[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 251049
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 AM EDT SAT JUN 25 2005

TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL
AMERICA...GULF OF MEXICO...CARIBBEAN SEA...NORTHEASTERN SECTIONS
OF SOUTH AMERICA...AND 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1015 UTC.

...SPECIAL FEATURE...
A SURFACE TROUGH IN THE W ATLC EXTENDS FROM 321N74W THROUGH A
1009 MB LOW IS NE OF THE BAHAMAS NEAR 28N76W TO CUBA NEAR
22N80W. THIS SYSTEM IS BENEATH THE E EDGE OF A MID/UPPER LEVEL
TROUGH WHICH COVERS PORTIONS OF THE GULF...NW CARIBBEAN...AND W
ATLC. STRONG DIFFLUENCE E OF THIS UPPER TROUGH IS GENERATING AN
AREA OF SCATTERED MODERATE/ISOLATED STRONG CONVECTION FROM
23N-32N BETWEEN 67W-75W. SUBTROPICAL OR TROPICAL CYCLONE
DEVELOPMENT IS POSSIBLE WITHIN THE NEXT 24 TO 36 HRS AS THE
SYSTEM MOVES NNW TOWARD THE CAROLINAS.

...TROPICAL WAVES...

FAR E ATLC TROPICAL WAVE IS ALONG 27W/28W S OF 15W MOVING W
10-15 KT. BROAD WAVE IS OBSERVED ON THE FIRST VISIBLE SATELLITE
IMAGES. NO ASSOCIATED DEEP CONVECTION.

CENTRAL ATLC TROPICAL WAVE IS ALONG 40W/41W S OF 12N MOVING W
15-20 KT. WEAK WAVE WITH A SLIGHT V-SHAPED CURVATURE OBSERVED ON
INFRARED SATELLITE IMAGERY. SCATTERED MODERATE/ISOLATED STRONG
CONVECTION CONFINED WITHIN THE ITCZ IS FROM 7N-10N BETWEEN
37W-41W.

W ATLC TROPICAL WAVE IS ALONG 60W S OF 13N MOVING W 10-15 KT.
VERY WEAK LOW AMPLITUDE CURVATURE IS OBSERVED ON INFRARED
SATELLITE IMAGERY. SCATTERED SHOWERS ARE S OF 12N FROM 59W TO
OVER THE WINDWARD ISLANDS.

CENTRAL CARIBBEAN TROPICAL WAVE IS ALONG 75W/76W S OF 20N MOVING
W 15-20 KT. WAVE IS UNDER AN UPPER LEVEL RIDGE THAT CROSS THE
CARIBBEAN FROM CENTRAL AMERICA TO HISPANIOLA. NUMEROUS STRONG
CONVECTION IS S OF 11N W OF 78W TO INLAND OVER E
PANAMA/COLOMBIA. SCATTERED SHOWERS ARE N OF 17N TO INLAND OVER E
CUBA FROM 74W-77W.

STRONG TROPICAL WAVE IN THE W CARIBBEAN IS ALONG 84W/85W S OF
22N MOVING W 10-15 KT. THE WAVE IS INTERACTING WITH A LARGE
MID/UPPER LOW/TROUGH THAT EXTENDS FROM THE W ATLC INTO THE
CARIBBEAN AND A THE RIDGE ACROSS THE CARIBBEAN PRODUCING OVERALL
CLOUDINESS AND SCATTERED SHOWERS/ISOLATED THUNDERSTORMS OVER THE
AREA S OF 20N BETWEEN 77W-85W.

...ITCZ...

ITCZ AXIS IS CENTERED ALONG 10N12W 8N16W 9N29W 9N60W. SCATTERED
MODERATE/STRONG CONVECTION IS WITHIN 220/250 NM N OF THE AXIS
FROM 17W-21W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS
WITHIN 45/60 NM OF A LINE FROM THE COAST OF AFRICA NEAR 7N12W TO
5N16W AND WITHIN 45 NM OF 10N FROM 33W-36W.

...DISCUSSION...

