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Tropical Discussion
 
(Caution: Version displayed is not the latest version. - Issued 1919Z Feb 26, 2015)
 
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TROPICAL DISCUSSION - INTERNATIONAL DESKS
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
219 PM EST THU FEB 26 2015

DISCUSSION FROM FEBRUARY 26/00UTC: BROAD MID/UPPER LEVEL TROUGH
EXTENDS ACROSS NORTH AMERICA. THROUGH SATURDAY EVENING THE TROUGH
IS TO GRADUALLY PULL AS A RIDGE BUILDS TO THE SOUTH.
MEANWHILE...THE ASSOCIATED SURFACE FRONT IS TO MEANDER OVER THE
NORTHWEST BAHAMAS-SOUTH FLORIDA/WESTERN TIP OF CUBA-NORTHERN
YUCATAN/SOUTHERN STATES OF MEXICO EARLY IN THE CYCLE. THE FRONT IS
TO THEN REMAIN NEARLY STATIONARY THROUGH FRIDAY EVENING...WITH
TRAILING END OVER THE GULF TO THEN RETROGRESS ACROSS FLORIDA TO
THE NORTHERN GULF/NORTHEAST MEXICO-SOUTH TEXAS DURING THE DAY ON
SATURDAY. AS IT ENTERS SOUTHERN MEXICO EARLY IN THE CYCLE THIS IS
TO SUSTAIN RAINFALL AMOUNTS OF 05-10MM/DAY AND MAXIMA OF 15MM.
OVER VERACRUZ-OAXACA-CHIAPAS TO CENTRAL GUATEMALA THIS INCREASES
TO 05-10MM/DAY AND MAXIMA OF 15-25MM ON FRIDAY. ACROSS THE
NORTHWEST BAHAMAS THIS IS TO THEN FAVOR RAINFALL AMOUNTS OF
00-05MM/DAY AND MAXIMA OF 10MM THROUGH FRIDAY EVENING. PREFRONTAL
CONVECTION OVER WESTERN CUBA WILL RESULT IN RAINFALL AMOUNTS OF
05-10MM/DAY AND MAXIMA OF 15MM EARLY ON FRIDAY MORNING.

SOUTH OF THIS TROUGH...OVER THE CARIBBEAN BASIN...A MID/UPPER
LEVEL RIDGE DOMINATES FLOW ACROSS THE CARIBBEAN-CENTRAL AMERICA.
EARLY IN THE CYCLE THE RIDGE IS TO ANCHOR ON A 500 HPA HIGH TO THE
NORTH OF PUERTO RICO AND THE VIRGIN ISLES. THROUGH SATURDAY
MORNING THE HIGH RELOCATES TO HAITI...WHILE THE RIDGE BUILDS WEST
ACROSS NORTHERN CENTRAL AMERICA TO THE SOUTHERN/ CENTRAL STATES OF
MEXICO. AS THE RIDGE BUILDS WEST...THIS IS TO STRENGTHEN THE TRADE
WINDS CAP ACROSS THE SOUTHERN STATES OF MEXICO...WHILE OVER
CENTRAL AMERICA-ISLANDS OF THE CARIBBEAN THE STRONG CAP INVERSION
IS TO PERSIST OVER THE NEXT FEW DAYS.

AT LOW LEVELS...AN EAST-TO-WEST RIDGE EXTENDS ACROSS THE ATLANTIC
TO THE NORTHERN CARIBBEAN/GULF OF MEXICO. THIS RIDGE IS ALSO
FORECAST TO SLOWLY BUILD WEST...WITH AXIS TO AMPLIFY ACROSS THE
FLORIDA PENINSULA TO THE GULF OF MEXICO LATER ON SATURDAY. AS THE
RIDGE BUILD...AND GRADIENT TIGHTENS... THE EASTERLY TRADES OVER
THE BASIN ARE EXPECTED TO SURGE. THE 850 HPA WINDS OVER THE
EASTERN CARIBBEAN ARE TO INCREASE TO 30-35KT EARLY IN THE
CYCLE...THIS QUICKLY EXPANDS INTO THE VIRGIN ISLES/NORTHEAST
CARIBBEAN... THEN WEST ACROSS THE CENTRAL CARIBBEAN DURING THE DAY
ON FRIDAY. STRONG WINDS OF 35-45KT ARE THEN EXPECTED ACROSS
CENTRAL AMERICA TO THE EASTERN PACIFIC EARLY ON SATURDAY MORNING.
AHEAD OF THIS WIND SURGE...LOW LEVEL MOISTURE IS FORECAST TO
CONVERGENCE TO THE WEST...AND THIS IS LIKELY TO FAVOR AN INCREASE
IN CONVECTION OVER THE LESSER ANTILLES AND PUERTO RICO DURING THE
DAY ON THURSDAY...WITH RAINFALL AMOUNTS OF 00-05MM/DAY AND MAXIMA
OF 10MM. THIS REACHES JAMAICA BY MIDMORNING ON FRIDAY...TO FAVOR
RAINFALL AMOUNTS OF 05-10MM/DAY AND MAXIMA OF 15MM. SIMILAR
AMOUNTS ARE EXPECTED OVER NICARAGUA ON SATURDAY. STRONG EASTERLY
TRADES ARE TO THEN FAVOR GENERATION OF TRADE WIND SHOWERS AND
STREAMERS THAT ARE TO AFFECT THE ISLAND CHAIN-PUERTO RICO THROUGH
DAY 04.

