Prognostic Meteorological Discussion
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FXCA20 KWBC 311822
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TROPICAL DISCUSSION - INTERNATIONAL DESKS
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
222 PM EDT MON AUG 31 2015

DISCUSSION FROM AUG 31/12 UTC: UNDER INFLUENCE OF A RIDGE TO THE
WEST A MID LEVEL TROUGH IS TO DEEPEN ACROSS TEXAS TO THE NORTHEAST
STATES OF MEXICO. PATTERN IS TO THEN HOLD FOR THE NEXT THREE DAYS.
AT 250 HPA A 40-45KT JET MAXIMA ARE TO REVOLVE AROUND THIS
AXIS...TO FAVOR AREAS OF DIVERGENCE ALOFT AS IT ROUNDS THE BASE OF
THE TROUGH. THIS WILL COMBINE WITH DIURNAL HEATING/SEA BREEZE
CONVERGENCE TO LIKELY FAVOR STRONG/POTENTIALLY SEVERE CONVECTION.
ACROSS NORTHEAST MEXICO EXPECTING RAINFALL AMOUNTS OF 15-20MM/DAY
AND MAXIMA OF 30-60MM THROUGH TUESDAY MORNING...AND 05-10MM/DAY
AND MAXIMA OF 15-25MM THEREAFTER. ON THE CENTRAL-SOUTHWEST STATES
OF MEXICO...MEANWHILE EXPECTING RAINFALL AMOUNTS OF 15-20MM/DAY
AND MAXIMA OF 30-60MM. FURTHERMORE...STRONG TOPOGRAPHICAL FORCING
ON THE CENTRAL STATES OF MEXICO ARE LIKELY TO RESULT IN LOCALLY
HIGHER AMOUNTS IN EXCESS OF FORECAST GUIDANCE. ON THE
NORTHWEST...MEANWHILE...DIURNAL CONVECTION IS TO ONLY FAVOR
RAINFALL AMOUNTS OF 05-10MM/DAY AND MAXIMA OF 15-20MM.

DOWNSTREAM FROM THE UPPER TROUGH...BROAD CELL OF THE SUBTROPICAL
RIDGE EXTENDS OVER THE WESTERN ATLANTIC-FLORIDA PENINSULA TO THE
YUCATAN/NORTHWEST CARIBBEAN. THE RIDGE ANCHORS ON A CLOSED HIGH
JUST NORTH OF GRAND BAHAMA...WHERE IT IS TO GENERALLY REMAIN OVER
THE NEXT FEW DAYS WHILE THE RIDGE GRADUALLY BUILDS. A TUTT BOUNDS
THE SOUTHERN FRINGES OF THIS RIDGE...WITH AXIS WEST-SOUTHWEST
ALONG 23N 60W...HAITI TO A LOW/TROUGH OVER THE CENTRAL CARIBBEAN.
THE RIDGE TO THE NORTH IS FORECAST TO BUILD OVER THE NEXT COUPLE
OF DAYS. AS IT STRENGTHENS...THIS WILL DISPLACE THE TUTT SOUTH TO
THE NORTHERN LEEWARD ISLES/NORTHEAST CARIBBEAN EARLY ON WEDNESDAY
MORNING. THE LOW...MEANWHILE...RETROGRESSES TO THE NORTHWEST
CARIBBEAN LATER ON WEDNESDAY. MID/UPPER LEVEL RIDGE PATTERN...AS
IT MEANDERS OVER THE BAHAMAS IT IS TO GENERALLY FAVOR A FAIRLY
STRONG CAP INVERSION...THAT IS EXPECTED TO INHIBIT ORGANIZED
CONVECTION OVER THE NEXT FEW DAYS.

RETROGRESSING TUTT LOW IS TO ENHANCE CONVECTION ACROSS HISPANIOLA
EARLY IN THE CYCLE. BUT AS THE RIDGE BUILDS AND CAP STRENGTHENS
EXPECTING A DECREASE IN CONVECTION. CONVECTIVE ENHANCEMENT IS ALSO
EXPECTED ACROSS JAMAICA THROUGH THIS EVENING...AS THE TUTT
ENHANCES CONVECTION IN ASSOCIATION WITH A TROPICAL WAVE (SEE
BELOW). OVER THE CAYMAN ISLES EXPECTING RAINFALL AMOUNTS OF
05-10MM/DAY AND MAXIMA OF 15-25MM...WITH MOST INTENSE EXPECTED
TODAY. ACROSS CUBA...MEANWHILE...EXPECTING RAINFALL AMOUNTS OF
10-15MM/DAY AND MAXIMA OF 20-45MM. ON TUESDAY THIS DECREASES TO
05-10MM/DAY AND MAXIMA OF 15-25MM. ACROSS NICARAGUA-HONDURAS-EL
SALVADOR TO BELIZE AND GUATEMALA THE RETROGRESSING TUTT IS TO
ENHANCE DIURNAL CONVECTION. IN THIS AREA EXPECTING RAINFALL
AMOUNTS OF 05-10MM/DAY AND MAXIMA OF 15-25MM. OVER COSTA
RICA-PANAMA EXPECT POSITIVE INTERACTION WITH THE EASTERN PACIFIC
ITCZ TO RESULT IN RAINFALL AMOUNTS OF 05-10MM/DAY AND MAXIMA OF
15-25MM...WITH HIGHER AMOUNTS WITH TROPICAL WAVES. THIS IS TO ALSO
ENHANCE DIURNAL CONVECTION ACROSS WESTERN-NORTHERN
COLOMBIA...WHERE IN INTERACTION WITH THE PANAMANIAN LOW EXPECT
RAINFALL AMOUNTS OF 15-20MM/DAY AND MAXIMA OF 25-50MM.

