[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 041757
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT THU JUL 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1715 UTC.

...TROPICAL WAVES...
TROPICAL WAVE EXTENDS FROM 14N26W TO 23N25W MOVING W-NW AT 10-15
KT. THE WAVE REMAINS EMBEDDED WITHIN A POLEWARD SURGE OF
MODERATE TO DEEP MOISTURE AS SHOWN ON TOTAL PRECIPITABLE WATER
IMAGERY WITH GREATEST DEFINITION OF THE WAVE AXIS NOTED ON
GLOBAL MODEL DATA AT THE 700 MB LEVEL. SATELLITE WINDS ALSO
CONFIRM THE PRESENCE OF THE WAVE NEAR THIS LOCATION. CONVECTION
REMAINS NON-EXISTENT DUE TO SAHARAN DUST THAT COVERS MUCH OF THE
TROPICAL ATLC N OF 10N E OF 40W.

TROPICAL WAVE EXTENDS FROM 05N49W TO 10N46W TO 14N42W MOVING W
AT 15 KT. SATELLITE PRESENTATION SHOWS THE WAVE AND ASSOCIATED
SHOWER AND TSTM ACTIVITY COINCIDES WITH A BROAD MID-LEVEL 700 MB
TROUGH S OF 22N BETWEEN 38W-54W. ISOLATED MODERATE CONVECTION
IS WITHIN 150 NM WEST OF THE WAVE AXIS.

TROPICAL WAVE EXTENDS FROM 12N71W TO 21N69W MOVING W AT 20 KT.
THE WAVE REMAINS ASSOCIATED WITH A WEAK MID-LEVEL TROUGH
PROGRESSING ACROSS THE CENTRAL CARIBBEAN SEA AND A SMALL PORTION
OF THE SW NORTH ATLC. NO SIGNIFICANT CONVECTION IS NOTED WITH
THE WAVE AT THIS TIME HOWEVER FAST-MOVING WESTWARD ISOLATED
SHOWERS ARE OCCURRING N OF 15N BETWEEN 66W-73W.

...ITCZ/MONSOON TROUGH...
THE MONSOON TROUGH EXTENDS FROM THE AFRICAN COAST NEAR 08N13W TO
09N18W TO 08N28W. THE INTERTROPICAL CONVERGENCE ZONE AXIS
EXTENDS FROM 08N28W TO 08N36W TO 12N42W. SCATTERED MODERATE
CONVECTION IS FROM 03N-10N BETWEEN 10W-29W. ISOLATED MODERATE
CONVECTION IS FROM THE EQUATOR TO 05N BETWEEN 44W-52W.

...DISCUSSION...

GULF OF MEXICO...
AN RELATIVELY AMPLIFIED UPPER LEVEL PATTERN DOMINATES OVER THE
CONUS THIS AFTERNOON WITH A MIDDLE TO UPPER LEVEL LOW CENTERED
OVER MISSOURI THAT IS PROVIDING MUCH OF THE GULF WITH MOIST WEST-
SOUTHWESTERLY FLOW ALOFT. THE TROUGHING SUPPORTS A 1013 MB LOW
CENTERED NEAR 30N87W WHICH IS ALONG A SURFACE TROUGH AXIS
EXTENDING FROM THE LOW CENTER W-SW TO 27N95W. MOST OF THE ACTIVE
WEATHER IS LOCATED SOUTH AND EAST OF THIS BOUNDARY IN MAXIMIZED
LOW-LEVEL MOISTURE CONVERGENCE AND MID-LEVEL DIFFLUENCE.
NUMEROUS SHOWERS AND SCATTERED TSTMS ARE OCCURRING BETWEEN THE
WESTERN COAST OF THE FLORIDA PENINSULA ALONG 81W TO 92W...ALSO
INCLUDING AN AREA S OF 22N E OF 95W OFFSHORE OF THE YUCATAN
PENINSULA. THE LOW IS FORECAST TO DRIFT NORTHWARD AND GRADUALLY
DISSIPATE INLAND WITH THE REMNANT SURFACE TROUGHING DRIFTING
WESTWARD THROUGH MONDAY.

