[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 041034
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 AM EDT THU JUL 04 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1015 UTC.

...TROPICAL WAVES...
TROPICAL WAVE OVER THE CAPE VERDE ISLANDS EXTENDS FROM 22N24W TO
11N25W MOVING W NEAR 10 KT. WAVE REMAINS WITHIN A SURGE OF
MODERATE MOISTURE AS DEPICTED BY THE TOTAL PRECIPITABLE WATER
IMAGERY. A SWATH OF DRIER AIR IS BEING INTRODUCED ALONG THE WAVE
BY THE MID LEVEL SWIRL THAT IS CENTERED NEAR 18N25W. NO
ASSOCIATED DEEP CONVECTION.

TROPICAL WAVE IN THE CENTRAL TROPICAL ATLC EXTENDS FROM 18N38W
TO 7N49W MOVING W-NW 15-20 KT. WAVE REMAINS EMBEDDED WITHIN A
SURGE OF DEEP MOISTURE AS DEPICTED BY THE TOTAL PRECIPITABLE
WATER IMAGERY. SCATTERED SHOWERS/ISOLATED THUNDERSTORMS ARE
WITHIN 120 NM EITHER SIDE OF THE WAVE AXIS.

TROPICAL WAVE EXTENDS FROM 22N64W THROUGH THE MONA PASSAGE TO
15N68W IN THE E CARIBBEAN MOVING W-NW NEAR 15 KT. WAVE IS MOVING
INTO AN AREA OF MODERATE MOISTURE AS DEPICTED BY THE TOTAL
PRECIPITABLE WATER IMAGERY. SHOWER ACTIVITY OVER THE E CARIBBEAN
IS BEING ENHANCED BY THIS TROPICAL WAVE.

...ITCZ/MONSOON TROUGH...
THE MONSOON TROUGH EXTENDS ACROSS AFRICA INTO THE E TROPICAL
ATLC NEAR 11N15W AND CONTINUES ALONG 9N18W TO 7N25W WHERE THE
ITCZ BEGINS AND CONTINUES ALONG 8N32W 12N38W TO 13N42W.
SCATTERED MODERATE/STRONG CONVECTION IS WITHIN 120/150 NM OF
LINE FROM THE COAST OF SW AFRICA NEAR 6N10W TO 7N29W. CLUSTERS
OF SCATTERED MODERATE/ISOLATED STRONG CONVECTION ARE FROM 4N TO
S OF THE EQUATOR BETWEEN 43W-50W.

...DISCUSSION...

GULF OF MEXICO...
AN UPPER TROUGH COVERS THE GULF N OF 21N W OF 88W EXTENDING FROM
AN UPPER LOW OVER THE MISSOURI/KANSAS BORDER AND SUPPORTING A
SURFACE TROUGH THAT AT 04/0900 UTC EXTENDS INTO THE GULF FROM
NEAR PENSACOLA FLORIDA ACROSS THE MISSISSIPPI DELTA ALONG 28N91W
TO 26N95W. ISOLATED SHOWERS/THUNDERSTORMS ARE POSSIBLE WITHIN
60/75 NM EITHER SIDE OF THE TROUGH THE S PORTION OF THIS SURFACE
TROUGH HAS REMAINS OVER THE S GULF AND THE BAY OF CAMPECHE
EXTENDING FROM 24N90W TO S MEXICO NEAR 18N94W. SCATTERED
SHOWERS/ISOLATED THUNDERSTORMS ARE WITHIN 90/120 NM EITHER SIDE
OF THE TROUGH. AN UPPER RIDGE EXTENDS FROM THE YUCATAN PENINSULA
ALONG 25N85W TO OVER NE FLORIDA TO SOUTH CAROLINA AND IS
PROVIDING DIFFLUNCE ALOFT TO GENERATE SCATTERED SHOWERS/ISOLATED
THUNDERSTORMS E OF 90W. THE SURFACE RIDGE OVER THE ATLC BASIN
COVERS THE FAR E GULF. N GULF SURFACE TROUGH WILL DRIFT INTO THE
W GULF THROUGH THE WEEKEND IN PHASE WITH ANOTHER TROUGH IN THE
BAY OF CAMPECHE. WEAK SURFACE LOW WILL FORM ALONG THE TROUGH
OVER THE BAY OF CAMPECHE THROUGH LATE TODAY THEN MOVE W ACROSS
THE FAR SW GULF AND INTO THE COAST OF VERACRUZ THROUGH LATE FRI.
VERY ACTIVE WEATHER WILL CONTINUE OVER THE CENTRAL AND E GULF
THROUGH SAT. A SECOND SURFACE LOW MAY FORM OVER THE N/CENTRAL
GULF SUN THEN SHIFT N INTO SW LOUISIANA THROUGH MON.

