Prognostic Meteorological Discussion
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TROPICAL DISCUSSION - INTERNATIONAL DESKS
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
1258 PM EDT THU JUL 30 2015

DISCUSSION FROM JUL 30/12 UTC: NO CHANGES TO THE UPPER FLOW
PATTERN ACROSS WESTERN PORTIONS OF THE DOMAIN...AS A BROAD RIDGE
IS TO DOMINATE FLOW ACROSS THE SOUTHERN USA-NORTHERN STATES OF
MEXICO. AT 250 HPA THE RIDGE IS TO CENTER ON A HIGH THAT MEANDERS
OVER TEXAS. A TUTT TO THE SOUTH OF THIS RIDGE MEANDERS OFF THE
COAST OF COLIMA/NAYARIT. UNDER INFLUENCE OF THE RIDGE THIS IS TO
MIGRATE TO THE WEST-NORTHWEST ALONG THE COAST OF SOUTHERN BAJA
PENINSULA LATER THIS EVENING...AND FARTHER TO THE WEST EARLY ON
FRIDAY. EARLY IN THE CYCLE THIS IS LIKELY TO ENHANCE CONVECTION ON
THE SIERRA MADRE DEL SUR/SOUTHWEST STATES OF MEXICO...WHERE WE
EXPECT RAINFALL AMOUNTS OF 10-15MM/DAY AND MAXIMA OF 20-40MM. OVER
SINALOA-SONORA...MEANWHILE...DIURNAL CONVECTION IS TO SUSTAIN
RAINFALL AMOUNTS OF 05-10MM/DAY AND MAXIMA OF 15-25MM.

ANOTHER TUTT LOW DEVELOPED OVER THE NORTHWEST CARIBBEAN EARLY THIS
MORNING. THE LOW IS TO MEANDER OVER THE WESTERN CARIBBEAN WHILE
EXTENDING A TROUGH ACROSS GUATEMALA TO THE SOUTHERN STATES OF
MEXICO/NORTHERN CENTRAL AMERICA. THE LOW IS TO SLOWLY MIGRATE TO
THE SOUTHWEST ACROSS GUATEMALA TO SOUTHERN MEXICO THROUGH SUNDAY
EVENING. AS IT MEANDERS OVER THE WESTERN CARIBBEAN THE SHORT WAVE
TROUGH/TUTT LOW IS TO ENHANCE DIURNAL CONVECTION ACROSS
HONDURAS-GUATEMALA-BELIZE. THE MOST ACTIVE IS EXPECTED THROUGH
EARLY SATURDAY...WHEN WE EXPECT RAINFALL AMOUNTS OF 10-15MM/DAY
AND MAXIMA OF 20-40MM. OTHERWISE EXPECTING RAINFALL AMOUNTS OF
05-10MM/DAY AND MAXIMA OF 15MM.

AT MID LEVELS...A MEANDERING TROUGH LIES ACROSS THE FLORIDA
PENINSULA WHILE ORIGINATING ON A CLOSED LOW NORTH OF THE BAHAMAS.
THE TROUGH IS TO SLOWLY WEAKEN OVER THE NEXT FEW DAYS.
MEANWHILE...IT IS TO FOCUS SHORT WAVE ENERGY ACROSS BIMINI-GRAND
BAHAMA AND GREAT ABACO. BEST INFLOW OF ENERGY AND CONVECTIVE
INSTABILITY IS EXPECTED TODAY INTO EARLY FRIDAY MORNING...WITH
RAINFALL AMOUNTS OF 10-15MM/DAY AND MAXIMA OF 20-45MM. THROUGH
SATURDAY THIS DECREASES TO 05-10MM/DAY AND MAXIMA OF 15-25MM. OVER
NEW PROVIDENCE/ELEUTHERA TO NORTHERN ANDROS EXPECTING RAINFALL
AMOUNTS OF 05-10MM/DAY AND MAXIMA OF 15-25MM.

BUILDING MID LEVEL RIDGE IS TO THEN ESTABLISH A FOOTHOLD ACROSS
THE CENTRAL ATLANTIC TO THE NORTHERN CARIBBEAN ISLES. AT 250 HPA A
TUTT LOW TO THE NORTH OF THE TURKS AND CAICOS CONTINUES TO
RETROGRESS TOWARDS THE BAHAMAS. THE RETROGRESSING TUTT FAVORS AN
INDUCED/INVERTED MID LEVEL TROUGH ACROSS THE EASTERN CARIBBEAN.
UNDER INFLUENCE OF THE MID LEVEL RIDGE THE INVERTED TROUGH PULLS
ACROSS HISPANIOLA TO THE CENTRAL CARIBBEAN THROUGH FRIDAY
EVENING...THEN STARTS TO WEAKEN AS IT DECOUPLES FROM THE UPPER
LEVEL PERTURBATION. EARLY IN THE CYCLE THIS IS TO ENHANCE
INSTABILITY ACROSS THE SOUTHEAST CARIBBEAN/LESSER ANTILLES...WHERE
WE EXPECT RAINFALL AMOUNTS OF 15-20MM/DAY AND MAXIMA OF 25-50MM
THROUGH EARLY FRIDAY BETWEEN MARTINIQUE AND NORTHERN GRENADA.
BUILDING MID LEVEL RIDGE IS TO THEN REESTABLISH THE CAP INVERSION
ACROSS THE NORTHEAST CARIBBEAN ISLES THROUGH FRIDAY AFTERNOON
SETTING ONCE AGAIN UNSEASONABLY DRY CONDITIONS.

