[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 161042
TWDAT

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

...ITCZ...

ITCZ AXIS IS CENTERED ALONG 8N10W 5N22W 3N31W 2N40W S OF THE
EQUATOR AND INLAND OVER SOUTH AMERICA NEAR 46W. LARGE AREA OF
SCATTERED/MODERATE STRONG CONVECTION IS FROM 1N-9N BETWEEN
12W-17W. CLUSTERS OF SCATTERED MODERATE/ISOLATED STRONG
CONVECTION ARE WITHIN 100 NM OF 2N FROM 1W-7W AND WITHIN 120 NM
OF 4N FROM 33W TO INLAND OVER SOUTH AMERICA.

...DISCUSSION...

GULF OF MEXICO...
SURFACE RIDGE OF HIGH PRESSURE CONTINUES OVER THE E SLOPES OF
THE SIERRA MADRES TOWARD THE GULF OF TEHUANTEPEC WITH THE MEAN
AXIS SHIFTING EASTWARD OVER THE SE UNITED STATES. MID/UPPER
LEVEL RIDGING ALONG 87W. SURFACE NE/E WINDS CONTINUE TO
DOMINATE THE GULF WITH SCATTERED COLD STRATOCUMULUS CLOUDS OVER
THE S GULF S OF 26N.

CARIBBEAN...
REMNANTS OF THE MID/UPPER LEVEL TROUGH AND ASSOCIATED W ATLC
COLD FRONT REMAINS ONLY ACROSS HISPANIOLA. THE NEAR STATIONARY
SURFACE TROUGH EXTENDS FROM HAITI ACROSS JAMAICA TO INLAND OVER
NICARAGUA/HONDURAS ALONG THE BORDER. LOW LEVEL MOISTURE POOLING
REMAINS ALONG THE SURFACE TROUGH WITH BROKEN TO OVERCAST LOW
CLOUDS AND ISOLATED SHOWERS WITHIN 120/180 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 WITHIN 120 NM OF 17N E OF 80W.

ATLANTIC...
THE PRIMARY WEATHER MAKER FOR THE DAY REMAINS THE STRONG
MID/UPPER LEVEL LONGWAVE TROUGH OFF THE EASTERN SEABOARD OF THE
UNITED STATES HELPING TO ENERGIZE A COMPLEX AREA OF LOW PRESSURE
WITH A WEAKENING STORM CENTER N OF THE REGION AND GALE
CONDITIONS IN OUR WATERS. THE UPPER LEVEL CUT OFF LOW IS NEARLY
VERTICALLY STACKED WITH THE 1006 MB SURFACE LOW CENTERED NEAR
32N72W AND BOTH ARE FORECASTED TO DRIFT A BIT E/SE OVER THE NEXT
DAY. ASSOCIATED SURFACE COLD FRONT LIES WELL E OF LOW CENTER
ALONG 32N61W 25N64W TO OVER HISPANIOLA INTO THE CARIBBEAN.
SCATTERED SHOWERS/ISOLATED THUNDERSTORMS ARE WITHIN 150 NM E OF
THE FRONT FROM 22N-28N THEN EXPANDING TO WITHIN 120 NM OF EITHER
SIDE OF THE FRONT N OF 28N. A SURFACE TROUGH EXTENDS ALONG
32N66W SW ACROSS THE CENTRAL BAHAMAS TO THE COAST OF CUBA NEAR
21N76W. THIS FEATURE IS NEAR VERTICALLY STACKED WITH MAXIMUM
MID/UPPER LEVEL TROUGH AND IS THE BOUNDARY OF THE DRIER
CONTINENTAL AIR. N/NE SURFACE FLOW DOMINATES THE W ATLC BEHIND
THE FRONT WITH BROKEN/OVERCAST LOW CLOUDS WITHIN 120 NM OF LINE
FROM 27N79W TO BEYOND 32N77W. THE REMAINDER OF THE ATLC BASIN
REMAINS DOMINATED BY BROAD...STRONG SURFACE HIGH PRESSURE WITH
AXIS EXTENDING SW FROM A 1032 MB HIGH CENTERED JUST N OF THE
REGION NEAR 35N32W 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 WEAKENING BUT PERSISTENT CENTRAL
ATLC TROUGH WITH A VERY WEAK UPPER LOW CENTERED NEAR 24N36W. 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 13N30W ACROSS THE CAPE VERDE ISLANDS TO OVER AFRICA
NEAR 20N16W. THIS IS HELPING TO KEEP ITCZ RELATED CONVECTION
FURTHER S...PARTICULARLY E OF 20W WHERE VERTICAL WIND SHEAR IS
QUITE LOW.

$$
WALLACE



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