[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 230005
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT FRI AUG 22 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
2315 UTC.

...SPECIAL FEATURES...

A 1007 MB LOW IS LOCATED 130 NM MILES EAST OF THE NORTHERN COAST
OF HISPANIOLA NEAR 19N68W...MOVING WNW AT 15-20 KT. A TROPICAL
WAVE EXTENDS N FROM THE LOW CENTER TO 26N68W. A BAND OF NUMEROUS
MODERATE TO STRONG CONVECTION IS LOCATED TO THE WEST OF THE LOW
CENTER FROM 18N-24N BETWEEN 68W-72W. SAN JUAN RADAR IS SHOWING A
LARGE AREA OF HEAVY PRECIPITATION EXTENDING OVER 100 MILES SOUTH
OF PUERTO RICO WITH OTHER CLUSTERS OF HEAVY RAINFALL BETWEEN
PUERTO RICO AND HISPANIOLA. OTHER BANDS OF SCATTERED TO NUMEROUS
SHOWERS AND THUNDERSTORMS ARE INDICATED ON RADAR TO THE SOUTH
AND EAST OF PUERTO RICO. SCATTERED MODERATE CONVECTION IS
LOCATED ON THE WESTERN SEMI-CIRCLE OF THE LOW FROM 15-23N
BETWEEN 68W-64W. THIS LOW HAS BEEN BECOMING BETTER ORGANIZED
THIS AFTERNOON WITH SHOWERS AND THUNDERSTORMS INCREASING
THROUGHOUT TODAY. GUSTY WINDS AND HEAVY RAIN ARE EXPECTED ACROSS
PUERTO RICO...HISPANIOLA...THE BAHAMAS...AND THE OPEN WATERS
BETWEEN THESE ISLANDS TONIGHT THROUGH SATURDAY.

GRADUAL DEVELOPMENT OF THE LOW IS EXPECTED DURING THE NEXT FEW
DAYS AS IT MOVES ALONG OR NORTH OF THE GREATER ANTILLES.
INTERESTS DOWNSTREAM OF THE LOW SHOULD MONITOR CLOSELY THE
PROGRESS OF THIS SYSTEM. CHANCES FOR DEVELOPMENT INTO A TROPICAL
CYCLONE DURING THE NEXT 48 HOURS IS HIGH.

...TROPICAL WAVES...

A TROPICAL WAVE IS WEST OF THE CAPE VERDE ISLANDS WITH AXIS
EXTENDING FROM 10N32W TO 27N32W MOVING W AT 5-10 KT. NO
SIGNIFICANT CONVECTION IS OCCURRING AT THIS TIME AS DRY
SAHARAN AIR AND DUST ARE IN ITS ENVIRONMENT.

A TROPICAL WAVE IS EAST OF THE LEEWARD ISLANDS WITH AXIS
EXTENDING FROM 26N68W TO THE CENTER OF A LOW PRESSURE SYSTEM
NEAR 19N68W. SEE SPECIAL FEATURES SECTION FOR MORE INFORMATION.

...ITCZ/MONSOON TROUGH...

THE MONSOON TROUGH EXTENDS FROM THE AFRICAN COAST NEAR 14N17W
AND CONTINUES ALONG 10N27W TO 9N33W TO 08N39W. AN ITCZ EXTENDS
FROM 08N39W TO 08N54W. SCATTERED MODERATE CONVECTION IS FROM 07N-
14N E OF 24W AND WIDELY SCATTERED SHOWERS AND THUNDERSTORMS ARE
FROM 06N-10N BETWEEN 28W-55W.

...DISCUSSION...

GULF OF MEXICO...

A 1020 MB HIGH PRESSURE SYSTEM IS CENTERED ON THE N GULF NEAR
29N91W. SURFACE OBS AND SCATTEREOMETER WINDS SHOW ANTICYCLONIC
WINDS MAINLY BETWEEN 5-10 KT WITH 15 KT EVIDENT ACROSS THE
SOUTHWESTERN GULF. UPPER LEVEL DIFFLUENCE AND LOW LEVEL MOISTURE
IS SUPPORTING SCATTERED SHOWERS AND THUNDERSTORMS ACROSS THE W
CENTRAL GULF. LOW LEVEL MOISTURE IS SUPPORTING ISOLATED SHOWERS
AND THUNDERSTORMS OVER THE SOUTHEASTERN GULF. EXPECT SCATTERED
SHOWERS AND THUNDERSTORMS ARE FORECAST MAINLY ACROSS THE WESTERN
HALF OF THE BASIN OVER THE NEXT 24 HOURS.

CARIBBEAN SEA...

