[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 300539
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 AM EDT MON JUL 30 2007

TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL
AMERICA...THE GULF OF MEXICO...THE CARIBBEAN SEA...NORTHERN
SECTIONS OF SOUTH AMERICA...AND THE 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 FEATURE...
SURFACE TROUGH IS ALONG 34N72W 27N73W. SYSTEM REMAINS POORLY
ORGANIZED BUT STILL HAS SOME POTENTIAL FOR TROPICAL OR
SUBTROPICAL DEVELOPMENT OVER THE COUPLE OF DAYS AS IT MOVES
NORTH-NORTHEASTWARD AT 10-15 KT. CLUSTERS OF SCATTERED MODERATE
CONVECTION ARE WELL E OF THE TROUGH AXIS WITHIN 90-120 NM OF
LINE 32N67W TO 28N68W.

...TROPICAL WAVES...
TROPICAL WAVE OVER THE E ATLC ALONG 27W EXTENDS FROM 4N TO 19N
AND IS MOVING W NEAR 10 KT. EARLIER QUIKSCAT PASS INDICATED A
SURFACE LOW ALONG THE WAVE AXIS AND THIS WILL BE INCLUDED ON THE
0600 UTC ANALYSIS. SCATTERED MODERATE ISOLATED STRONG CONVECTION
IS CONFINED TO THE INTERSECTION OF THE WAVE AXIS AND THE ITCZ
BETWEEN 25W AND 35W.

TROPICAL WAVE IS OVER THE CENTRAL ATLC ALONG 50W S OF 17N MOVING
W NEAR 12 KT. WAVE IS OF FAIRLY LOW AMPLITUDE COVERING A NARROW
AREA BETWEEN 45W-52W. SCATTERED MODERATE ISOLATED STRONG
CONVECTION IS CONFINED TO THE INTERSECTION OF THE WAVE AXIS AND
THE ITCZ BETWEEN 45W AND 53W.

TROPICAL WAVE IS OVER THE FAR EASTERN CARIBBEAN TILTED FROM
22N60W TO 11N63W INLAND OVER SOUTH AMERICA NEAR 6N63W MOVING W
NEAR 15 KT. BROAD SLIGHT LOW LEVEL TURNING NOTED ALONG THE WAVE
AXIS GENERALLY WITHIN THE AREA FROM 59W-65W. ISOLATED SHOWERS
ARE MOVING ACROSS THE LESSER ANTILLES BUT NO ASSOCIATED DEEP
CONVECTION IS NOTED.

FAR NORTHERN EXTENT OF TROPICAL WAVE IS OVER THE BAY OF CAMPECHE
ACROSS S MEXICO INTO THE E PACIFIC REGION ALONG 93W/94W MOVING W
NEAR 15 KT. WELL DEFINED LOW LEVEL CYCLONIC CIRCULATION IS NOTED
OVER THE EAST PACIFIC WELL SOUTH OF THE GULF OF TEHUANTEPEC.

...THE ITCZ...
ITCZ AXIS IS CENTERED ALONG 14N17W 9N25W 8N38W 9N48W 6N55W.
EXCEPT AS NOTED ABOVE IN ASSOCIATION WITH THE TROPICAL WAVES...
SCATTERED MODERATE CONVECTION IS WITHIN 120-180 NM N OF THE AXIS
BETWEEN 35W AND 45W.

