[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 201103
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 AM EDT SAT JUN 20 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
1030 UTC.

...SPECIAL FEATURES...

A TIGHT PRESSURE GRADIENT BETWEEN HIGH PRESSURE OVER THE ATLC
EXTENDING INTO THE NORTHERN CARIBBEAN AND LOWER PRESSURE OVER
NORTHERN COLOMBIA SUPPORTS GALE FORCE WINDS FROM 11.5N TO 13.5N
BETWEEN 72W AND 77W WITH SEAS OF 10 TO 15 FT. GALE-FORCE WINDS
ARE FORECAST TO CONTINUE THROUGH SATURDAY AFTERNOON. PLEASE READ
THE HIGH SEAS FORECAST...MIAHSFAT2/FZNT02 KNHC...AND THE
OFFSHORE FORECAST...MIAOFFNT3/FZNT23 KNHC...FOR MORE DETAILS.

...TROPICAL WAVES...

A TROPICAL WAVE IS OVER THE EASTERN TROPICAL ATLC WITH AXIS NEAR
28W MOVING W AT 10 KT OVER THE PAST 24 HOURS. THE TOTAL
PRECIPITABLE WATER IMAGERY SHOW THE CENTRAL AND SOUTHERN WAVE
ENVIRONMENT CONTINUES EMBEDDED WITHIN A MODERATE TO HIGH SURGE
OF MOISTURE. IN THE NORTHERN WAVE ENVIRONMENT...METEOSAT
SATELLITE IMAGERY DEPICT SAHARAN DRY AIR AND DUST...THUS
LIMITING THE CONVECTION TO ISOLATED MODERATE WITHIN 120 NM
EITHER SIDE OF ITS AXIS S OF 09N.

A TROPICAL WAVE IS IN THE WESTERN TROPICAL ATLC WITH AXIS ALONG
45W MOVING W NEAR 10 KT OVER THE PAST 24 HOURS. THE TOTAL
PRECIPITABLE WATER IMAGERY SHOWS THE WAVE IS MAINLY EMBEDDED
WITHIN A MODERATE SURGE OF MOISTURE EXCEPT WITHIN 200 NM EITHER
SIDE OF ITS AXIS FROM 09N TO 12N WHERE ABUNDANT MOISTURE
SUPPORTS A SCATTERED MODERATE CONVECTION.

A TROPICAL WAVE IS IN THE SW CARIBBEAN BASIN WITH AXIS ALONG 78W
FROM 18N TO PANAMA MOVING W NEAR 15 KT OVER THE PAST 24 HOURS.
THE TOTAL PRECIPITABLE WATER IMAGERY SHOWS THE WAVE IS MAINLY
EMBEDDED WITHIN AN AREA OF RELATIVELY DRY AIR THAT IS HINDERING
DEEP CONVECTION.

...ITCZ/MONSOON TROUGH...

THE MONSOON TROUGH EXTENDS ACROSS AFRICA INTO THE TROPICAL ATLC
NEAR 11N15W AND CONTINUES TO 07N26W. THE ITCZ BEGINS NEAR 08N29W
AND CONTINUES TO E OF THE TROPICAL WAVE NEAR 09N42W THEN RESUMES
W OF THE WAVE NEAR 08N47W TO NORTHERN SOUTH AMERICA NEAR 06N57W.
BESIDES THE CONVECTION ASSOCIATED WITH THE TROPICAL
WAVES...SCATTERED MODERATE CONVECTION IS FROM 06N TO 11N BETWEEN
30W AND 41W. ISOLATED SHOWERS AND TSTMS ARE NOTED FROM 06N TO
10N E OF 20W.

...DISCUSSION...

THE GULF OF MEXICO...

