Prognostic Meteorological Discussion
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FXCA20 KWBC 281916
PMDCA

TROPICAL DISCUSSION - INTERNATIONAL DESKS
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
316 PM EDT THU JUL 28 2016

TROPICAL DISCUSSION FROM JULY 28/12UTC: BUILDING CELL OF THE
SUBTROPICAL RIDGE EXTENDS OVER THE WESTERN ATLANTIC-FLORIDA
PENINSULA TO THE NORTHERN CARIBBEAN ISLES. THROUGH FRIDAY THE
RIDGE WILL EXPAND INTO THE GULF OF MEXICO. AS IT BUILDS WEST...THE
RIDGE WILL DISPLACE A TUTT ACROSS THE GULF INTO MEXICO. AS THE
TROUGH MOVES WEST...IT IS TO SHEAR SHORT WAVE VORTICES ACROSS THE
NORTHERN STATES OF MEXICO. THE INFLOW OF COOLER AIR ALOFT AND
CYCLONIC VORTICITY WILL ENHANCE DIURNAL CONVECTION. ACROSS
TAMAULIPAS-COAHUILA TO THE NORTHEAST THIS IS TO FAVOR RAINFALL
AMOUNTS OF 10-15MM/DAY AND MAXIMA OF 20-35MM THROUGH FRIDAY...THEN
GRADUALLY DECREASE TO 05-10MM/DAY AND MAXIMA OF 15MM ON SATURDAY.
FORECAST OF THE GDI SHOWS ENHANCED INSTABILITY TO THE WEST ALONG
THE SIERRA MADRE OCCIDENTAL...BETWEEN SONORA AND NAYARIT...PEAKING
AROUND 50 OVER THE NEXT TWO DAYS. IN THIS AREA EXPECTING RAINFALL
AMOUNTS OF 15-20MM/DAY AND MAXIMA OF 35-70MM IN ORGANIZED DEEP
CONVECTION. ON SATURDAY THE MAXIMA DECREASES TO 25-50MM. ON THE
SIERRA MADRE DEL SUR AND THE CENTRAL STATES EXPECTING RAINFALL
AMOUNTS OF 10-15MM/DAY AND MAXIMA OF 20-30MM...WITH MAXIMA OF
20-40MM ON SATURDAY. OVER THE YUCATAN AND SOUTHERN STATES OF
MEXICO THE RETROGRESSING TUTT WILL RESULT IN RAINFALL AMOUNTS OF
10-15MM/DAY AND MAXIMA OF 20-35MM THROUGH SATURDAY MORNING. THIS
THEN DECREASES TO 05-10MM/DAY AND MAXIMA OF 15-20MM ON SATURDAY TO
SUNDAY.

THE SUBTROPICAL RIDGE TO THE EAST IS TO CENTER AT 500 HPA ON A
CLOSED HIGH JUST NORTH OF THE BAHAMAS. AS THE RIDGE ENVELOPS THE
NORTHERN CARIBBEAN ISLES IT IS TO SUSTAIN A CAP INVERSION THAT IS
TO INHIBIT ORGANIZED DEEP CONVECTION. THE RIDGE...AS IT HOLDS...IS
TO STEER A TUTT ACROSS THE NORTHERN CARIBBEAN. THE TUTT ORIGINATES
ON A CLOSED LOW NORTH OF THE LEEWARD ISLES...WHILE ANOTHER EXTENDS
OVER THE EASTERN CARIBBEAN. THROUGH FRIDAY THESE MERGE INTO A
BROAD TROUGH OVER THE CENTRAL CARIBBEAN...WITH AXIS NORTH FROM
NORTHERN COLOMBIA TO THE DOMINICAN REPUBLIC. ON SATURDAY IT
MEANDERS WEST ACROSS JAMAICA-CUBA AND THE BAHAMAS WHILE TRAILING
TO THE SOUTHERN CARIBBEAN. UNDER PRESSURE FROM THIS FEATURE...THE
RIDGE NORTH OF THE ISLANDS IS TO THEN WEAKEN. AT MID LEVELS...THE
TUTT SUSTAINS AN INVERTED TROUGH ACROSS THE VIRGIN ISLES TO PUERTO
RICO LATER TODAY. THROUGH FRIDAY THIS MEANDERS WEST ALONG
75W/76W...CROSSING THE WINDWARD PASSAGE/TURKS AND CAICOS...NEARING
80W/82W ON SATURDAY. AS IT PULLS ACROSS THE LEEWARD-VIRGIN ISLES
THIS IS TO ONLY FAVOR LIGHT CONVECTION...WITH ACCUMULATION OF
00-05MM/DAY...WHILE OVER PUERTO RICO IT IS LIKELY TO SUSTAIN
ISOLATED MAXIMA OF 10MM IN WESTERN INTERIOR PORTIONS OF THE
ISLAND. ACROSS HISPANIOLA EXPECTING RAINFALL AMOUNTS OF
05-10MM/DAY AND MAXIMA OF 15MM. HIGHER AMOUNTS TO THE SOUTH ARE
EXPECTED AS IT INTERACTS WITH THE NEAR EQUATORIAL TROUGH. ACROSS
VENEZUELA EXPECTING RAINFALL AMOUNTS OF 10-15MM/DAY AND MAXIMA OF
20-35MM THROUGH FRIDAY...DECREASING TO 05-10MM/DAY AND MAXIMA OF
15-20MM ON FRIDAY TO SATURDAY. OVER COLOMBIA IT IS TO FAVOR
RAINFALL AMOUNTS OF 15-20MM/DAY AND MAXIMA OF 25-50MM THROUGH
FRIDAY...DECREASING TO 10-15MM/DAY AND MAXIMA OF 20-40MM
THEREAFTER. ACROSS JAMAICA EXPECTING RAINFALL AMOUNTS OF
05-10MM/DAY AND MAXIMA OF 15MM ON FRIDAY...WHILE OVER EASTERN
CUBA/THE SOUTHEAST BAHAMAS IT IS TO FAVOR RAINFALL AMOUNTS OF
00-05MM/DAY AND MAXIMA OF 10MM.

