Prognostic Meteorological Discussion
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FXCA20 KWBC 261829
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TROPICAL DISCUSSION - INTERNATIONAL DESKS
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
229 PM EDT TUE MAY 26 2015

DISCUSSION FROM MAY 26/12 UTC: MID LEVEL RIDGE EXTENDS FROM
CENTRAL MEXICO EASTWARD ACROSS THE GULF-FLORIDA PENINSULA TO A
HIGH OVER THE MID ATLANTIC REGION OF THE USA. MID LEVEL RIDGE
PATTERN IS TO GENERALLY HOLD OVER THE NEXT FEW DAYS...WITH SHORT
WAVE PERTURBATIONS ON THE SOUTHERN STREAM TO LIFT OVER THIS AXIS
AS THEY PULL ACROSS THE SOUTHERN USA. PERSISTENT MID LEVEL RIDGE
PATTERN IS TO GENERALLY FAVOR DRY AND STABLE CONDITIONS ACROSS
NORTHWESTERN MEXICO/BAJA PENINSULA...WITH DIURNAL CONVECTION TO
LIMIT TO PORTIONS OF THE SIERRA MADRE ORIENTAL AND THE SOUTHERN
STATES OF MEXICO. ALONG THE SIERRA MADRE ORIENTAL EXPECTING
RAINFALL AMOUNTS OF 05-10MM/DAY AND MAXIMA OF 15-20MM THROUGH THIS
EVENING. THROUGH THURSDAY THIS DECREASES TO 00-05MM/DAY AND WIDELY
ISOLATED MAXIMA OF 10MM. ON THE SOUTHERN STATES OF MEXICO
EXPECTING RAINFALL AMOUNTS OF 05-10MM/DAY AND MAXIMA OF 15-30MM
THROUGH 15-30MM. ALTHOUGH NORTHERN MEXICO IS TO GENERALLY REMAIN
DRY AND STABLE...AN INCREASE IN CONVECTION IS EXPECTED ALONG THE
RIO BRAVO DURING THE DAY ON THURSDAY AS A STRONG PERTURBATION IN
THE SOUTHERN STREAM MOVES ACROSS TEXAS. THIS IS LIKELY TO TRIGGER
SEVERE THUNDERSTORMS ACROSS NORTHERN COAHUILA...WITH RAINFALL
AMOUNTS OF 15-20MM/DAY AND MAXIMA OF 25-50MM.

EAST OF THIS RIDGE...A TUTT LOW NEAR 28N 59W EXTENDS A TROUGH TO
THE NORTHEAST CARIBBEAN ISLANDS. BROAD TROUGH IS TO PERSIST OVER
THE NEXT FEW DAYS. LATER ON THURSDAY/EARLY FRIDAY MORNING IT WILL
START TO LIFT AS A CELL OF THE SUBEQUATORIAL RIDGE BUILDS ACROSS
THE LESSER ANTILLES TO THE EASTERN CARIBBEAN. ALTHOUGH BEST INFLOW
OF SHORT WAVE ENERGY IS EXPECTED FAR TO THE NORTH...WEAK VORTICES
ON THE SOUTHERN FRINGES OF THIS TROUGH ARE TO GRAZE THE NORTHEAST
CARIBBEAN ISLES FROM TIME TO TIME OVER THE NEXT THREE DAYS. THIS
IS GOING TO BE ENOUGH TO ENHANCE DIURNAL CONVECTION ACROSS
HISPANIOLA-PUERTO RICO...WHERE WE EXPECT RAINFALL AMOUNTS OF
05-10MM/DAY AND MAXIMA OF 15-20MM. OTHER CONVECTION WITH THIS
FEATURE IS EXPECTED AS A TUTT INDUCED PERTURBATION IN THE EASTERLY
TRADES ENTERS THE BASIN. SEE BELOW FOR DETAILS.