FARTHER EAST...MODELS FORECAST ANOTHER TUTT LOW TO CLOSE JUST
NORTH OF FRENCH GUIANA LATER ON THURSDAY. MODELS CONTINUE TO
FORECAST THIS FEATURE TO REMAIN NEARLY STATIONARY OFF THE COAST
THROUGH THE END OF THE WEEK. MEANWHILE...IT IS TO INTERACT WITH
THE ATLANTIC ITCZ/SEA BREEZE CONVERGENCE OVER THE NORTHERN
GUIANAS. INITIALLY EXPECT RAINFALL AMOUNTS OF 00-05MM/DAY AND
MAXIMA OF 10MM. THROUGH FRIDAY THIS INCREASES TO 05-10MM/DAY AND
MAXIMA OF 15MM.

TROPICAL/EASTERLY WAVES INITIALIZED AT 12UTC
INITIAL  24     36     48     60     72     84     96        TYPE
28W      30W    32W    35W    36W    39W    41W    43W       TW
70W      74W    77W    81W    84W    87W    90W    94W       TW
88W      91W    93W    96W    99W   103W   106W   109W       TW
99W     101W   104W   107W   110W   113W   115W   117W       TW

TROPICAL WAVE ALONG 28W IS TO CONFINE TO THE ATLANTIC ITCZ.

TROPICAL WAVE IS INITIALIZED ALONG 70W AND SOUTH OF 18N. THIS IS
INTERACTING WITH TUTT ALOFT IN SUPPORT OF ISOLATED TO SCATTERED
CONVECTION OVER THE EASTERN CARIBBEAN. BUT THE MOST ACTIVE IS TO
GENERALLY REMAIN TO THE SOUTH OF THE GREATER ANTILLES. ACROSS
EASTERN PUERTO RICO-VIRGIN ISLES INTO HISPANIOLA THIS IS TO FAVOR
MAXIMUM RAINFALL AMOUNTS 10-15MM. ACROSS NORTHWEST
VENEZUELA/NORTHERN COLOMBIA EXPECTING RAINFALL AMOUNTS OF
05-10MM/DAY AND MAXIMA OF 15-30MM THROUGH FRIDAY MORNING. ACROSS
PANAMA-COSTA RICA IT IS TO THEN TRIGGER RAINFALL AMOUNTS OF
10-15MM/DAY AND MAXIMA OF 20-35MM AS IT INTERACTS WITH THE ITCZ.
NORTH ALONG THIS AXIS...OVER JAMAICA-CENTRAL CUBA...EXPECTING
RAINFALL AMOUNTS OF 00-05MM/DAY AND MAXIMA OF 10MM ON
FRIDAY-SATURDAY...WHILE OVER NORTHEAST HONDURAS/EASTERN NICARAGUA
EXPECTING RAINFALL AMOUNTS OF 10-15MM/DAY AND MAXIMA OF 20-40MM.
OVER EL SALVADOR-GUATEMALA EXPECTING RAINFALL ACCUMULATION OF
05-10MM/DAY AND MAXIMA OF 15MM ON SATURDAY TO SUNDAY.

TROPICAL WAVE ALONG 88W IS INTERACTING WITH NORTHWEST CARIBBEAN
TUTT LOW. THIS IS TO ENHANCE CONVECTION ACROSS NORTHERN CENTRAL
AMERICA WHERE WE EXPECT RAINFALL AMOUNTS OF 10-15MM/DAY AND MAXIMA
OF 20-40MM THROUGH FRIDAY MORNING. OVER SOUTHERN MEXICO THIS IS TO
THEN FAVOR RAINFALL AMOUNTS OF 10-15MM/DAY AND MAXIMA OF 20-30
THROUGH SUNDAY.

TROPICAL WAVE ALONG 99W IS TO TRIGGER SCATTERED CONVECTION ACROSS
SOUTHWEST MEXICO EARLY IN THE CYCLE...WITH RAINFALL AMOUNTS OF
10-15MM/DAY AND MAXIMA OF 20-30MM.

SALMON...MS (ANTIGUA AND BARBUDA)
SAMUEL...MDS (SURINAME)
DAVISON...WPC (USA)
$$





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