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
 
(Latest Discussion - Issued 1824Z Sep 17, 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
224 PM EDT WED SEP 17 2014

AT 15 UTC TS ODILE CENTERED NEAR 30.6N 113.3W...WITH MAXIMUM
SUSTAINED WINDS OF 35KT AND CENTRAL PRESSURE OF 997 HPA...MOVING
TO THE NORTHEAST AT 5KT.

AT 15 UTC TS POLO CENTERED NEAR 15.7N 102.4W...WITH MAXIMUM
SUSTAINED WINDS OF 50KT AND CENTRAL PRESSURE OF 998 HPA...MOVING
TO THE NORTHWEST AT 9KT.

DISCUSSION FROM SEPTEMBER 17/00UTC: UPPER PATTERN OVER WESTERN
PORTIONS OF THE DOMAIN REMAINS UNDER INFLUENCE OF A MID/UPPER
LEVEL RIDGE. THIS RIDGE ANCHORS AT 250 HPA ON A CLOSED HIGH OVER
CHIHUAHUA/SONORA IN NORTHERN MEXICO...AND SPANS FROM CENTRAL
MEXICO TO THE WESTERN USA. THE RIDGE IS VENTING CONVECTION IN
ASSOCIATION WITH TS ODILE. THE NHC FORECASTS THIS STORM TO LIFT
ACROSS NORTHERN SONORA INTO SOUTHERN ARIZONA THROUGH THURSDAY
MORNING...WHERE IT IS TO QUICKLY WEAKEN. MEANWHILE...IT IS TO
SUSTAIN ORGANIZED CONVECTION ACROSS NORTHWEST MEXICO WITH
ACCUMULATION OF 25-50MM/DAY AND MAXIMA OF 75-100MM.

THE RIDGE IS TO ALSO PROVIDE THE VENTILATION ALOFT AND STEERING
FLOW TO TS POLO. PER THE NHC FORECAST...THE STORM IS TO CONTINUE
TO THE NORTHWEST WHILE REMAINING OFF THE SOUTHWEST COAST OF
MEXICO. THROUGH THURSDAY MORNING... HOWEVER...IT IS TO STRENGTHEN
TO A HURRICANE. CONVECTION ON ITS OUTER BANDS IS TO AFFECT THE
SOUTHWEST COAST OF MEXICO BETWEEN JALISCO AND GUERRERO... WITH
RAINFALL AMOUNTS OF 25-50MM/DAY AND MAXIMA OF 75-150MM. THROUGH
THURSDAY EVENING/EARLY FRIDAY MORNING CONVECTION IS TO THEN BUILD
NORTH INTO SOUTHERN SINALOA. THIS IS TO ADVECT MOISTURE INLAND
ACROSS THE CENTRAL STATES OF MEXICO...TO FEED DIURNAL
CONVECTION...WITH RAINFALL AMOUNTS OF 15-20MM/DAY AND MAXIMA OF
30-60MM. AS THE STORM MOVES AWAY...THIS WILL DECREASE TO MAXIMA OF
20-35MM LATER ON THURSDAY TO FRIDAY. THE STORM IS TO ALSO MODULATE
THE ITCZ NORTH ALONG THE SOUTH COAST OF MEXICO TO SOUTHERN
GUATEMALA-EL SALVADOR. INITIALLY EXPECTING ACCUMULATION OF
10-15MM/DAY AND MAXIMA OF 20-35MM. THROUGH FRIDAY EVENING...AS THE
STORM MOVES AWAY...THIS INCREASES TO 15-20MM/DAY AND MAXIMA OF
30-60MM.

DOWNSTREAM FROM THE CONTINENTAL RIDGE...A POLAR TROUGH EXTENDS
SOUTH ACROSS THE EASTERN USA TO THE FLORIDA PENINSULA. THE TROUGH
IS TO REACH MAXIMUM AMPLITUDE EARLY IN THE CYCLE. THE ASSOCIATED
FRONT CONFINES TO THE SOUTHEAST USA/NORTHERN GULF OF
MEXICO...WHILE SUSTAINING AN INDUCED PREFRONTAL TROUGH ACROSS THE
NORTHWEST BAHAMAS. THIS IS TO ENHANCE MOISTURE CONVERGENCE WHILE
FAVORING DEEP LAYER CONVECTIVE INSTABILITY...WITH POTENTIAL FOR
STRONG CONVECTION AS MID LEVEL VORTICES ROUND THE BASE OF THE LONG
WAVE TROUGH. ACROSS THE NORTHWEST BAHAMAS INITIALLY EXPECTING
RAINFALL AMOUNTS OF 10-15MM/DAY AND MAXIMA OF 20-35MM/DAY. THROUGH
FRIDAY EVENING EXPECTING AN INCREASE WITH ACCUMULATION OF 15-20MM
AND MAXIMA OF 25-50MM.

