[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 200549
TWDAT

TROPICAL WEATHER DISCUSSION...
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 AM EDT FRI 20 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
0515 UTC.

...SPECIAL FEATURES...
HURRICANE ADRIAN IS MAKING LANDFALL ALONG THE COAST OF EL
SALVADOR. THIS SYSTEM IS EXPECTED TO BE DOWNGRADED AS IT MOVES
ACROSS CENTRAL AMERICA AND BECOME A TROPICAL DEPRESSION AS IT
MOVES INTO THE CARIBBEAN...BUT NOT REFORM INTO A TROPICAL STORM
OR HURRICANE AT THIS TIME. SEE LATEST NHC PUBLIC ADVISORY UNDER
AWIPS/WMO HEADERS MIATCPEP1/WTPZ31 KNHC AND THE FULL
FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMEP1/WTPZ21 KNHC
FOR MORE DETAILS.

...TROPICAL WAVES...

E ATLC TROPICAL WAVE IS ALONG 37W/38W S OF 13N MOVING W 10-15
KT. NEARBY CONVECTION REMAINS DISORGANIZED AND CONFINED WITHIN
THE ITCZ. AS SUCH...THERE IS LITTLE IN THE WAY OF A SATELLITE
SIGNATURE AND THE CURRENT WAVE POSITION IS BASED UPON
EXTRAPOLATION.

TROPICAL WAVE IS IN THE E CARIBBEAN AND VENEZUELA ALONG 67W/68W
S OF 16N MOVING W 10-15 KT. ASSOCIATED DEEP CONVECTION IS INLAND
OVER VENEZUELA.

W CARIBBEAN TROPICAL WAVE IS NOW IN THE PACIFIC REGION.

...ITCZ...

THE ITCZ AXIS IS CENTERED ALONG 10N10W 10N12W 6N23W 4N33W 3N45W
3N53W. SCATTERED/NUMEROUS STRONG CONVECTION IS MOVING OFF THE
COAST OF SIERRA LEONE WITHIN 45 NM ALONG THE COAST. LARGE AREAS
OF SCATTERED MODERATE/STRONG CONVECTION ARE WITHIN 200 NM OF THE
ITCZ AXIS ACROSS THE ENTIRE ATLANTIC.

...DISCUSSION...

GULF OF MEXICO...
WEAK SURFACE RIDGE EXTENDS FROM THE W ATLC INTO THE GULF OF
MEXICO AND SE UNITED STATES ALONG 30N ACROSS N FLORIDA TO E
TEXAS. EASTERLY WINDS PREVAIL ACROSS THE GULF. FAIR WEATHER
PREVAILS OVER THE GULF EXCEPT IN THE SE WHERE DEEP LAYERED
MOISTURE FROM THE CARIBBEAN IS BEING ADVECTED ACROSS CUBA TO
OVER S FLORIDA BRINGING SCATTERED SHOWERS S OF LAKE OKEECHOBEE.
IN THE UPPER LEVELS...MID/UPPER HIGH OVER NEW MEXICO IS MOVING
INTO N TEXAS WITH BROAD ANTICYCLONIC FLOW EXTENDING E OVER THE
NW GULF. A SHARP MID/UPPER TROUGH EXTENDS FROM OVER GEORGIA SW
ACROSS THE GULF TO THE WESTERN BAY OF CAMPECHE. CONFLUENT FLOW
NW OF THE TROUGH AND CONTINENTAL AIR ARE CREATING MODERATE
SUBSIDENCE WITH DRY/STABLE CONDITIONS ALOFT. NUMERICAL GUIDANCE
SUGGESTS THAT THE TROUGH WILL BECOME STATIONARY AND REMAIN
ESSENTIALLY STATIONARY THROUGH SAT. AS A RESULT...POINTS NW OF
THE CURRENT TROUGH AXIS SHOULD REMAIN ESSENTIALLY DRY AND
TRANQUIL. MEANWHILE...POINTS SE OF THE TROUGH AXIS WILL CONTINUE
TO EXPERIENCE UPPER LEVEL MOISTURE ADVECTION WITH ISOLATED
SHOWERS.

