[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 290004
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT MON AUG 28 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
2315 UTC.

...SPECIAL FEATURE...
THE CENTER OF TROPICAL STORM ERNESTO IS NEAR 21.4N 77.4W AT
29/0000 UTC. THIS POSITION IS JUST INLAND OVER EASTERN
CUBA...ABOUT 30 MILES...45 KM...EAST OF CAMAGUEY. OVER THE PAST
SEVERAL HOURS ERNESTO HAS BEEN MOVING TOWARD THE WEST-NORTHWEST
NEAR 10 KT.  HOWEVER...A NORTHWESTWARD MOTION IS EXPECTED TO
RESUME LATER TONIGHT...WHICH WOULD TAKE THE CENTER OF
CIRCULATION OFF THE NORTH COAST OF CUBA INTO THE ATLANTIC DURING
THE NEXT 6 TO 12 HOURS. THE ESTIMATED MINIMUM CENTRAL PRESSURE
IS 1007 MB. THE MAXIMUM SUSTAINED WIND SPEEDS ARE 35 KT WITH
GUSTS TO 45 KT. PLEASE REFER TO THE LATEST NHC FORECAST ADVISORY
UNDER HEADERS MIATCMAT5/WTNT25 KNHC AND THE PUBLIC ADVISORY
MIATCPAT5/WTNT35 KNHC FOR MORE DETAILS. ERNESTO BECAME QUITE
DISORGANIZED TODAY AS IT INTERACTED WITH THE MOUNTAINOUS TERRAIN
OF CUBA WITH MUCH OF THE CONVECTION REMAINING TO THE E OF THE
CENTER OVER ERN CUBA...THE WINDWARD PASSAGE AND WRN HAITI. A
SMALL UPPER LOW TO THE N-NW OF ERNESTO MAY HAVE ALSO PROVIDED
SOME SHEAR AIDING IN THE DISORGANIZATION. HOWEVER OVER THE PAST
SEVERAL HOURS NEW BURSTS OF CONVECTION HAVE FORMED TO THE N AND
W OF THE CENTER. RADAR IMAGERY FROM CUBA SHOWS SOME OF THESE
SPIRAL BANDS AND CELLS BECOMING BETTER DEFINED. THIS MAY BE AN
INDICATION OF THE START OF AN ORGANIZING/STRENGTHENING TREND.
STRENGTHENING TO A STRONG TROPICAL STORM IS FORECAST AS ERNESTO
MOVES BACK OVER WATER TOWARDS S FLORIDA.

...TROPICAL WAVES...
A HIGH AMPLITUDE TROPICAL WAVE IS ALONG 39W S OF 24N MOVING W 15
KT. A 1010 MB LOW IS ALONG THE WAVE NEAR 17.5N. THE SFC LOW IS
RATHER LARGE AND WELL-DEFINED ON SATELLITE IMAGERY BUT IS DEVOID
OF CONVECTION AS IT IS EMBEDDED IN A DRY STABLE ENVIRONMENT.

A TROPICAL WAVE WILL LIKELY BE ADDED TO THE 00 UTC SURFACE
ANALYSIS ALONG 23W/24W. THIS WAVE IS NOT VERY HIGH AMPLITUDE AND
IS DIFFICULT TO LOCATE AS A MONSOON TROF COVERS MUCH OF THE E
TROPICAL ATLC. HOWEVER BASED UPON HOVMOLLER DIAGRAMS AND CURRENT
SATELLITE IMAGERY LOW-MID LEVEL CYCLONIC TURNING IS NOTED
BETWEEN 21W-25W. IN ADDITION THE GFS MODEL DOES SHOW A WAVE LIKE
FEATURE IN A SIMILAR LOCATION.

