[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 031823
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 PM 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1745 UTC.

...SPECIAL FEATURE...

THE CENTER OF TROPICAL STORM MARIA AT 03/1500 UTC WAS NEAR
25.1N 53.7W ABOUT 770 MILES/1235 KM NORTHEAST OF THE NORTHERN
LEEWARD ISLANDS...AND ABOUT 835 MILES/1345 KM SOUTHEAST OF
BERMUDA. IT WAS MOVING NORTHWEST 13 KT. THE ESTIMATED MINIMUM
CENTRAL PRESSURE WAS 997 MB. THE MAXIMUM SUSTAINED WIND SPEEDS
WERE 50 KT WITH GUSTS TO 60 KT. PLEASE REFER TO THE LATEST NHC
FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT4/WTNT24 KNHC
AND THE PUBLIC ADVISORY UNDER AWIPS/WMO HEADERS MIATCPAT4/
WTNT34 KNHC FOR MORE DETAILS. MARIA GRADUALLY HAS BECOME BETTER
ORGANIZED...BOTH IN THE CLOUD PATTERN AND WITH THE FACT THAT
THE CENTER IS SURROUNDED BY MORE DEEP CONVECTIVE ACTIVITY.
NUMEROUS STRONG THUNDERSTORMS WERE FOUND FROM 23.5N TO 26N
BETWEEN 52W AND 55.5W AT 03/1245 UTC. THE SITUATION IS A BIT
DIFFERENT FIVE HOURS LATER. NUMEROUS STRONG THUNDERSTORMS ARE
FOUND FROM 24.5N TO 26N BETWEEN 54W AND 56W. A CYCLONICALLY
CURVED CONVECTIVE BAND IS EAST OF THE CENTER WITHIN 40 TO 50 NM
ON EITHER SIDE OF 27N53W 25N52W 22N54W. MARIA LOOKS BETTER IN
THE SATELLITE IMAGERY AND THERE WERE SOME 50 KT QUIKSCAT WINDS.
MARIA IS EXPECTED TO CONTINUE OVER WARM WATERS FOR A COUPLE OF
DAYS AND WITHIN A LOW SHEAR ENVIRONMENT...AWAY FROM THE
UPPER-LOW...AND STRENGTHENING IS INDICATED. MARIA MAY
BECOME A HURRICANE IN 24 HOURS OR SO.

...TROPICAL WAVES...

EASTERN ATLANTIC OCEAN TROPICAL WAVE ALONG 26W/27W SOUTH OF 18N
MOVING WEST 10-15 KT. THIS IS NOT A WELL-DEFINED WAVE WITH LITTLE
TO NO ASSOCIATED DEEP CONVECTIVE ACTIVITY.

CENTRAL ATLC TROPICAL WAVE ALONG 41W/42W SOUTH OF 18N MOVING
WEST 10 TO 15 KT. BROAD LOW PRESSURE IS ALONG THE WAVE NEAR
12N. THIS SYSTEM WAS CONSIDERED A SUSPECT AREA FOR POSSIBLE
TROPICAL CYCLONE DEVELOPMENT YESTERDAY...BUT NOW DEVELOPMENT
IS NOT BEING ANTICIPATED. ISOLATED MODERATE SHOWERS FROM
12N TO 15N BETWEEN 40W AND 44W.

EASTERN CARIBBEAN SEA WAVE ALONG 70W/71W SOUTH OF 15N MOVING
WEST 10-15 KT. THERE IS SLIGHT CYCLONIC TURNING IN THE LOW CLOUD
FIELD...IF ANY...WITH THIS WAVE. THE ENVIRONMENT NEAR THE WAVE
IS DRY AND CONVECTION-FREE BUT A FEW TSTMS OVER LAND COULD BE
ASSOCIATED WITH THIS SYSTEM.

TROPICAL WAVE OVER SOUTHERN MEXICO ALONG 96W/97W SOUTH OF 18N
MOVING WEST 15-20 KT. THE SHOWERS AND THUNDERSTORMS IN THE
WESTERN GULF OF MEXICO SOUTH OF 25N UP AGAINST THE MEXICO COAST
MAY BE MORE RELATED TO THE WESTERN END A NORTHWEST-SOUTHEAST
ORIENTED MIDDLE TO UPPER LEVEL TROUGH...WHICH RUNS FROM THE
CARIBBEAN SEA NORTHWESTWARD...THAN TO THIS WAVE.

...THE ITCZ...

ITCZ 14N17W 14N25W...13N27W 11N39W...10N43W 7N50W 5N55W.
ISOLATED TO WIDELY SCATTERED MODERATE SHOWERS TO LOCALLY
STRONG THUNDERSTORMS FROM 2N TO 12N BETWEEN 10W AND 30W.
SCATTERED MODERATE SHOWERS TO ISOLATED STRONG THUNDERSTORMS
FROM 7N TO 9N BETWEEN 46W AND 47W. ISOLATED MODERATE SHOWERS
ELSEWHERE FROM 6N TO 10N BETWEEN 45W AND 50W.

...DISCUSSION...

