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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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