CARIBBEAN AND W ATLC. ...
A VERY UNSETTLED/WET PATTERN IS CURRENTLY UNFOLDING OVER THE NW
CARIBBEAN AND CENTRAL AMERICA COURTESY OF HURRICANE ADRIAN WHICH
IS MAKING LANDFALL ALONG THE COAST OF EL SALVADOR. THIS IS A
POTENTIALLY LIFE-THREATENING STORM OVER THE INLAND AREAS OF
NICARAGUA AND HONDURAS DUE TO LOCALLY HEAVY RAINFALL WITH
LIFE-THREATENING FLASH FLOODING AND MUDSLIDES ESPECIALLY IN
MOUNTAINOUS AREAS. DEEP-LAYERED MOISTURE WILL CONTINUE TO SURGE
NE OUT AHEAD OF ADRIAN PRODUCING INCREASING CLOUDINESS WITH
SHOWERS/THUNDERSTORMS ACROSS THE NW CARIBBEAN THIS MORNING.
SHOWERS/THUNDERSTORMS COULD BECOME LOCALLY NUMEROUS AS MOISTURE
INTERACTS WITH A SHARP TROUGH. MOISTURE AND ASSOCIATED
SHOWERS/THUNDERSTORMS ARE THEN EXPECTED TO SPREAD ACROSS CUBA
LATER TODAY. A 1006 MB LOW IS N OF THE MONA PASSAGE NEAR 23N67W.
IN THE UPPER LEVELS...BROAD MID/UPPER LEVEL RIDGE DOMINATES THE
ENTIRE CARIBBEAN WITH MEAN AXIS ALONG 68W INTO THE W ATLC
COVERING THE AREA W OF 45W. SUBTROPICAL JET WITH WINDS TO 100 KT
EXTENDS AROUND THE N PERIPHERY OF THE RIDGE FROM OVER S FLORIDA
ALONG 28N67W TO 25N50W. THE JET IS CREATING A HIGHLY DIFFLUENT
PATTERN ALOFT OVER THE NW CARIBBEAN. SCATTERED CLUSTERS OF
SHOWERS/THUNDERSTORMS ARE WITHIN 120 NM OF 20N FROM 54W-74W.
THIS DIFFLUENT FLOW WILL ACT TO FOCUS SCATTERED TO LOCALLY
NUMEROUS SHOWERS/THUNDERSTORMS OVER THE W CARIBBEAN THROUGH THE
MORNING AS MOISTURE ASSOCIATED WITH ADRIAN MOVES ACROSS THE
AREA. THIS WILL SET THE STAGE LOCALLY HEAVY RAINFALL SPREADING
OVER CUBA AND THE CAYMAN ISLANDS LATER TODAY.

ATLANTIC...
A 1009 MB LOW IS OVER THE CENTRAL ATLC NEAR 29N46W WITH A
SURFACE TROUGH EXTENDING SSW ALONG 23N47W TO 16N52W. IN THE
UPPER LEVELS...BROAD RIDGING OVER THE W ATLC IS MOVING INTO THE
CENTRAL ATLC S OF 30N W OF 45W. A DEEP LAYERED TROUGH IS OVER
THE NW ATLC N OF 30N W OF 40W. DIFFLUENCE NEAR 30N E OF THE
SURFACE LOW IS GENERATING OVERALL CLOUDINESS WITH SCATTERED
SHOWERS N OF 25N FROM 37W-47W. MID/UPPER LEVEL TROUGH OVER THE
CENTRAL ATLC IS N OF 7N BETWEEN 30W-45W AND A RIDGE OVER THE FAR
E ATLC EXTENDING FROM THE CAPE VERDE ISLANDS NNE BEYOND THE
CANARY ISLANDS WITH AN UPPER HIGH LOCATED NEAR 23N23W. THE UPPER
TROUGH IS EXPECTED BROADEN AS IT SHIFTS E TO ENCOMPASS THE E
ATLC. EXPECT LITTLE OVERALL MOTION OF THE SURFACE LOW N OF THE
CARIBBEAN DURING THE NEXT 24 HOURS...HOWEVER THE CENTRAL ATLC
LOW WILL DRIFT NORTHWARDS AND WEAKEN. NEW SURGE OF AFRICA DUST
COVERS THE E ATLC S OF 25N TO THE CAPE VERDE ISLANDS.

$$
WALLACE


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