[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 090557
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 AM EDT SAT AUG 09 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...
A LOW AMPLITUDE TROPICAL WAVE IS ALONG 33W S OF 16N MOVING W
NEAR 15-20 KT. 850 MB SATELLITE DERIVED VORTICITY AND THE
MIMIC-TPW FROM CIMSS SUPPORT THE WAVE POSITION. A CYCLONIC
TURNING IS OBSERVED ALONG THE WAVE AXIS NEAR 11N. SCATTERED
MODERATE CONVECTION IS MAINLY AHEAD OF THE WAVE AND NEAR THE
INTERSECTION OF THE WAVE AND THE ITCZ FROM 5N-10N BETWEEN
32W-40W. SCATTERED SHOWERS ARE N OF 10N BETWEEN 31W-40W.

A HIGH AMPLITUDE TROPICAL WAVE IS ALONG 52W/53W FROM 11N-25N
MOVING W 15-20 KT. THE WAVE CONTINUES TO SHOW A WELL DEFINED
INVERTED-V CURVATURE ON SATELLITE IMAGERY WITH SCATTERED SHOWERS
NEAR THE N END OF THE WAVE AXIS. THE SSMI-DERIVED TOTAL
PRECIPITABLE WATER INDICATES A BAND OF MOISTURE EXTENDING
NORTH-SOUTH ALONG THE WAVE AXIS. NO DEEP CONVECTION IS OBSERVED.

A TROPICAL WAVE IS OVER THE EASTERN CARIBBEAN ALONG 65W S OF 20N
MOVING W NEAR 20 KT. THE INTERACTION OF THE WAVE WITH AN
UPPER-LEVEL LOW LOCATED N OF THE LEEWARD ISLANDS NEAR 24N60W IS
PRODUCING SCATTERED SHOWERS AND ISOLATED TSTMS ACROSS THE NRN
LEEWARD/VIRGIN ISLANDS AND PUERTO RICO. THIS AREA OF MOISTURE IS
FORECAST BY THE COMPUTER MODELS TO MOVE WNW OF PUERTO RICO AND
MOVE ACROSS HISPANIOLA DURING THE DAY ON SATURDAY. THE WAVE IS
ALSO GENERATING SCATTERED SHOWER ACTIVITY OVER N CENTRAL
VENEZUELA.

A TROPICAL WAVE IS ALONG 84W S OF 21N MOVING W 10-15 KT.
SCATTERED MODERATE CONVECTION IS ASSOCIATED WITH THE WAVE OVER
ERN HONDURAS AND ERN NICARAGUA FROM 11N-16N BETWEEN 82W-85W.
BROAD AREA OF DEEP LAYERED MOISTURE IS OBSERVED ON MIMIC-TPW
PRODUCT COVERING THE WRN CARIBBEAN W OF 80W.

...THE ITCZ...
ITCZ AXIS IS CENTERED ALONG 10N14W 11N31W 9N34W 7N43W 9N57W
9N62W. A LARGE CLUSTER OF MODERATE TO STRONG CONVECTION IS ALONG
THE AFRICAN COAST FROM 8N-14N BETWEEN 14W-20W. THIS ACTIVITY MAY
BE ASSOCIATED WITH A NEW TROPICAL WAVE. SCATTERED MODERATE
CONVECTION IS FROM 8N-11N BETWEEN 25W-29W...AND FROM 4N-9N
BETWEEN 32W-40W.

...DISCUSSION...

GULF OF MEXICO...
AN UPPER-LEVEL HIGH CENTERED OVER THE TEXAS PANHANDLE EXTENDS
A RIDGE OVER THE NRN GULF WATERS N OF 23N WHILE A DEEP LAYERED
TROUGH CONTINUES TO DIG SOUTH OVER THE EASTERN U.S. INTO THE NE
GULF WATERS AND ACROSS NRN FLORIDA. AS OF 09/0300Z...THE
ATTENDANT COLD FRONT HAS MOVED ACROSS THE FLORIDA PANHANDLE E OF
TALLAHASSEE AND INTO THE NE GULF NEAR 30N85W EXTENDING WWD TO
NEW ORLEANS LOUISIANA. THE FRONT WILL CONTINUE MOVING SWD ACROSS
THE N GULF WATERS TONIGHT SLOWLY DISSIPATING DURING THE WEEKEND.
MULTILAYERED CLOUDS WITH EMBEDDED SHOWERS AND TSTMS ARE
AFFECTING THE GULF REGION FROM 27N-29N BETWEEN 82W-86W...
INCLUDING THE CENTRAL FLORIDA PENINSULA. A DRY AIR MASS FOLLOWS
BEHIND THE FRONT AND IS ACROSS THE NE GULF N OF 28N. UPPER-LEVEL
LOW IS ACROSS THE WRN BAY OF CAMPECHE PROVIDING UPPER DIFFLUENCE
TO SUPPORT SCATTERED SHOWERS AND TSTMS ACROSS SRN MEXICO...THE
YUCATAN PENINSULA AND FAR ERN BAY OF CAMPECHE. THE REMAINDER OF
THE GULF IS UNDER THE INFLUENCE OF A RIDGE ANCHORED ON A WEAK
1014 MB HIGH THAT IS LOCATED NEAR 26N91W. WINDS ARE MAINLY LIGHT
AND VARIABLE ACROSS THE AREA N OF 22N.

