[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 130002
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT TUE JUN 12 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
2315 UTC.

...TROPICAL WAVES...

A TROPICAL WAVE IS ALONG 46W/47W FROM 6N TO 19N CONTINUES MOVING
W AT A HEALTHY 25 KT CLIP. THIS WAVE CONTINUES TO HAVE A LARGE
ENVELOPE OF CYCLONIC TURNING IN THE LOW LEVELS BUT REMAINS
ABSENT OF ANY DEEP CLOUDINESS OR SIGNIFICANT SHOWER ACTIVITY
AS IT TRAVERSES THROUGH THE CORE OF AN UPPER LEVEL TROUGH.

A LOW AMPLITUDE TROPICAL WAVE IS ALONG 55W S OF 11N MOVING W
NEAR 15 KT. THIS WAVE HAS BECOME A BIT MORE CHALLENGING TO
LOCATE IN THE LOW CLOUDS BUT STILL TRACKABLE FOLLOWING A WWD
MOVING CLUSTER OF CONVECTION ON SATELLITE HOVMOLLER DIAGRAMS AND
IN THE LOW TO MID LEVEL SATELLITE DERIVED WINDS. CURRENTLY
...SCATTERED MODERATE CONVECTION IS WITHIN 180 NM W OF THE WAVE
AXIS APPROACHING THE COAST OF S AMERICA.

A TROPICAL WAVE IS IN THE WRN CARIB ALONG 79W/80W S OF 17N
MOVING W 10-15 KT. WHILE THE LOW LEVEL FLOW CLIMATOLOGICALLY
FLOWS CYCLONICALLY AROUND THE OROGRAPHY OF NORTHERN S
AMERICA...THERE APPEARS TO BE SOME ENHANCED TURNING ASSOCIATED
WITH THIS FEATURE. PATCHES OF SCATTERED MODERATE
CONVECTION...MOSTLY FUELED BY UPPER DIFFLUENCE...IS WITHIN 180
NM W OF THE AXIS.

...THE ITCZ...

ITCZ AXIS IS CENTERED ALONG 8N13W 6N25W 4N35W 6N44W 7N58W.
SCATTERED MODERATE ISOLATED STRONG CONVECTION IS WITHIN 60-75 NM
OF 8.5N17W WITH ADDITIONAL ACTIVITY OVER SENEGAL. THIS ACTIVITY
IS LIKELY ASSOCIATED WITH A TROPICAL WAVE WHICH HAS NOT QUITE
COMPLETELY MOVED OFF THE AFRICAN COAST. UPPER AIR TIME SECTIONS
FROM BAMAKO SUGGESTS THIS WAVE PASSED THE STATION ABOUT 24 HOURS
AGO WITH FORWARD EXTRAPOLATION OF THE WAVE PLACING IT ALONG THE
AFRICAN COAST. THIS FEATURE WILL BE ADDED TO THE 00Z ANALYSIS.
ELSEWHERE SCATTERED MODERATE ISOLATED STRONG CONVECTION IS
WITHIN 90-120 NM EITHER SIDE OF AXIS BETWEEN 23W-25W AND FROM
BETWEEN 37W-40W.

...DISCUSSION...

THE GULF OF MEXICO...
MUCH OF THE GULF IS IN A N-NELY UPPER FLOW REGIME BETWEEN AN
UPPER HIGH CENTERED ALONG THE TEXAS COAST NEAR 29N97W AND AN
UPPER LOW SPINNING OVER THE SRN GULF OF MEXICO NEAR 21N91W.
A LARGE DIGGING TROUGH EXTENDING FROM THE N ATLC TO GEORGIA
AND SLIDING SWD IS IMPARTING NWLY FLOW ALOFT OVER THE FAR NE
GULF. CONFLUENT PATTERN OVER THE MOST OF THE GULF CONTINUES TO
ENHANCE SUBSIDENCE/SINKING AIR WHICH IS PROVIDING A STABLE
AIRMASS ALLOWING FOR FAIR SKIES OVER THE GULF. HOWEVER
INSTABILITY AND LIFT ASSOCIATED WITH AN UPPER JET AXIS DICING SE
ACROSS THE DEEP SOUTH IS FUELING A RASH OF SCATTERED STRONG
TSTMS..SOME SEVERE...OVER THE FL PANHANDLE AND EXTREME SE FL AND
THE ADJACENT COASTAL WATERS. AT THE SFC...THE PRES PATTERN
REMAINS WEAK WITH A 1016 MB HIGH JUST S OF BEAUMONT-PORT ARTHUR
TEXAS AND A DISSIPATING TROUGH ALONG 95W. THE NET EFFECT IS
LIGHT AND VARIABLE WINDS...WHICH ARE ANTICIPATED TO PERSIST FOR
ANOTHER DAY OR TWO AS THE WEAK PRES PATTERN REMAINS IN PLACE.
LIGHT WINDS HAVE ALLOWED SEA SURFACE TEMPERATURES TO RISE TO
85-86F...29-30C AT NOAA BUOYS 42001 AND 42003.

