Prognostic Meteorological Discussion
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FXCA20 KWBC 301857
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TROPICAL DISCUSSION - INTERNATIONAL DESKS
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
157 PM EST FRI JAN 30 2015

DISCUSSION FROM JANUARY 30/00UTC: WEST OVER THE DOMAIN...A DEEP
MID LEVEL TROUGH ON THE SOUTHERN STREAM EXTENDS ACROSS BAJA
CALIFORNIA TO THE TROPICAL PACIFIC ALONG 105W/106W. THIS TROUGH IS
INTERACTING WITH THE ITCZ TO THE SOUTH...DRAWING DEEP MOISTURE
NORTH. ALSO...THE TROUGH ALOFT CONTINUES TO PRESS AGAINST A RIDGE
TO THE EAST...AND IN THIS PROCESS IT IS SHEARING SHORT WAVE ENERGY
ACROSS THE NORTHWEST STATES OF MEXICO. STRONG CYCLONIC VORTICITY
ADVECTION AND TOPOGRAPHICAL FORCING WILL COMBINE IN SUPPORT OF
AREAS OF ORGANIZED CONVECTION. ACROSS NORTHWEST MEXICO EXPECTING
RAINFALL AMOUNTS OF 15-20MM/DAY AND MAXIMA OF 25-50MM THROUGH
SATURDAY MORNING. BUT LATER IN THE DAY THE FOCUS OF THE CONVECTION
SHIFTS TO SONORA MEXICO...WHERE WE ALSO EXPECT RAINFALL AMOUNTS OF
15-20MM/DAY AND MAXIMA OF 25-50MM. OTHER CONVECTION IS TO THEN
BUILD EAST ACROSS THE NORTH-CENTRAL TO NORTHEASTERN STATES OF
MEXICO...WITH ACCUMULATION OF 00-05MM/DAY AND MAXIMA OF 10MM.

AS THE MID/UPPER LEVEL TROUGH PRESSES AGAINST THE RIDGE TO THE
EAST...THE RIDGE IS TO GRADUALLY YIELD. EARLY IN THE CYCLE IT IS
TO CONFINE TO MEXICO-CENTRAL AMERICA AND THE GULF OF MEXICO. BUT
THROUGH SATURDAY EVENING/EARLY SUNDAY MORNING THE RIDGE BUILDS
EAST ACROSS THE CARIBBEAN BASIN/NORTHERN SOUTH AMERICA. STRONG
MID/UPPER LEVEL RIDGE PATTERN IS THEN EXPECTED TO HOLD BEYOND DAY
05. AS THE RIDGE MOVES TO THE EAST...CAP INVERSION OVER MEXICO IS
TO WEAKEN. HOWEVER...ACROSS THE CARIBBEAN BASIN IT IS TO
STRENGTHEN.

ALSO AT MID/UPPER LEVELS...A POLAR TROUGH OVER THE WESTERN NORTH
ATLANTIC CONTINUES TO LIFT TO THE NORTHEAST AS ANOTHER TROUGH
DEEPENS TO THE WEST ACROSS THE EASTERN USA TO THE WESTERN
ATLANTIC. THE FORMER SUSTAINS A WANING FRONT TO THE NORTH OF
HISPANIOLA INTO THE SOUTHEAST BAHAMAS/EASTERN CUBA-NORTHWEST
CARIBBEAN...AND A PREFRONTAL SHEAR LINE THAT MEANDERS BETWEEN
PUERTO RICO AND THE USVI. THESE FEATURES ARE TO WEAKEN DURING THE
NEXT 36 HRS. ACROSS NORTHERN HISPANIOLA...MEANWHILE...EXPECTING
RAINFALL AMOUNTS OF 05-10MM/DAY AND MAXIMA OF 15-25MM...WHILE OVER
PUERTO RICO AND THE VI EXPECT RAINFALL AMOUNTS OF 00-05MM/DAY AND
MAXIMA OF 10MM.

