[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 210006
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT SAT MAY 20 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
2345 UTC.

...TROPICAL WAVES...
TROPICAL WAVE IS ALONG 24W S OF 8N MOVING W 15 KT. THIS WAVE
CONTINUES TO BE EMBEDDED WITHIN THE ITCZ AXIS...AND ANY CYCLONIC
CIRCULATION ASSOCIATED WITH THIS WAVE IS RATHER BROAD BUT LESS
DISCERNIBLE THAN VISIBLE EARLIER DURING THE DAY...AND SHOULD
BECOME LESS DEFINED AS IT MOVES WESTWARD UNDER A STRONG ATLC
RIDGE PRODUCING STRONG SUBSIDENCE AND A DRY ENVIRONMENT NEAR THE
NORTHERN EXTENSION OF THE WAVE.

TROPICAL WAVE IS ALONG 49W S OF 9N MOVING W 15-20 KT. THIS WAVE
CONTINUES TO EXHIBIT AN INVERTED V-PATTERN EMBEDDED WITHIN THE
ITCZ ALONG WITH SCATTERED MODERATE/ISOLATED STRONG WITHIN 180 NM
W OF THE WAVE AXIS FROM 5N-6N. WIDELY SCATTERED SHOWERS AND
ISOLATED THUNDERSTORMS ARE ELSEWHERE WITHIN 60 NM OF THE WAVE
AXIS 4N-9N. AS STATED IN THE PREVIOUS DISCUSSION...STILL LITTLE
IMPACT IS EXPECTED IN THE CARIBBEAN FROM THIS WAVE OVER THE NEXT
3-5 DAYS AS THE MAJORITY OF THE MOISTURE AND CONVECTION WITH
THIS SYSTEM IS EXPECTED TO MOVE INTO SOUTH AMERICA.

TROPICAL WAVE PREVIOUSLY ALONG 81W/82W S OF 11N IS RELOCATED TO
ALONG 84W/85W S OF 14N MOVING W 10-15 KT BASED ON UPDATED SURFACE
AND STREAMLINE ANALYSES FROM 1800 UTC. SOME ENHANCEMENT OF
SCATTERED MODERATE TO STRONG CONVECTION IS SEEN OVER NICARAGUA
AND SOUTHERN HONDURAS. STRONG UPPER LEVEL SW WINDS ACROSS THE
NORTHERN PART OF THE WAVE ARE IMPINGING ON THE CONVECTION AT
THIS TIME. WAVE IS NOT EXPECTED TO BECOME ANY BETTER DEFINED
OVER THE NEXT 2 DAYS AS MOVES FURTHER WEST INTO THE EASTERN
PACIFIC.

...ITCZ...
ITCZ AXIS IS CENTERED ALONG 10N14W 4N25W 2N31W 2N38W 3N45W TO
INLAND SOUTH AMERICA NEAR 4N52W. SCATTERED STRONG CONVECTION
EXISTS FROM 1N-4N BETWEEN 44W-47W...AND ALSO WITHIN 30 NM OF THE
AXIS BETWEEN 31-33W. SCATTERED MODERATE/ISOLATED STRONG
CONVECTION IS WITHIN 30 NM OF THE AXIS BETWEEN 22W-24W.

...DISCUSSION...
GULF OF MEXICO...
HIGH PRESSURE CONTINUES TO BE THE DOMINANT WEATHER FEATURE HERE
AS A 1019 MB HIGH CENTER IS ANALYZED NEAR 27N86.5W. AS A
RESULT...SKIES CONTINUE TO BE MOSTLY CLEAR WITH ONLY SCATTERED
LOW CLOUDS PRESENT SOUTH OF MAINLY 26N WHERE SCATTERED TO BROKEN
HIGH CLOUDS ARE ALSO NOTED. IN THE UPPER LEVELS...UPPER TROUGH
IS SEEN EXTENDING FROM ACROSS NORTHERN FLORIDA SOUTHWESTWARD TO
EXTREME SOUTHERN TEXAS AND NE MEXICO WHERE A NEARLY STATIONARY
MID/UPPER LEVEL CYCLONIC CIRCULATION IS EVIDENT. MOSTLY STRONG
SUBSIDENCE AND ASSOCIATED DRY/STABLE AIR ACCOMPANIES THE TROUGH
DUE TO UPPER LEVEL CONFLUENCE ACROSS THESE AREA. CONDITIONS IN
THE GULF ARE EXPECTED TO CHANGE LITTLE OVER THE NEXT FEW DAYS
AS HIGH PRESSURE REMAINS IN PLACE...HOWEVER TROPICAL MOISTURE
JUST SOUTH OF THE GULF ACROSS THE NW CARIBBEAN MAY PUSH FURTHER
NORTH AND BEGIN TO INFLUENCE THE SOUTHERN PORTIONS OF THE GULF
ON SUNDAY...AND POSSIBLE BECOME MORE WIDESPREAD OVER THE CENTRAL
AND EASTERN GULF WITH TIME AS SUGGESTED BY COMPUTER MODELS.