THE CARIBBEAN SEA...
THE ACTIVE WEATHER IN THE REGION REMAINS ACROSS THE WRN PORTION
WHERE PATCHES OF SCATTERED MODERATE TO STRONG CONVECTION ARE
GENERALLY W OF 82W AND S OF 21N EXTENDING OVER HONDURAS...YUCATAN
AND BELIZE. THIS ACTIVITY IS ASSOCIATED WITH DIFFLUENCE ALOFT
BETWEEN AN UPPER LOW SPINNING OVER THE SRN GULF OF MEXICO NEAR
21N91W AND A SPRAWLING RIDGE/ANTICYCLONE CENTERED NEAR 14N77W.
ELSEWHERE...A PLUME OF MID-HIGH LEVEL CLOUDINESS AND POSSIBLE
SHOWERS ARE STREAMING ACROSS THE NRN CARIB...N OF 16N...AS
DEBRIS MOISTURE IS PULLED AROUND THE NRN BRANCH OF THE
ANTICYCLONE. THE REMAINDER OF THE CARIB WATERS IS FREE OF
SIGNIFICANT MOISTURE...ALTHOUGH TYPICAL TRADE WIND SHOWERS ARE
POSSIBLE AT ANY GIVEN LOCATION.

THE ATLANTIC OCEAN...
EXTENSIVE STRONG ZONAL AND INCREASINGLY DIFFLUENT UPPER LEVEL
FLOW...TO THE S OF A LARGE AND PERSISTENT OCCLUDED LOW PRES
SYSTEM NEAR 40N66W COVERS THE DISCUSSION AREA W OF 56W. THE
ASSOCIATED JET AXIS RUNS FROM NE FLORIDA TO JUST S OF BERMUDA
THEN NEWD INTO THE N CENTRAL ATLC. SHOWERS AND TSTMS IGNITED
EARLIER TODAY IN THE RIGHT ENTRANCE REGION OF THE JET HAVE
MOVED RAPIDLY SEWD ACROSS THE FL PENINSULA AND ARE NOW SITUATED
OVER PORTIONS OF COLLIER...PALM BEACH AND COASTAL WATERS OF
MIAMI-DADE COUNTY. A LARGE AREA OF SCATTERED SHOWERS AND TSTMS
HAVE ERUPTED WITHIN 90-120 NM EITHER SIDE OF A 23N66W 30N58W
LINE WITHIN THE AREA OF INCREASING UPPER DIFFLUENCE. THE AREA
OF CONVECTION APPEARS TO BE FORMING ALONG AN AREA OF ENHANCED
LOW LEVEL CONVERGENCE WITH NO SIGNATURE AT THE SURFACE AS HIGH
PRESSURE IS EVIDENT IN THE AREA.

FARTHER E...WV IMAGERY SHOWS A WEAK SHORTWAVE RIDGE EXTENDING
NEWD ALONG 20N52W 32N41W. MUCH MORE EXTENSIVE RIDGING STRETCHES
W FROM AFRICA ALONG 22N TO ABOUT 35W. A WEAK SHEARED UPPER
TROUGH LIES BETWEEN THESE RIDGES EXTENDING FROM 32N28W TO AN
UPPER LOW NEAR 23N41W CONTINUING TO 16N51W. THE ASSOCIATED COLD
FRONT HAS NOW PULLED N OF THE REGION. THESE UPPER FEATURES ARE
ONLY PRODUCING PATCHES OF CIRRUS.

ELSEWHERE....HIGH PRES DOMINATES THE AREA ANCHORED BY A NEARLY
STATIONARY 1025 MB CENTER NEAR 29N39W. THIS HIGH IS AIDING IN
THE MOSTLY FAIR WEATHER AND PRODUCING A LARGE AREA OF MODERATE
TRADES ACROSS THE TROPICAL ATLC...ESPECIALLY BETWEEN THE HIGH
ITSELF AND THE LARGE TROPICAL WAVE NOTED ALONG 47W.

$$
COBB


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