VENEZUELA AND THE GUIANAS ARE TO REMAIN UNDER THE INFLUENCE OF THE
SUBEQUATORIAL RIDGE. BUT CONVECTIVE ENHANCEMENT IS TO GENERALLY
LIMIT TO THE NEAR EQUATORIAL TROUGH OVER VENEZUELA WHERE WE EXPECT
RAINFALL AMOUNTS OF 05-10MM/DAY AND MAXIMA OF 15-20MM. ACROSS THE
GUIANAS WIDELY ISOLATED COASTAL CONVECTION IS EXPECTED OVER THE
NEXT FEW DAYS.

TROPICAL/EASTERLY WAVES INITIALIZED AT 12UTC
INITIAL  24     36     48     60     72     84     96        TYPE
57W     60W    63W    66W    69W    72W    75W    78W        TW
70W     73W    76W    79W    82W    85W    88W    91W        TW
85W     88W    91W    93W    95W    98W   100W   102W        TW
106W   108W   111W   113W  EXITS DOMAIN                      TW

TROPICAL WAVE ALONG 57W IS TO INTERACT WITH TUTT OVER THE
NORTHEAST CARIBBEAN...WITH UPPER LEVEL FEATURE TO SUSTAIN A
DIVERGENT PATTERN THAT IS TO VENT CONVECTION AS IT ENTERS THE
ISLAND CHAIN LATER TODAY. ACROSS THE LESSER ANTILLES EXPECTING
RAINFALL AMOUNTS OF 10-15MM/DAY AND MAXIMA OF 20-35MM IN SLIGHT
RISK OF SEVERE CONVECTION. OVER PUERTO RICO-EASTERN HISPANIOLA
EXPECTING RAINFALL AMOUNTS OF 10-15MM/DAY AND MAXIMA OF 20-30MM IN
A SLIGHTLY HIGHER RISK OF SEVERE WEATHER TO DEVELOP DURING THE
AFTERNOON HOURS. ACROSS HAITI THIS IS TO THEN FAVOR RAINFALL
AMOUNTS OF 05-10MM/DAY AND MAXIMA OF 15MM...WHILE OVER
JAMAICA-HAITIAN PENINSULA EXPECT RAINFALL AMOUNTS OF 05-10MM/DAY
AND MAXIMA OF 15-20MM. ACROSS VENEZUELA...IN INTERACTION WITH THE
NEAR EQUATORIAL TROUGH...EXPECT RAINFALL AMOUNTS OF 05-10MM/DAY
AND MAXIMA OF 15-20MM. HIGHER AMOUNTS ARE EXPECTED TO THE
NORTHWEST/NORTHERN COLOMBIA LATER ON WEDNESDAY...WITH RAINFALL
AMOUNTS OF 15-20MM/DAY AND MAXIMA OF 25-50MM.

TROPICAL WAVE ALONG 70W IS IN PHASE WITH THE CENTRAL CARIBBEAN
TUTT LOW. THIS IS TO ENHANCE CONVECTION ACROSS HISPANIOLA DURING
THE DAY TODAY...TO FAVOR RAINFALL AMOUNTS OF 05-10MM/DAY AND
MAXIMA OF 15-20MM. ACROSS JAMAICA IT IS TO THEN SUSTAIN RAINFALL
AMOUNTS OF 05-10MM/DAY AND MAXIMA OF 15-25MM ON TUESDAY...WHILE
OVER THE CAYMAN ISLES EXPECT RAINFALL AMOUNTS OF 05-10MM/DAY AND
MAXIMA OF 15-20MM. STRONG POSITIVE INTERACTION ACROSS CUBA IS TO
THEN RESULT IN RAINFALL AMOUNTS OF 10-15MM/DAY AND MAXIMA OF
20-45MM DURING THE DAY ON TUESDAY. ACROSS COLOMBIA TO EASTERN
PANAMA EXPECT RAINFALL AMOUNTS OF 15-20MM/DAY AND MAXIMA OF
25-50MM WHILE ALSO INDUCING GRADUAL INTENSIFICATION OF THE
PANAMANIAN LOW. OVER WESTERN PANAMA-COSTA RICA TO SOUTHERN
NICARAGUA EXPECT RAINFALL AMOUNTS OF 15-20MM/DAY AND MAXIMA OF
25-50MM.

TROPICAL WAVE ALONG 85W IS TO TRIGGER SCATTERED DEEP CONVECTION
ACROSS WESTERN CUBA TO THE NORTHEAST YUCATAN PENINSULA...TO FAVOR
RAINFALL AMOUNTS OF 10-15MM/DAY AND MAXIMA OF 20-45MM. ACROSS EL
SALVADOR-HONDURAS TO GUATEMALA THIS IS TO THEN FAVOR RAINFALL
AMOUNTS OF 05-10MM/DAY AND MAXIMA OF 15-25MM. ON THE SOUTHERN
STATES OF MEXICO EXPECTING RAINFALL AMOUNTS OF 10-15MM/DAY AND
MAXIMA OF 20-45MM DURING THE DAY ON TUESDAY...WHILE ON THE CENTRAL
STATES MOST ACTIVE IS EXPECTED ON WEDNESDAY WHEN IT IS TO FAVOR
RAINFALL AMOUNTS OF 15-20MM/DAY AND MAXIMA OF 30-60MM.

TROPICAL WAVE ALONG 106W IS TO ENHANCE CONVECTION ACROSS SOUTHWEST
MEXICO EARLY IN THE CYCLE...TO FAVOR RAINFALL AMOUNTS OF
10-15MM/DAY AND MAXIMA OF 20-45MM.

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

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