Prognostic Meteorological Discussion
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FXCA20 KWBC 041654
PMDCA

TROPICAL DISCUSSION - INTERNATIONAL DESKS
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
1253 PM EDT FRI SEP 04 2015

LAST NO AMENDS...NEXT ON SEPTEMBER 08.

AT 15 UTC TROPICAL STORM KEVIN CENTERED NEAR 21.2N 115.2W...WITH
MAXIMUM SUSTAINED WINDS OF 50KT AND CENTRAL PRESSURE OF 998 HPA.
THE STORM IS MOVING TO THE NORTH AT 07KT. SEE NHC BULLETING FOR
OFFICIAL FORECAST.

DISCUSSION FROM SEP 04/12 UTC: A 250 HPA HIGH OVER THE TEXAS
PANHANDLE ANCHORS A RIDGE OVER THE WESTERN USA-NORTHERN STATES OF
MEXICO. THIS RIDGE IS TO HOLD NEARLY UNCHANGED OVER THE NEXT FEW
DAYS. MEANWHILE...IT IS TO VENT DIURNAL CONVECTION ALONG THE
SIERRA MADRE OCCIDENTAL...WHERE WE EXPECT
RAINFALL AMOUNTS OF 05-10MM/DAY AND MAXIMA OF 15-20MM. TS KEVIN
MEANDERS TO THE SOUTH OF THIS RIDGE...WITH THE NHC FORECASTING
THIS STORM TO GRADUALLY WEAKEN TO A DEPRESSION DURING THE DAY ON
SATURDAY. AS THE STORM WEAKENS THE RIDGE IS TO THEN ADVECT
MOISTURE NORTH ACROSS THE BAJA PENINSULA...TO GRADUALLY FAVOR AN
INCREASE IN CONVECTION ON THE SIERRA MADRE THROUGH SUNDAY. DURING
THAT PERIOD EXPECTING RAINFALL AMOUNTS OF 05-10MM/DAY AND MAXIMA
OF 15-25MM.

THE RIDGE IS TO ALSO STEER A WANING TUTT ACROSS CENTRAL MEXICO.
LATER THIS AFTERNOON THE TUTT LOW MOVES ACROSS
COLIMA-NAYARIT...WITH RIDGE PATTERN TO THEN BUILD SOUTH ACROSS
NORTHERN MEXICO. EARLY IN THE CYCLE THE WANING TUTT WILL ENHANCE
CONVECTION OVER THE SOUTHWEST-CENTRAL STATES OF MEXICO TO FAVOR
RAINFALL AMOUNTS OF 15-20MM/DAY AND MAXIMA OF 25-50MM. BUT AS THE
TROUGH MOVES AWAY THIS WILL DECREASE TO 10-15MM/DAY AND MAXIMA OF
20-45MM.

THE RIDGE IS TO ALSO FAVOR THE SOUTHWARD AMPLIFICATION OF A TROUGH
ACROSS THE SOUTHEAST USA TO THE EASTERN GULF LATER TODAY. THROUGH
SATURDAY MORNING THIS IS TO THEN PHASE WITH ANOTHER TUTT LOW THAT
MEANDERS OVER BELIZE/ YUCATAN. THROUGH SATURDAY EVENING/EARLY
SATURDAY MORNING THESE WILL COMBINE INTO A HIGH AMPLITUDE TROUGH
ACROSS THE FLORIDA PENINSULA-THE YUCATAN TO SOUTHERN
MEXICO/GUATEMALA. THE TUTT AND THE AMPLIFYING TROUGH WILL ENHANCE
DIURNAL CONVECTION ACROSS THE SOUTHERN STATES OF
MEXICO-GUATEMALA-BELIZE TO WESTERN PORTIONS OF HONDURAS. IN THIS
AREA EXPECT RAINFALL AMOUNTS OF 15-20MM/DAY AND MAXIMA OF 25-50MM.
THE TUTT LOW IS TO ALSO ENHANCE DIURNAL CONVECTION ACROSS
CENTRAL/WESTERN CUBA THROUGH THIS AFTERNOON...TO FAVOR RAINFALL
AMOUNTS OF 05-10MM/DAY AND MAXIMA OF 15-25MM. ON SATURDAY TO
SUNDAY MOST ACTIVE IS TO THEN CLUSTER OVER WESTERN CUBA WITH
RAINFALL AMOUNTS OF 05-10MM/DAY AND MAXIMA OF 15-25MM.

