[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 302338
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT FRI AUG 30 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...
TROPICAL WAVE EXTENDS FROM 10N16W TO 20N16W MOVING W AT 5 KT. A
1008 MB LOW IS CENTERED ALONG THE WAVE AXIS NEAR 14N16W.
ALTHOUGH THIS WAVE HAS YET TO FULLY EMERGE OFF THE COAST OF WEST
AFRICA...IT DISPLAYS PLENTY OF SURFACE TO 700 MB VORTICITY WITH
A MAXIMUM IN THE VICINITY OF THE SURFACE LOW AND AREAS TO THE
NORTHWEST TO NEAR 17N19W. SCATTERED MODERATE AND ISOLATED STRONG
CONVECTION IS FROM 13N-16N BETWEEN 16W-19W...WITH ISOLATED
MODERATE CONVECTION ELSEWHERE FROM 06N-12N BETWEEN 08W-18W...AND
FROM 12N-17N BETWEEN 15W-23W.

...TROPICAL WAVES...
TROPICAL WAVE EXTENDS FROM 09N51W TO 19N50W MOVING W AT 10-15
KT. A WEAK AND BROAD 1011 MB LOW IS CENTERED ALONG THE WAVE AXIS
NEAR 12N51W THAT LACKS CONVECTION AT THIS TIME. ACTIVE
CONVECTION WITH THE WAVE IS WELL REMOVED FROM THE LOW CENTER TO
THE NE AS WIDELY SCATTERED MODERATE CONVECTION IS FROM 14N-19N
BETWEEN 42W-50W IN THE AREA OF MAXIMUM LOW-LEVEL MOISTURE
CONVERGENCE.

TROPICAL WAVE EXTENDS FROM 11N73W TO 22N70W MOVING W-NW AT 10-15
KT. OVERALL THE WAVE COINCIDES WITH WEAK SURFACE TO 700 MB LOW-
LEVEL TROUGHING...HOWEVER SOME OF THE ENERGY ASSOCIATED WITH THE
WAVE CONTINUES TO FRACTURE AWAY TO THE NORTH-NORTHWEST AS A MID-
LATITUDE TROUGH IS LOCATED TO THE NORTH OVER THE SW NORTH ATLC.
SCATTERED MODERATE CONVECTION IS OCCURRING ACROSS NORTHERN
VENEZUELA FROM 10N-12N BETWEEN 70W-74W...AND ACROSS HISPANIOLA
FROM 17N-20N BETWEEN 67W-73W.

...ITCZ/MONSOON TROUGH...
THE MONSOON TROUGH EXTENDS FROM THE AFRICAN COAST NEAR 13N17W TO
11N22W TO 10N40W. ISOLATED MODERATE CONVECTION IS FROM 04N-08N
BETWEEN 28W-36W.

...DISCUSSION...

GULF OF MEXICO...
WATER VAPOR IMAGERY INDICATES NORTHERLY UPPER LEVEL FLOW
DOMINATES ACROSS MUCH OF THE GULF THIS EVENING WITH RELATIVELY
DRY AND STABLE CONDITIONS ALOFT W OF 84W. THIS OVERALL STABILITY
IS SUPPORTING A 1017 MB HIGH CENTERED IN THE VICINITY OF THE
MISSISSIPPI RIVER DELTA REGION NEAR 29N90W THAT IS PROVIDING
MUCH OF THE BASIN WITH ANTICYCLONIC WINDS GENERALLY LESS THAN 20
KT. THE ONLY AREA OF INTERESTING WEATHER THIS EVENING IS
ASSOCIATED WITH A MIDDLE TO UPPER LEVEL LOW CENTERED OVER THE
FLORIDA STRAITS NEAR 24N81W. THIS UPPER LEVEL LOW IS GENERATING
ISOLATED SHOWERS AND TSTMS FROM 26N-28N BETWEEN 81W-
84W...INCLUDING PORTIONS OF THE INTERIOR CENTRAL FLORIDA
PENINSULA. LOOKING AHEAD...THE GULF IS EXPECTED TO REMAIN FAIRLY
TRANQUIL THIS WEEKEND WITH DRY AIR AND STABILITY ALOFT...AND A
SURFACE RIDGE ANCHORED OVER EASTERN PORTIONS THROUGH THE
UPCOMING WEEKEND. THE RIDGE AXIS IS FORECAST ALONG 26N/27N WITH
GENERALLY LIGHT E-SE WINDS SOUTH OF THE AXIS.

