Prognostic Meteorological Discussion
Issued by NWS

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6
000
FXCA20 KWBC 031927
PMDCA

TROPICAL DISCUSSION - INTERNATIONAL DESKS
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
227 PM EST TUE MAR 03 2015

DISCUSSION FROM MARCH 03/00UTC: A MID LEVEL LOW ON THE SOUTHERN
STREAM MEANDERS OFF THE COAST OF SOUTHERN CALIFORNIA/NORTHERN BAJA
PENINSULA. THIS EXTENDS A SHORT WAVE TROUGH TO THE
SOUTH-SOUTHWEST. THE DEEP TROUGH IS DRAWING ITCZ MOISTURE
NORTHWARD ACROSS THE BAJA PENINSULA/NORTHWEST STATES OF MEXICO.
THE TROUGH PATTERN IS TO SLOWLY EVOLVE TROUGH WEDNESDAY MORNING
WHILE GRADUALLY MERGING INTO AN AMPLIFYING POLAR TROUGH TO THE
NORTH. MEANWHILE...THIS IS TO SUSTAIN ORGANIZED CONVECTION ALONG
THE SIERRA MADRE OCCIDENTAL...TO AFFECT PORTIONS OF
CHIHUAHUA-SINALOA AND SONORA. IN THIS AREA EXPECTING RAINFALL
AMOUNTS OF 10-15MM/DAY AND MAXIMA OF 20-45MM THROUGH WEDNESDAY
MORNING...AND 05-10MM/DAY AND MAXIMA OF 15MM LATER IN THE DAY.

AMPLIFYING POLAR TROUGH MOVES ACROSS THE MIDWESTERN USA EARLY ON
WEDNESDAY. THIS IS TO QUICKLY MIGRATE ACROSS THE USA WHILE LIFTING
OVER A RIDGE TO THE SOUTH. THE PROGRESSIVE TROUGH IS TO SUSTAIN A
FRONT ACROSS NORTH AMERICA... WITH AXIS ACROSS TEXAS TO THE RIO
BRAVO EARLY ON THURSDAY MORNING. LATER ON THURSDAY THE FRONT MOVES
ACROSS THE SOUTHERN USA TO THE NORTHERN GULF OF MEXICO...WHILE
TRAILING TO VERACRUZ. AS IT SURGES INTO THE GULF A 35-40KT LOW
LEVEL JET MAXIMA IS TO DEVELOP ACROSS THE WESTERN GULF INTO THE
SOUTHERN STATES OF MEXICO. STRONG BOUNDARY LAYER WINDS ARE TO THEN
PERSIST THROUGH FRIDAY MORNING. AS IT ENTERS COAHUILA-TAMAULIPAS
EARLY ON THURSDAY THIS IS TO FAVOR LIGHT RAINFALL AMOUNTS...WITH
ACCUMULATION OF 00-05MM/DAY AND MAXIMA OF 10MM. THIS INCREASES TO
05-10MM/DAY AND MAXIMA OF 15MM OVER NORTHERN VERACRUZ EARLY ON
THURSDAY. THE MOST SIGNIFICANT AMOUNTS... HOWEVER...ARE EXPECTED
TO THE SOUTH ACROSS VERACRUZ-CHIAPAS...WHERE IT IS TO FAVOR
RAINFALL AMOUNTS OF 15-20MM/DAY AND MAXIMA OF 35-70MM DURING THE
DAY THURSDAY TO FRIDAY. MAXIMA THEN DECREASES TO 25-50MM ON
FRIDAY-SATURDAY.

AMPLIFYING POLAR TROUGH OVER NORTH AMERICA IS TO PRESS AGAINST A
RIDGE TO THE SOUTH AND EAST. THE 250 HPA RIDGE EXTENDS NORTH
ACROSS CENTRAL AMERICA/SOUTHERN MEXICO-GULF TO THE CENTRAL USA.
THIS RIDGE IS TO INITIALLY HOLD UNCHANGED...THEN QUICKLY FLATTEN
THROUGH THURSDAY MORNING AS THE AFOREMENTIONED POLAR TROUGH
AMPLIFIES ACROSS NORTH AMERICA. SIMILAR EVOLUTION IS EXPECTED AT
500 HPA...WITH CLOSED HIGH OVER THE YUCATAN CHANNEL FORECAST TO
ANCHOR A RIDGE ACROSS THE GULF-THE GREATER ANTILLES-CENTRAL
AMERICA INTO THE CARIBBEAN BASIN. THROUGH WEDNESDAY EVENING THE
HIGH RELOCATES TO THE BAHAMAS...WHILE THE RIDGE BUILDS ACROSS THE
WESTERN TO THE CENTRAL ATLANTIC. IT THEN SETTLES JUST SOUTH OF
BERMUDA LATER ON THURSDAY. THE PERSISTENT MID LEVEL RIDGE PATTERN
IS TO HELP SUSTAIN A STRONG CAP INVERSION ACROSS THE GREATER
ANTILLES-CENTRAL AMERICA-SOUTHERN STATES OF MEXICO.

