[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 160540
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 AM EDT SAT 16 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
0345 UTC.

...ITCZ...

ITCZ AXIS IS CENTERED ALONG 8N10W 4N20W 3N30W 2N50W. LARGE AREA
OF SCATTERED/NUMEROUS STRONG CONVECTION IS WITHIN 200 NM S OF
THE AXIS FROM 10W-14W. SCATTERED MODERATE/ISOLATED STRONG
CONVECTION IS WITHIN 100 NM N OF THE AXIS FROM 33W-37W AND
WITHIN 75 NM OF LINE 1N11W-4N9W. CLUSTERS OF SIMILAR CONVECTION
ARE FROM 2N-7N BETWEEN 12W-17W AND FROM THE EQUATOR TO 6N
BETWEEN 30W-52W.

...DISCUSSION...

GULF OF MEXICO...
SURFACE RIDGE OF HIGH PRESSURE CONTINUES TO SLIDE DOWN THE E
SLOPES OF THE SIERRA MADRES TOWARD THE GULF OF TEHUANTEPEC.
MID/UPPER LEVEL RIDGING ALONG 90W WITH WEAKENING PACIFIC
MOISTURE FEEDING INTO THE W GULF AND PORTIONS OF E TEXAS IS
HELPING TO SUPPORT WEAK SURFACE RIDGING ACROSS MUCH OF THE GULF
OF MEXICO. SURFACE NE/E WINDS ARE DOMINATING THE GULF WITH
SCATTERED COLD STRATOCUMULUS CLOUDS OVER THE SE GULF.

CARIBBEAN...
W ATLC MID/UPPER LEVEL TROUGH IS NO LONGER IN THE CARIBBEAN BUT
THE ASSOCIATED W ATLC COLD FRONT REMAINS...EXTENDING ACROSS NW
HAITI TO JAMAICA WITH THE REMAINDER TRANSITIONING TO A SURFACE
TROUGH TO INLAND OVER NICARAGUA/HONDURAS ALONG THE BORDER. LOW
LEVEL MOISTURE POOLING REMAINS ALONG THE BOUNDARY WITH
SCATTERED/BROKEN LOW CLOUDS WITH ISOLATED SHOWERS ARE WITHIN 150
NM W OF THE SURFACE TROUGH. ELSEWHERE ACROSS THE CARIBBEAN...A
MID/UPPER LEVEL RIDGE EXTENDS ACROSS THE E CARIBBEAN N ALONG 62W
WITH SW TO W WINDS ALOFT CONTINUING TO ADVECT UPPER LEVEL
MOISTURE FROM E PACIFIC ITCZ AND ISTHMUS OF PANAMA CONVECTION NE
ACROSS MOST OF THE CENTRAL AND EASTERN CARIBBEAN. THIS MOISTURE
APPEARS AS MOSTLY THIN CIRRUS S OF 18N E OF 83W.

ATLANTIC...
THE PRIMARY WEATHER MAKER FOR THE NIGHT IS A STRONG MID/UPPER
LEVEL LONGWAVE TROUGH ALONG THE EASTERN SEABOARD OF THE UNITED
STATES HELPING TO ENERGIZE A COMPLEX AREA OF LOW PRESSURE WITH A
STORM CENTER N OF THE REGION AND GALE CONDITIONS IN OUR WATERS.
THE UPPER LEVEL CUT OFF LOW IS VERTICALLY STACKED WITH THE 1000
MB SURFACE LOW CENTERED NEAR 33N72W AND BOTH ARE FORECASTED TO
DRIFT A BIT E OVER THE NEXT DAY OR SO. ASSOCIATED SURFACE COLD
FRONT LIES WELL E OF LOW CENTERS ALONG 32N62W 25N65W TO ACROSS
NW HAITI INTO THE CARIBBEAN. SHOWERS AND THUNDERSTORMS ARE
WITHIN 120 NM E OF THE FRONT FROM 22N-28N THEN EXPANDING TO
WITHIN 200 NM OF EITHER SIDE OF THE FRONT N OF 28N. A SURFACE
TROUGH EXTENDS ALONG 30N68W SW TO OVER THE CENTRAL BAHAMAS NEAR
25N75W. THIS FEATURE...NEAR VERTICALLY STACKED WITH MAXIMUM
MID/UPPER LEVEL TROUGH AND IS THE BOUNDARY OF THE DRIER
CONTINENTAL AIR. N/NE SURFACE FLOW DOMINATES THE GULF AND W ATLC
BEHIND THE FRONT WITH SCATTERED LOW CLOUDS DOTTING THE REGION.
THE GULF SURFACE FLOW WILL TURN MORE EASTERLY OVER THE NEXT 24
HOURS AS THE COLD FRONT MOVES INTO THE CENTRAL ATLC. THE
REMAINDER OF THE ATLC BASIN IS DOMINATED BY BROAD...STRONG
SURFACE HIGH PRESSURE WITH AXIS EXTENDING SW FROM A PARENT 1034
MB HIGH CENTER NEAR 35N29W...N OF THE AREA TO JUST NE OF THE
LEEWARD ISLANDS OF THE CARIBBEAN. UPPER FLOW ACROSS THE CENTRAL
AND EASTERN PORTIONS OF THE SUB-BASIN IS DOMINATED BY A CENTRAL
ATLC TROUGH WITH A VERY WEAK UPPER LOW NEAR 24N39W. THE
STRONGEST UPPER LEVEL WESTERLY FLOW CONTINUES TO BE SUPPRESSED
TO THE S...WITH A TROPICAL JET WITH WINDS FROM 70-90 KT WITHIN
120 NM OF 13N42W ACROSS THE CAPE VERDE ISLANDS TO OVER AFRICA
NEAR 20N16W. THIS IS HELPING TO KEEP ITCZ RELATED CONVECTION
FURTHER S...PARTICULARLY E OF 30W WHERE VERTICAL WIND SHEAR IS
QUITE LOW.

$$
WALLACE


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