FURTHERMORE...UNDER INFLUENCE OF THE PERSISTENT MID/UPPER LEVEL
RIDGE TO THE WEST...THE EASTERN CARIBBEAN TROUGH IS TO GRADUALLY
STRETCH ACROSS THE EASTERN TO THE CENTRAL CARIBBEAN OVER THE NEXT
FEW DAYS. AS IT MEANDERS WEST A SECONDARY LOW IS TO DEVELOP TO THE
SOUTH-SOUTHWEST OF JAMAICA LATER ON WEDNESDAY. THIS IS TO
RETROGRESS FARTHER TO THE NORTHWEST LATER ON THURSDAY. THE
RETROGRESSING LOW IS TO ENHANCE CONVECTION ACROSS JAMAICA. A LULL
IN ACTIVITY...HOWEVER...IS EXPECTED ON WEDNESDAY.
MEANWHILE...EXPECTING RAINFALL AMOUNTS OF 05-10MM/DAY AND MAXIMA
OF 15-30MM THROUGH WEDNESDAY MORNING...WHILE ON THURSDAY EXPECT
RAINFALL AMOUNTS OF 10-15MM/DAY AND MAXIMA OF 20-35MM. THE LOW IS
TO THEN ENHANCE CONVECTION ACROSS THE CAYMAN ISLES AND EASTERN
PORTIONS OF CUBA...WHERE THUNDERSTORMS ARE HIGHLY LIKELY ON
THURSDAY. DURING THAT PERIOD ALSO EXPECTING RAINFALL AMOUNTS OF
10-15MM/DAY AND MAXIMA OF 20-35MM.

AT LOW LEVELS...THE MEANDERING MID LEVEL TROUGH IS TO INDUCED THE
NORTHWARD AMPLIFICATION OF THE PANAMANIAN LOW/TROUGH ACROSS THE
ISTHMUS INTO THE CENTRAL CARIBBEAN ON WEDNESDAY TO THURSDAY. AS
THE TROUGH DEEPENS...THIS IS TO ENHANCE MOIST INFLOW ACROSS THE
WESTERN COASTAL PLAINS OF COLOMBIA INTO THE ANDEAN REGION WHILE
ALSO INDUCING THE NORTHWARD MODULATION OF THE EASTERN PACIFIC ITCZ
INTO NORTHWEST COLOMBIA AND EASTERN PANAMA. ACROSS WESTERN
COLOMBIA TO EASTERN PANAMA EXPECTING RAINFALL AMOUNTS OF
15-20MM/DAY AND MAXIMA OF 25-50MM. THROUGH THURSDAY THIS INCREASES
TO 20-30MM/DAY AND MAXIMA OF 40-80MM. THIS IS TO ALSO FAVOR A
SURGE IN ACTIVITY ACROSS NORTHWEST VENEZUELA...WHERE WE EXPECT
RAINFALL AMOUNTS OF 15-20MM/DAY AND MAXIMA OF 25-50MM LATER ON
THURSDAY. OVER WESTERN PANAMA-COSTA RICA TO SOUTHERN
NICARAGUA...MEANWHILE... EXPECTING RAINFALL AMOUNTS OF 05-10MM/DAY
AND MAXIMA OF 15-20MM ON A DIURNAL PATTERN.

TROPICAL/EASTERLY WAVES INITIALIZED AT 12UTC
INITIAL  24     36     48     60     72     84     96        TYPE
57W      59W    62W    64W    66W    68W    70W    72W    TUTT
INDCD.

THE EASTERN CARIBBEAN TUTT SUSTAINS AN INDUCED TROUGH IN THE LOW
LEVEL EASTERLIES. THIS IS TO SLOWLY MOVE WEST ACROSS THE LEEWARD
ISLES DURING THE DAY ON WEDNESDAY...AND ACROSS PUERTO RICO TO THE
DOMINICAN REPUBLIC LATER ON THURSDAY. MOISTURE IS TO GRADUALLY
SURGE FOLLOWING WAVE PASSAGE...WITH PWAT AMOUNTS OF 45-55MM
EXPECTED TO POOL ACROSS THE EASTERN CARIBBEAN. AS THE MOISTURE
SURGES EXPECTING SCATTERED CONVECTION ACROSS THE NORTHEAST
CARIBBEAN ISLES...WITH RAINFALL AMOUNTS OF 05-10MM/DAY AND MAXIMA
OF 15-30MM ACROSS THE FRENCH-LEEWARD/VIRGIN ISLES. OVER PUERTO
RICO AND HISPANIOLA THIS IS TO THEN FAVOR RAINFALL AMOUNTS OF
10-15MM/DAY AND MAXIMA OF 20-45MM.

THE TROUGH IS TO ALSO INTERACT WITH THE ATLANTIC ITCZ...SUSTAINING
A MOIST SURGE ACROSS THE NORTHERN GUIANAS/ORINOCO DELTA REGION IN
VENEZUELA. EARLY IN THE CYCLE EXPECTING RAINFALL AMOUNTS OF
15-20MM/DAY AND MAXIMA OF 25-50MM. THROUGH THURSDAY THE FOCUS OF
THE CONVECTION SHIFTS FROM NORTHERN GUYANA TO NORTHEAST VENEZUELA
AND THE SOUTHERN WINDWARD ISLES...WITH RAINFALL AMOUNTS OF
10-15MM/DAY AND MAXIMA OF 20-40MM.

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




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