000
AGXX40 KNHC 290515
MIMATS

MARINE WEATHER DISCUSSION   
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 
130 AM EDT SAT APR 29 2006

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

A LARGE UPPER TROUGH OVER THE SW ATLC TONIGHT RECEIVING A NEW 
SURGE OF COLD AIR ALOFT FROM THE NRN BRANCH OF THE WESTERLIES. 
THIS IS LOWERING MID LEVEL HEIGHTS OFF THE SE COAST. AN UPPER 
RIDGE BULGES NWD FROM THE GULF TO THE ERN GREATLAKES. A NEW 
UPPER TROUGH IS WORKING E OUT OF THE SRN ROCKIES TONIGHT. ON THE 
SURFACE A DEVELOPING STORM WAS LOCATED NEAR 33N68W 1006 MB. THE 
SYSTEM WAS DRIFTING SE. WILL PROBABLY DROP GALE WARNING S OF 31N 
ON W SIDE OF LOW BUT PUT GALE WRNG ON SE QUADRANT N OF 28N 
BETWEEN 58W AND 63W BEGINNING 00Z 30 APR AND ENDING 06Z 01 MAY. 
RETURN FLOW HAS INCREASED OVER THE WRN GULF TONIGHT WITH SE 
WINDS 25  KT W OF 90W. 

STRONG JET STREAK FORECAST TO DIG SW ATLC TROUGH DAY 1 WILL 
LOWER MID LEVEL HEIGHTS FURTHER S OF 31N. UPPER TROUGH MOVING 
INTO SRN PLAINS DAY 1 AS UPPER RIDGE SHIFTS EWD TO 85W. GFS 
MODEL WEAKENS SURFACE LOW NEAR 31N67W 1008 MB DAY 1. NOT SURE 
WHY..POSSIBLY NEW DEVELOPMENT FURTHER N. STRENGTHENING RIDGE 
ALONG 80W WILL KEEP WINDS BRISK W OF 70W TO 95W. WEAK FRONT 
MOVES OFF TX COAST DAY 1. CARIB WINDS MOSTLY LIGHT TO MODERATE 
EXCEPT FOR NW PORTION WHERE NE AND E WINDS 20 KT. 

GFS MODEL SHOWS UPPER TROUGH CLOSING OFF NEAR 30N67W DAY 2. 
UPPER TROUGH OVER SRN PLAINS BEGINS LIFTING NE TOWARD MIDWEST. 
GFS CRANKS UP A 1001 MB LOW NEAR 33N67W. POSSIBLE SE WINDS TO 
GALE FORCE AHEAD OF COLD FRONT N OF 29N BETWEEN 55W AND 60W. ON 
W SIDE OF LOW SURFACE RIDGE ALONG 80W WEAKENS AND GRADIENT 
DOESN'T SUPPORT GALE CONDITION S OF 31N. GULF FRONT FIZZLES OUT 
DAY 2 OVER W CENTRAL PORTION. STILL BRISK WINDS OVER ERN GULF 
AND NW CARIB. ATLC RIDGE CENTERED OVER MID OCEAN WITH GUSTY 
WINDS E OF 60W.

OUTLOOK PERIOD...

FIRST DAY OF MAY FINDS UPPER TROUGH BECOMING NEGATIVELY TILTED 
ALONG 60W. UPPER TROUGH OVER MID WEST SHIFTING NWD AS UPPER FLOW 
S OF 40N W OF 80W BECOMES MORE ZONAL. SURFACE LOW OVER SW ATLC 
BEGINS TO LIFT NE TO NEAR 32N65W 1003 MB. WINDS OVER OUR AREA 
MOSTLY 25 KT IN SE QUADRANT. RIDGE ALONG 80W WEAKENING DAY 3 AND 
WINDS DECREASE OVER NW CARIB AND ERN GULF. SOME RETURN FLOW 
SETTING UP W OF 90W TO 20 KT. 

UPPER TROUGH OVER SW ATLC LIFTING NWD STILL TRAPPING COLD AIR 
POCKETS MOVING SE IN THE NRN BRANCH. ONE OF WHICH MOVES OFF THE 
N CAR COAST DAY 4. SURFACE LOW MOVES WELL N OF AREA DAY 4 WITH 
ATLC WINDS DECREASING BELOW 20 KT. WEAKENING RIDGE OVER FL 
DRIFTING SE. GULF AND CARIB WINDS MOSTLY LIGHT TO MODERATE. ATLC 
RIDGE CENTERED OVER MID OCEAN DAY 4 WITH MODERATE TRADES E OF 
60W.

SHORTWAVES MOVING RAPIDLY EWD JUST N OF 30N IN THE STRONG ZONAL 
FLOW ALOFT DAY 5. WEATHER PATTERN WEAKENING DAY 5 AS RIDGE OF 
HIGH PRES COVERS ERN GULF AND SW ATLC W OF 65W. SOME RETURN FLOW 
TO 20 KT W OF 95W AS SURFACE PRESSURES LOWER OVER SRN PLAINS. 
CARIB WINDS MOSTLY NE TO E LIGHT TO MODERATE. TRADES TO 20 KT 
CONFINED TO S OF 20N E OF 55W DAY 5. 

WARNINGS...

ATLANTIC...
GALE WARNING...N OF 28N BETWEEN 58W AND 63W BEGINNING 00Z 30 APR 
AND ENDING 06Z 01 MAY.

CARIBBEAN...
NONE.

GULF OF MEXICO...
NONE.

FORECASTER RRG