[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 171800
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT TUE 17 MAY 2005

TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL
AMERICA... GULF OF MEXICO...CARIBBEAN SEA...NORTHEASTERN
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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1715 UTC.

...TROPICAL WAVES...

NEW TROPICAL WAVE INTRODUCED OFF THE COAST OF AFRICA ALONG 20W S
OF 13N MOVING WEST AT AN ESTIMATED SPEED OF 15 KT.  THE WAVE
INTRODUCTION IS BASED UPON A WELL-DEFINED SIGNATURE IN THE DAKAR
UPPER AIR TIMESECTION.  SATELLITE IMAGERY SHOWS THAT THE
CONVECTION ASSOCIATED WITH THIS SYSTEM IS CONFINED MAINLY TO THE
ITCZ AND IS NOT VERY WELL ORGANIZED.

CENTRAL ATLC TROPICAL WAVE ALONG 51W...OR JUST W OF FRENCH
GUIANA...S OF 14N MOVING W 20 KT.   CONVECTION ASSOCIATED WITH
THIS WAVE HAS MAINLY BEEN DEVELOPING ON THE SOUTHERN PART OF THE
WAVE WITHIN THE ITCZ.  THIS WAVE IS LOCATED AT THE LEADING EDGE
OF A SURGE OF AFRICAN DUST.

E CARIBBEAN TROPICAL WAVE ALONG 71W S OF 16N MOVING W 10 TO 15
KT. THE POSITION OF THIS WAVE WAS BASED MAINLY UPON
EXTRAPOLATION SINCE ANY EVIDENCE OF ROTATION ALONG THE WAVE AXIS
IS DIFFICULT TO PICK OUT IN SATELLITE IMAGERY.   WIDESPREAD
CLOUDINESS AND SCATTERED MODERATE CONVECTION IS NOTED AHEAD OF
THE ESTIMATED WAVE POSITION MAINLY COLOMBIA AND NW VENEZUELA
FROM 5N-11N BETWEEN 70W-76W. THIS ACTIVITY BRING LOCALLY HEAVY
RAINFALL AND POSSIBLE FLASH FLOODS AS IT CONTINUES WESTWARD.

...ITCZ...

ITCZ AXIS IS CENTERED ALONG 7N13W 7N20W 4N36W 5N51W.  A BAND OF
SCATTERED MODERATE CONVECTION IS CURRENTLY LOCATED FROM ABOUT
10N SOUTHWARD ALONG THE AFRICAN COAST.  A WIDESPREAD AREA OF
SCATTERED MODERATE CONVECTION CAN ALSO BE OBSERVED FROM ABOUT
6N27W TO 4N38W.  MORE WIDELY SCATTERED CONVECTION HAS DEVELOPED
FROM 4N46W WESTWARD TO JUST OFF THE SOUTH AMERICAN COAST AT
7N56W.

...DISCUSSION...

GULF OF MEXICO...
MID/UPPER LEVEL SHORTWAVE TROUGH IS PUSHING EWD THROUGH THE GULF
AND CAUSING SCATTERED SHOWERS AND WIDELY SCATTERED MODERATE
CONVECTION TO DEVELOP ALONG THE TAIL END OF A REMNANT FRONTAL
TROUGH FROM E LOUISIANA TO THE CENTRAL GULF NEAR 25N93W. THE
UPPER TROUGH AND ASSOCIATED SHOWER ACTIVITY IS EXPECTED TO
SLOWLY WEAKEN AS IT LIFTS NEWD AHEAD OF A SECOND...SHARPER...
TROUGH FORECAST TO MOVE INTO THE W GULF THU.  THIS SHOULD ALLOW
DEEP LAYERED MOISTURE TO THE SOUTH OVER THE CARIBBEAN TO MOVE
NWD TOWARD FLORIDA BY THE END OF THE WEEK POSSIBLY PRODUCING A
MORE UNSETTLED/WET REGIME.

CARIBBEAN AND W ATLANTIC...
MAIN WEATHER FEATURE CONTINUES TO BE A BROAD AND DISORGANIZED
AREA OF LOW PRESSURE WITH MULTIPLE LOW CENTERS. A 1007 MB
SURFACE LOW LOCATED TO THE EAST OF THE NICARAGUA COAST AT
13N79W CONTINUES TO SLOWLY DRIFT TO THE NNW WHILE A WEAKENING
1008 MB LOW OVER HAITI CONTINUES TO DRIFT TO THE EAST. THIS
COUPLED WITH MIDDLE TO UPPER LEVEL RIDGING/DIFFLUENCE AND AMPLE
DEEP LAYERED MOISTURE IS PRODUCING WIDESPREAD CLOUDINESS AND
SCATTERED SHOWERS/THUNDERSTORMS ACROSS THE AREA SE OF A LINE
FROM NICARAGUA TO JAMAICA.  THE STRONGEST AND MOST NUMEROUS OF
THIS ACTIVITY IS CURRENTLY FOCUSED OVER THE SW CARIBBEAN AND S
PORTIONS OF CENTRAL AMERICA WITH A SECOND AREA OVER 200-300 NM S
OF PUERTO RICO.  EXPECT THIS OVERALL SETUP TO LINGER THROUGH THE
END OF THE WEEK AS MIDDLE TO UPPER LEVEL RIDGING HOLDS STRONG.
AS SUCH...LOCALIZED HEAVY RAINFALL AND FLOODING IS POSSIBLE
ESPECIALLY OVER MOUNTAINOUS TERRAIN.

REMAINDER OF THE ATLANTIC...
PERSISTENT LOW LEVEL TROUGH OVER THE CENTRAL ATLC FROM 32N40W TO
THE LEEWARD ISLANDS SPLITS THE SUBTROPICAL RIDGE.  THE TROUGH IS
ALSO PROVIDING THE FOCUS FOR A LARGE AREA OF CLOUDINESS AND
SCATTERED SHOWERS/THUNDERSTORMS TO THE EAST FROM 18N-30N BETWEEN
38W-50W.  THIS ACTIVITY IS BEING ASSISTED BY A MIDDLE TO UPPER
LEVEL TROUGH MOVING EWD BETWEEN 50W-60W. EXPECT THE UPPER TROUGH
TO CONTINUE EWD DURING THE NEXT DAY OR SO WITH ASSOCIATED
SHOWERS/THUNDERSTORM PRIMARILY FOCUSED N OF 18N BETWEEN 40W-50W
ON WED THEN WEAKEN ON THU. ELSEWHERE OVER THE E ATLC...LARGE
SURGE OF AFRICAN DUST CONTINUES TO SPREAD WESTWARD WITH LEADING
EDGE ALONG 41W EXTENDING FROM THE ITCZ NWD TO ABOUT 20N.

$$
HALBACH/RHOME


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