[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 212321
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT SUN JUL 21 2013

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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
2245 UTC.

...TROPICAL WAVES...
TROPICAL WAVE WAS INTRODUCED ON THE 1800 UTC MAP JUST INLAND
ALONG THE COAST OF AFRICA FROM 18N16W TO 10N14W. A SURGE OF DEEP
MOISTURE IS EXPANDING ALONG THE COAST OF W AFRICA FROM SIERRA
LEONE TO MAURITANIA AS DEPICTED IN TOTAL PRECIPITABLE WATER
IMAGERY. CLUSTERS OF SCATTERED MODERATE/STRONG CONVECTION ARE
FROM 8N-12N BETWEEN 15W-18W.

TROPICAL WAVE EXTENDS FROM 22N53W TO 13N58W MOVING W-NW NEAR 15
KT. WAVE IS EMBEDDED WITHIN A HIGH AMPLITUDE SURGE OF DEEP
MOISTURE AS DEPICTED IN TOTAL PRECIPITABLE WATER IMAGERY. WAVE
IS WELL DEFINED ON SATELLITE IMAGERY.SCATTERED SHOWERS/ISOLATED
THUNDERSTORMS ARE FROM 19N-20N BETWEEN 53W-56W WITH SCATTERED
SHOWERS AND POSSIBLE ISOLATED THUNDERSTORMS FROM 15N-20N BETWEEN
THE WAVE AND 60W.

...ITCZ/MONSOON TROUGH...
THE MONSOON TROUGH EXTENDS ACROSS AFRICA INTO THE E TROPICAL
ATLC NEAR 13N17W AND CONTINUES TO 9N28W WHERE THE ITCZ BEGINS
AND CONTINUES ALONG 7N36W 3N45W TO SOUTH AMERICA NEAR 3N51W.
SCATTERED STRONG CONVECTION IS FROM 7N-9N BETWEEN 28W-30W.
SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS WITHIN 90/120
NM EITHER SIDE OF THE MONSOON TROUGH/ITCZ BETWEEN 26W-31W.
SCATTERED MODERATE WITH EMBEDDED CLUSTERS OF ISOLATED STRONG
CONVECTION IS WITHIN 120 NM EITHER SIDE OF THE MONSOON TROUGH
BETWEEN 21W-26W.

...DISCUSSION...

GULF OF MEXICO...
AN UPPER TROUGH EXTENDS FROM OVER MISSISSIPPI INTO THE NW GULF TO
26N93W GENERATING SCATTERED SHOWERS/ISOLATED THUNDERSTORMS N OF
27N TO OVER THE N GULF COAST BETWEEN 87W-96W. AN UPPER RIDGE
COVERS THE E GULF ANCHORED NEAR 28N84W AND IS PROVIDING
DIFFLUENCE ALOFT TO GENERATE SCATTERED SHOWERS/ISOLATED
THUNDERSTORMS INLAND OVER THE FLORIDA PENINSULA. AN UPPER RIDGE
INLAND OVER MEXICO IS PROVIDING DIFFLUENCE ALOFT TO GENERATE
SCATTERED SHOWERS AND POSSIBLE ISOLATED THUNDERSTORMS WITHIN 120
NM ALONG THE COAST BETWEEN 20N-24N. OTHERWISE A SURFACE RIDGE
EXTENDS FROM THE W ATLC ACROSS CENTRAL FLORIDA TO THE TEXAS
COAST NEAR CORPUS CHRISTI. SURFACE RIDGE WILL REMAIN ALONG 28N
THROUGH MON THEN FROM SW FLORIDA TO NE TEXAS TUE THROUGH FRI.

