[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 292353
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT SUN MAY 29 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
2315 UTC.

...TROPICAL WAVES...

EAST ATLANTIC TROPICAL WAVE ALONG 37W S OF 14N MOVING W AT AN
ESTIMATED SPEED OF 15 KT OR ABOUT 6 DEG/DAY. THE WAVE IS LOCATED
BENEATH A SHARP MID/UPPER LEVEL TROF WITH ASSOCIATED SUBSIDENCE
SUPPRESSING CONVECTION AND THUS MASKING ANY SATELLITE SIGNATURE.
CURRENT POSITION IS BASED MAINLY ON EXTRAPOLATION.

TROPICAL WAVE OVER THE E CARIBBEAN ALONG 64W S OF 20N MOVING W
AT AN ESTIMATED SPEED OF 20 OR ABOUT 8 DEG/DAY. THE CIRCULATION
ASSOCIATED WITH THE WAVE HAS BECOME A LITTLE LESS DISTINCT IN
SATELLITE IMAGERY AND ASSOCIATED CONVECTION SHOWS LITTLE
ORGANIZATION.  MOST OF THE ENERGY ASSOCIATED WITH THIS WAVE IS
CONFINED OVER S AMERICA WITH ONLY ISOLATED SHOWERS/TSTMS OVER
THE E CARIBBEAN WATERS E OF 70W.

W CARIBBEAN TROPICAL WAVE ALONG 79W/80W S OF 18N MOVING W 10-15
KT OR ABOUT 5-6 DEG/DAY. A 5-DAY LOOP OF SATELLITE IMAGERY SHOWS
THE WAVE LOST MOST OF ITS ENERGY AS IT CROSSED THE CARIBBEAN
BASIN AND THERE IS CURRENTLY NO SIGNIFICANT CONVECTION.

TROPICAL WAVE OVER CENTRAL AMERICA ALONG 90W S OF 16N MOVING W
10 KT. MOISTURE ASSOCIATED WITH THE WAVE IS MOVING ACROSS
CENTRAL AMERICA AND THE YUCATAN PENINSULA PRODUCING ENHANCED
DIURNAL CONVECTION.

...ITCZ...

ITCZ AXIS IS CENTERED ALONG 12N10W 7N35W 9N60W. WIDELY SCATTERED
MODERATE CONVECTION WITHIN 300 NM EITHER SIDE OF ITCZ E OF 20W.

...DISCUSSION...

GULF OF MEXICO...
ANOTHER QUIET DAY CONVECTION WISE AS A DRY/CAPPING AIRMASS
REMAINS ENTRENCHED. AS SUCH...MUCH OF THE AREA REMAINED FREE OF
AFTERNOON SHOWERS/TSTMS WITH THE ONLY ACTIVITY OF NOTE BEING A
FEW ISOLATED SHOWERS/TSTMS ALONG THE N GULF COAST FROM LOUISIANA
EWD THROUGH THE FLORIDA PANHANDLE. THIS ACTIVITY IS ASSOCIATED
WITH A MIDDLE TO UPPER LEVEL SHORTWAVE WHICH IS FORECAST TO
STRADDLE THE AREA THROUGH THE NEXT 24-48 HOURS. WHILE THE BEST
LIFT/DYNAMICS WILL BE JUST N OF THE AREA...ASSOCIATED
SHOWERS/TSTMS WILL BE CLOSE ENOUGH THAT OUTFLOW BOUNDARIES MAY
ENHANCE AFTERNOON SHOWERS/TSTMS OVER N FLORIDA. INSPECTION OF
AREA SOUNDINGS SHOWS THAT DEEP-LAYERED MOISTURE IS SLOWLY
INCHING UPWARD COURTESY OF AN AMPLIFYING TROUGH OVER MEXICO.
THIS TROUGH IS FORECAST TO BECOME ESTABLISHED OVER THE W GLFMEX
MON AND TUE THEN SLIDE TO THE CENTRAL GLFMEX ON WED.  THIS
PATTERN WILL PRODUCE A MUCH MORE UNSTABLE ENVIRONMENT AS
DEEP-LAYERED MOISTURE SURGES NWD OVER THE E HALF OF THE AREA.
TONIGHT AND MONDAY LOOK TO BE THE TRANSITION PERIOD WITH
PRECIPITABLE WATER VALUES MOVING CLOSER TO TYPICAL SUMMERTIME
VALUES.  AS SUCH...EXPECT INCREASING COVERAGE OF AFTERNOON
SHOWERS/TSTMS OVER FLORIDA THIS WEEK WITH TUE AND WED LOOKING
RATHER ACTIVE.

