[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 180946 RRA
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL.
205 AM EDT MON JUL 18 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
0445 UTC.

...SPECIAL FEATURE...

HURRICANE EMILY IS CENTERED NEAR 20.3N 87.3W AT 0600 UTC OR
ABOUT 25 MILES WSW OF COZUMEL MEXICO AND ABOUT 170 MILES ESE OF
PROGRESO MEXICO AT MOVING WNW AT 16 KT. ESTIMATED MINIMUM
CENTRAL PRESSURE IS 955 MB. MAXIMUM SUSTAINED WIND SPEED IS 115
KT WITH GUSTS TO 140 KT MAKING EMILY A CATEGORY FOUR HURRICANE.
SEE THE LATEST FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS
MIATCMAT5/ WTNT25 KNHC AND THE PUBLIC ADVISORY UNDER AWIPS/WMO
HEADERS MIATCPAT5/WTNT35 KNHC FOR MORE DETAILS. EMILY IS MOVING
IN OVER THE YUCATAN PENINSULA. THE UPPER LEVEL OUTFLOW IS MOST
IMPRESSIVE IN ALL BUT HE S QUADRANT. NUMEROUS STRONG CONVECTION
COVERS THE AREA FROM 18N-21N BETWEEN 86W-88W WHICH INCLUDES THE
COASTAL AREAS OF THE NE YUCATAN PENINSULA AND THE ISLAND OF
COZUMEL. SCATTERED MODERATE/STRONG CONVECTION COVERS A LARGER
AREA FROM 18N-23.5N BETWEEN 82.5W-88.5W INCLUDING W CUBA INTO
THE GULF OF MEXICO. THE FORECAST TRACK WILL TAKE EMILY ACROSS
THE YUCATAN AND INTO THE GULF OF MEXICO LATER TODAY.

...TROPICAL WAVES...

EASTERN MOST TROPICAL WAVE IS ALONG 31W S OF 18N MOVING W NEAR
20 KT. WEAK LOW LEVEL CURVATURE IS OBSERVED NEAR 15N ON INFRARED
SATELLITE IMAGERY. SCATTERED THUNDERSTORMS ARE WITHIN 75 NM OF
THE WAVE AXIS FROM 5N-8N.

TROPICAL WAVE OVER THE CENTRAL ATLC IS ALONG 50W S OF 16N MOVING
W NEAR 20 KT. WAVE IS AT THE LEADING EDGE OF DRY UPPER AIR AND
AFRICAN DUST...THUS ANY CONVECTION IS W OF THE WAVE AXIS. WAVE
SIGNATURE CURVATURE IS MASKED BEING AT THE BASE OF AN UPPER
LEVEL MID OCEANIC TROUGH.

TROPICAL WAVE IN THE E CARIBBEAN IS ALONG 63W/64W S OF 20N
MOVING W 15-20 KT. THE WAVE CONTINUES TO INTERACT WITH A STRONG
LOW LEVEL EASTERLY SURGE. WAVE IS EMBEDDED WITHIN DRY UPPER
AIR...THUS LIMITING CONVECTION ASSOCIATED WITH THIS WAVE TO
INLAND OVER SOUTH AMERICA.

...ITCZ...

ITCZ AXIS IS CENTERED ALONG 15N16W 10N43W 12N56W 10N65W.
CONVECTION IS LIMITED TO THE W TROPICAL ATLC. CLUSTERS OF
SCATTERED MODERATE/ISOLATED STRONG CONVECTION COVER THE AREA
FROM 2N-17N BETWEEN 44W-62W INCLUDING  THE WINDWARD ISLANDS.

...DISCUSSION...

GULF OF MEXICO...
MID/UPPER LEVEL RIDGE EXTENDS SW FROM AN UPPER HIGH OVER NW
ALABAMA ALONG THE COAST OF TEXAS INTO NE MEXICO. THE BROAD UPPER
HIGH ORIGINATING FROM HURRICANE EMILY COVERS THE SE GULF S OF
28N E OF 92W. THE MID-UPPER LEVEL TROUGH DIVIDES THE TWO UPPER
RIDGES AND HAS BECOME NARROW OVER THE PAST FEW HOURS.
WEAK/MODERATE SUBSIDENCE COVERS THE W GULF BUT IS GIVING WAY TO
THE TROPICAL MOISTURE ASSOCIATED WITH THE ADVANCEMENT OF
HURRICANE EMILY. CONDITIONS WILL DETERIORATE OVER THE S GULF AS
EMILY MOVES INTO THE GULF LATE TODAY AND CROSSES TO THE W GULF
COAST.

