[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 151213
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 AM EDT FRI JUL 15 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 1115 UTC.

...SPECIAL FEATURE...

HURRICANE EMILY IS CENTERED NEAR 14.1N 70.0W AT 15/1200 UTC...
MOVING WEST-NORTHWEST 20 MPH...32 KM/HR...AND THIS GENERAL
MOTION IS EXPECTED TO CONTINUE FOR THE NEXT 24 HOURS. MAXIMUM
SUSTAINED WINDS REMAIN NEAR 135 MPH...215 KM/HR...WITH HIGHER
GUSTS. THIS MAKES EMILY A CATEGORY FOUR HURRICANE ON THE
SAFFIR-SIMPSON HURRICANE SCALE. HOWEVER...SATELLITE IMAGES
SUGGEST THAT EMILY MAY HAVE WEAKENED A LITTLE DURING THE PAST
FEW HOURS. A RECONNAISSANCE PLANE WILL CHECK THE INTENSITY
SHORTLY. THE ESTIMATED MINIMUM CENTRAL PRESSURE IS 952 MB.
SEE 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 EYE IS NO LONGER
DISCERNIBLE ON INFRARED SATELLITE IMAGERY. THE CENTER OF
CIRCULATION IS MORE EVENLY EMBEDDED WITHIN THE CONVECTION
AND IS NOW A CAT 4 HURRICANE. NUMEROUS STRONG CONVECTION IS
WITHIN 45 NM OF THE CENTER IN ALL DIRECTIONS WITH SCATTERED
MODERATE/STRONG CONVECTION COVERING THE AREA FROM 12N-16N
BETWEEN 66W-71.5W INCLUDING THE ABC ISLANDS. UPPER LEVEL OUTFLOW
PATTERN IS NOW BEING SHEARED ON THE SOUTHERN SIDE OF THE SYSTEM.
THE FORECASTED TRACK WILL TAKE EMILY JUST S OF JAMAICA EARLY SAT
MORNING.

...TROPICAL WAVES...

EASTERN MOST TROPICAL WAVE IS ALONG 24W/25W S OF 17N MOVING W
NEAR 10-15 KT. MID/UPPER LEVEL ROTATION ASSOCIATED WITH THIS
WAVE IS NOT AS EVIDENT AS BEFORE WITH NO ASSOCIATED DEEP
CONVECTION.

CENTRAL TROPICAL WAVE IS FROM 24N42W THROUGH A 1011 MB LOW
CENTERED NEAR 16N44W TO 10N45W MOVING W NEAR 10 KT. WAVE
CONTINUES TO DISPLAY AN IMPRESSIVE SATELLITE SIGNATURE WITH AN
AREA OF SCATTERED MODERATE TO STRONG CONVECTION TO THE N OF THE
LOW FROM 16N-21.5N BETWEEN 40W-46W.

WEAK TROPICAL WAVE E OF THE LESSER ANTILLES IS ALONG 55W S OF
12N MOVING W NEAR 10 KT. SATELLITE SIGNATURE ASSOCIATED WITH
THIS WAVE APPEARS TO BE DOMINATED/MASKED BY THE MUCH LARGER AND
STRONGER CIRCULATION WITH THE WAVE JUST TO THE E. SCATTERED
MODERATE/ISOLATED STRONG CONVECTION IS WITHIN 75 NM OF 7N FROM
51W-57W.

TROPICAL WAVE OVER S MEXICO IS ALONG 96W S OF 19N MOVING W NEAR
10 KT. WAVE IS AT THE BASE OF A STRONG MID/UPPER LEVEL RIDGE
EXTENDING FROM OVER MEXICO INTO THE GULF OF MEXICO. THIS IS
PRODUCING MODERATE EASTERLY FLOW FORCING CONVECTION WESTWARD.
SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS INLAND OVER S
MEXICO AND WITHIN 60 NM ALONG THE COAST IN THE BAY OF CAMPECHE W
OF 94W.

...ITCZ...

ITCZ AXIS IS CENTERED ALONG 15N16W 10N26W 14N41W 10N49W 11N62W.
SCATTERED MODERATE/STRONG CONVECTION IS WITHIN 120 NM OF LINE
8N39W-2N44W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS
MOVING OFF AFRICA FROM 9N-14N E OF 19W. CLUSTERS OF SIMILAR
CONVECTION ARE WITHIN 120/150 NM OF THE AXIS FROM 27W-40W.

...DISCUSSION...

