[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 030544
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 AM EDT SAT SEP 03 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
0345 UTC.

...SPECIAL FEATURE...

TROPICAL STORM MARIA CENTERED NEAR 22.4N 51.4W...OR ABOUT 700 NM
ENE OF THE NORTHERN LEEWARD ISLANDS...AT 03/0300 UTC MOVING NW
10 KT. MAXIMUM SUSTAINED WINDS ARE 45 KT WITH GUSTS TO 55 KT.
ESTIMATED MINIMUM CENTRAL PRESSURE 1001 MB. SEE LATEST NHC
FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT4/WTNT24 KNHC
FOR MORE DETAILS.  COPIOUS AMOUNTS OF HIGH CLOUDS HAVE MADE THE
LOW-LEVEL CENTER OF MARIA DIFFICULT TO LOCATE BUT IT APPEARS TO
BE SOUTH OF A BURST OF CONVECTION NEAR 23.5N51W.  AN UPPER HIGH
IS LOCATED NEAR THE CYCLONE WITH RELATIVELY LIGHT SHEAR.  MARIA
COULD BECOME THE SEASON'S 5TH HURRICANE IN A COUPLE OF DAYS WITH
FORECAST LOW SHEAR AND WARM WATERS IN ITS PATH.

...TROPICAL WAVES...

E ATLC WAVE ALONG 25W S OF 18N MOVING W 10-15 KT.  THIS IS NOT A
WELL-DEFINED WAVE WITH ONLY WEAK TURNING NOTED ON NIGHT VIS
IMAGES.  ISOLATED TSTMS FROM 11N-15N BETWEEN 21W-26W.

CENTRAL ATLC TROPICAL WAVE ADDED ALONG 38W S OF 16N MOVING W
10-15 KT WITH A 1010 MB LOW ALONG THE WAVE NEAR 10N.  THIS
SYSTEM WAS CONSIDERED A SUSPECT AREA FOR DEVELOPMENT YESTERDAY
BUT HAS FALLEN APART RECENTLY.  THERE ARE STILL ISOLATED TSTMS
FROM 10N-14N BETWEEN 38W-40W ASSOCIATED WITH THE WAVE.  MOST
MODELS NOW SUGGEST LITTLE CHANCE FOR TROPICAL CYCLONE
DEVELOPMENT IN THE SHORT-TERM THOUGH THE SYSTEM WILL HAVE TO BE
WATCHED AS IT APPROACHED THE LESSER ANTILLES NEXT WEEK.

E CARIBBEAN WAVE ALONG 67W/68W S OF 14N MOVING W 10-15 KT.
CURRENT POSITION IS BASED ON EXTRAPOLATION WITH LITTLE IN THE
WAY OF SATELLITE TO HELP FIND THE WAVE.  THE ENVIRONMENT IS DRY
AND CONVECTION-FREE BUT A FEW TSTMS OVER LAND COULD BE
ASSOCIATED WITH THIS SYSTEM.

TROPICAL WAVE OVER SOUTHERN MEXICO ALONG 94W S OF 18N MOVING W
15-20 KT. THE NRN PORTION OF THE WAVE HELPED FIRE SCATTERED
MODERATE TSTMS WITHIN 75 NM OF 17N93.5W NEAR AND TO THE N OF THE
GULF OF TEHAUNTEPEC.

...ITCZ...

ITCZ AXIS IS CENTERED ALONG 12N15W 13N25W 14N34W 7N45W.  THE
ITCZ IS NOT WELL-DEFINED ANYWHERE ESPECIALLY W OF 45W.  WIDELY
SCATTERED MODERATE CONVECTION IS FROM 7N-12N BETWEEN 42W-46W.
SIMILAR CONVECTION WITHIN 45 NM OF LINE 7N10W 7N20W.

...DISCUSSION...

GULF OF MEXICO...
MID/UPPER LEVEL RIDGING LIES FROM NE FLORIDA TO SE TEXAS ACROSS
THE NRN GULF COAST WITH AN UPPER HIGH CENTERED JUST S OF
LOUISIANA NEAR 28N93W. DEEP TROPICAL MOISTURE IS LOCATED S OF
THE RIDGE AXIS AND EARLIER CAUSED PLENTY OF TSTMS WHICH HAVE
SINCE DISSIPATED.  SURFACE TROUGH STRETCHES ACROSS CENTRAL
FLORIDA FROM JUST N OF PALM BEACH WWD TO 27N88W... WHICH SEEMS
TO BE FOCUSING ISOLATED TSTMS OVER GULF WATERS WITHIN 60 NM OF
THE TROUGH AXIS.  A LITTLE DRIER AIR IS TRYING TO MAKE ITS WAY
DOWN THE FLORIDA PENINSULA THOUGH IT REMAINS MOSTLY IN NE
FLORIDA.  ENOUGH MOISTURE WILL LINGER FROM S FLORIDA TO THE BAY
OF CAMPECHE FOR TSTMS TO DEVELOP THROUGHOUT THE SRN GULF.
HOWEVER ALL IN ALL THE AREA WILL BE DRIER THAN AVERAGE WITH A
1022 MB HIGH OVER MISSOURI KEEPING CONTINENTAL AIR MOVING
SOUTHWARD OVER THE GULF... WITH THE EXCEPTIONS BEING S FLORIDA
AND S TEXAS.

