Tropical Weather Discussion
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000
AXNT20 KNHC 190003
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT MON AUG 18 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
2345 UTC.

...TROPICAL WAVES...

A TROPICAL WAVE IS IN THE CENTRAL ATLANTIC WITH AXIS EXTENDING
FROM 19N33W TO 12N34W MOVING W AT 20 KT. SAHARAN DRY AIR IS IN
THE ENVIRONMENT OF THE WAVE WHICH IS HINDERING CONVECTION.

ANOTHER TROPICAL WAVE IS OVER THE CENTRAL TROPICAL ATLANTIC WITH
AXIS EXTENDING FROM 19N43W TO 11N46W...MOVING W AT 15 KT. A
CLUSTER OF MODERATE CONVECTION IS LOCATED SOUTHEAST OF THE WAVE
AXIS FROM 11N-13N BETWEEN 42W-46W COINCIDING WITH A REGION OF
DEEPER MOISTURE AND UPPER LEVEL DIFFLUENCE.

A TROPICAL WAVE IS OVER THE W CARIBBEAN WITH AXIS EXTENDING FROM
22N84W TO 10N86W...MOVING W AT 20-25 KT. MID LEVEL DIFFLUENCE
ALONG WITH MODERATE LOW LEVEL MOISTURE IS ENHANCING ISOLATED
HEAVY SHOWERS AND THUNDERSTORMS NORTH OF 19N BETWEEN 82W-85W.
ALSO...SIMILAR CONVECTION IS OCCURRING IN NICARAGUA AND HONDURAS.

...ITCZ/MONSOON TROUGH...

THE MONSOON TROUGH EXTENDS FROM THE WEST AFRICAN COAST NEAR
15N16W TO A 1010 NM LOW AT 11N21W TO A 1010 MB LOW AT 12N29W TO
12N39W TO 9N53W. THE INTERTROPICAL CONVERGENCE ZONE AXIS BEGINS
NEAR 9N53W TO 8N60W. SCATTERED MODERATE CONVECTION IS FROM
7N-13N E OF 27W AND FROM 7N-13N BETWEEN 30W-40W.

...DISCUSSION...

GULF OF MEXICO...

WEAK SURFACE RIDGING IS CENTERED ACROSS THE NORTHEASTERN GULF OF
MEXICO SUPPORTING 5-15 KT ANTICYLONIC WINDS. THE NORTHERN END OF
A TROPICAL WAVE MOVING ACROSS THE NORTHWESTERN CARIBBEAN WILL
CONTINUE TO PRODUCE SHOWERS AND THUNDERSTORMS ACROSS THE
SOUTHEASTERN GULF...YUCATAN CHANNEL...AND THE YUCATAN PENINSULA
TONIGHT THROUGH TUESDAY. CONVECTION LOCATED OVER THE YUCATAN MAY
SHIFT WEST INTO THE BAY OF CAMPECHE TONIGHT INTO TUESDAY. ACROSS
THE WESTERN GULF...MID LEVEL DIVERGENCE ALONG WITH DEEP LAYER
MODERATE MOISTURE IS ENHANCING SCATTERED MODERATE CONVECTION
WITH ISOLATED TSTMS SOUTH OF 27N WEST OF 93W. THE TROPICAL WAVE
WILL MOVE OUT OF THE SOUTHWEST BASIN BY WEDNESDAY MORNING WITH
SURFACE RIDGING DOMINATING ELSEWHERE.

CARIBBEAN SEA...

A TROPICAL WAVE IS OVER THE W CARIBBEAN ENHANCING ISOLATED HEAVY
SHOWERS AND TSTMS. SEE TROPICAL WAVE SECTION ABOVE. UPPER LEVEL
DIVERGENCE AND THE MONSOON TROUGH ARE SUPPORTING SCATTERED
MODERATE CONVECTION AND ISOLATED TSTMS ACROSS THE EXTREME
SOUTHWESTERN BASIN FROM PANAMA NORTH TO 12N BETWEEN 84W AND 76W.
LOW-LEVEL MOISTURE CONVERGENCE ALONG CUBA IS ENHANCING SCATTERED
HEAVY SHOWERS AND THUNDERSTORMS WHICH EXTEND WITHIN 20 NM OF THE
COASTLINE. ELSEWHERE...FAIR WEATHER DOMINATE BEING SUPPORTED BY
STRONG DEEP LAYER ENVIRONMENTAL SHEAR AND DRY AIR. DUST AND HAZE
IS BEING REPORTED BY MANY OF THE LESSER ANTILLES AS WELL AS
HISPANIOLA ASSOCIATED WITH THE PASSAGE OF A SAHARAN AIRMASS. A
TIGHTER PRESSURE GRADIENT OVER THE CENTRAL AND SW BASIN CONTINUE
TO SUPPORT 20-25 KT WINDS S OF 17N. TRADES OF 10-15 KT DOMINATE
ELSEWHERE. THE TROPICAL WAVE CURRENTLY OVER THE WESTERN BASIN
WILL ENTER THE YUCATAN PENINSULA EARLY MORNING TUESDAY LEAVING
LINGERING SHOWERS OVER THE NW BASIN. THE NEXT TROPICAL WAVE IS
EXPECTED TO ENTER THE EASTERN CARIBBEAN BY THU MORNING.

HISPANIOLA...

DIURNALLY DRIVEN CONVECTION HAS SHIFTED FROM THE MOUNTAINOUS
REGION OF WESTERN DOMINICAN REPUBLIC TO HAITI WHERE SCATTERED
HEAVY SHOWERS AND THUNDERSTORMS ARE NOTED. A SAHARAN AIRMASS IS
ON THE REMAINDER ISLAND WHERE HAZE AND DUST HAVE BEEN REPORTED.
THIS CONVECTION WILL DISSIPATE LATER TONIGHT AS THE SAHARAN
AIRMASS CONTINUES TO MOVE WESTWARD THROUGH TUE NIGHT.

ATLANTIC OCEAN...

A LINE OF SHOWERS AND TSTMS ASSOCIATED WITH THE SEA BREEZE HAS
MOVED INTO THE SW N ATLC WATERS N OF 27N W OF 79W. A PATCH OF
LOW LEVEL MOISTURE ASSOCIATED WITH THE TROPICAL WAVE MOVING ACROSS
THE WESTERN CARIBBEAN ALONG WITH A REGION OF MIDDLE TO UPPER
LEVEL DIFFLUENCE SUPPORT SCATTERED SHOWERS AND ISOLATED TSTMS ON
THE STRAITS OF FLORIDA AND THE CENTRAL BAHAMAS. FARTHER EAST...A
1020 MB HIGH IS ANCHORED NEAR 26N66W WHICH IS FORECAST TO STALL
DURING THE NEXT 24 HOURS. OVER THE CENTRAL ATLC...THERE IS A
WEAKNESS IN THE SURFACE RIDGE BEING REFLECTED AS A 1015 MB LOW
NEAR 30N43W FROM WHICH A SURFACE TROUGH EXTENDS SW TO 24N50W.
THERE IS NO CONVECTION ASSOCIATED WITH THESE TWO FEATURES. EAST
OF THE LOW CENTER...THE TAIL OF A WEAK STATIONARY FRONT IS BEING
ANALYZED FROM 30N32W TO 28N36W WITH NO CONVECTION ASSOCIATED
WITH IT. SURFACE RIDGING AND FAIR WEATHER DOMINATE ELSEWHERE.
OTHERWISE...SEE THE TROPICAL WAVES SECTION ABOVE.

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

$$
NAR/ASL



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