[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 040544
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
205 AM EDT SUN AUG 04 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
0515 UTC.

...TROPICAL WAVES...
TROPICAL WAVE EXTENDS FROM 09N35W TO 19N34W MOVING W AT 10-15
KT. THE WAVE REMAINS EMBEDDED WITHIN THE MONSOON TROUGH AXIS
WITH A MID-LATITUDE SURFACE TROUGH ANALYZED TO THE NW OF THE
WAVE FROM 18N40W TO 25N39W. WHILE NEITHER FEATURE EXHIBITS A
STRONG SIGNAL ON SATELLITE IMAGERY AND IN GLOBAL MODEL
DATA...ENERGY ASSOCIATED WITH EACH ARE FORECAST TO MERGE WITHIN
THE NEXT 12 TO 24 HOURS ACROSS THE CENTRAL ATLC AND CONTINUE A
WESTWARD MOVEMENT TOWARD THE LESSER ANTILLES REACHING 60W BY
MONDAY. THE WAVE IS SURROUNDED BY A LARGE AREA OF SUSPENDED
SAHARAN DUST AT THIS TIME WITH NO CONVECTION OCCURRING IN THE
VICINITY OF THE WAVE.

...ITCZ/MONSOON TROUGH...
THE MONSOON TROUGH AXIS EXTENDS FROM THE AFRICAN COAST NEAR
13N17W TO 13N26W TO 08N40W TO 06N50W. THE INTERTROPICAL
CONVERGENCE ZONE AXIS EXTENDS FROM 06N50W TO 06N53W. SCATTERED
MODERATE CONVECTION IS FROM 10N-14N BETWEEN 18W-30W...AND FROM
05N-09N BETWEEN 33W-46W.

...DISCUSSION...

GULF OF MEXICO...
A MIDDLE TO UPPER LEVEL ANTICYCLONIC CIRCULATION IS CENTERED
OVER NORTH TEXAS NEAR 32N98W AND IS PROVIDING THE GULF WITH
NORTHEAST TO EASTERLY FLOW ALOFT. WATER VAPOR IMAGERY INDICATES
IT REMAINS MODERATELY DRY AND STABLE WITH UPPER LEVEL CONVECTIVE
DEBRIS CLOUDINESS COVERING THE NORTHERN GULF N OF 25N THIS
EVENING. OTHERWISE AS OF 04/0300 UTC...THE GULF IS UNDER THE
INFLUENCE OF A SURFACE RIDGE ANCHORED BY A 1021 MB HIGH CENTERED
OVER THE EASTERN GULF NEAR 25N84W. A FEW ISOLATED SHOWERS AND
TSTMS ARE OCCURRING S OF 21N OVER THE SW GULF. LOOKING AHEAD...
RIDGING WILL DOMINATE OVER THE BASIN THROUGH WEDNESDAY WITH
SOUTHERLY WINDS PREVAILING W OF 90W IN THE RANGE OF 10-20 KT.