...THE ITCZ...
ITCZ AXIS IS CENTERED ALONG 12N15W 11N23W 14N37W 9N41W 8N63W.
NUMEROUS MODERATE CONVECTION IS MOSTLY INLAND OVER AFRICA E OF
16W FROM 10N-16N LIKELY AHEAD OF A TROPICAL WAVE. SCATTERED
MODERATE CONVECTION IS FROM 8N-13N BETWEEN 25W-35W. 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 ARE 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...THE WEATHER IS QUIET ACROSS A
GOOD PORTION OF THE GULF WITH A MID-UPPER LEVEL HIGH CENTERED
OVER GEORGIA PRODUCING MODERATE SUBSIDENCE ABOVE MOST OF THE
REGION E OF 88W. AN UPPER TROUGH IS DIGGING IN THE SOUTH CENTRAL
U.S. BUT CURRENTLY REMAINS N OF THE AREA. THESE FEATURES WILL
PROVIDE THE STEERING FOR ERNESTO. A WEAK SFC TROF HAS DEVELOPED
IN THE NE GULF FROM THE BIG BEND AREA OF FLORIDA TO 28N87W.
ISOLATED SHOWERS HAVE FLARED UP WITHIN 60 NM OF THE BOUNDARY. AN
UPPER LEVEL LOW IS IN THE BAY OF CAMPECHE NEAR 22N92W MOVING
QUICKLY W. ISOLATED TO SCATTERED SHOWERS ARE WITHIN 300 NM OF
THE LOW CENTER. SFC WINDS ARE LIGHT AND VARIABLE ACROSS MOST OF
THE AREA.

THE CARIBBEAN SEA...
THE CENTER OF TROPICAL STORM ERNESTO IS OVER ERN CUBA PRODUCING
HEAVY RAINFALL OVER PORTIONS OF WRN HAITI...ERN AND CNTRL CUBA
AND THE CNTRL BAHAMAS. ADDITIONAL RAINFALL AMOUNTS OF 2 TO 5
INCHES ARE POSSIBLE OVER WRN HAITI AND 3 TO 6 INCHES OVER E CUBA
WITH ISOLATED AMOUNTS UP TO 10 INCHES. DEBRIS MOISTURE HAS
SPREAD WELL E OF THE STORM TO ABOUT 66W MOSTLY N OF 16N. FOR
MORE DETAILS REFER TO THE SPECIAL FEATURE SECTION ABOVE. THE
REMAINDER OF THE CARIBBEAN HAS BROKEN CLOUDINESS AND ISOLATED
SHOWERS. VERY DRY STABLE UPPER LEVEL AIR FROM THE TROPICAL ATLC
IS BEGINNING TO SPREAD W INTO THE ERN CARIBBEAN ON THE W
PERIPHERY OF AN UPPER RIDGE. TRADE WINDS ARE A FAIRLY LIGHT
10-15 KT ACROSS MUCH OF THE AREA...EXCEPT FOR CONSIDERABLY
STRONGER WINDS NEAR ERNESTO.

THE ATLANTIC OCEAN...
A MID-UPPER LEVEL RIDGE CENTERED OVER GEORGIA HAS RIDGING THAT
STRETCHES E TO 65W ALONG 32N. AN UPPER TROUGH LIES TO THE E OF
THE RIDGE WITH THE UPPER AXIS ALONG 32N51W 27N55W 21N61W. AN
ASSOCIATED VERY WEAK FRONTAL BOUNDARY ENTERS THE AREA ALONG
32N51W TO A 1013 MB LOW NEAR 30N57W THEN AS A DISSIPATING FRONT
ALONG 26N64W 32N72W. SCATTERED SHOWERS EXIST FROM 27N-32N
BETWEEN 54W-58W.  CONSIDERABLE CLOUDINESS AND ISOLATED SHOWERS
ARE N OF 21N BETWEEN 46W-63W. 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. A MORE NOTICEABLE UPPER LOW IS NEAR 17N40W. UPPER
DIFFLUENCE ON THE SW SIDE OF THE CIRCULATION IS LIKELY ENHANCING
CONVECTION IN THE ITCZ BETWEEN 25W-35W. ANOTHER UPPER LOW CLIPS
THE AREA CENTERED JUST OFF THE COAST OF MOROCCO NEAR 31N13W. 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 1028 MB HIGH IS CENTERED N OF THE AZORES AND
A 1010 MB LOW ALONG A TROPICAL WAVE NEAR 17N39W.

$$
CANGIALOSI


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