[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 202346
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT TUE MAY 20 2008

TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL
AMERICA...THE GULF OF MEXICO...THE CARIBBEAN SEA...NORTHERN
SECTIONS OF SOUTH AMERICA...AND THE ATLANTIC OCEAN TO THE
AFRICAN COAST FROM THE EQUATOR TO 32N. THE FOLLOWING
INFORMATION IS BASED ON SATELLITE IMAGERY...METEOROLOGICAL
ANALYSIS...WEATHER OBSERVATIONS...AND RADAR.

BASED ON 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
2315 UTC.

...TROPICAL WAVES...

TROPICAL WAVE IS ALONG 18W/19W S OF 12N MOVING W 15 KT.
SATELLITE IMAGERY SHOWS BROAD LOW-MID LEVEL CYCLONIC TURNING
FOCUSED ALONG THE AXIS NEAR 7N. SCATTERED SHOWERS ARE WITHIN 120
NM W OF THE AXIS FROM 8N-11N EMBEDDED WITHIN THE ITCZ. ALSO
MIMIC TPW ANIMATION FROM CIMSS SHOWS NORTHERN MOISTURE SURGE
COMING OFF THE W AFRICAN COAST DURING THE PREVIOUS 12 HOURS.

TROPICAL WAVE IS ALONG 49W S OF 11N MOVING W 10-15 KT. SCATTERED
SHOWERS AND TSTMS COVER A FAIRLY LARGE 420 NM AREA EITHER SIDE
OF THE AXIS FROM 2N-7N...ENHANCED BY A LARGE AMPLITUDE UPPER
TROUGH. THE GFS MODEL GUIDANCE CONTINUES TO SHOW VERY SLIGHT
LOWER LEVEL CYCLONIC CURVATURE WITH MOST PRECIPITATION EMBEDDED
WITHIN THE ITCZ.

TROPICAL WAVE IS ALONG 74W S OF 13N ESTIMATED TO BE MOVING W
10-15 KT. POSITION IS BASED ON A WESTWARD MOISTURE SURGE
EVIDENT ON THE MIMIC TPW ANIMATION AND FITS WELL WITH LONG TERM
CONTINUITY. REGARDLESS OF THE EXACT LOCATION... THE WAVE REMAINS
WEAK AND IS ENHANCING SCATTERED MODERATE/ISOLATED STRONG
CONVECTION ACROSS CENTRAL COLOMBIA AND PORTIONS OF COASTAL
N COLOMBIA.

...THE ITCZ...
ITCZ AXIS IS CENTERED ALONG 7N10W 7N17W 6N20W 1N35W 4N46W AND
INTO NE BRAZIL NEAR 4N52W. SCATTERED MODERATE CONVECTION IS FROM
5N-8N BETWEEN 10W-15W. SIMILAR CONVECTION IS WITHIN 120-150 NM
ON EITHER SIDE OF THE AXIS BETWEEN 39W-52W.

...DISCUSSION...

GULF OF MEXICO...
STRONG SW TO W FLOW ALOFT LIES OVER THE REGION MOISTENING THE
MID AND UPPER LEVELS. THIS UPPER REGIME IN COMBINATION WITH A
LINGERING SURFACE TROUGH FROM N FLORIDA TO 25N88W IS TRIGGERING
SCATTERED SHOWERS AND TSTMS FROM VERO BEACH FLORIDA TO N OF FORT
MYERS AND INTO THE E GULF NEAR 26N84W. ELSEWHERE ACROSS THE GULF
AS THE AFOREMENTIONED SURFACE TROUGH CONTINUES TO WEAKEN DURING
THE NEXT 12 TO 24 HOURS...SOUTHERLY SURFACE FLOW IS EXPECTED TO
RETURN OVER MUCH OF THE GULF.

CARIBBEAN SEA...
A 1010 MB SURFACE LOW PRESSURE IS CENTERED NEAR 9N81W OFFSHORE
OF W PANAMA. MUCH OF THE AFTERNOON CONVECTION ASSOCIATED WITH
THE LOW IN THE SW CARIBBEAN SEA HAS DISSIPATED WITH ONLY
SCATTERED SHOWERS AND TSTMS REMAINING ACROSS INLAND COSTA RICA
AND NICARAGUA. A SUBSIDENT ENVIRONMENT IS IN PLACE ACROSS MUCH
OF THE REMAINDER OF THE CARIBBEAN SEA WITH A VERY BROAD
MID-UPPER LEVEL RIDGE CENTERED NEAR 15N71W...ALLOWING FAIR
WEATHER TO DOMINATE. EASTERLY TRADES OF 10-15 KT ARE BLOWING
OVER THE BASIN AND THIS IS EXPECTED TO CHANGE LITTLE DURING THE
NEXT 24 HOURS.

ATLANTIC OCEAN...
BROAD UPPER TROUGH COVERS THE E US AND NW ATLC WITH THE
ASSOCIATED FRONT WELL NORTH OF THE AREA. BROAD UPPER RIDGE
COVERS THE W ATLC INTO THE CENTRAL ATLC W OF 45W ANCHORED IN THE
CARIBBEAN WITH THE AXIS EXTENDING ACROSS E CUBA TO BEYOND
32N45W. BROAD UPPER TROUGH COVERS THE REMAINDER OF THE CENTRAL
ATLC TO THE E ATLC N OF 10N BETWEEN 23W-45W. A SURFACE RIDGE
DOMINATES THE ATLC N OF 15N E OF 73W ANCHORED BY A 1021 MB HIGH
CENTERED NEAR 27N53W AND A SIMILAR HIGH CENTERED S OF THE AZORES
NEAR 33N27W. ONLY SIGNIFICANT PRECIPITATION TO NOTE IS WITH
WEAKENING SURFACE TROUGH ACROSS CENTRAL FLORIDA THAT IS
PRODUCING SCATTERED SHOWERS AND ISOLATED TSTMS OFFSHORE OF
CENTRAL FLORIDA AND N OF THE BAHAMAS IN THE W ATLC.

$$
HUFFMAN/WALTON


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