[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 290606
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 AM EDT TUE AUG 29 2006

TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL
AMERICA...THE GULF OF MEXICO...THE CARIBBEAN SEA...NORTHEASTERN
SECTIONS OF SOUTH AMERICA...AND THE 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.

...SPECIAL FEATURE...
THE CENTER OF TROPICAL STORM ERNESTO IS NEAR 22.2N 78.3W AT
29/0600 UTC. THIS POSITION IS NEAR THE NORTHERN COAST OF CUBA
ABOUT 20 MILES...30 KM...SOUTH-SOUTHEAST OF CANAGUA. THIS
POSITION IS ALSO ABOUT 275 MILES...445 KM...SOUTHEAST OF KEY
WEST FLORIDA AND ABOUT 265 MILES ...425 KM...SOUTH-SOUTHEAST
OF MIAMI FLORIDA.  THE ESTIMATED MINIMUM CENTRAL PRESSURE IS
1007 MB. THE MAXIMUM SUSTAINED WIND SPEEDS ARE 35 KT WITH GUSTS
TO 45 KT. SOME GRADUAL STRENGTHENING IS EXPECTED AFTER ERNESTO
EMERGES OVER THE WARM WATERS OF THE FLORIDA STRAITS AND UPPER
LEVEL WINDS BECOME MORE FAVORABLE.  ERNESTO IS MOVING TOWARD THE
WEST-NORTHWEST NEAR 10 KT. A TURN TO THE NORTHWEST IS EXPECTED
OVER THE NEXT 12 TO 24 HOURS.  ON THE FORECAST TRACK...ERNESTO
WILL BE MOVING OVER WATER EARLY TUESDAY MORNING...AND BE NEAR
THE FLORIDA KEYS BY TUESDAY EVENING. PLEASE REFER TO THE LATEST
NHC FORECAST ADVISORY UNDER HEADERS MIATCMAT5/WTNT25 KNHC AND
THE PUBLIC ADVISORY MIATCPAT5/WTNT35 KNHC FOR MORE DETAILS. DEEP
CONVECTION ASSOCIATED WITH ERNESTO REMAINS LIMITED. HEAVY
SHOWERS AND THUNDERSTORMS ARE STILL SEEN OVER EASTERN
CUBA...LIKELY AIDED BY UPSLOPE FLOW ON THE SE QUADRANT OF
ERNESTO. OTHER CLUSTERS OF MODERATE CONVECTION ARE SEEN IN THE
WATERS BETWEEN ANDROS ISLAND AND CENTRAL CUBA...ALONG WITH OVER
THE SE BAHAMAS AND ADJACENT WATERS.

...TROPICAL WAVES...
A LOW AMPLITUDE TROPICAL WAVE HAS BEEN ADDED ALONG 23W/24W S OF
23N...MOVING W NEAR 15 KT. THIS WAVE IS DIFFICULT TO LOCATE AS
IT IS SUPERIMPOSED ON THE MONSOON TROUGH. HOWEVER...HOVMOLLER
DIAGRAMS SUGGEST THE WAVE IS THERE AND CURRENT SATELLITE IMAGERY
STILL SHOWS A REGION OF LOW-MID LEVEL CYCLONIC TURNING BETWEEN
22W-28W. ISOLATED SHOWER AND TSTMS ARE NOTED WITHIN 200NM OF
EITHER SIDE OF THE AXIS.

A HIGH AMPLITUDE TROPICAL WAVE IS ALONG 40W S OF 24N MOVING W
NEAR 15 KT. A 1011 MB LOW IS ALONG THE WAVE NEAR 17N. BROAD
CYCLONIC TURNING REMAINS VERY EVIDENT IN THE LOW TO MID CLOUD
FIELD AROUND THE WAVE AXIS AND SURFACE LOW...THOUGH DEEP
CONVECTION REMAINS MINIMAL. A COUPLE SMALL CELLS OF MODERATE
CONVECTION COVER THE AREA WITHIN 20NM OF 15N44W AND 17N39W.

...THE ITCZ...
ITCZ AXIS IS CENTERED ALONG 13N12W 11N22W 11N25W 12N38W 10N42W
TO THE COAST OF SOUTH AMERICA NEAR 9N60W. SCATTERED
MODERATE/ISOLATED STRONG CONVECTION IS MOSTLY INLAND OVER AFRICA
E OF 18W FROM 9N-17N LIKELY ASSOCIATED WITH THE NEXT TROPICAL
WAVE. A NEW CLUSTER OF SCATTERED MODERATE/ISOLATED STRONG
CONVECTION HAS DEVELOPED OVER THE LAST FEW HOURS BETWEEN THE SRN
CAPE VERDE ISLANDS AND AFRICA...FROM 12N-14N BETWEEN 18W-21W.
SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS FROM 8N-13N
BETWEEN 29W-37W. THE WRN HALF OF THE AXIS IS FAIRLY QUIET BUT
NUMEROUS SHOWERS AND TSTMS ARE OVER THE NRN PORTION OF S AMERICA
LIKELY ENHANCED BY THE ITCZ.