CARIBBEAN SEA...
AN UPPER LEVEL ANTICYCLONIC CIRCULATION IS CENTERED OVER THE
WESTERN CARIBBEAN NEAR 14N81W THAT IS ADVECTING MOISTURE
NORTHWARD ON THE WESTERN PERHIPHERY OF THE RIDGING ACROSS
PORTIONS OF CENTRAL AMERICA PRODUCING SCATTERED SHOWERS AND
ISOLATED TSTMS S OF 19N W OF 82W. FARTHER SOUTH ACROSS SOUTHERN
NICARAGUA...COSTA RICA...AND PANAMA...SCATTERED SHOWERS AND
TSTMS ARE OCCURRING DUE TO MAXIMUM UPPER LEVEL DIFFLUENCE AND
ALSO THE PRESENCE OF THE MONSOON TROUGH AXIS ANALYZED ALONG
09N/10N FROM NORTHERN COLOMBIA TO SOUTHERN COSTA RICA AND INTO
THE EAST PACIFIC REGION. ON THE EASTERN PERIPHERY OF THE UPPER
LEVEL ANTICYCLONE...A DRIER NORTHWESTERLY FLOW PREVAILS BETWEEN
70W-80W WITH MOSTLY CLEAR SKIES AND FAIR CONDITIONS. FINALLY...
OVER THE EASTERN CARIBBEAN AN UPPER LEVEL LOW IS CENTERED NORTH
OF PUERTO RICO NEAR 23N65W PROVIDING TROUGHING E OF 70W. WATER
VAPOR IMAGERY INDICATES THE TROUGHING EXHIBITS RELATIVELY DRY
AIR ALOFT AND THIS IS RESULTING IN ONLY A FEW ISOLATED LOW-
TOPPED SHOWERS OCCURRING N OF 16N BETWEEN 67W-72W...AND E OF
64W...INCLUDING THE LESSER ANTILLES. OTHERWISE...THE SAHARAN AIR
LAYER CONTINUES TO PROVIDE A LARGE INFLUENCE TO THE OVERALL
STABILITY OF THE BASIN E OF 80W.

HISPANIOLA...
CURRENTLY A FEW ISOLATED SHOWERS ARE OCCURRING AND WILL REMAIN
ACROSS THE ISLAND THROUGH THE OVERNIGHT HOURS. SATELLITE IMAGERY
INDICATES THAT THE SAHARAN AIR LAYER WILL PROVIDE AN OVERALL
STABLE ATMOSPHERE OVER THE NEXT FEW DAYS. HAZY SKIES ARE
EXPECTED DURING THE NEXT 24 TO 48 HOURS.

ATLANTIC OCEAN...
A NARROW MIDDLE TO UPPER LEVEL TROUGH IS ACROSS THE SW NORTH
ATLC W OF 73W THAT SUPPORTS A 1013 MB LOW CENTERED NEAR 32N78W
AND A SURFACE TROUGH EXTENDING FROM THE LOW TO 30N80W. GENERALLY
AN OVERALL WEAKNESS IN THE SURFACE RIDGING EXTENDING FROM THE
CENTRAL ATLC TO THE GULF OF MEXICO...MAXIMUM MIDDLE TO UPPER
LEVEL DIFFLUENCE IN THE REGION IS GENERATING EXTENSIVE
CLOUDINESS WITH ISOLATED SHOWERS AND TSTMS N OF 25N BETWEEN 74W-
81W. THIS AREA OF TROUGHING...ALONG WITH THE LOW PRESSURE CENTER
IS EXPECTED TO MOVE NORTHEAST AND WELL NORTH OF THE DISCUSSION
AREA OVER THE NEXT 12 TO 24 HOURS. OTHERWISE THE REMAINDER OF
THE SW NORTH ATLC...CENTRAL ATLC...AND EASTERN ATLC ARE UNDER
THE INFLUENCE OF A SURFACE RIDGE ANCHORED BY A 1023 MB HIGH
CENTERED NEAR 28N63W AND A 1028 MB HIGH CENTERED S-SW OF THE
AZORES NEAR 35N30W. EMBEDDED WITHIN THE SOUTHERN PERIPHERY OF
THE RIDGE...MID-LATITUDE ENERGY IS ASSOCIATED WITH A SURFACE
TROUGH ANALYZED FROM 19N40W TO 25N39W. WHILE NO SIGNIFICANT
CONVECTION IS OCCURRING WITH THIS FEATURE...IT IS FORECAST TO
MERGE WITH ENERGY ASSOCIATED WITH THE TROPICAL WAVE ALONG 35W
OVER THE NEXT 24 HOURS. FINALLY...SAHARAN DUST COVERS MUCH OF
THE TROPICAL ATLC AND IS PROVIDING OVERALL STABLE CONDITIONS
THIS EVENING.

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

$$
HUFFMAN


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