[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 190551
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 AM EDT THU JUN 19 2008

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...
TROPICAL WAVE IS ALONG 49W S OF 18N MOVING W NEAR 20 KT. A BROAD
AREA OF CYCLONIC TURNING IS ASSOCIATED WITH THE WAVE. SCATTERED
MODERATE CONVECTION IS FROM 12N-15N BETWEEN 48W-52W. SIMILAR
CONVECTION IS ALSO OBSERVED WITHIN 300 NM BEHIND THE WAVE AXIS
FROM 10N-14N. THE WAVE SHOWS UP VERY WELL ON THE TOTAL
PRECIPITABLE WATER WHERE A GOOD SURGE OF MOISTURE IS NOTED.
MOISTURE ASSOCIATED WITH THIS WAVE IS EXPECTED TO REACH THE
LESSER ANTILLES LATE THU...AND SHOULD AFFECT THE UK/US VIRGIN
ISLANDS AND PUERTO RICO ON FRI.

A TROPICAL WAVE IS OVER THE BAY OF CAMPECHE AND THE ISTHMUS OF
TEHUANTEPEC. ITS AXIS IS ALONG 93W S OF 20 MOVING W NEAR 10 KT.
THIS WAVE IS NOT WELL DEFINED ON SATELLITE IMAGERY AND WITH THE
SHOWER AND THUNDERSTORM ACTIVITY  DEVELOPING INLAND OVER MEXICO
AND THE YUCATAN PENINSULA THE AXIS IS EVEN HARDER TO FIND. THE
WAVE POSITION IS BASED ON CONTINUITY.

...ITCZ...

ITCZ AXIS IS CENTERED ALONG 9N13W 4N25W 6N40W INTO NORTHERN
BRAZIL NEAR 3N52W. A CLUSTER OF SCATTERED MODERATE/ISOLATED
STRONG CONVECTION HAS MOVED OFF THE AFRICAN COAST AND IT APPEARS
TO BE ASSOCIATED WITH A NEW TROPICAL WAVE. HOWEVER...THE EXACT
POSITION IS DIFFICULT TO LOCATE BASED ON CURRENT DATA. WILL WAIT
FOR VIS SATELLITE IMAGERY FOR MORE EVIDENCE. IN ADDITION...THE
HOVMOLLER DIAGRAM IS SHOWING THE WWD PROPAGATION OF THIS
CONVECTIVE ACTIVITY SINCE TWO DAYS AGO. CLUSTERS OF SCATTERED
MODERATE/STRONG CONVECTION ARE N OF THE ITCZ AXIS FROM 4N-9N
BETWEEN 20W-25W. SMALL CLUSTERS OF SCATTERED MODERATE/ISOLATED
STRONG CONVECTION ARE FROM EQUATOR TO 6N BETWEEN 26W-32W...AND
FROM THE EQUATOR TO 3N WEST OF 45W TO THE BRAZILIAN COAST.

...DISCUSSION...

GULF OF MEXICO...
BROAD UPPER RIDGE REMAINS OVER N MEXICO COVERING THE FAR NW GULF
WITH MODERATE TO STRONG SUBSIDENCE. THE REMAINDER OF THE GULF IS
DOMINATED BY AN UPPER LEVEL TROUGH THAT EXTENDS FROM A BROADER
UPPER TROUGH N OF THE AREA ACROSS THE FLORIDA PENINSULA TO THE
BAY OF CAMPECHE. AS OF 03Z...THE ASSOCIATED COLD FRONT ENTERS
THE REGION THROUGH CENTRAL FLORIDA AND EXTENDS OVER THE EASTERN
GULF TO 27N88W. SCATTERED SHOWERS AND TSTMS ARE ALONG THE
FRONTAL BOUNDARY JUST N OF LAKE OKEECHOBEE OVER FLORIDA.
DIFFLUENCE ALOFT ON THE SE SIDE OF THE UPPER TROUGH IS
SUPPORTING THE DEVELOPMENT OF SCATTERED TO NUMEROUS SHOWERS AND
THUNDERSTORMS OVER THE YUCATAN PENINSULA AND GUATEMALA.
OTHERWISE THE REMAINDER OF THE GULF IS ENJOYING FAIR WEATHER
TONIGHT UNDER THE INFLUENCE OF A WEAK SFC RIDGE. A SHORT-WAVE
TROUGH MOVED ACROSS SOUTH FLORIDA YESTERDAY GIVING THE AREA A
RAINY WEDNESDAY. RAINFALL AMOUNTS OF 3 TO 5 INCHES WERE
REPORTED...WITH PROBABLY ISOLATED HIGHER AMOUNTS. A TROPICAL
WAVE IS OVER THE BAY OF CAMPECHE. SEE TROPICAL WAVE SECTION.

CARIBBEAN...
A TROUGH/RIDGE/TROUGH PATTERN IS SEEN OVER THE CARIBBEAN SEA. AS
PREVIOUSLY MENTIONED...A SHORT-WAVE TROUGH IS OVER SOUTH FLORIDA
AND WESTERN CUBA INTO THE NW CARIBBEAN. AN UPPER HIGH LOCATED
JUST SOUTH OF JAMAICA EXTENDS A RIDGE NE THROUGH HISPANIOLA INTO
THE ATLC BEYOND 32N60W. DIFFLUENCE ALOFT BETWEEN THIS RIDGE AND
THE UPPER TROUGH IS GENERATING NUMEROUS SHOWERS/ THUNDERSTORMS
BETWEEN CUBA AND THE BAHAMAS. DOPPLER RADAR INDICATES THAT THIS
CONVECTIVE ACTIVITY IS MOVING AWAY FROM SOUTH FLORIDA AT THIS
TIME. A CLUSTER OF MODERATE TO STRONG CONVECTION IS ALONG THE
ATLC COAST OF COLOMBIA. PATCHES OF LOW LEVEL CLOUDS WITH
EMBEDDED LIGHT SHOWERS ARE OVER THE REMAINDER OF THE BASIN. THE
ATLC RIDGE WILL BUILD SW OVER THE AREA AND STRENGTHEN THROUGH
MON PRODUCING MODERATE TO FRESH TRADE WINDS ACROSS THE BASIN
WITH THE STRONGEST WINDS...AS USUAL JUST OFFSHORE THE COLOMBIAN
COAST.

ATLANTIC...
BROAD UPPER TROUGH COVERS THE E US AND NW ATLC WITH A NARROW
TROUGH EXTENDING INTO THE GULF OF MEXICO. THE ASSOCIATED COLD
FRONT ENTERS THE W ATLC THROUGH A 1009 MB LOW NEAR 32N76W  TO
OVER CENTRAL FLORIDA AND THE E GULF. THE UPPER HIGH IN THE
CARIBBEAN EXTENDS A RIDGE AXIS NE ACROSS HISPANIOLA TO BEYOND
32N60W. A WEAK UPPER-LEVEL TROUGH EXTENDS OVER THE CENTRAL ATLC
WITH THE BASE NEAR THE WINDWARD ISLANDS. BROAD UPPER TROUGH IS
IN THE E ATLC EXTENDING FROM THE MADEIRA ISLANDS TO JUST W OF
THE CAPE VERDE ISLANDS NEAR 15N28W. A SURFACE RIDGE DOMINATES
THE ATLC E OF 70W ANCHORED BY A 1023 MB HIGH NEAR 28N38W AS WELL
AS MODERATE/STRONG SUBSIDENCE AND DRY STABLE AIR. THIS LEAVES
THE ATLC E OF 60W ENJOYING FAIR WEATHER THIS EVENING.

$$
GR/CW





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