[Tropical] Tropical Weather Discussion

[Nashville EMWIN]

AXNT20 KNHC 170557
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 AM EDT TUE 17 AUG 2004

TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL
AMERICA...GULF OF MEXICO...CARIBBEAN SEA...NORTHERN 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
0415 UTC.

...SPECIAL FEATURES...

HURRICANE DANIELLE IS CENTERED NEAR 21.0N 39.2W AT 17/0300 UTC
MOVING NORTH NORTHWEST AT 15 KT.  MAXIMUM SUSTAINED WIND SPEED
IS 90 KT WITH GUSTS TO 110 KT AND THE ESTIMATED MINIMUM CENTRAL
PRESSURE IS 970 MB.  SEE LATEST NHC FORECAST/ADVISORY UNDER
AWIPS/WMO HEADERS MIATCMAT4/WTNT24 KNHC FOR MORE DETAILS.  EVEN
THOUGH AN INTERMITTENT RAGGED EYE REMAINS EVIDENT IN IR
SATELLITE IMAGERY...DANIELLE APPEARS TO BE EXPERIENCING SOME WLY
SHEAR AS EVIDENCED BY RESTRICTED UPPER LEVEL OUTFLOW OVER THE W
SEMICIRCLE. INCREASING SHEAR IS EXPECTED TO WEAKEN DANIELLE OVER
THE NEXT FEW DAYS. NUMEROUS STRONG CONVECTION IS WITHIN 75 NM OF
THE CENTER OVER THE SW SEMICIRCLE AND WITHIN 120 NM OVER THE NE
SEMICIRCLE.

...TROPICAL WAVES...

TROPICAL WAVE JUST W OF THE CAPE VERDE ISLANDS ALONG 26W S OF
16N MOVING W NEAR 20 KT. LATEST IR SATELLITE IMAGERY CONTINUES
TO SHOW A LOWER TO MID-LEVEL CIRCULATION NEAR 10N BUT CONVECTION
IS SPARSE.  ONLY A SMALL AREA OF ISOLATED MODERATE ACTIVITY IS
NOTED FROM 7N-11N BETWEEN 25W-30W.

TROPICAL WAVE APPROXIMATELY 800 NM E OF BARBADOS ALONG 45W S OF
15N MOVING W NEAR 20 KT. THE WAVE IS POORLY DEFINED IN SATELLITE
IMAGERY WITH ONLY ISOLATED ITCZ CONVECTION.

TROPICAL WAVE...REMNANTS OF T.S. EARL...IS OVER THE CENTRAL
CARIBBEAN ALONG 75W/76W S OF 18N MOVING W 25 KT.  EARLIER
QUIKSCAT DATA AND A NEARBY SHIP OBSERVATION AT 0000 UTC INDICATE
THAT THE WAVE CONTINUES TO PRODUCE GALE FORCE WINDS PRIMARILY E
OF THE AXIS FROM 14N-18N.  ASSOCIATED CONVECTION HAS WEAKENED
AND BECOME LESS ORGANIZED DURING THE LAST FEW HOURS WITH WIDELY
SCATTERED MODERATE ACTIVITY NOW EXTENDING FROM 14N-20N BETWEEN
70W-78W. THIS ACTIVITY IS CURRENTLY AFFECTING W PORTIONS OF
HISPANIOLA...E PORTIONS OF CUBA...AND JAMAICA.  GIVEN THE LACK
OF DEEP CONVECTION AND THE RATHER FAST MOTION OF THIS
WAVE...SIGNIFICANT RAINFALL AMOUNTS ARE LESS LIKELY.
HOWEVER...GUSTY WINDS IN PASSING SHOWERS/TSTMS WILL AFFECT
JAMAICA OVERNIGHT.

TROPICAL WAVE OVER THE W CARIBBEAN AND CENTRAL AMERICA ALONG 87W
S OF 17N MOVING W 20-25 KT.  THE SATELLITE SIGNATURE ASSOCIATED
WITH THIS WAVE IS CURRENTLY POOR AND THE POSITION IS BASED
PRIMARILY ON EXTRAPOLATION. UPPER AIR DATA FROM THE CAYMAN
ISLANDS INDICATES THE WAVE MIGHT BE A LITTLE FURTHER WEST BUT IT
IS INCONCLUSIVE.  WIDELY SCATTERED SHOWERS/TSTMS ARE OCCURRING
OVER NICARAGUA AND HONDURAS.

...ITCZ...
ITCZ AXIS IS ALONG 10N10W 8N20W 10N30W 12N35W 5N60W 8N75W.
SCATTERED MODERATE CONVECTION OVER PORTION OF VENEZUELA FROM
3N-8N BETWEEN 62W-70W.

