Prognostic Meteorological Discussion
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FXCA20 KWBC 021915
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TROPICAL DISCUSSION - INTERNATIONAL DESKS
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
215 PM EST FRI DEC 02 2016

TROPICAL DISCUSSION FROM DEC 02/12 UTC: DEEPENING MID/UPPER LEVEL
TROUGH DOMINATES THE FLOW ACROSS THE WESTERN PORTIONS OF THE
DOMAIN. THE TROUGH IS TO AMPLIFY ACROSS THE WESTERN USA-NORTHWEST
MEXICO/BAJA PENINSULA TO THE EASTERN PACIFIC...REACHING MAXIMUM
AMPLITUDE EARLY ON SATURDAY MORNING. ALONG THIS AXIS...A MID LEVEL
LOW IS EXPECTED TO CLOSED OVER NORTHWEST MEXICO LATER IN THE DAY.
THE DEEPENING TROUGH...AS IT EXTENDS TO THE EASTERN PACIFIC...IT
IS TO SUSTAIN A MOIST ADVECTIVE PATTERN ACROSS THE SOUTHWEST AND
NORTHWEST STATES OF MEXICO. LATER ON FRIDAY THE MOST ACTIVE
CONVECTION IS TO CLUSTER ACROSS SINALOA...WITH RAINFALL AMOUNTS OF
10-15MM/DAY AND MAXIMA OF 20-40MM...WHILE OVER COLIMA AND NAYARIT
EXPECTING RAINFALL AMOUNTS OF 05-10MM/DAY AND MAXIMA OF 15-20MM.
ON SATURDAY THE CONVECTION ALONG THE SIERRA MADRE IS FORECAST TO
INTENSIFY WHILE BUILDING NORTH...TO SUSTAIN RAINFALL AMOUNTS OF
15-20MM/DAY AND MAXIMA OF 25-50MM. ON SUNDAY THIS DECREASES TO
05-10MM/DAY AND MAXIMA OF 15-25MM. THE MID LEVEL VORTEX IS TO THEN
INTERACT WITH TRAILING END OF A FRONT OVER TEXAS/RIO
BRAVO...FAVORING CYCLOGENESIS LATER DURING THE WEEKEND. THIS IS TO
ALSO TRIGGER MODERATE CONVECTION ALONG THE RIO BRAVO BASIN. OVER
COAHUILA-TAMAULIPAS THIS IS TO THEN FAVOR SCATTERED CONVECTION. ON
SATURDAY TO SUNDAY THIS WILL RESULT IN RAINFALL AMOUNTS OF
10-15MM/DAY AND MAXIMA OF 20-35MM.

