[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 110530
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 AM EDT SAT JUL 11 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.

...TROPICAL WAVES...

A TROPICAL WAVE IS ALONG 35W/36W S OF 19N MOVING W 15-20 KT.
SATELLITE IMAGERY INDICATES THAT THIS WAVE COINCIDES WITHIN A
BROAD AREA OF LOW/MID-LEVEL CYCLONIC TURNING. THE STRONGEST
SIGNAL IS IN THE 600-800 MB LAYER BASED ON SATELLITE-DERIVED
WINDS. DEEP CONVECTION IS ABSENT NEAR THE WAVE SUPPRESSED BY
LOW/MID-LEVEL DRY SAHARAN AIR.

A TROPICAL WAVE EXTENDS FROM 22N63W TO 10N66W MOVING W 15-20 KT.
THIS WAVE HAS BECOME INCREASINGLY STRETCHED NE-SW TONIGHT AS IT
INTERACTS WITH AN UPPER LOW OVER THE CARIBBEAN. SHOWERS AND
TSTMS ARE LOCATED ALONG AND W OF THE WAVE AXIS IN THE UPPER
DIFFLUENT ZONE FROM 15N-17N BETWEEN 67W-70W AND NEAR THE N
PERIPHERY OF THE WAVE FROM 20N-23N BETWEEN 60W-63W. THE N
PORTION WILL LIKELY FRACTURE LATER TODAY WITH SOME OF ITS
ASSOCIATED MOISTURE MOVING NW.

...ITCZ...

THE ITCZ AXIS IS CENTERED ALONG 10N14W 11N32W 7N37W 8N59W.
SCATTERED MODERATE ISOLATED STRONG CONVECTION IS FROM 7N-13N E
OF 19W.

...DISCUSSION...

GULF OF MEXICO...
A LARGE UPPER HIGH OVER THE S CENTRAL PLAINS IS PROVIDING NLY
FLOW AND ADVECTING DRY AIR SOUTHWARD...HELPING TO SUSTAIN A
SURFACE RIDGE ALONG 26N/27N. THE SOUTHERN END OF AN UPPER TROUGH
HAS PINCHED OFF INTO AN UPPER LOW OVER THE E GULF NEAR 24N84W.
INSTABILITY NEAR AND E OF THE UPPER LOW IS GENERATING SCATTERED
SHOWERS AND ISOLATED TSTMS S OF 27N E OF 85W...AS REVEALED BY
DOPPLER RADAR AND LIGHTNING DATA. SCATTERED SHOWERS AND TSTMS
ARE ALSO OCCURRING OVER THE SW BAY OF CAMPECHE ASSOCIATED WITH
UPPER DIFFLUENCE AND LOW-LEVEL CONVERGENCE ALONG THE COAST OF
MEXICO. SFC RIDGING IS EXPECTED TO SHIFT NWD TODAY AND SUN
CAUSING LIGHT AND VARIABLE FLOW OVER THE N WATERS AND MODERATE
ELY WINDS OVER THE S WATERS.

CARIBBEAN SEA...
FRESH TO STRONG TRADE WINDS ARE OCCURRING BETWEEN THE
SUBTROPICAL RIDGE OVER THE CENTRAL ATLC AND A BROAD TROUGH OVER
NORTHERN SOUTH AMERICA...WITH THE STRONGEST FLOW NEAR THE COAST
OF COLOMBIA. AN EARLIER QUIKSCAT PASS CONFIRMED THE STRONG WINDS
NEAR THE COAST OF COLOMBIA AND ENHANCED NE FLOW IN THE WINDWARD
PASSAGE. THESE WINDS WILL REMAIN STRONG OVER THE NEXT SEVERAL
DAYS AS THE SUBTROPICAL RIDGE STRENGTHENS. ALOFT...AN UPPER LOW
IS CENTERED OVER ERN CUBA WITH A SECONDARY LOW OVER THE SE GULF
OF MEXICO. MOIST SLY FLOW E OF THE LOW AND A DIFFLUENT PATTERN
OVER THE SW CARIBBEAN IS PRODUCING A FEW AREAS OF CONVECTION.
SCATTERED SHOWERS AND TSTMS ARE S OF 13N W OF 81W AND OVER THE E
CARIBBEAN FROM 15N-18N BETWEEN 67W-70W ENHANCED BY A TROPICAL
WAVE. SHOWERS AND TSTMS ARE ALSO OCCURRING OVER W CUBA NEAR THE
UPPER LOW OVER THE SE GULF OF MEXICO.

ATLANTIC OCEAN...
THE ATLANTIC DISCUSSION ZONE REMAINS QUITE TONIGHT WITH ONLY A
FEW AREAS OF UNSETTLED WEATHER TO MENTION. SCATTERED SHOWERS AND
TSTMS ARE OCCURRING FROM 25N-28N W OF 77W ASSOCIATED WITH AN
UPPER LOW OVER THE SE GULF AND A DISSIPATING COLD FRONT
EXTENDING FROM 31N71W TO THE NW BAHAMAS. FARTHER E...AN UPPER
LOW NEAR 24N61W AND A W-NW MOVING SFC TROUGH FROM 28N63W TO
23N73W IS PRODUCING SCATTERED SHOWERS AND TSTMS WITHIN 120 NM
OF THE SFC TROUGH AXIS. THE REMAINDER OF THE BASIN IS RELATIVELY
INACTIVE SUPPRESSED BY DEEP LAYER RIDGING AND ASSOCIATED STABLE
AIR. THE SUBTROPICAL RIDGE IS EXPECTED TO STRENGTHEN SLIGHTLY
OVER THE NEXT FEW DAYS INCREASING TRADES OVER THE TROPICS.

$$
CANGIALOSI





This weather bulletin was brought to you by:
www.nashvilleweather.net