Tropical Weather Discussion
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000
AXNT20 KNHC 041037
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 AM EDT SAT JUL 04 2015

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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1015 UTC.

...SPECIAL FEATURES...

...GALE IN THE CARIBBEAN...
A GALE WARNING IS IN EFFECT FOR THE SW CARIBBEAN FROM 11N-13.5N
BETWEEN 74W-77W THROUGH MON MORNING. THESE WINDS ARE GENERATED
BY A TIGHT PRESSURE GRADIENT BETWEEN THE STRONG SURFACE RIDGE
OVER THE ATLC AND THE LOWER PRESSURE OVER SOUTH AMERICA. SEE
LATEST NWS HIGH SEAS FORECAST UNDER AWIPS/WMO HEADERS
MIAHSFAT2/FZNT02 KNHC FOR MORE DETAILS.

...TROPICAL WAVES...

TROPICAL WAVE IN THE E TROPICAL ATLC EXTENDS ALONG 28W FROM 6N-
16N MOVING W AT 10-15 KT OVER THE PAST 24 HOURS. THE TOTAL
PRECIPITABLE WATER IMAGERY SHOWS THE WAVE IS EMBEDDED WITHIN AN
SURGE OF MODERATE MOISTURE. NO ASSOCIATED DEEP CONVECTION.

TROPICAL WAVE IN THE CENTRAL TROPICAL ATLC EXTENDS ALONG 43W
FROM 5N-12N MOVING AT 5-10 KT OVER THE PAST 24 HOURS. THE TOTAL
PRECIPITABLE WATER IMAGERY SHOWS THE WAVE IS EMBEDDED WITHIN LOW
AMPLITUDE SURGE OF DEEP MOISTURE. NO ASSOCIATED DEEP CONVECTION.

TROPICAL WAVE IN THE CENTRAL CARIBBEAN EXTENDS ALONG 71W/72W
FROM 18N TO THE COAST OF VENEZUELA MOVING W AT 20-25 KT OVER THE
PAST 24 HOURS. THE TOTAL PRECIPITABLE WATER IMAGERY SHOWS THE
WAVE IS EMBEDDED WITHIN A SURGE OF MODERATE MOISTURE. NO
ASSOCIATED DEEP CONVECTION.

...ITCZ/MONSOON TROUGH...

THE MONSOON TROUGH EXTENDS ACROSS AFRICA INTO THE TROPICAL ATLC
NEAR 14N16W TO 9N20W WHERE THE ITCZ BEGINS AND CONTINUES TO E OF
THE TROPICAL WAVE NEAR 9N27W THEN RESUMES W OF THE WAVE NEAR
9N30W TO E OF THE NEXT TROPICAL WAVE NEAR 8N42W THEN RESUMES W
OF THIS WAVE NEAR 8N45W INTO SOUTH AMERICA NEAR 6N58W. SMALL
CLUSTERS OF ISOLATED MODERATE CONVECTION ARE FROM 7N-8N BETWEEN
17W-22W AND WITHIN 30 NM OF 10N BETWEEN 34W-38W.

...DISCUSSION...

GULF OF MEXICO...
AN UPPER TROUGH DOMINATES THE GULF THIS MONRING EXTENDING FROM
NEAR CEDAR KEY FLORIDA THROUGH AN UPPER LOW NEAR 26N87W AND A
SECOND UPPER LOW NEAR 23N89W TO CIUDAD DEL CARMEN MEXICO. A
SURFACE TROUGH AT 04/0900 UTC EXTENDS FROM 22N97W TO INLAND OVER
MEXICO JUST E OF VERACRUZ GENERATING SCATTERED SHOWERS/ISOLATED
THUNDERSTORMS WITHIN 60 NM E OF THE SURFACE TROUGH AND W OF THE
TROUGH TO INLAND OVER MEXICO. THIS IS LEAVING THE REMAINDER OF
THE GULF UNDER CLEAR SKIES THIS MORNING. A SURFACE RIDGE EXTENDS
FROM THE ATLC ACROSS FLORIDA TO A 1018 MB HIGH NEAR 28N83W TO
TEXAS. THE SURFACE RIDGE WILL PERSIST ALONG 28N/29N THROUGH TUE.

