Prognostic Meteorological Discussion
Issued by NWS

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2 3 4
000
FXCA20 KWBC 061822
PMDCA

TROPICAL DISCUSSION - INTERNATIONAL DESKS
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
221 PM EDT WED MAY 06 2015

DISCUSSION FROM MAY 06/12 UTC:  MID/UPPER LEVEL RIDGE CONTINUES TO
DOMINATE FLOW ACROSS MOST OF MEXICO-WESTERN GULF...WITH 500 HPA
HIGH TO THE SOUTHWEST OF COLIMA-MICHOACAN MEXICO TO ANCHOR THIS
AXIS OVER THE NEXT COUPLE OF DAYS. THROUGH FRIDAY EVENING THE HIGH
MOVES INLAND TO 20N 100W. AS IT MOVES INLAND...THIS IS TO
STRENGTHEN THE CAP INVERSION ACROSS MEXICO. MEANWHILE...OVER THE
NEXT COUPLE OF DAYS THE RIDGE ALOFT IS GOING TO BE STRONG ENOUGH
TO DELAY...BUT NOT SUPPRESS...THE ONSET OF DIURNAL CONVECTION.
MOST ACTIVE IS TO CLUSTER ON THE CENTRAL STATES OF
MEXICO...PUEBLA...DF AND SOUTHERN VERACRUZ...WITH RAINFALL AMOUNTS
OF 05-10MM/DAY AND MAXIMA OF 15-20MM. AS THE RIDGE BUILDS INLAND
THIS IS TO THEN DECREASE TO 00-05MM/DAY AND MAXIMA OF 10MM ON
FRIDAY TO SATURDAY. OTHER CONVECTION IS EXPECTED ALONG THE SIERRA
MADRE BETWEEN COAHUILA AND NORTHERN VERACRUZ...WITH RAINFALL
AMOUNTS OF 00-05MM/DAY AND ISOLATED MAXIMA OF 10MM THROUGH
THURSDAY AFTERNOON.

A LONG WAVE TROUGH LIES TO THE EAST OF THE CONTINENTAL
RIDGE...WITH MID LEVEL AXIS SOUTH ACROSS FLORIDA-CUBA TO THE
CENTRAL CARIBBEAN/SOUTHERN CENTRAL AMERICA. THE TROUGH ORIGINATES
ON A CLOSED LOW TO THE NORTH OF THE BAHAMAS...WITH CLOSED
CIRCULATION TO REMAIN FAR TO THE NORTH OVER THE NEXT FEW DAYS. AS
IT MEANDERS OVER FLORIDA/THE WESTERN CARIBBEAN. THIS IS TO ENHANCE
DIURNAL CONVECTION. ACROSS THE CENTRAL-NORTHWEST BAHAMAS IT IS TO
FAVOR RAINFALL AMOUNTS OF 15-30MM/DAY AND MAXIMA OF 40-80MM. DUE
TO POTENTIAL FOR ECHO TRAINING...LOCALIZED MAXIMA IN EXCESS OF
FORECAST GUIDANCE IS HIGHLY LIKELY. THROUGH THURSDAY THIS
DECREASES TO 05-10MM/DAY AND MAXIMA OF 15-20MM...WITH ISOLATED
CONVECTION POSSIBLE ON FRIDAY. OVER CUBA...IN INTERACTION WITH
DIURNAL HEATING...IT IS TO FAVOR SCATTERED CONVECTION ACROSS
CENTRAL PORTIONS OF THE ISLAND WITH ACCUMULATION OF 10-15MM/DAY
AND MAXIMA OF 20-40MM THROUGH THURSDAY MORNING. THIS THEN
DECREASES TO 05-10MM/DAY AND MAXIMA OF 15-30MM ON THURSDAY TO
FRIDAY. THE TROUGH ALOFT IS TO ENHANCE CONVECTION ACROSS NORTHEAST
NICARAGUA AND HONDURAS...BUT WE DO NOT EXPECT IT TO BE AS
INTENSE/ACTIVE AS WHAT THE GFS SUGGESTS. IN THIS AREA EXPECTING
RAINFALL AMOUNTS OF 00-05MM/DAY AND MAXIMA OF 10MM. FARTHER
SOUTH...DIURNAL CONVECTION ACROSS SOUTHERN NICARAGUA...COSTA RICA
AND EL SALVADOR IS TO RESULT IN RAINFALL AMOUNTS OF 05-10MM/DAY
AND MAXIMA OF 15MM. OVER COLOMBIA...CONVECTION ALONG THE
ANDES/WESTERN PLAINS IS TO FAVOR RAINFALL AMOUNTS OF 05-10MM/DAY
AND ISOLATED MAXIMA OF 15-30MM. HIGHER AMOUNTS ARE EXPECTED ACROSS
AMAZONIA AND THE EASTERN PLAINS...WITH CONVECTION TO CLUSTER ALONG
THE NEAR EQUATORIAL TROUGH TO FAVOR RAINFALL AMOUNTS OF
10-15MM/DAY AND MAXIMA OF 20-40MM.

A RIDGE LIES TO THE EAST OF THE CARIBBEAN TROUGH...WITH MID LEVEL
AXIS TO ANCHOR ON A MEANDERING HIGH NEAR 20N 55W. AS IT MEANDERS
OVER THE TROPICAL ATLANTIC-EASTERN CARIBBEAN THIS FAVORS A STRONG
CAP INVERSION ACROSS THE ISLAND CHAIN-PUERTO RICO AND HISPANIOLA.
AT LOW LEVELS THIS SUSTAINS A BROAD RIDGE ACROSS THE CENTRAL
ATLANTIC INTO THE EASTERN CARIBBEAN/NORTHERN GUIANAS-NORTHEAST
VENEZUELA. IN A TIGHT GRADIENT...TRADE WIND EASTERLIES ARE SURGING
ACROSS THE TROPICAL ATLANTIC-LESSER ANTILLES AND THE CENTRAL
CARIBBEAN. THE STRONG FLOW IS ADVECTING DUST FROM THE SAHARA INTO
THE EASTERN CARIBBEAN...FORECAST TO ADVECT ACROSS THE CENTRAL
CARIBBEAN THROUGH MIDDAY ON WEDNESDAY. STRONG MID/LOW LEVEL CAP
INVERSION AND LOW LEVEL DUSTY CONDITIONS TRANSLATE INTO DRY AND
STABLE CONDITIONS ACROSS THE ISLAND CHAIN-PUERTO RICO/EASTERN
HISPANIOLA...THE NORTHERN GUIANAS AND MOST OF VENEZUELA. OVER
SOUTH AMERICA MOST ACTIVE CONVECTION IS TO CLUSTER ALONG THE NEAR
EQUATORIAL TROUGH AS IT MEANDERS OVER THE SOUTHERN
GUIANAS-AMAZONIA IN VENEZUELA TO COLOMBIA. ACROSS THE SOUTHERN
GUIANAS EXPECTING RAINFALL AMOUNTS OF 05-10MM/DAY AND MAXIMA OF
15-30MM. THROUGH FRIDAY THIS DECREASES TO 05-10MM/DAY AND MAXIMA
OF 15-20MM OVER SOUTHERN VENEZUELA AND COLOMBIA EXPECTING RAINFALL
AMOUNTS OF 10-15MM/DAY AND MAXIMA OF 20-40MM.

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

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




USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.