[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 201122
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL.
805 AM EDT WED JUL 20 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 NEAR 24.8N 97.4W...OR ABOUT 35 MILES
E OF SAN FERNANDO MEXICO AND 75 MILES S OF BROWNSVILLE TEXAS...
AT 20/1000 UTC MOVING WNW 7 KT. MAXIMUM SUSTAINED WIND SPEED IS
110 KT WITH GUSTS TO 135 KT...MAKING EMILY A CATEGORY 3
HURRICANE ON THE SAFFIR-SIMPSON SCALE. ESTIMATED MINIMUM CENTRAL
PRESSURE REPORTED BY AIR FORCE RECONNAISSANCE IS 944 MB. 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 CENTER OF
THE EYE OF EMILY IS ALMOST ON THE COAST...THEREFORE IT DOES NOT
APPEAR THAT IT WILL MAKE CATEGORY 4 BEFORE COMPLETELY MAKING
LANDFALL. SCATTERED MODERATE/STRONG CONVECTION COVERS THE AREA
FROM 22N-27N W OF 94.5W TO INLAND OVER NE MEXICO AND EXTREME SE
TEXAS.

...TROPICAL WAVES...

E ATLC TROPICAL WAVE IS ALONG 38W/39W S OF 20N MOVING W NEAR 10
KT. CLEARLY DEFINED SHARP INVERTED-V SIGNATURE IN THE LOW LEVEL
CLOUDS IS OBSERVED ON VISIBLE SATELLITE IMAGERY. WAVE IS AT THE
LEADING EDGE OF A STRONG SURGE OF DRY SAHARAN AIR AND SUSPENDED
DUST WHICH IS MAKING THE ENVIRONMENT VERY UNFAVORABLE FOR ANY
DEEP CONVECTION.

TROPICAL WAVE E OF THE LESSER ANTILLES IS ALONG 59W S OF 15N
MOVING W 10-15 KT. WEAK WAVE IS BEING OVERSHADOWED BY THE STRONG
SE FLOW FEEDING INTO THE TROPICAL WAVE IN THE E CARIBBEAN.
SCATTERED SHOWERS ARE CONFINED S OF THE ITCZ AXIS.

E CARIBBEAN TROPICAL IS ALONG 70W/71W S OF 23N MOVING W 10-15
KT. WAVE CONTINUES TO INTERACT WITH A LARGE AND STRONG UPPER LOW
CURRENTLY LOCATED W OF JAMAICA. STRONG DIFFLUENCE E OF THE UPPER
LOW IS GENERATING SCATTERED MODERATE/STRONG CONVECTION MOSTLY E
OF THE WAVE AXIS FROM 16N-24N BETWEEN 61W-72W

...ITCZ...

ITCZ AXIS IS CENTERED ALONG 14N16W 9N28W 11N46W 11N63W. CLUSTERS
OF SCATTERED MODERATE CONVECTION ARE FROM 6N TO THE ITCZ AXIS
FROM 13W-18W AND 26W-37W. SCATTERED THUNDERSTORMS ARE WITHIN 90
NM S OF THE AXIS FROM 45W-50W AND FROM THE COAST OF SOUTH
AMERICA 13N W OF 53W-63W.

...DISCUSSION...

GULF OF MEXICO...
HURRICANE EMILY CONTINUES TO DOMINATE THE FOCUS OVER THE GULF OF
MEXICO...MAKING LANDFALL SHORTLY. THE OUTER RAINBANDS HAVE BEEN
ONSHORE FOR MOST OF THE NIGHT TIME HOURS. UPPER LEVEL OUTFLOW
FROM EMILY COVERS THE W GULF W OF 92W TO INLAND OVER TEXAS AND
MEXICO. ELSEWHERE...MID/UPPER RIDGE AXIS EXTENDS ACROSS THE SE
UNITED STATES ENE INTO THE W ATLC N OF THE REGION. THIS COUPLED
WITH THE UPPER TROUGH OVER THE W ATLC/CARIBBEAN IS GIVING THE E
GULF NE UPPER FLOW. DRY AIR HAS FILTERED ACROSS FLORIDA INTO THE
E GULF AND WILL CONTINUE WESTWARD ACROSS THE REMAINDER OF THE
GULF TODAY AND THU IN THE WAKE OF EMILY...BEFORE A TROPICAL WAVE
APPROACHES THE FLORIDA STRAITS AND S FLORIDA THU NIGHT WITH AN
INCREASED CHANCE OF SHOWERS/THUNDERSTORMS. LOW LEVEL SCATTERED
SHOWERS DOT THE E GULF E OF 86W.

