[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 211716
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT MON MAY 21 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1630 UTC.

...TROPICAL WAVES...

TROPICAL WAVE PREVIOUSLY LOCATED NEAR 21W/22W HAS BEEN REMOVED
FROM THE 12Z SURFACE ANALYSIS. VISIBLE SATELLITE IMAGERY HAS
INDICATED NO LOW-LEVEL CIRCULATION PRESENT IN THE REGION.
INSTEAD...NORTH FLOW IS PREDOMINATE IN THE LOWER LEVELS. IN
ADDITION...COMPUTER MODELS...SATELLITE DERIVED VORTICITY...AND
RECENT BUOY OBSERVATIONS ARE NOT SUPPORTIVE OF THE EXISTENCE OF
A TROPICAL WAVE. THE REGION WILL CONTINUE TO BE MONITORED FOR
MORE CONCLUSIVE DATA.

...ITCZ...
ITCZ AXIS IS CENTERED ALONG THE EQUATOR BETWEEN 9E-3W TO 2N10W
4N20W 4N40W AND INTO SOUTH AMERICA NEAR 2N51W. CLUSTERS OF
MODERATE TO STRONG CONVECTION ARE ALONG A SPEED GRADIENT
BOUNDARY FROM THE EQ-4N E OF 9W. ISOLATED MODERATE CONVECTION IS
WITHIN 100 NM NORTH OF THE BOUNDARY BETWEEN 17W-20W AND ALSO
BETWEEN 28W-31W.

...DISCUSSION...
GULF OF MEXICO...
FAIR WEATHER IS DOMINATE ACROSS THE GULF UNDER NEARLY ZONAL FLOW
ALOFT. A SFC HIGH PRES RIDGE RUNNING E-W ALONG 30N/31N REMAINS
IN CONTROL. LIGHT TO MODERATE E-SE WINDS SPAN THE GULF EXCEPT IN
THE STRAIGHTS OF FLORIDA WHERE A TIGHTENED GRADIENT BETWEEN THE
HIGH PRESSURE RIDGE AND A PERSISTENT TROUGH IN THE WESTERN
CARIBBEAN HAVE INCREASED THE WINDS TO 20 KT. THIS STRONG NE
WIND AND SOME INFLUENCE FROM AN OLD FRONTAL BOUNDARY IS
PRODUCING SCATTERED SHOWERS MOVING FROM THE W ATLC ACROSS THE FL
STRAITS AND INTO THE SE GULF. UPPER AIR DIFFLUENCE IS AIDING IN
CONVECTION OVER TEXAS WITH THE ZONAL FLOW TRANSPORTING THE
OUTFLOW/HIGH CLOUDS OVER THE FAR NW GULF.


CARIBBEAN SEA...
SURFACE OBSERVATIONS AND VISIBLE IMAGERY CONTINUE TO INDICATE
THE EXISTENCE OF A SURFACE TROUGH STRETCHING ACROSS THE
CARIBBEAN FROM CENTRAL CUBA NEAR 22N80W TO PANAMA NEAR 9N82W
WITH AN ASSOCIATED LOW PRESSURE NEAR 11N80W. THE TROUGH IS NO
LONGER DRIFTING WESTWARD BUT INSTEAD HAS BECOME NEARLY
STATIONARY ALONG 82W. MODERATE TO STRONG E-SE WINDS COVER THE
CARIBBEAN E OF THE TROUGH WHEREAS LIGHT TO MODERATE NE WINDS
EXIST TO THE WEST. THE NORTHERN HALF OF THE CARIBBEAN REMAINS
FAIRLY TRANQUIL UNDER WLY UPPER FLOW...EXCEPT FOR PATCHES OF
LOW-TOPPED SHOWERS AND TSTMS BETWEEN JAMAICA AND CUBA AND
FURTHER NE IN THE SE BAHAMAS. THIS ACTIVITY IS ASSOCIATED WITH
THE TAIL END OF A W ATLC TROUGH. THE SOUTH CARIBBEAN IS MARKED
BY A CLUSTER OF MODERATE TO STRONG CONVECTION EMBEDDED WITH
ISOLATED TSTMS SOUTH OF 14N BETWEEN 75W AND CENTRAL AMERICA.
THIS CONVECTION IS BEING SUPPORTED BY THE EASTERN EXTENSION OF
THE E PACIFIC ITCZ AND IS ENHANCED BY DIVERGENCE ALOFT.

ATLANTIC OCEAN...
A COLD FRONT EXTENDING FROM A SURFACE LOW WELL NORTH OF THE AREA
CONNECTS TO A TROUGH NEAR 31N62W. THE TROUGH EXTENDS SW ALONG
37N65W 25N69W INTO HAITI NEAR 20N73W. LOW-LEVEL LIFT ALONG THE
BOUNDARY ALONG WITH UPPER DIFFLUENCE BETWEEN THE TROUGH AND A
RIDGE TO THE E IS PRODUCING SCATTERED SHOWERS AND POSSIBLE TSTMS
WITHIN 200 NM AHEAD OF THE TROUGH AXIS. THE SFC FLOW IS QUITE
BRISK IN THIS REGION AS A TIGHTENED PRES GRADIENT HAS SET UP
BETWEEN THE TROUGH AND A 1021 MB HIGH PRES NEAR THE SE CONUS.
THIS STRONG FLOW IS ADVECTING SCATTERED SHOWERS ACROSS THE W
ATLC WATERS TO THE BAHAMAS AND STRAIGHTS OF FLORIDA. A STRONG
1036 MB SURFACE HIGH DOMINATES THE CENTRAL AND EAST ATLC
RESULTING IN FAIR WEATHER CUMULUS ACROSS THE REGION. THE LEADING
EDGE OF AN UPPER TROUGH OVER THE CENTRAL ATLC IS ADVECTING UPPER
CLOUDS/MOISTURE ACROSS THE EASTERN ATLC SOUTH OF 24N.


$$
WADDINGTON




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