AT LOW LEVELS...EXPECTING A HIGH TO ROLL TO THE WESTERN ATLANTIC
LATER TODAY/EARLY WEDNESDAY MORNING...SETTLING TO THE
SOUTH-SOUTHEAST OF BERMUDA LATER ON WEDNESDAY/THURSDAY MORNING. AS
THE HIGH/RIDGE MIGRATES...PRESSURE GRADIENT OVER THE
WESTERN-CENTRAL CARIBBEAN IS TO GRADUALLY SLACKEN...WHILE OVER THE
EASTERN CARIBBEAN/TROPICAL ATLANTIC IT IS TO TIGHTEN. WINDS OVER
CENTRAL AMERICA-EASTERN TROPICAL PACIFIC ARE TO PEAK AT 25-30KT
DURING THE NEXT FEW DAYS. OVER THE EASTERN CARIBBEAN...WINDS OF
15-20KT ARE EXPECTED THROUGH WEDNESDAY MORNING...INCREASING TO
30-35KT LATER IN THE DAY/EARLY THURSDAY MORNING AS THE GRADIENT
TIGHTENS TO THE NORTH. THE SURGING TRADES ARE TO GRADUALLY WEAKEN
LATER ON FRIDAY/EARLY SATURDAY MORNING. THE STRONG EAST-NORTHEAST
TRADE WINDS ARE TO ADVECT CLUSTERS OF SHALLOW MOISTURE ACROSS THE
ISLANDS INTO THE CARIBBEAN FROM TIME-TO-TIME...WHILE ALSO FAVORING
THE GENERATION OF STREAMERS ACROSS THE LESSER ANTILLES. ACROSS THE
NORTHERN LEEWARD-VIRGIN ISLES-PUERTO RICO AND NORTHERN HISPANIOLA
THIS IS TO FAVOR RAINFALL AMOUNTS OF 00-05MM/DAY AND MAXIMA OF
10MM. ACROSS THE SOUTHERN LEEWARD-FRENCH ISLES HIGHER AMOUNTS ARE
EXPECTED THROUGH THURSDAY MORNING...WITH ACCUMULATION OF
05-10MM/DAY AND ISOLATED MAXIMA OF 15MM. THIS THEN DECREASES TO
00-05MM/DAY.

EAST OF THE UPPER LEVEL RIDGE...A TUTT EXTENDS TO THE SOUTHWEST
ALONG 30N 50W-EASTERN CARIBBEAN TO NORTHERN SOUTH AMERICA. UNDER
INFLUENCE OF THE RIDGE TO THE WEST THE TROUGH IS TO STRETCH
FARTHER WEST ACROSS NORTHERN SOUTH AMERICA TO SOUTHERN CENTRAL
AMERICA...WITH A CLOSED LOW TO FORM OVER THE SOUTHERN CARIBBEAN
LATER ON FRIDAY. A SUBTROPICAL JET MAXIMA IS TO BOUND THE SOUTHERN
FRINGES OF THIS TROUGH...TO ALIGN ACROSS NORTHERN
COLOMBIA-VENEZUELA AND OVER THE ISLAND CHAIN. THE DEEP TROUGH IS
TO INTERACT WITH THE ITCZ OVER THE GUIANAS...TO SUSTAIN ORGANIZED
CONVECTION ACROSS FRENCH GUIANA-NORTHEAST SURINAME THROUGH
WEDNESDAY MORNING...WHERE IT IS TO FAVOR RAINFALL AMOUNTS OF
10-15MM/DAY AND MAXIMA OF 20-40MM. THROUGH WEDNESDAY THIS
DECREASES TO 05-10MM/DAY AND MAXIMA OF 15MM...SURGING ONCE AGAIN
LATER ON THURSDAY WHEN MAXIMA PEAKS AT 20-40MM. ACROSS NORTHWEST
SURINAME TO GUYANA THIS IS TO THEN FAVOR RAINFALL AMOUNTS OF
05-10MM/DAY AND MAXIMA OF 15-20MM THROUGH WEDNESDAY...INCREASING
TO 10-15MM/DAY AND MAXIMA OF 20-35MM EARLY ON THURSDAY. OTHER
ENHANCEMENT TO THE WEST IS EXPECTED ACROSS NORTHWEST
VENEZUELA-SANTANDERES COLOMBIA ON DAYS 02-04...WHERE DIGGING TUTT
AND FAVORABLE JET DYNAMICS ARE TO INTERACT WITH TERRAIN/LAKE
MARACAIBO TO FAVOR RAINFALL AMOUNTS OF 05-10MM/DAY AND MAXIMA OF
15-20MM. FURTHERMORE...THE TROUGH ALOFT...AS IT RETROGRESSES
ACROSS NORTHERN SOUTH AMERICA...IS TO THEN ENHANCE CONVECTIVE
DEVELOPMENT ACROSS THE ANDEAN REGION/WESTERN PLAINS OF COLOMBIA.
INITIALLY EXPECT RAINFALL AMOUNTS OF 00-05MM/DAY AND MAXIMA OF
10MM. BUT AS THE TROUGH ALOFT ENTERS NORTHERN SOUTH AMERICA THIS
INCREASES TO 05-10MM/DAY AND MAXIMA OF 15-20MM EARLY ON THURSDAY
THROUGH FRIDAY.

THE DEEPENING MID/UPPER TROUGH IS TO THEN FAVOR MOISTURE ADVECTION
ACROSS THE SOUTHERN WINDWARD ISLANDS LATER ON TUESDAY...WITH THE
MOIST PLUME TO CONTINUE ALONG THE COAST TO THE ABC ISLANDS THROUGH
WEDNESDAY. ACROSS TRINIDAD/TOBAGO THIS IS TO FAVOR RAINFALL
AMOUNTS OF 05-10MM/DAY AND MAXIMA OF 15-20MM ON
TUESDAY-WEDNESDAY...WHILE ACROSS THE ABC ISLANDS EXPECTING
RAINFALL AMOUNTS OF 00-05MM/DAY AND MAXIMA OF 10MM LATER ON
TUESDAY/EARLY WEDNESDAY MORNING. THIS INCREASES TO 05-10MM/DAY AND
MAXIMA OF 15MM ON WEDNESDAY.

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)
$$





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