[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 091748
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT SAT JUN 09 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 1715 UTC.

...TROPICAL WAVES...

A TROPICAL WAVE HAS BEEN ADDED TO THE 12Z SFC MAP OFF THE COAST
OF AFRICA ALONG 14W/15W S OF 13N ESTIMATED TO BE MOVING W 15-20
KT. THERE IS NOT MUCH DEBATE ABOUT THE EXISTENCE OR PSN OF THIS
WAVE WITH A LARGE AREA...ABOUT 10-12 DEGREES OF LONGITUDE...OF
WELL DEFINED LOW TO MID LEVEL CYCLONIC TURNING EVIDENT ON
SATELLITE IMAGES AND TO SOME DEGREE IN QSCAT DATA. THERE IS ALSO
A POSSIBLE LOW ALONG THE WAVE NEAR 7N WHICH MAY BE ADDED TO THE
18Z ANALYSIS. SFC OBS...MOSTLY STATIONS OVER AFRICA...CLEARLY
INDICATE THIS FEATURE WITH 24-H PRES DROPS IN THE 2-4 MB RANGE
IN DAKAR AND SURROUNDING CITIES. CONVECTION HAS DECREASED SOME
OVER THE PAST SEVERAL HOURS BUT SCATTERED MODERATE STILL EXISTS
FROM 4N-8N BETWEEN 13W-19W.

A TROPICAL WAVE IS ALONG 37W/38W S OF 10N MOVING W 10-15 KT.
THIS LOW AMPLITUDE WAVE IS NOT RECOGNIZABLE IN OBS OR SAT
IMAGES...THEREFORE THE PSN IS BASED ON CONTINUITY. ASSOCIATED
SHOWER ACTIVITY IS LINEAR AND DISCUSSED IN THE ITCZ SECTION.

A TROPICAL WAVE IS PUSHING ACROSS THE LESSER ANTILLES ALONG 62W
S OF 15N MOVING W NEAR 15 KT. AFTER A FLARE UP OF CONVECTION
OVER AND E OF THE WINDWARD ISLANDS THIS MORNING...SHOWER
ACTIVITY APPEARS WEAKER BUT STILL ORGANIZED FROM 11N-16N BETWEEN
54W-61W. NEARLY ALL OF THE ASSOCIATED CLOUDINESS LIES TO THE
E OF THE WAVE AXIS...SHEARED BY STRONG UPPER WESTERLIES.

A TROPICAL WAVE IS IN THE S CENTRAL CARIB ALONG 73W S OF 15N
MOVING W NEAR 15 KT. THERE IS SOME CYCLONIC TURNING IN THE LOWER
CLOUDS...BUT SUSPECT MUCH OF THIS TO JUST BE ASSOCIATED WITH THE
NORMAL BACKGROUND FLOW AROUND THE OROGRAPHY. ISOLATED
SHOWERS/TSTMS ARE WITHIN 120 NM EITHER SIDE OF THE AXIS OVER THE
CARIB PORTION. MORE SIGNIFICANT SCATTERED MODERATE/ISOLATED
STRONG IS OVER WRN COLOMBIA AND THE SW CARIB LIKELY TIED TO THE
ITCZ.

...THE ITCZ...

ITCZ AXIS IS CENTERED ALONG 6N16W 5N24W 3N44W 4N52W 8N58W.
BESIDES FOR CONVECTION DISCUSSED ABOVE...ISOLATED MODERATE IS
WITHIN 60 NM EITHER SIDE BETWEEN 34W-41W. SIMILAR ACTIVITY IS
FROM 8N-11N BETWEEN 54W-56W.

...DISCUSSION...

