Prognostic Meteorological Discussion
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FXCA20 KWBC 171833
PMDCA

TROPICAL DISCUSSION - INTERNATIONAL DESKS
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
233 PM EDT THU APR 17 2014

DISCUSSION FROM APRIL 17/00UTC: THE LEFTOVER CONVECTIVE
INSTABILITY FROM A SURFACE FRONT EARLIER IN THE WEAK IS LINGERING
OVER THE NORTHERN BAHAMAS/FLORIDA AND CENTRAL GULF OF MEXICO. A
STRENGTHENING SHORT WAVE UPPER TROUGH IS APPROACHING THE REGION.
THE TROUGH IS FORECAST TO EXTEND ACROSS THE PLAINS OF THE USA INTO
THE NORTHWESTERN GULF BY THURSDAY EVENING. BY FRIDAY EVENING THE
TROUGH AXIS WILL EXTEND NEAR AND JUST TO THE WEST OF THE FLORIDA
PENINSULA...AND BY SATURDAY EVENING IT WILL CENTER ON A LOW OFF
THE SOUTH CAROLINA COAST WITH BASE EXTENDING INTO CENTRAL CUBA.
THIS STRENGTHENING TROUGH WILL INTERACT WITH POOL OF MOISTURE AND
TROPICAL CONVECTIVE INSTABILITY TO REFORM A SURFACE FRONT AND
PRODUCE PRECIPITATION IN ASSOCIATION. THE SURFACE FRONT WILL START
UNDULATING ACROSS THE CENTRAL GULF OF MEXICO BY THURSDAY EVENING.
BY FRIDAY EVENING FRONT WILL EXTEND ACROSS THE NORTHEASTERN GULF
AND APPROACH THE BAY OF CAMPECHE/EXTREME NORTHWESTERN YUCATAN. BY
SATURDAY EVENING IT WILL EXTEND ACROSS THE CENTRAL BAHAMAS-CENTRAL
CUBA INTO NORTHERN YUCATAN WHILE WEAKENING. A SHEAR LINE WILL ALSO
DEVELOP DURING SATURDAY. BY SATURDAY EVENING IT WILL EXTEND INTO
NORTHEASTERN HONDURAS WHERE IT WILL MEANDER WHILE WEAKENING DURING
SUNDAY. EXPECTING ENHANCED CONVECTION WITH THIS SYSTEM.

DURING THURSDAY INTO FRIDAY...PRE-FRONTAL CONVECTIVE INSTABILITY
WILL INTERACT WITH THE DIURNAL CYCLE OF RADIATION AND CONVECTIVE
INSTABILITY IN THE BASE OF UPPER TROUGH. THIS IS TO PRODUCE
SHOWERS AND THUNDERSTORMS ACROSS CENTRAL AND EASTERN MEXICO WITH
ACCUMULATIONS OF 05-10MM/DAY AND MAXIMA OF 15-25MM. EXPECTING
SHOWERS AND ISOLATED THUNDERSTORMS ACROSS THE BAHAMAS TO PRODUCE
05-10MM/DAY AND MAXIMA OF 15MM. DURING FRIDAY INTO
SATURDAY...EXPECTING WIDESPREAD ACTIVITY ACROSS EASTERN AND
SOUTHERN MEXICO. OVER THE CENTRAL AND EASTERN MOUNTAINS EXPECTING
10-15MM/DAY AND MAXIMA OF 20-30MM. ACROSS YUCATAN/GUATEMALA INTO
CHIAPAS EXPECTING SIMILAR AMOUNTS. FRONTAL-PRE-FRONTAL CONVECTION
WILL ALSO AFFECT NORTHWESTERN CUBA PRODUCING AMOUNTS OF
05-10MM/DAY AND MAXIMA OF 15MM. DURING SATURDAY INTO EARLY SUNDAY
FRONT WILL START TO WEAKEN...YET ENHANCED ACTIVITY IS STILL
EXPECTED. ACROSS CHIAPAS/SOUTHERN YUCATAN INTO GUATEMALA/NORTHERN
HONDURAS/BELIZE EXPECTING ACCUMULATIONS OF 05-10MM/DAY AND MAXIMA
OF 15-20MM. ACROSS CUBA...EXPECTING PROGRESSIVE
FRONTAL/PRE-FRONTAL CONVECTION TO PRODUCE MAXIMA OF 15-25MM.
ACROSS THE NORTHERN BAHAMAS EXPECTING ISOLATED MAXIMA OF 20-35MM.

ACROSS THE EASTERN CARIBBEAN...RELATIVELY QUIET PATTERN WILL
CONTINUE WITH MOST ACTIVITY IN THE FORM OF LIGHT TO MODERATE TRADE
WIND SHOWERS. A LARGE TUTT WILL CONTINUE MEANDERING ACROSS THE
NORTH ATLANTIC TO THE EAST OF 55W...WHILE A MID/UPPER RIDGE
MEANDERS ACROSS THE CENTRAL CARIBBEAN. THE RIDGE IS FORECAST TO
SLOWLY EXPAND TO THE EAST...SUSTAINING SUBSIDENCE INVERSION ACROSS
THE REGION. EXPECTING MOST ACTIVE/PERSISTENT SHOWERS TO AFFECT THE
NORTHEASTERN ANTILLES TODAY...WITH A DECREASING TREND IN
ACCUMULATIONS AFTERWARDS. TODAY...EXPECTING AMOUNTS OF 05-10MM/DAY
AND MAXIMA OF 15-20MM EXTENDING FROM THE FRENCH ANTILLES
NORTHWESTWARD INTO PUERTO RICO/USVI.

ACROSS NORTHERN SOUTH AMERICA...SEASONAL CONVECTION IS ACTIVATING
ONCE AGAIN ACROSS COLOMBIA AND PARTS OF VENEZUELA. ACTIVITY WILL
BE MODULATED BY A BROAD WEAK WAVE IN THE TRADES. THE WAVE HAS A
WEAK SIGNATURE IN THE WIND FIELD BUT IS ASSOCIATED WITH A REGION
OF HIGH CONVECTIVE INSTABILITY. FURTHERMORE ACTIVITY WILL BE
ENHANCED BY FAVORABLE UPPER DIVERGENT PATTERN IN THE PERIPHERY OF
MID-UPPER RIDGE...AND DIVERGENT MJO CONDITIONS BECOMING MORE
PROMINENT IN COMING DAYS. WAVE WILL ENHANCE ACTIVITY IN MOST OF
ANDEAN COLOMBIA ON DAY 01 PRODUCING AMOUNTS OF 10-15MM/DAY AND
MAXIMA OF 20-40MM. ON DAY 02 STRONGEST ACTIVITY WILL CONCENTRATE
ACROSS MOST OF ANDEAN COLOMBIA INTO THE PACIFIC BASIN WITH
ACCUMULATIONS OF 15-20MM/DAY AND MAXIMA OF 25-50MM. ON DAY 03
EXPECTING A SIMILAR DISTRIBUTION WITH MAXIMA INCREASING TO
35-70MM. EXPECTING ALSO AN ACTIVATION ACROSS PANAMA ON DAYS 03/04.

TROPICAL/EASTERLY WAVES INITIALIZED AT 12UTC
INITIAL   24    36    48    60    72    84    96   TYPE
NONE SIGNIFICANT

GALVEZ...WPC (USA)
GARCIA...SMN (MEXICO)
FIGUEROA...MARN (EL SALVADOR)
$$




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