[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 010537
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
205 AM EDT THU AUG 01 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
0515 UTC.

...TROPICAL WAVES...
TROPICAL WAVE OVER THE W CARIBBEAN EXTENDS FROM 23N84W TO 15N83W
MOVING W 15-20 KT. WAVE IS EMBEDDED WITHIN AN AREA OF DEEP
MOISTURE THAT COVERS THE NW CARIBBEAN AS DEPICTED ON THE TOTAL
PRECIPITABLE WATER IMAGERY. HOWEVER...THE WAVE IS BECOMING LESS
DEFINED WITH NO ASSOCIATED DEEP CONVECTION. THE ACTIVITY IN THE
VICINITY IS DUE TO UPPER LEVEL FEATURES RATHER THAN THE TROPICAL
WAVE.

...ITCZ/MONSOON TROUGH...
THE MONSOON TROUGH EXTENDS ACROSS AFRICA INTO THE E TROPICAL
ATLC NEAR 21N17W AND CONTINUES THROUGH A WEAK 1011 MB LOW NEAR
18N21W THEN ALONG 10N31W TO 7N40W WHERE THE ITCZ BEGINS AND
CONTINUES ALONG 5N47W TO SOUTH AMERICA NEAR 5N53W. SCATTERED
MODERATE/ISOLATED STRONG CONVECTION IS WITHIN 120/150 NM ALONG
THE COAST OF W AFRICA BETWEEN THE GUINEA/GUINEA BISSAU BORDER TO
DAKAR SENEGAL.

...DISCUSSION...

GULF OF MEXICO...
A BROAD UPPER RIDGE ANCHORED OVER CENTRAL TEXAS EXTENDS SE
ACROSS THE GULF TO W CUBA GIVING THE GULF N TO E FLOW ALOFT. A
SHORTWAVE UPPER TROUGH EXTENDS ALONG THE COAST FROM NEAR
CHARLESTON SOUTH CAROLINA OVER JACKSONVILLE FLORIDA TO NEAR
GAINESVILLE FLORIDA GENERATING SCATTERED SHOWERS/ISOLATED
THUNDERSTORMS INLAND AND WITHIN 60 NM ALONG THE COAST OF FLORIDA
N OF TAMPA E OF PANAMA CITY. TOTAL PRECIPITABLE WATER IMAGERY
INDICATES THE DEEP MOISTURE THAT COVERS THE NW CARIBBEAN EXTENDS
N OVER THE E GULF OF MEXICO AND THE BAY OF CAMPECHE PROVIDING
THE MOISTURE LADEN ENVIRONMENT FOR THE EASTERLY UPPER FLOW AND
EASTERLY SURFACE FLOW TO COMBINE AND GENERATE CLUSTERS OF
SCATTERED SHOWERS/ISOLATED THUNDERSTORMS S OF 26N E OF 84W...S
OF 24N BETWEEN 84W-90W...AND S OF 21N BETWEEN 93W-96W IN THE BAY
OF CAMPECHE. THE SURFACE RIDGE ANCHORED IN THE ATLC EXTENDS
ACROSS FLORIDA TO TEXAS AND NE MEXICO WITH A PAIR OF WEAK 1018
MB HIGHS NEAR 29N84W AND 28N92W. WEAK SURFACE RIDGE WILL REMAIN
STATIONARY THROUGH FRI THEN DRIFT IN SLIGHTLY S SAT THROUGH MON.
THE NORTHERN PORTION OF THE WEAK CARIBBEAN TROPICAL WAVE WILL
MOVE INTO THE SE GULF TONIGHT AND INTO THU AS IT WEAKENS.

CARIBBEAN SEA...
THE UPPER RIDGE OVER THE GULF OF MEXICO CLIPS THE FAR NW
CARIBBEAN N OF 18N W OF 81W. A SECOND UPPER RIDGE COVERS THE SW
CARIBBEAN S OF 16N W OF 77W INDUCING AN UPPER TROUGH THAT
EXTENDS FROM NEAR JAMAICA TO OVER THE GULF OF HONDURAS. THE
UPPER LOW CENTERED OVER THE CENTRAL BAHAMAS DIPS S OVER THE
N/CENTRAL CARIBBEAN TO 18N BETWEEN THE WINDWARD PASSAGE AND 81W.
CLUSTERS OF SCATTERED SHOWERS/ISOLATED THUNDERSTORMS ARE N OF
18N TO OVER CUBA BETWEEN 75W-86W. A WEAK UPPER LOW IS OVER THE
VIRGIN ISLANDS LEAVING HISPANIOLA IN A CULL AREA BETWEEN THE
UPPER LOWS. ISOLATED SHOWERS ARE OVER THE NE CARIBBEAN N OF 16N
E OF THE MONA PASSAGE TO OVER THE LEEWARD ISLANDS. WATER VAPOR
IMAGERY INDICATES DRY STABLE AIR ALOFT DOMINATES MOST OF THE
CARIBBEAN E OF 77W. THE MONSOON TROUGH EXTENDS ALONG 9N/10N FROM
COLOMBIA TO COSTA RICA ARE GENERATING SCATTERED SHOWERS/
ISOLATED THUNDERSTORMS S OF 10N E OF 78W AND S OF 13N W OF 78W.
THE WEAK TROPICAL WAVE WILL ENTER THE SE GULF OF MEXICO TONIGHT
AND THU. A TIGHT PRESSURE GRADIENT WILL CONTINUE TO RESULT IN
FRESH TO STRONG TRADE WINDS ACROSS MUCH OF THE S/CENTRAL
CARIBBEAN THROUGH THE MON.

