[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 181052
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 AM EDT MON 18 APR 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1015 UTC.

...ITCZ...

ITCZ AXIS IS CENTERED ALONG 7N10W 6N16W 4N25W 4N42W 2N52W.
SCATTERED MODERATE/STRONG CONVECTION IS WITHIN 120 NM OF THE
AXIS FROM 25W-31W AND WITHIN 90 NM N OF THE AXIS FROM 33W-36W.
SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS WITHIN 75 NM S
OF THE AXIS FROM 21W-25W. CLUSTERS OF SIMILAR CONVECTION ARE
FROM 4N TO S OF THE EQUATOR E OF 37W TO ACROSS THE PRIME
MERIDIAN.

...DISCUSSION...

GULF OF MEXICO INTO THE FAR W ATLANTIC...
A 1026 MB HIGH IS CENTERED OVER SE ALABAMA/SW GEORGIA WITH A
BROAD RIDGE EXTENDING S INTO THE GULF OF MEXICO AND INTO THE W
ATLC. UPPER LEVEL RIDGING EXTENDS FROM THE E PACIFIC ACROSS
MEXICO INTO TEXAS TO JUST W OF THE UPPER MISSISSIPPI VALLEY.
THIS IS ADVECTING PACIFIC MOISTURE OVER MEXICO/TEXAS AND INTO
THE NW GULF. OVER THE E GULF...A MID/UPPER TROUGH EXTENDS FROM
THE CANADIAN MARITIMES SW ALONG THE EASTERN SEABOARD OF THE U.S.
THROUGH 32N71W TO E CUBA NEAR 22N75W. SERIES OF UPPER LOWS ARE
ROTATING THROUGH THE TROUGH MOSTLY N OF THE REGION WITH ONE NEAR
31N72W. THIS SYSTEM IS RESPONSIBLE FOR THE STORM AND GALE
CONDITIONS OVER THE W ATLC DURING THE PAST WEEKEND. MODERATE/
STRONG SUBSIDENCE REMAINS OVER THE FAR E GULF ACROSS FLORIDA
INTO THE W ATLC TO 66W. AT THE SURFACE...EASTERLY WINDS PREVAIL
ACROSS THE GULF EXCEPT IN THE AREA OF A WEAKENING SURFACE TROUGH
THAT EXTENDS IS FROM APALACHEE BAY ACROSS THE FLORIDA KEYS TO
THE STRAITS OF FLORIDA. OVERALL SKIES ACROSS THE GULF REMAIN
FAIR WITH ISOLATED PATCHES OF LOW LEVEL CLOUDS DOTING THE W
GULF.

CARIBBEAN...
A NEAR STATIONARY SURFACE TROUGH REMAINS OVER THE W PART OF THE
CARIBBEAN STRETCHING FROM HISPANIOLA SW ALONG 16N81W TO COSTA
RICA. ENOUGH LOW-LEVEL CONVERGENCE AND MOISTURE REMAIN TO
PRODUCE SCATTERED SHOWERS/THUNDERSTORMS WITHIN 150/180 NM NW OF
THE AXIS. SCATTERED MODERATE CONVECTION IS MOVING OFF THE COAST
OF COSTA RICA AND W PANAMA S OF 12N. A HIGH AMPLIFIED UPPER
RIDGE STRETCHES FROM THE W TROPICAL ATLC...E OF THE LESSER
ANTILLES ALONG 60W TO 20N THEN NE OVER THE CENTRAL ATLC. THIS IS
ALLOWING DEEP TROPICAL MOISTURE TO BE ADVECTED N OVER THE
CENTRAL CARIBBEAN MAINLY IN THE FORM OF HIGH CLOUDS.

ATLANTIC...
THE MID/UPPER TROUGH OVER THE FAR W ATLC THAT GENERATED STORM
AND GALE CONDITIONS OVER THE AREA DURING THE PAST WEEKEND HAS
WEAKENED WITH THE ASSOCIATED OCCLUDED FRONT NOW BEING WELL N OF
THE REGION WITH A WEAKENING STATIONARY FRONT EXTENDING THROUGH
32N55W SW TO 27N60W THEN DISSIPATING OVER HISPANIOLA. A
SECONDARY BOUNDARY...SURFACE TROUGH EXTENDS THROUGH 32N62W ALONG
26N67W TO THE S BAHAMAS NEAR 22N72W IS RAPIDLY APPROACHING THE
REMNANTS OF STATIONARY FRONT AND WILL BECOME THE PRIMER FEATURE
OVER THE NEXT 12 TO 24 HOURS. SCATTERED SHOWERS/ISOLATED
THUNDERSTORMS ARE WITHIN 90 NM OF EITHER SIDE OF THE FRONT N OF
26N. OVERCAST LOW/MID CLOUDS WITH SCATTERED SHOWERS ARE WITHIN
200 NM W OF THE REMAINDER OF THE FRONTAL BOUNDARY. SUBTROPICAL
1025 MB HIGH DOMINATES THE REMAINDER OF THE ATLC AND IS CENTERED
ABOUT NEAR 31N34W AND IS PRODUCING CONSISTENT NE/E TRADE WINDS
ACROSS MOST OF THE ATLC E OF 50W. A HIGH AMPLIFIED UPPER RIDGE
STRETCHES FROM THE W TROPICAL ATLC...E OF THE LESSER ANTILLES
ALONG 60W TO 20N THEN NE ACROSS THE CENTRAL ATLC TO BEYOND
32N44W. THIS RIDGE IS AMPLIFYING IN RESPONSE TO THE CUT-OFF
LOW/TROUGH OVER THE E ATLC. A TROUGH AXIS OVER THE E ATLC
EXTENDS FROM 28N27W THROUGH A CUT-OFF UPPER LOW CENTERED NEAR
21N33W INTO THE TROPICAL ATLC NEAR 8N45W. CYCLONIC FLOW AND
STRONG SUBSIDENCE EXTEND OUT UP TO 400 NM FROM THE AXIS. MUCH
DRIER UPPER LEVEL AIR IS FROM 20N-30N E OF 25W TO WELL INLAND
OVER AFRICA.

$$
WALLACE



WWWW
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