[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 192349
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT THU AUG 19 2010

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...METEOROLOGICAL ANALYSIS...WEATHER OBSERVATIONS...AND
RADAR.

BASED ON 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
2315 UTC.

...TROPICAL WAVES...

TROPICAL WAVE EXTENDS FROM 12N33W TO 17N37W TO 24N38W MOVING W
AT 15-20 KT. SATELLITE PRESENTATION INDICATES LOW-LEVEL CYCLONIC
FLOW ALONG THE WAVE AXIS AND THIS WAS ALSO NOTED ON AN EARLIER
MORNING ASCAT PASS AROUND 19/1234 UTC OVER THE NORTHERN PORTION
OF THE WAVE. AN AREA OF MAXIMUM DEEP LAYER MOISTURE IS OBSERVED
ON THE TPW IMAGERY FROM 06N-27N E OF 42W...HOWEVER MUCH OF THIS
MOISTURE IS POSITIONED BENEATH A STABLE SAHARAN AIR LAYER THAT
COVERS MUCH OF THE ATLC E OF 50W. NO SIGNIFICANT DEEP ORGANIZED
CONVECTION ACCOMPANIES THE WAVE THIS EVENING.

TROPICAL WAVE EXTENDS FROM 10N83W TO 17N85W TO 24N85W MOVING W
AT 15-20 KT. LOW-LEVEL CYCLONIC FLOW IS NOTED ON SATELLITE
IMAGERY ACROSS THE WESTERN CARIBBEAN SEA AND CENTRAL AMERICA
THAT ALSO COINCIDES WITH AN AREA OF ENHANCED MOISTURE EVIDENT ON
TPW IMAGERY FROM 09N-22N BETWEEN 78W-90W. SCATTERED MODERATE AND
ISOLATED STRONG CONVECTION IS FROM 11N-24N BETWEEN 78W-91W.
WATER VAPOR IMAGERY ALSO INDICATES AN UPPER LEVEL TROUGH IS
LOCATED ACROSS THE YUCATAN PENINSULA EXTENDING SOUTHWARD TO SW
GUATEMALA THAT IS ENHANCING ONGOING CONVECTION WEST OF THE WAVE.

...ITCZ...

ITCZ AXIS IS CENTERED ALONG 13N38W 11N47W 13N55W. EAST OF THE
TROPICAL WAVE BETWEEN 33W-38W...A MONSOONAL TROUGH IS ANALYZED
AS A SURFACE TROUGH IN PLACE OF THE ITCZ FROM EASTERN MAURITANIA
NEAR 19N06W TO THE W AFRICA COAST NEAR 14N17W AND INTO THE E
ATLC TO 13N27W. THIS MONSOONAL TROUGH HAS PERSISTED OVER THE
PAST FEW DAYS WITH WESTERLY LOW-LEVEL FLOW OBSERVED S OF 13N. AN
EARLIER MORNING ASCAT PASS AROUND 19/1054 UTC INDICATED THE
BEGINNINGS OF A BROAD LOW-LEVEL CIRCULATION SW OF THE CAPE VERDE
ISLANDS NEAR 13N26W. SCATTERED MODERATE AND ISOLATED STRONG
CONVECTION REMAINS UNORGANIZED AND FOCUSED IN THE VICINITY OF
THIS MONSOONAL TROUGH FROM 08N-14N BETWEEN 16W-30W. ELSEWHERE...
SCATTERED MODERATE CONVECTION IS S OF THE ITCZ AXIS FROM 04N-11N
BETWEEN 30W-39W.

...DISCUSSION...

GULF OF MEXICO...
AN UPPER LEVEL ANTICYCLONIC CIRCULATION IS CENTERED OVER CENTRAL
TEXAS NEAR 30N100W AND IS PROVIDING MUCH OF THE GULF WITH NE
UPPER LEVEL FLOW FROM THE FLORIDA PENINSULA TO OVER MUCH OF
MEXICO N OF 20N. THIS UPPER LEVEL RIDGE SUPPORTS A 1018 MB HIGH
CENTERED OVER THE EASTERN GULF NEAR 27N85W. NORTH OF THE RIDGE
AXIS WHICH EXTENDS FROM THE CENTRAL FLORIDA PENINSULA THROUGH
25N90W TO TAMPICO MEXICO...LOW-LEVEL WARM AIR ADVECTION...
CONVERGENT SW WINDS...AND ATMOSPHERIC INSTABILITY ARE SUPPORTING
SCATTERED SHOWERS AND ISOLATED TSTMS OVER THE NW GULF N OF 27N W
OF 92W. ELSEWHERE...NORTH OF A LINE FROM GAINESVILLE FLORIDA TO
27N92W ISOLATED SHOWERS ARE OCCURRING...BUT MOST OF THE ONGOING
ACTIVITY REMAINS OVER INTERIOR PORTIONS OF THE NE GULF COAST
STATES. THE REMAINDER OF THE GULF IS UNDER THE INFLUENCE OF A
TROPICAL WAVE IMPACTING THE SE GULF AND YUCATAN CHANNEL ALONG
86W. SCATTERED SHOWERS AND ISOLATED TSTMS ARE OCCURRING S OF 24N
BETWEEN 84W-92W...INCLUDING THE YUCATAN PENINSULA. SOME OF THE
LOW-LEVEL MOISTURE DRAWN NORTHEAST FROM THE TROPICAL WAVE...AND
AFTERNOON SEABREEZE DYNAMICS ARE GENERATING SCATTERED SHOWERS
AND TSTMS OVER THE SOUTHERN FLORIDA PENINSULA THIS EVENING FROM
24N-28N BETWEEN 80W-84W.

