[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 292351
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT MON JUL 29 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
2315 UTC.

...SPECIAL FEATURES...
A TROPICAL WAVE...THE REMNANTS OF DORIAN...EXTENDS FROM 15N67W
TO 24N64W MOVING W AT 10-15 KT. THE WAVE CORRESPONDS WITH A MID-
LEVEL TROUGH ALONG 65W AND A MID-LEVEL VORTICITY MAXIMUM IN THE
VICINITY OF 22N67W. WHILE NO SURFACE CIRCULATION IS APPARENT AT
THIS TIME...THE DYNAMICS ALOFT CONTINUE TO SUSTAIN SCATTERED
MODERATE CONVECTION FROM 20N-25N BETWEEN 64W-69W.

...TROPICAL WAVES...
TROPICAL WAVE EXTENDS FROM 10N32W TO 18N34W MOVING W AT 5 KT.
THE WAVE AND ENERGY ASSOCIATED WITH IT ARE WRAPPED UP IN A
MONSOONAL GYRE FOCUSED AROUND A BROAD AREA OF LOWER PRESSURE
NOTED AS A 1014 MB LOW CENTERED NEAR 11N33W ALONG THE MONSOON
TROUGH AXIS. CONVECTION REMAINS VERY LIMITED WITH THE WAVE AT
THIS TIME...HOWEVER POSSIBLE ISOLATED SHOWERS ARE FROM 05N-11N
BETWEEN 28W-35W.

...ITCZ/MONSOON TROUGH...
THE MONSOON TROUGH EXTENDS FROM THE AFRICAN COAST NEAR 14N17W TO
11N33W TO 06N40W. THE INTERTROPICAL CONVERGENCE ZONE AXIS
EXTENDS FROM 06N40W TO 04N45W TO THE EQUATOR NEAR 49W. SCATTERED
MODERATE CONVECTION IS FROM 06N-10N BETWEEN 13W-22W.

...DISCUSSION...

GULF OF MEXICO...
AN UPPER LEVEL ANTICYCLONIC CIRCULATION INFLUENCES MUCH OF
NORTHERN MEXICO...THE SOUTHERN U.S. PLAINS...AND PORTIONS OF THE
SE CONUS CENTERED NEAR 31N102W THAT IS PROVIDING MUCH OF THE
GULF WITH NORTHEASTERLY FLOW ALOFT N OF 22N. WATER VAPOR IMAGERY
ALSO INDICATES THAT THE UPPER LEVEL RIDGE WEAKENS OVER THE
SOUTHERN FLORIDA PENINSULA AS A TROUGH AXIS EXTENDS ALONG 79W IN
THE SW NORTH ATLC. THE UPPER LEVEL RIDGING IS HOWEVER SUPPORTING
A SURFACE RIDGE OF HIGH PRESSRE ANCHORED BY A 1020 MB HIGH
CENTERED NEAR 27N85W. ONE EXCEPTION TO THE RIDGE IS A SURFACE
TROUGH ANALYZED FROM THE FLORIDA PANHANDLE NEAR 31N87W TO 27N90W
IN THE NORTH-CENTRAL GULF. ISOLATED SHOWERS AND TSTMS ARE
OCCURRING IN THE VICINITY OF THIS BOUNDARY N OF 26N BETWEEN 85W-
92W. OTHERWISE...THE ONLY OTHER AREAS OF SIGNIFICANT SCATTERED
SHOWERS AND TSTMS CURRENTLY ARE OCCURRING OVER INLAND PORTIONS
OF THE FLORIDA PENINSULA S OF 29N E OF 82W AND ALONG THE
ADJACENT COASTAL WATERS OF WESTERN CUBA S OF 23N E OF 86W. THE
SURFACE RIDGE IS FORECAST TO GENERALLY REMAIN NEARLY STATIONARY
OVER THE NE GULF THROUGH LATE WEDNESDAY WITH E-SE WINDS
PERSISTING ACROSS THE WESTERN GULF IN THE RANGE OF 10-20 KT.

