[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 070600
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
205 AM EDT TUE AUG 07 2012

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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
0515 UTC.

...SPECIAL FEATURES...

TROPICAL STORM ERNESTO IS CENTERED NEAR 17.3N 83.3W AT 07/0600
UTC OR ABOUT 195 NM ENE OF ISLA ROATAN HONDURAS AND ABOUT 280 NM
E OF BELIZE CITY MOVING WNW AT 11 KT. ESTIMATED MINIMUM CENTRAL
PRESSURE IS 993 MB. MAXIMUM SUSTAINED WIND SPEED IS 55 KT WITH
GUSTS TO 65 KT. SCATTERED MODERATE AND ISOLATED STRONG
CONVECTION IS FROM 15N-21N BETWEEN 78W-84W. SCATTERED MODERATE
CONVECTION IS ELSEWHERE FROM 12N-24N BETWEEN 76W-90W. SEE LATEST
NHC INTERMEDIATE PUBLIC ADVISORY UNDER AWIPS/WMO HEADERS
MIATCPAT5/WTNT35 KNHC AND THE FULL FORECAST/ADVISORY UNDER
AWIPS/WMO MIATCMAT5/WTNT25 KNHC FOR MORE DETAILS.

...TROPICAL WAVES...

TROPICAL WAVE EXTENDS FROM 12N27W TO 18N23W MOVING W AT 15 KT. A
1009 MB LOW IS CENTERED AT THE SOUTHERN EXTENT OF THE WAVE AXIS
NEAR 12N27W AND AN EARLIER 06/2248 UTC ASCAT PASS DEPICTED THE
CIRCULATION EMBEDDED WITHIN THE MONSOON TROUGH AXIS. A MAXIMUM
IN TOTAL PRECIPITABLE WATER IMAGERY IS ALSO OBSERVED BETWEEN
22W-29W WITH SCATTERED MODERATE CONVECTION OCCURRING FROM
09N-12N BETWEEN 26W-31W.

TROPICAL WAVE EXTENDS FROM 11N64W TO 18N62W MOVING W AT 15 KT.
WEAK CYCLONIC FLOW IS NOTED IN LOW-LEVEL GLOBAL MODEL STREAMLINE
ANALYSES ACROSS THE LEEWARD ISLANDS AS A MOISTURE MAXIMUM IS
SEEN ON TOTAL PRECIPITABLE WATER IMAGERY BETWEEN 57W-65W. AS
EXPECTED...SCATTERED SHOWERS ARE OCCURRING FROM 12N-16N BETWEEN
57W-62W...AND FROM 10N-13N BETWEEN 62W-68W.

...ITCZ/MONSOON TROUGH...

THE MONSOON TROUGH EXTENDS FROM THE AFRICAN COAST NEAR 19N16W TO
12N27W TO 12N38W TO 09N49W. THE INTERTROPICAL CONVERGENCE ZONE
EXTENDS FROM 09N49W TO 10N61W. NO SIGNIFICANT CONVECTION IS
NOTED ON SATELLITE IMAGERY.

...DISCUSSION...

GULF OF MEXICO...
AN UPPER LEVEL LOW CENTERED NEAR 24N96W CONTINUES TO IMPACT MUCH
OF THE WESTERN GULF WATERS W OF 89W WHILE AN UPPER LEVEL RIDGE
AXIS EXTENDS FROM 30N85W OVER THE NE GULF WATERS TO 17N82W IN
THE WESTERN CARIBBEAN SEA. THE UPPER LEVEL LOW REMAINS FAIRLY
BROAD AND OVER THE PAST 24 HOURS...MOISTURE AND SHOWER ACTIVITY
HAS LESSENED TO ONLY A FEW ISOLATED SHOWERS EAST OF THE CENTER
OCCURRING FROM 22N-26N BETWEEN 91W-96W. FURTHER SUPPRESSING ANY
SIGNIFICANT CONVECTION OVER THE WESTERN GULF IS THE PRESENCE OF
A SURFACE RIDGE AXIS EXTENDING FROM 28N90W TO THE EAST-CENTRAL
MEXICO COAST NEAR 22N98W. PRIMARILY LIGHT ANTICYCLONIC WINDS ARE
EXPECTED TO CONTINUE ACROSS THE WESTERN GULF THIS EVENING WITH
EXPECTED STRENGTHENING OF NORTHEAST TO EAST WINDS BY EARLY
WEDNESDAY S OF 24N WITH THE APPROACH OF TROPICAL STORM ERNESTO
ACROSS THE YUCATAN PENINSULA LATE TUESDAY INTO WEDNESDAY. OVER
THE EASTERN GULF THIS EVENING...WEAK SURFACE TROUGHING EXTENDS
FROM 27N86W TO THE YUCATAN CHANNEL NEAR 23N86W AND ALONG WITH
MAXIMUM MIDDLE TO UPPER LEVEL DIFFLUENCE PROVIDED BY THE UPPER
LEVEL RIDGING IS GENERATING SCATTERED SHOWERS AND ISOLATED TSTMS
E OF A LINE FROM THE FLORIDA BIG BEND REGION NEAR 29N83W TO
21N90W. SOME OF THIS ACTIVITY IS LARGELY TIED TO THE FAR OUTER
BANDS OF CONVECTION ASSOCIATED WITH ERNESTO IN THE WESTERN
CARIBBEAN SEA. LOOKING AHEAD...ERNESTO IS FORECAST TO IMPACT THE
YUCATAN PENINSULA OVER THE NEXT FEW DAYS WHILE A WEAK SURFACE
RIDGE AXIS EXTENDS TO THE NORTH ALONG 28N/29N THROUGH FRIDAY.