CARIBBEAN SEA...
A TROPICAL WAVE EXTENDS FROM THE YUCATAN CHANNEL TO EASTERN
HONDURAS AND INTO THE SW CARIBBEAN OFF THE COAST OF COSTA RICA
NEAR 10N83W. SCATTERED SHOWERS AND TSTMS COVER MUCH OF THE
WESTERN CARIBBEAN AND CENTRAL AMERICA W OF 78W. AN UPPER LEVEL
TROUGH IS ACROSS THE YUCATAN PENINSULA PROVIDING DIFFLUENCE
ALOFT NEAR THE WAVE AXIS FURTHER SUPPORTING CONVECTION. FARTHER
EAST....THE REMAINDER OF THE BASIN IS UNDER THE INFLUENCE OF AN
UPPER LEVEL LOW CENTERED OVER ANGUILLA NEAR 18N62W. MIDDLE TO
UPPER LEVEL MOISTURE ADVECTING SW FROM THE TROPICAL NORTH ATLC
IS PROVIDING FOR WIDELY SCATTERED SHOWERS AND ISOLATED TSTMS
OVER THE NE CARIBBEAN N OF 16N E OF 68W...INCLUDING INTERIOR
PORTIONS OF PUERTO RICO AND HISPANIOLA THIS EVENING. ELSEWHERE E
OF 78W...OVERALL DRY UPPER LEVEL AIR IS ASSOCIATED WITH THE
UPPER LEVEL LOW S OF 16N...HOWEVER...ISOLATED SHOWERS ARE
OBSERVED OVER THE WINDWARD ISLANDS AND SE CARIBBEAN THIS EVENING.

ATLANTIC OCEAN...
SURFACE RIDGING COVERS THE W ATLC AROUND A 1018 MB HIGH CENTERED
NEAR 27N71W PROVIDING MOSTLY FAIR CONDITIONS ACROSS THE AREA
SUPPORTED BY AN UPPER LEVEL ANTICYCLONE CENTERED NEAR 32N70W.
DAYTIME INSTABILITY IS GENERATING ISOLATED SHOWERS AND TSTMS
OVER THE NW BAHAMAS FROM 23N-27N BETWEEN 76W-80W. FARTHER
EAST...SCATTERED SHOWERS AND ISOLATED TSTMS ARE FOCUSED NEAR A
SURFACE TROUGH ANALYZED FROM 19N-27N ALONG 61W LOCATED IN THE
VICINITY OF AN UPPER LEVEL LOW CENTERED NEAR 18N62W. THE
CONVECTIVE ACTIVITY IS OCCURRING FROM 16N-28N BETWEEN 58W-68W.
ANOTHER SURFACE TROUGH E OF THE LESSER ANTILLES EXTENDS FROM
12N57W TO 23N55W AND IS A WESTWARD PROPAGATING PIECE OF ENERGY
THAT ORIGINATED DAYS AGO FROM A MIDDLE TO UPPER LEVEL TROUGH
OVER THE NE ATLC. ISOLATED SHOWERS ARE WITHIN 120 NM EITHER SIDE
OF THE SURFACE TROUGH. ELSEWHERE ACROSS THE REMAINDER OF THE
CENTRAL AND EASTERN ATLC...SURFACE RIDING DOMINATES N OF 27N
ANCHORED BY A 1019 MB HIGH CENTERED NEAR 32N36W MAINTAINING
GENERALLY FAIR WEATHER. ALOFT...AN UPPER LEVEL ANTICYCLONE
COVERS THE EASTERN ATLC CENTERED NEAR 23N41W.

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

$$
HUFFMAN



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