MID/UPPER LEVEL RIDGE OVER THE NORTHERN CARIBBEAN CONTINUES TO
WEAKEN UNDER PRESSURE FROM POLAR TROUGH STREAMING ACROSS THE
WESTERN NORTH ATLANTIC. MID LEVEL RIDGE IS TO THEN ALIGN
EAST-TO-WEST ACROSS THE NORTHERN CARIBBEAN ISLES TO THE SOUTHERN
STATES OF MEXICO/YUCATAN PENINSULA LATER TODAY. THIS PATTERN HOLDS
THROUGH SATURDAY MORNING WHEN THE RIDGE WILL THEN START TO AMPLIFY
AS THE AFOREMENTIONED TROUGH DEEPENS TO THE WEST OVER MEXICO.
THROUGH SATURDAY EVENING THE RIDGE IS FORECAST TO RAPIDLY BUILD
WHILE ANCHORING ON A 500 HPA HIGH OVER CUBA. THE BUILDING RIDGE IS
TO THEN STRENGTHEN THE TRADE WINDS CAP ACROSS THE NORTHERN
CARIBBEAN ISLES LATER DURING THE WEEKEND...AND THE LEEWARD ISLES
EARLY NEXT WEEK. AT LOW LEVELS... THE TROUGH TO THE NORTH SUSTAINS
A SURFACE FRONT THAT MOVES TO THE NORTHWEST BAHAMAS-SOUTH FLORIDA
LATER TODAY...WHILE TRAILING END MEANDERS ACROSS THE GULF OF
MEXICO TO TEXAS. THROUGH SUNDAY EVENING THE FRONT IS TO MEANDER
SOUTH ACROSS THE BAHAMAS WHILE TRAILING ACROSS FLORIDA-THE GULF TO
THE SOUTHERN USA. A BUILDING POLAR RIDGE TO THE NORTH AND WEST OF
THE FRONT IS TO GRADUALLY BECOME THE DOMINANT LOW LEVEL FEATURE
ACROSS THE SOUTHEAST USA-BAHAMAS-CUBA-HISPANIOLA AND THE NORTHERN
CARIBBEAN ON SATURDAY-SUNDAY. THIS IS TO TIGHTEN THE
GRADIENT...WITH LOW LEVEL EASTERLY TRADES ACROSS THE BASIN
FORECAST TO INCREASE TO 15-20KT. INITIALLY THE MOST INTENSE ARE
EXPECTED ACROSS THE CENTRAL/WESTERN CARIBBEAN...BUT LATER IN THE
WEEKEND/EARLY NEXT WEEK THEY ARE TO ENVELOP THE ENTIRE BASIN.
FURTHERMORE...THE BUILDING LOW LEVEL RIDGE WILL SUSTAIN A
PREFRONTAL SHEAR LINE THAT MOVES ACROSS THE NORTHWEST
BAHAMAS-WESTERN CUBA TO THE NORTHERN YUCATAN LATER ON
FRIDAY...WHERE IT IS TO FAVOR RAINFALL AMOUNTS OF 00-05MM/DAY AND
MAXIMA OF 10MM. ON SATURDAY IT MOVES ACROSS THE SOUTHEAST
BAHAMAS/TURKS-JAMAICA WHILE TRAILING TO THE NORTHWEST
CARIBBEAN/NORTHERN HONDURAS...TO SUSTAIN RAINFALL AMOUNTS OF
05-10MM/DAY AND MAXIMA OF 15-25MM. IT IS TO THEN SLOWLY PULL
ACROSS HISPANIOLA LATER ON SATURDAY/EARLY SUNDAY
MORNING...TRIGGERING RAINFALL AMOUNTS OF 05-10MM/DAY AND MAXIMA OF
15MM. AS IT MOVES EAST ACROSS THE NORTHERN CARIBBEAN ISLES THIS IS
TO ALSO FAVOR A PREFRONTAL TROUGH THAT IS TO EXTEND NORTH ACROSS
THE VIRGIN ISLES/PUERTO RICO ON SATURDAY. THIS WILL ENHANCE LOW
LEVEL MOISTURE CONVERGENCE TO FAVOR RAINFALL ACCUMULATION OF
05-10MM/DAY AND MAXIMA OF 15MM. BUILDING RIDGE IS TO THEN DISPLACE
THE TROUGH TO THE EAST WHILE WINDS BACK TO THE NORTHEAST. THIS IS
TO THEN TRIGGER EARLY MORNING CONVECTION ACROSS HISPANIOLA-PUERTO
RICO-VIRGIN ISLES-NORTHERN LEEWARD ISLES...WITH RAINFALL AMOUNTS
OF 00-05MM/DAY AND ISOLATED MAXIMA OF 10MM. THE SHEAR LINE IS TO
THEN CONTINUE SOUTH ACROSS THE LEEWARD ISLES LATER ON SUNDAY INTO
THE WINDWARD ISLES LATER IN THE DAY...TO FAVOR RAINFALL AMOUNTS OF
05-10MM/DAY AND MAXIMA OF 15MM.

