[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 220600
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
205 AM EDT MON AUG 22 2011

TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL
AMERICA...GULF OF MEXICO...CARIBBEAN SEA...NORTHERN SECTIONS OF
SOUTH AMERICA...AND ATLANTIC OCEAN TO THE AFRICAN COAST FROM THE
EQUATOR TO 32N. THE FOLLOWING INFORMATION IS BASED ON SATELLITE
IMAGERY...WEATHER OBSERVATIONS...RADAR...AND METEOROLOGICAL
ANALYSIS.

BASED ON 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
0545 UTC.

...SPECIAL FEATURES...
TROPICAL STORM IRENE NEAR 18.0N 65.7W AT 0500 UTC AUG 22 OR
ABOUT 35 MI...55 KM SE OF SAN JUAN PUERTO RICO. IRENE IS MOVING
MOVING WNW AT 13 KT. MINIMUM CENTRAL PRESSURE IS 989 MB. MAXIMUM
SUSTAINED WIND SPEED IS 60 KT WITH GUSTS 75 KT. PLEASE SEE THE
LATEST INTERMEDIATE PUBLIC ADVISORY UNDER AWIPS/WMO HEADER
MIATCPAT4/ WTNT34 KNHC AND THE FULL FORECAST/ADVISORY UNDER
AWIPS/WMO HEADER MIATCMAT4/WTNT24 KNHC FOR MORE DETAILS.
SCATTERED STRONG CONVECTION IS OVER PUERTO RICO AND SURROUNDING
WATERS FROM 17N-23N BETWEEN 62W-68W. SOME STRENGTHENING IS STILL
POSSIBLE THIS MORNING...AND IRENE COULD BECOME A HURRICANE
BEFORE MOVING OVER PUERTO RICO IN THE NEXT COUPLE OF HOURS.
IRENE IS EXPECTED TO PRODUCE TOTAL RAINFALL ACCUMULATIONS OF 5
TO 10 INCHES ACROSS PUERTO RICO...THE VIRGIN ISLANDS...THE
DOMINICAN REPUBLIC...HAITI...THE SOUTHEASTERN BAHAMAS AND THE
TURKS AND CAICOS ISLANDS.  ISOLATED MAXIMUM AMOUNTS OF UP TO 20
INCHES ARE POSSIBLE.  THESE RAINS COULD CAUSE LIFE-THREATENING
FLASH FLOODS AND MUD SLIDES IN AREAS OF STEEP TERRAIN. SOME
WEAKENING IS EXPECTED THIS AFTERNOON AND TONIGHT AS THE CENTER
MOVES NEAR OR OVER THE DOMINICAN REPUBLIC. SOME RESTRENGTHENING
IS EXPECTED LATE TUESDAY AFTER THE CENTER MOVES BACK OVER WATER.

TROPICAL DEPRESSION HARVEY NEAR 19.0N 95.9W AT 0500 UTC AUG 22
OR ABOUT 20 MI...35 KM ESE OF VERACRUZ MEXICO. HARVEY IS MOVING
WNW AT 10 KT. MINIMUM CENTRAL PRESSURE IS 1005 MB. MAXIMUM
SUSTAINED WIND SPEED IS 30 KT GUSTS 40 KT. PLEASE SEE THE LATEST
INTERMEDIATE PUBLIC ADVISORY UNDER AWIPS/WMO HEADER
MIATCPAT3/WTNT33 KNHC AND THE FULL FORECAST/ADVISORY UNDER
AWIPS/WMO HEADER MIATCMAT3/ WTNT23 KNHC FOR MORE DETAILS.
SCATTERED MODERATE TO STRONG CONVECTION IS OVER SOUTHERN MEXICO
AND THE BAY OF CAMPECHE S OF 22N E OF 90W. HARVEY IS EXPECTED TO
PRODUCE ADDITIONAL RAINFALL ACCUMULATIONS OF 2 TO 4 INCHES OVER
PORTIONS OF THE MEXICAN STATES OF VERACRUZ...OAXACA...HIDALGO
...PUEBLA...AND TIAXCALA...WITH ISOLATED MAXIMUM STORM TOTAL
AMOUNTS OF 10 INCHES. THESE RAINS COULD PRODUCE LIFE-THREATENING
FLASH FLOODS AND MUD SLIDES...ESPECIALLY IN AREAS OF STEEP
TERRAIN. THE DEPRESSION IS FORECAST TO DISSIPATE BY MONDAY NIGHT.

...THE ITCZ/THE MONSOON TROUGH...

