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Tropical Discussion
 
(Caution: Version displayed is not the latest version. - Issued 1825Z May 24, 2018)
 
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TROPICAL DISCUSSION - INTERNATIONAL DESKS
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
225 PM EDT THU MAY 24 2018

TROPICAL DISCUSSION FROM MAY 24/12 UTC: A MEANDERING 500 HPA HIGH
OVER SOUTHWEST MEXICO ANCHORS A RIDGE THAT EXTENDS NORTH INTO THE
SOUTHWEST USA. AS THE RIDGE HOLDS...IT FAVORS THE SOUTHWARD
AMPLIFICATION OF A TROUGH ACROSS THE CENTRAL GULF OF MEXICO TO THE
YUCATAN/WESTERN CARIBBEAN DURING THE DAY TODAY. ON FRIDAY THE
TROUGH BOTTOMS OUT OVER SOUTHERN GUATEMALA/HONDURAS...WHERE IT IS
TO REMAIN THROUGH THE WEEKEND. AT LOW LEVELS...THIS SUSTAINS A
SURFACE LOW OVER QUINTANA ROO IN THE YUCATAN AND A TROUGH THAT
EXTENDS NORTH ALONG 88W BETWEEN HONDURAS AND THE EASTERN GULF OF
MEXICO. THE LOW/TROUGH IS ENHANCING MOISTURE CONVERGENCE OVER THE
NORTHWEST CARIBBEAN-WESTERN CUBA WHILE ALSO ADVECTING DEEP
TROPICAL MOISTURE ACROSS QUINTANA ROO IN THE YUCATAN. THE GFS IS
NOW IN CLOSER AGREEMENT WITH THE ECMWF ON HOW THE SURFACE LOW IS
GOING TO EVOLVE DURING THE SHORT RANGE PERIOD...WITH THE CLOSED
LOW LIFTING ACROSS THE YUCATAN CHANEL DURING THE MORNING HOURS ON
SATURDAY. THE UKMET...ALTHOUGH IT FOLLOWS A SIMILAR
TRAJECTORY...IT IS MUCH SLOWER THAN THE OTHER MODELS. THE NHC IS
MONITORING THIS SYSTEM FOR PROBABLE TROPICAL CYCLONE FORMING
DURING THE NEXT FEW DAYS. MEANWHILE...OVER WESTERN CUBA THIS IS TO
SUSTAIN RAINFALL AMOUNTS OF 50-100MM/DAY AND MAXIMA OF
150-250MM/DAY THROUGH SATURDAY MORNING. ON SATURDAY TO SUNDAY
EXPECTING ADDITIONAL RAINFALL AMOUNTS OF 25-50MM/DAY AND MAXIMA OF
100-150MM. IN THIS AREA...TOTAL RAINFALL AMOUNTS FOR THE NEXT
THREE DAYS ARE TO RANGE BETWEEN 500-750MM. OVER QUINTANA ROO IN
THE YUCATAN ALSO EXPECTING HEAVY RAINFALL AMOUNTS DURING THE NEXT
TWO DAYS...WITH ACCUMULATION OF 20-40MM/DAY AND MAXIMA OF 50-100MM
THROUGH FRIDAY MORNING...WHILE ON FRIDAY TO SATURDAY EXPECTING
ACCUMULATION OF 50-100MM/DAY AND MAXIMA OF 150-250MM. ACROSS
NORTHERN BELIZE INITIALLY EXPECTING ACCUMULATION OF 20-40MM/DAY
AND MAXIMA OF 50-100MM. ON FRIDAY THIS DECREASES TO 10-15MM/DAY
AND MAXIMA OF 20-45MM...WHILE ON SATURDAY-SUNDAY THE MAXIMA PEAKS
AT 15-20MM. OVER THE CAYMAN ISLES-CENTRAL CUBA FEEDER BAND
CONVERGENCE WILL FAVOR RAINFALL AMOUNTS OF 15-20MM/DAY AND MAXIMA
OF 25-50MM. ON FRIDAY THIS INCREASES TO 15-20MM/DAY AND MAXIMA OF
30-60MM...WHILE ON SATURDAY EXPECTING ACCUMULATION OF 10-15MM/DAY
AND MAXIMA OF 20-35MM. OVER JAMAICA EXPECTING RAINFALL AMOUNTS OF
05-10MM/DAY AND MAXIMA OF 15MM OVER THE NEXT COUPLE OF
DAYS...INCREASING TO 10-15MM/DAY AND MAXIMA OF 20-35MM ON SATURDAY.

