Skip Navigation Links weather.gov 
NOAA logo - Click to go to the NOAA homepage National Weather Service   NWS logo - Click to go to the NWS homepage
The Weather Prediction Center
 
Tropical Discussion
 
(Caution: Version displayed is not the latest version. - Issued 1113Z Sep 11, 2014)
 
Version Selection
Versions back from latest:  0   1   2   3   4   5   6   7   8   9   10   
 
Abbreviations and acronyms used in this product


TROPICAL DISCUSSION - INTERNATIONAL DESKS
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
713 AM EDT THU SEP 11 2014

PRELIMINARY DISCUSSION FOR PUERTO RICO AND THE USVI. TUTT LOW AT
21N 64W ANCHORS A TROUGH THAT EXTENDS SOUTH ACROSS PUERTO
RICO/VIRGIN ISLES TO THE EASTERN CARIBBEAN. THIS REFLECTS QUITE
WELL AT 500 HPA...WITH MID LEVEL ANALYSIS SHOWING AN INVERTED
TROUGH WITH AXIS NORTH-NORTHEAST FROM THE ABC ISLES-PUERTO RICO TO
A LOW NEAR 28N 62W. THIS FAVORS A MIX OF DEEP AND SHALLOW
CONVECTION...WITH MOST ACTIVE TO THE NORTH-NORTHEAST OF THE
FORECAST AREA. AT LOW LEVELS...A TROPICAL WAVE ENTERED THE ISLAND
CHAIN EARLY THIS MORNING...WITH A DRY/DUSTY SAL TRAILING THIS
AXIS. IN INTERACTION WITH THE TUTT TO THE NORTH...THIS TRIGGERED
SCATTERED SHOWERS TO THE EAST OF THE LEEWARD ISLES. THESE FEATURES
ARE TO DOMINATE DURING THE SHORT RANGE PERIOD...WITH THE WAVE
QUICKLY MOVING ACROSS THE VIRGIN ISLES LATER THIS MORNING...AND
ACROSS PUERTO RICO LATER DURING THE DAY. WINDS ARE TO VEER TO THE
SOUTHEAST FOLLOWING WAVE PASSAGE. AS THE WAVE MOVES ACROSS THE
FORECAST AREA...EXPECTING THE SAL TO QUICKLY TAKE OVER LEADING TO
RAPID EROSION OF AVAILABLE MOISTURE. AS A RESULT...GLOBAL AND
REGIONAL MODEL GUIDANCE ONLY SHOWING WIDELY ISOLATED CONVECTION
DURING THE DAY...WITH MOST ACTIVE EXPECTED ACROSS SAINT CROIX
LATER THIS MORNING AND WESTERN INTERIOR PORTIONS OF PUERTO RICO BY
MID AFTERNOON. OVERALL...EXPECTING RAINFALL AMOUNTS OF LESS THAN A
QUARTER INCH...WITH LOCALIZED MAXIMA OF AN INCH TO LIMIT TO
WESTERN PUERTO RICO.

DURING THE SHORT TO MEDIUM RANGE PERIOD...THE TUTT LOW NORTH OF
THE ISLANDS IS TO MEANDER TO THE NORTH-NORTHWEST...NEARING 30N 70W
BY MIDDAY ON SUNDAY. ALTHOUGH THE LOW PULLS AWAY...BASE OF THE
UPPER TROUGH IS TO REMAIN ACROSS THE NORTHERN CARIBBEAN
ISLES...FAVORING AN UPPER LEVEL WESTERLY FLOW. AT MID
LEVELS...ASSOCIATED TROUGH IS TO RAPIDLY MIGRATE TO THE WEST AS A
RIDGE BUILDS FROM THE EAST. THROUGH FRIDAY EVENING/EARLY SATURDAY
MORNING THE RIDGE IS TO ESTABLISH A FOOTHOLD ACROSS THE FORECAST
AREA. THIS IS TO GRADUALLY STRENGTHEN THE TRADE WINDS CAP. THIS
WILL COMBINE WITH THE DRY SAL MOVING BEHIND THE TROPICAL WAVE TO
SUSTAIN A SHARP DECREASE IN AVAILABLE MOISTURE BY MIDDAY ON
FRIDAY. LATER DURING THE WEEKEND...AS PREVAILING EASTERLIES RETURN
TO THE FORECAST AREA...CLUSTERS OF SHALLOW MOISTURE ARE TO STREAM
ACROSS THE NORTHEAST CARIBBEAN ISLES...BUT MODELS ONLY PROJECTING
LIGHT RAINFALL AMOUNTS IN ISOLATED SHOWERS.

VALVERDE...IMN (COSTA RICA)
MEDINA...ONAMET (REPUBLICA DOMINICANA)
DAVISON...WPC (USA)