[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 261758
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT TUE JUL 26 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1715 UTC.

...SPECIAL FEATURE...

TROPICAL STORM FRANKLIN IS CENTERED NEAR 32.3N 68.3W...OR ABOUT
180 NM W OF BERMUDA...AT 26/1800 UTC MOVING N AT 5 KT. MAXIMUM
SUSTAINED WIND SPEED IS 35 KT WITH GUSTS TO 45 KT. THE ESTIMATED
MINIMUM CENTRAL PRESSURE IS 1002 MB. SEE LATEST NHC FORECAST/
ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT1/WTNT21 KNHC AND THE
PUBLIC ADVISORY UNDER AWIPS/WMO HEADERS MIATCPAT1/WTNT31 KNHC
FOR MORE DETAILS. ALTHOUGH FRANKLIN HAS A NET MOVEMENT TO THE
N...THE EXPOSED LOW-LEVEL CENTER IS MEANDERING IN A CYCLOIDAL
MOTION W OF BERMUDA. WHAT CONVECTION IS LEFT NEAR FRANKLIN IS
DISPLACED UP TO 400-500 NM TO THE SE IN SCATTERED PATCHES.
WIDELY SCATTERED MODERATE FROM 26N-32N BETWEEN 55W-69W.

...TROPICAL WAVES...

CENTRAL ATLANTIC TROPICAL WAVE ALONG 39W/40W S OF 21N MOVING W
20 KT WITH A 1014 MB LOW ALONG THE AXIS NEAR 9N40W. A CONVECTIVE
BAND IS ORIENTED ALONG THE SRN PERIPHERY OF THE LOW...ALONG THE
ITCZ...BUT DRY AIR IS BEING ENTRAINED INTO THE TSTM ACTIVITY
FROM THE N. THE DRY AIR IS ASSOCIATED WITH A SIGNIFICANT AREA OF
DUST ALONG AND UP TO 700 NM AHEAD OF THE WAVE...AND THIS STABLE
ENVIRONMENT IS PRECLUDING MUCH CONVECTION N OF 10N. ISOLATED
TSTMS FROM 13N-16N BETWEEN 37W-40W. SEE ITCZ FOR RELATED
CONVECTION.

CENTRAL CARIBBEAN TROPICAL WAVE ALONG 72W S OF 16N MOVING W
15-20 KT. ALTHOUGH SATELLITE IMAGERY PROVIDES NO INDICATION OF
THE WAVE...CURACAO UPPER AIR DATA ACTUALLY SHOWS A LOW-LEVEL
PERTURBATION PASSING THE ISLAND OVERNIGHT SO THIS POSITION SEEMS
REASONABLE. SCATTERED MODERATE CONVECTION IS E OF THE WAVE OVER
NRN VENEZUELA.

TROPICAL WAVE OVER SRN MEXICO AND GUATEMALA ALONG 91W S OF 19N
MOVING W 10-15 KT. WEAK CYCLONIC CURVATURE IS NOTED S OF EL
SALVADOR WITH ONE CLUSTER OF TSTMS CURRENTLY MOVING FROM CNTRL
GUATEMALA INTO CHIAPAS STATE OF MEXICO.

...ITCZ...

ITCZ AXIS IS CENTERED ALONG 9N13W 16N38W...THEN ALONG 6N41W
10N55W...THEN ALONG 8N74W 10N83W 9N90W. A LARGE CLUSTER OF
NUMEROUS MODERATE/STRONG CONVECTION...LOCATED AHEAD OF THE NEXT
TRPCL WAVE...IS SLIDING OFF THE COASTS OF GUINEA AND SIERRA
LEONE FROM 5N-10N BETWEEN 13W-20W. NUMEROUS MODERATE SW OF THE
CAPE VERDES FROM 10N-14N BETWEEN 26W-30W. SCATTERED MODERATE
WITHIN 120 NM WITHIN THE AXIS BETWEEN 41W-50W. SCATTERED
MODERATE WITHIN 90 NM OF THE COAST OF ERN COSTA RICA/WRN PANAMA.

...DISCUSSION...

