[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 302343
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT TUE JUN 30 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
2315 UTC.

...TROPICAL WAVES...

TROPICAL WAVE IS ALONG 28W S OF 13N MOVING W NEAR 20 KT. THIS
WAVE REMAINS ASSOCIATED WITH A DEEP LAYER MOISTURE MAXIMUM AS
OBSERVED ON THE TPW PRODUCT FROM CIMSS AND EXHIBITS A LOW-
LATITUDE INVERTED-V CLOUD SIGNATURE IN THE VICINITY OF THE WAVE
AXIS S OF 9N. SCATTERED MODERATE CONVECTION IS W OF THE WAVE
AXIS FROM 4N-7N BETWEEN 29W-39W AND IS LIKELY ASSOCIATED WITH
THE ITCZ. ALSO OF NOTE...THIS WAVE CONTINUES TO TRACK ACROSS THE
ERN ATLC UNDER A DRY MIDDLE LEVEL SAHARAN AIR LAYER OF DUST...
FURTHER SUPPRESSING ANY DEEP MOIST CONVECTION.

TROPICAL WAVE IS ALONG 54W S OF 13N MOVING W NEAR 12 KT. THE
WAVE MATCHES UP WELL WITH A MAXIMUM IN DEEP LAYER MOISTURE BASED
ON THE TPW PRODUCT FROM CIMSS AND CONTINUES ON THE LEADING EDGE
OF DUST AND A MIDDLE LAYER SAHARAN AIR LAYER TO THE W. SCATTERED
MODERATE CONVECTION IS FROM 8N-12N BETWEEN 54W-61W. THIS
ACTIVITY IS BEING ENHANCED BY AN UPPER LEVEL RIDGE CENTERED OVER
TRINIDAD.

TROPICAL WAVE IS ALONG 92W/93W S OF 21N MOVING W NEAR 18 KT. THE
WAVE REMAINS MORE PROMINENT IN THE E PACIFIC REGION...BUT IS
GENERATING SCATTERED MODERATE CONVECTION ACROSS SRN MEXICO AND
ALONG THE WRN YUCATAN PENINSULA EXTENDING INTO THE FAR ERN BAY
OF CAMPECHE.

...ITCZ...

THE ITCZ AXIS IS CENTERED ALONG 11N15W 9N19W 7N26W 5N30W 3N38W
4N52W. ISOLATED MODERATE CONVECTION IS FROM 3N-6N BETWEEN
11W-24W. SCATTERED MODERATE CONVECTION IS FROM 4N-7N BETWEEN
29W-39W.

...DISCUSSION...

GULF OF MEXICO...
A STATIONARY FRONT IS POSITIONED ACROSS THE NRN GULF EXTENDING
FROM THE W ATLC NEAR JACKSONVILLE FLORIDA TO NEAR NEW ORLEANS
LOUISIANA AND THEN ALONG THE LOUISIANA GULF COAST TO NEAR PORT
ARTHUR TEXAS. LOCATED ALONG THE SRN EXTENT OF A BROAD UPPER
LEVEL TROUGH OVER THE ERN CONUS...THE STATIONARY FRONT IS
GENERATING SCATTERED SHOWERS AND TSTMS ACROSS THE ERN GULF FROM
24N-28N E OF 90W TO OVER THE FLORIDA PENINSULA AND INTO THE W
ATLC. THIS ACTIVITY IS BEING FURTHER ENHANCED BY A BROAD UPPER
RIDGE CENTERED OVER THE NW BAHAMAS EXTENDING TO NEAR 88W. THE
WRN GULF REMAINS UNDER A WEAK AND NARROW HIGH PRESSURE RIDGE
THAT EXTENDS FROM THE YUCATAN CHANNEL TO NEAR GALVESTON TEXAS...
THUS PROVIDING A MAJORITY OF THE GULF WITH LIGHT WINDS TO 15 KT
THIS EVENING.

CARIBBEAN SEA...
A BROAD UPPER LOW DOMINATES THE CENTRAL AND WRN CARIBBEAN
CENTERED NEAR 16N77W WHILE AN UPPER RIDGE EXTENDS FROM SOUTH
AMERICA OVER THE ERN CARIBBEAN AND LESSER ANTILLES. MOIST SWLY
FLOW ALOFT BETWEEN THESE UPPER LEVEL FEATURES IS ENHANCING
SCATTERED SHOWERS AND TSTMS ACROSS NRN COLOMBIA AND NW VENEZUELA
THAT IS SPREADING UPPER LEVEL CONVECTIVE DEBRIS CLOUDINESS
ACROSS THE S/CENTRAL CARIBBEAN. THE UPPER LEVEL RIDGE IS
ENHANCING THE SCATTERED SHOWER AND ISOLATED TSTM ACTIVITY
ASSOCIATED WITH THE TROPICAL WAVE ALONG 54W IN THE WRN TROPICAL
ATLC. LOW LEVEL CONVERGENCE...UPPER LEVEL DIFFLUENCE AND THE
PROXIMITY OF THE E PACIFIC ITCZ AXIS IS GENERATING SCATTERED
SHOWERS AND TSTMS OVER WRN HONDURAS...NICARAGUA AND COSTA RICA.
MODERATE TO STRONG ELY TRADE WINDS COVER MOST OF THE CARIBBEAN
USHERING IN ISOLATED SHOWERS MAINLY OVER THE NE CARIBBEAN.

ATLANTIC OCEAN...
A DISSIPATING COLD FRONT ENTERS THE W ATLC DISCUSSION AREA NEAR
32N77W AND CONTINUES AS A STATIONARY FRONT TO NEAR JACKSONVILLE
FLORIDA AND INTO THE NE GULF OF MEXICO. AN UPPER LEVEL RIDGE IS
CENTERED OVER THE NW BAHAMAS AND EXTENDS TO NEAR 31N. IT IS
PROVIDING A LARGE AREA OF UPPER DIFFLUENCE ACROSS THE W ATLC TO
ENHANCE SCATTERED SHOWERS AND TSTMS N OF 25N W OF 68W. THIS
ACTIVITY EXTENDS ACROSS THE FLORIDA PENINSULA AND STRAITS OF
FLORIDA INTO THE ERN GULF OF MEXICO. THE SAME UPPER RIDGE
CONTINUES EWD TO ANOTHER ANTICYCLONIC CENTER NEAR 26N60W THAT IS
PROVIDING UPPER DIFFLUENCE TO GENERATE ISOLATED SHOWERS ACROSS
THE CENTRAL ATLC N OF 27N BETWEEN 53W-68W. OTHERWISE THE
REMAINDER OF THE ATLC IS INFLUENCED BY A SURFACE RIDGE THAT
EXTENDS FROM SWRN PORTUGAL TO THE MADEIRA ISLANDS TO NEAR 25N65W
THAT IS ANCHORED ON A 1022 MB HIGH CENTERED NEAR 27N34W. A BROAD
AREA OF AFRICAN DUST COVERS THE ERN TROPICAL ATLC S OF 26N TO
THE ITCZ E OF 50W.

$$
HUFFMAN





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