CARIBBEAN SEA AND ATLANTIC OCEAN W OF 55W...
AN UPPER LEVEL TROUGH/RIDGE PATTERN REMAINS IN PLACE ACROSS THIS
AREA. AT THE SURFACE...A DISSIPATING STATIONARY FRONT EXTENDS
FROM 32N61W SOUTHWEST TO 27N68.5W WHERE IT BECOMES A TROUGH
SOUTHWESTWARD TO THE CENTRAL BAHAMAS AND CONTINUES SOUTHWEST
INTO THE W CARIBBEAN TO NEAR THE CAYMAN ISLANDS AND SOUTHWARD
TO NEAR SAN ANDRES ISLAND. BROKEN TO OVERCAST MOSTLY MID/HIGH
CLOUDS ALONG WITH WIDELY SCATTERED SHOWERS AND ISOLATED TSTMS
ARE WITHIN 180 NM SE OF THE FRONT/TROUGH N OF 22N. WIDELY
SCATTERED SHOWERS AND TSTMS ARE WITHIN 75-90 NM W OF THE TROUGH
OVER THE CARIBBEAN. SCATTERED STRONG TSTMS ARE ENHANCED OVER
CENTRAL AND ADJACENT WATERS.  FARTHER E...MID/UPPER HIGH IS
LOCATED JUST N OF HISPANIOLA NEAR 21N71W WITH RIDGING EXTENDING
SW TO HONDURAS/NICARAGUA BORDER AND NE TO BEYOND 32N45W. A JET
STREAM BRANCH EXTENDS FROM THE E BAY OF CAMPECHE NORTHEASTWARD
THROUGH 24N84W TO ACROSS S FLORIDA AND CONTINUES NORTHEASTWARD
THROUGH 27N70W TO BEYOND THE AREA NEAR 32N59W. WINDS IN THE
RANGE OF 60-80 KT ARE NOTED WITHIN THIS JET MAINLY W OF 65W.
STRONG MID/UPPER SUBSIDENCE IS NOTED S OF ABOUT 19N AND E OF 80W
WHERE EASTERLY FLOW AT MID AND UPPER LEVELS PREVAILS. MOISTURE
RELATED TO THE SURFACE TROUGH SHOULD GRADUALLY INCREASE CHANCES
OF RAIN FOR THE NW CARIBBEAN INCLUDING THE YUCATAN PENINSULA AND
CUBA OVER THE NEXT 2-3 DAYS AS IT ADVECTS WESTWARD. THE LARGE
VOLCANIC ASH CLOUDS EARLIER DETECTED OVER THE E CARIBBEAN DUE
TO AN ERUPTION OF THE MONTSERRAT VOLCANO THIS MORNING CONTINUES
TO BE SEEN ON SATELLITE IMAGERY FROM 13N-17N BETWEEN 64W-69W.
SMALL ISOLATED SHOWERS AND TSTMS ARE EMBEDDED WITHIN THE AS CLOUD
FROM 15N-17N BETWEEN 63.5W-65W.

THE REMAINDER OF ATLANTIC OCEAN...
A SHARP UPPER LEVEL TROUGH IS OVER THE CNTRL ATLC WITH THE AXIS
EXTENDING THRU 30N43W THROUGH AN UPPER LOW NEAR 23N47W AND INTO
THE DEEP TROPICS NEAR 9N51W. THE LOW IS HELPING TO TRANSPORT
UPPER MOISTURE FROM THE DEEP TROPICS NORTHEASTWARD TO S OF 26N
BETWEEN 35W-42.5W. AN UPPER HIGH IS NEAR 16N30W WITH MID/UPPER
LEVEL RIDGING COVERING THE AREA S OF 17N AND E OF 33W. DIFFLUENCE
S OF THE RIDGE IS ENHANCING ITCZ CONVECTION. MODERATE/STRONG
SUBSIDENCE NOTED FROM 7N-17N E OF 33W. UPPER TROUGH IS MOVING
SE OVER EXTREME NW AFRICA. AT THE SFC...STRONG 1030 MB HIGH
CENTERED NEAR 32N36W COVERS THE ENTIRE REGION SUPPLYING FAIR
WEATHER ACROSS A GOOD PORTION OF THE ATLANTIC OCEAN. TRADE WINDS
ARE RATHER STRONG ACROSS THE AREA AND WILL LIKELY REMAIN THAT
WAY FOR THE NEXT FEW DAYS.

$$
AGUIRRE


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