Prognostic Meteorological Discussion
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FXCA20 KWBC 021930
PMDCA

TROPICAL DISCUSSION - INTERNATIONAL DESKS
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
229 PM EST MON MAR 02 2015

DISCUSSION FROM MARCH 02/00UTC: A MID/UPPER LEVEL CLOSED LOW IS TO
FORM OFF THE SOUTH COAST OF CALIFORNIA LATER THIS EVENING...WHERE
IT IS TO MEANDER THROUGH TUESDAY AFTERNOON. MEANWHILE...THIS IS TO
FAVOR A MOIST ADVECTIVE PATTERN ACROSS BAJA PENINSULA-NORTHWEST
STATES OF MEXICO...WHERE WE EXPECT RAINFALL AMOUNTS OF 10-15MM/DAY
AND MAXIMA OF 20-45MM/DAY. THROUGH WEDNESDAY THIS DECREASES TO
00-05MM/DAY AND MAXIMA OF 10MM...WITH MOST ACTIVE OVER
SONORA/WESTERN CHIHUAHUA.

AMPLIFYING POLAR TROUGH IS TO THEN MOVE ACROSS THE MIDWESTERN USA
EARLY ON WEDNESDAY...WITH THE CLOSED LOW TO THE SOUTH TO RAPIDLY
WEAKEN AS SHORT WAVE ENERGY SHEARS EASTWARD ACROSS MEXICO. THE
DEEPENING MID LEVEL TROUGH IS TO SUSTAIN A PROGRESSIVE FRONT
ACROSS NORTH AMERICA...WITH AXIS ACROSS TEXAS TO THE RIO BRAVO
LATER ON WEDNESDAY. EARLY ON THURSDAY MORNING THE FRONT MOVES TO
THE NORTHWEST GULF/NORTHEAST STATES OF MEXICO. A 35-40KT NORTHERLY
WIND SURGE IS TO THEN DRIVE THIS FRONT SOUTH ACROSS THE GULF OF
MEXICO...WITH AXIS TO EXTEND ACROSS CENTRAL FLORIDA TO VERACRUZ
LATER ON THURSDAY. AS IT ENTERS COAHUILA-TAMAULIPAS THIS IS TO
ONLY FAVOR LIGHT RAINFALL AMOUNTS... WITH ACCUMULATION OF
00-05MM/DAY AND MAXIMA OF 10MM. MOST SIGNIFICANT AMOUNTS ARE
EXPECTED TO THE SOUTH ACROSS VERACRUZ-CHIAPAS...WHERE IT IS TO
FAVOR RAINFALL AMOUNTS OF 15-20MM/DAY AND MAXIMA OF 25-50MM DURING
THE DAY THURSDAY.

POLAR PERTURBATIONS OVER NORTH AMERICA CONTINUE TO PRESS AGAINST
PERSISTENT RIDGE TO THE SOUTH AND EAST. AT 250 HPA THE RIDGE
EXTENDS NORTH ACROSS CENTRAL AMERICA/SOUTHERN MEXICO-GULF TO THE
CENTRAL USA. THIS RIDGE IS TO HOLD OVER THE NEXT TWO DAYS...THEN
STARTS TO FLATTEN AS AFOREMENTIONED POLAR TROUGH AMPLIFIES ACROSS
NORTH AMERICA. SIMILAR EVOLUTION IS EXPECTED AT 500 HPA...WITH
HIGH OVER THE YUCATAN TO EXTEND A RIDGE NORTH ACROSS THE GULF TO
THE SOUTHEAST USA AND EAST ACROSS THE GREATER ANTILLES. THROUGH
WEDNESDAY EVENING THE HIGH RELOCATES TO THE BAHAMAS...WHILE THE
RIDGE BUILDS ACROSS THE WESTERN TO THE CENTRAL ATLANTIC.
PERSISTENT MID LEVEL RIDGE PATTERN IS TO HELP SUSTAIN A STRONG CAP
INVERSION ACROSS THE GREATER ANTILLES-CENTRAL AMERICA-SOUTHERN
STATES OF MEXICO.

