000
AGXX40 KNHC 210448
MIMATS

MARINE WEATHER DISCUSSION   
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 
130 AM EDT FRI APR 21 2006

MARINE WEATHER DISCUSSION FOR GULF OF MEXICO...CARIBBEAN SEA AND 
SOUTHWEST NORTH ATLC S OF 31N W OF 55W.

MAJOR UPPER TROUGH DIGGING SE OVER SW ATLC TONIGHT. OPEN UPPER 
RIDGE FOLLOWING ALONG 80W. ON THE SURFACE THE TROUGH SUPPORTS A 
WEAK COLD FRONT OVER MID OCEAN MOVING E WITH LITTLE WIND. MOST 
AREAS PRESSURE GRADIENT WEAK.

FOR DAY 1 TROUGH CONTINUES TO LOWER HEIGHTS W OF 50W AS IT MOVES 
EWD. OPEN UPPER RIDGE MOVES SLOWLY E WHILE A NEW VORTEX MOVES TO 
THE MS VALLEY. ON THE SURFACE THE OLD COLD FRONT MOVES TO 55W 
WHILE THE WEAK POLAR AIRMASS FOLLOWING THE FRONT MOVES TO 29N72W 
AND STRENGTHENS SOME FROM 1015 MB TO 1022 MB. THIS WILL FAVOR AN 
INCREASE IN TRADES S OF 20N OVER THE CARIB. WEAK FRONT MOVES TO 
THE NW GULF COAST BUT WINDS REMAIN WEAK.

PROGRESSIVE PATTERN ALOFT WITH FIRST VORTEX CONTINUING EWD TO 
55W AND A SECOND ONE MOVING TO THE SE COAST DAY 2. ATLC COLD 
FRONT MOVES TO 50W WITH WINDS TO 20 KT N OF 28N. POLAR AIRMASS 
STRENGTHENS TO 1024 MB NEAR 30N68W THUS ATLC WINDS S OF 23N 
INCREASE SOME TO 20 KT. GULF COLD FRONT WEAKENS OVER ERN GULF 
DAY 2 WITH MOSTLY LIGHT WINDS.

OUTLOOK PERIOD...

WHILE FIRST UPPER VORTEX STALLS OVER MID OCEAN DAY 3..A SECOND 
UPPER TROUGH MOVES OFF THE SE COAST TO NEAR 72W. STRONG UPPER 
RIDGE BEGINS TO BUILD OVER MID CONTINENT. ATLC COLD FRONT MOVES 
TO E OF 50W. OLD POLAR AIRMASS 1024 MB DRIFTS E TO NEAR 30N65W. 
GULF COLD FRONT WEAKENS TO A TROUGH E OF FL DAY 3 WITH WEAK 1021 
MB HIGH FOLLOWING OVER NE GULF. CARIB WINDS REMAIN ELY 20 KT S 
OF 18N. 

FIRST UPPER VORTEX FINALLY EXITING THE AREA WHILE THE SECOND ONE 
LIFTS NE ALONG 70W DAY 4. OVERALL UPPER FLOW BECOMING MORE ZONAL 
WITH TIME. ON THE SURFACE THE PRESSURE PATTERN BECOME MORE E/W. 
THE OLD POLAR AIRMASS 1022 MB DRIFTS TO NEAR 30N60W WITH A RIDGE 
BACK OVER THE NRN GULF. SOME RETURN FLOW INCREASING W OF 90W DAY 
4 TO 20 KT. CARIB WINDS WEAKEN SOME. OLD FRONTAL TROUGH MOVES TO 
NEAR 70W.

WHATS LEFT OF THE E COAST UPPER TROUGH SEPARATES DAY 5 WITH THE 
SRN BRANCH MOVING E TO NEAR 60W. W OF 70W THE UPPER FLOW BECOMES 
WLY BUT A NEW SURGE OF COLD AIR IS EVIDENT OVER THE UPPER PLAINS 
WHICH IS EXPECTED TO CARVE OUT A NEW TROUGH OVER THE ERN US. ON 
THE SURFACE THE OLD AIRMASS MOVES TO NEAR 33N53W AT 1024 MB WITH 
AN AXIS BACK ACROSS CENTRAL FL. WINDS N OF 20N MOSTLY LIGHT 
WHILE S OF 20N LIGHT TO MODERATE.  

WARNINGS...

ATLANTIC...
NONE.

CARIBBEAN...
NONE.

GULF OF MEXICO...
NONE.

FORECASTER RRG