[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 120533
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 AM EDT WED AUG 12 2009

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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
0515 UTC.

...SPECIAL FEATURES...
TROPICAL DEPRESSION TWO IS CENTERED NEAR 14.8N 31.5W OR ABOUT
475 MILES WEST OF THE SOUTHERNMOST CAPE VERDE ISLANDS 12/0300
UTC MOVING W AT 11 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS
1006 MB. MAXIMUM SUSTAINED WIND SPEED IS 30 KT WITH GUSTS TO 40
KT. SEE LATEST NHC FORECAST ADVISORY UNDER AWIPS/WMO HEADERS
MIATCMAT2/WTNT22 FOR MORE DETAILS. T.D. TWO IS CURRENTLY
EMBEDDED IN A LOW SHEAR ENVIRONMENT WITH SCATTERED MODERATE/
STRONG CONVECTION JUST W OF THE LOW LEVEL CENTER FROM 13N-16N
BETWEEN 31W-35W.

...TROPICAL WAVES...

TROPICAL WAVE IS ALONG 55W S OF 18N MOVING W 10-15 KT. THE WAVE
IS LOCATED WITHIN A BROAD MOISTURE OBSERVED IN TOTAL
PRECIPITABLE WATER IMAGERY WITH MID LEVEL CURVATURE OBSERVED ON
INFRARED SATELLITE IMAGERY. ISOLATED SHOWERS ARE WITHIN 75 NM OF
THE WAVE AXIS N OF 10N.

TROPICAL WAVE IS FROM ALONG 64W S OF 19N MOVING W NEAR 10 KT.
THE AXIS OF THE WAVE IS ORIENTED AT THE LEADING EDGE OF A
MOISTURE MAXIMUM OBSERVED IN TOTAL PRECIPITABLE WATER IMAGERY. A
WEAK AND ILL DEFINED LOW/MID LEVEL CIRCULATION IS ALONG THE WAVE
NEAR 12N. SCATTERED SHOWERS/ISOLATED THUNDERSTORMS ARE WITHIN 75
NM OF THE WAVE AXIS S OF 13N TO INLAND OVER VENEZUELA.

TROPICAL WAVE IS ALONG 79W S OF 15N MOVING W 10-15 KT. WAVE
REMAINS EMBEDDED WITHIN AN AREA OF MODERATE ELY TRADES AS WELL
AS DRY STABLE AIR OVER THE SW CARIBBEAN...THUS THE WAVE AXIS IS
BASED ON CONTINUITY AND IS LIMITING ANY SHOWER ACTIVITY OR
CONVECTION.

...ITCZ...

THE ITCZ AXIS IS CENTERED ALONG 14N16W 15N24W 9N39W 12N54W ALONG
THE N COAST OF VENEZUELA TO OVER COLOMBIA AND E PANAMA INTO THE
E PACIFIC REGION. BROAD AREA OF SCATTERED MODERATE/STRONG
CONVECTION IS FROM 6N-13N BETWEEN 14W-20W AND TO THE COAST OF W
AFRICA. CLUSTERS OF SCATTERED MODERATE/ISOLATED STRONG
CONVECTION ARE FROM 8N-12N BETWEEN 24W-45W.

...DISCUSSION...

GULF OF MEXICO...
A BROAD UPPER TROUGH DOMINATES THE GULF ANCHORED OVER THE W BAY
OF CAMPECHE EXTENDING NE TO OVER THE BIG BEND AREA OF FLORIDA.
MOIST UNSTABLE AIR ALSO DOMINATES THE GULF GENERATING SCATTERED
SHOWERS/THUNDERSTORMS ARE OVER THE N/CENTRAL N OF 27N TO THE
COAST OF SE LOUISIANA BETWEEN 88W-91W. A SEA BREEZE INDUCED
SURFACE TROUGH IS INLAND OVER THE FLORIDA PENINSULA GENERATING
SCATTERED SHOWERS/ISOLATED THUNDERSTORMS INLAND AND WITHIN 30 NM
ALONG THE COAST S OF 29N. A SECOND SURFACE TROUGH IS OVER THE W
YUCATAN/E BAY OF CAMPECHE GENERATING SIMILAR CONVECTION S OF 20N
E OF 93W TO INLAND OVER THE YUCATAN. ISOLATED SHOWERS WITH
POSSIBLE ISOLATED THUNDERSTORMS DOT MUCH OF THE REMAINDER OF THE
CENTRAL GULF. A WEAK SURFACE RIDGE COVERS THE GULF WITH A PAIR
OF 1017 MB HIGHS LOCATED NEAR 27N87W AND 29N92W.

CARIBBEAN SEA...
BROAD UPPER RIDGE DOMINATES MUCH OF THE CARIBBEAN ANCHORED NEAR
16N81W. MOIST SLY UPPER FLOW COVERS THE W CARIBBEAN GENERATING
SCATTERED SHOWERS/ISOLATED THUNDERSTORMS IN THE GULF OF HONDURAS
S OF 18N W OF 85W AND A NARROW LINE OF SIMILAR ACTIVITY
EXTENDING FROM S HAITI TO SE CUBA. ISOLATED SHOWERS DOT THE
REMAINDER OF THE W CARIBBEAN FROM 11N-20N W OF 80W. VERY DRY AIR
ALOFT COVERS THE REMAINDER OF THE CARIBBEAN REGION E OF 80W WITH
THE EXCEPTION OF THE TROPICAL WAVE MOVING OVER THE E CARIBBEAN
ENHANCING SCATTERED SHOWERS OVER THE LESSER ANTILLES.

ATLANTIC OCEAN...
THE DEEP LAYERED RIDGE COVERS THE THE W ATLC TO OVER THE GREATER
ANTILLES E OF 60W ANCHORED BY AN UPPER HIGH NEAR 31N71W AND A
SURFACE 1018 MB HIGH NEAR 30N75W WITH DRY STABLE AIR ALOFT
SUPPRESSING ANY SHOWER ACTIVITY. A PERSISTENT WEAK SURFACE
TROUGH EXTENDS FROM 31N63W TO 26N75W. SCATTERED SHOWERS AND
POSSIBLE ISOLATED THUNDERSTORMS ARE TO THE E WITHIN 60/75 NM OF
LINE FROM 31N57W TO 28N63W. SIMILAR ACTIVITY ARE BETWEEN THE
TROPICAL WAVES OVER THE W TROPICAL ATLC FROM 13N-20N BETWEEN
55W-63W INCLUDING THE LESSER ANTILLES. OTHERWISE...HIGH PRESSURE
DOMINATES THE ATLC WITH A SURFACE RIDGE OVER THE E ATLC ANCHORED
BY A 1030 MB HIGH CENTERED NE OF THE AZORES AND THE SURFACE
RIDGE AXIS EXTENDING THROUGH 32N35W TO 26N58W.

$$
WALLACE





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