[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 020618
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 AM EDT SAT JUL 02 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 0000 UTC SURFACE ANALYSIS AND
SATELLITE IMAGERY THROUGH 0515 UTC.

...TROPICAL WAVES...

EAST ATLANTIC TROPICAL WAVE ALONG 30W S OF 15N MOVING W 15 KT.
THE SAL UPPER AIR SOUNDING IS MOSTLY INCONCLUSIVE REGARDING WAVE
PASSAGE...BUT THE DAKAR TIMESECTION SUGGESTS A BACKWARD-LEANING
STRUCTURE GIVEN THAT THE LOW-LEVEL PERTURBATIONS PRECEDED THE
MID-LEVEL PERTURBATION BY 18-24 HRS. A WEAK CIRCULATION IS NOTED
WITHIN THE ITCZ NEAR 29W...BUT WHAT IS MORE IMPRESSIVE IS THE
WIDESPREAD DUST OUTBREAK MOVING OFF THE AFRICAN COAST BEHIND THE
WAVE FROM 9N-26N.

LARGE AMPLITUDE CENTRAL ATLANTIC TROPICAL WAVE TILTED ALONG
7N46W 15N47W 22N45W MOVING W 10-15 KT. ONE 1012 MB LOW PRESSURE
CENTER HAS BEEN LEFT BEHIND BY THE WESTBOUND WAVE. THE LOW
CENTER IS NEAR 9N43W. THE FORMATION OF THE LOW IS NOT YET
INDICATIVE OF TROPICAL DEVELOPMENT SINCE THE CIRCULATION IS
STILL QUITE BROAD...THERE IS ESSENTIALLY NO DEEP CONVECTION NEAR
THE CENTER...AND A FEW OTHER VORT MAXIMA ARE STILL BEING
OBSERVED PRIMARILY WITHIN THE TRAILING ITCZ. THE GFS AND UKMET
MODELS INTERMITTENTLY PRESCRIBE TO A LOW ALONG THE WAVE AS IT
NEARS THE LESSER ANTILLES BUT NONE OF THE GUIDANCE LATCHES ON TO
A CONSOLIDATED SFC CIRCULATION. MOISTURE ASSOCIATED WITH THE
WAVE WILL BEGIN TO SPREAD OVER THE LESSER ANTILLES SUN EVENING
WITH EPISODES OF SHOWERS/TSTMS LIKELY FOR MUCH OF NEXT WEEK.
ISOLATED SHOWERS/TSTMS FROM 4N-14N BETWEEN 36W-46W.

WEST CARIBBEAN TROPICAL WAVE FROM CUBA NEAR 22N77W TO 15N81W TO
6N81W IN THE EASTERN PACIFIC OCEAN. AN UPPER LOW CENTERED ALONG
THE SRN COAST OF CUBA IS IMPEDING THE FORWARD PROGRESS OF THE
NRN PART OF THE WAVE AND HAS LED TO A STRONG SW/NE TILT. AN
UPPER RIDGE STRADDLES THE WAVE AXIS FROM THE YUCATAN CHANNEL
TO S OF HAITI AND IS PROVIDING A DIFFLUENT ENVIRONMENT FOR
SCATTERED MODERATE TO ISOLATED STRONG SHOWERS AND THUNDERSTORMS
MOSTLY IN THE CARIBBEAN WATERS...FROM 15N TO 20N BETWEEN 74W AND
81W. THE WAVE IS EXPECTED TO EXPAND TO THE N AND EXTEND FROM THE
YUCATAN TO THE SE GULF BY SUN AFTERNOON. SHOWERS/TSTMS ARE
LIKELY OVER THE W CARIBBEAN ON SAT SPREADING OVER W CUBA...THE
SE GULF...AND YUCATAN ON SUN...THEN INTO THE CNTRL GULF ON MON.
THIS PATTERN IS QUITE SIMILAR TO THE PRECURSOR TO TROPICAL STORM
BRET...SO THIS AREA WILL NEED TO BE MONITORED OVER THE NEXT
SEVERAL DAYS.