CARIBBEAN SEA...
THE WESTERN CARIBBEAN SEA IS UNDER THE INFLUENCE OF AN UPPER
LEVEL ANTICYCLONIC CIRCULATION CENTERED OVER SOUTHERM MEXICO
NEAR 18N92W WHICH IS PROVIDING PRIMARILY NORTHERLY FLOW W OF
73W. DIFFLUENCE IS MAXIMIZED BENEATH THIS UPPER LEVEL FEATURE
WITH SCATTERED SHOWERS AND TSTMS OCCURRING W OF 87W...INCLUDING
INLAND PORTIONS OF THE SE YUCATAN PENINSULA...BELIZE...
GUATEMALA...AND WESTERN HONDURAS. FARTHER SOUTH...THE MONSOON
TROUGH IS ANALYZED ALONG 08N AND IS PROVIDING FOCUS FOR ISOLATED
SHOWERS AND TSTMS WITHIN 90 NM OF A LINE FROM 09N80W TO 11N84W.
EAST OF 73W...WATER VAPOR IMAGERY INDICATES DRIER AIR IS SLOWLY
PROGRESSING WESTWARD FROM THE EASTERN CARIBBEAN OVER PORTIONS OF
THE CENTRAL CARIBBEAN AND WESTERN VENEZUELA. FINALLY...A WEAK
TROPICAL WAVE ALONG 71W IS FORECAST TO CONTINUE PROVIDING FOCUS
FOR ISOLATED SHOWER ACTIVITY THE NEXT COUPLE DAYS AS IT TRACKS
WEST. WATER VAPOR IMAGERY ALSO INDICATES AN UPPER LEVEL LOW IS
CENTERED NEAR 24N76W DRAWING MOISTURE OVER EASTERN CUBA...THE
WINDWARD PASSAGE...AND WESTERN HISPANIOLA. SCATTERED SHOWERS AND
ISOLATED TSTMS ARE OCCURRING N OF 17N BETWEEN 73W-78W.

HISPANIOLA...
AN UPPER LEVEL LOW IS CENTERED N-NW OF THE ISLAND NEAR 24N76W
AND EXTENDS AN UPPER LEVEL TROUGH AXIS S-SE TO 19N74W. EAST-
SOUTHEASTERLY TRADES CONTINUE TO ADVECT LOW-LEVEL MOISTURE AND
ALONG WITH MID-LEVEL LIFTING DYNAMICS...THE ATMOSPHERE IS
SUPPORTING ISOLATED SHOWERS CURRENTLY. A TROPICAL WAVE ALONG 71W
ALSO EXTENDS ACROSS THE ISLAND IS WILL PROVIDE FOR AFTERNOON
SHOWERS AND TSTMS THROUGH THE OVERNIGHT HOURS.

ATLANTIC OCEAN...
AN UPPER LEVEL LOW IS NOTED ON WATER VAPOR IMAGERY CENTERED NEAR
24N76W THAT IS PROVIDING PORTIONS OF THE SW NORTH ATLC WITH
SCATTERED SHOWERS AND ISOLATED TSTMS FROM 17N-25N BETWEEN 71W-
77W. THIS UPPER LEVEL FEATURE IS LOCATED ABOVE A SURFACE RIDGE
ANCHORED BY A 1030 MB HIGH CENTERED NORTHWEST OF BERMUDA NEAR
34N67W. THE RIDGE IS FORECAST TO MOVE VERY LITTLE THROUGH LATE
SATURDAY WITH A TROPICAL WAVE ALONG 71W TRACKING WESTWARD ON THE
SOUTHERN PERIPHERY OF THE RIDGE ACROSS THE CENTRAL CARIBBEAN SEA
AND GREATER ANTILLES. OTHERWISE...THE REMAINDER OF THE CENTRAL
AND EASTERN ATLC IS UNDER THE INFLUENCE OF SURFACE RIDGING
ANCHORED BY A 1027 MB HIGH CENTERED OVER THE AZORES NEAR 38N26W.

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

$$
HUFFMAN


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