Prognostic Meteorological Discussion
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FXCA20 KWBC 231828
PMDCA

TROPICAL DISCUSSION - INTERNATIONAL DESKS
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
228 PM EDT TUE AUG 23 2016

AT 15 UTC...TD FIONA CENTERED NEAR 26.1N 64.5W...WITH MINIMAL
CENTRAL PRESSURE OF 1014 HPA AND MAXIMUM SUSTAINED WINDS OF 10KT.
THE TD IS MOVING WEST-NORTHWEST AT 10KT.

TS GASTON CENTERED NEAR 13.8N 34.6W...WITH MINIMAL CENTRAL
PRESSURE OF 1002 HPA AND MAXIMUM SUSTAINED WINDS OF 55KT. THE
STORM IS MOVING WEST-NORTHWEST AT 18KT.

TROPICAL DISCUSSION FROM AUG 23/00UTC: AT MID/UPPER LEVELS A BROAD
CELL OF THE SUBTROPICAL RIDGE DOMINATES THE FLOW ACROSS THE
SOUTHEAST USA-GULF OF MEXICO WHILE ANCHORING ON A 500 HPA HIGH
THAT IS TO MEANDER OVER GEORGIA/ALABAMA. THE RIDGE WILL BE STRONG
ENOUGH TO DELAY THE ONSET OF DIURNAL CONVECTION ACROSS CUBA AND
THE BAHAMAS...BUT WILL NOT BE STRONG ENOUGH TO SUPPRESS IT. OVER
THE NORTHWEST BAHAMAS EXPECTING RAINFALL AMOUNTS OF 05-10MM/DAY
AND MAXIMA OF 15MM THROUGH THURSDAY. OVER WESTERN CUBA EXPECTING
MOST ACTIVE ON WEDNESDAY TO THURSDAY WITH RAINFALL AMOUNTS OF
05-10MM/DAY AND MAXIMA OF 15MM.

A MID/UPPER LEVEL TROUGH OVER THE WESTERN USA WILL PRESS AGAINST
THE SUBTROPICAL RIDGE. THE WELL ENTRENCHED RIDGE IS EXPECTED TO
HOLD...IF NOT INTENSIFY...THROUGH THE MEDIUM RANGE PERIOD. AS A
RESULT...THE TROUGH IS TO STALL WHILE MEANDERING ACROSS THE
WESTERN USA TO THE NORTHWEST STATES OF MEXICO. A MEANDERING TUTT
LIES TO THE SOUTH OF THIS TROUGH...SUSTAINING AN INDUCED INVERTED
TROUGH INTO SOUTHERN BAJA PENINSULA-SINALOA IN WESTERN MEXICO.
UNDER INFLUENCE OF TROUGH TO THE NORTH...THE TUTT IS TO SLOWLY
SHEAR...WITH AXIS TO MERGE INTO THE LONG WAVE TROUGH LATER IN THE
CYCLE. AS THEY INTERACT...THESE WILL ENHANCE DIURNAL CONVECTION
ACROSS THE WESTERN STATES OF MEXICO...WITH MOST ACTIVE TO SPLIT
BETWEEN THE SIERRA MADRE DEL SUR AND THE SIERRA MADRE OCCIDENTAL.
IN THIS AREA EXPECTING RAINFALL AMOUNTS OF 10-15MM/DAY AND MAXIMA
OF 20-40MM. THROUGH THURSDAY EXPECTING A SLIGHT DECREASE WITH
MAXIMA TO PEAK AT 20-35MM LATER IN THE CYCLE.

