Prognostic Meteorological Discussion
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FXCA20 KWBC 271803
PMDCA

TROPICAL DISCUSSION - INTERNATIONAL DESKS
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
203 PM EDT WED JUL 27 2016

TROPICAL DISCUSSION FROM JULY 27/12UTC: AT MID/UPPER LEVELS...CELL
OF THE SUBTROPICAL RIDGE MEANDERS OVER THE WESTERN USA. A
NARROW/ELONGATED TROUGH BOUNDS THE EASTERN FRINGES OF THIS
RIDGE...AS IT EXTENDS TO THE SOUTHWEST ACROSS LOUISIANA-TEXAS TO
THE NORTHEAST STATES OF MEXICO. UNDER INFLUENCE OF THE RIDGE THE
TROUGH IS TO SLOWLY SHEAR SHORT WAVE ENERGY ACROSS THE NORTHERN
STATES OF MEXICO. THE INFLOW OF COOLER AIR ALOFT AND CYCLONIC
VORTICITY WILL ENHANCE DIURNAL CONVECTION OVER NORTHERN MEXICO.
ACROSS TAMAULIPAS-COAHUILA THIS IS TO FAVOR RAINFALL AMOUNTS OF
10-15MM/DAY AND MAXIMA OF 20-35MM THROUGH THURSDAY...DECREASING TO
05-10MM/DAY AND MAXIMA OF 15MM ON THURSDAY TO FRIDAY. HIGHER
AMOUNTS ARE EXPECTED ALONG THE SIERRA MADRE OCCIDENTAL...WITH
ACCUMULATION OF 10-15MM/DAY AND MAXIMA OF 20-40MM. ON THURSDAY
THIS INCREASES TO 15-20MM/DAY AND MAXIMA OF 35-70MM IN ORGANIZED
DEEP CONVECTION...WHILE ON FRIDAY THE MAXIMA PEAKS AT 25-50MM. ON
THE SIERRA MADRE DEL SUR AND THE CENTRAL STATES EXPECTING RAINFALL
AMOUNTS OF 05-10MM/DAY AND MAXIMA OF 15-25MM OVER THE NEXT THREE
DAYS.

ANOTHER CELL OF THE SUBTROPICAL RIDGE LIES TO THE EAST...WITH
MID/UPPER LEVEL AXIS EXTENDING OVER THE EASTERN USA/WESTERN
ATLANTIC AND INTO THE NORTHERN CARIBBEAN ISLES. THROUGH FRIDAY
EVENING THE RIDGE BUILDS TO THE WEST-SOUTHWEST ACROSS THE
SOUTHEAST USA TO THE GULF OF MEXICO. THE MID/UPPER LEVEL RIDGE IS
TO FAVOR A MID LEVEL CAP INVERSION ACROSS THE BAHAMAS AND THE
GREATER ANTILLES. THIS CAP IS TO PERSIST OVER THE NEXT FEW
DAYS...WITH SHALLOW MOISTURE CONFINING TO LOWER LEVELS OF THE
ATMOSPHERE. AT LOW LEVELS THE RIDGE ALOFT SUSTAINS A BROAD RIDGE
NORTH OF THE ISLANDS AND A TIGHT GRADIENT/BRISK EASTERLY TRADES
ACROSS THE BASIN. THROUGH THE END OF THE WEEK THE RIDGE PATTERN
WEAKENS AND THE EASTERLIES ARE TO WANE. MEANWHILE...THIS IS TO
FAVOR GENERATION OF STREAMERS ACROSS THE ISLAND CHAIN THAT ARE TO
AFFECT THE VIRGIN ISLES-EASTERN PUERTO RICO FROM TIME TO TIME.

AS THE RIDGE BUILDS ACROSS THE SOUTHERN USA/GULF OF MEXICO...IT IS
TO DISPLACE A TUTT. EARLY IN THE CYCLE THE TUTT IS TO EXTEND NORTH
ACROSS THE YUCATAN TO THE EASTERN GULF. THROUGH THURSDAY EVENING
IT MOVES TO THE CAMPECHE SOUND/GULF COAST OF MEXICO...AND THEN
INLAND INTO NORTHEAST MEXICO LATER IN THE CYCLE. ACROSS
BELIZE/GUATEMALA-THE YUCATAN THIS IS TO FAVOR RAINFALL AMOUNTS OF
05-10MM/DAY AND MAXIMA OF 15MM. THROUGH FRIDAY THE MAXIMA
INCREASES TO 15-20MM. ON THE SOUTHERN TO CENTRAL STATES OF MEXICO
THIS IS TO THEN FAVOR RAINFALL AMOUNTS OF 05-10MM/DAY AND MAXIMA
OF 15-25MMM.

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. IT IS TO ALSO VENT DIURNAL CONVECTION ACROSS COLOMBIA TO
FAVOR RAINFALL AMOUNTS OF 05-10MM/DAY. HIGHER
AMOUNTS...HOWEVER...ARE EXPECTED ALONG THE WEST COAST WHERE THE
PANAMANIAN TROUGH IS TO SUSTAIN A MOIST/ONSHORE FLOW. IN THIS AREA
EXPECTING RAINFALL AMOUNTS OF 15-20MM/DAY AND MAXIMA OF 25-50MM.
THROUGH FRIDAY THE MAXIMA DECREASES TO 20-40MM.