CARIBBEAN SEA...
AN UPPER LEVEL LOW IS CENTERED OVER THE NW CARIBBEAN NEAR 19N85W
AND AN UPPER LEVEL ANTICYCLONIC CIRCULATION IS CENTERED OVER THE
SW CARIBBEAN NEAR 14N83W. MOST OF THE ACTIVE WEATHER THIS
EVENING IS BEING GENERATING ON THE SOUTHERN PERIPHERY OF THE
UPPER LEVEL LOW AND WITHIN THE INFLUENCE OF THE UPPER LEVEL
RIDGING WHICH IS PROVIDING A MAXIMUM AREA OF DIFFLUENCE OVER THE
WESTERN CARIBBEAN AND PORTIONS OF CENTRAL AMERICA. SCATTERED
SHOWERS AND TSTMS ARE OCCURRING S OF 17N BETWEEN 81W-89W...
INCLUDING WESTERN PANAMA...COSTA RICA...NICARAGUA...HONDURAS...
AND EL SALVADOR. THE SOUTHERN EXTENT OF THIS CONVECTION IS
LIKELY ENHANCED BY THE CLOSE PROXIMITY OF THE MONSOON TROUGH
ANALYZED ALONG 09N/10N FROM NORTHERN COLOMBIA TO SOUTHERN COSTA
RICA. FARTHER EAST...A TROPICAL WAVE EXTENDS ACROSS PUERTO RICO
TO 15N67W AND REPRESENTS THE SOUTHERN PORTION OF THE WAVE
ASSOCIATED WITH THE REMNANTS OF DORIAN. WATER VAPOR IMAGERY
INDICATES A VERY DRY AND STABLE AIR MASS INFLUENCES MUCH OF THE
CENTRAL AND EASTERN CARIBBEAN S OF 18N E OF 80W. THIS IS
RESULTING IN MOSTLY CLEAR SKIES AND FAIR WEATHER CONDITIONS. THE
ONLY EXCEPTIONS ARE LATE AFTERNOON AND EARLY EVENING SCATTERED
SHOWERS AND TSTMS OCCURRING PRIMARILY OVER THE ISLANDS OF
HISPANIOLA...JAMAICA...AND CUBA. THE ONGOING CONVECTION IS
EXPECTED TO DIMINISH OVER THE NEXT FEW HOURS WITH THE LOSS OF
PEAK DAYTIME HEATING AND INSTABILITY.

HISPANIOLA...
CURRENTLY SCATTERED SHOWERS AND TSTMS ARE OCCURRING ACROSS THE
ISLAND AND THIS ACTIVITY IS EXPECTED TO WANE DUE TO THE LOSS OF
PEAK DAYTIME HEATING AND INSTABLITY OVER THE NEXT FEW HOURS. ON
THE SYNOPTIC SCALE...AN UPPER LEVEL LOW IS CENTERED N OF
HISPANIOLA NEAR 25N71W THAT IS FORECAST TO SLOWLY DRIFT
NORTHWESTWARD DURING THE NEXT FEW DAYS. AS THIS OCCURS...THE
ISLAND WILL GRADUALLY FALL WITHIN AN AREA OF SOUTHWESTERLY FLOW
ALOFT AND THIS WILL RESULT IN A HIGHER CHANCE FOR AFTERNOON AND
EARLY EVENING SHOWERS AND TSTMS THROUGH WEDNESDAY. IN
ADDITION...THE REMNANTS OF DORIAN ARE FORECAST TO TRACK NORTH OF
THE ISLAND THROUGH WEDNESDAY...WITH SURFACE TROUGHING EXTENDING
SOUTHWARD PROVIDING ANOTHER MECHANISM TO INITIATE SHOWERS AND
TSTMS.

ATLANTIC OCEAN...
AN UPPER LEVEL TROUGH AXIS EXTENDS ALONG 79W IN THE SW NORTH
ATLC FROM OVER THE CAROLINAS SOUTHWARD TO OVER THE FLORIDA
STRAITS. SEABREEZE INTERACTION ACROSS THE FLORIDA PENINSULA AS
WELL AS MIDDLE TO UPPER LEVEL DIFFLUENCE IS GENERATING SCATTERED
SHOWERS AND TSTMS FROM 23N-28N BETWEEN 76W-83W. ISOLATED SHOWERS
AND TSTMS ARE ALSO OCCURRING FARTHER NORTH IN THE SW NORTH ATLC
WATERS BETWEEN BERMUDA AND THE EASTERN COASTLINE OF THE U.S...
GENERALLY N OF 30N W OF 66W. FARTHER EAST...SURFACE RIDGING
REMAINS IN PLACE ACROSS THE REMAINDER OF THE SW NORTH
ATLC...HOWEVER AN UPPER LEVEL LOW CENTERED NEAR 25N71W IS
PRODUCING ISOLATED SHOWERS AND TSTMS FROM 26N-31N BETWEEN 69W-
73W. OTHERWISE...A TROPICAL WAVE ANALYZED ALONG 66W...THE
REMNANTS OF DORIAN...CONTINUES TO PROGRESS WESTWARD ON THE
SOUTHERN PERIPHERY OF THE SURFACE RIDGING TO THE NORTH ANCHORED
BY A 1025 MB HIGH CENTERED NEAR 33N63W. WIDELY SCATTERED SHOWERS
AND TSTMS ARE OCCURRING FROM 20N-26N BETWEEN 63W-69W. FINALLY...
ACROSS THE CENTRAL ATLC...A MIDDLE TO UPPER LEVEL LOW IS
CENTERED NEAR 23N49W THAT SUPPORTS A WEAK SURFACE TROUGH
ANALYZED FROM 16N46W TO 23N42W. POSSIBLE ISOLATED SHOWERS ARE
OCCURRING WITHIN 150 NM EITHER SIDE OF THE BOUNDARY.

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

$$
HUFFMAN


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