...ITCZ...

ITCZ 13N16W 11N23W 11N28W...8N31W 10N38W 11N45W...9N50W 7N57W
11N66W. SCATTERED MODERATE TO ISOLATED STRONG SHOWERS AND
THUNDERSTORMS FROM 8N TO 10N BETWEEN THE COAST AT 13W AND 18W...
FROM 8N TO 10N BETWEEN 24W AND 26W...FROM 8N TO 10N BETWEEN 30W
AND 32W...FROM 12N TO 14N BETWEEN 39W AND 41W...AND FROM 8N TO
9N BETWEEN 53W AND 55W.

...DISCUSSION...

GULF OF MEXICO...
A HIGH PRES SFC RIDGE AND WIDESPREAD MID/UPPER LEVEL SUBSIDENCE
ARE BOTH LEADING TO MAINLY CLEAR SKIES OVER THE SRN 3/4 OF THE
GULF REGION. AN INVERTED MID-LEVEL TROF EXTENDS FROM THE BAY OF
CAMPECHE TO JUST S OF LOUISIANA AND IS MOVING W...BEGINNING TO
SOMEWHAT DRAG IN INCREASED MOISTURE FROM THE EAST. INCREASED
MOISTURE WILL BEGIN TO MOVE INTO THE SE GULF ON SUN BEHIND A
TRPCL WAVE...SPREADING SHOWERS/TSTMS TOWARDS THE N GULF AND
MEXICAN COASTS BY TUE AND WED.

CARIBBEAN...
WEST CARIBBEAN TROPICAL WAVE FROM CUBA NEAR 22N77W TO 15N81W
TO 6N81W IN THE EASTERN PACIFIC OCEAN. SCATTERED MODERATE TO
ISOLATED STRONG SHOWERS AND THUNDERSTORMS MOSTLY IN THE
CARIBBEAN WATERS...FROM 15N TO 20N BETWEEN 74W AND 81W.
MIDDLE TO UPPER LEVEL DRY AIR IS NORTH OF 14N70W 12N65W
10N60W EAST OF 70W. IT IS LIKELY CHANGE BY SUN AFTERNOON AS
MOISTURE MOVES IN FROM THE ATLC AND THE AREA OF DRY AIR SHIFTS
WWD TO THE W/CNTRL CARIBBEAN.

ATLANTIC...
ONE WEAK SFC TROF OVER THE W ATLC WATERS IS EMBEDDED BENEATH THE
MOISTURE PLUME ASSOCIATED WITH THE SUBTROPICAL JET. A WEAKNESS
IN THE SURFACE TO LOW LEVEL PRESSURE FIELD STILL REMAINS IN THE
ATMOSPHERE ENOUGH...NEAR A 31N58W 27N63W...SCATTERED MODERATE TO
STRONG SHOWERS AND THUNDERSTORMS FROM 27N TO 28N BETWEEN 62W AND
63W. THE JET DIPS SWD OVER THE CNTRL ATLC AROUND A MID/UPPER
LEVEL CUT-OFF LOW NEAR 28N51W WHICH IS CAUSING AN AREA OF WIDELY
SCATTERED SHOWERS FROM 27N-31N BETWEEN 45W-52W. A SECOND UPPER
LOW IS DEPARTING THE AREA NEAR 33N23W MOVING E TOWARDS SPAIN AND
PORTUGAL WHILE A REMNANT UPPER LEVEL SHEAR AXIS EXTENDS SW OF
THE CANARY ISLANDS TO 15N40W. AN UPPER RIDGE EXTENDS W OF AFRICA
ACROSS THE CAPE VERDES ALONG 16N WITH DEEP-LAYERED EASTERLIES
PUSHED S OF 12N. THE LOW-LEVELS REMAIN DRY AND STABLE OVER THE E
ATLC...AND A NEW SAHARAN DUST PLUME HAS SPREAD WWD ACROSS THE
CAPE VERDES FROM 10N-24N E OF 30W.

$$
MT



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