[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 151043
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 AM EDT FRI 15 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 4N18W 5N28W 3N39W 1N52W.
CLUSTERS OF SCATTERED/NUMEROUS STRONG CONVECTION ARE FROM 1N TO
5N E OF 10W TO ACROSS THE PRIME MERIDIAN. AREA OF SCATTERED
MODERATE/STRONG CONVECTION ARE S OF 7N FROM 13W-21W. CLUSTERS OF
SCATTERED MODERATE/ISOLATED STRONG CONVECTION ARE S OF 5N W OF
21W TO INLAND OVER SOUTH AMERICA.

...DISCUSSION...

GULF OF MEXICO INTO THE W ATLANTIC...
SURFACE RIDGE OF HIGH PRESSURE CONTINUES TO BUILD SLOWLY DOWN
THE E SLOPES OF THE SIERRA MADRES AND OVER THE GULF WITH THE
MID/UPPER LEVEL RIDGING ALONG 96W. PACIFIC MOISTURE IS BEING
ADVECTED ACROSS N MEXICO AND TEXAS TO OVER THE W GULF W OF 92W.
A COMPLEX AREA OF LOW PRESSURE/STORM CENTER CONTINUES OVER THE W
ATLC. THIS SYSTEM IS LINKED TO A CUT-OFF UPPER LOW CENTERED JUST
N OF THE REGION NEAR 33N74W WITH BROAD TROUGHING REACHING DOWN
INTO THE NW CARIBBEAN AND NW/W UPPER WINDS FLOWING ACROSS THE
GULF AREA. THE COLD FRONT NOW EXTENDS JUST W OF BERMUDA THROUGH
32N66W SW ACROSS THE SOUTH/CENTRAL BAHAMAS NEAR 23N74W OVER
CENTRAL CUBA INTO THE CARIBBEAN. NUMEROUS SHOWERS/THUNDERSTORMS
ARE WITHIN 120 NM E OF THE FRONT FROM 23N-28N AND SCATTERED
SHOWERS/ISOLATED THUNDERSTORMS EXTENDING OUT UP TO 200 NM E OF
THE FRONT N OF 28N ALL DUE TO FAVORABLE UPPER LEVEL DIFFLUENCE
AND AN UPPER LEVEL JET WITH WINDS TO 110 KT SWEEPING ACROSS THE
E GULF...S FLORIDA...THEN NE OVER BERMUDA. SCATTERED SHOWERS ARE
WITHIN 200 NM OF EITHER SIDE OF THE REMAINDER OF THE FRONT.
MID-LEVEL INSTABILITY ASSOCIATED WITH THE CUT-OFF LOW IS ALSO
PRODUCING A BAND OF LOW CLOUDS OVER THE W ATLC N OF A SURFACE
TROUGH THAT EXTENDS THROUGH 32N72W OVER THE FLORIDA KEYS TO NEAR
25N82W. N/NE SURFACE FLOW DOMINATES THE GULF BEHIND THE FRONT
WITH SCATTERED LOW CLOUDS DOTTING THE REGION. THIS SURFACE FLOW
WILL TURN MORE EASTERLY OVER THE NEXT 24 HOURS AS THE COLD FRONT
MOVES INTO THE CENTRAL ATLC.

CARIBBEAN...
MID/UPPER LEVEL TROUGH OVER THE GULF AND W ATLC DIPS INTO THE NW
CARIBBEAN N OF 19N W OF 75W WITH THE ASSOCIATED COLD FRONT
ENTERING THE CARIBBEAN ACROSS CENTRAL CUBA NEAR 21N78W EXTENDING
SSW ALONG 19N84W INTO THE GULF OF HONDURAS TO THE COAST OF
HONDURAS NEAR 15N88W. SCATTERED SHOWERS/THUNDERSTORMS ARE S OF
18N W OF THE FRONT TO INLAND OVER BELIZE WITH ISOLATED SHOWERS
WITHIN 150 NM E OF THE FRONT N OF 18N. WESTERLY UPPER FLOW
DOMINATES THE REMAINDER OF THE AREA SPREADING A DEEPER DRY AIR
MASS OVER THE AREA SE OF THE FRONT. THE ILL-DEFINED SOUTH
AMERICAN UPPER HIGH REMAINS...ALTHOUGH THE ANTICYCLONIC FLOW IS
WEAKER AND HELD FURTHER S CIRCULATING ACROSS THE LESSER
ANTILLES. THE COLD FRONT WILL CONTINUE SLIDE E OVER THE NEXT
COUPLE OF DAYS...ALTHOUGH IT WILL BEGIN TO WEAKEN LATER TODAY
INTO TONIGHT...SHOWERS WILL CONTINUE ACROSS THE REMAINDER OF THE
GREATER ANTILLES.

ATLANTIC...
DEEP-LAYERED TROUGH CONTINUES TO SPREAD E ACROSS THE W ATLC AS
THE CUT-OFF UPPER LOW REMAINS NEARLY STATIONARY AND THE
ASSOCIATED COLD FRONT WILL MOVE E OF BERMUDA DURING THE DAY
TODAY. THE REMAINDER OF THE ATLC BASIN IS DOMINATED BY
BROAD...STRONG SURFACE HIGH PRESSURE WITH THE MAIN RIDGE ALONG
32N38W TO N OF THE LEEWARD ISLANDS NEAR 22N63W. THE UPPER FLOW
IS DOMINATED BY TROUGH OVER THE CENTRAL ATLC WITH A WEAKENING
UPPER CUT-OFF LOW CENTERED NEAR 22N38W. THE STRONGEST UPPER
LEVEL WESTERLY FLOW CONTINUES TO BE SUPPRESSED TO THE S THUS
KEEPING THE ITCZ CLOSER TO THE EQUATOR OVER THE W TROPICAL ATLC.
ITCZ CONVECTION CONTINUES TO BE VERY ACTIVE ESPECIALLY E OF 30W
WHERE THE VERTICAL SHEAR IS NOT QUITE AS STRONG.

$$
WALLACE



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