[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 181158
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL.
805 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1045 UTC.

...SPECIAL FEATURE...

HURRICANE EMILY IS CENTERED OVER THE YUCATAN PENINSULA NEAR
21.2N 88.9W AT 1200 UTC OR ABOUT 50 MILES...80 KM...
EAST-NORTHEAST OF MERIDA MEXICO MOVING WNW AT 15 KT.
ESTIMATED MINIMUM CENTRAL PRESSURE IS 975 MB. MAXIMUM SUSTAINED
WIND SPEED IS 85 KT WITH GUSTS TO 110 KT MAKING EMILY A CATEGORY
TWO 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. THE
UPPER LEVEL OUTFLOW IS MOST IMPRESSIVE IN ALL BUT THE 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 32W/33W S OF 19N MOVING W 15
KT. LOW LEVEL CURVATURE IS OBSERVED BETWEEN 15N-20N ON VISIBLE
SATELLITE IMAGERY. SCATTERED THUNDERSTORMS ARE W OF THE WAVE
AXIS WITHIN A 60/75 NM RADIUS OF 7N34W.

TROPICAL WAVE OVER THE CENTRAL ATLC IS ALONG 51W/52W S OF 16N
MOVING W 15 KT. LOW AMPLITUDE WAVE IS AT THE LEADING EDGE OF DRY
UPPER AIR AND AFRICAN DUST. WAVE SIGNATURE CURVATURE IS MASKED
BEING UPPER LEVEL RIDGE NEAR THE BASE OF THE MID-OCEANIC TROUGH.

TROPICAL WAVE IN THE E CARIBBEAN IS ALONG 64W/65W S OF 18N
MOVING W 10-15 KT. THE WAVE CONTINUES TO INTERACT WITH A STRONG
LOW LEVEL EASTERLY SURGE AND AN UPPER LEVEL MID-OCEANIC TROUGH.
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 8N13W 7N21W 12N32W 12N54W 14N63W.
CONVECTION IS LIMITED TO THE W PORTION OF THE TROPICAL ATLC.
CLUSTERS OF SCATTERED MODERATE/STRONG CONVECTION ARE N OF THE
ITCZ AXIS TO 20N BETWEEN 52W-62W INCLUDING THE LESSER ANTILLES.
CLUSTERS OF SCATTERED MODERATE/ISOLATED STRONG CONVECTION ARE
FROM 2N-14N BETWEEN 45W-65W.

...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...
BUILDING N OVER THE E GULF S OF 30N E OF 93W. THE MID-UPPER
LEVEL TROUGH DIVIDES THE TWO UPPER RIDGES CONTINUES TO NARROW.
WEAK SUBSIDENCE COVERS THE W GULF BUT CONTINUES TO GIVE WAY TO
THE TROPICAL MOISTURE ASSOCIATED WITH THE ADVANCEMENT OF
HURRICANE EMILY. CONDITIONS WILL DETERIORATE OVER THE REMAINDER
OF THE S GULF AS EMILY MOVES INTO THE GULF TODAY AND CROSSES TO
THE W GULF COAST.

CARIBBEAN SEA...
HURRICANE EMILY IS NOW MOVING OUT OF THE CARIBBEAN WITH LINGER
OUTER RAINBANDS REMAINING OVER THE YUCATAN PENINSULA...YUCATAN
CHANNEL AND W CUBA. 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 PUERTO RICO AND
HISPANIOLA TO THE ABC ISLANDS AND NW VENEZUELA. AN MID/UPPER
LEVEL RIDGE OVER THE E ATLC IS ADVECTING TROPICAL MOISTURE N
ALONG THE LESSER ANTILLES BRINGING SHOWERS/THUNDERSTORMS TO THE
ISLANDS. THE BROAD UPPER HIGH ASSOCIATED WITH EMILY IS
GENERATING SCATTERED SHOWERS/ISOLATED THUNDERSTORMS ALONG THE
COAST OF PANAMA. THE NW CARIBBEAN WILL BEGIN TO CLEAR AS EMILY
MOVES INTO THE GULF OF MEXICO LATER TOADY.

ATLANTIC OCEAN...
MID/UPPER LEVEL RIDGE-TROUGH-RIDGE PATTERN CONTINUES OVER THE
ATLC WATERS WITH WEAK RIDGING OVER THE W ATLC W OF 72W...
MID-OCEANIC TROUGH OVER THE CENTRAL ATLC EXTENDING THROUGH
32N61W SW TO AN UPPER LOW NEAR 22N66W INTO THE CARIBBEAN...AND A
LARGE UPPER HIGH OVER THE E ATLC NEAR 24N45W. A SURFACE TROUGH
OVER THE CENTRAL/WESTERN ATLC EXTENDS FROM 21N63W NE TO
32N58W...REFLECTION OF THE UPPER LEVEL TROUGH. SCATTERED
SHOWERS/ISOLATED THUNDERSTORMS ARE NW OF A SURFACE TROUGH FROM
21N-29N TO 72W. A SURFACE RIDGE EXTENDS TO THE W OF THE SURFACE
TROUGH THROUGH BERMUDA W ALONG 30N TO NEAR TEXAS. THE SHOWER
ACTIVITY IS EXPECTED TO MOVE WESTWARD OVER THE NEXT FEW DAYS.
THE LARGE UPPER HIGH OVER THE CENTRAL ATLC COVERS THE AREA FROM
14N-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 28N22W. BROAD
MID/UPPER LEVEL RIDGE AXIS EXTENDS OFF AFRICA ALONG 18N
EXTENDING W TO 28W. 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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