[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 231046
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 AM EDT FRI AUG 23 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1015 UTC.

...TROPICAL WAVES...
TROPICAL WAVE EXTENDS FROM 07N53W TO 16N47W MOVING W AT 10-15
KT. THE WAVE REMAINS LOW-AMPLITUDE AND EMBEDDED WITHIN THE ITCZ
AXIS. CONVECTION REMAINS LIMITED WITH ONLY A FEW ISOLATED
SHOWERS OCCURRING WITHIN 210 NM EITHER SIDE OF THE WAVE AXIS.

TROPICAL WAVE EXTENDS FROM 12N83W TO 17N85W TO 22N85W MOVING W
AT 5-10 KT. THE WAVE REMAINS WITHIN BROAD LOW-LEVEL...SURFACE TO
700 MB...TROUGHING LOCATED ACROSS THE WESTERN CARIBBEAN SEA WITH
TOTAL PRECIPITABLE WATER IMAGERY INDICATING MAXIMUM VALUES
GENERALLY BETWEEN 80W-87W. SCATTERED MODERATE AND ISOLATED
STRONG CONVECTION IS FROM 10N-23N BETWEEN 79W-88W.

...ITCZ/MONSOON TROUGH...
THE MONSOON TROUGH EXTENDS FROM THE AFRICAN COAST NEAR 12N17W TO
10N20W TO 14N29W TO 12N34W TO 12N41W. THE INTERTROPICAL
CONVERGENCE ZONE AXIS EXTENDS FROM 12N41W TO 11N50W. SCATTERED
MODERATE CONVECTION IS FROM 08N-13N BETWEEN 17W-27W. ISOLATED
MODERATE CONVECTION IS FROM 06N-15N BETWEEN 35W-47W. A SURFACE
TROUGH IS ANALYZED NORTH OF THE MONSOON TROUGH AXIS FROM 14N32W
TO 19N39W WITH A WEAK 1011 MB LOW CENTERED ALONG THE AXIS NEAR
17N36W. THIS IS LIKELY ANOTHER IMPULSE OF WESTWARD MOVING ENERGY
OR PERHAPS A TROPICAL WAVE THAT MOVED OFF OF AFRICA EARLIER IN
THE WEEK. LOW-LEVEL CYCLONIC MOTION IS NOTED IN THE CLOUD FIELD
SURROUNDING THE SURFACE LOW WITH ISOLATED MODERATE CONVECTION
OCCURRING FROM 16N-18N BETWEEN 34W-38W.

...DISCUSSION...

GULF OF MEXICO...
UPPER LEVEL DIFFLUENT FLOW IS NOTED ON WATER VAPOR IMAGERY
OCCURRING OVER THE WESTERN GULF DUE TO AN UPPER LEVEL RIDGE
EXTENDING FROM OVER CENTRAL MEXICO TO THE WESTERN GULF NEAR
26N97W. MIDDLE TO UPPER LEVEL DIFFLUENCE IS GENERATING ISOLATED
SHOWERS AND TSTMS OVER THE WESTERN GULF THIS MORNING WEST OF
95W. FARTHER EAST...AN UPPER LEVEL LOW IS CENTERED OVER THE
YUCATAN CHANNEL NEAR 22N86W. THIS UPPER LEVEL FEATURE ALONG WITH
A MID-LEVEL VORTICITY MAXIMUM OVER THE NE GULF NEAR 26N88W AND A
SURFACE TROUGH ANALYZED FROM 23N91W TO 30N88W IS GENERATING
SCATTERED SHOWERS AND WIDELY SCATTERED TSTMS N OF 23N BETWEEN
83W-94W. MOST OF THIS CONVECTIVE ACTIVITY IS FOCUSED SE OF THE
MISSISSIPPI RIVER DELTA REGION FROM 26N-30N BETWEEN 86W-89W.
LOOKING AHEAD...GENERALLY E-SE WINDS ARE EXPECTED TO PREVAIL
THROUGH THE UPCOMING WEEKEND AS A SURFACE RIDGE CONTINUES TO BE
ANCHORED OVER THE SE CONUS AND SW NORTH ATLC.

