERATE MOISTURE CONTENT
SURROUNDS THE WAVE. NO SIGNIFICANT CONVECTION IS OCCURRING AT
THIS TIME DUE TO A LARGE AND DRY SAHARAN AIRMASS PREVAILING
ACROSS THE ATLANTIC.

A TROPICAL WAVE IS CURRENTLY OVER THE WINDWARD ISLANDS WITH AXIS
EXTENDING FROM 19N60W TO 11N61W...MOVING W AT 20-25 KT. THE WAVE
COINCIDES WITH BROAD 700 MB TROUGHING BETWEEN 55W-65W. NO
SIGNIFICANT CONVECTION IS OCCURRING WITH THE WAVE AT THIS TIME
DUE TO A LARGE AND DRY SAHARAN AIRMASS PREVAILING ACROSS THE
ATLANTIC.

A TROPICAL WAVE IS MOVING OVER THE W CARIBBEAN WITH AXIS
EXTENDING FROM 20N82W TO 09N82W...MOVING W AT 15-20 KT. THE WAVE
COINCIDES WITH BROAD 700 MB TROUGHING BETWEEN 80W-90W. ISOLATED
MODERATE CONVECTION IS OBSERVED ALONG THE SOUTHERN PORTION OF
THE WAVE...MAINLY S OF 12N.

...ITCZ/MONSOON TROUGH...

THE MONSOON TROUGH AXIS EXTENDS FROM THE AFRICAN COAST NEAR
19N16W TO A 1010 MB LOW NEAR 12N21W TO 11N29W...THEN RESUMES W
OF A TROPICAL WAVE NEAR 10N31W TO 10N38W. THE INTERTROPICAL
CONVERGENCE ZONE AXIS EXTENDS FROM 10N38W TO 12N44W...THEN
RESUMES W OF A TROPICAL WAVE NEAR 11N48W TO 10N59W. SCATTERED
MODERATE CONVECTION IS OBSERVED SURROUNDING THE SURFACE LOW FROM
09N-14N BETWEEN 19W-28W.

...DISCUSSION...

GULF OF MEXICO...

A NE TO E FLOW ALOFT PREVAILS ACROSS THE BASIN ON THE SOUTHERN
PERIPHERY OF AN UPPER-LEVEL HIGH CENTERED OVER NE TEXAS. WATER
VAPOR IMAGERY INDICATES MOST ATMOSPHERIC MOISTURE IS NOTED
ACROSS THE EASTERN HALF OF THE GULF MAINLY E OF 90W. A SURFACE
TROUGH EXTENDS ACROSS THE FLORIDA PENINSULA FROM A 1012 MB LOW
CENTERED OVER THE W ATLANTIC ENHANCING SCATTERED MODERATE
CONVECTION FROM 25N-27N AND BETWEEN 82W-89W. A SURFACE RIDGE
ANCHORED BY A 1017 MB HIGH CENTERED NEAR 24N86W IS PROVIDING THE
BASIN WITH GENTLE TO MODERATE ANTICYCLONIC BREEZE CONDITIONS.
OVER THE NEXT 24 HOURS...THE SURFACE HIGH WILL PREVAIL ACROSS
THE BASIN DRIFTING NW. BY THE WEEKEND...A WEAK FRONTAL TROUGHING
IS EXPECTED TO EXTEND ALONG THE NORTHERN GULF WATERS.

CARIBBEAN SEA...

A TROPICAL WAVE IS OVER THE W CARIBBEAN. PLEASE REFER TO THE
SECTION ABOVE FOR MORE DETAILS. FAIR WEATHER PREVAILS ACROSS
MOST OF THE BASIN AS A BROAD SAHARAN AIRMASS DOMINATES THE AREA.
SCATTEROMETER DATA DEPICTS GENTLE TO MODERATE TRADES ACROSS MOST
OF THE BASIN EXCEPT S OF 14N BETWEEN 74W-78W WHERE STRONG TO
GALE FORCE WINDS PREVAIL. PLEASE REFER TO THE SPECIAL FEATURES
SECTION FOR MORE DETAILS. SIMILAR WEATHER CONDITIONS WILL ARE
EXPECTED OVER THE NEXT 24 HOURS.

...HISPANIOLA...

MOSTLY CLEAR SKIES AND FAIR WEATHER PREVAIL ACROSS THE ISLAND AS
A SAHARAN AIRMASS DOMINATES THE CARIBBEAN. THIS PATTERN WILL
PREVAIL OVER THE NEXT 24 HOURS.

ATLANTIC OCEAN...

AN UPPER-LEVEL TROUGH IS NOTED ON WATER VAPOR IMAGERY OVER THE W
ATLANTIC SUPPORTING A PAIR OF SURFACE LOWS...ONE CENTERED NEAR
31N79W AND THE OTHER NEAR 33N75W. A SURFACE TROUGH EXTENDS FROM
THE FLORIDA PENINSULA INTO THE W ATLANTIC CONNECTED TO THE LOW
ALONG 79W AND SUPPORTING SCATTERED MODERATE CONVECTION FROM 27N-
30N BETWEEN 76W-80W. A FRONTAL SYSTEM PREVAILS N OF 31N
CONTINUES TO ENHANCE ISOLATED CONVECTION MAINLY N OF 29N BETWEEN
68W-73W. A SURFACE RIDGE PREVAILS ACROSS THE REMAINDER OF THE
BASIN ANCHORED BY A 1020 MB SURFACE HIGH NEAR 28N67W AND A 1026
MB SURFACE HIGH NEAR 35N31W.

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

$$

ERA



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