ANOTHER TUTT EXTENDS FROM THE WESTERN CARIBBEAN TO THE SOUTHERN
GULF OF MEXICO/VERACRUZ. THIS TROUGH IS TO BOUND THE SOUTHERN
FRINGES OF THE SUBTROPICAL RIDGE DURING THE NEXT FEW DAYS. AS IT
STRADDLES OFF THE COAST OF HONDURAS INTO THE YUCATAN THIS WILL
ENHANCE DIURNAL CONVECTION. OVER NORTHERN HONDURAS-NORTHEAST
NICARAGUA THIS WILL SUSTAIN RAINFALL AMOUNTS OF 05-10MM/DAY AND
MAXIMA OF 15MM. ACROSS EL SALVADOR-SOUTHERN HONDURAS EXPECTING AN
INCREASE IN CONVECTION THROUGH THURSDAY WHEN WE EXPECT RAINFALL
AMOUNTS OF 10-15MM/DAY AND MAXIMA OF 20-35MM. OVER
GUATEMALA-BELIZE EXPECTING RAINFALL AMOUNTS OF 05-10MM/DAY AND
MAXIMA OF 15MM. OTHER ENHANCEMENT IS EXPECTED ACROSS VERACRUZ IN
NORTHEAST MEXICO...WHERE THE UPPER TROUGH WILL FAVOR RAINFALL
AMOUNTS OF 05-10MM/DAY AND MAXIMA OF 15MM. ON WEDNESDAY THIS IS TO
PEAK AT 15-20MM.

TROPICAL/EASTERLY WAVES INITIALIZED AT 12UTC

INITIAL    24      36      48      60      72      84      96
TYPE
56W       59W     63W     67W     69W     71W     75W     77W
TW
64W       67W     69W     72W     75W     77W     80W     82W
EW
71W       73W     74W     76W     79W     81W     DISSIPATES
EW
76W       78W     80W     82W     85W     88W     91W     93W
TUTT INDUCED
102W     105W    108W    110W    112W    114W    116W    118W
TUTT INDUCED

TROPICAL WAVE IS INITIALIZED ALONG 56W. SATELLITE DERIVED PWAT
ANALYSIS SHOWS MOISTURE CONTENT OF 50-75MM JUST EAST OF THE TROUGH
AXIS. THE PERTURBATION MOVES ACROSS THE FRENCH/LEEWARD ISLES LATER
THIS EVENING TO TRIGGER RAINFALL AMOUNTS OF 15-20MM/DAY AND MAXIMA
OF 25-50MM. ON WEDNESDAY TO THURSDAY IT WILL THEN FAVOR THE
NORTHWARD MODULATION OF THE ITCZ TO TRIGGER RAINFALL AMOUNTS OF
15-20MM/DAY AND MAXIMA OF 35-70MM. THIS BUILD ACROSS THE VIRGIN
ISLES TO NORTHEAST PUERTO RICO LATER ON WEDNESDAY...WHERE IT
FAVORS SIMILAR RAINFALL AMOUNTS. ON THURSDAY IT WILL DECREASE TO
10-15MM/DAY AND MAXIMA OF 20-40MM. ACROSS THE DOMINICAN REPUBLIC
IT IS TO THEN FAVOR RAINFALL AMOUNTS OF 10-15MM/DAY AND MAXIMA OF
20-35MM. OVER VENEZUELA...IN INTERACTION WITH THE NEAR EQUATORIAL
TROUGH...THIS WILL FAVOR RAINFALL AMOUNTS OF 10-15MM/DAY AND
MAXIMA OF 20-35MM.

AT 700 HPA...AN EASTERLY WAVE IS INITIALIZED ALONG 64W...INDUCED
BY TD FIONA TO THE NORTH. THE MID LEVEL PERTURBATION PULLS ACROSS
PUERTO RICO LATER THIS EVENING...TO MEANWHILE FAVOR RAINFALL
AMOUNTS OF 10-15MM/DAY AND MAXIMA OF 20-35MM. LOCALLY HIGHER
AMOUNTS ARE HIGHLY LIKELY AS ENHANCED BY LOCAL TERRAIN. SIMILAR
AMOUNTS ARE EXPECTED ACROSS THE DOMINICAN REPUBLIC-HAITI ON
WEDNESDAY.. ON THURSDAY THIS WILL AFFECT EASTERN CUBA-JAMAICA TO
TRIGGER RAINFALL AMOUNTS OF 05-10MM/DAY AND MAXIMA OF 15-25MM.
ACROSS VENEZUELA TO NORTHERN COLOMBIA...AS IT INTERACTS WITH THE
NEAR EQUATORIAL TROUGH...EXPECTING RAINFALL AMOUNTS OF 10-15MM/DAY
AND MAXIMA OF 20-40MM ON TUESDAY TO WEDNESDAY. ON WEDNESDAY TO
THURSDAY THE MID LEVEL TROUGH WILL INTERACT WITH THE PANAMANIAN
LOW TO SUSTAIN GRADUAL INTENSIFICATION OF THE LOW LEVEL
CIRCULATION. THIS WILL THEN ENHANCE ONSHORE FLOW ACROSS WESTERN
COLOMBIA/ANDEAN REGION. IN THIS AREA EXPECTING RAINFALL AMOUNTS OF
10-15MM/DAY AND MAXIMA OF 20-45MM. THIS BUILDS WEST ACROSS THE
DARIEN TO CENTRAL PANAMA LATER ON THURSDAY.

