000
AGXX40 KNHC 130640
MIMATS

MARINE WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
130 AM EST SUN JAN 13 2008
 
MARINE WEATHER DISCUSSION FOR GULF OF MEXICO...CARIBBEAN SEA AND 
SOUTHWEST NORTH ATLC S OF 31N W OF 55W.

PAIR OF MODERATE SHORTWAVES IN PHASE OVER THE MS VALLEY TONIGHT 
MOVING E TIGHTENING THE GRADIENT AT MID LEVELS OVER THE GULF AND 
SE CONUS. OLD CUTOFF LOW OVER ATLC WATERS OPENING UP AND LIFTING 
NE IN RESPONSE TO THE STRONG SWLY MID LEVEL FLOW. ON THE SURFACE 
TONIGHT A COLD FRONT HAS MOVED OFF THE TX COAST WITH WINDS NLY 
20 KT. REMAINDER OF GULF WITH LIGHT WINDS. MODERATE WINDS OVER S 
CENTRAL CARIB. WEAK ATLC LOW NEAR 28N60W MOVING N. ATLC RIDGE 
OVER MID OCEAN WITH 20 TO 25 KT E OF 50W. 

LATER DAY 1 STRONG SHORTWAVE MOVING ENE OVER TN VALLEY WITH 
SUBTROPIC JET OVER GULF. MID LEVEL RIDGES OVER CARIB AND CENTRAL 
ATLC. ON THE SURFACE LATER DAY 1 GULF COLD FRONT MOVES SE TO E 
CENTRAL PORTION WITH NLY WINDS TO 20 KT. FRONT MOVES OFF NE FL 
COAST WITH SLY WINDS TO 20 KT. OLD LOW OVER ATLC WITH MOSTLY 
LIGHT WINDS. LITTLE CHANGE ELSEWHERE. 

FOR DAY 2 UPPER PATTERN PROGRESSIVE WITH STRONG TROUGH OVER NE 
CONUS SHIFTING EWD. STRONG ZONAL FLOW OVER GULF AND ATLC W OF 
70W. ON THE SURFACE DAY 2 COLD FRONT MOVES TO CENTRAL BAHAMAS 
WITH 20 KT WINDS. MODERATE WINDS OVER ENTIRE GULF AS WELL AS 
MOST OF CARIB. ATLC TRADES 20 KT E OF 45W.

OUTLOOK PERIOD... 

FOR DAY 3 SPLIT FLOW ALOFT SETTING UP RIDGE BUILDING RAPIDLY 
OVER N CENTRAL PLAINS BEHIND EXITING STRONG SHORTWAVE. SRN 
BRANCH BECOMES MORE WSWLY WITH EMBEDDED SHORTWAVE OVER MX. ON 
THE SURFACE DAY 3 GFS MODEL SHOWS CYCLOGENESIS OVER SW GULF IN 
RESPONSE TO APPROACHING SHORTWAVE. COLD FRONT MOVES EWD MAINLY N 
OF 25N OVER CENTRAL ATLC WITH WINDS TO 20 KT. GULF WINDS 
INCREASE TO 20 TO 30 KT SW SECTION. 

FOR DAY 4 SHORTWAVE IN SRN BRANCH MOVES ENE OVER NW GULF BUT 
WEAKENING AS RIDGE BUILDS ALONG 80W IN RESPONSE TO LARGE STRONG 
SHORTWAVE DROPPING SE INTO NRN AND CENTRAL PLAINS. ON THE 
SURFACE DAY 4 LOW PRES DEVELOPS OVER CENTRAL GULF. GFS MODEL 
SHOWS WINDS TO 25 KT OVER MOST SECTIONS. WIND MAINLY PRODUCT OF 
GRADIENT TIGHTENING DUE TO 1025 MB POLAR HIGH MOVING E OVER SE 
CONUS..THEREFORE WINDS LOOK REASONABLE N AND NE GULF BUT MAY BE 
OVERDONE W AND SW SECTIONS. SW AND W WINDS INCREASE OVER ATLC N 
OF 29N BETWEEN 50W AND 70W WITH LOWERING PRES N OF AREA. 

FOR DAY 5 SHORTWAVE OVER GULF CONTINUES WEAKENING AS IT LIFTS NE 
OFF SE COAST. STRONG UPPER TROUGH IN NRN BRANCH MOVES E TOWARD 
OH VALLEY. ON THE SURFACE DAY 5 GFS MODEL CONTINUES TO STRENGTH 
LOW AS IT MOVES NE TOWARD SE CONUS COAST. NOT SURE SURFACE LOW 
CAN STRENGTHEN LIKE THIS GIVEN WEAKENING SHORTWAVE BUT SUBTROPIC 
JET OVER NRN GULF PROBABLY WHAT GFS USES FOR ENERGY TO DEVELOP 
SURFACE LOW. GFS THUS SHOWS GALE CONDITIONS N OF 28N W OF 74W 
WITH DEPARTING LOW WHICH MAY BE SLIGHTLY HIGH EVEN WITH A 1004 
MB LOW CENTER. GULF WINDS NLY 20 KT LOOKS REASONABLE GIVEN A 
1026 MB HIGH OVER TX. FRONT OVER ATLC E OF 52W WITH WINDS TO 20 
KT. CARIB WINDS TO 20 KT E OF 77W.  

WARNINGS...
ATLANTIC...
NONE.

CARIBBEAN...
GALE WARNING...

GULF OF MEXICO...
NONE.

FORECASTER RRG