CARIBBEAN SEA...
AN UPPER TROUGH OVER THE GULF OF MEXICO IS DRAWING UPPER
MOISTURE ACROSS THE FAR NW CARIBBEAN. SCATTERED SHOWERS/ISOLATED
THUNDERSTORMS ARE FROM 17N-19N BETWEEN SW HAITI AND E JAMAICA.
NOAA/NESDIS AEROSOL PRODUCT AND THE LAST VISIBLE SATELLITE
IMAGERY INDICATES THAT A PLUMB OF AEROSOLS OR SAHARAN DUST
COVERS THE CARIBBEAN LIMITING SHOWERS AND DEEP CONVECTION.
HOWEVER THE EASTERLY TRADE WINDS ARE ALLOWING ISOLATED LOW LEVEL
SHOWERS TO FORM OVER THE E CARIBBEAN E OF 70W LEAVING THE
REMAINDER OF THE CARIBBEAN WITH FAIR BUT HAZY SKIES THIS
MORNING. A PERSISTENT STRONG ATLC SURFACE RIDGE WILL MAINTAIN
STRONG TRADE WINDS ACROSS THE CARIBBEAN WITH MINIMAL GALE FORCE
WINDS ALONG THE NW COAST OF COLOMBIA THROUGH MON MORNING.
TROPICAL WAVE IN THE CENTRAL CARIBBEAN WILL MOVE W ACROSS THE
BASIN THROUGH THE WEEKEND. A SECOND TROPICAL WAVE WILL ENTER THE
E CARIBBEAN SUN NIGHT.

...HISPANIOLA...
SKIES REMAIN MOSTLY CLEAR ACROSS THE ISLAND THIS MORNING.
ALTHOUGH AN UPPER LOW N OF THE ISLAND EXTENDS AN UPPER TROUGH TO
OVER THE ISLAND...THE STRONG SUBSIDENCE AND AEROSOLS OR SAHARAN
DUST IS LIMITING CONVECTION TO POSSIBLE ISOLATED SHOWERS.
SHOWERS COULD INCREASE SOMEWHAT TODAY AS THE CENTRAL CARIBBEAN
TROPICAL WAVE MOVES W JUST S OF THE ISLAND. OTHERWISE EXPECT
ONLY POSSIBLE ISOLATED AFTERNOON SHOWERS THROUGH THE FIRST OF
NEXT WEEK.

ATLANTIC OCEAN...
AN UPPER RIDGE IS ANCHORED NEAR 23N77W COVERING THE W ATLC W OF
76W. THE UPPER LOW N OF HISPANIOLA IS CENTERED NEAR 26N70W AND
IS GENERATING ISOLATED SHOWERS AND POSSIBLE ISOLATED
THUNDERSTORMS FROM 25N-30N BETWEEN 66W-72W. A PAIR OF WEAK
SURFACE TROUGHS ARE IN THE CENTRAL ATLC...ONE EXTENDING FROM
28N50W TO 24N48W AND THE SECOND FROM 30N56W TO 24N55W WITH
SCATTERED SHOWERS AND POSSIBLE ISOLATED THUNDERSTORMS FROM 24N-
26N BETWEEN 52W-54W. THE REMAINDER OF THE ATLC IS DOMINATED BY A
SURFACE RIDGE ANCHORED BY A 1030 MB HIGH N OF THE AREA NEAR
34N44W AND EXTENDING A RIDGE AXIS THROUGH 32N56W TO ACROSS
CENTRAL FLORIDA AND INTO THE GULF OF MEXICO. NOAA/NESDIS AEROSOL
PRODUCT AND THE FIRST VISIBLE SATELLITE IMAGERY INDICATES THAT A
LARGE DENSE PLUMB OF AEROSOLS OR SAHARAN DUST COVERS THE TROPICS
N OF THE ITCZ TO 24N/25N INTO THE CARIBBEAN. THE SURFACE RIDGE
WILL PERSIST THROUGH TUE.

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

$$
PAW



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