Prognostic Meteorological Discussion
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FXCA20 KWBC 021813
PMDCA

TROPICAL DISCUSSION - INTERNATIONAL DESKS
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
212 PM EDT WED SEP 02 2015

DISCUSSION FROM SEP 02/12 UTC: WEST OVER THE DOMAIN A MID/UPPER
LEVEL RIDGE REMAINS OVER WESTERN MEXICO-SOUTHWEST USA. A 250 HPA
CLOSED HIGH OVER NORTHWEST MEXICO IS TO ANCHOR THIS AXIS OVER THE
NEXT COUPLE DAYS. A TROUGH TO THE WEST...OVER THE
PACIFIC...PRESSES AGAINST THIS RIDGE. THIS...IN-TURN...FAVORS A
LONG FETCH SOUTHWESTERLY FLOW ACROSS BAJA PENINSULA-SONORA MEXICO
TO THE SOUTHWEST USA...WITH SHORT WAVE VORTICES EMBEDDING IN THIS
FLOW. AS THEY STREAM ACROSS NORTHWEST MEXICO THIS WILL COMBINE
WITH DIURNAL HEATING TO FAVOR DEEP LAYER CONVECTIVE INSTABILITY.
ACROSS SOUTHERN BAJA PENINSULA THIS IS TO FAVOR SCATTERED
CONVECTION WITH RAINFALL AMOUNTS OF 05-10MM/DAY AND MAXIMA OF
15-20MM...WITH MOST INTENSE ON FRIDAY. OVER SONORA
MEXICO...MEANWHILE...EXPECTING RAINFALL AMOUNTS 05-10MM/DAY AND
MAXIMA OF 15-20MM. ON THURSDAY THIS INCREASES TO 10-15MM/DAY AND
MAXIMA OF 20-35MM.

DOWNSTREAM FROM THE CONTINENTAL RIDGE...A TROUGH MEANDERS ACROSS
THE WESTERN GULF OF MEXICO TO THE EASTERN STATES OF MEXICO. UNDER
INFLUENCE OF THE RIDGE TO THE WEST THE TROUGH IS TO MEANDER TO THE
SOUTH-SOUTHWEST OVER THE NEXT FEW DAYS...WITH SHORT WAVE ENERGY
SHEARING ACROSS THE CENTRAL TO SOUTHWEST STATES OF MEXICO. EARLY
IN THE CYCLE THE TROUGH WILL ENHANCE CONVECTION ACROSS NORTHEAST
MEXICO TO FAVOR RAINFALL AMOUNTS OF 05-10MM/DAY AND MAXIMA OF
15-20MM. OVER CENTRAL-SOUTHWEST MEXICO THIS WILL COMBINE WITH
DIURNAL HEATING TO FAVOR LATE AFTERNOON CONVECTION...WITH RAINFALL
AMOUNTS OF 15-20MM/DAY AND MAXIMA OF 30-60MM. ACROSS THE SOUTHERN
STATES OF MEXICO/THE YUCATAN EXPECT DIURNAL CONVECTION TO FAVOR
RAINFALL AMOUNTS OF 10-15MM/DAY AND MAXIMA OF 20-40MM.

BROAD CELL OF THE SUBTROPICAL RIDGE IS INITIALIZED TO THE
EAST...EXTENDING FROM THE CENTRAL/EASTERN GULF OF MEXICO TO THE
BAHAMAS/NORTHERN CARIBBEAN ISLANDS. A 250 HPA HIGH OVER FLORIDA IS
TO ANCHOR THIS AXIS OVER THE NEXT COUPLE OF DAYS. LATER ON FRIDAY
THE RIDGE IS TO WEAKEN UNDER PRESSURE FROM AN AMPLIFYING TROUGH
OVER THE EASTERN USA/WESTERN ATLANTIC. UNDER INFLUENCE OF THE
MID/UPPER LEVEL RIDGE EXPECT A FAIRLY STRONG CAP INVERSION TO
DEVELOP ACROSS PUERTO RICO-VIRGIN ISLES-HISPANIOLA AND THE
BAHAMAS. THIS IS TO PERSIST THROUGH FRIDAY MORNING...THEN LIFT
ABOVE 750/700 HPA DURING THE DAY ON FRIDAY. AT 850 HPA THIS
REFLECTS AS A NARROW RIDGE NORTH OF THE ISLANDS. ACROSS THE
NORTHERN CARIBBEAN ISLES THIS IS TO GENERALLY FAVOR LIGHT EASTERLY
TRADES...WHILE OVER THE SOUTHERN CARIBBEAN INTO CENTRAL AMERICA
THE WINDS ARE TO PEAK AT 10-15KT.