UNDER INFLUENCE OF THE DEEP MID/UPPER LEVEL TROUGH OVER THE
GULF/WESTERN CARIBBEAN AND THE INDUCED LOW LEVEL TROUGH OVER
NORTHERN CENTRAL AMERICA...THE EASTERN PACIFIC ITCZ REMAINS NORTH
OF ITS CLIMATOLOGICAL POSITION...WITH AXIS MEANDERING ACROSS
NICARAGUA TO THE CENTRAL CARIBBEAN. LATER THIS AFTERNOON....AS THE
LOW LEVEL CYCLONIC CIRCULATION OVER THE YUCATAN STRENGTHENS...A
LONG FETCH WEST-SOUTHWEST FLOW IS TO ESTABLISH ACROSS THE EASTERN
PACIFIC TO WESTERN NICARAGUA-SOUTHEAST HONDURAS/EL SALVADOR. THIS
WILL ENHANCE MOISTURE TRANSPORT AND CONVERGENCE ALONG THE
CONTINENTAL DIVIDE BETWEEN WESTERN NICARAGUA AND EL
SALVADOR/SOUTHERN HONDURAS. IN THIS AREA EXPECTING RAINFALL
AMOUNTS OF 20-30MM/DAY AND MAXIMA OF 50-100MM/DAY. OVER NORTHEAST
HONDURAS/NICARAGUA EXPECTING ACCUMULATION OF 10-15MM/DAY AND
MAXIMA OF 20-35MM/DAY. OVER COSTA RICA/SOUTHERN NICARAGUA...IN A
MOIST WESTERLY FLOW...INITIALLY EXPECTING RAINFALL AMOUNTS OF
15-20MM/DAY AND MAXIMA OF 30-60MM. ON FRIDAY THIS DECREASES TO
10-15MM/DAY AND MAXIMA OF 20-40MM...SURGING ON SATURDAY TO
20-30MM/DAY AND MAXIMA OF 50-100MM. OVER NORTHERN
COLOMBIA/NORTHWEST VENEZUELA AND PANAMA EXPECTING RAINFALL AMOUNTS
OF 10-15MM/DAY AND MAXIMA OF 20-35MM. OVER EASTERN
COLOMBIA-SOUTHERN VENEZUELA...MEANWHILE...EXPECTING RAINFALL
AMOUNTS OF 15-20MM/DAY AND MAXIMA OF 30-60MM/DAY.

FARTHER EAST...AT MID LEVELS...A LOW AMPLITUDE RIDGE EXTENDS OVER
THE EASTERN CARIBBEAN...WHILE A TUTT TO THE EAST IS QUICKLY
LIFTING ACROSS THE CENTRAL ATLANTIC. AS AFOREMENTIONED TROUGH
DEEPENS ACROSS THE GULF OF MEXICO TO THE WESTERN CARIBBEAN THIS IS
TO THEN FAVOR THE NORTHWARD AMPLIFICATION OF THE RIDGE ACROSS THE
BAHAMAS-WESTERN ATLANTIC...WITH AXIS TO REACH MAXIMUM AMPLITUDE
DURING THE WEEKEND. THE BUILDING RIDGE IS TO SUSTAIN AN ELEVATED
TRADE WINDS INVERSION THAT IS TO CAP MOISTURE OVER THE EASTERN
CARIBBEAN TO ATMOSPHERE BELOW 650/700 HPA. AT LOW LEVELS...BROAD
CELL OF THE SUBTROPICAL RIDGE IS TO DOMINATE THE FLOW ACROSS THE
ATLANTIC TO THE EASTERN/CENTRAL CARIBBEAN. OVER THE EASTERN
CARIBBEAN...AT 850 HPA THIS IS TO FAVOR AN EAST-SOUTHEAST FLOW
WITH WINDS OF 10-15KT...WHILE OVER THE SOUTHERN CARIBBEAN
EXPECTING WINDS OF 25-30KT. THIS IS TO ENHANCE MOISTURE TRANSPORT
ACROSS THE BASIN...WITH MOISTURE TO GRADUALLY POOL OVER PUERTO
RICO-VIRGIN ISLES AND THE DOMINICAN REPUBLIC. IN THIS AREA
EXPECTING RAINFALL AMOUNTS OF 10-15MM/DAY AND MAXIMA OF 20-35MM.
THROUGH SUNDAY IT INCREASES TO 10-15MM/DAY AND MAXIMA OF 20-45MM.