THE NEXT TROUGH IS FORECAST TO MOVE OFF THE EASTERN USA TO THE
WESTERN ATLANTIC THROUGH FRIDAY EVENING...AND IT IS TO MEANDER
EAST ACROSS 60W LATER ON SATURDAY. THIS TROUGH LACKS THE AMPLITUDE
OF THE FORMER...WITH AXIS EXPECTED TO BOTTOM OUT TO THE NORTH OF
25N/26N EARLY IN THE CYCLE. THE ASSOCIATED FRONT REACHES THE
NORTHWEST BAHAMAS LATER TODAY/EARLY SATURDAY MORNING...AND DURING
THE EVENING HOURS ON SATURDAY THE FRONT MOVES TO THE CENTRAL
BAHAMAS-STRAITS OF FLORIDA TO THE NORTHERN GULF/SOUTHERN USA. A
POLAR RIDGE IS TO THEN ROLL ACROSS THE SOUTHEAST USA TO THE
WESTERN ATLANTIC LATER ON SATURDAY. THIS DISPLACES THE FRONT SOUTH
ALONG 19N/20N EARLY ON SUNDAY...WITH AXIS TO MEANDER WEST ACROSS
NORTH OF HISPANIOLA-BAHAMAS TO THE NORTHEAST GULF. THIS IS TO THEN
REMAIN NEARLY STATIONARY THROUGH SUNDAY EVENING...FRONTOLIZING ON
MONDAY. FURTHERMORE...THE BUILDING POLAR RIDGE TO THE WEST IS TO
TRIGGER A PREFRONTAL SHEAR LINE ACROSS THE BASIN. THIS IS TO FORM
LATER ON FRIDAY/EARLY SATURDAY MORNING...WITH AXIS ACROSS
HISPANIOLA TO THE CENTRAL CARIBBEAN/COSTA RICA-SOUTHERN NICARAGUA.
WINDS OF 20-25KT ARE TO ACCOMPANY THIS FEATURE AS IT PULLS ACROSS
THE BASIN. LATER ON SATURDAY IT MOVES ACROSS PUERTO RICO-VIRGIN
ISLES WHILE TRAILING TO THE SOUTHERN  CARIBBEAN...REACHING THE
NORTHERN LEEWARD ISLES ON SUNDAY MORNING. LATER ON SUNDAY IT MOVES
TO THE FRENCH ISLES...TO THEN  BECOME ILL DEFINED. AS THE FRONT
MOVES OVER THE BAHAMAS IT IS TO FAVOR RAINFALL AMOUNTS OF
00-05MM/DAY AND MAXIMA OF 10MM. ACROSS NORTHERN HISPANIOLA AND
PUERTO RICO THE SHEAR LINE IS TO SUSTAIN RAINFALL AMOUNTS OF
05-10MM/DAY AND MAXIMA OF 15-25MM. THIS DECREASES TO 05-10MM/DAY
AND MAXIMA OF 15MM LATER ON SUNDAY. OVER COSTA RICA/SOUTHERN
NICARAGUA-WESTERN PANAMA...THE SHEAR LINE IS TO SUSTAIN RAINFALL
AMOUNTS OF 05-10MM/DAY...WITH MAXIMA OF 15MM.

OVER WESTERN COLOMBIA...AN ILL ORGANIZED PANAMANIAN LOW IS TO
ANCHOR A SHORT WAVE TROUGH ALONG THE COASTAL PLAINS/COASTAL
WATERS. THIS IS TO ENHANCE LOW LEVEL CONVERGENCE...WITH MOISTURE
EXPECTED TO SURGE THROUGH SATURDAY EVENING. INFLOW OF MOISTURE
WILL FEED DIURNAL CONVECTION ALONG THE WEST COAST/ANDEAN REGION.
INITIALLY EXPECTING RAINFALL AMOUNTS OF 00-05MM/DAY AND MAXIMA OF
10MM. THIS INCREASES TO 05-10MM/DAY AND MAXIMA OF 15MM LATER ON
SATURDAY. ON THE CAUCA VALLEY TO THE SOUTHWEST...HIGHER AMOUNTS
ARE EXPECTED THROUGH SATURDAY EVENING WITH RAINFALL AMOUNTS OF
05-10MM/DAY AND MAXIMA OF 15-30MM. OVER AMAZONIA IN SOUTHERN
COLOMBIA...A SURGE IN ACTIVITY IS EXPECTED ON FRIDAY-SUNDAY
MORNING...WITH DAILY RAINFALL AMOUNTS OF 15-20MM/DAY AND MAXIMA OF
30-60MM. MAXIMA ON SUNDAY DECREASES TO 20-35MM.

THE GUIANAS...MEANWHILE...REMAIN UNDER INFLUENCE OF A SOUTHERN
HEMISPHERE/ CROSS EQUATORIAL TROUGH. THROUGH THIS EVENING THE TUTT
LOW IS TO RELOCATE TO 10S 48W...WITH BROAD TROUGH ACROSS NORTHERN
BRASIL TO SOUTHERN VENEZUELA AND THE GUIANAS. THIS TROUGH IS
FORECAST TO WEAKEN THROUGH SATURDAY EVENING. MEANWHILE...IT IS TO
ENHANCE CONVECTIVE DEVELOPMENT ACROSS THE NORTHERN GUIANAS TO
FAVOR RAINFALL AMOUNTS OF 05-10MM/DAY AND MAXIMA OF 15-20MM. THIS
DECREASES TO 00-05MM/DAY AND MAXIMA OF 10MM THROUGH SUNDAY
EVENING.

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

JN BAPTISTE...MS (SAINT LUCIA)
NANDA...MDS (SURINAME)
DAVISON...WPC (USA)
$$




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