TROPICAL DISCUSSION - INTERNATIONAL DESKS
NWS HYDROMETEOROLOGICAL PREDICTION CENTER CAMP SPRINGS MD
226 PM EDT MON AUG 24 2009
 
DISCUSSION FROM AUG 24/0000 UTC. THE PATTERN ACROSS THE DOMAIN
EVOLVED AS THE GLOBAL MODELS PREVIOUSLY SUGGESTED...WITH THE
SUBTROPICAL RIDGE PATTERN BECOMING ILL ORGANIZED AS TUTT(S) AND
TUTT LOWS POPULATE THE DOMAIN.

OVER THE WESTERN PORTIONS OF THE DOMAIN...MEANWHILE...A 250 HPA
RIDGE EXTENDS TO THE NORTH-NORTHEAST ACROSS NORTHWEST MEXICO TO
THE SOUTHWEST/CENTRAL USA. THIS SUSTAINS THE SOUTHWARD
AMPLIFICATION OF A TROUGH ACROSS THE EASTERN USA TO THE GULF OF
MEXICO...WHERE IT IS INTERACTING WITH A TUTT OVER SOUTHERN MEXICO.
THE TUTT WILL DRIFT WEST ALONG 100W/102W BY 24 HRS...AND BY 48/72
HRS IT WILL STALL OVER COLIMA/JALISCO-NAYARIT. AS THE TUTT MOVES
WEST...IT WILL ENHANCE UPPER CONVERGENCE ACROSS WESTERN STATES OF
MEXICO AND LEAD TO DECREASE IN CONVECTION ALONG THE SIERRA MADRE
OCCIDENTAL BETWEEN SONORA/CHIHUAHUA-DURANGO/SINALOA. ONLY AREA
WHERE THE MODELS CONSISTENTLY FORECAST MORE ACTIVITY IS OVER
CENTRAL MEXICO...TO CONCENTRATE ON THE SIERRA MADRE DEL SUR IN THE
STATES OF MICHOACAN-GUANAJUATO AND MEXICO/MEXICO DF. ON DAY 01 WE
EXPECT ACCUMULATION OF 10-15MM/DAY AND MAXIMA OF 15-35MM...WHILE
ON DAYS 02-03 EXPECT ACCUMULATION OF 10-15MM/DAY AND MAXIMA OF
20-45MM. 

AN UPPER LEVEL RIDGE WILL EXTEND ACROSS THE CENTRAL/WESTERN
CARIBBEAN-CENTRAL AMERICA...ACROSS CUBA/THE BAHAMAS. A
RETROGRESSING TUTT WILL FORCE THIS RIDGE TO ERODE/COLLAPSE OVER
THE CENTRAL CARIBBEAN BY 48-54 HRS...WHILE IT IS TO PERSIST ACROSS
CENTRAL AMERICA/WESTERN CARIBBEAN-CUBA. THIS IS TO PROVIDE
VENTILATION ALOFT TO DIURNAL CONVECTION FROM SOUTHERN MEXICO TO
PANAMA/COSTA RICA. OVER SOUTHERN MEXICO-GUATEMALA/THE YUCATAN AND
BELIZE WE EXPECT RAINFALL ACCUMULATION OF 10-15MM/DAY AND MAXIMA
OF 20-35MM/DAY. OVER EL SALVADOR-HONDURAS AND NICARAGUA EXPECT
ACCUMULATION OF 05-10MM/DAY AND MAXIMA OF 15-30MM/DAY. OVER
PANAMA-COSTA RICA EXPECT ACCUMULATION OF 10-15MM/DAY AND MAXIMA OF
20-35MM/DAY. OVER CUBA...SEA BREEZE RELATED CONVERGENCE WILL
RESULT IN RAINFALL AMOUNTS OF 05-10MM/DAY AND MAXIMA OF 15MM/DAY.