HISPANIOLA...
THE AFTERNOON SHOWERS/THUNDERSTORMS HAVE DIMINISHED AND SKIES
HAVE CLEARED ACROSS THE ENTIRE ISLAND WITH SOME LINGERING HIGH
CLOUDS OVER PORTIONS OF HAITI AND SW DOMINICAN REPUBLIC.
HISPANIOLA IS IN A CULL AREA BETWEEN AN UPPER LOW CENTERED OVER
THE CENTRAL BAHAMAS AND A SECOND CENTERED OVER THE VIRGIN
ISLANDS. THIS WEAK SECOND UPPER LOW WILL BE ABSORBED BY A BROAD
UPPER LOW IN THE CENTRAL ATLC AND WILL SHIFT W TO OVER
HISPANIOLA EARLY THE WEEKEND INCREASING PRECIPITATION OVER THE
ISLAND. AFTERNOON SHOWERS AND THUNDERSTORMS ARE STILL POSSIBLE
OVER THE NEXT FEW DAYS.

ATLANTIC OCEAN...
THE UPPER RIDGE OVER THE GULF OF MEXICO EXTENDS A RIDGE AXIS
ACROSS FLORIDA  NEAR DAYTONA BEACH TO BEYOND 32N71W PROVIDING
DIFFLUENCE ALOFT TO GENERATE SCATTERED SHOWERS/ISOLATED
THUNDERSTORMS NW OF LINE FROM DAYTONA BEACH FLORIDA TO BEYOND
32N77W. AN UPPER LOW IS TO THE S CENTERED OVER THE CENTRAL
BAHAMAS NEAR 24N77W AND EXTENDS S OVER CUBA SUPPORTING A SURFACE
TROUGH THAT EXTENDS FROM 26N73W TO 21N74W GENERATING SCATTERED
SHOWERS/THUNDERSTORMS FROM 22N-24N BETWEEN 74W-77W WITH CLUSTERS
OF SCATTERED SHOWERS/ISOLATED THUNDERSTORMS FROM 26N-29N BETWEEN
72W-77W. A REMNANT SURFACE TROUGH EXTENDS FROM 32N60W ALONG
30N63W TO 28N66W GENERATING ISOLATED SHOWERS AND POSSIBLE
ISOLATED THUNDERSTORMS 90 NM EITHER SIDE OF THE TROUGH. A SECOND
LARGER UPPER LOW IS IN THE CENTRAL ATLC NEAR 26N54W GENERATING
CLUSTERS OF SCATTERED SHOWERS/ISOLATED THUNDERSTORMS WITHIN
90/120 NM OF LINE FROM 33N52W TO 28N58W. A VERY BROAD UPPER
TROUGH OVER THE NE ATLC DIPS S TO 27N E OF 35W SUPPORTING A COLD
FRONT THAT EXTENDS INTO THE DISCUSSION AREA NEAR 32N24W TO
31N30W THEN NW TO BEYOND 32N38W. WATER VAPOR IMAGERY INDICATES
THIS IS A DRY STABLE AREA...THUS NO ASSOCIATED ACTIVITY. THE
REMAINDER OF THE ATLC IS DOMINATED BY A SURFACE RIDGE...WITH A
WEAKNESS IN THE IMMEDIATE VICINITY OF THE ABOVE COLD FRONT AND
IS ANCHORED BY A 1029 MB NW OF THE AZORES AND A WEAKER 1025 MB
HIGH NEAR 31N44W. SURFACE RIDGE WILL REMAIN NEARLY STATIONARY
THROUGH THU NIGHT THEN SHIFT S TO NEAR 27N FRI THROUGH MON. A
WEAK TROUGH OVER THE SE BAHAMAS WILL MOVE NW THROUGH THU NIGHT
AND N FRI WHILE DISSIPATING.

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

$$
PAW


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