A 1011 MB LOW IS EMBEDDED IN THE MONSOON TROUGH NEAR 19N30W.
THIS LOW IS FORECAST TO MOVE NW OVER COOLER WATERS TO THE
CENTRAL ATLANTIC OVER THE NEXT SEVERAL DAYS. HOWEVER...AS THE
SYSTEM TRACKS NW IT WILL BUILD A TIGHT PRESSURE GRADIENT BETWEEN
THE BROAD RIDGE AND THE SURFACE LOW THAT COULD GENERATE GUSTY
WINDS TO NEAR GALE FORCE CRITERIA DURING THE FORECAST PERIOD.
THE FLOW AROUND THE EAST SIDE OF THE LOW HAS BECOME THE DOMINANT
FEATURE IN THE AREA. THIS HAS CAUSED THE THE MONSOON TROUGH TO
SPLIT BETWEEN THE LOW AND THE AFRICAN COAST. DUE TO THE BROAD
CYCLONIC WIND FIELD ASSOCIATED TO T.S. IRENE IN THE SPECIAL
FEATURES AND THE MONSOON TROUGH...THERE IS NO CONVERGENCE OF NE
AND SE TRADE WINDS...THUS THERE IS NO ITCZ DEPICTED ON THE
SURFACE ANALYSIS. THE MONSOON TROUGH IS ANALYZED FROM THE LOW
PRESSURE SYSTEM NEAR 19N30W SSW ALONG 12N32W TO 8N40W..THEN W TO
NEAR 9N51W. SCATTERED MODERATE TO ISOLATED STRONG CONVECTION IS
WITHIN 120 NM ON EITHER SIDE OF THE MONSOON TROUGH AND THE LOW.
SIMILAR CONVECTION IS MOVING OFF THE AFRICAN COAST OF
GUINEA...GUINEA-BISSAU...THE GAMBIA...AND SENEGAL FROM 9N-15N
ASSOCIATED TO A SURFACE LOW ALONG THE MONSOON TROUGH INLAND OVER
SENEGAL NEAR 15N13W. THIS LOW WILL BE CLOSELY MONITORED FOR
FUTURE DEVELOPMENT AS IT MOVES OFFSHORE OVERNIGHT MON NIGHT.

...DISCUSSION...

GULF OF MEXICO...
THE MAIN CONCERN OVER THE GULF TONIGHT IS T.D. HARVEY MOVING
ACROSS THE WARM WATERS OF THE BAY OF CAMPECHE HEADING TOWARD THE
COAST OF VERACRUZ MEXICO. FOR MORE INFORMATION SEE SPECIAL
FEATURES ABOVE. ELSEWHERE ACROSS THE DISCUSSION AREA...UPPER
LEVEL EASTERLY FLOW COVERS THE GULF...ON THE SOUTH SIDE OF THE
BROAD UPPER OMEGA RIDGE SETTLED ACROSS THE CONUS. HOWEVER...A
WEAK SURFACE TROUGH IS ANALYZED FROM 29N86W TO 25N89W. OTHER
THAN A SLIGHT CYCLONIC CURVATURE ALONG THE AXIS...NO CONVECTION
IS OBSERVED. THIS TROUGH WILL GRADUALLY DIMINISH THROUGH MONDAY.
WIDELY SCATTERED SHOWERS ARE OVER THE SE BASIN INCLUDING THE
STRAITS OF FLORIDA S OF 26N E OF 84W. HARVEY IS FORECAST TO
BRIEFLY BECOME A MINIMAL TROPICAL STORM BEFORE MAKING LANDFALL
MON MORNING AND THEN DIMINISH TO A REMNANT LOW OVER CENTRAL
MEXICO BY EARLY TUE.

CARIBBEAN SEA...
THE PRIMARY CONCERN THIS MORNING IS T.S. IRENE MOVING OVER THE
ISLAND OF PUERTO RICO. FOR MORE INFORMATION SEE SPECIAL FEATURES
ABOVE. OTHERWISE...WIDELY SCATTERED SHOWERS AND ISOLATED
THUNDERSTORMS REMAIN OVER THE WRN AND NW BASIN W OF 78W. THE
ACTIVITY IN THE SW IS DUE TO THE MONSOON TROUGH EXTENDING INLAND
ACROSS COSTA RICA TO NORTHERN COLOMBIA. THE REMAINDER OF THE
CARIBBEAN IS UNDER MOSTLY CLEAR SKIES WITH A FEW ISOLATED
SHOWERS EMBEDDED IN THE 5-15 KT EASTERLY TRADE WIND FLOW.
TROPICAL STORM CONDITIONS ARE EXPECTED TO DIMINISH IN THE
CARIBBEAN LATE MON OR EARLY TUE AS IRENE TRACKS THROUGH THE
NORTHERN PORTION OF HISPANIOLA AND INTO THE SW NORTH ATLANTIC.

ATLANTIC OCEAN...
THE PRIMARY CONCERN THIS EVENING IS T.S. IRENE MOVING OVER THE
ISLAND OF PUERTO RICO. SYMMETRIC CONVECTIVE OUTFLOW FROM IRENE
IS NOTICED ON SATELLITE INFRA RED IMAGERY EXTENDING INTO THE
ATLANTIC TO NEAR 500 NM NE OF THE CENTER. SEE SPECIAL FEATURES
ABOVE FOR MORE INFORMATION ON IRENE. OTHERWISE...THE REMAINDER
OF THE ATLC BASIN IS DOMINATED BY A BROAD SURFACE RIDGE ANCHORED
BY A 1027 MB HIGH W OF THE AZORES NEAR 37N33W...LEAVING THE
REMAINDER OF THE DISCUSSION AREA UNDER FAIR CONDITIONS THIS
EVENING. SOUTH OF THE RIDGE LIES A LOW PRES CENTER NEAR 19N30W
ASSOCIATED WITH THE MONSOON TROUGH. THIS LOW IS EMBEDDED IN DRY
AIR AND AFRICAN DUST THAT IS INHIBITING DEEP CONVECTION. THIS
LOW IS FORECAST TO MOVE NW OVER COOLER WATERS TO THE CENTRAL
ATLANTIC OVER THE NEXT SEVERAL DAYS. THE MOST RECENT FORECAST
CARRIES IRENE INTO THE EASTERN DOMINICAN REPUBLIC BEFORE PASSING
OVER THE NORTH PORTION OF HISPANIOLA ON MONDAY AND BETWEEN
EASTERN CUBA AND GREAT INAGUA ISLAND BY TUESDAY EVENING.

FOR ADDITIONAL INFORMATION PLEASE VISIT
HTTP://WWW.HURRICANES.GOV/MARINE

$$

GARCIA


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