AT 250 HPA A SHORT WAVE RIDGE TO THE SOUTH EXTENDS OVER THE
SOUTHERN CARIBBEAN TO SOUTHERN CENTRAL AMERICA. THE RIDGE ALOFT IS
TO VENT ITCZ RELATED CONVECTION ACROSS SOUTHERN NICARAGUA-COSTA
RICA-PANAMA TO FAVOR RAINFALL AMOUNTS OF 10-15MM/DAY AND MAXIMA OF
20-40MM. AS THE AFOREMENTIONED TUTT RETROGRESSES ACROSS THE BASIN
IT IS TO PRESS AGAINST THIS AXIS...WITH MODELS SHOWING GRADUAL
EROSION THROUGH FRIDAY. TUTT IS TO THEN INTERACT WITH THE ITCZ TO
FAVOR RAINFALL AMOUNTS OF 15-20MM/DAY AND MAXIMA OF 25-50MM.

TROPICAL/EASTERLY WAVES INITIALED AT 12UTC.
INITIAL    24    36    48    60    72    84    96      TYPE
40W       45W   50W   55W   60W   64W   69W   74W      TW
49W       53W   57W   61W   65W   69W   73W   76W      TW
82W       84W   87W   91W   93W   96W   98W  100W      EW
92W       95W   97W   99W  101W  103W  105W  108W      EW

TROPICAL WAVE ALONG 40W SURGES ACROSS THE TROPICAL ATLANTIC...AND
THROUGH SATURDAY MORNING IT IS TO PULL ACROSS THE LEEWARD
ISLES...MOVING ACROSS PUERTO RICO LATER IN THE DAY. STRONG
BOUNDARY LAYER WINDS AND ORGANIZED CONVECTION ARE TO ACCOMPANY
THIS WAVE AS IT MOVES ACROSS THE NORTHEAST CARIBBEAN. ACROSS THE
LEEWARD/VIRGIN ISLES AND PUERTO RICO EXPECTING RAINFALL AMOUNTS OF
10-15MM/DAY AND MAXIMA OF 20-40MM.

TROPICAL WAVE ALONG 49W IS TO MOVE ACROSS THE GUIANAS DURING THE
DAY TODAY TO FAVOR RAINFALL AMOUNTS OF 05-10MM/DAY AND MAXIMA OF
15MM. THE WAVE ENTERS THE ISLAND CHAIN LATER ON FRIDAY TO TRIGGER
RAINFALL AMOUNTS OF 00-05MM/DAY AND MAXIMA OF 10MM. ACROSS
HISPANIOLA THIS IS TO THEN FAVOR RAINFALL AMOUNTS OF 05-10MM/DAY
AND MAXIMA OF 15-20MM.

AN EASTERLY WAVE ALONG 82W MOVES ACROSS COSTA RICA TO NICARAGUA
LATER TODAY...TO TRIGGER RAINFALL AMOUNTS OF 15-20MM/DAY AND
MAXIMA OF 25-50MM. ACROSS NORTHEAST HONDURAS/NICARAGUA EXPECTING
RAINFALL AMOUNTS OF 10-15MM/DAY AND MAXIMA OF 20-35MM...WHILE OVER
HONDURAS-EL SALVADOR AND INTO THE YUCATAN EXPECTING RAINFALL
AMOUNTS OF 10-15MM/DAY AND MAXIMA OF 20-35MM.

ANOTHER EASTERLY WAVE LIES ALONG 92W...PHASING WITH TUTT ALOFT
OVER THE GULF. AS THEY INTERACT...THIS WILL SUSTAIN SCATTERED
CONVECTION ACROSS THE SOUTHERN TO THE CENTRAL STATES OF
MEXICO...TO TRIGGER RAINFALL AMOUNTS OF 10-15MM/DAY AND MAXIMA OF
20-30MM. ACROSS SOUTHWEST MEXICO THIS INCREASES TO 10-15MM/DAY AND
MAXIMA OF 20-40MM.

CABANERIT...INAMEH (VENEZUELA)
CONTRERAS...IMN (COSTA RICA)
CASTILLO...UCR (COSTA RICA)
DAVISON...WPC (USA)
$$




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