CELL OF THE SUBEQUATORIAL RIDGE TO THE SOUTH DOMINATES THE UPPER
LEVEL FLOW FROM THE TROPICAL ATLANTIC WESTWARD TO THE
GUIANAS/SOUTHERN VENEZUELA. THIS IS VENTING CONVECTION ALONG THE
ITCZ/NEAR EQUATORIAL TROUGH. ACROSS FRENCH GUIANA-SURINAME
EXPECTING RAINFALL AMOUNTS OF 10-15MM/DAY AND MAXIMA OF 20-30MM
THROUGH FRIDAY MORNING...WHILE ON FRIDAY-SATURDAY EXPECTING
ACCUMULATION OF 05-10MM/DAY AND MAXIMA OF 15-20MM. ON
SATURDAY-SUNDAY THIS INCREASES TO 15-20MM/DAY AND MAXIMA OF
30-60MM. ACROSS GUYANA TO EASTERN VENEZUELA THIS WILL INCREASE
THROUGH FRIDAY TO 15-20MM/DAY AND MAXIMA OF 30-60MM.

TROPICAL/EASTERLY WAVES/TRADE WIND SURGES INITIALIZED AT 12UTC:
INITIAL 24    36    48    60    72    84    96        TYPE      
SOF
49W     52W   55W   57W   60W   62W   65W   68W        TW       
16N
77W     78W   80W   82W   83W   DISSIPATES             TW       
17N
88W     88W   88W   87W   88W   87W   88W   88W     TUTT INDCD  
28N

TROPICAL WAVE ALONG 49W AND SOUTH OF 16N IS TO TRIGGER SCATTERED
CONVECTION ACROSS FRENCH GUIANA-SURINAME...WITH RAINFALL AMOUNTS
OF 10-15MM/DAY AND MAXIMA OF 20-30MM. ON FRIDAY...AS IT BUILDS
ACROSS GUYANA... THIS INCREASES TO 15-20MM/DAY AND MAXIMA OF
30-60MM. ON SATURDAY THIS IS TO TRIGGER SCATTERED CONVECTION
ACROSS EASTERN-CENTRAL VENEZUELA...WITH ACCUMULATION OF
15-20MM/DAY AND MAXIMA OF 30-60MM. OVER THE LESSER ANTILLES THIS
IS TO TRIGGER RAINFALL AMOUNTS OF 05-10MM/DAY AND MAXIMA OF
15-20MM. ON SUNDAY IT IS TO SUSTAIN A SURGE IN ACTIVITY ACROSS
PUERTO RICO WITH ACCUMULATION OF 10-15MM/DAY AND MAXIMA OF 20-45MM.

A TROPICAL WAVE ALONG 77W AND SOUTH OF 17N IS FORECAST TO
DISSIPATE ON SATURDAY AS IT MERGES WITH THE TUTT INDUCED
PERTURBATION TO THE WEST. MEANWHILE...OVER NORTHERN COLOMBIA TO
EASTERN PANAMA EXPECTING ACCUMULATION OF 10-15MM/DAY AND MAXIMA OF
20-35MM ON THURSDAY TO FRIDAY...WHILE ACROSS COSTA RICA THIS IS TO
TRIGGER RAINFALL AMOUNTS OF 10-15MM/DAY AND MAXIMA OF 20-40MM ON
FRIDAY TO SATURDAY. MOST INTENSE TO CLUSTER ALONG THE CONTINENTAL
DIVIDE.

THE TUTT OVER THE GULF/WESTERN CARIBBEAN SUSTAINS AN INDUCED
TROUGH IN THE EASTERLY TRADES WITH AXIS ALONG 88W TO 28N. MOST
ACTIVE CONVECTION WITH THIS FEATURE IS EXPECTED OVER WESTERN
CUBA-NORTHEAST YUCATAN AND ALONG THE CONTINENTAL DIVIDE BETWEEN EL
SALVADOR/HONDURAS AND WESTERN NICARAGUA. SEE ABOVE FOR DETAILS.

HUDSON...MS (JAMAICA)
NIXON...BDM (THE BAHAMAS)
DAVISON...WPC (USA)