A TUTT LOW NORTH OF PUERTO RICO/VIRGIN ISLANDS ANCHORS A BROAD
TROUGH THAT EXTENDS BETWEEN 70W-54W AND TO THE NORTH OF 14N. A
RIDGE IS TO GRADUALLY BUILD TO THE EAST OF THIS TROUGH OVER THE
TROPICAL ATLANTIC...DISPLACING THE TUTT FARTHER WEST INTO THE
CARIBBEAN. BY 24 HRS THE TUTT LOW WILL MOVE TO THE MONA
PASSAGE...MEANDERING EAST OVER HAITI BY 60-72 HRS. AT MID LEVELS
IT REFLECTS AS AN INVERTED TROUGH WITH AXIS NORTH FROM CARACAS
VENEZUELA-PUERTO RICO TO THE ATLANTIC. THROUGH 48-60 HRS IT WILL
DRIFT TO LA GUAJIRA PENINSULA/NORTHWEST VENEZUELA-HISPANIOLA-TURKS
AND CAICOS...WHERE IT WILL REMAIN THROUGH 72-78 HRS. THIS FEATURE
IS ENHANCING CONVECTION ACROSS THE FRENCH AND LEEWARD/VIRGIN
ISLANDS...WHERE WE EXPECT SCATTERED CONVECTION WITH ACCUMULATION
OF 05-10MM/DAY AND MAXIMA OF 15-20MM/DAY. OVER PUERTO RICO IT IS
TO ALSO ENHANCE CONVECTION DURING THE NEXT COUPLE OF DAYS...TO
FAVOR RAINFALL AMOUNTS OF 10-15MM/DAY AND MAXIMA OF 20-35MM/DAY.
ACTIVITY WILL GRADUALLY INCREASE ACROSS THE DOMINICAN
REPUBLIC/HAITI BY 42-48 HRS...WITH RAINFALL AMOUNTS OF 10-15MM/DAY
AND MAXIMA OF 20-35MM. OVER THE SOUTHEAST BAHAMAS/TURKS EXPECT
ACCUMULATION OF 05-10MM/DAY AND MAXIMA OF 15MM/DAY...WHILE OVER
JAMAICA/EASTERN CUBA IT WILL FAVOR ACCUMULATION OF 05-10MM/DAY AND
MAXIMA OF 15-20MM.
 
INVERTED TROUGHS IN THE EASTERLIES FORECAST FROM 00UTC (POSITION
INITIALIZED AT 12Z)

INITIAL      F24   F36   F48   F60   F72   F84
55W (S/23N)  59W   64W   67W   71W   75W   79W
77W (S/16N)  81W   83W   85W   87W   89W   92W
96W (TUTT)   99W   102W  105W  108W  110W  113W

THE WAVE ALONG 55W IS IN PHASE WITH A TUTT INDUCED TROUGH. THIS
WAVE ORIGINATED OVER AFRICA...AND IN THE LAST 24 HRS IT COMBINED
WITH THE INDUCED TROUGH. UNDER INFLUENCE OF THE TUTT SOME OF THE
ENERGY WILL SHEAR TO THE NORTH OF THE VIRGIN ISLANDS...WHILE THE
REST TRACKS TO THE SOUTH OF 14N ACROSS SOUTH AMERICA. THIS IS TO
INTERACT WITH THE EQUATORIAL TROUGH OVER NORTHEAST
VENEZUELA/ORINOCO DELTA REGION TO SUSTAIN RAINFALL AMOUNTS OF
05-15MM/DAY AND MAXIMA OF 20-40MM/DAY. OVER WESTERN
VENEZUELA/SANTANDERES COLOMBIA AND SIERRA DE SANTA MARTA IT WILL
SUSTAIN RAINFALL AMOUNTS OF 10-15MM/DAY AND MAXIMA OF 25-40MM.
THIS WILL EXPAND ACROSS EJE CAFETERO TO THE DARIEN IN PANAMA TO
SUSTAIN RAINFALL AMOUNTS OF 10-15MM/DAY AND MAXIMA OF 25-40MM/DAY.

THE TROPICAL WAVE ALONG 77W WILL REMAIN VERY ACTIVE AS IT ENTERS
COSTA RICA/NICARAGUA BY 36-42 HRS...TO FAVOR RAINFALL AMOUNTS OF
15-30MM/DAY AND MAXIMA OF 40-80MM/DAY. OVER EL SALVADOR-HONDURAS
IT WILL FAVOR RAINFALL AMOUNTS OF 15-30MM/DAY AND MAXIMA OF
40-65MM/DAY...WHILE OVER GUATEMALA/CHIAPAS IN SOUTHERN MEXICO IT
WILL FAVOR RAINFALL AMOUNTS OF 10-20MM/DAY AND MAXIMA OF
25-50MM/DAY.

THE WAVE ALONG 97W IS A TUTT INDUCED PERTURBATION. MOST ACTIVE
CONVECTION IS EXPECTED ALONG THE ITCZ.

ALBERT...NWS (SAINT LUCIA)
CANALES...SMN (HONDURAS)
DAVISON...NCEP (USA)