CARIBBEAN...
A WELL DEFINED MIDDLE TO UPPER LEVEL ANTICYCLONE IS LOCATED OVER
CENTRAL AMERICA NEAR HONDURAS WITH THE S EXTENT OF A AN W ATLC
SHORTWAVE TROUGH CLIPPING HISPANIOLA.  AT THE SURFACE...AFRICAN
DUST CONTINUES TO SPREAD WESTWARD ACROSS THE AREA ON THE HEELS
OF A TROPICAL WAVE NEAR 80W. ASSOCIATED AIRMASS IS SLIGHTLY
DRIER WITH PRECIPITABLE WATER VALUES FROM SOUNDINGS OVER THE E
CARIBBEAN DIPPING BELOW 2 INCHES. THE EXTREME W PORTION OF THE
CARIBBEAN AND CENTRAL AMERICA REMAINING QUITE MOIST WITH PWAT
VALUES ABOVE 2 INCHES.  ACCORDINGLY...AFTERNOON SHOWERS/TSTMS
WERE MOST NUMEROUS OVER THE YUCATAN PENINSULA AND CENTRAL
AMERICA TODAY.  THE AFRICAN DUST AND RELATIVELY DRIER AIRMASS
SHOULD CONTINUE SPREADING WESTWARD OVER THE W CARIBBEAN TONIGHT
AND MONDAY WITH DEEP-LAYERED MOISTURE REMAINING HIGHEST OVER
CENTRAL AMERICA AND N PORTIONS OF S AMERICA.

ATLANTIC...
WELL-DEFINED MIDDLE TO UPPER LEVEL RIDGE EXTENDS FROM THE
CARIBBEAN EWD TO ROUGHLY 20N45W WITH FLAT/ZONAL FLOW PREVAILING
TO THE N OVER THE W HALF OF THE DISCUSSION AREA.  TWO SHORTWAVE
TROUGHS EMBEDDED WITHIN THE WLY FLOW ARE THE PRIMARY WEATHER
FEATURES.  THE EASTERNMOST TROUGH EXTENDS FROM 32N40W TO 18N50W
AND IS PRODUCING AN AREA OF CLOUDINESS AND WIDELY SCATTERED
SHOWERS/TSTMS FROM 25N-32N BETWEEN 35W-45W. THE WESTERNMOST
TROUGH CURRENTLY EXTENDS FROM 30N65W TO HISPANIOLA AND IS
GENERATING A SMALL AREA OF SCATTERED SHOWERS/TSTMS FROM 24N-26N
BETWEEN 61W-67W.  AT THE SURFACE...A WEAK STATIONARY FRONT LIES
JUST N OF THE AREA FROM BERMUDA TO THE SE UNITED STATES NEAR
GEORGIA. THIS BOUNDARY IS EXPECTED TO REMAIN N OF 30N WITH
LIMITED IMPACT ON THE DISCUSSION AREA.  SHIFTING EWD...A
STATIONARY CUT-OFF UPPER LOW IS CENTERED OVER THE TROPICAL E
ATLC NEAR 16N35W WITH A BUILDING RIDGE TO THE EAST OVER W AFRICA
AND THE CAPE VERDE ISLANDS.  CONFLUENCE AND SUBSIDENCE TO THE
WEST OF THE UPPER LOW SHOULD CONTINUE TO SUPPRESS ITCZ ACTIVITY
BETWEEN 35-55W WHILE DIFFLUENCE TO THE EAST WILL FAVOR ITCZ E OF
35W.  IN THE LOWER LEVELS...SUBTROPICAL RIDGE REMAINS
WELL-DEFINED OVER THE E AND W ATLC BUT HAS BECOME PARTIALLY
DISRUPTED OVER THE CENTRAL ATLC BY A BROAD AREA OF LOW PRESSURE
BETWEEN 40W-50W.  THE EXPANSIVE PLUME OF AFRICAN DUST REMAINS
EVIDENT IN EARLIER VISIBLE SATELLITE IMAGERY EXTENDING ACROSS
THE ENTIRE ATLC GENERALLY S OF 22N TO THE ITCZ.

$$
RHOME



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