AS THE RIDGE PATTERN ALOFT EVOLVES...IT IS TO ALSO AFFECT THE LOW
LEVEL FLOW PATTERN. EARLY IN THE CYCLE A POLAR TROUGH OVER THE
WESTERN ATLANTIC SPLITS THE RIDGE IN TWO DISTINCT CELLS...ONE OVER
THE GULF/FAR WESTERN ATLANTIC AND ANOTHER OVER THE EASTERN
ATLANTIC. AS THE POLAR TROUGH MOVES EAST THE RIDGE IS TO ROLL
BEHIND...SETTLING OVER THE CENTRAL/WESTERN ATLANTIC WHILE
ANCHORING ON A CLOSED HIGH OVER BERMUDA. AS THE HIGH/RIDGE
MIGRATES... GRADIENT OVER THE WESTERN-CENTRAL CARIBBEAN IS TO
GRADUALLY SLACKEN...WHILE OVER THE EASTERN CARIBBEAN/TROPICAL
ATLANTIC IT IS TO TIGHTEN. AS A RESULT...STRONG LOW LEVEL WINDS OF
35-45KT ARE TO PERSIST ACROSS CENTRAL AMERICA THROUGH TUESDAY
MORNING...WITH WINDS OF 25-30KT EXPECTED THEREAFTER. OVER THE
EASTERN CARIBBEAN...WINDS OF 15-20KT ARE EXPECTED THROUGH
WEDNESDAY MORNING...INCREASING TO 30-35KT LATER IN THE DAY AS THE
GRADIENT TIGHTENS TO THE NORTH. EAST-NORTHEASTERLY WINDS ARE TO
THEN PREVAIL ACROSS THE ISLANDS-CARIBBEAN BASIN...WITH CLUSTERS OF
SHALLOW MOISTURE TO ADVECT ACROSS THE ISLANDS INTO THE CARIBBEAN
FROM TIME-TO-TIME. 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 TUESDAY...WITH
ACCUMULATION OF 05-10MM/DAY AND ISOLATED MAXIMA OF 15-20MM.

A TUTT BOUNDS THE EASTERN FRINGES OF THE UPPER LEVEL RIDGE...WITH
AXIS SOUTHWEST ACROSS THE NORTHEAST CARIBBEAN ISLES TO NORTHERN
SOUTH AMERICA. THROUGH TUESDAY EVENING THE POLAR TROUGH EXITING
THE EASTERN USA IS TO PHASE WITH THE TUTT...STRENGTHENING THE
MID/UPPER TROUGH PATTERN. THE DEEP TROUGH PATTERN IS TO ENHANCE
ITCZ CONVERGENCE ACROSS FRENCH GUIANA-NORTHEAST SURINAME EARLY IN
THE CYCLE...TO FAVOR RAINFALL AMOUNTS OF 15-20MM/DAY AND MAXIMA OF
25-50MM. THROUGH WEDNESDAY THIS DECREASES TO 05-10MM/DAY AND
MAXIMA OF 15MM. ACROSS NORTHWEST SURINAME TO GUYANA INITIALLY
EXPECT RAINFALL AMOUNTS OF 00-05MM/DAY AND MAXIMA OF 10MM. BUT AS
THE TROUGH REACHES MAXIMUM AMPLITUDE ON DAY 02 THIS IS TO
GRADUALLY INCREASES TO 10-15MM/DAY AND MAXIMA OF 20-35MM THROUGH
MIDDAY ON WEDNESDAY. ALSO... CONVECTIVE ENHANCEMENT IS LIKELY
ACROSS NORTHWEST VENEZUELA-SANTANDERES COLOMBIA ON DAYS
03-04...WITH RAINFALL AMOUNTS OF 05-10MM/DAY AND MAXIMA OF 15-25MM.

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 15-25MM LATER ON WEDNESDAY.

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)
$$




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