Tropical Weather Discussion
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000
AXNT20 KNHC 151800
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT FRI AUG 15 2014

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.

...TROPICAL WAVES...

A TROPICAL WAVE IS EAST OF THE CAPE VERDE ISLANDS WITH AXIS
EXTENDING FROM 19N19W TO 10N20W...MOVING W AT 5-10 KT. THE
SOUTHERN PORTION OF THE WAVE CONTINUES EMBEDDED IN THE MONSOON
TROUGH WHERE DEEP LAYER MOISTURE AND MIDDLE TO UPPER LEVEL
DIFFLUENCE SUPPORT SCATTERED MODERATE CONVECTION FROM 7N-14N
BETWEEN 17W-24W.

A TROPICAL WAVE IS ON THE CENTRAL ATLC WITH AXIS EXTENDING FROM
17N31W TO A 1012 MB LOW NEAR 11N31W TO 7N31W...MOVING W AT 10
KT. METEOSAT PSEUDO NATURAL AND SAL TRACKING IMAGERY INDICATE
SAHARAN DUST AND DRY AIR IN THE WAVE ENVIRONMENT N OF THE LOW
CENTER...WHICH IS SUPPRESSING CONVECTION IN THE NORTHERN AND
CENTRAL PORTIONS OF THE WAVE. SCATTERED MODERATE CONVECTION IS
MOSTLY LIMITED S OF THE MONSOON TROUGH FROM 5N-10N BETWEEN 29W-
39W.

A TROPICAL WAVE IS ABOUT 90 NM E OF THE LESSER ANTILLES WITH
AXIS EXTENDING FROM 19N55W TO 10N57W...MOVING W AT 20 KT. MOSTLY
MODERATE DEEP LAYER MOISTURE IS ASSOCIATED WITH THIS WAVE WHICH
ALONG MIDDLE TO UPPER LEVEL DIFFLUENCE SUPPORT SCATTERED
MODERATE CONVECTION AND ISOLATED TSTMS WITHIN 210 NM WEST OF ITS
AXIS.

A TROPICAL WAVE IS MOVING ACROSS SOUTHERN MEXICO AND E PAC
WATERS WITH AXIS EXTENDING FROM THE BAY OF CAMPECHE NEAR 20N94W
TO 10N97W...MOVING W AT 20 KT. ISOLATED SHOWERS AND TSTMS ARE ON
THE SW GULF S OF 20N W OF 93W.

...ITCZ/MONSOON TROUGH...

THE MONSOON TROUGH EXTENDS FROM THE WEST AFRICAN COAST NEAR
14N17W AND THEN CONTINUES ALONG 11N25W TO 1 1012 MB LOW NEAR
11N31W TO 8N43W. THE INTERTROPICAL CONVERGENCE ZONE AXIS BEGINS
NEAR 8N43W AND CONTINUES TO 11N53W. FOR INFORMATION REGARDING
CONVECTION SEE THE TROPICAL WAVES SECTION.

...DISCUSSION...

GULF OF MEXICO...

A BROAD UPPER-LEVEL TROUGH CONTINUES ACROSS THE EASTERN CONUS
WITH BASE EXTENDING SW INTO THE CENTRAL AND SW GULF. THIS TROUGH
ALOFT SUPPORTS A STATIONARY FRONT ANALYZED FROM 30N85W SW TO
29N90W TO SE TEXAS NEAR 29N94W. A TROPICAL WAVE IS MOVING ACROSS
SOUTHERN MEXICO AND THE E PAC WATERS. THIS WAVE IS ENHANCING
ISOLATED SHOWERS AND TSTMS ON THE BAY OF CAMPECHE S OF 20N W OF
93W. OTHERWISE...A WEAK SURFACE RIDGE DOMINATES THE REMAINDER
BASIN WHICH IS PROVIDING THE BASIN WITH VARIABLE WINDS OF 5-10
KT. RETURN FLOW ASSOCIATED WITH THIS RIDGE HAS BEEN ADVECTING
MODERATE TO HIGH LOW-LEVEL MOISTURE FROM THE CARIBBEAN INTO THE
BASIN WHICH IS FUELING HEAVY SHOWERS AND TSTMS FROM 25N-28N
BETWEEN 89W-92W AS WELL AS N OF 26N E OF 87W...INCLUDING THE
FLORIDA PENINSULA. ISOLATED SHOWERS ARE ELSEWHERE N OF 22N E OF
96W. SURFACE RIDGING WILL DOMINATE ACROSS THE BASIN DURING THE
WEEKEND.

CARIBBEAN SEA...

A MIDDLE-LEVEL INVERTED TROUGH IS ON THE NW CARIBBEAN WHICH
SUPPORT A SURFACE TROUGH FROM 19N80W TO 16N83W THAT ENHANCES
SCATTERED SHOWERS AND TSTMS FROM 15N-19N BETWEEN 80W-84W.
MODERATE DEEP LAYER MOISTURE ON THE SW CARIBBEAN ALONG WITH
UPPER-LEVEL DIFFLUENCE SUPPORT A CLUSTER OF HEAVY SHOWERS AND
TSTMS S OF 11N W OF 80W. DEEP LAYER DRY AIR IS ACROSS THE
REMAINDER BASIN...THUS SUPPORTING FAIR WEATHER.
HOWEVER...HAZINESS IS POSSIBLE OVER PORTIONS OF THE CENTRAL AND
EASTERN CARIBBEAN AS THE SAHARAN DRY AIRMASS CONTINUES TO MOVE
ACROSS THIS REGION DURING THE WEEKEND. A RELATIVE TIGHT PRESSURE
GRADIENT ACROSS THE CENTRAL AND SW CARIBBEAN SUPPORT TRADES OF
20-25 KT IN THIS REGION. ELSEWHERE...TRADES OF 5-15 KT DOMINATE.
A TROPICAL WAVE IS FORECAST TO ENTER THE E BASIN EARLY SATURDAY
MORNING AND IS EXPECTED TO MOVE ACROSS HISPANIOLA SUN MORNING.

HISPANIOLA...

DEEP LAYER DRY AIR CONTINUES ACROSS THE ISLAND WHICH IS
PROVIDING AN OVERALL STABLE ENVIRONMENT. THE DRY SAHARAN AIRMASS
WILL CONTINUE TO MOVE ACROSS THE ISLAND THROUGH SATURDAY
AFTERNOON THUS SUPPORTING FAIR WEATHER BUT SOME HAZINESS. ON
SUNDAY...THE PASSAGE OF A TROPICAL WAVE ACROSS THE ISLAND WILL
ENHANCE RAINSHOWERS.

ATLANTIC OCEAN...

ABUNDANT MOISTURE FROM THE GULF IS BEING ADVECTED BY SW FLOW
ACROSS THE SW N ATLC WATERS WHICH ALONG MIDDLE TO UPPER LEVEL
DIFFLUENCE SUPPORT HEAVY SHOWERS AND TSTMS N OF 24N W OF 70W.
OTHERWISE...THE CENTRAL AND EASTERN ATLC CONTINUE UNDER THE
INFLUENCE OF A SURFACE RIDGE ANCHORED BY A 1021 MB HIGH CENTERED
NEAR 25N59W AND A 1028 MB HIGH NE OF THE AZORES ISLANDS.

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

$$
NR


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