THE 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 LAKE
CHARLES LOUISIANA NEAR 28N93W. DEEP TROPICAL MOISTURE IS LOCATED
SOUTH OF THE RIDGE. A SURFACE TROUGH STARTS OUT IN THE WESTERN
ATLANTIC WATERS ALONG 26N AND REACHES THE SOUTHEASTERN FLORIDA
COAST...AND THEN BECOMES WEAKER AND A FAINT HINT OF THIS TROUGH
CONTINUES WESTWARD TO THE UPPER TEXAS COAST. ISOLATED MODERATE
SHOWERS ARE FOUND FROM 24N TO 26N BETWEEN SOUTH FLORIDA AND 95W.
SCATTERED MODERATE TO ISOLATED STRONG SHOWERS AND THUNDERSTORMS
ARE FOUND FROM 26N NORTHWARD TO THE TEXAS COAST BETWEEN 94W AND
96W. SCATTERED MODERATE TO ISOLATED STRONG SOUTH OF 25N BETWEEN
95W AND THE MEXICO COAST MAY BE MORE RELATED TO THE WESTERN END
OF A CARIBBEAN SEA-TO-GULF OF MEXICO MIDDLE TO UPPER LEVEL
TROUGH.

THE CARIBBEAN SEA...
ELONGATED UPPER LOW/TROUGH IS LOCATED OVER THE NW CARIBBEAN
EXTENDING FROM JUST N OF CUBA TO THE GULF OF HONDURAS. AN UPPER
LEVEL HIGH IS CENTERED NEAR NE NICARAGUA WITH A LARGE AREA OF
DIFFLUENCE ALOFT CENTERED IN THE SW CARIBBEAN WHERE THE FLOW
CHANGES BETWEEN THE HIGH AND LOW. SCATTERED TO NUMEROUS STRONG
THUNDERSTORMS ARE FOUND FROM 11N TO 13N BETWEEN 80W AND 85W
INCLUDING IN NICARAGUA. DRY AIR AND CLEAR CONDITIONS EXTEND
EAST OF 76W WITH ANOTHER UPPER HIGH CENTERED SOUTH OF HISPANIOLA
NEAR 16N70W. THE DRY AIR MASS WILL EXPAND SLOWLY OVER THE ENTIRE
CARIBBEAN THROUGHOUT 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
THUNDERSTORMS IN THE CENTRAL AND EASTERN CARIBBEAN.

THE WESTERN ATLANTIC OCEAN...
A STATIONARY FRONT PASSES THROUGH 32N65W TO A 1010 MB SURFACE
LOW PRESSURE CENTER NEAR 31N66W. THE STATIONARY FRONT CONTINUES
TO 29N73W AND 29N77W. A SURFACE TROUGH GOES FROM THIS SAME LOW
CENTER TO 27N70W AND 26N79W. NUMEROUS STRONG SHOWERS AND
THUNDERSTORMS ARE FOUND FROM 27N TO 28.5N BETWEEN 73W AND 76W.
THE CLOUDS ARE MORE SPREAD OUT AND SHOWERS/THUNDERSTORMS ARE
LESS CONCENTRATED AROUND THE SURFACE TROUGH. BROKEN TO OVERCAST
MULTILAYERED CLOUDS AND WIDELY SCATTERED TO SCATTERED MODERATE
SHOWERS/ISOLATED STRONG THUNDERSTORMS COVER THE ATLANTIC WATERS
FROM 20N TO 27N BETWEEN 64W AND 80W. OTHER ISOLATED MODERATE
SHOWERS ARE SEEN FROM 27N TO 32N BETWEEN 64W AND 68W.

THE EASTERN AND CENTRAL ATLANTIC OCEAN...
TROPICAL STORM MARIA IS MOVING NWWD OVER THE CENTRAL ATLC WATERS
UNDER THE SRN FLANK OF AN UPPER HIGH NEAR 28N52W.  IT SEEMS TO
HAVE LEFT THE INFLUENCE OF AN UPPER LOW NEAR 19N58W AND COULD
EVENTUALLY BECOME A HURRICANE AS IT ENTERS HIGHER LATITUDES.
ISOLATED TSTMS ARE FOUND FROM 16N TO 21N BETWEEN 55W AND 60W.
A RATHER DEEP UPPER TROUGH IS DIGGING INTO THE AREA FROM A LOW
NEAR 35N27W WITH A TROUGH SW TO 22N38W. AN EARLY-SEASON COLD
FRONT IS INTO THE AREA THROUGH 32N25W TO 28N30W TO 27N36W.
BROKEN TO OVERCAST MULTILAYERED CLOUDS ARE WITHIN 120 NM ON
EITHER SIDE OF 32N23W 27N30W 24N36W. POSSIBLE SHOWERS ARE IN
THIS CLOUDINESS. THIS FRONTAL POSITION IS MUCH FARTHER SOUTH
THAN AVERAGE FOR EARLY SEPTEMBER. THIS IS PROBABLY WHY ALL THE
TROPICAL 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 18N47W 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.

$$
MT

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