AN AREA OF LOW PRESSURE ASSOCIATED WITH A TROPICAL WAVE IS NE OF
HISPANIOLA...WITH LOW PRESSURE CENTER LOCATED NEAR 19N68W. LOW
LEVEL CONVERGENCE...UPPER LEVEL DIFFLUENCE...AND DEEP LAYER
MOISTURE ASSOCIATED WITH THIS SYSTEM ARE SUPPORTING THE
CONVECTION DESCRIBED IN THE SPECIAL FEATURES SECTION.

AN ELONGATED UPPER LEVEL LOW EXTENDS ACROSS THE WESTERN
CARIBBEAN. THIS LOW ACCOMPANIED BY UPPER LEVEL DIFFLUENCE ACROSS
THE NW BASIN IS ENHANCING SHOWERS AND THUNDERSTORMS ON WESTERN
CUBA AND THE ADJACENT WATERS. THE REMAINDER OF THE BASIN IS
CONVECTION FREE IN THE PRESENCE OF DRY AIR. TRADE WINDS OF 10-15
KT ARE MAINLY ACROSS THE WESTERN PART OF THE BASIN WITH WINDS UP
TO 20 KT NEAR THE NORTH OF THE COLOMBIAN COAST. WINDS EAST OF
67W BECOME SOUTH TO SOUTHEASTERLY OF 15-25 KT IN THE LOW LEVEL
FLOW TO THE SOUTHEAST OF THE LOW IN THE SPECIAL FEATURES
SECTION. SHOWERS...THUNDERSTORMS...AND GUSTY WINDS ASSOCIATED
WITH THIS LOW WILL AFFECT THE GREATER ANTILLES AND OFFSHORE
WATERS TO THE SOUTH OF HISPANIOLA AND CUBA OVER THE WEEKEND.

...HISPANIOLA...

MOISTURE AND CONVECTION IS INCREASING AS THE LOW PRESSURE
DISCUSSED IN THE SPECIAL FEATURES SECTION APPROACHES THE ISLAND.
NUMEROUS SHOWERS AND THUNDERSTORMS WITH POSSIBLE LOCALIZED
FLOODING AND GUSTY WINDS ARE EXPECTED OVER THE WEEKEND...PEAKING
BY SATURDAY MORNING AS THE SYSTEM TRACKS TO THE NORTH OF THE THE
ISLAND.

ATLANTIC OCEAN...

A MID/UPPER LEVEL ANTICYCLONE IS CENTERED JUST E OF NE FLORIDA
WITH ITS ASSOCIATED BROAD MID/UPPER LEVEL ANTICYCLONIC FLOW
COVERING THE NW PORTION TO THE NW OF A LINE FROM 32N70W TO
26N75W TO WESTERN CUBA. AN INVERTED MID LEVEL TROUGH IS NOTED TO
THE SE OF THIS ANTICYCLONIC FLOW ALONG A POSITION FROM 27N73W TO
25N75W TO 22N79W. AN UPPER TROUGH CONTINUES NEWD FROM 27N73W TO
NE OF THE AREA AT 32N59W. MOIST LOW LEVEL NE FLOW UNDER THE
ANTICYCLONIC FLOW OVER THE NW PORTION IS BRINGING WIDELY
SCATTERED SHOWERS AND ISOLATED SHOWERS AND TSTMS ACROSS MUCH OF
THE BAHAMAS AND WATERS BETWEEN THE BAHAMAS AND THE FLORIDA KEYS
INCLUDING THE STRAITS OF FLORIDA. STRONG CONVECTION AND GUSTY
WINDS ARE LOCATED NORTH OF THE LEEWARD ISLANDS AND GREATER
ANTILLES ASSOCIATED WITH THE SYSTEM IN THE SPECIAL FEATURES.
FOR MORE INFORMATION...SEE ABOVE.

ANOTHER MID/UPPER LEVEL ANTICYCLONE IS LOCATED TO THE E OF
SPECIAL FEATURES LOW NEAR 22N63W. BROAD ANTICYCLONIC ASSOCIATED
WITH THIS FEATURE COVERS THE AREA BETWEEN INVERTED TROUGH AND
56W. E OF THIS FEATURE THE ATMOSPHERE REMAINS DRY AND STABLE
UNDER MODERATE SUBSIDENCE. AT THE SURFACE...RATHER WEAK SURFACE
RIDGING PREVAILS. ELSEWHERE E OF THE STRONG CONVECTION
ASSOCIATED WITH THE LOW...ONLY ISOLATED SHOWERS POSSIBLE
THROUGHOUT E OF THE SPECIAL FEATURES LOW.

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

$$
LATTO/AGUIRRE


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