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Tropical Discussion
 
(Caution: Version displayed is not the latest version. - Issued 1836Z Mar 25, 2015)
 
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TROPICAL DISCUSSION - INTERNATIONAL DESKS
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
236 PM EDT WED MAR 25 2015

DISCUSSION FROM MARCH 25/00 UTC:  LARGE LONG WAVE TROUGH
APPROACHING FROM THE WESTERN USA IS A FEATURE OF INTEREST. THIS
TROUGH IS FORECAST TO AMPLIFY AS IT MOVES INTO THE PLANS OF THE
USA AND INTO THE ATLANTIC. THE ROBUST TROUGH WILL SUSTAIN THE
DEVELOPMENT OF A POLAR HIGH AT LOW-LEVELS AND ASSOCIATED COLD
FRONT. THE FRONT WILL MOVE RAPIDLY INTO THE NORTHWESTERN GULF OF
MEXICO DURING THE DAY ON THURSDAY TO EXTEND INTO NORTHERN VERACRUZ
ON THURSDAY EVENING AND GULF OF CAMPECHE DURING FRIDAY
MORNING...NORTHERN YUCATAN-GULF OF CAMPECHE ON FRIDAY EVENING WHEN
TAIL WILL BECOME ILL-DEFINED. A 25-35KT NORTES EVENT IS ALSO
EXPECTED. THIS WILL LEAD TO A TEHUANTEPECER JET DEVELOPING DURING
THE DAY ON FRIDAY AND LASTING INTO SUNDAY. FOCUS FOR LARGEST
RAINFALL AMOUNTS WILL CONCENTRATE ACROSS THE EASTERN/NORTHEASTERN
SLOPES OF SOUTHEASTERN MEXICO ON THURSDAY MIGRATING SOUTHEAST INTO
NORTHERN GUATEMALA/CHIAPAS/BELIZE/YUCATAN ON FRIDAY. BY THURSDAY
INTO EARLY FRIDAY EXPECTING AMOUNTS OF 15-20MM/DAY AND MAXIMA OF
35-70MM/DAY ACROSS CENTRAL AND NORTHERN VERACRUZ. ACROSS
TAMAULIPAS EXPECTING ACCUMULATIONS OF 10-15MM/DAY AND ISOLATED
MAXIMA OF 20-30MM/DAY. BY FRIDAY INTO EARLY SATURDAY EXPECTING
AMOUNTS OF 15-20MM/DAY AND MAXIMA OF 40-80MM FROM
CHIAPAS/SOUTHEASTERN VERACRUZ INTO NORTHWESTERN
HONDURAS/BELIZE/NORTHERN GUATEMALA. ACROSS THE YUCATAN
PENINSULA...PRE-FRONTAL/FRONTAL THUNDERSTORMS ARE TO PRODUCE
MAXIMA OF 25-50MM/DAY. LIGHT RAIN SHOWERS AND ISOLATED
THUNDERSTORMS WILL ALSO DEVELOP ACROSS SOUTHERN GUATEMALA/WESTERN
EL SALVADOR ON FRIDAY AFTERNOON TO PRODUCE ISOLATED MAXIMA OF 15MM.

FRONT WILL ALSO ENHANCE ACTIVITY TO THE EAST ACROSS CUBA AND THE
BAHAMAS. LARGEST AMOUNTS WILL ARRIVE AND SPREAD DURING FRIDAY...TO
PRODUCE ACCUMULATIONS OF 10-15MM/DAY AND MAXIMA OF 20-25MM/DAY
INTO EARLY SATURDAY MORNING. AMOUNTS WILL MIGRATE TO THE SOUTHEAST
INTO SUNDAY WITH MOST WIDESPREAD ACTIVITY LIKELY AFFECTING
SOUTHEASTERN/CENTRAL CUBA...CENTRAL AND SOUTHEASTERN BAHAMAS/TURKS
AND CAICOS...AND THE CAYMAN ISLANDS/JAMAICA. THE ECMWF AND GFS
DIVERGE ON THE SPEED OF THE FRONT AFTER FRIDAY...THUS THE
PROGRESSION OF THE SYSTEM IS NOT TOTALLY CLEAR ONCE THE WEEKEND
ARRIVES.

IN THE CARIBBEAN BASIN...MID-UPPER RIDGE WILL CONTINUE DOMINATING
MOST OF THE REGION. THE RIDGE IS SUSTAINING A STRONG SUBSIDENCE
CAP ALONG THE NORTHERN CARIBBEAN. TO THE SOUTH OF 15N...THE
SUBSIDENCE CAP IS SLIGHTLY WEAKER...YET A VERY DRY AIR MASS OVER
700 HPA PERSISTS. THIS WILL CONTINUE LIMITING DEVELOPMENT TO
PASSING SHOWERS. A WEAKENING EASTERLY WAVE IS PROPAGATING INTO THE
BASIN (SEE BELOW) BUT ITS LOSING ITS EFFECTS ON PRECIPITATION.
TRAILING MOISTURE PLUME BEHIND THE WAVE AXIS WILL HOWEVER INCREASE
THE COVERAGE AND INTENSITY OF SHOWERS SLIGHTLY ACROSS THE WINDWARD
ISLANDS/TRINIDAD AND TOBAGO THROUGH EARLY THURSDAY TO PRODUCE
ISOLATED MAXIMA OF 15MM. THIS WILL ALSO ENHANCE ACTIVITY IN
NORTHERN GUYANA TO PRODUCE MAXIMA OF 15-20MM/DAY. AMOUNTS WILL
DECREASE AFTERWARDS...WITH LINGERING SCATTERED SHOWERS EXTENDING
FROM THE WINDWARD ISLANDS INTO THE ABC/NORTHERN COAST OF VENEZUELA
ON THURSDAY INTO FRIDAY...WITH ISOLATED MAXIMA OF 10MM EXPECTED.

ACROSS NORTHWESTERN SOUTH AMERICA...SEASONALLY QUIET PATTERN TO
CONTINUE ACROSS MOST OF COLOMBIA. MOST ACTIVE CONVECTION IS
EXPECTED ACROSS THE SOUTHWESTERN ANDES OF COLOMBIA INTO ECUADOR.
EXPECTING ACCUMULATIONS IN THE 05-10MM/DAY RANGE WITH ISOLATED
MAXIMA OF 15-25MM.

TROPICAL/EASTERLY WAVES INITIALIZED AT 12UTC
INITIAL  24     36     48     60     72     84     96        TYPE
63W     66W    69W    72W    75W     DISSIPATES              EW

EASTERLY WAVE INITIALIZED AT 63W IS WEAKENING AS IT MOVES ACROSS
THE SOUTHEASTERN CARIBBEAN. THIS WAVE IS HAVING LIMITED EFFECTS ON
PRECIPITATION.

CRAIG...TTMS (TRINIDAD AND TOBAGO)
NANDA...MDS (SURINAME)
GALVEZ...WPC (USA)