CARIBBEAN SEA...
HURRICANE EMILY CONTINUES TO DOMINATE THE WEATHER FOR THE NW
CARIBBEAN WITH AN OUTER RAINBAND EXTENDING FROM 19N78W TO OVER W
CUBA NEAR 22N81.5W. ELSEWHERE...UPPER LEVEL STRONG SUBSIDENCE
AND RELATIVELY DRY AIR ALOFT CONTINUES TO SPREAD WESTWARD OVER
MOST OF THE E AND CENTRAL CARIBBEAN COURTESY OF THE UPPER
MID-OCEANIC TROUGH EXTENDING ACROSS THE VIRGIN ISLANDS AND
PUERTO RICO TO THE ABC ISLANDS OFF THE COAST OF VENEZUELA. AN
MID/UPPER LEVEL RIDGE OVER THE E ATLC IS ADVECTING TROPICAL
MOISTURE N JUST E OF THE LESSER ANTILLES BRINGING SHOWERS/
THUNDERSTORMS TO THE WINDWARD ISLANDS. THE BROAD UPPER HIGH
ASSOCIATED WITH EMILY IS GENERATING SCATTERED SHOWERS/ISOLATED
THUNDERSTORMS ALONG THE COAST OF PANAMA AND COSTA RICA. THE NW
CARIBBEAN WILL BEGIN TO CLEAR AS EMILY MOVES INTO THE GULF OF
MEXICO TOADY.

ATLANTIC OCEAN...
MID/UPPER LEVEL RIDGE-TROUGH-RIDGE PATTERN CONTINUES OVER THE
ATLC WATERS WITH WEAK RIDGING OVER THE W ATLC W OF 70W...
MID-OCEANIC TROUGH OVER THE CENTRAL ATLC EXTENDING THROUGH
32N56W SW TO AN UPPER LOW NEAR 25N62W INTO THE CARIBBEAN...AND A
LARGE UPPER HIGH OVER THE E ATLC NEAR 23N40W. A SURFACE TROUGH
OVER THE CENTRAL/WESTERN ATLC EXTENDS FROM 21N62W NE TO
31N58W...REFLECTION OF THE UPPER LEVEL TROUGH. SCATTERED
SHOWERS/ISOLATED THUNDERSTORMS ARE WITHIN 400 NM NW OF A SURFACE
TROUGH AND SCATTERED MODERATE/STRONG CONVECTION IS SE OF THE
TROUGH WITHIN 75/90 NM OF LINE 17N59W-22N56W. A SURFACE RIDGE
EXTENDS TO THE W OF THE SURFACE TROUGH THROUGH BERMUDA WSW
ACROSS FLORIDA TO ALONG THE N GULF COAST NEAR TEXAS. THIS
ACTIVITY IS EXPECTED TO SLOWLY MOVE WESTWARD OVER THE NEXT FEW
DAYS. THE LARGE UPPER HIGH OVER THE CENTRAL ATLC COVERS THE AREA
FROM 15N-30N BETWEEN 30W AND THE UPPER TROUGH. OVER THE E
ATLC...THE UPPER MID-OCEANIC TROUGH IS MOSTLY N OF THE REGION
WITH A WEAK MID/UPPER TROUGH EXTENDING S THROUGH 32N21W TO
28N24W. BROAD MID/UPPER LEVEL RIDGE AXIS EXTENDS OFF AFRICA
ALONG 20N EXTENDING W TO 25W. THIS IS LIMITING CONVECTION OVER
THE E TROPICAL ATLC AND THE ITCZ. WEATHER OVER THE E ATLC IS
TRANQUIL WITH LOW LEVEL STRATIFORM CLOUDS.

$$
WALLACE




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