[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 200003
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL.
805 PM EDT TUE JUL 19 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
2345 UTC.

...SPECIAL FEATURE...

HURRICANE EMILY IS CENTERED NEAR 24.4N 96.1W...OR ABOUT 85 NM E
OF BAHIA ALGODONES MEXICO AND 115 NM SE OF BROWNSVILLE TEXAS...
AT 20/0000 UTC MOVING WNW 10 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 945 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. EMILY HAS
STRENGTHENED RAPIDLY DURING THE DAY WITH THE CENTRAL PRESSURE
DROPPING BY ABOUT 30-35 MB OVER THE PAST 12 HRS. THE SATELLITE
REPRESENTATION HAS ALSO IMPROVED GREATLY NOW THAT RELATIVELY
LITTLE DRY AIR IS BEING ENTRAINED INTO THE SYSTEM BETWEEN THE
SPIRAL BANDS. A WELL-DEFINED BUT OBLONG EYE ALSO BECAME READILY
APPARENT DURING THE DAY...BUT THE CONVECTION WHICH HAS BEEN
REGENERATING IN THE EYEWALL HAS GIVEN IT A WOBBLING TRACK AS IT
MOVES W. EMILY IS EXPECTED TO MAKE LANDFALL ALONG THE COAST OF
NRN TAMAULIPAS STATE WITHIN THE NEXT 6-12 HRS POSSIBLY AS A
CATEGORY 4 STORM WITH WINDS TO 120 KT...OR 140 MPH. RESIDENTS
ALONG THE MEXICAN COAST BETWEEN LA PESCA AND BROWNSVILLE TX ARE
URGED TO SEEK SHELTER IMMEDIATELY BEFORE THE STRONGEST WINDS
BEGIN TO IMPACT THE AREA. NUMEROUS STRONG CONVECTION EXTENDS
WITHIN 100 NM E SEMICIRCLE AND 75 NM W SEMICIRCLE AND IS JUST
ABOUT TO REACH THE COAST OF EXTREME NE MEXICO...VERIFIED BY THE
BROWNSVILLE TX RADAR. THE COLDEST CLOUD TOPS ARE CURRENTLY
WITHIN THE S/SW PART OF THE EYEWALL AND THE HIGHEST RADAR
REFLECTIVITIES ARE WITHIN THE WRN EYEWALL. THE WESTERNMOST
SPIRAL BANDS HAVE ALREADY MOVED ONSHORE ACROSS NE MEXICO AND
COASTAL TEXAS WITH SCATTERED MODERATE/STRONG CONVECTION
ELSEWHERE FROM 21N-31N BETWEEN 92W-100W.

...TROPICAL WAVES...

EAST ATLANTIC TROPICAL WAVE ALONG 37W/38W S OF 19N MOVING W
10-15 KT. THE WAVE EXHIBITS A SHARP INVERTED-V SIGNATURE WITH A
LOW-LEVEL CIRCULATION CENTER NEAR 13N37.5W. THE WAVE IS BEING
OVERTAKEN BY A SURGE OF DRY SAHARAN AIR AND SUSPENDED DUST E OF
34W WHICH IS MAKING THE ENVIRONMENT UNFAVORABLE FOR DEEP
CONVECTION. HOWEVER...LOW STRATUS HAS BEEN INCREASING NEAR THE
AXIS AND LIGHT SHOWERS ARE POSSIBLE FROM 12N-22N BETWEEN 34W-44W.

TROPICAL WAVE LOCATED ABOUT 200-250 NM E OF THE LESSER ANTILLES
ALONG 57W S OF 17N MOVING W 10-15 KT. UNFORTUNATELY THIS WAVE IS
BEING OVERSHADOWED BY THE STRONG SELY FLOW FEEDING INTO THE
TRPCL WAVE OVER THE CNTRL CARIBBEAN...AS WELL AS A SURGE OF DRY
AIR/DUST SLIDING IN N OF A LINE FROM 10N50W TO THE NRN LEEWARD
ISLANDS. SCATTERED MODERATE CONVECTION IS LIMITED TO THE ITCZ.

