Tropical Weather Discussion
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000
AXNT20 KNHC 111033
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 AM EDT FRI JUL 11 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1030 UTC.

...TROPICAL WAVES...
TROPICAL WAVE IS WEST OF THE CAPE VERDE ISLANDS WITH AXIS
EXTENDING FROM 22N26W TO 9N31W MOVING W AT 15 KT. THE WAVE
CONTINUES EMBEDDED IN THE DRY SAHARAN AIR LAYER...THEREFORE NO
CONVECTION IS ASSOCIATED WITH IT.

TROPICAL WAVE IS OVER THE EASTERN CARIBBEAN WITH AXIS EXTENDING
FROM 19N62W TO 10N66W MOVING W AT 20-25 KT. DEEP LAYER MOISTURE
IS ASSOCIATED WITH THE WAVE WHICH IS ENHANCING SCATTERED SHOWERS
E-SE OF A LINE FROM 18N64W TO 11N70W.

TROPICAL WAVE IS LOCATED OVER THE CENTRAL CARIBBEAN WITH AXIS
EXTENDING FROM 20N73W TO 10N75W MOVING W AT 20 KT. DRY AIR FROM
A SAHARAN AIRMASS IS MOVING ACROSS THE CENTRAL WAVE ENVIRONMENT
WHICH ALONG STRONG DEEP LAYER ENVIRONMENTAL SHEAR IN THE
CARIBBEAN HINDER CONVECTION AT THE TIME. HOWEVER...LIFTING OF
MOIST AIR IS BEING SUPPORTED BY AN UPPER-LEVEL LOW CENTERED IN
THE WINDWARD PASSAGE...THUS ENHANCING SHOWERS AND TSTMS AHEAD OF
THE AXIS FROM 18N-20N BETWEEN 73W-77W.

...ITCZ/MONSOON TROUGH...
THE MONSOON TROUGH EXTENDS FROM THE WEST AFRICAN COAST NEAR
13N16W TO 10N22W. THE INTERTROPICAL CONVERGENCE ZONE AXIS BEGINS
NEAR 10N22W AND CONTINUES ALONG 7N37W TO THE SOUTH AMERICAN
COAST NEAR 5N53W. IN ADDITION TO THE CONVECTION ASSOCIATED WITH
THE TROPICAL WAVE...SCATTERED MODERATE CONVECTION IS LOCATED
FROM 8N-12N BETWEEN 21W-29W...FROM 5N-10N BETWEEN 34W-39W AND
FROM 5N-9N W OF 51W.

...DISCUSSION...

GULF OF MEXICO...
THE NORTH ATLC SUBTROPICAL HIGH CONTINUES TO EXTEND A RIDGE AXIS
SW INTO THE GULF THUS SUSTAINING HIGH PRESSURE ACROSS THE ENTIRE
BASIN. THE SURFACE RIDGE IN THE GULF IS BEING ANCHORED BY A 1019
MB HIGH OVER THE NE WATERS NEAR 28N87W AND PROVIDES E-SE WIND
FLOW OF 5-20 KT ACROSS MUCH OF THE GULF...BEING THE STRONGEST
WINDS AT THE BAY OF CAMPECHE. EXCEPT FOR THE W-NW GULF AT THE
LOWER-LEVELS...DEEP LAYER MOIST AIR IS PRESENT ACROSS THE
REMAINDER BASIN. IN THE W GULF...BOTH DRY AIR AND DEEP LAYER
STRONG ENVIRONMENTAL WIND SHEAR INHIBIT CONVECTION. THE SW AND E
BASIN ARE ALSO DEVOID OF CONVECTION AS ENVIRONMENTAL CONDITIONS
ARE NOT FAVORING AIR LIFTING. THE CENTER OF HIGH PRESSURE IS
FORECAST TO PERSIST ACROSS THE N-NE GULF THROUGH SUN NIGHT.

CARIBBEAN SEA...
THE NORTH ATLC SUBTROPICAL HIGH CONTINUES TO EXTEND A RIDGE AXIS
SW INTO THE NORTHERN CARIBBEAN WATERS. THIS CONTINUES TO SUPPORT
A TIGHT PRESSURE GRADIENT IN THE CENTRAL AND EASTERN
BASIN...THUS SUPPORTING A MODERATE TO FRESH BREEZE BETWEEN 64W-
80W. EXCEPT FOR PORTIONS OF THE NORTH CENTRAL BASIN WHERE DRY
AIR FROM A SAHARAN AIRMASS LINGERS...THE REMAINDER BASIN SHOW A
MOISTURE INCREASE. HOWEVER...STRONG DEEP LAYER ENVIRONMENTAL
SHEAR OVER THE THE SW AND CENTRAL BASIN HINDERS THE DEVELOPMENT
OF CONVECTION AT THE TIME. TWO TROPICAL WAVES ARE MOVING ACROSS
THE CARIBBEAN. SEE THE TROPICAL WAVES SECTION ABOVE FOR DETAILS.
OTHERWISE...AN UPPER-LEVEL CYCLONIC CIRCULATION CENTERED OVER
THE WINDWARD PASSAGE SUPPORT SHOWERS AND TSTMS BETWEEN
CUBA...JAMAICA AND HISPANIOLA FROM 18N-21N BETWEEN 74W-77W.
SIMILAR CONVECTION IS OVER COASTAL WATERS OF SE CUBA.

...HISPANIOLA...
A BROAD UPPER-LEVEL CYCLONIC CIRCULATION CENTERED OVER THE
WINDWARD PASSAGE EXTENDS A TROUGH TO NORTHERN COLOMBIA. THIS IS
SUPPORTING ISOLATED SHOWERS/TSTMS OVER THE WINDWARD PASSAGE AS
WELL AS HAITI COASTAL WATERS. SHOWERS ARE EXPECTED TO CONTINUE
THROUGH SAT MORNING AS THE UPPER LOW MOVES SLOWLY NW TO EASTERN
CUBA.

ATLANTIC OCEAN...
NO SIGNIFICANT WEATHER HAPPENING IN THE BASIN. THIS IS DUE TO
THE PRESENCE OF VERY DRY AIR ACROSS THE CENTRAL AND EASTERN ATLC
AS WELL AS THE NORTH ATLC SUBTROPICAL HIGH. OVER THE TROPICAL
ATLC...A WAVE IS WEST OF THE CAPE VERDE ISLANDS WITH NO
CONVECTION ASSOCIATED WITH IT. SEE THE TROPICAL SECTION ABOVE FOR
MORE MORE INFORMATION. OTHERWISE...BESIDES A SURFACE TROUGH FOR
THE SW N ATLC...NO SIGNIFICANT CHANGES ARE EXPECTED DURING THE
NEXT COUPLE OF DAYS.

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

$$
NR



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