[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 300557
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 AM EDT THU JUL 30 2009

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...

A TROPICAL WAVE IS ALONG 31W S OF 24N MOVING W NEAR 10-15 KT.
SATELLITE IMAGERY AND SATELLITE DERIVED WINDS INDICATE A BROAD
LOW TO MID-LEVEL CYCLONIC FLOW IN THE VICINITY OF THE WAVE AXIS.
THIS WAVE ALSO EXHIBITS A HIGH AMPLITUDE DEEP LAYER MOISTURE
MAXIMUM OBSERVED IN TOTAL PRECIPITABLE WATER IMAGERY...WHILE
BEING SURROUNDED BY SAHARAN DUST...SCATTERED MODERATE CONVECTION
REMAINS EMBEDDED WITHIN THE ITCZ AXIS AND IS FROM 8N-13N BETWEEN
25W-39W.

A TROPICAL WAVE IS ALONG 61W S OF 18N MOVING W NEAR 20 KT. THIS
WAVE COINCIDES WITH A DEEP LAYER MOISTURE MAXIMUM OBSERVED IN
TOTAL PRECIPITABLE WATER IMAGERY. NO SIGNIFICANT DEEP CONVECTION
IS CURRENTLY ASSOCIATED WITH THIS WAVE...HOWEVER...SCATTERED
SHOWERS ARE MOVING ACROSS THE LESSER ANTILLES AND SE CARIBBEAN
FROM 10N-16N BETWEEN 58W-66W.

A TROPICAL WAVE IS ALONG 90W S OF 21N MOVING W NEAR 25 KT. THIS
WAVE LIES IN A BROAD AREA OF DEEP LAYER MOISTURE OBSERVED IN
TOTAL PRECIPITABLE WATER IMAGERY ACROSS CENTRAL AMERICA BECOMING
MORE BROAD IN COVERAGE ACROSS THE E PACIFIC REGION. SCATTERED
MODERATE TO STRONG CONVECTION IS FROM 12N-17N BETWEEN 88W-93W.
MORE WIDELY SCATTERED SHOWERS COVER THE NW CARIBBEAN AND YUCATAN
PENINSULA S OF 22N BETWEEN 85W-92W. THIS CONVECTION IS FURTHER
ENHANCED BY UPPER LEVEL RIDGING AND THUS UPPER LEVEL DIFFLUENCE
ACROSS CENTRAL AMERICA.

...ITCZ...

THE ITCZ AXIS IS CENTERED ALONG 12N16W 11N20W 14N28W 13N33W
9N45W 12N59W. CLUSTERS OF SCATTERED MODERATE/ISOLATED STRONG
CONVECTION ARE FROM 8N-13N BETWEEN 17W-39W.

...DISCUSSION...

GULF OF MEXICO...
FAIRLY TRANQUIL WEATHER DOMINATES ACROSS MUCH OF THE GULF OF
MEXICO AS AN UPPER LEVEL ANTICYCLONE IS CENTERED IN THE CENTRAL
GULF NEAR 25N86W. THIS UPPER LEVEL FEATURE ALONG WITH A SURFACE
RIDGE OF HIGH PRESSURE EXTENDING FROM THE W ATLC WATERS ALONG
29N IS PROVIDING MOSTLY CLEAR SKIES AND S-SELY WIND OF 10 TO 15
KT ACROSS THE GULF W OF 86W. HOWEVER...UPPER LEVEL DIFFLUENCE ON
THE ERN PERIPHERY OF THE UPPER LEVEL RIDGE IS GENERATING A FEW
ISOLATED SHOWERS E OF 84W. MOSTLY CONVECTIVE DEBRIS CLOUDINESS
FROM EARLIER ACTIVITY IS ACROSS THE FLORIDA PENINSULA THIS
EVENING. THE OTHER AREA TO NOTE ACROSS THE GULF IS THE TROPICAL
WAVE ALONG 90W THAT IS BRINGING ISOLATED SHOWERS TO THE YUCATAN
CHANNEL S OF 23N AND AREAS W TO 92W INCLUDING THE YUCATAN
PENINSULA AND ERN BAY OF CAMPECHE.

CARIBBEAN SEA...
NORTHERLY UPPER LEVEL WINDS PREVAIL ACROSS MUCH OF THE CARIBBEAN
BASIN AS AN UPPER LEVEL RIDGE EXTENDS FROM AN UPPER LEVEL
ANTICYCLONE CENTERED OVER THE ERN GULF OF MEXICO. THE NLY WINDS
ALOFT ARE KEEPING THE MIDDLE AND UPPER LEVELS OF THE ATMOSPHERE
DRY AND FAIRLY STABLE. HOWEVER...A TROPICAL WAVE ALONG 61W IS
IMPACTING THE FAR ERN CARIBBEAN AND LESSER ANTILLES WITH
INCREASED LOW-LEVEL MOISTURE AND SCATTERED SHOWERS OBSERVED S OF
16N BETWEEN 58W-66W. ACROSS THE WRN CARIBBEAN...THE TROPICAL
WAVE ALONG 90W AND AN UPPER LEVEL DIFFLUENT PATTERN IS
GENERATING WIDELY SCATTERED SHOWERS AND ISOLATED TSTMS FROM
11N-22N W OF 82W...INCLUDING THE GULF OF HONDURAS AND PORTIONS
OF CENTRAL AMERICA. S OF 11N...SCATTERED SHOWERS AND TSTMS ARE
OCCURRING BETWEEN 74W-86W DUE TO UPPER LEVEL DIFFLUENCE AND THE
PROXIMITY OF THE ITCZ AXIS ALONG 9N CROSSING PANAMA. FRESH TO
STRONG TRADE WINDS ARE NOTED ACROSS MUCH OF THE CARIBBEAN WITH
THE STRONGEST WINDS NEAR THE COAST OF COLOMBIA.

ATLANTIC OCEAN...
A SHORTWAVE UPPER LEVEL TROUGH ALONG THE MID-ATLC U.S. SEABOARD
IS ENHANCING SCATTERED SHOWERS AND TSTMS OVER THE SW NORTH ATLC
WATERS COVERING THE AREA FROM 27N TO BEYOND 32N E OF 76W. THIS
ACTIVITY STRETCHES S WITHIN 90 NM OF THE ERN FLORIDA PENINSULA
COAST TO 24N. ENHANCEMENT OF THIS CONVECTION IS DUE IN LARGE
PART TO THE UPPER LEVEL DIFFLUENCE GENERATING ON THE ERN
PERIPHERY OF THE UPPER LEVEL ANTICYCLONE CENTERED OVER THE ERN
GULF OF MEXICO. THE REMAINDER OF THE ATLC IS DOMINATED BY DRY
STABLE AIR AND A BROAD SURFACE RIDGE ANCHORED BY A 1026 MB HIGH
NEAR 33N56W BRINGING GENERALLY FAIR WEATHER ACROSS THE BASIN...
EXCEPT FOR AN AREA OF CLOUDINESS AND POSSIBLE ISOLATED SHOWERS
N OF THE TROPICAL WAVE ALONG 31W FROM 21N-30N BETWEEN 24W-35W.

$$
HUFFMAN



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