...DISCUSSION...

THE GULF OF MEXICO...
ALL EYES REMAIN ON TROPICAL STORM ERNESTO AS THIS SYSTEM WILL
HAVE AN IMPACT ON THE WEATHER IN FLORIDA AND THE ERN GULF OVER
THE NEXT COUPLE OF DAYS. FOR MORE INFORMATION REFER TO THE
SPECIAL FEATURE SECTION ABOVE. CURRENTLY IN THE GULF SCATTERED
MODERATE CONVECTION IS SEEN PUSHING W OF THE W COAST OF
FLORIDA...IN THE ERN GULF WATERS FROM 24N-28N BETWEEN 82W-84W.
THIS SEEMS MOST ASSOCIATED WITH UPPER DIFFLUENT AIR BETWEEN THE
UPPER HIGH SEEN SPINNING OVER THE SE US AND THE UPPER LOW MOVING
W THROUGH THE FLORIDA STRAITS. MID TO UPPER LEVEL CYCLONIC FLOW
IS DOMINATING THE WRN HALF OF THE GULF THIS EVENING...AROUND A
WELL DEFINED UPPER LOW CENTERED NEAR 23N94W. A FAIRLY WEAK
SURFACE GRADIENT IS OVER THE GULF...WITH ASSOCIATED LIGHT WINDS
AND LOW SEAS BEING OBSERVED. THE ONLY WINDS OVER 10 KT SEEN ARE
JUST OFF THE COAST OF TEXAS WHERE THE WEAK WRN EXTENSION OF THE
ATLC HIGH IS INTERACTING WITH A 1006MB SURFACE LOW OVER MEXICO
NEAR 26N101W.

THE CARIBBEAN SEA...
THE CENTER OF TROPICAL STORM ERNESTO IS OVER CENTRAL CUBA
PRODUCING HEAVY RAINFALL OVER PORTIONS OF NRN HAITI...ERN AND
CENTRAL CUBA AND THE CNTRL AND SE BAHAMAS. THE REMAINDER OF THE
CARIBBEAN OUTSIDE OF THE VICINITY OF ERNESTO IS FAIRLY QUIET
WITH MINIMAL SHOWER/TSTM ACTIVITY NOTED. DRY/STABLE AIR IS OVER
THE FAR NW CARIBBEAN IN ASSOCIATION WITH A WEAK UPPER HIGH IN
THE AREA. DRY/STABLE AIR CONTINUES TO BE ADVECTED W INTO THE ERN
AND CNTRL CARIBBEAN AROUND THE SRN PERIPHERY OF AN UPPER HIGH.
TRADE WINDS ARE A FAIRLY LIGHT 5-15KT ACROSS MUCH OF THE AREA
DUE TO A WEAKENING OF THE GRADIENT S OF ERNESTO. CONSIDERABLY
STRONGER WINDS SHOULD BE EXPECTED NEAR ERNESTO.

THE ATLANTIC OCEAN...
A MID-UPPER LEVEL RIDGE CENTERED OVER THE SE US HAS RIDGING THAT
STRETCHES E TO 65W ALONG 31N/32N. AN UPPER TROUGH LIES TO THE E
OF THE RIDGE BETWEEN 45W-65W MAINLY N OF 20N. AN ASSOCIATED WEAK
SURFACE TROUGH/OLD FRONTAL BOUNDARY IS UNDER THIS VICINITY ALONG
26N61W 32N53....ALONG WITH A PAIR OF WEAK 1013MB SURFACE LOWS
NEAR 30N56W AND 32N53W. CLUSTERS OF MODERATE CONVECTION HAVE
DEVELOPED IN THE ASSOCIATED LOW LEVEL CONFLUENT ZONE FROM
29N-35W BETWEEN 49W-57W. THE REMAINDER OF THE ATLC IS DOMINATED
BY A BROAD UPPER RIDGE EXTENDING FROM AFRICA TO NEAR 50W WITH
MULTIPLE HIGH CENTERS.  A COUPLE OF WEAK BENIGN UPPER LOWS ARE
ON THE W PERIPHERY OF THE RIDGE PRODUCING LITTLE...IF
ANY...WEATHER. ANOTHER UPPER LOW CLIPS THE AREA CENTERED JUST
OFF THE COAST OF MOROCCO NEAR 31N14W. AT THE SURFACE...A WEAK
PRES GRAD EXISTS W OF 50W DUE TO THE WEAK FRONT DRAPED ACROSS
THE NRN PORTION OF THE AREA. STRONGER GRAD IN THE E ATLC AS A
1027 MB HIGH IS CENTERED N OF THE AZORES AND A 1011 MB LOW ALONG
A TROPICAL WAVE NEAR 17N40W.

$$
WILLIS


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