[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 251731
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT SAT JUN 25 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...

A COMPLEX LOW PRES SYSTEM IS LOCATED E OF THE N COAST OF FLORIDA
AND IS MOVING NNW NEAR 10 KT TOWARDS THE CAROLINA COAST. THE
MAIN CENTER OF LOW PRES...1011 MB...IS CENTERED ABOUT 270 NM E
OF JACKSONVILLE FLORIDA NEAR 30N76W AND IS CONNECTED BY A TROF
TO A SECONDARY 1012 MB LOW ABOUT 75 NM ESE OF JACKSONVILLE.
ANOTHER TROF EXTENDS SW OF THE SECONDARY LOW ACROSS CNTRL
FLORIDA INTO THE E GULF OF MEXICO MARKED BY A DISTINCT NE TO SW
WIND SHIFT. THE SYSTEM HAS A CLASSIC SUBTROPICAL CYCLONE
SIGNATURE...WITH THE CLOUD/RAIN SHIELD WRAPPING FROM THE E TO N
SIDE OF THE LOW AND DRY AIR BEING ADVECTED EWD OVER FLORIDA INTO
THE S SIDE OF THE SYSTEM. WINDS ON THE E SIDE OF THE SYSTEM HAVE
CONTINUED TO INCREASE...AND TROPICAL OR SUBTROPICAL CYCLONE
DEVELOPMENT IS POSSIBLE IN THE NEXT 24 HRS BEFORE THE SYSTEM
MOVES INLAND ALONG THE CAROLINA COAST. AN AIR FORCE
RECONNAISSANCE AIRCRAFT IS SCHEDULED TO INVESTIGATE THE SYSTEM
THIS AFTERNOON TO DETERMINE IF THIS HAS ALREADY OCCURRED.
SCATTERED MODERATE CONVECTION IS E OF THE BAHAMAS FROM 22N-32N
BETWEEN 69W-75W AND SCATTERED SHOWERS/TSTMS ARE FROM 31N-35N
BETWEEN 75W-85W MOVING INLAND ACROSS NORTH CAROLINA...SOUTH
CAROLINA...AND GEORGIA.

...TROPICAL WAVES...

EAST ATLANTIC TROPICAL WAVE ALONG 28W S OF 15N MOVING W 10-15
KT. THE WAVE IS EMBEDDED WITHIN A WEAK LOW-LEVEL FLOW REGIME AND
EASTERLY 30 KT WINDS AT 700 MB EMANATING OUT OF AFRICA ARE
GIVING THE WAVE A FORWARD TILT WITH HEIGHT. THE WAVE IS NOT
EASILY DEFINED IN SATELLITE IMAGERY...BUT UPPER AIR DATA FROM
SAL CAPE VERDE DID INDICATE A WAVE PASSAGE ABOUT 1-2 DAYS AGO.
THERE IS NO DEEP CONVECTION ASSOCIATED WITH THE WAVE.

CENTRAL ATLANTIC TROPICAL WAVE ALONG 41W S OF 14N MOVING W 15
KT. THIS WAVE IS ALSO NOT WELL-DEFINED IN SATELLITE IMAGERY AND
IS MARKED ONLY BY WIDELY SCATTERED SHOWERS/TSTMS TO THE E OF THE
AXIS...STRADDLING THE ITCZ.

TROPICAL WAVE NEAR THE WINDWARD ISLANDS ALONG 61W S OF 13N
MOVING W 15 KT. MUCH LIKE ITS TWO SUCCESSORS...THIS WAVE IS ALSO
VERY ILL-DEFINED IN SATELLITE IMAGERY. THE CAYENNE UPPER AIR
SOUNDING SHOWED A LOW-LEVEL PERTURBATION IN THE WIND FIELD BELOW
900 MB YESTERDAY...WHICH IS THE FEATURE WE HAVE BEEN
TRACKING...BUT THE DATA ALSO SUPPORTS A MORE ELEVATED WIND SHIFT
THIS MORNING. ONLY ISOLATED SHOWERS EXTEND FROM THE ORINOCO
DELTA NW TO TRINIDAD.