CARIBBEAN SEA...
AN UPPER LEVEL LOW IS CENTERED OVER THE YUCATAN CHANNEL NEAR
22N86W AND ALONG WITH A TROPICAL WAVE ALONG 84W/85W CONTINUES TO
GENERATE SCATTERED SHOWERS AND TSTMS ACROSS THE WESTERN
CARIBBEAN BETWEEN 79W-89W. THE STRONGEST CONVECTION AT THIS TIME
IS LOCATED OFFSHORE OF NICARAGUA AND EASTERN HONDURAS FROM 11N-
17N BETWEEN 81W-85W. THE WAVE IS EXPECTED TO CONTINUE A SLOW
WESTWARD MOVEMENT OVER THE NEXT 24 TO 48 HOURS BRINGING
INCREASED PRECIPITATION CHANCES TO CENTRAL AMERICA AND THE NW
CARIBBEAN WATERS OVER THE WEEKEND. FINALLY...E-SE TRADES
CONTINUE ACROSS THE EASTERN CARIBBEAN WITH AN UPPER LEVEL LOW
CENTERED OVER PUERTO RICO NEAR 18N67W. ISOLATED SHOWERS ARE
OCCURRING FROM 14N-20N BETWEEN 63W-68W DUE TO MIDDLE AND UPPER
LEVEL DIFFLUENCE EAST OF THE UPPER LEVEL TROUGH AXIS.

HISPANIOLA...
A FEW ISOLATED SHOWERS ARE POSSIBLE THROUGH THE MORNING AND
AFTERNOON HOURS...HOWEVER AN UPPER LEVEL LOW IS CENTERED OVER
PUERTO RICO NEAR 18N67W AND HISPANIOLA LIES ON THE WESTERN AND
RELATIVELY DRIER SIDE OF THIS UPPER LEVEL FEATURE AS NOTED ON
WATER VAPOR IMAGERY THIS MORNING. THE UPPER LEVEL LOW IS
EXPECTED TO DRIFT WESTWARD OVER THE NEXT 24 TO 48 HOURS AND
PROVIDE A MORE FAVORABLE ATMOSPHERE FOR AFTERNOON AND EVENING
CONVECTION. THESE ADDED MIDDLE TO UPPER LEVEL DYNAMICS ALONG
WITH PEAK DAYTIME HEATING AND INSTABILITY WILL INITIATE
AFTERNOON SHOWERS AND TSTMS. ANY ACTIVITY THAT FORMS WILL LIKELY
LAST INTO THE EVENING HOURS AND DIMINISH THEREAFTER.

ATLANTIC OCEAN...
AN UPPER LEVEL RIDGE AXIS EXTENDS OVER THE FLORIDA PENINSULA
EASTWARD TO 27N70W PROVIDING MUCH OF THE SW NORTH ATLC WITH
NORTHWESTERLY FLOW ALOFT. WITH AN MID-LEVEL SHORTWAVE TROUGH
PROGRESSING OFF THE MID-ATLC COAST...MOISTURE AND CLOUDINESS IS
NOTED N OF 28N W OF 68W. WITHIN THE AREA...ISOLATED SHOWERS ARE
POSSIBLE...HOWEVER A SURFACE RIDGE REMAINS THE DOMINATE SURFACE
FEATURE ANCHORED BY A 1019 MB HIGH CENTERED NEAR 30N73W. FARTHER
EAST...A MIDDLE TO UPPER LEVEL TROUGH AXIS EXTENDS FROM 32N54W
SW TO 25N63W. THIS TROUGHING SUPPORTS A WEAK STATIONARY FRONT
ANALYZED FROM 32N55W TO 27N61W. ISOLATED SHOWERS ARE OCCURRING
WITHIN 240 NM EAST OF THE FRONTAL BOUNDARY. OTHERWISE...THE
REMAINDER OF THE CENTRAL AND EASTERN ATLC IS UNDER THE INFLUENCE
OF A SURFACE RIDGE ANCHORED BY A 1024 MB HIGH CENTERED SW OF THE
AZORES NEAR 34N32W.

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

$$
HUFFMAN

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