CARIBBEAN SEA...
TROPICAL STORM ERNESTO CONTINUES TO IMPACT THE WESTERN CARIBBEAN
AS IT TRACKS WEST-NORTHWEST. ERNESTO REMAINS MOVING ON THE
SOUTHERN PERIPHERY OF A MID-LEVEL SUBTROPICAL RIDGE ACROSS THE
SW NORTH ATLC AND EASTERN GULF OF MEXICO WATERS. CONVECTION WITH
ERNESTO REMAINS RATHER SPREAD OUT THIS EVENING ACROSS THE
WESTERN CARIBBEAN AND YUCATAN PENINSULA/CENTRAL AMERICA REGION
WITH SCATTERED SHOWERS AND TSTMS OCCURRING OVER THE AREA FROM
12N-24N BETWEEN 76W-90W. LOW-LEVEL MOISTURE AND WIDELY SCATTERED
SHOWERS TRAIL TO THE EAST ACROSS THE WINDWARD PASSAGE...
HISPANIOLA AND PUERTO RICO FROM 17N-20N BETWEEN 63W-76W. LOCALLY
HEAVY RAINFALL IN ASSOCIATION WITH ERNESTO IS EXPECTED ACROSS
PORTIONS OF HONDURAS AND NICARAGUA...BELIZE...AND THE YUCATAN
PENINSULA WITH THE HIGH LIKELIHOOD OF FLASH FLOODING AND
MUDSLIDES OVER THE HIGHER TERRAIN. ELSEWHERE OVER THE EASTERN
CARIBBEAN...AN UPPER LEVEL ANTICYCLONIC CIRCULATION IS CENTERED
NEAR 12N65W THAT HAS RELATIVELY DRY AIR NOTED S OF 16N E OF 72W.
MOSTLY CLEAR SKIES PREVAIL...HOWEVER...WITH A TROPICAL WAVE
ALONG 63W...ISOLATED SHOWERS ARE POSSIBLE OVER THE WINDWARD AND
ABC ISLANDS THROUGH THE OVERNIGHT PERIOD.

ATLANTIC OCEAN...
UPPER LEVEL TROUGHING IS NOTED ON WATER VAPOR IMAGERY N OF 18N
BETWEEN 50W-65W WITH AN UPPER LEVEL LOW EXTENDING WEST OF THIS
AREA CENTERED NEAR 22N70W. A BROAD-SCALE SURFACE TROUGH AXIS IS
ANALYZED FROM 27N62W TO 20N67W AND IS PROVIDING FOCUS FOR
ISOLATED SHOWERS FROM 22N-29N BETWEEN 56W-61W...AND FROM 20N-25N
BETWEEN 65W-72W. THE REMAINDER OF THE SW NORTH ATLC IS UNDER THE
INFLUENCE OF A SURFACE RIDGE WITH AXIS EXTENDING W-SW FROM A
1023 MB HIGH CENTERED NEAR 33N62W TO THE CENTRAL FLORIDA
PENINSULA. ISOLATED SHOWERS ARE HOWEVER POSSIBLE ACROSS THE
BAHAMAS AND AREAS WEST OF 78W...INCLUDING THE EASTERN FLORIDA
PENINSULA COASTAL ZONES THROUGH THE OVERNIGHT HOURS. FARTHER
EAST...UPPER LEVEL ANTICYCLONIC CIRCULATIONS ARE NOTED ON WATER
VAPOR IMAGERY OVER THE EASTERN ATLC WITH A MEAN CENTER NEAR
23N35W. THE REMNANT LOW OF FLORENCE IS ANALYZED NEAR 16N42W AND
CONTINUES TO MOVE AROUND THE SOUTHWESTERN PERIPHERY OF THE UPPER
LEVEL RIDGING. SCATTERED MODERATE CONVECTION REMAINS VERY
LIMITED AND CONFINED TO THE WEST OF THE LOW-LEVEL CIRCULATION
CENTER FROM 16N-18N BETWEEN 44W-47W. OTHERWISE...THE UPPER LEVEL
RIDGING LARGELY SUPPORTS A SURFACE RIDGE ANCHORED BY A 1025 MB
HIGH CENTERED NEAR 33N35W WITH INFLUENCE N OF 20N BETWEEN
13W-55W.

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

$$
HUFFMAN




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