CARIBBEAN SEA...
MIDDLE TO UPPER LEVEL TROUGHING DIPS SOUTHWARD OVER PORTIONS OF
THE WESTERN CARIBBEAN N OF 16N BETWEEN 77W-85W. WITH A WEAKNESS
IN THE SURFACE PRESSURE PATTERN EXTENDING FROM THE SW NORTH ATLC
AND THE OVERALL MID-LEVEL LIFTING DYNAMICS...WIDELY SCATTERED
SHOWERS AND ISOLATED TSTMS ARE OCCURRING N OF 17N BETWEEN 71W-
86W. THIS AREA OF CONVECTION REMAINS MOST ACTIVE IN THE VICINITY
OF THE GREATER ANTILLES ACROSS JAMAICA...HISPANIOLA...AND CUBA.
FARTHER WEST...SCATTERED SHOWERS AND TSTMS ARE OCCURRING ACROSS
INTERIOR PORTIONS OF THE YUCATAN PENINSULA...WESTERN HONDURAS...
AND GUATEMALA. TO THE SOUTH...THE MONSOON TROUGH AXIS EXTENDING
ALONG 10N EXTENDING FROM NORTHERN COLOMBIA TO COSTA RICA WITH
WIDELY SCATTERED SHOWERS AND ISOLATED TSTMS OCCURRING S OF 13N
BETWEEN 70W-85W. LASTLY...UPPER LEVEL TROUGHING IS NOTED ON
WATER VAPOR IMAGERY OVER THE EASTERN CARIBBEAN E OF 72W. LOW-
LEVEL MOISTURE CONVERGENCE WITHIN THE EASTERLY TRADES ALONG WITH
MIDDLE TO UPPER LEVEL LIFT IS GENERATING WIDELY SCATTERED
SHOWERS AND ISOLATED SHOWERS GENERALLY EAST OF A LINE FROM
HISPANIOLA NEAR 18N73W TO NE VENEZUELA NEAR 10N65W. THE MOST
INTENSE CONVECTION THIS EVENING IS NOTED OVER HISPANIOLA IN
ASSOCIATION WITH THE TROPICAL WAVE ALONG 72W AND ACROSS PORTIONS
OF NE VENEZUELA S OF 11N BETWEEN 60W-65W.

HISPANIOLA...
CURRENTLY SCATTERED SHOWERS AND TSTMS REMAIN ACROSS WESTERN
PORTIONS OF THE ISLAND DUE TO PEAK DAYTIME HEATING...
INSTABILITY...AND A TROPICAL WAVE ANALYZED ACROSS THE ISLAND
ALONG 71W. THIS ACTIVITY IS EXPECTED TO GRADUALLY DIMINISH
SOMEWHAT OVER THE NEXT FEW HOURS DUE TO THE LOSS OF DAYTIME
HEATING...HOWEVER THE TROPICAL WAVE...AS IT CONTINUES TO MOVE
OFF TO THE WEST...WILL CONTINUE TO GENERATE ISOLATED SHOWERS AND
TSTMS THROUGH THE OVERNIGHT HOURS. WATER VAPOR IMAGERY INDICATES
AN UPPER LEVEL ANTICYCLONE IS CENTERED SOUTHWEST OF THE ISLAND
NEAR 17N77W AND UPPER LEVEL TROUGHING DOMINATES E OF 72W
PROVIDING FOR PRIMARILY NORTHERLY FLOW ALOFT. MOISTURE CONTINUES
TO ADVECT SOUTHWARD FROM THE SW NORTH ATLC REGION ACROSS THE
GREATER ANTILLES THAT WILL SUSTAIN MOISTURE AND CONVECTIVE
ACTIVITY ACROSS HISPANIOLA ON SATURDAY AND SUNDAY.

ATLANTIC OCEAN...
A MIDDLE TO UPPER LEVEL LOW IS CENTERED OVER THE FLORIDA KEYS
NEAR 24N81W THAT SUPPORTS A SURFACE TROUGH EXTENDING FROM 25N80W
TO 28N81W WITH ISOLATED SHOWERS OCCURRING FROM 23N-28N BETWEEN
74W-78W. STRONGER CONVECTION IS LOCATED OVER INTERIOR PORTIONS
OF CUBA THIS EVENING. FARTHER EAST...OVER THE REMAINDER OF THE
SW NORTH ATLC...MID-LEVEL TROUGHING IS NOTED ON WATER VAPOR
IMAGERY BETWEEN 60W-80W AND IS PROVIDING AN OVERALL UNSTABLE
ENVIRONMENT. A STATIONARY FRONT EXTENDS ALONG 32N BETWEEN 70W-
81W WITH THE ASSOCIATED SURFACE TROUGHING DIPPING SOUTHWARD TO
27N AND A TROPICAL WAVE ALONG 72W EXTENDING NORTHWARD FROM
CENTRAL HISPANIOLA TO 22N70W THAT IS PROVIDING A BROAD AREA OF
WIDELY SCATTERED SHOWERS AND ISOLATED TSTMS FROM 21N-32N BETWEEN
59W-80W. ASIDE FROM THE TROPICAL WAVE PROGRESSING WESTWARD S OF
20N ALONG 51W...A SURFACE RIDGE INFLUENCES THE REMAINDER OF THE
CENTRAL AND EASTERN ATLC ANCHORED BY A 1024 MB HIGH CENTERED
NEAR 33N46W AND A 1029 MB HIGH CENTERED NORTH OF THE AZORES NEAR
43N24W.

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

$$
HUFFMAN


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