CENTRAL CARIBBEAN TROPICAL WAVE ALONG 76W S OF 19N MOVING W
10-15 KT. SLIGHT CURVATURE IN THE LOW-LEVEL CLOUD FIELD IS
OBSERVED EXTENDING FROM THE COLOMBIAN COAST NWD TO JAMAICA. A
LARGE CLUSTER OF SCATTERED MODERATE CONVECTION LIES OFF THE
COLOMBIA/W PANAMA COAST FROM 8N-11N BETWEEN 75W-79W. WIDELY
SCATTERED MODERATE CONVECTION ALSO EXTENDS FROM THE SRN
PENINSULA OF HAITI TO JAMAICA AND THE SE COAST OF CUBA.

WEST CARIBBEAN TROPICAL WAVE ALONG 85W S OF 17N MOVING W 10-15
KT...WITH A DETACHING SFC TROF OVER THE NW CARIBBEAN FROM
CENTRAL CUBA TO THE E TIP OF HONDURAS. THE MOST DEFINED
CIRCULATION ASSOCIATED WITH THE WAVE IS FOUND ALONG THE DETACHED
TROF...AND THIS IS WHERE THE LOW-LEVEL CONVERGENCE IS STRONG
ENOUGH FOR SCATTERED MODERATE CONVECTION FROM 14N-20N BETWEEN
79W-84W...INCLUDING OVER THE CAYMAN ISLANDS AND THE MOSQUITO
COAST OF HONDURAS/NICARAGUA. THE WAVE WILL BEGIN TO SPREAD HEAVY
SHOWERS/TSTMS THROUGH NRN PARTS OF CNTRL AMERICA ON SUN AND THEN
INTO THE BAY OF CAMPECHE ON MON.

...ITCZ...

ITCZ AXIS IS CENTERED ALONG 9N10W 6N19W 10N30W 3N52W 5N60W.
SCATTERED MODERATE/ISOLATED STRONG CONVECTION OFF THE COAST OF
AFRICA FROM 5N-13N BETWEEN 12W-23W. THE STRONGEST CLUSTER IS
CURRENTLY DEVELOPING ALONG THE COAST OF SRN SENEGAL AND
GUINEA-BISSAU. WIDELY SCATTERED SHOWERS/TSTMS FROM 4N-11N
BETWEEN 36W-42W. WIDELY SCATTERED SHOWERS/TSTMS NEAR GUYANA AND
SURINAME FROM 4N-9N BETWEEN 55W-61W.

...DISCUSSION...

GULF OF MEXICO...
THE MID/UPPER LEVEL LOW WHICH HAS BEEN MOVING OVER THE E GULF
AND FLORIDA DURING THE PAST FEW DAYS HAS EXPANDED AND
RETROGRADED TO THE NW TO THE S OF MOBILE ALABAMA NEAR 30N88W.
THE LOW HAS AN ALMOST ELLIPTICAL SHAPE AND A TROF AXIS STRETCHES
THRU THE LOW FROM ABOUT HOUSTON TEXAS TO N/CNTRL FLORIDA. DRY
AIR CONTINUES TO BE ADVECTED EWD ON THE S SIDE OF THE LOW AND
HAS SPREAD OVER MUCH OF THE NRN AND ERN GULF AND ALL OF
FLORIDA...WHICH IS SUPPRESSING DEEP CONVECTION OVER THE AREA.
THE SUBTROPICAL JET RUNS ACROSS CNTRL MEXICO TO THE W GULF AND S
FLORIDA WHICH IS BRINING IN HIGHER MOISTURE VALUES OVER THE BAY
OF CAMPECHE. ALONG WITH A SFC TROF LOCATED ALONG 19N94W
26N96W...THE MOISTURE IS SUPPORTING SCATTERED SHOWERS/TSTMS FROM
20N-26N BETWEEN 92W-97W. A SURGE OF MOISTURE IS EXPECTED TO
MOVE ACROSS FLORIDA...THE SE GULF...AND THE YUCATAN PENINSULA
BEHIND A STRONG TROPICAL WAVE BEGINNING LATE SUN AND SPREADING
TO THE W GULF BY THU AND FRI. THIS SHOULD SUPPORT CLUSTERS OF
SHOWERS/TSTMS MOVING FROM SE TO NW ACROSS THE GULF THRU THE WEEK.