A RETROGRESSING TUTT LOW LIES TO THE NORTH-NORTHEAST OF THE LESSER
ANTILLES...WHILE ANOTHER EXTENDS OVER THE EASTERN CARIBBEAN.
THROUGH FRIDAY THESE ARE TO MERGE INTO A BROAD TROUGH OVER THE
CENTRAL CARIBBEAN. AT MID LEVELS THE NORTHERNMOST WILL SUSTAIN AN
INDUCED/INVERTED TROUGH ACROSS THE ISLAND CHAIN EARLY ON
THURSDAY...THAT PULLS ACROSS THE VIRGIN ISLES/PUERTO RICO LATER
DURING THE DAY. THIS MOVES WEST ACROSS HISPANIOLA TO THE CENTRAL
CARIBBEAN ON FRIDAY. THIS IS STRONG ENOUGH TO BREACH THE CAP
INVERSION ACROSS THE NORTHEAST CARIBBEAN ISLES. OVER VENEZUELA
THIS IS TO VENT CONVECTION ALONG THE NEAR EQUATORIAL TROUGH TO
RESULT IN RAINFALL AMOUNTS OF 10-15MM/DAY AND MAXIMA OF 20-40MM.
THROUGH FRIDAY IT WILL GRADUALLY DECREASE TO 05-10MM/DAY AND
MAXIMA OF 15-25MM. ACROSS THE LEEWARD/FRENCH ISLES TO PUERTO RICO
IT IS TO FAVOR RAINFALL AMOUNTS OF 00-05MM/DAY AND MAXIMA OF
10MM...WHILE OVER HISPANIOLA EXPECTING RAINFALL AMOUNTS OF
05-10MM/DAY AND MAXIMA OF 15MM.

TROPICAL/EASTERLY WAVES INITIALED AT 12UTC.
INITIAL    24    36    48    60    72    84    96      TYPE
42W       45W   49W   53W   56W   60W   64W   68W      TW
52W       56W   60W   64W   68W   72W   76W   80W  TUTT INDUCED
74W       77W   80W   83W   86W   89W   92W   94W      EW
85W       88W   91W   94W   97W   99W  100W  102W      EW

TROPICAL WAVE IS INITIALIZED ALONG 42W. THIS PULLS NORTH OF THE
GUIANAS ON THURSDAY...WHERE IT IS TO MODULATE THE ITCZ WHILE
TRIGGERING SCATTERED SHOWERS WITH RAINFALL AMOUNTS OF 05-10MM/DAY
AND MAXIMA OF 15MM. IT MOVES ACROSS THE ISLAND CHAIN LATER ON
FRIDAY/EARLY MORNING ON SATURDAY TO TRIGGER RAINFALL AMOUNTS OF
00-05MM/DAY AND MAXIMA OF 10MM.

TUTT EAST OF THE ISLANDS SUSTAINS A PERTURBATION IN THE EASTERLY
TRADES. THIS MOVES TO THE LEEWARD/FRENCH ISLES ON THURSDAY MORNING
WHERE IT IS TO FAVOR RAINFALL AMOUNTS OF 00-05MM/DAY AND MAXIMA OF
10MM. ACROSS THE VIRGIN ISLES-PUERTO RICO THIS IS TO ALSO FAVOR
LIGHT RAINFALL AMOUNTS WITH ACCUMULATION OF 00-05MM/DAY AND MAXIMA
OF 10MM ON THURSDAY TO FRIDAY MORNING. CONVECTION IS TO THEN
SPREAD ACROSS THE MONA PASSAGE TO THE DOMINICAN REPUBLIC ON
FRIDAY...TO TRIGGER RAINFALL AMOUNTS OF 05-10MM/DAY AND MAXIMA OF
15MM.

AN EASTERLY WAVE ALONG 74W IS TO INTERACT WITH THE NET OVER
WESTERN COLOMBIA TO FAVOR RAINFALL AMOUNTS OF 10-15MM/DAY AND
MAXIMA OF 20-40MM. OVER JAMAICA IT IS TO FAVOR RAINFALL AMOUNTS OF
05-10MM/DAY AND MAXIMA OF 15-20MM. ACROSS PANAMA TO COSTA RICA AND
SOUTHERN NICARAGUA THIS IS TO THEN TRIGGER RAINFALL AMOUNTS OF
15-20MM/DAY AND MAXIMA OF 25-50MM ON THURSDAY. ACROSS NORTHEAST
HONDURAS/NICARAGUA EXPECTING RAINFALL AMOUNTS OF 10-15MM/DAY AND
MAXIMA OF 20-35MM...WHILE OVER HONDURAS-EL SALVADOR EXPECTING
RAINFALL AMOUNTS OF 05-10MM/DAY AND MAXIMA OF 15-20MM.

ANOTHER EASTERLY WAVE LIES ALONG 85W IS TO TRIGGER SCATTERED
CONVECTION ACROSS HONDURAS INTO BELIZE-GUATEMALA AND THE
YUCATAN...WHERE IT IS TO SUSTAIN RAINFALL AMOUNTS OF 05-10MM/DAY
AND MAXIMA OF 15MM. ON THE SOUTHERN STATES OF MEXICO AND ACROSS
THE VERACRUZ TO TAMAULIPAS THIS IS TO THEN TRIGGER RAINFALL
AMOUNTS OF 05-10MM/DAY AND MAXIMA OF 15MM ON THURSDAY. ON FRIDAY
THE FOCUS WOULD BE ON THE SOUTHWEST STATES WHERE WE EXPECT
RAINFALL AMOUNTS OF 05-10MM/DAY AND MAXIMA OF 15-25MM.

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




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