GULF OF MEXICO...
DEEP-LAYERED RIDGING DOMINATES THE GULF WITH A MID/UPPER LEVEL
AXIS NOW EXTENDING FROM CENTRAL MEXICO NE TO INLAND OVER THE SE
UNITED STATES AS THE MID/UPPER LOW OVER OKLAHOMA CONTINUES TO
DIG SE OVER TEXAS. STRONG CONVECTION THAT MOVED OFF TEXAS
EARLIER IS NOW AN AREA OF SCATTERED THUNDERSTORMS WITHIN 75 NM
ALONG THE COAST SE LOUISIANA NEAR 91W TO JUST S OF GALVESTON
TEXAS. THE SURFACE RIDGE AXIS REMAINS ALIGNED ALONG 26N. THIS
PATTERN WILL PRODUCE AN UNSETTLED/STORMY PATTERN OVER THE N AND
W GULF COAST FOR THE MOST OF TODAY. S OF THE RIDGE AXIS...
MODERATE EASTERLY FLOW WITH MODERATE SUBSIDENCE AND DRY AIR
ALOFT ARE MAINTAINING A TRANQUIL PATTERN EXCEPT IN THE AREA OF
THE TROPICAL WAVE. THIS DRY/STABLE PATTERN IS ENHANCED BY THE
MID/UPPER LEVEL TROUGH OVER THE BAHAMAS AND CUBA THAT HAS BECOME
A BROAD CUTOFF LOW AND WILL RETROGRADE WESTWARD REACHING THE
YUCATAN PENINSULA DURING THE WEEKEND.

CARIBBEAN SEA...
HURRICANE EMILY WILL CONTINUE TO DOMINATE THE WEATHER THROUGH
THE WEEKEND AS IT CONTINUES WNW UNDER THE INFLUENCE OF A STRONG
MID-LEVEL RIDGE OVER THE ATLC. ELSEWHERE...SCATTERED SHOWERS/
THUNDERSTORMS ARE OVER THE W CARIBBEAN W OF 74W TO THE YUCATAN
PENINSULA. STRONGEST THUNDERSTORMS ARE WITHIN 60 NM ALONG THE
COAST OF COLOMBIA FROM 9N-11N AND OVER THE S PORTION OF LAKE
MARACAIBO. THIS ACTIVITY IS ASSOCIATED WITH AN AREA OF UPPER
LEVEL DIFFLUENCE IN BETWEEN THE RIDGE EXTENDING FROM THE GULF S
OVER CENTRAL AMERICA AND THE UPPER LEVEL CUTOFF LOW OVER
NORTH-CENTRAL CUBA. THE UPPER LOW IS EXPECTED MOVE WESTWARD
THROUGH THE NW CARIBBEAN DURING THE NEXT 2 DAYS PRODUCING
CONFLUENCE AND DRY/STABLE CONDITIONS TO WEST AND DIFFLUENCE/
UNSTABLE CONDITIONS TO EAST.

ATLANTIC OCEAN...
MID/UPPER LEVEL HIGH IS OVER THE NW ATLC NEAR 31N74W WITH A
RIDGE AXIS EXTENDING N TO NEAR NEW ENGLAND. THE CUTOFF MID/UPPER
LEVEL LOW HAS FORMED ALONG THE N COAST OF CUBA NEAR 22N78W. THIS
IS TRIGGERING SCATTERED SHOWERS N OF CUBA AND HISPANIOLA TO OVER
THE BAHAMA ISLANDS. THIS UPPER CUTOFF LOW WILL RETROGRADE WEST
THROUGH THE NW CARIBBEAN INTO THE GULF OF MEXICO DURING THE
WEEKEND. BROAD MID/UPPER LEVEL LOW IN THE CENTRAL ATLC IS
CENTERED NEAR 31N48W WITH THE TROUGH COVERING THE AREA BETWEEN
44W-63W. SATELLITE IMAGERY INDICATES THAT APPRECIABLE MOISTURE
IS LIMITED IN THE CENTRAL ATLC WITH MODERATE SUBSIDENCE COVERING
THE AREA FROM 46W-57W. OVER THE E ATLC...WEAK MID/UPPER LEVEL
RIDGE CONTINUES TO COVER THE AREA E OF 40W. AT THE SURFACE...
SUBTROPICAL RIDGE EXTENDS FROM A WEAKENING 1029 MB HIGH NW OF
THE AZORES SW ALONG 32N54W ACROSS FLORIDA AND TO THE SE THROUGH
32N33W TO THE CANARY ISLANDS. MODERATE TO STRONG TRADES EXIST S
OF THE RIDGE TO THE ITCZ ALLOWING AREAS OF AFRICAN DUST TO MARCH
ACROSS ATLC TOWARD THE CARIBBEAN. AFRICAN DUST COVERS THE E ATLC
FROM 15N30N E OF 35W.

$$
WALLACE



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