A TUTT LOW SOUTH OF THE CAYMAN ISLES EXTENDS A SHORT WAVE TROUGH
ACROSS EASTERN HONDURAS/NICARAGUA. THIS TROUGH IS CUT OFF FROM THE
FLOW...AND AS SUCH IS TO GRADUALLY WEAKEN AS THE CYCLE PROGRESSES.
REMNANTS OF THIS VORTEX WILL SLOWLY LIFT ACROSS THE CAYMAN ISLES
TO WESTERN CUBA LATER THIS WEEK. EARLY IN THE CYCLE THE TROUGH
ALOFT IS TO INTERACT WITH THE ITCZ AS IT MEANDERS OVER SOUTHERN
NICARAGUA/COSTA RICA BORDER TO THE SOUTHERN CARIBBEAN...TO FAVOR
RAINFALL AMOUNTS OF 15-20MM/DAY AND MAXIMA OF 25-50MM. BUT AS THE
TUTT WEAKENS...CONVECTION ACROSS EASTERN NICARAGUA DECREASES TO
05-10MM/DAY AND MAXIMA OF 15-25MM...WHILE OVER SOUTHERN NICARAGUA
TO COSTA RICA MAXIMA IS TO PEAK AT 30-60MM ALONG THE ITCZ. ACROSS
THE CAYMAN ISLES THIS IS TO FAVOR ISOLATED TO SCATTERED CONVECTION
OVER THE NEXT FEW DAYS...WHILE OVER WESTERN CUBA MOST ACTIVE IS
EXPECTED LATER ON FRIDAY... WHEN IT IS TO FAVOR RAINFALL AMOUNTS
OF 15-20MM/DAY AND MAXIMA OF 25-50MM.

ANOTHER TUTT EXTENDS ACROSS THE NORTHEAST CARIBBEAN ISLES...WITH
BASE OF THE TROUGH GRAZING PORTIONS OF HISPANIOLA/PUERTO RICO.
UNDER INFLUENCE OF A 50-60KT JET MAXIMA TO THE EAST...TROUGH IS TO
SLOWLY PULL ACROSS PUERTO RICO LATER THIS AFTERNOON...NEARING THE
ISLAND CHAIN LATER ON THURSDAY. AS THE SUBEQUATORIAL RIDGE
MEANDERS TO THE SOUTH...THE TROUGH IS TO THEN BECOME NARROW AN
ELONGATED AS IT IS TO STRETCH ALONG ITS EASTERN FRINGES OF THE
RIDGE TO THE ORINOCO DELTA REGION IN VENEZUELA. AT MID LEVELS...A
RIDGE EXTENDS TO THE SOUTHWEST ACROSS THE LEEWARD ISLES/PUERTO
RICO TO THE EASTERN CARIBBEAN. MID LEVEL RIDGE IS TO SLOWLY LIFT
NORTH OF THE LEEWARD ISLES/PUERTO RICO LATER ON THURSDAY. AS IT
PULLS AWAY...MID LEVEL CAP INVERSION OVER THE NORTHEAST CARIBBEAN
IS TO WEAKEN. THROUGH FRIDAY ENVIRONMENTAL CONDITIONS ARE FORECAST
TO BECOME MORE FAVORABLE AND CONDUCIVE TO DEEP CONVECTION AS A
SHORT WAVE TROUGH APPROACHES FROM THE EAST. THIS WILL COMBINE WITH
TROPICAL WAVE ENTERING THE BASIN TO FAVOR ORGANIZED CONVECTION
(SEE BELOW FOR DETAILS). OTHER ENHANCEMENT IS EXPECTED TO THE
SOUTH ALONG THE NEAR EQUATORIAL TROUGH AS IT MEANDERS OVER
NORTHEAST VENEZUELA TO THE SOUTHERN WINDWARD ISLES...WERE WE
EXPECT RAINFALL AMOUNTS OF 05-10MM/DAY AND MAXIMA OF 15-20MM.

TROPICAL/EASTERLY WAVES INITIALIZED AT 12UTC
INITIAL  24     36     48     60     72     84     96     TYPE
36W     41W    44W    47W    49W    51W    54W    57W     TW
58W     60W    63W    66W    68W    71W    73W    76W     TW

TROPICAL WAVE ALONG 36W MOVES NORTH OF THE GUIANAS LATER ON
FRIDAY/EARLY SATURDAY MORNING...WITH MOST ACTIVE CONVECTION
EXPECTED ALONG AND NORTH OF THE ITCZ TO THE NORTH.

TROPICAL WAVE ALONG 58W MOVES ACROSS THE LESSER ANTILLES LATER ON
WEDNESDAY... WHERE IT IS TO SUSTAIN RAINFALL AMOUNTS OF
05-10MM/DAY AND MAXIMA OF 15-25MM. THROUGH MID MORNING ON THURSDAY
IT PULLS ACROSS THE VIRGIN ISLES TO PUERTO RICO. THIS IS TO THEN
FAVOR RAINFALL AMOUNTS OF 10-15MM/DAY AND MAXIMA OF 20-45MM. DEEP
TROPICAL MOISTURE IS TO FOLLOW THIS WAVE...WITH AN ITCZ MOIST
PLUME TO LIFT ACROSS THE FRENCH ISLES TO PUERTO RICO AND THE
VIRGIN ISLES. THIS IS TO RESULT IN ADDITIONAL CONVECTION WITH
ACCUMULATION OF 10-15MM/DAY AND MAXIMA OF 20-35MM. SIMILAR AMOUNTS
ARE THEN EXPECTED ACROSS THE DOMINICAN REPUBLIC ON FRIDAY TO
SATURDAY. ACROSS CENTRAL VENEZUELA...IN INTERACTION WITH THE
NET...EXPECT RAINFALL AMOUNTS OF 05-10MM/DAY AND MAXIMA OF
15-25MM. OVER NORTHWEST VENEZUELA TO NORTHERN COLOMBIA THIS
INCREASE TO 10-15MM/DAY AND MAXIMA OF 20-40MM.

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