EAST CARIBBEAN TROPICAL WAVE HAS MOVED OVER THE MONA PASSAGE
ALONG 67W/68W S OF 22N MOVING W 10-15 KT. THE WAVE HAS BEEN
INTERACTING WITH A LARGE AND STRONG UPPER LOW CURRENTLY LOCATED
NEAR JAMAICA WITH THE WLY FLOW ON THE UNDERSIDE OF THIS FEATURE
DECELERATING THE WAVE'S OVERALL MOVEMENT. SAN JUAN UPPER AIR
DATA CLEARLY SHOWS THE MID/UPPER PART OF THE LOW PASSING PUERTO
RICO EARLY ON MON...AND THE ACTUAL WAVE (BELOW 850 MB) PASSING
BEFORE 12Z THIS MORNING. THIS APPEARS TO MATCH WELL WITH
CURVATURE OBSERVED IN THE CLOUD/CONVECTIVE ELEMENTS IN VISIBLE
IMAGERY. STRONG DIFFLUENCE E OF THE UPPER LOW IS INDUCING
NUMEROUS MODERATE/STRONG CONVECTION FROM 16N-23N BETWEEN 61W-72W
SPREADING FROM ABOUT ST. KITTS AND BARBUDA WWD TO HISPANIOLA.
SAN JUAN RADAR CURRENTLY SHOWS MODERATE SHOWERS OVER PUERTO RICO
AND THE VIRGIN ISLANDS BUT A LINE OF HEAVY SHOWERS/TSTMS TO THE
S IS SPREADING N OVER ST. CROIX AND WILL BE OVER ST. THOMAS...
CULEBRA...VIEQUES...AND PUERTO RICO OVER THE NEXT SEVERAL HOURS.
HEAVY SHOWERS/TSTMS ARE EXPECTED TO CONTINUE MOVING W...
SPREADING OVER THE BAHAMAS...CUBA...JAMAICA...AND S FLORIDA WED
THROUGH FRI.

...ITCZ...

ITCZ AXIS IS CENTERED ALONG 19N15W 10N25W 14N36W...THEN ALONG
11N38W 9N50W 11N56W...AND THEN OVER NRN VENEZUELA WWD TO PANAMA
AND COSTA RICA. ISOLATED MODERATE CONVECTION 220 NM S OF THE
AXIS BETWEEN 20W-24W AND ALONG THE COAST OF GUINEA. SCATTERED
MODERATE WITHIN 100 NM OF THE AXIS BETWEEN 47W-60W. NUMEROUS
MODERATE/STRONG NEAR THE VENEZUELA/COLOMBIA BORDER FROM 8N-11.5N
BETWEEN 65W-75W. NUMEROUS MODERATE/STRONG NEAR PANAMA AND COSTA
RICA S OF 11N BETWEEN 78W-84W.

...DISCUSSION...

GULF OF MEXICO...
HURRICANE EMILY IS STRENGTHENING QUICKLY AS IT HEADS WEST
TOWARDS THE NW MEXICO/S TEXAS COAST AND IS EXPECTED TO MAKE
LANDFALL DURING THE EARLY MORNING HOURS ON WED. SEE SPECIAL
FEATURES ABOVE FOR FURTHER DISCUSSION. THE OUTFLOW CIRRUS
ASSOCIATED WITH EMILY IS RADIATING OUT ALMOST SYMMETRICALLY IN
ALL DIRECTIONS AND COVERS A GOOD PART OF THE WRN GULF...SE
TEXAS...AND CNTRL MEXICO. FARTHER E...THE UPPER LEVEL FLOW HAS
BECOME PRIMARILY N/NELY AS A STRONG MID/UPPER LOW NEAR JAMAICA
APPROACHES THE AREA. SOME DRY AIR ALOFT IS BEING DRAWN OVER THE
FAR SE GULF WITHIN THIS FLOW BUT DAYTIME CONVECTION WHICH FORMED
OVER FLORIDA HAS MOVED SW WITH SCATTERED MODERATE FROM 25N-30N
BETWEEN 82W-84W...STRETCHING FROM TAMPA BAY SWD TO NAPLES. DRIER
AIR WILL BEGIN TO FILTER IN ACROSS THE AREA ON WED AND THU IN
THE WAKE OF EMILY...BEFORE A TRPCL WAVE APPROACHES THE FLORIDA
STRAITS AND S FLORIDA THU NIGHT WITH AN INCREASED CHANCE OF
SHOWERS/TSTMS.