CARIBBEAN SEA...
AN UPPER RIDGE COVERS THE CARIBBEAN W OF 70W AND IS ANCHORED
OVER THE YUCATAN PENINSULA. AN ELONGATED UPPER LOW IS CENTERED
OVER THE CENTRAL BAHAMAS AND EXTENDS S TO THE N COAST OF
HISPANIOLA AND W CUBA. THE UPPER RIDGE IS PROVIDING DIFFLUNCE
ALOFT TO GENERATE SCATTERED SHOWERS/ISOLATED THUNDERSTORMS N OF
19N W OF 74W AND WITHIN 60 NM ALONG THE COAST OF THE YUCATAN
PENINSULA S OF 20N. THE MONSOON TROUGH EXTENDS ACROSS OF PANAMA
ALONG 9N GENERATING ISOLATED SHOWERS AND POSSIBLE ISOLATED
THUNDERSTORMS S OF 12N W OF 82W AND S OF 10N E OF 82W. EASTERLY
TRADE WINDS ARE USHERING IN SOME SCATTERED LOW LEVEL SHOWERS
OVER THE FAR E CARIBBEAN FROM 13N-17N W OF THE TROPICAL WAVE TO
THE LESSER ANTILLES AND ARE BEING ENHANCED BY THIS TROPICAL
WAVE. TROPICAL WAVE WILL MOVE THROUGH THE CENTRAL CARIBBEAN
THROUGH FRI AND ACROSS W CARIBBEAN AND INTO CENTRAL AMERICA
THROUGH SAT. ATLC SURFACE RIDGE IS MAINTAINING FRESH TO STRONG
TRADE WINDS ACROSS THE CENTRAL CARIBBEAN THIS MORNING BUT WILL
DIMINISH SLIGHTLY AHEAD OF THE TROPICAL WAVE THEN INCREASE AGAIN
FRI BEHIND THE WAVE. ANOTHER TROPICAL WAVE OVER THE ATLC IS
EXPECTED TO REACH THE EASTERN CARIBBEAN EARLY NEXT WEEK.

HISPANIOLA...
CURRENTLY SKIES ARE CLEAR OVER MOST OF THE ISLAND THIS MORNING.
THE EXCEPTION IS N HAITI WHERE ISOLATED SHOWERS ARE POSSIBLE. AN
ELONGATED UPPER LOW CENTERED OVER THE CENTRAL BAHAMAS IS N OF
HISPANIOLA. GLOBAL MODELS SHOW THAT THIS UPPER LOW WILL CONTINUE
TO MOVE NW AWAY FROM HISPANIOLA ALLOWING ANOTHER UPPER LOW TO
MOVE IN FROM THE E ON SAT. A TROPICAL WAVE WILL MOVE ACROSS THE
ISLAND STARTING THIS MORNING EXITING EARLY FRI INCREASING THE
CHANCE OF SHOWERS/THUNDERSTORMS. THE TYPICAL AFTERNOON SHOWERS
AND THUNDERSTORMS WILL THEN REMAIN POSSIBLE OVER THE ISLAND
THROUGH THE WEEKEND.

ATLANTIC OCEAN...
THE UPPER RIDGE AXIS THAT EXTENDS FROM THE NW CARIBBEAN OVER THE
E GULF OF MEXICO AND CONTINUES TO PROVIDE ENOUGH DIFFLUNCE ALOFT
TO GENERATE ISOLATED SHOWERS AND POSSIBLE ISOLATED THUNDERSTORMS
WITHIN 75 NM ALONG THE COAST OF FLORIDA. AN ELONGATED UPPER LOW
IS CENTERED OVER THE CENTRAL BAHAMAS AND IS GENERATING SCATTERED
SHOWERS/ISOLATED THUNDERSTORMS FROM 20N-28N BETWEEN 70W-77W. A
LARGE SURFACE RIDGE DOMINATES THE ATLC ANCHORED BY A SERIES OF
HIGHS WELL N OF THE DISCUSSION AREA. A COLD FRONT IS APPROACHING
THE DISCUSSION AREA OVER THE CENTRAL ATLC. SURFACE RIDGE WILL
CHANGE LITTLE THROUGH SAT THEN WEAKEN SUN INTO MON. THE N
PORTION OF A TROPICAL WAVE MOVING ACROSS THE E CARIBBEAN WILL
MOVE W ACROSS THE SOUTHERN BAHAMAS THROUGH FRI.

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

$$
PAW


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