CARIBBEAN...
CUT-OFF UPPER LOW IN THE W CARIBBEAN W OF JAMAICA NEAR 19N81W IS
INTERACTING WITH A TROPICAL WAVE PRODUCING A LARGE AREA OF
CONVECTION/SHOWER ACTIVITY N OF 16N BETWEEN 61W-72W. THE UPPER
LOW HAS ENOUGH DRY AIR TO PRODUCE FAIRLY BENIGN WEATHER OVER THE
CENTRAL CARIBBEAN N OF 17N FROM 74W-83W INCLUDING JAMAICA AND
PARTS OF CUBA. FARTHER SW...A TROPICAL SQUALL LINE WITH
SCATTERED/NUMEROUS STRONG CONVECTION CONTINUES TO EXPAND NOW
COVERING THE AREA SW OF LINE FROM COLOMBIA NEAR 11N74W TO N OF
HONDURAS NEAR 18N86W INCLUDING PANAMA AND COSTA RICA. DEEP
TROPICAL MOISTURE WILL REMAIN ESTABLISHED OVER THIS AREA TO
MAINTAIN SCATTERED CONVECTION FOR REMAINDER OF THE WORK WEEK.
OVER THE E CARIBBEAN...A MID/UPPER HIGH IS CENTERED NEAR 19N63W
WITH AN AMPLIFYING RIDGE AXIS EXTENDING NW TO 24N71W AND E TO
21N51W. THE DIFFLUENCE ASSOCIATED WITH THIS RIDGE IS ENHANCING
THE CONVECTION OVER THE NE CARIBBEAN...SEE TROPICAL WAVES ABOVE.

ATLANTIC...
MID/UPPER RIDGE THAT EXTENDS FROM OVER THE SE UNITED STATES INTO
THE NW ATLC GIVING THE AREA N OF THE BAHAMAS NE FLOW. THE
CUT-OFF LOW IN THE CARIBBEAN COVERS THE W ATLC S OF 27N W OF 71W
GENERATING SCATTERED SHOWERS/ISOLATED THUNDERSTORMS WITHIN 75 NM
OF LINE 30N77W TO THE COAST OF CUBA NEAR 22N79W. DIFFLUENCE
ASSOCIATED WITH MID/UPPER RIDGE EXTENDING FROM THE E CARIBBEAN
COVERS THE AREA S OF 24N FROM 61W-72W. OVER THE E ATLC...BROAD
MID/UPPER RIDGE COVERS THE AREA E OF 38W WITH THE UPPER HIGH
LOCATED JUST W OF THE CAPE VERDE ISLANDS NEAR 17N29W. THIS
UPPER FLOW IS RESPONSIBLE FOR THE LATEST SURGE OF AFRICAN DUST
OBSERVED ON VISIBLE SATELLITE IMAGERY FROM 20N-27N E OF 37W...
THUS SUPPRESSING CONVECTION OVER THE E ATLC AND LIMITING
VISIBILITIES. AT THE SURFACE...BROAD SUBTROPICAL RIDGE HAS BEEN
SPLIT WITH A SURFACE TROUGH IN THE CENTRAL ATLC FROM 32N43W SW
TO 23N52W. THE E RIDGE AXIS EXTENDS THROUGH 32N26W TO 25N42W AND
THE W RIDGE FROM 26N53W THROUGH A 1022 MB HIGH NEAR 30N63W TO
THE COAST OF SOUTH CAROLINA. IN ADDITION...A 1008 MB LOW IS
CENTERED OFF THE COAST OF MAURITANIA NEAR 19N19W AND A WEAK
SURFACE TROUGH EXTENDING SW TO S OF THE CAPE VERDE ISLANDS NEAR
14N24W. NO SHOWER ACTIVITY IS ASSOCIATED WITH THIS LOW/TROUGH
DUE TO THE CONCENTRATED DUST OVER THE AREA.

$$
WALLACE

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