GULF OF MEXICO...
PRETTY QUIET SATURDAY ACROSS MOST OF THE GULF WATERS WITH A 1020
MB HIGH SETTLING IN THE N CENTRAL GULF NEAR 28N90W. THIS PSN OF
THE HIGH HAS ALLOWED SFC WINDS TO RELAX...EXCEPT FOR THE SW BAY
OF CAMPECHE WHERE QSCAT AND SHIPS SHOW E TO SELY WINDS NEAR 20
KT. IN THE MID AND UPPER LEVELS...THE PATTERN REMAINS CONFLUENT
BETWEEN AN UPPER HIGH OVER S MEXICO NEAR 19N100W AND AN UPPER
LOW ABOVE WRN CUBA. THIS DRY FLOW IS AIDING IN THE WIDESPREAD
FAIR WEATHER. WHILE THE MAJORITY OF THE GULF IS CURRENTLY CLEAR
THERE IS SOME PRECIP NEAR THE EDGES. THE MEXICAN COASTAL WATERS
S OF 24N MAY BE EXPERIENCING SOME DEBRIS SHOWER ACTIVITY FROM
CONVECTIVE BURSTS OVER LAND. SCATTERED SHOWER ACTIVITY IS
PUSHING ACROSS EXTREME S FLA AND THE STRAITS ASSOCIATED WITH
INSTABILITY NEAR THE UPPER LOW. BOTH OF THESE AREAS MAY EXPAND
SOME DURING THE LATE AFTERNOON/EARLY EVENING HOURS.

CARIBBEAN SEA...
SIMILAR TO YESTERDAY AT THIS TIME...THE MOST ACTIVE WEATHER IS
IN THE SW CARIB FROM 9N-12N BETWEEN 77W-82W. A 12 HOUR SAT IR
LOOP SHOWS THIS CONVECTIVE WEATHER EXPANDING AND PUSHING W
SUPPORTED BY THE ITCZ AND ENHANCED IN A PRONOUNCED UPPER
DIFFLUENT ZONE. AN UPPER LOW HAS BEEN DRIFTING TO THE SW NOW
CENTERED OVER WRN CUBA. INSTABILITY NEAR THIS UPPER SYSTEM IS
GENERATING CLOUDS AND ISOLATED SHOWERS N OF 18N E OF
80W...ALTHOUGH MUCH OF THE TSTM ACTIVITY LIES FURTHER N OVER THE
BAHAMAS. THE OTHER AREA OF ORGANIZED PRECIP IS E OF THE LESSER
ANTILLES ASSOCIATED WITH A TROPICAL WAVE. SOME OF THIS MOISTURE
WILL LIKELY MOVE INTO THE AREA OVER THE NEXT DAY OR TWO AFTER
THE WAVE PASSES. TRADES ARE MODERATE TODAY AND SHOULD REMAIN
THAT WAY TOMORROW BEFORE INCREASING DURING THE FIRST PART OF THE
WORK WEEK AS HIGH PRES STRENGTHENS IN THE CENTRAL ATLC.

ATLANTIC OCEAN...
SCATTERED SHOWERS AND TSTMS HAVE BEGAN TO FIRE UP OVER THE
BAHAMAS THIS EARLY AFTERNOON. THIS ENERGY IS ASSOCIATED WITH AN
UPPER LOW THAT IS DRIFTING TO THE SW OVER WRN CUBA.
OTHERWISE...A WEAK SFC HIGH PRES RIDGE RULES THE WRN ATLC WITH A
1018 MB CENTER NEAR 29N71W. FARTHER NE...A LARGE VERTICALLY
STACKED LOW PRES AREA IS LOCATED NEAR 37N61W. THIS SYSTEM IS
PROVIDING SOME SUPPORT FOR A FRONTAL TROUGH WHICH ENTERS THE
AREA NEAR 32N54W AND EXTENDS SW TO 23N64W. SCATTERED SHOWERS ARE
WITHIN 120 NM E OF THIS BOUNDARY.

MUCH OF THE CENTRAL AND EASTERN ATLC DISCUSSION AREA IS UNDER
THE INFLUENCE OF SFC HIGH PRES ANCHORED BY A 1023 MB CENTER NEAR
27N32W RESULTING IN LIGHT TO MODERATE WINDS. WV IMAGERY SHOWS AN
UPPER TROUGH EXTENDING ALONG 32N42W 10N39W AND A SPRAWLING RIDGE
COVERING THE E ATLC WITH THE HIGH CENTERED OVER W AFRICA.
THESE UPPER SYSTEMS ARE NOT PRODUCING MUCH MORE THAN SCATTERED
PATCHES OF CIRRUS.

$$
CANGIALOSI





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