[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 291750
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT THU JUN 29 2006

TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL
AMERICA...THE GULF OF MEXICO...THE CARIBBEAN SEA...NORTHEASTERN
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...WEATHER OBSERVATIONS...RADAR...
AND METEOROLOGICAL ANALYSIS.

BASED ON 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY
THROUGH 1715 UTC.

...TROPICAL WAVES...
A TROPICAL WAVE IS ALONG 31W SOUTH OF 10N MOVING WEST AROUND 15
KT. NO PRECIPITATION IS DIRECTLY RELATED JUST TO THIS WAVE. ITCZ
SHOWERS AND THUNDERSTORMS ARE FOUND FROM 3N TO 6N BETWEEN 28W
AND 33W.

A TROPICAL WAVE IS ALONG 47W/48W SOUTH OF 10N MOVING WEST 10 TO
15 KT. NO SHOWERS AND THUNDERSTORMS ARE DIRECTLY RELATED JUST TO
THIS WAVE.

A LARGE TROPICAL WAVE IS ACROSS THE U.S. VIRGIN ISLANDS AND THE
EASTERN CARIBBEAN ALONG 65W/66W SOUTH OF 20N MOVING WEST 15 TO
20 KT. THIS WAVE IS INTERACTING WITH A LARGE UPPER-LEVEL
TROUGH... PRODUCING DISORGANIZED CLOUDINESS AND SHOWERS THAT
EXTEND FROM THE EASTERN CARIBBEAN SEA...ACROSS THE LESSER
ANTILLES...AND NORTHWARD INTO THE ATLANTIC FOR A FEW HUNDRED
MILES. THESE SHOWER/TSTM ACTIVITY SHOULD SPREAD ACROSS PORTIONS
OF PUERTO RICO AND HISPANIOLA FOR THE REST OF TODAY AND FRIDAY.
UPPER-LEVEL WINDS REMAIN STRONG ENOUGH TO PROHIBIT ANY
DEVELOPMENT OF THIS SYSTEM INTO A TROPICAL CYCLONE OVER THE NEXT
COUPLE OF DAYS. THE SAN JUAN DOPPLER RADAR IS SHOWING SHOWERS
WITH EMBEDDED TSTMS MOVING ACROSS THESE ISLANDS UNDER A SE WIND
FLOW. BRIEF PERIODS OF LOCALLY HEAVY RAINFALL AND STRONG GUSTY
WINDS...ESPECIALLY OVER HIGHER ELEVATIONS...WILL BE POSSIBLE.
THERE IS A RISK OF FLASH FLOODING AND MUDSLIDES. ST. THOMAS AND
ST. CROIX ARE REPORTING GUSTY WINDS UP TO 22 KT.

A TROPICAL WAVE IS ALONG 96W SOUTH OF 20N MOVING WEST 10 TO 15
KT. THE NORTHERN END OF THE WAVE IS GENERATING A CLUSTER OF
MODERATE/ISOLATED STRONG CONVECTION OVER THE BAY OF CAMPECHE
VERY CLOSE TO VERACRUZ...WHERE 1.56 INCHES OF RAIN FELL DURING
THE LAST 24 HOURS.

...THE ITCZ...
ITCZ AXIS IS CENTERED ALONG 7N14W 3N25W 7N35W 3N45W 5N53W.
SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS WITHIN 80/100
NM ON EITHER SIDE OF THE AXIS WEST OF 40W. SIMILAR CONVECTION IS
SEEN FROM 6N-10N EAST OF 20W.

...DISCUSSION...
THE GULF OF MEXICO...
A CUT-OFF LOW IS OVER NE MEXICO WHILE AN UPPER RIDGE FROM AN
UPPER HIGH ANCHORED OVER CENTRAL AMERICA DOMINATES THE ENTIRE
GULF. ABUNDANT UPPER LEVEL MOISTURE COVERS THE AREA WEST OF 90W.
AT THE SURFACE...WEAK HIGH PRESSURE IS KEEPING RATHER QUIET
CONDITIONS ACROSS THE GULF WITH THE EXCEPTION OF THE SW QUADRANT
WHERE THERE ARE MODERATE/STRONG SHOWERS WITH EMBEDDED TSTMS
THANKS TO THE PRESENCE OF A TROPICAL WAVE. A SURFACE TROUGH
EXTENDS FROM THE FLORIDA PANHANDLE MAINLY WWD ALONG 28N90W TO
THE TEXAS COAST. ISOLATED SHOWERS/THUNDERSTORMS ARE BEHIND THE
SURFACE TROUGH WEST OF 90W. WEAK RIDGE WILL BUILD WESTWARD
ACROSS THE NORTHERN GULF DURING THE NEXT FEW DAYS.

THE CARIBBEAN SEA...
BROAD UPPER RIDGE COVERS THE W CARIBBEAN...CENTRAL AMERICA AND
THE YUCATAN PENINSULA FROM AN UPPER HIGH LOCATED OVER NICARAGUA
NEAR 12N85W. THE RIDGE ALSO EXTENDS NWD ACROSS THE GULF. A
MIDDLE/UPPER LEVEL TROUGH FROM THE W ATLC ENTERS THE CARIBBEAN
ACROSS HISPANIOLA. THIS TROUGH IS INTERACTING WITH THE TROPICAL
WAVE CURRENTLY MOVING ACROSS THE EASTERN CARIBBEAN. TROPICAL
MOISTURE IS BEING ADVECTED OVER CENTRAL AMERICA AND THE NW
CARIBBEAN...ENHANCING SCATTERED MODERATE/ISOLATED STRONG
CONVECTION OVER EASTERN NICARAGUA...NE HONDURAS AND THE GULF OF
HONDURAS. PRESSURE GRADIENT BETWEEN THE ATLC HIGH AND THE
COLOMBIAN LOW IS STILL PRODUCING STRONG TRADE WINDS OFF THE
COLOMBIAN COAST. A GALE WARNING IS IN EFFECT FOR THAT AREA.
ANOTHER TROPICAL WAVE LOCATED EAST OF THE LESSER ANTILLES IS
FORECAST TO MOVE INTO THE EASTERN CARIBBEAN ON SATURDAY.

ATLANTIC OCEAN...
THE SHOWER ACTIVITY BETWEEN BERMUDA AND PUERTO RICO HAS
DIMINISHED. THIS ACTIVITY IS ASSOCIATED WITH A SURFACE TROUGH
THAT EXTENDS FROM 31N66W TO 21N69W AND AN UPPER-LEVEL TROUGH
THAT LIES ALONG 71W/72W ENTERING THE CARIBBEAN SEA ACROSS
HISPANIOLA. A LARGE UPPER HIGH IN THE TROPICAL ATLC IS LOCATED
NEAR 13N45W WITH AN UPPER RIDGE COVERING MOST OF THE TROPICS.
THE REMAINDER OF THE E ATLC N OF 20N IS UNDER THE INFLUENCE OF
AN UPPER TROUGH. AT THE SURFACE...BROAD HIGH PRESSURE COVERS
MOST OF THE ATLC ANCHORED BY 1034 MB HIGH LOCATED MIDWAY BETWEEN
THE AZORES AND BERMUDA. PATCHES OF LOW LEVEL CLOUDS ARE ACROSS
THE OCEAN N OF 20N AND EAST OF 50W. ACCORDING TO THE 28/1500 UTC
CIMSS SAHARAN AIR LAYER AND VIS SATELLITE IMAGERY A BROAD AREA
OF AFRICAN DUST IS SPREADING WWD AND CURRENTLY REACHES 55W.

$$
GR



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