A THIRD TUTT LOW TO THE EAST MEANDERS OVER PUERTO RICO WHILE
EXTENDING A SHORT WAVE TROUGH TO VENEZUELA. A BUILDING CELL OF THE
SUBEQUATORIAL RIDGE OVER THE CENTRAL ATLANTIC IS TO THEN DISPLACE
THIS TUTT WEST AND NORTH AS IT AMPLIFIES INTO THE EASTERN
CARIBBEAN. EARLY IN THE CYCLE THE ISLANDS OF PUERTO RICO AND
HISPANIOLA WILL LIE ON THE CONVERGENT/SUBSIDENT SIDE OF THIS
TROUGH. BUT AS THE AXIS RETROGRESSES ENVIRONMENTAL CONDITIONS ARE
TO BECOME MORE FAVORABLE FOR CONVECTION TO DEVELOP. THE MEANDERING
TUTT ALOFT WILL COMBINE WITH LIGHT EASTERLY TRADES ACROSS THE
LESSER ANTILLES-PUERTO RICO TO FAVOR A GRADUAL INCREASE IN
DIURNAL/SEA BREEZE RELATED CONVECTION. ACROSS THE LEEWARD ISLES IT
IS TO FAVOR TRACE RAINFALL AMOUNTS...WHILE OVER PUERTO RICO-THE
DOMINICAN REPUBLIC EXPECTING RAINFALL ACCUMULATION OF 05-10MM/DAY
AND MAXIMA OF 15MM...INCREASING TO MAXIMA OF 15-20MM/DAY LATER IN
THE CYCLE. FAVORABLE UPPER CONDITIONS...HOWEVER...WILL BE SHORT
LIVED...WITH BUILDING RIDGE TO THEN STRENGTHEN ITS FOOTHOLD ACROSS
THE EASTERN CARIBBEAN ISLES THROUGH MIDDAY ON MONDAY. THIS IS TO
THEN FAVOR A DRYING TREND ACROSS THE NORTHEAST CARIBBEAN ISLES.

TROPICAL/EASTERLY WAVES INITIALIZED AT 12UTC
INITIAL  24     36     48     60     72     84     96        TYPE
51W     54W    58W    61W    64W    66W    69W    72W        TW
80W     83W    86W    89W    90W    93W    96W    98W        TW
91W     94W    96W    98W   101W   104W   107W   110W        TW
102W   103W   105W   108W   110W   112W   115W   118W        TW

TROPICAL WAVE ALONG 51W IS TO FAVOR ISOLATED TO SCATTERED COASTAL
CONVECTION ACROSS THE GUIANAS THROUGH SATURDAY MORNING...WITH
RAINFALL AMOUNTS OF 05-10MM/DAY AND MAXIMA OF 15-20MM. ACROSS THE
ISLAND CHAIN IT IS TO THEN TRIGGER TRACE RAINFALL AMOUNTS...WITH
MOST ACTIVE ON THE LEEWARD ISLES WHERE WE EXPECT TRACE RAINFALL
AMOUNTS. THROUGH MIDDAY ON SUNDAY THIS WILL SPREAD ACROSS THE
VIRGIN ISLES TO PUERTO RICO WHERE IT WILL FAVOR RAINFALL AMOUNTS
OF 05-10MM/DAY AND MAXIMA OF 15-20MM. OVER EASTERN-CENTRAL
VENEZUELA...IN INTERACTION WITH THE NET...EXPECTING RAINFALL
AMOUNTS OF 05-10MM/DAY AND MAXIMA OF 15-25MM.

TROPICAL WAVE ALONG 80W IS TO INTERACT WITH THE ITCZ OVER
PANAMA-COSTA RICA-SOUTHERN NICARAGUA TO TRIGGER RAINFALL AMOUNTS
OF 10-15MM/DAY AND MAXIMA OF 20-45MM. ACROSS THE CAYMAN ISLES THIS
IS TO ONLY FAVOR TRACE RAINFALL AMOUNTS. ACROSS EASTERN
NICARAGUA/NORTHEAST HONDURAS IT IS TO THEN TRIGGER RAINFALL
AMOUNTS OF 10-15MM/DAY AND MAXIMA OF 20-45MM...WHILE OVER SOUTHERN
HONDURAS-EL SALVADOR/GUATEMALA EXPECT RAINFALL AMOUNTS OF
10-15MM/DAY AND MAXIMA OF 20-45MM THROUGH MIDDAY ON SATURDAY.
ACROSS SOUTHERN MEXICO THIS IS TO THEN FAVOR SIMILAR AMOUNTS.

TROPICAL WAVE ALONG 91W IS TO TRIGGER SCATTERED CONVECTION ON THE
SOUTHERN TO CENTRAL STATES OF MEXICO OVER THE NEXT COUPLE OF
DAYS...TO RESULT IN RAINFALL AMOUNTS OF 15-20MM/DAY AND MAXIMA OF
25-50MM.

TROPICAL WAVE ALONG 102W IS EXITING THE DOMAIN.

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

$$





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