[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 050557
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
205 AM EDT MON AUG 05 2013

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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
0522 UTC.

...TROPICAL WAVES...
A TROPICAL WAVE AXIS EXTENDS FROM 26N44W TO 15N41W MOVING W-NW
NEAR 5 KT. THE METEOSAT-9 SAL TRACKING PRODUCT CONTINUES TO SHOW
DRY AIR SPREADING OVER THE WAVE ENVIRONMENT WHICH IS HINDERING
CONVECTION.

...THE ITCZ/THE MONSOON TROUGH...
THE MONSOON TROUGH AXIS EXTENDS FROM THE AFRICAN COAST NEAR
13N16W TO 10N24W 10N30W. THE INTERTROPICAL CONVERGENCE ZONE AXIS
STARTS NEAR 10N30W AND CONTINUES ALONG 10N40W TO 07N50W.
SCATTERED MODERATE CONVECTION IS FROM 08N-12N BETWEEN 16W-
31W...FROM 06N-12N BETWEEN 36W-45W AS WELL AS FROM 05N-09N
BETWEEN 49W-54W.

...DISCUSSION...

THE GULF OF MEXICO...
AS OF 0300 UTC...THE AZORES HIGH EXTENDS A RIDGE AXIS INTO THE
GULF. ANTICYCLONIC FLOW IN THE RANGE OF 5-15 KT SPREADS ACROSS
THE BASIN ANCHORED BY A 1019 MB HIGH NEAR 26N89W BEING SUPPORTED
BY A BROAD MIDDLE TO UPPER LEVEL RIDGE. DRY AIR IN THE LOWER AND
MIDDLE LEVELS IS SUPPORTING FAIR WEATHER OVER THE WESTERN GULF.
A HIGH MOIST ENVIRONMENT IS OVER THE NE GULF WHERE SCATTERED
MODERATE CONVECTION AND ISOLATED TSTMS ASSOCIATED TO A COLD
FRONT UP NORTH ARE N OF 28N E OF 90W. SCATTERED MODERATE
CONVECTION IS ALSO IN THE BAY OF CAMPECHE S OF 20N E OF 93W.

THE CENTER OF HIGH PRESSURE IS EXPECTED TO PERSIST DURING THE
NEXT 48 HOURS. RAINSHOWERS IN THE NE GULF ASSOCIATED WITH THE
FRONTAL SYSTEM UP NORTH ARE LIKELY TO CONTINUE. RAINSHOWERS ARE
ALSO EXPECTED IN THE BAY OF CAMPECHE AS A SURFACE TROUGH MOVES
IN THE AREA.

THE CARIBBEAN SEA...
EXCEPT FOR THE FAR WESTERN CARIBBEAN...THE WINDWARD PASSAGE AND
THE SOUTHERN CARIBBEAN...VERY DRY AIR FROM A SAHARAN OUTBREAK
SPREADS ACROSS THE BASIN IN THE LOWER AND MIDDLE LEVELS WHICH IS
FAVORING FAIR WEATHER. SURFACE RIDGING IS ACROSS THE CARIBBEAN
WITH TRADEWINDS RANGING FROM 20-25 KT OVER THE CENTRAL-SOUTHERN
BASIN AND 5-15 KT ELSEWHERE. SCATTERED MODERATE CONVECTION AND
ISOLATED TSTMS ARE WITHIN 200 NM OF THE COAST OF NICARAGUA BEING
SUPPORTED BY HIGH LOW LEVEL MOISTURE AND UPPER LEVEL DIVERGENCE.
SIMILAR CONVECTION IS WITHIN 100 NM OF THE COAST OF COSTA RICA
AND ASSOCIATED WITH THE MONSOON TROUGH AXIS. UPPER LEVEL
DIFFLUENCE IS SUPPORTING ISOLATED SHOWERS AND TSTMS OVER THE
WESTERN CARIBBEAN S OF 19N W OF 84W. SCATTERED MODERATE
CONVECTION AND TSTMS ARE BETWEEN JAMAICA AND THE HISPANIOLA N OF
17N BEING SUPPORTED BY UPPER LEVEL DIFFLUENCE FROM A BROAD RIDGE
CENTERED OVER SOUTHERN U.S.A. AND A LOW CENTERED NE OF
HISPANIOLA.

DRY AIR IS EXPECTED TO PERSIST OVER MOST OF THE BASIN WITHIN THE
NEXT 48 HOURS SUPPORTING FAIR WEATHER. A NEW TROPICAL WAVE IS
LIKELY TO ENTER THE EASTERN CARIBBEAN TUESDAY.

HISPANIOLA...
EXCEPT FOR SOUTHERN HAITI...CURRENTLY VERY DRY AIR IS ACROSS THE
ISLAND SUPPORTING FAIR WEATHER. OVER THE WINDWARD PASSAGE
MODERATE MOIST AIR AND UPPER LEVEL DIFFLUENCE ARE SUPPORTING
MODERATE CONVECTION AND TSTMS BETWEEN JAMAICA AND THE HISPANIOLA
N OF 17N. A DRY AIRMASS WILL BE MOVING ACROSS THE ISLAND LATER
TODAY AND TUESDAY MORNING SUPPORTING FAIR WEATHER. SHOWERS AND
TSTMS ARE EXPECTED TUESDAY AFTERNOON/EARLY EVENING ASSOCIATED
WITH DAYTIME HEATING.

THE ATLANTIC OCEAN...
BESIDES THE TROPICAL WAVE ALREADY DISCUSSED...A PREFRONTAL
TROUGH ENTERS THE AREA OF DISCUSSION IN THE W ATLC NEAR 30N71W
TO 26N76W. SCATTERED MODERATE CONVECTION AND TSTMS ARE WITHIN
180 NM W OF THE TROUGH AXIS N OF 29N. ISOLATED SHOWERS
ASSOCIATED WITH THE FRONTAL SYSTEM N OF THE AREA ARE N OF 28N W
OF 77W. ANOTHER SURFACE TROUGH IS AHEAD THE TROPICAL WAVE
EXTENDING FROM 27N50W TO 21N51W WITH NO CONVECTION ASSOCIATED
WITH IT. OTHERWISE...SURFACE RIDGING AND FAIR WEATHER SUPPORTED
BY LOWER-MIDDLE LEVEL DRY AIR ARE ACROSS THE REMAINDER BASIN.

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

$$
NR


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