GULF OF MEXICO...
STRONG MID/UPPER LEVEL TROUGH IS OVER THE N GULF WITH AN UPPER
LEVEL LOW CENTERED ALONG THE FLORIDA/ALABAMA BORDER NEAR 31N87W
WITH BROAD CYCLONIC FLOW OVER THE AREA N OF 25N FROM THE W ATLC
TO INLAND OVER TEXAS. THIS IS FORCING STRONG SUBSIDENCE AND DRY
CONTINENTAL AIR OVER THE N GULF N OF 26N ACROSS THE ENTIRE
REGION. A RIDGE AXIS EXTENDS W/E FROM AN UPPER HIGH OVER THE E
PACIFIC ACROSS S MEXICO TO S CENTRAL AMERICA LEAVING THE S GULF
WITH WESTERLY FLOW. THIS IS ALSO ADVECTING PACIFIC TROPICAL
MOISTURE ACROSS THE SW GULF...WITH THE CONVECTION CONFINED TO
THE PACIFIC COAST OF MEXICO/CENTRAL AMERICA AND SCATTERED
SHOWERS IN THE SW GULF S OF 22N W OF 94W INCLUDING THE BAY OF
CAMPECHE. THIS ENTIRE SCENARIO IS LEAVING THE REMAINDER OF THE
GULF RELATIVELY CLOUD AND SHOWER FREE.

CARIBBEAN...
BROAD MID/UPPER LEVEL TROUGH EXTENDS ACROSS CUBA FROM THE GULF
INTO THE W CARIBBEAN N OF 17N FROM 77W-88W. THIS IS KEEPING THE
FAR NW CARIBBEAN CLOUD AND SHOWER FREE. MID/UPPER LEVEL RIDGING
IS FROM CENTRAL AMERICA NEAR THE TIP OF NICARAGUA/HONDURAS E
ALONG 15N77W THEN NE ACROSS HISPANIOLA NEAR 18N72W. INTERACTION
OF THE TROPICAL WAVE IN THE W CARIBBEAN...THE UPPER LEVEL
TROUGH/RIDGE  ARE GENERATING A LARGE AREA OF OVERALL CLOUDINESS
WITH SCATTERED SHOWERS/THUNDERSTORMS ACROSS THE CENTRAL
CARIBBEAN WITHIN 175 NM OF LINE FROM THE TIP OF NICARAGUA/
HONDURAS TO OVER E CUBA NEAR 20N77W. ISOLATED SHOWERS ARE
APPROACHING THE WINDWARD ISLANDS AHEAD OF THE NEXT TROPICAL WAVE
TO ENTER THE CARIBBEAN.

ATLANTIC...
BROAD MID/UPPER TROUGH COVERS THE W ATLC W OF 75W INTO THE GULF
OF MEXICO AND IS THE MAIN FOCUS OF WEATHER TODAY. SEE SPECIAL
FEATURES ABOVE. MID/UPPER LEVEL HIGH IS CENTERED OVER THE S
BAHAMAS NEAR 21N72W WITH A SHARP RIDGE AXIS EXTENDING N TO
32N71W THEN NW OUT OF THE REGION. ANTICYCLONIC FLOW IS FROM
65W-75W. FARTHER E...A DEEP-LAYERED CENTRAL ATLC TROUGH EXTENDS
FROM AN UPPER LOW NEAR 31N44W S ALONG 23N47W THEN SW TO INTO THE
WINDWARD ISLANDS NEAR 13N62W. A SURFACE TROUGH EXTENDS FROM
THROUGH 32N49W SW TO 23N55W. AREA OF SCATTERED SHOWERS/ISOLATED
THUNDERSTORMS IS FROM 25N-31N BETWEEN 41W-49W. A FRONTAL
BOUNDARY IS ALONG THE N PERIPHERY OF THE CENTRAL/WESTERN ATLC
WHICH IS PUSHING OVERCAST CLOUDS WITH SCATTERED SHOWERS INTO THE
AREA N OF 28N FROM 51W-65W. MODERATE/STRONG SUBSIDENCE AND DRY
UPPER AIR COVERS THE CENTRAL AND W TROPICAL ATLC INTO THE E
CARIBBEAN FROM 10N-26N BETWEEN 50W-66W. TO THE SE...BROAD
MID/UPPER LEVEL RIDGE COVERS THE THE REMAINDER OF THE ATLC S OF
25N WITH A MID/UPPER HIGH LOCATED NW OF THE CAPE VERDE ISLANDS
NEAR 19N29W. A SECOND MID/UPPER LEVEL TROUGH COVERS THE NE ATLC
N OF 27N E OF 32W. AT THE SURFACE...A RIDGE AXIS EXTENDS THROUGH
32N35W SSW TO 20N43W.

$$
WALLACE



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