RIDGE NORTH OF THE ISLANDS IS STEERING A SHORT WAVE TROUGH WEST
ACROSS NORTHWEST VENEZUELA TO NORTHERN COLOMBIA/SOUTHERN
CARIBBEAN. AS THE RIDGE TO THE NORTH STRENGTHENS...THE SHORT WAVE
TROUGH IS TO SHEAR TO THE SOUTHWEST ACROSS PANAMA/COSTA RICA TO
THE EASTERN TROPICAL PACIFIC...AND LATER ON SUNDAY IT IS FORECAST
TO DISSIPATE. MEANWHILE...THIS IS TO ENHANCE CONVECTION ACROSS
COLOMBIA/WESTERN VENEZUELA. IN THIS AREA EXPECTING RAINFALL
AMOUNTS OF 15-20MM/DAY AND MAXIMA OF 25-50MM. AS THE TROUGH
WEAKENS THIS DECREASES TO 10-15MM/DAY AND MAXIMA OF 20-35MM LATER
ON SUNDAY.

TROPICAL/EASTERLY WAVES INITIALIZED AT 12UTC:
INITIAL    24      36      48      60      72      84      96
TYPE
48W       50W     52W     54W     56W     58W     60W  DISSIPATES
TW
72W       75W     78W     81W     83W     86W     DISSIPATES
INDCD TROF

WANING TROPICAL WAVE EXTENDS NORTH ALONG 48W TO 14N. IT IS TO
ENTER FRENCH GUIANA LATER TODAY...TO CONTINUE INTO SURINAME DURING
THE DAY ON SATURDAY. THIS IS TO TRIGGER RAINFALL AMOUNTS OF
00-05MM/DAY AND MAXIMA OF 10MM. IT IS TO SLOWLY MOVE WEST ACROSS
GUYANA TO EASTERN VENEZUELA ON SUNDAY...BUT AS AFOREMENTIONED
SHEAR LINE ENTERS THE WINDWARD ISLES THE WAVE IS FORECAST TO
DISSIPATE. MEANWHILE...IT IS TO FAVOR RAINFALL AMOUNTS OF
05-10MM/DAY AND MAXIMA OF 15MM.

A PERTURBATION IN THE EASTERLY TRADES LIES ALONG 72W TO SOUTHERN
HISPANIOLA. THIS FAVORS A MOIST SOUTHEASTERLY FLOW ACROSS THE
EASTERN CARIBBEAN THAT IS ADVECTING MOISTURE ACROSS PUERTO
RICO-HISPANIOLA...WHERE IT IS TO FAVOR RAINFALL AMOUNTS OF
05-10MM/DAY AND MAXIMA OF 15MM. MOIST PLUME IS TO ADVECT ACROSS
THE NORTHERN CARIBBEAN TO JAMAICA ON SATURDAY...WHERE IT IS TO
COINCIDE WITH SHEAR LINE ENTERING THE NORTHERN CARIBBEAN. THIS IS
TO THEN SUSTAIN RAINFALL AMOUNTS OF 05-10MM/DAY AND MAXIMA OF
15-25MM. MOISTURE SPREADS ACROSS THE CAYMAN ISLES ON SUNDAY...TO
FAVOR RAINFALL AMOUNTS OF 00-05MM/DAY AND MAXIMA OF 10MM. MOST
ACTIVE CONVECTION WITH THIS FEATURE IS EXPECTED TO THE SOUTH AS IT
INTERACTS WITH THE NEAR EQUATORIAL TROUGH OVER WESTERN
VENEZUELA/COLOMBIA...TO TRIGGER MODERATE CONVECTION WITH
ACCUMULATION OF 15-20MM/DAY AND MAXIMA OF 25-50MM IN SCATTERED
CONVECTION. ACROSS PANAMA-COSTA RICA THIS IS TO THEN FAVOR
RAINFALL AMOUNTS OF 10-15MM/DAY AND MAXIMA OF 20-35MM...WHILE OVER
EASTERN NICARAGUA/NORTHEAST HONDURAS EXPECT RAINFALL AMOUNTS OF
05-10MM/DAY AND MAXIMA OF 15-20MM. THIS IS TO AFFECT WESTERN
NICARAGUA/SOUTHERN HONDURAS-EL SALVADOR ON SUNDAY TO FAVOR
RAINFALL AMOUNTS OF 05-10MM/DAY AND MAXIMA OF 15-25MM.

JIMENEZ...IMN (COSTA RICA)
MIRANDA...INAMEH (VENEZUELA)
DAVISON/GALVEZ...WPC (USA)

$$




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