AN EASTERLY WAVE ALONG 71W MEANDERS OVER THE CENTRAL CARIBBEAN
WHILE GRADUALLY WEAKENING THROUGH FRIDAY MORNING. EARLY IN THE
CYCLE THIS WILL TRIGGER SCATTERED CONVECTION ACROSS HAITI-JAMAICA
TO RESULT IN RAINFALL AMOUNTS OF 10-15MM/DAY AND MAXIMA OF
20-35MM. IT IS TO ALSO ENHANCE CONVECTION ACROSS NORTHWEST
COLOMBIA/THE DARIEN IN EASTERN PANAMA TO RESULT IN RAINFALL
AMOUNTS OF 10-15MM/DAY AND MAXIMA OF 20-40MM THROUGH WEDNESDAY
MORNING. THE WAVE IS TO ALSO INTERACT WITH THE EASTERN PACIFIC
ITCZ TO SUSTAIN AFOREMENTIONED CONVECTION ACROSS PANAMA TO
NORTHWEST COLOMBIA. ACROSS COSTA RICA TO SOUTHERN NICARAGUA
EXPECTING RAINFALL AMOUNTS OF 10-15MM/DAY AND MAXIMA OF 20-35MM ON
WEDNESDAY TO THURSDAY AS IT INTERACTS WITH THE ITCZ.

THE TUTT OVER THE WESTERN CARIBBEAN SUSTAINS AN INDUCED/INVERTED
TROUGH IN THE LOW LEVEL EASTERLY TRADES...WITH AXIS NORTH ALONG
76W. AS IT MEANDERS ACROSS JAMAICA THIS WILL FAVOR RAINFALL
AMOUNTS OF 10-15MM/DAY AND MAXIMA OF 20-35MM. ACROSS THE CAYMAN
ISLES THIS WILL THEN FAVOR RAINFALL AMOUNTS OF 00-05MM/DAY AND
MAXIMA OF 10MM ON WEDNESDAY. AS IT ENTERS NORTHEAST
NICARAGUA/HONDURAS ON WEDNESDAY EXPECTING IT TO FAVOR RAINFALL
AMOUNTS OF 05-10MM/DAY AND MAXIMA OF 15MM. OVER BELIZE-YUCATAN IT
IS TO ALSO FAVOR RAINFALL AMOUNTS OF 05-10MM/DAY AND MAXIMA OF
15MM...WHILE OVER SOUTHERN HONDURAS/EL SALVADOR THIS INCREASES TO
10-15MM/DAY AND MAXIMA OF 20-35MM.

ANOTHER TUTT INDUCED TROUGH IS INITIALIZED AROUND 102W. THIS
PERTURBATION WILL ENHANCE DIURNAL CONVECTION ACROSS SOUTHWEST
MEXICO THROUGH WEDNESDAY EVENING...TO SUSTAIN RAINFALL AMOUNTS OF
10-15MM/DAY AND MAXIMA OF 20-40MM. NHC IS MONITORING THIS FEATURE
FOR POSSIBLE TROPICAL CYCLONE FORMATION.

CONTRERAS...IMN (COSTA RICA)
GALVEZ/DAVISON...WPC (USA)
$$





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