...DISCUSSION...
GULF OF MEXICO...
UPPER LEVEL RIDGE AXIS EXTENDS FROM NE MEXICO ALONG THE TEXAS
COAST THEN EWD ACROSS THE GULF COAST FROM SW LOUISIANA TO THE
FLORIDA PANHANDLE WITH EMBEDDED ANTICYCLONES OVER S CENTRAL
TEXAS AND LOUISIANA. A WEAK UPPER TROUGH EXTENDS OFF THE SE
COAST AND CUTS ACROSS SOUTH FLORIDA TO A SMALL MID/UPPER LEVEL
CYCLONIC CIRCULATION NEAR 25N93W. THE CYCLONIC CIRCULATION WAS
UNDERCUTTING THE RIDGE AS IT MOVED WSW 15 KT. DESPITE THE
PRESENCE OF THE FEATURES UPPER FLOW WAS NELY OVER MOST OF THE
GULF...BECOMING INCREASINGLY DIFFLUENT OVER THE NE GULF TOWARD
THE FLORIDA PANHANDLE. THE GULF WAS VIRTUALLY FREE OF CONVECTION
ALTHOUGH SOME MID LEVEL CLOUD DEBRIS REMAINED OVER THE EXTREME
NE AND SE GULF. AT THE SURFACE...WEAK RIDGE EXTENDS FROM THE W
ATLC ACROSS THE FLORIDA STRAITS THEN NORTHWESTWARD TO THE UPPER
TEXAS COAST.

CARIBBEAN...
A WEAK SHEAR AXIS SLICED ACROSS THE NW THIRD OF THE CARIBBEAN
EXTENDING FROM A TINY CIRCULATION NEAR THE WINDWARD PASSAGE
WESTWARD ALONG 20N. NELY UPPER FLOW WAS N OF THE AXIS AND WAS
ADVECTING MID TO UPPER LEVEL CLOUD DEBRIS OVER THE FAR NW CORNER
OF THE CARIBBEAN. A SMALL UPPER LEVEL RIDGE EXTENDS FROM
COLOMBIA NEAR 10N75W NW TO 17N83W ESSENTIALLY DOMINATING THE
FLOW OVER THE REMAINDER OF THE W CARIBBEAN W OF 74W. MID TO
UPPER LEVEL EASTERLY FLOW AMIDST STRONG SUBSIDENCE COVERS THE
REMAINDER OF THE CARIBBEAN. SUBSIDENCE REGION WAS SUPPRESSING
CONVECTIVE DEVELOPMENT ALONG THE TROPICAL WAVE ENTERING THE FAR
E CARIBBEAN. ITCZ EXTENDS FROM COLOMBIA ACROSS PANAMA AND COSTA
RICA GENERATING SCATTERED SHOWERS/ISOLATED THUNDERSTORMS OVER
NW COLOMBIA AND PANAMA.

ATLANTIC...
REFER TO THE SPECIAL FEATURES SECTION ABOVE FOR THE SURFACE
TROUGH LOCATED OVER THE NW ATLANTIC. AT THE UPPER LEVELS A
NEGATIVELY TILTED TROUGH EXTENDS FROM THE MID-ATLANTIC
SOUTHEAST THROUGH 34N73W THEN TURNS SWWD ALONG 31N74W THROUGH
THE BAHAMAS ACROSS S FLORIDA. FURTHER E UPPER LEVEL ANTICYCLONES
NEAR 25N65W AND 21N55W DOMINATE THE FLOW REGIME OVER THE
ATLANTIC W OF 50W. A WEAK SHEAR AXIS WAS NOTED BETWEEN THE
TWO ANTICYCLONES ALONG 31N55W 21N61W. ANOTHER MORE PRONOUNCED
TROUGH EXTENDS FROM A CYCLONIC CIRCULATION NEAR 30N45W SWD TO
22N47W. AN EXTENSIVE UPPER LEVEL ANTICYCLONE OVER SOUTHERN
MOROCCO NEAR 30N8W AND COVERED THE AREA E OF 30W WITH MODERATE
ELY FLOW. THE MOST RECENT CIMSS SAL ANALYSIS INDICATES AFRICAN
DUST COVERS THE ATLC E OF 40W AND IS BEING DRAWN INTO THE
CIRCULATION ASSOCIATED WITH THE TROPICAL WAVE ALONG 27W THEREBY
SUPPRESSING DEEP CONVECTION ALONG THE WAVE AXIS ITSELF. AT THE
SURFACE...A SURFACE RIDGE E OF 70W ANCHORED BY A 1023 MB HIGH
NEAR 34N54W DOMINATE THE ATLANTIC WITH ONLY SCATTERED TO BROKEN
STABLE STRATOCUMULUS.

$$
COBB




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