[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 192353
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT THU MAY 19 2011

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
2315 UTC.

...TROPICAL WAVES...

TROPICAL WAVE WAS RELOCATED ALONG 62W/63W S OF 13N TO INLAND
OVER SOUTH AMERICA BASED ON SATELLITE IMAGERY...PRECIPITABLE
WATER IMAGERY..AND HOVMOLLER PLOTS MOVING W 10-15 KT. WAVE
REMAINS EMBEDDED WITHIN AN AREA OF DEEP LAYERED MOISTURE AS
DEPICTED ON THE TOTAL PRECIPITABLE WATER IMAGERY. SCATTERED
MODERATE/ISOLATED STRONG CONVECTION IS INLAND OVER VENEZUELA.

...THE ITCZ...

ITCZ AXIS IS ANALYZED ALONG 7N12W 5N15W 2N25W 1N37W TO INLAND
OVER SOUTH AMERICA AT THE EQUATOR NEAR 49W. CLUSTERS OF
SCATTERED/NUMEROUS STRONG CONVECTION ARE FROM 2N-5N BETWEEN
6W-14W. SMALL CLUSTERS OF SCATTERED MODERATE/STRONG CONVECTION
ARE WITHIN 75 NM EITHER SIDE OF THE ITCZ BETWEEN 16W-28W.

...DISCUSSION...

GULF OF MEXICO...
A BROAD UPPER RIDGE COVERS MOST OF THE GULF WITH THE AXIS ALONG
THE COAST OF MEXICO AND TEXAS TO INLAND OVER THE CENTRAL PLAIN
STATES AND COUPLED WITH THE BROAD UPPER TROUGH OVER THE W ATLC
IS GIVING THE GULF WATERS NW FLOW ALOFT. SOMEWHAT DRY STABLE AIR
ALOFT COVERS MUCH OF THE GULF LIMITING SHOWER ACTIVITY.
HOWEVER...LOW LEVEL MOISTURE REMAINS OVER THE NW GULF AND THE E
TO SE SURFACE FLOW CONTINUES TO BANK LOW LEVEL CLOUDS OVER THE
NW GULF N OF 27N W OF 92W. DENSE SMOKE IS OBSERVED ON VISIBLE
SATELLITE IMAGERY W OF LINE FROM NE YUCATAN PENINSULA/YUCATAN
CHANNEL TO E LOUISIANA NEAR GRAND ISLE FROM FIRES PREVIOUSLY
REPORTED OVER MEXICO ON NOAA SSD FIRE PRODUCTS. A WEAK SURFACE
RIDGE REMAINS OVER THE NE GULF WITH A 1018 MB HIGH OFF THE
FLORIDA COAST NEAR 29N84W LEAVING THE REMAINDER OF THE GULF
UNDER MOSTLY CLEAR SKIES THIS EVENING. SURFACE RIDGE OVER THE NE
GULF WILL DRIFT E THROUGH FRI NIGHT THEN INTO THE W ATLC ON SAT.
SE RETURN FLOW WILL CONTINUE OVER THE W GULF THROUGH TUE.