CARIBBEAN...
A LARGE MID/UPPER LOW LOCATED NEAR JAMAICA IS INTERACTING WITH A
TRPCL WAVE WHICH JUST CROSSED PUERTO RICO TO PRODUCE A LARGE
AREA OF STRONG CONVECTION N OF 16N BETWEEN 61W-71W...EXTENDING
FROM ABOUT GUADELOUPE WWD TO HISPANIOLA AND THE ADJACENT WATERS.
THE UPPER LOW ITSELF HAS ENVELOPED ENOUGH DRY AIR TO PRODUCE
FAIRLY BENIGN WEATHER BETWEEN 72W-80W WITH THE EXCEPTION OF
TSTMS WHICH HAVE POPPED OVER JAMAICA AND CUBA. FARTHER SW...A
TROPICAL SQUALL LINE HAS PROPAGATED W OF SAN ANDRES TOWARDS THE
NICARAGUAN COAST WITH SCATTERED MODERATE/STRONG CONVECTION S OF
15.5N BETWEEN 80W-85W. DEEP TROPICAL MOISTURE WILL REMAIN
ESTABLISHED OVER THIS AREA TO MAINTAIN SCATTERED CONVECTION FOR
MUCH OF THE WEEK. ELSEWHERE...ISOLATED SHOWERS/TSTMS ARE
TRAILING OVER THE WINDWARD ISLANDS ON THE LEE SIDE OF THE CNTRL
CARIBBEAN TRPCL WAVE...AND AHEAD OF THE WAVE LOCATED NEAR THE
GUYANA/SURINAME BORDER.

ATLANTIC...
A COUPLE OF WEAK SFC TROFS ARE LOCATED OVER THE W ATLC
WATERS...PRIMARILY AS SFC REFLECTIONS OF THE LARGE UPPER LOW
NEAR JAMAICA...AND ARE PRODUCING ISOLATED SHOWERS/TSTMS FROM THE
BAHAMAS NWD TO 29N BETWEEN 72W-80W. A MUCH LARGER AREA OF
CONVECTION IS SPREADING NWD FROM THE NRN LEEWARD ISLANDS AND
GREATER ANTILLES AS THE CARIBBEAN TRPCL WAVE AMPLIFIES...AND
THESE HEAVY RAINS ARE EXPECTED TO CREEP WWD OVER THE BAHAMAS
DURING THE NEXT 48 HRS. AN UPPER RIDGE IS ORIENTED ALONG 20N
OVER THE CNTRL ATLC WATERS WITH DRY AIR POSITIONED FROM 12N-24N
E OF 59W. THE DRY AIR EXTENDS TO THE SFC WITH VISIBLE IMAGERY
SHOWING SAHARAN DUST S OF 28N AND N OF A LINE FROM 10N46W TO
NEAR PUERTO RICO. THE LAST FEW IMAGES OF MET-8 DATA ALSO SHOWED
A SECOND MORE IMPRESSIVE SURGE OF DUST OVER THE E ATLC WATERS E
OF 36W BEHIND THE E ATLC TRPCL WAVE. IN ADDITION...A 1006 MB LOW
IS LOCATED ALONG THE COAST OF MAURITANIA NEAR 19N17W WHICH IS
PUMPING ADDITIONAL SAND/DUST OFF THE COAST OF WESTERN SAHARA.
SEVERAL STATIONS ALONG THE COAST OF W AFRICA HAVE REPORTED
BLOWING DUST/SAND WITH VISIBILITIES REDUCED TO AS LOW AS 5
MILES.

$$
BERG


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