CARIBBEAN SEA...
AN UPPER RIDGE OVER THE E GULF OF MEXICO COVERS THE NW CARIBBEAN
N OF 17N W OF 79W WHILE A SECOND UPPER RIDGE ANCHORED IN THE
TROPICAL ATLC COVERS THE CARIBBEAN E OF 77W. THE UPPER TROUGH
OVER THE W ATLC DIPS S OVER PORTIONS OF HAITI AND E CUBA TO
JAMAICA LEAVING AN INVERTED UPPER TROUGH COVERING THE REMAINDER
OF THE SW CARIBBEAN. THE MONSOON TROUGH EXTENDS FROM COLOMBIA
NEAR 10N75W ACROSS PANAMA/COSTA RICA NEAR 9N82W GENERATING
SCATTERED SHOWERS/ISOLATED THUNDERSTORMS S OF 13N W OF 77W. THE
EASTERLY TRADE WINDS ARE GENERATING ISOLATED SHOWERS AND
POSSIBLE ISOLATED THUNDERSTORMS OVER THE E CARIBBEAN FROM 12N-
17N E OF 70W ACROSS THE LESSER ANTILLES LEAVING THE REMAINDER OF
THE CARIBBEAN WITH MOSTLY CLEAR SKIES THIS EVENING. THE TROPICAL
WAVE WILL ENTER THE E CARIBBEAN LATE TONIGHT PASSING THROUGH THE
CENTRAL CARIBBEAN MON NIGHT AND TUE THEN WILL WEAKEN OVER THE W
CARIBBEAN WED AND THU. OTHERWISE FRESH TO STRONG EASTERLY TRADE
WINDS OVER THE S CENTRAL CARIBBEAN WILL PERSIST THROUGH TUE THEN
FRESH TRADES EXPECTED WED THROUGH FRI.

HISPANIOLA...
ISOLATED SHOWERS DOT HISPANIOLA THIS EVENING AND WILL CONTINUE
INTO TONIGHT. THE UPPER TROUGH OVER W HAITI WILL REMAIN THROUGH
MID WEEK. THE TROPICAL WAVE WILL MOVE ACROSS THE CARIBBEAN S OF
HISPANIOLA LATE MON AND TUE INCREASING THE CHANCES OF HEAVY
PRECIPITATION.

ATLANTIC OCEAN...
AN UPPER TROUGH COVERS THE W ATLC WITH THE AXIS EXTENDING THROUGH
32N68W ALONG 26N70W TO ACROSS E CUBA INTO THE N/CENTRAL
CARIBBEAN GENERATING SCATTERED SHOWERS/ISOLATED THUNDERSTORMS N
OF 27N BETWEEN 69W-73W AND WITHIN 60 NM ALONG THE COAST OF
FLORIDA AND GEORGIA. SCATTERED SHOWERS AND POSSIBLE ISOLATED
THUNDERSTORMS ARE OVER THE N BAHAMA ISLANDS FROM 25N-28N BETWEEN
75W-79W. AN UPPER LOW IS IN THE CENTRAL ATLC CENTERED NEAR
28N49W GENERATING SCATTERED SHOWERS/ISOLATED THUNDERSTORMS FROM
24N27N BETWEEN 47W-51W. OTHERWISE...A SURFACE RIDGE DOMINATES
THE ATLC AND EXTENDS W OVER THE GULF OF MEXICO ANCHORED BY A
1023 HIGH IN THE W ATLC NEAR 29N64W...A 1023 MB HIGH IN THE
CENTRAL ATLC NEAR 32N47W...AND A WEAK 1021 MB HIGH IN THE E ATLC
NEAR 32N25W. AN UPPER TROUGH OVER THE NE ATLC IS SUPPORTING A
WEAK 1019 MB LOW NEAR 33N32W WITH A SURFACE TROUGH EXTENDING SE
ALONG 31N33W TO 29N38W. ISOLATED SHOWERS ARE POSSIBLE WITHIN 60
NM OF THE SURFACE TROUGH. THE NOAA GOES-R SATELLITE IMAGERY
SHOWS SAHARAN AIR LAYER COVERING THE TROPICAL ATLC WITHIN
350/400 NM OF LINE FROM 13N54W ALONG 21N30W TO BEYOND 32N15W.
SURFACE RIDGE WILL MEANDER FROM BERMUDA TO SE FLORIDA THROUGH
FRI.

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

$$
PAW


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