CARIBBEAN SEA...
A BROAD SHORTWAVE UPPER TROUGH EXTENDS FROM THE WINDWARD PASSAGE
TO THE SW CARIBBEAN ALONG 12N78W TO THE COAST OF CENTRAL AMERICA
NEAR THE PANAMA/COSTA RICA BORDER SUPPORTING A SURFACE TROUGH
THAT EXTENDS FROM 19N75W TO 12N74W WITH ISOLATED SHOWERS WITHIN
75 NM EITHER SIDE OF THE TROUGH AXIS. A SECOND SURFACE TROUGH
EXTENDS FROM THE SW ATLC THROUGH THE MONA PASSAGE TO 16N66W. A
BROAD UPPER RIDGE COVERS THE E CARIBBEAN E OF 70W WITH THE AXIS
E OF THE LESSER ANTILLES ALONG 57W/58W. DEEP LAYERED MOISTURE
REMAINS OVER THE E CARIBBEAN AND COUPLED WITH THE DIFFLUENT FLOW
ALOFT IS GENERATING SCATTERED SHOWERS OVER THE E CARIBBEAN E OF
72W ACROSS THE LESSER ANTILLES FROM SOUTH AMERICA ACROSS PUERTO
RICO AND HISPANIOLA. DRY STABLE AIR ALOFT REMAINS OVER THE W
CARIBBEAN LEAVING THE AREA W OF 77W UNDER MOSTLY CLEAR SKIES
THIS EVENING. SMOKE IS OBSERVED ON THE LAST VISIBLE SATELLITE
IMAGES W OF LINE FROM THE TIP OF HONDURAS/NICARAGUA TO THE NE
YUCATAN PENINSULA/YUCATAN CHANNEL. SURFACE TROUGH FROM WINDWARD
PASSAGE TO NORTHERN COLOMBIA WILL REMAIN NEARLY STATIONARY
THROUGH SAT. THE TROPICAL WAVE WILL MOVE SLOWLY INTO THE CENTRAL
CARIBBEAN THIS WEEKEND.

ATLANTIC OCEAN...
AN UPPER TROUGH COVERS THE W ATLC N OF 20N BETWEEN 67W-80W
SUPPORTING A COLD FRONT THAT ENTERS THE REGION NEAR 32N72W TO
30N74W WHERE IT DISSIPATES TO 29N75W WITH SCATTERED SHOWERS AND
POSSIBLE ISOLATED THUNDERSTORMS WITHIN 60 NM E OF THE FRONT. A
CONVERGENCE LINE/SURFACE TROUGH THAT EXTENDS FROM 30N79W TO OVER
ANDROS ISLAND NEAR 24N78W WITH SCATTERED SHOWERS/ISOLATED
THUNDERSTORMS WITHIN 75 NM E OF THE SURFACE TROUGH. AFTERNOON
THUNDERSTORMS HAVE DEVELOPED INLAND OVER S FLORIDA S OF LAKE
OKEECHOBEE WITH DEBRIS CLOUDS SPREADING E OVER THE SE COAST OF
FLORIDA. A SURFACE TROUGH IS TO THE SE OF THE BAHAMAS EXTENDING
FROM 23N72W E OF THE TURKS AND CAICOS THROUGH THE MONA PASSAGE
INTO THE NE CARIBBEAN. THIS TROUGH IS ALONG THE WESTERN EDGE OF
AN UPPER RIDGE THAT EXTENDS FROM SOUTH AMERICA ALONG 57W/58W TO
BEYOND 32N. ANOTHER SURFACE TROUGH IS TO THE NE EXTENDING ALONG
61W FROM 25N-32N. THE UPPER RIDGE IS SUPPLYING DIFFLUENT FLOW
ALOFT ENHANCING CLUSTERS OF SCATTERED SHOWERS AND POSSIBLE
ISOLATED THUNDERSTORMS OVER AN AREA FROM 28N TO THE THE GREATER
ANTILLES BETWEEN 62W-72W AND SCATTERED SHOWERS WITHIN 150 NM OF
LINE FROM THE LEEWARD ISLANDS NEAR 16N61W TO 32N57W. AN UPPER
TROUGH IN THE CENTRAL ATLC IS N OF 25N BETWEEN 38W-46W
SUPPORTING A WEAK 1021 MB LOW NEAR 31N48W AND A SURFACE TROUGH
EXTENDING ALONG 30N47W TO 27N50W WITH POSSIBLE ISOLATED SHOWERS
WITHIN 75 NM EITHER SIDE OF THE SURFACE TROUGH. THIS SURFACE
TROUGH SPLITS A BROAD SURFACE RIDGE THAT COVERS THE ATLC N OF
20N BETWEEN SW AFRICA AND 70W. SURFACE RIDGE WILL GRADUALLY
BUILD OVER THE W ATLC ALONG 30N THEN WILL WEAKEN SLIGHTLY AS IT
MOVES TO 28N OVER THE WEEKEND.

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

$$
PAW




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