CARIBBEAN SEA...
AN UPPER-LEVEL LOW IS SPINNING OVER THE CENTRAL BAHAMAS AND
EXTENDS TROUGHING INTO THE NW CARIBBEAN. BROAD UPPER-LEVEL HIGH
IS OVER THE CENTRAL AND ERN CARIBBEAN WITH THE CENTER NEAR THE
ABC ISLANDS. ANOTHER UPPER-LEVEL LOW IS N OF THE LEEWARD ISLANDS
NEAR 24N60W. THE CYCLONIC FLOW ASSOCIATED WITH THIS UPPER LOW
ENVELOPS THE FAR ERN CARIBBEAN. THE INTERACTION OF THIS LOW WITH
THE TROPICAL WAVE ALONG 65W IS GENERATING SCATTERED SHOWER
ACTIVITY OVER THE NE CARIBBEAN. UPPER LEVEL DIFFLUENCE COUPLED
WITH ANOTHER TROPICAL WAVE ALONG 84W IS SUPPORTING SCATTERED
SHOWERS AND TSTMS OVER THE SW CARIBBEAN AND CENTRAL AMERICA FROM
WRN PANAMA TO HONDURAS AND BELIZE. MODERATE TO STRONG EASTERLY
TRADE WINDS ARE BLOWING ACROSS THE BASIN WITH THE STRONGEST
WINDS OFFSHORE THE NRN COLOMBIAN COAST.

ATLANTIC OCEAN...
SEVERAL UPPER-LEVEL LOWS ARE NOTED ACROSS THE DISCUSSION AREA ON
WATER VAPOR IMAGERY. ONE UPPER LOW IS OVER THE CENTRAL BAHAMAS
WITH ASSOCIATED TROUGHING N OF 20N BETWEEN 65W TO ACROSS THE
FLORIDA PENINSULA. IT IS PRODUCING AN AREA OF SCATTERED SHOWERS
AND TSTMS FROM 24N-30N BETWEEN 66W-77W. SCATTERED SHOWERS AND
TSTMS ARE ALSO ASSOCIATED WITH AFOREMENTIONED COLD FRONT DRAPED
ACROSS NRN FLORIDA FROM 28N-32N BETWEEN 72W-80W. THE SECOND
UPPER LOW IS N OF THE LEEWARD ISLANDS AND THE THIRD UPPER LOW IS
OVER THE CENTRAL ATLC NEAR 28N45W. ANOTHER UPPER-LEVEL LOW IS
OVER THE ERN ATLC NEAR 29N23W WITH A TROUGH EXTENDING SW TO
ANOTHER UPPER LOW CENTERED NEAR 22N31W. IN BETWEEN...A PAIR OF
UPPER-LEVEL HIGHS. THE MAIN ONE IS OVER THE TROPICS NEAR 19N44W.
OTHERWISE..THE ATLANTIC IS DOMINATED BY A PAIR OF SURFACE HIGHS.
A 1025 MB HIGH IS LOCATED OVER THE AZORES AND ANOTHER 1025 MB
HIGH IS CENTERED NEAR 33N49W. TIGHT PRESSURE GRADIENT BETWEEN
THE ATLC RIDGE AND LOWER PRESSURE OVER NW AFRICA IS PRODUCING A
SWATH OF NELY WINDS OF 20-25 KT BETWEEN THE MADEIRA/CANARY
ISLANDS AND THE AFRICAN COAST. THE FRONTAL BOUNDARY OVER THE SE
U.S. IS FORECAST TO MOVE INTO THE FAR NW PORTION OF THE AREA
DURING THE DAY ON SATURDAY AND IS EXPECTED TO REMAIN N OF 29N.

$$
HUFFMAN




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