CARIBBEAN...
AN UPPER LEVEL TROF REMAINS STUCK OVER THE NW CARIBBEAN WATERS
DUE TO THE UPPER LOW OVER THE GULF OF MEXICO...BUT THIS
CONTINUES TO KEEP THE WEATHER FROM BELIZE TO W CUBA RATHER NICE.
A BROAD UPPER LEVEL HIGH IS CENTERED NEAR WRN HONDURAS/GUATEMALA
WITH A RIDGE POKING EWD TO NEAR 16N77W...WHICH IS DISPLACING
CONVECTION ASSOCIATED WITH THE TRPCL WAVE ALONG 85W TO THE E
OVER THE CAYMAN ISLANDS. THE GFS INDICATES DRY AIR MOVING IN
FROM THE ATLC TO NEAR 72W...AND THIS IS CONFIRMED BY MOSTLY FAIR
SKIES WITH LITTLE CONVECTION OVER THE E/CNTRL PART OF THE BASIN.
THIS AREA OF DRY AIR WILL SPREAD OVER MOST OF THE CARIBBEAN OVER
THE NEXT COUPLE OF DAYS...WITH THE NEXT ROUND OF SHOWERS/TSTMS
EXPECTED TO MOVE OVER THE SRN LEEWARD/WINDWARD ISLANDS BEGINNING
LATE MON.

WEST ATLANTIC...
SEE SPECIAL FEATURES SECTION ABOVE FOR DISCUSSION ON COMPLEX LOW
CENTERED E OF FLORIDA...GEORGIA...AND THE CAROLINAS.

CENTRAL/EAST ATLANTIC...
A STRONG SHORTWAVE TROF IS DIGGING SWD OVER THE WATERS JUST N OF
THE AREA...AND EXTENDS S OF 32N ALONG 32N56W 28N61W. A LARGE
PATCH OF MID/UPPER LEVEL CLOUDS EXTENDS S OF THE SHORTWAVE FROM
26N-30N BETWEEN 53W-63W...BUT VISIBLE IMAGERY SUGGEST THAT
PROBABLY ON ISOLATED SHOWERS ARE EMBEDDED WITHIN THIS AREA.
FARTHER E...A NEARLY STATIONARY UPPER TROF IS ALONG 32N45W
25N43W AND IS COLLOCATED WITH A SFC TROF ALONG 30N48W
23N56W...PRODUCING ONLY ISOLATED SHOWERS/TSTMS FROM 23N-31N
BETWEEN 42W-50W. THE UPPER TROF EXTENDS SWWD INTO THE TROPICS
ALONG 20N47W TO NEAR TRINIDAD...AND A LARGE AREA OF DRY AIR IS
ROTATING WWD ON THE N SIDE OF THE TROF ADVECTING TOWARDS THE
LESSER ANTILLES. AN UPPER RIDGE LIES OVER THE E ATLC FROM ABOUT
THE COAST OF MAURITANIA ACROSS THE CAPE VERDES TO 11N40W...AND
THE SUBTROPICAL JET IS ALONG THE N PERIPHERY OF THE RIDGE
FEEDING INTO ANOTHER SHORTWAVE TROF THAT IS DROPPING DOWN TO THE
NW OF THE CANARY ISLANDS. DEEP CONVECTION IN THE TROPICS IS
PRIMARILY LIMITED TO E OF 25W...BUT SEVERAL CONVECTIVE CLUSTERS
CONTINUE TO ROLL OFF THE COAST AND SHOULD SPREAD W INTO THE
CNTRL ATLC DURING THE NEXT FEW DAYS.

$$
BERG


This weather bulletin was brought to you by:
www.nashvilleweather.net