...DISCUSSION...
GULF OF MEXICO...
MID/UPPER LEVEL RIDGE PREVAILS OVER MOST OF THE GLFMEX EXTENDING
FROM S FLORIDA WESTWARD TO 22N95W WHILE A SERIES OF SHORTWAVE
TROUGHS BYPASS THE AREA TO THE N OVER THE CENTRAL AND E UNITED
STATES.  A WEAK MID-UPPER LEVEL TROUGH LIES ALONG THE COAST OF
MEXICO FROM VERACRUZ NWD TO S TEXAS BUT THIS FEATURE IS UNABLE
TO PRODUCE ANY SIGNIFICANT WEATHER. THE ONLY CONVECTION OF NOTE
LIES OVER THE BAY OF CAMPECHE WITH A SMALL AREA OF SCATTERED
MODERATE ACTIVITY RESIDES S OF 20N. AT THE SURFACE...REMNANT
FRONTAL TROUGH EXTENDS FROM THE FLORIDA PANHANDLE SW TO JUST E
OF BROWNSVILLE TEXAS NEAR 25N96W. THE AIRMASS N OF THE BOUNDARY
IS STILL FAIRLY DRY SUPPRESSING CONVECTION ALONG THE N GULF
COAST. ELSEWHERE...A SECOND TROUGH OVER THE W ATLC HAS MOVED
WESTWARD OVER S FLORIDA AND THE SE GLFMEX PRODUCING ISOLATED
SHOWERS/THUNDERSTORMS S OF 26N E OF 87W.

CARIBBEAN SEA...
THE PRIMARY WEATHER MAKER OVER THE CARIBBEAN IS THE REMNANTS OF
T.S. EARL WHICH DEGENERATED INTO A TROPICAL WAVE ON MONDAY.
HOWEVER...THE WAVE CONTINUES TO PRODUCE STRONG GUSTY WINDS AND
WIDELY SCATTERED SHOWERS/THUNDERSTORMS AS IT MARCHES RAPIDLY
WESTWARD AT 25 KT. A SECOND TROPICAL WAVE OVER HONDURAS IS
ENHANCING TYPICAL CONVECTION OVER CENTRAL AMERICA. OVER THE E
CARIBBEAN...VERY DRY MIDDLE TO UPPER LEVEL AIR HAS MOVED IN FROM
THE ATLC AND IS SUPPRESSING CONVECTIVE ACTIVITY.

SUBTROPICAL ATLANTIC...
A SHORTWAVE RIDGE-TROUGH PATTERN PREVAILS OVER THE W ATLC WITH A
MID-UPPER LEVEL RIDGE EXTENDING FROM THE N BAHAMAS NEWD TO
BEYOND 33N73W AND A MID-UPPER LEVEL TROUGH EXTENDING FROM JUST
SW OF BERMUDA NEAR 32N67W SWD OVER THE S BAHAMAS.  THERE IS JUST
ENOUGH INSTABILITY ASSOCIATED WITH THE UPPER TROUGH TO SPARK
WIDELY SCATTERED SHOWERS ALONG A LINE EXTENDING FROM THE CENTRAL
BAHAMAS EWD ALONG 25N70W TO BERMUDA.  A LARGE MID-UPPER LEVEL
LOW IS LOCATED OVER THE CENTRAL ATLC NEAR 29N45W MOVING WNW 15
KT. SUBSIDENCE ASSOCIATED WITH THE LARGE UPPER LOW COVERS THE
AREA S OF 25N BETWEEN 40-70W. OVER THE E ATLC...HURRICANE
DANIELLE IS NOW MOVING NWD AROUND THE W PERIPHERY OF A MID-UPPER
LEVEL RIDGE ALONG 20N E OF 40W.  AT THE SURFACE...SUBTROPICAL
RIDGE EXTENDS FROM A 1027 MB HIGH OVER THE CENTRAL ATLC NEAR
35N55W SW THROUGH 31N60W TO 29N75W. THE RIDGE BECOMES DISRUPTED
OVER BERMUDA AND FLORIDA BY A WEAK LOW LEVEL TROUGH EXTENDING
FROM 31N73W TO S FLORIDA.

TROPICAL ATLANTIC...
STRONG SUBSIDENCE OVER THE CENTRAL ATLC W OF DANIELLE EXTENDS
WELL INTO THE TROPICAL ATLC PRODUCING VERY DRY AIR AND GENERALLY
TRANQUIL WEATHER.  FURTHER E...E/W ORIENTED MID-UPPER LEVEL
RIDGE POSITIONED JUST N OF THE CAPE VERDE ISLANDS IS PRODUCING
DEEP ELY FLOW E OF HURRICANE DANIELLE.  THIS REGIME IS GENERALLY
MORE FAVORABLE FOR ITCZ/WAVE RELATED CONVECTION BUT NEITHER ARE
CURRENTLY PRODUCING SIGNIFICANT ACTIVITY.

$$
RHOME





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