Prognostic Meteorological Discussion
Issued by NWS

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7
000
FXCA20 KWBC 281833
PMDCA

TROPICAL DISCUSSION - INTERNATIONAL DESKS
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
232 PM EDT FRI AUG 28 2015

TROPICAL STORM ERIKA WAS CENTERED AT 17.7N 69.4W...WITH MINIMUM
CENTRAL PRESSURE OF 1008 HPA...MAXIMUM SUSTAINED WINDS OF 45KT
GUSTING TO 55KT...AND WAS MOVING AT 285 DEGREES AT 16 KT. CHECK
THE NHC WEBSITE FOR UPDATES ON TRACK AND INTENSITY.

DISCUSSION FROM AUG 28/12 UTC: POTENT UPPER TROUGH OVER THE GULF
OF MEXICO IS DETACHING FROM THE WESTERLIES AND BEHAVING NOW AS A
RETROGRESSING TUTT. THE TUTT IS STILL ACCOMPANIED BY A WEAK UPPER
JET WITH A DIVERGENT ENTRANCE ENHANCING ACTIVITY OVER THE YUCATAN
PENINSULA/GULF OF CAMPECHE. THIS WILL LEAD TO MAXIMA OF
35-70MM/DAY ACROSS SOUTHERN MEXICO...AND 20-45MM/DAY IN PARTS OF
THE YUCATAN PENINSULA THROUGH EARLY SATURDAY. EFFECTS OF THE
TROUGH WILL DECREASE LATER ON AS IT STARTS RETREATING TO THE NORTH.

ACROSS MEXICO AN UPPER RIDGE CENTERS OVER THE NORTHWESTERN TIER OF
THE COUNTRY. CONVECTIVE INSTABILITY CONTINUES TO BE SEASONALLY
ENHANCED WEST OF THE SIERRA MADRE OCCIDENTAL AND INTO THE GULF OF
CALIFORNIA. TO THE EAST...HOWEVER...A VERY DRY AIR MASS CONTINUES
LEADING TO A TRANSIENT DRY SPELL ACROSS MOST OF CENTRAL AND
NORTHEASTERN MEXICO. ACTIVE CONVECTION WILL CONSTRAIN TO THE
EXTREME NORTHWEST AND SOUTHERN/SOUTHWESTERN COAST. THROUGH EARLY
SATURDAY EXPECTING MAXIMA OF 15-20MM/DAY ACROSS THE NORTHERN
SIERRA MADRE OCCIDENTAL AND ISOLATED CONVECTION OVER SINALOA.
ACROSS EXTREME SOUTHERN MEXICO INTO PUEBLA OAXACA EXPECTING
ISOLATED MAXIMA OF 20-45MM/DAY. EXPECTING A GRADUAL INCREASE IN
AMOUNTS THROUGH THE CYCLE...TO MAXIMA OF 15-30MM/DAY ACROSS THE
SIERRA MADRE OCCIDENTAL/PLAINS OF SINALOA/NAYARIT BY SUNDAY INTO
EARLY MONDAY...AND MAXIMA OF 25-50MM/DAY IN REGIONS SOUTH OF 19N.

ACROSS NORTHERN SOUTH AMERICA AND SOUTHERN CENTRAL AMERICA
ACTIVITY WILL CONTINUE CLUSTERING ALONG THE ITCZ AND MODULATED BY
WAVES IN THE TRADES. MOST ACTIVE WILL CONTINUE IN WESTERN PORTIONS
OF THE DOMAIN FROM EXTREME WESTERN VENEZUELA INTO PANAMA/COSTA
RICA. THROUGH EARLY SATURDAY EXPECTING MAXIMA OF 30-60MM/DAY
ACROSS NORTHWESTERN COLOMBIA INTO EASTERN PANAMA...AND IN PARTS OF
SOUTHERN COLOMBIA. BY SATURDAY INTO EARLY SUNDAY LARGEST AMOUNTS
ARE EXPECTED OVER NORTHWESTERN COLOMBIA INTO CENTRAL COSTA RICA
WITH MAXIMA OF 20-45MM/DAY. BY SUNDAY INTO EARLY MONDAY EXPECTING
MAXIMA OF 25-50MM/DAY OVER PANAMA AND COSTA RICA...INCLUDING THE
PACIFIC COAST OF GUANACASTE. AMOUNTS WILL ALSO INCREASE IN EL
SALVADOR/WESTERN NICARAGUA/SOUTHERN GUATEMALA TO MAXIMA OF
15-25MM/DAY. EXPECTING SIMILAR MAXIMA ACROSS EASTERN
HONDURAS/NICARAGUA IN ASSOCIATION WITH WAVE IN THE TRADE
ASSOCIATED WITH ERIKA.