GULF OF MEXICO...
LIGHT AND VARIABLE WINDS OVER THE GULF ARE RESULTING FROM A WEAK
SFC RIDGE EXTENDING FROM CNTRL CUBA TO THE SW LOUISIANA COAST. A
SFC TROF...ORIGINATING FROM T.S. FRANKLIN...IS EMBEDDED IN THE
RIDGE AND CONTINUES ACROSS S FLORIDA THEN INTO THE E/CNTRL GULF
TO 28N90W. AREAS OF WEAK CONVERGENCE ARE PRODUCING ISOLATED
SHOWERS ALONG THIS TROF...SPECIFICALLY OFF THE COAST OF FT.
MYERS FL AND LOUISIANA. THE UPPER LEVELS ARE DOMINATED BY TWO
ANTICYCLONES NEAR THE TEXAS AND GEORGIA COASTS WHICH ARE
ADVECTED RELATIVELY DRY AIR SWWD OVER THE AREA. A SHARP INVERTED
TROF LIES ALONG THE MEXICAN COAST NEAR VERACRUZ AND IS MOVING
INLAND OVER S/CNTRL MEXICO ON THE S SIDE OF THE ANTICYCLONES.
OVERALL THOUGH...SKIES ARE RELATIVELY CLEAR WITH AN ABSENCE OF
ANY DEEP CONVECTION. STRANGELY ENOUGH FOR THIS TIME OF
YEAR...MOISTURE WILL BEGIN TO INCREASE NEAR THE N GULF COAST ON
THU WITH THE APPROACH OF A STRONG SUMMERTIME COLD FRONT...AND
COULD TRIGGER SCATTERED TSTMS INTO THE WEEKEND.

CARIBBEAN...
DRY AIR ALSO HAS ITS STRANGLEHOLD OVER THE CARIBBEAN WHERE THE
ABSENCE OF DEEP CONVECTION ALMOST SCREAMS AT YOU. THE AFRICAN
DUST PLUME APPEARS TO HAVE SPREAD OVER MOST OF THE AREA ALTHOUGH
CONCENTRATIONS HAVE REALLY THINNED OUT. HAZY SKIES ARE BEING
REPORTED AT MANY LOCATIONS AND VISIBILITIES HAVE BEEN REDUCED TO
3-5 MILES OVER THE DOMINICAN REPUBLIC...HAITI...AND JAMAICA. A
FEW TSTMS EXTEND FROM TRINIDAD SW INTO NRN VENEZUELA...AS WELL
AS NEAR THE COSTA RICA COAST...BUT IT DOESN'T APPEAR THAT ANY
GOOD MOISTURE SOURCE WILL MOVE ACROSS THE AREA ANY TIME SOON.
SLIGHTLY INCREASED PWAT VALUES MAY SPREAD OVER THE LESSER
ANTILLES ON WED WITH THE POSSIBILITY OF SHOWERS...BUT THIS
SHOULD NOT LAST LONG.

WEST/CENTRAL ATLANTIC...
T.S. FRANKLIN CONTINUES TO MEANDER W OF BERMUDA BUT HAS MANAGED
TO MOVE N OF 32N. A TRAILING SFC TROF EXTENDS FROM NEAR BERMUDA
SW TO 28N66W TO NEAR NASSAU BAHAMAS AND HAS TRIGGERED SCATTERED
MODERATE CONVECTION FROM 26N-32N BETWEEN 60W-70W...SOME OF WHICH
WILL OCCASIONALLY SPREAD OVER BERMUDA. A SMALL UPPER LOW IS
LOCATED OVER FRANKLIN NEAR 29N67W AND THE DIFFLUENCE TO ITS E IS
HELPING TO DISPLACE THE CONVECTION ASSOCIATED WITH THE T.S. TO
THE E. A SECOND BUT DRIER UPPER LOW IS LOCATED JUST E OF THE
TURKS AND CAICOS ISLANDS AND IS ENHANCING THE GORGEOUS WEATHER
OVER THE SRN BAHAMAS. FARTHER E...A SHARP UPPER TROF HAS
DEVELOPED ALONG 30N52W 18N55W AND IS INTERACTING WITH A SFC TROF
NE OF THE LESSER ANTILLES TO PRODUCE ISOLATED MODERATE
CONVECTION FROM 17N-29N BETWEEN 50W-59W.

EAST ATLANTIC...
STRONG UPPER LEVEL RIDGING IS ESTABLISHED ALONG 19N AND HAS
INCREASED THE DEEP EASTERLY FLOW OUT OF AFRICA AND ACROSS THE
ATLC WATERS. DUST CONTINUES TO SPREAD OVER THIS AREA AS WELL AND
HAS STABILIZED THE ENVIRONMENT SO THAT DEEP CONVECTION IS ALL
LIMITED S OF 15N. ASIDE FROM THE TSTMS ASSOCIATED WITH THE TRPCL
WAVE ALONG 40W AND THE NEW WAVE SOON TO MOVE OFF THE AFRICAN
COAST...A CLUSTER OF SCATTERED MODERATE/STRONG CONVECTION IS
FLARING UP SW OF THE CAPE VERDE DUE ALONG THE ITCZ. FARTHER
N...A DEEP UPPER TROF LOCATED W OF PORTUGAL ALONG 16W IS DRIVING
A COLD FRONT SWD WHICH IS CLIPPING THE AREA ALONG 32N18W 30N25W
32N31W. ONLY SCATTERED CLOUDS AND A FEW ISOLATED SHOWERS ARE
LOCATED ALONG THIS FRONT.

$$
BERG




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