AN UPPER RIDGE ANCHORED OVER WESTERN-CENTRAL MEXICO EXTENDS AN
AXIS NE INTO THE NW GULF TO OVER SOUTHERN LOUISIANA AND
MISSISSIPPI. THE REMAINDER OF THE GULF IS UNDER A LARGE UPPER
LOW CENTERED OVER THE NW YUCATAN PENINSULA. A BROAD SURFACE
RIDGE OVER THE ATLC EXTENDS AN AXIS SW TO W ACROSS THE FLORIDA
PENINSULA AND INTO THE GULF EXCEPT THE SW BASIN WHERE A SURFACE
TROUGH IS ANALYZED FROM 22N94W TO 18N93W. SHOWERS AND TSTMS ARE
AHEAD OF THE TROUGH S OF 24N W OF 95W. INFLOW OF MODERATE
MOISTURE FROM THE CARIBBEAN ENHANCES ISOLATED SHOWERS FROM 26N
TO 27N E OF 83W. SIMILAR SHOWER ACTIVITY IS OBSERVED WITHIN 120
NM OFF THE YUCATAN PENINSULA...INCLUDING THE YUCATAN
CHANNEL...BEING ENHANCED BY A DIFFLUENT ENVIRONMENT AT THE UPPER
LEVELS. WATER VAPOR IMAGERY SHOW DRY AIR ALOFT ACROSS THE
REMAINDER GULF...THUS FAVORING FAIR WEATHER. VARIABLE WINDS OF 5
KT ARE OVER THE EASTERN GULF AROUND A 1018 MB HIGH NEAR 27N84W.
EASTERLY TO SOUTHEASTERLY WIND FLOW OF 10 TO 15 KT IS OVER THE
REMAINDER BASIN. THE SURFACE HIGH PRESSURE CENTER IN THE NE GULF
WILL LINGER THROUGH THE FIRST OF NEXT WEEK.

THE CARIBBEAN SEA...

A GALE WARNING IS IN EFFECT FOR THE SW CARIBBEAN THROUGH
SATURDAY AFTERNOON. SEE SPECIAL FEATURES ABOVE. A TROPICAL WAVE
IS MOVING ACROSS THE SW BASIN. FOR DETAILS SEE THE TROPICAL
WAVES SECTION. AN UPPER RIDGE COVERS THE WESTERN AND THE CENTRAL
BASIN WHILE AND UPPER LEVEL LOW CENTERED NE OF PUERTO RICO
COVERS THE EASTERN CARIBBEAN. A MODERATE MOIST ENVIRONMENT OVER
THE W CARIBBEAN ENHANCES ISOLATED SHOWERS W OF 80W. METEOSAT
SATELLITE IMAGERY CONTINUE TO DEPICT SAHARAN DRY AIR AND DUST
COVERING THE E CARIBBEAN...THUS SUPPORTING HAZE. THE NEXT
TROPICAL WAVE WILL ENTER THE EASTERN CARIBBEAN MONDAY NIGHT
THROUGH TUESDAY MORNING.

...HISPANIOLA...

SHALLOW MOISTURE IS MOVING ACROSS HISPANIOLA SUPPORTING
CLOUDINESS OVER SW DOMINICAN REPUBLIC. METEOSAT SATELLITE
IMAGERY INDICATE THE PRESENCE OF SAHARAN DUST AND DRY AIR ACROSS
THE ISLAND...WHICH IS SUPPORTING HAZE IN SOME REGIONS. WATER
VAPOR IMAGERY ALSO DEPICT DRY AIR ALOFT. EXCEPT FOR THE TYPICAL
AFTERNOON SHOWERS...FAIR WEATHER IS EXPECTED THROUGH THE WEEKEND.

THE ATLANTIC OCEAN...

BROAD SURFACE RIDGING COVERS THE ATLC BEING ANCHORED BY A 1020
MB HIGH NEAR 28N74W. METEOSAT SATELLITE IMAGERY INDICATE SAHARAN
DRY AIR AND DUST COVERING THE TROPICS S OF 20N EXTENDING INTO
THE EASTERN CARIBBEAN...THUS LIMITING SHOWER ACTIVITY. FOR
INFORMATION ON TROPICAL WAVES SEE SECTION ABOVE. SURFACE RIDGING
WILL BE THE DOMINANT FEATURE THE NEXT THREE DAYS.

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

$$
NR
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