A TUTT ALONG THE SOUTHERN FRINGES OF THE SUBTROPICAL RIDGE EXTENDS
OVER THE NORTHERN CARIBBEAN WHILE ANCHORING ON TWO CLOSED
LOWS...WITH ONE OVER THE CAYMAN ISLES WHILE THE OTHER CENTERS NEAR
THE VIRGIN/NORTHERN LEEWARD ISLES. UNDER INFLUENCE OF THE RIDGE TO
THE NORTH...THE WESTERN CARIBBEAN TUTT LOW IS TO DRIFT WEST TO THE
YUCATAN EARLY ON FRIDAY...WITH AXIS TO THEN GRADUALLY WEAKEN.
MEANWHILE...THE MEANDERING UPPER LEVEL TROUGH IS TO ENHANCE
CONVECTION ACROSS CENTRAL AMERICA AND THE NORTHWEST CARIBBEAN.
ACROSS THE CAYMAN ISLES THIS IS TO FAVOR RAINFALL AMOUNTS OF
00-05MM/DAY AND MAXIMA OF 10MM. OVER CUBA MOST INTENSE IS EXPECTED
ON WESTERN PORTIONS OF THE ISLAND WITH RAINFALL AMOUNTS OF
05-10MM/DAY AND MAXIMA OF 15-20MM. ACROSS NORTHERN CENTRAL AMERICA
THIS IS TO FAVOR RAINFALL AMOUNTS OF 10-15MM/DAY AND MAXIMA OF
20-30MM...WHILE OVER SOUTHERN CENTRAL AMERICA IN POSITIVE
INTERACTION WITH THE ITCZ EXPECT RAINFALL AMOUNTS OF 15-20MM/DAY
AND MAXIMA OF 25-50MM. THE EASTERN CARIBBEAN TUTT
LOW...MEANWHILE...IS TO EXTEND A SHORT WAVE TROUGH TO THE ABC
ISLANDS/NORTHERN VENEZUELA. BEST CONVECTIVE ENHANCEMENT WITH THIS
FEATURE IS EXPECTED TO THE SOUTH OVER VENEZUELA...WHERE IN
INTERACTION WITH THE NEAR EQUATORIAL TROUGH EXPECT RAINFALL
AMOUNTS OF 05-10MM/DAY AND MAXIMA OF 15-25MM. OVER THE
LEEWARD-VIRGIN ISLES EXPECTING LIGHT CONVECTION ON THURSDAY TO
SUSTAIN RAINFALL AMOUNTS OF 00-05MM/DAY AND MAXIMA OF 10MM.

TROPICAL/EASTERLY WAVES INITIALIZED AT 12UTC
INITIAL  24     36     48     60     72     84     96        TYPE
41W     43W    46W    48W    51W    54W    57W    59W        TW
71W     74W    77W    79W    81W    83W    86W    89W        TW
81W     83W    86W    88W    90W    92W    94W    96W        TW
95W     97W    99W   101W   102W   103W   104W   105W        TW

TROPICAL WAVE IS INITIALIZED ALONG 41W. THIS REACHES NORTHERN
FRENCH GUIANA EARLY ON FRIDAY MORNING...WHERE IT IS TO FAVOR
COASTAL CONVECTION WITH RAINFALL AMOUNTS OF 05-10MM/DAY AND MAXIMA
OF 15MM. OVER NORTHERN SURINAME-GUYANA THIS IS TO ALSO FAVOR
RAINFALL AMOUNTS OF 05-10MM/DAY AND MAXIMA OF 15MM DURING THE DAY
ON FRIDAY TO SATURDAY MORNING.

TROPICAL WAVE ALONG 71W IS TO ENTER AN AREA OF UPPER CONVERGENCE
AS IT MOVES ACROSS HISPANIOLA TO JAMAICA...THUS HAVING MINIMAL
IMPACT ACROSS THE NORTHERN CARIBBEAN ISLANDS. MOST ACTIVE
CONVECTION IS EXPECTED TO THE SOUTH ALONG THE NEAR EQUATORIAL
TROUGH OVER NORTHWEST VENEZUELA-COLOMBIA. IN THIS AREA IT IS TO
TRIGGER SCATTERED CONVECTION WITH RAINFALL AMOUNTS OF 15-20MM/DAY
AND MAXIMA OF 25-50MM ON WEDNESDAY TO THURSDAY MORNING. AS IT
MOVES ACROSS PANAMA TO COSTA RICA THIS IS TO THEN INTERACT WITH
THE ITCZ IN SUPPORT OF RAINFALL AMOUNTS OF 15-20MM/DAY AND MAXIMA
OF 30-60MM. OVER EASTERN NICARAGUA IT IS TO THEN TRIGGER RAINFALL
ACCUMULATION OF 10-15MM/DAY AND MAXIMA OF 20-45MM.

TROPICAL WAVE ALONG 81W CONTINUES TO INTERACT WITH THE WESTERN
CARIBBEAN TUTT LOW. OVER WESTERN PANAMA-COSTA RICA TO SOUTHERN
NICARAGUA EXPECT RAINFALL AMOUNTS OF 15-20MM/DAY AND MAXIMA OF
25-50MM...WHILE OVER EASTERN NICARAGUA/NORTHEAST HONDURAS EXPECT
RAINFALL ACCUMULATION OF 10-15MM/DAY AND MAXIMA OF 20-35MM. OVER
EL SALVADOR-SOUTHERN HONDURAS-SOUTHERN GUATEMALA THIS IS TO
TRIGGER RAINFALL AMOUNTS OF 15-20MM/DAY AND MAXIMA OF 30-60MM
EARLY ON THURSDAY MORNING. ACROSS NORTHERN HONDURAS TO
BELIZE/NORTHERN GUATEMALA EXPECTING RAINFALL AMOUNTS OF
10-15MM/DAY AND MAXIMA OF 20-30MM. OVER THE SOUTHERN STATES OF
MEXICO THE WAVE IS TO THEN TRIGGER RAINFALL AMOUNTS OF 15-20MM/DAY
AND MAXIMA OF 25-50MM.

TROPICAL WAVE ALONG 95W IS TO INTERACT WITH MEANDERING MID/UPPER
LEVEL TROUGH OVER THE WESTERN GULF-CENTRAL MEXICO. AS THE WAVE
MOVES ACROSS CENTRAL-SOUTHWEST MEXICO IT IS TO FAVOR SCATTERED
DEEP CONVECTION WITH RAINFALL AMOUNTS OF 15-20MM/DAY AND MAXIMA OF
30-60MM.

SALMON...MS (ANTIGUA AND BARBUDA)
CABRERA...ONAMET (THE DOMINICAN REPUBLIC)
DAVISON...WPC (USA)
GALVEZ...WPC (USA)

$$




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