000
AGXX40 KNHC 280448
MIMATS

MARINE WEATHER DISCUSSION   
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 
130 AM EDT FRI APR 28 2006

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

THE MAIN ATTRACTION TONIGHT IS A STRONG VORTICITY CENTER 
ASSOCIATED WITH A SHORTWAVE MOVING OFF THE SE U.S. COAST. THE 
GFS APPEARS TO HAVE A GOOD POSITION AND INTENSITY AT 06Z WITH 
THE WATER VAPOR IMAGERY. AN UPPER RIDGE APPEARS TO BE AMPLIFYING 
A BIT ALONG 95W. ON THE SURFACE A COLD FRONT HAS MOVED OVER THE 
NW BAHAMAS TONIGHT WITH WINDS TO 20 KT. THE LARGE ATLC RIDGE IS 
MAINLY E OF 65W AND THE GRADIENT OVER THE CARIB IS WEAK.

FOR DAY 1 THE STRONG VORT CENTER IS FORECAST TO MOVE ESE TO NEAR 
32N72W WITH A SECOND SHORTWAVE DROPPING SE BEHIND IT OVER THE NE 
U.S.  UPPER RIDGE STRENGTHENS ALONG 90W IN ADVANCE OF THE NEXT 
STRONG SYSTEM MOVING E OVER THE SRN ROCKIES. SURFACE LOW 1008 MB 
NEAR 33N71W WITH 25 TO 30 KT DROPPING S TO 31N AND A GALE 
CONDITION TO 31N.  WILL HOLD OFF INITIALLY ON GALES S OF 31N. 
RETURN FLOW SETTING UP W OF 90W AS PRESSURES LOWER OVER THE SRN 
PLAINS. 

GFS SHOWS COLD AIR WITH SECOND SHORTWAVE DROPS RAPIDLY INTO THE 
VORT CENTER AND AMPLIFIES THE SHORTWAVE ALONG 70W DAY 2 AND 
SENDS IT SSE INTO OUR AREA. GFS RESPONDS CORRECTLY WITH LOWERING 
PRESSURE IN SURFACE LOW TO 1006 MB WITH CENTER MOVING SE TO NEAR 
30N68W. 25 TO 35 KT WINDS MOVE S TO 29N IN W QUADRANT THEREFORE 
WILL POST GALE WARNING N OF 29N WITHIN 300 NM W OF CENTER FOR 
DAY 2. FAIRLY STRONG RIDGE ALONG 80W WILL KEEP WINDS BRISK W OF 
70W AND OVER GULF AND NW CARIB. WEAK TROUGH MOVES TO TX COAST 
DAY 2. 

OUTLOOK PERIOD...

CIRCULATION CLOSES OFF DAY 3 WITH CENTER NEAR 28N67W. NEXT LARGE 
UPPER VORTEX MOVES INTO CENTRAL PLAINS. UPPER RIDGE OVER GULF 
SHIFTS E TO ALONG 83W. 1005 MB LOW NEAR 29N67W WITH NO GALE 
FORCE WINDS ACCORDING TO GFS MODEL. REASON APPEARS TO BE 
WEAKENING OF RIDGE ALONG 80W DAY 3. WEAK TROUGH ALONG N GULF 
COAST FIZZLES OUT. WINDS E OF 90W SE 20 KT ACCORDING TO GFS. NW 
CARIB WINDS NE TO 20 KT. ATLC RIDGE MAINLY E OF 60W AND N OF 
20N.  

SHORTWAVE BEGINS TO LIFT NE ALONG 60W DAY 4 AS UPPER FLOW 
BECOMES MORE WESTERLY. LOOKS LIKE NRN BRANCH WEAKENING AS 
SOURCES OF COLD AIR WEAKEN WITH SPRING TIME WARMING. FIRST DAY 
OF MAY FINDS SURFACE FEATURES WEAKENING AND WINDS DECREASING. 
1009 MB LOW NEAR 30N64W WITH GUSTY SLY WINDS MAINLY E OF OF 
CENTER AGAINST ATLC RIDGE.

STRONG ZONAL FLOW S OF 40N OVER CENTRAL U.S. DAY 5 WORKS IT'S 
WAY E TO 50W. WHATS LEFT OF COLD AIR ALOFT RELEGATED TO 
GREATLAKES..NE U.S. AND OVER NW ATLC. SURFACE PATTERN BEGINS TO 
BE DOMINATED BY HIGH PRESSURE DAY 5. OLD ATLC RIDGE 1025 MB OVER 
MID OCEAN AND WEAKER HIGH 1020 MB MOVING OFF SE COAST. WEAK 
FRONTAL TROUGH ALONG 60W. MOST AREAS LIGHT TO MODERATE WINDS 
WITH SOME RETURN FLOW SETTING UP W OF 90W.

WARNINGS...

ATLANTIC...
NONE.

CARIBBEAN...
NONE.

GULF OF MEXICO...
NONE.

FORECASTER RRG