EAST OF THE CARIBBEAN RIDGE...AT 250 HPA...A TUTT EXTENDS TO THE
SOUTHWEST ALONG 23N 40W...20N 50W...WINDWARD ISLES TO NORTHEAST
VENEZUELA/NORTHERN GUIANAS. UNDER INFLUENCE OF THE RIDGE TO THE
WEST...TROUGH ALOFT IS TO SHEAR A VORTEX THAT RETROGRESSES ACROSS
VENEZUELA DURING THE DAY ON FRIDAY...INTO COLOMBIA EARLY ON
SATURDAY. THE TROUGH ALOFT SUSTAINS AN INDUCED/INVERTED TROUGH IN
THE EASTERLY TRADES. THIS IS TO MOVE IN-TANDEM WITH THE UPPER
LEVEL PERTURBATION. EARLY IN THE CYCLE THIS IS TO ENHANCE
CONVECTION ACROSS GUYANA-EASTERN VENEZUELA TO TRINIDAD/TOBAGO...TO
FAVOR RAINFALL AMOUNTS OF 15-20MM/DAY AND MAXIMA OF 25-50MM.
CONVECTION IS TO THEN BUILD WEST ACROSS CENTRAL/SOUTHERN
VENEZUELA...TO FAVOR RAINFALL AMOUNTS OF 10-15MM/DAY AND MAXIMA OF
20-40MM. ALONG THE COAST OF VENEZUELA TO THE ABC ISLANDS A MOIST
PLUME TO THE NORTH IS TO THEN FAVOR RAINFALL AMOUNTS OF
05-10MM/DAY AND MAXIMA OF 15MM DURING THE DAY ON FRIDAY. LATER IN
THE CYCLE THE TROUGH IS TO ENHANCE CONVECTION ACROSS NORTHWEST
VENEZUELA TO SANTANDERES IN COLOMBIA...WHERE WE EXPECT RAINFALL
AMOUNTS OF 10-15MM/DAY AND MAXIMA OF 20-30MM.

THE EASTERN PACIFIC ITCZ MEANDERS TO SOUTHWEST COLOMBIA...WHERE IT
IS TO REMAIN OVER THE NEXT FEW DAYS. THIS IS INTERACTING WITH AN
ILL ORGANIZED TROUGH ALONG THE WEST COAST OF COLOMBIA...ENHANCING
MOISTURE CONVERGENCE ALONG THE WESTERN PLAINS AND ANDEAN REGION.
IN THIS AREA EXPECTING DIURNAL CONVECTION TO SUSTAIN RAINFALL
AMOUNTS OF 05-10MM/DAY IN ISOLATED TO SCATTERED CONVECTION...WITH
WIDELY ISOLATED MAXIMA OF 15-20MM/DAY. AS THE TRADES INTENSIFY
ACROSS THE CARIBBEAN-CENTRAL AMERICA...A GRADUAL DRYING TREND IS
EXPECTED LATER DURING THE WEEKEND...WITH RAINFALL AMOUNTS TO
DECREASE TO 00-05MM/DAY AND WIDELY ISOLATED MAXIMA OF 10MM. HIGHER
AMOUNTS...HOWEVER...ARE TO PERSIST TO THE SOUTHWEST INTO THE
CAUCA/CAUCA VALLEY...WITH RAINFALL AMOUNTS OF 10-15MM/DAY AND
MAXIMA OF 20-30MM. THROUGH SUNDAY THE MAXIMA IN THIS AREA
INCREASES TO 20-40MM.

TROPICAL/EASTERLY WAVES INITIALIZED AT 12UTC
INITIAL  24     36     48     60     72     84     96     TYPE
NONE

CRAIG...TTMS (TRINIDAD AND TOBAGO)
NANDA...MDS (SURINAME)
DAVISON...WPC (USA)