[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 212316
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT TUE JUN 21 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
2245 UTC.

...TROPICAL WAVES...

CENTRAL ATLC WAVE ALONG 44W S OF 12N MOVING W 10-15 KT. THE WAVE
IS LOW AMPLITUDE MOSTLY EMBEDDED IN A BAND OF ELY TRADES NEAR
THE ITCZ.  SCATTERED TSTMS ARE FROM 7N-10N BETWEEN 40W-45W.

E CARIBBEAN WAVE ALONG 64W S OF 19N MOVING W 20 KT.  THE WAVE
LOOKS BETTER-ORGANIZED THAN EARLIER TODAY WITH SOME EVIDENCE OF
BANDING AND TSTMS NEAR THE WAVE AXIS.  HOWEVER NO DEVELOPMENT OF
THE WAVE IS EXPECTED DUE TO INCREASING INTERACTION WITH AN UPPER
LOW TO THE WEST.  SCATTERED MODERATE CONVECTION IS FROM
13.5N-17N BETWEEN 64W-71W.  AN INCREASED CHANCE OF RAIN IS
LIKELY OVERNIGHT IN PUERTO RICO FROM THE WAVE WITH SHOWERS
OVERSPREADING HISPANIOLA TOMORROW THRU E CUBA AND JAMAICA THU.

CENTRAL CARIBBEAN TROPICAL WAVE ALONG 74W/75W S OF 19N MOVING W
20 KT. THE WAVE IS NEAR AN UPPER LOW... NOT GENERALLY A
FAVORABLE PLACE FOR CONVECTION... WITH ONLY A FEW TSTMS NEAR
15N75W AT THE NORTHERN END OF THE WAVE.  ANY CONVECTION
ASSOCIATED WITH THE WAVE SHOULD BE LIMITED TO THE SW CARIBBEAN
DURING THE NEXT FEW DAYS AS THE WAVE HEADS QUICKLY WWD.

TROPICAL WAVE CROSSING CENTRAL AMERICA ALONG 87W S OF 19N MOVING
W 15 KT. THE MOST PRONOUNCED CIRCULATION ASSOCIATED WITH THE
WAVE IS LOCATED OVER THE E PACIFIC SW OF COSTA RICA AND IT DOES
APPEAR THAT DIURNAL CONVECTION OVER CENTRAL AMERICA WAS ENHANCED
BY THE WAVE.  COMPUTER MODELS SUGGEST A LARGE AMOUNT OF TSTMS
OVER THE NW PART OF CENTRAL AMERICA TOMORROW INCLUDING SE
MEXICO.

...ITCZ...

ITCZ AXIS IS CENTERED ALONG 12N16W 8N30W 8N42W 7N47W 10N60W.
WIDELY SCATTERED MODERATE CONVECTION IS FROM 7N-10.5N BETWEEN
44W-57W.  ISOLATED TSTM CLUSTERS ARE WITHIN 120 NM OF THE ITCZ
E OF 35W.

...DISCUSSION...

GULF OF MEXICO...
PERSISTENT MID/UPPER LOW OVER THE SRN APPALACHIANS CONTINUES TO
KEEP THE GULF MOSTLY DRY SAVE FLORIDA WITH A TROUGH AXIS FROM
THE LOW FROM THE W FLORIDA PANHANDLE TO 24N90W IN THE CENTRAL
GULF.  ON THE E SIDE OF THE TROUGH...LARGE AMOUNTS OF TROPICAL
MOISTURE CONTINUE TO MOVE NORTHWARD AND FORM INTO SHOWERS/TSTMS
NEAR AND TO THE E OF A SURFACE TROUGH FROM CENTRAL FLORIDA TO
THE BAY OF CAMPECHE.  FLOODING... ESPECIALLY IN S FLORIDA
AREAS...WILL BE A CONCERN THROUGH THE REST OF TODAY AND TOMORROW
IF CONVECTION RE-DEVELOPS AS EXPECTED.  THE WET WEATHER PATTERN
SHOULD CONTINUE FOR THE NEXT COUPLE OF DAYS OVER FLORIDA WHILE
GENERALLY HOT DRY CONDITIONS DOMINATE THE REST OF THE GULF
COAST.  ELSEWHERE... WIDELY SCATTERED MODERATE CONVECTION IS
ALSO LOCATED AT THE TAIL END OF THE SFC TROF OVER THE BAY OF
CAMPECHE S OF 21N CONTINUING INLAND OVER YUCATAN.