CARIBBEAN...
ELONGATED UPPER LOW IS LOCATED OVER THE NW CARIBBEAN EXTENDING
FROM E CUBA TO THE GULF OF HONDURAS.  A FEW SHOWERS ARE BENEATH
THE LOW... OTHERWISE DIURNAL TSTMS WERE TYPICAL IN YUCATAN AND W
CUBA.  AN UPPER LEVEL HIGH IS CENTERED NEAR NE NICARAGUA WITH A
LARGE AREA OF DIFFLUENCE ALOFT CENTERED OVER THE SW CARIBBEAN
WHERE THE FLOW DIVERGES BETWEEN THE HIGH AND LOW.  EARLIER
STRONG CONVECTION HAS WEAKENED WITH ISOLATED MODERATE CONVECTION
S OF SAN ANDRES W OF 76W.   ELSEWHERE...DRY AIR AND CLEAR
CONDITIONS EXTEND E OF 76W WITH ANOTHER UPPER HIGH CENTERED S OF
HISPANIOLA NEAR 16N71W. THE DRY AIR MASS WILL SLOWLY EXPAND OVER
THE ENTIRE CARIBBEAN OVER THE WEEKEND WITH THE POSSIBILITY OF
INCREASED MOISTURE AND SOME SHOWERS MOVING ACROSS THE WINDWARD
ISLANDS LATE MON.  THE SW AND NW CARIBBEAN SHOULD SEE THE BULK
OF THE PRECIPITATION THIS WEEKEND AS THE DRY AIR LIMITS TSTMS IN
THE CENTRAL/E CARIBBEAN.

W ATLANTIC...
A COMPLEX SCENARIO CONTINUES OVER THE W ATLC. THREE DISTINCT
SURFACE LOWS ARE OBSERVED IN SATELLITE IMAGERY AND THE ISOBARIC
ANALYSIS...A 1011 MB LOW E OF JACKSONVILLE NEAR 30N77W...1010 MB
LOW NEAR 28N70W...AND A 1011 MB LOW S OF BERMUDA NEAR 31N65W. A
WEAK STATIONARY FRONT WHICH MOVED OFF THE U.S. EAST COAST
CONNECTS TO THE WESTERNMOST LOW...AND THEN A TROUGH EXTENDS SW
OF THE LOW INLAND OVER S-CENTRAL FLORIDA. THE TWO OTHER LOWS LIE
AHEAD OF THE FRONT...WITH A TROUGH EXTENDING FROM THE LOW NEAR
BERMUDA TO 25N66W. AN UPPER LOW IS LOCATED WITHIN THE SAME
GENERAL REGION NEAR 31N61W WITH A TROUGH SW TO 21N69W AND AN
AREA OF UPPER DIFFLUENCE IS PRODUCING ISOLATED MODERATE
CONVECTION WITHIN 75 NM OF 25.5N67W.  LITTLE MOVEMENT IS
FORECAST WITH SOME CHANCE OF TROPICAL CYCLONE GENESIS POSSIBLE
IF UPPER RIDGING DEVELOPS OVER THE AREA LIKE SOME COMPUTER
MODELS ARE SUGGESTING.

E & CENTRAL ATLANTIC...
TROPICAL STORM MARIA IS MOVING NWWD OVER THE CENTRAL ATLC WATERS
UNDER THE SRN FLANK OF AN UPPER HIGH NEAR 27N52W.  IT SEEMS TO
HAVE LEFT THE INFLUENCE OF AN UPPER LOW NEAR 19N57W AND COULD
EVENTUALLY BECOME A HURRICANE AS IT ENTERS HIGHER LATITUDES.
ISOLATED TSTMS ARE WITHIN 90 NM OF THE UPPER LOW WITH PLENTY OF
UPPER INSTABILITY OVER WARM WATERS.   A RATHER DEEP UPPER TROUGH
IS DIGGING INTO THE AREA FROM A LOW NEAR 34N30W WITH A TROUGH SW
TO 24N40W.  AN EARLY-SEASON COLD FRONT IS INTO THE AREA ALONG
31N30W TO 27N37W.   SCATTERED SHOWERS/TSTMS LIE AHEAD OF THE
FRONT WITHIN 60 NM.  AHEAD OF THIS TROUGH THERE IS ANOTHER
TROUGH... RUNNING FORM 24N24W TO 17N31W.. MUCH FARTHER S THAN
AVERAGE FOR EARLY SEPT.  THIS IS PROBABLY WHY ALL THE SYSTEMS IN
THE DEEP TROPICS HAVE BEEN STRUGGLING E OF THE LESSER ANTILLES.
TYPICAL UPPER RIDGING IS SPLIT INTO TWO PARTS OVER THE DEEP
TROPICS... ONE HIGH NEAR 17N46W WITH ANOTHER OVER W AFRICA.  THE
PRESSURE GRADIENT IS VERY WEAK OVER THE DEEP TROPICS EXCEPT NEAR
MARIA... LEAVING LIGHT WINDS AND RELATIVELY CALM SEAS.

$$
BLAKE

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