THE GREATER ANTILLES ARE NOW ON THE LOOKOUT FOR ERIKA. SEE NHC
WEBSITE FOR UPDATES ON TRACK AND INTENSITY. LARGEST RAINFALL
AMOUNTS ARE EXPECTED THROUGH EARLY SATURDAY IN SOUTHERN HISPANIOLA
INCLUDING THE CITY OF SANTO DOMINGO WITH AMOUNTS OF 50-100MM/DAY
AND MAXIMA OF 150-200MM/DAY. ACROSS THE NORTHERN DOMINICAN
REPUBLIC INTO WESTERN PUERTO EXPECTING 15-20MM/DAY AND MAXIMA OF
30-60MM/DAY. BY SATURDAY INTO EARLY SUNDAY EXPECTING LARGEST
AMOUNTS ACROSS EASTERN CUBA AND THE HAITIAN PENINSULA WITH
RAINFALL IN THE ORDER OF 20-40MM/DAY AND MAXIMA OF 75-125MM/DAY.
ACROSS JAMAICA AND THE CAYMAN ISLANDS EXPECTING 15-20MM/DAY AND
MAXIMA OF 25-50MM/DAY. ACROSS THE CENTRAL BAHAMAS INTO THE TURKS
AND CAICOS/NORTHERN HAITI EXPECTING 10-15MM/DAY AND MAXIMA OF
20-40MM/DAY. BY SUNDAY INTO EARLY MONDAY LARGEST AMOUNTS ARE
EXPECTED ACROSS WESTERN CUBA WITH ACCUMULATIONS OF 15-20MM/DAY AND
MAXIMA OF 35-70MM/DAY. ACROSS THE CAYMAN ISLANDS EXPECTING MAXIMA
OF 20-35MM/DAY AND ACROSS THE NORTHWESTERN BAHAMAS EXPECTING
MAXIMA OF 15-20MM/DAY.

TROPICAL/EASTERLY WAVES INITIALIZED AT 12UTC
INITIAL  24     36     48     60     72     84     96        TYPE
40W     42W    44W    47W    50W    53W    57W    60W        TW
54W     56W    59W    63W    67W    70W    74W    78W        EW
84W     87W    90W    93W    96W    99W   101W   103W        TW
92W     96W    99W   103W   106W   109W   113W   116W        TUTT
INDCD/EW

A TROPICAL WAVE IS INITIALIZED AT 40W. THIS WAVE WILL ENTER THE
BASIN DURING MONDAY TO ENHANCE ACTIVITY ACROSS THE WINDWARD
ISLANDS DURING MONDAY INTO TUESDAY.

AN EASTERLY WAVE IS INITIALIZED AT 54W. THIS WAVE WILL ENHANCE
ACTIVITY ACROSS THE LESSER ANTILLES AS EARLY AS SATURDAY MONDAY
AND ESPECIALLY DURING THE DAY ON SATURDAY WHEN EXPECTING SCATTERED
CONVECTION AND ISOLATED MAXIMA OF 20-35MM/DAY. NOTE THAT ISOLATED
HIGHER AMOUNTS ARE POSSIBLE IN INTERACTION WITH OROGRAPHY.

TROPICAL WAVE ALONG 84W IS PRODUCING ONLY A MARGINAL ENHANCEMENT
IN CONVECTION AS IT MOVES ACROSS CENTRAL AMERICA. MOST ACTIVE IS
TO REMAIN ACROSS PANAMA AND COSTA RICA EARLY IN THE CYCLE.

TUTT-INDUCED/EASTERLY WAVE IS INITIALIZED AT 92W. THIS WAVE WILL
INITIALLY AID CONVECTIVE DEVELOPMENT IN SOUTHERN MEXICO PEAKING
DURING FRIDAY...BUT WILL THEN LIMIT ACTIVITY TO THE OPEN WATERS OF
THE EASTERN PACIFIC.

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

$$




USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.