CARIBBEAN...
MID/UPPER LEVEL LOW IS JUST S OF JAMAICA MOVING WNW NEAR 10 KT.
A BIT OF LIFT/DIVERGENCE OF THE E SIDE OF THE LOW IS CAUSING
TSTMS NEAR AN E CARIBBEAN WAVE.  ON THE W SIDE OF THE LOW...
CONVERGENCE ALOFT LIES OVER MOST OF THE W CARIBBEAN SAVE SOME
TSTMS OVER YUCATAN AND TYPICAL ITCZ TSTMS OVER THE FAR SW
CARIBBEAN.  TRADE-WIND SPEED CONVERGENCE AND SOME DIVERGENCE
ALOFT CONTINUES TO PRODUCE ISOLATED MODERATE CONVECTION S OF 13N
W OF S AMERICA.   A SURGE IN ELY TRADES SHOULD LEAD TO AN
ENHANCED SHOWER DAY IN THE WINDWARD ISLANDS TOMORROW WITH A
TROPICAL WAVE POSSIBLY LATE IN THE NEXT DAY CONTINUING THE
INCREASE RAIN CHANCES.  OTHERWISE THE BULK OF THE PRECIPITATION
SHOULD REMAIN NEAR THE TROPICAL WAVES AND OVER LAND DUE TO
DIURNAL CONVECTION.

ATLANTIC...
TROPICAL MOISTURE PLUME ORIGINATING OVER THE GULF OF MEXICO
COVERS MUCH OF THE FAR WRN ATLC...NW OF THE BAHAMAS. THE PLUME
IS MOSTLY ASSOCIATED WITH OVERCAST MID/UPPER LEVEL CLOUDINESS
BUT THERE ARE SOME EMBEDDED WIDELY SCATTERED SHOWERS W OF 75W.
STRONG UPPER LEVEL HIGH IS CENTERED ALONG 27N67W WITH RELATED
SURFACE 1022 MB HIGH LOCATED ABOUT 300 NM SSW OF BERMUDA.
FARTHER E...A PRE-FRONTAL TROF IS ALONG 32N40W 28N50W BRINGING
ISOLATED SHOWERS WITHIN 60 NM OF THE TROF.  FARTHER S... CENTRAL
ATLC MID/UPPER TROUGH IS LOCATED FROM 24N35W TO 15N46W WITH A
FEW HIGH CLOUDS FROM DISTANT TSTMS MOVING QUICKLY FROM SW TO NE
IN A WEAK SUBTROPICAL JET.  THIS FEATURE IS SUPPRESSING THE
TYPICAL AFRICAN UPPER HIGH WHICH AT THIS POINT IN THE YEAR
SHOULD BE EXTENDING FROM W AFRICA AROUND 14N-15N BUT IS FARTHER
S NEAR 10N-11N E OF 40W.  IN THE W TROPICAL ATLC... ELY
GENERALLY COVER THE NE S AMERICA AND THE SE CARIBBEAN FROM A
WEAK HIGH JUST W OF GUADELOUPE.... WITH DIVERGENCE FROM THE
CENTRAL ATLC TROUGH AND E CARIBBEAN HIGH PRODUCING A LARGE AREA
OF TSTMS WITHIN THE ITCZ.  LAST VISIBLE SATELLITE PICTURES
SUGGEST SOME AFRICAN DUST IS MOSTLY S OF 16N TO THE ITCZ E OF
50W BUT IS STILL UP AROUND 20N E OF 30W.  ALSO OF NOTE IS THE
VERY WEAK SUBTROPICAL RIDGE IN THE E ATLC... WITH MOST TRADES E
OF 40W AT 10 KT OR LESS.

$$
BLAKE

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