000
AXNT20 KNHC 281743
TWDAT 

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
105 PM EST MON JAN 28 2013

TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL 
AMERICA...GULF OF MEXICO...CARIBBEAN SEA...NORTHERN 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY
THROUGH 1715 UTC.

...ITCZ/MONSOON TROUGH...

THE MONSOON TROUGH EXTENDS FROM THE PRIME MERIDIAN AT 6N ALONG 
3N7W 3N16W. THE ITCZ BEGINS AT 3N16W AND CONTINUES ALONG 2N27W 
6N43W 2N51W. WIDELY ISOLATED MODERATE CONVECTION IS ALONG THE 
AXIS BETWEEN 27W-36W.

...DISCUSSION...

THE GULF OF MEXICO...
SURFACE RIDGING DOMINATES THE GULF OF MEXICO TODAY AROUND A 1033 
MB HIGH CENTERED JUST OFFSHORE OF VIRGINIA. THIS PATTERN IS 
PROVIDING MAINLY SE TO S SURFACE WINDS RANGING FROM 10-20 KT. 
SKIES ARE MOSTLY CLEAR EXCEPT FOR A FEW ISOLATED SHOWERS NEAR A 
WEAK SURFACE TROUGH ANALYZED FROM 29N86W TO 25N88W. 
ALOFT...BROAD RIDGING COVERS THE ENTIRE EASTERN CONUS INCLUDING 
THE GULF SUPPORTING THE SURFACE RIDGE. LITTLE CHANGE IS EXPECTED 
OVER THE NEXT 24 HOURS...HOWEVER...A COLD FRONT IS EXPECTED TO 
MOVE INTO THE NW GULF LATE TUE/EARLY WED.

THE CARIBBEAN SEA...
DRY AIR ALOFT AROUND A BROAD UPPER RIDGE IS KEEPING FAIR 
CONDITIONS ACROSS MUCH OF THE CARIBBEAN TODAY. SOME LOW LEVEL 
MOISTURE IS HELPING SUPPORT A FEW AREAS OF ISOLATED SHOWERS 
EMBEDDED WITHIN THE TRADEWIND FLOW PRESENT THROUGHOUT THE AREA. 
DUE TO A TIGHTENING PRESSURE GRADIENT BETWEEN THE HIGH PRESSURE 
CENTER TO THE NORTH AND LOWER PRESSURES OVER COLOMBIA...THE 
TRADE WINDS REACH 15-20 KT ACROSS MUCH OF THE AREA WITH 25 KT 
WINDS NEAR THE COAST OF COLOMBIA EXPECTED TO INCREASE TO GALE 
FORCE LATER TONIGHT. LITTLE CHANGE IS EXPECTED OTHERWISE.

THE ATLANTIC OCEAN...
SURFACE HIGH PRESSURE IS DOMINATING THE WEST ATLC ANCHORED BY A 
1033 MB HIGH NEAR 37N75W. THE HIGH IS SUPPORTED BY AN UPPER 
LEVEL RIDGE COVERING THE EASTERN CONUS AND WEST ATLC. BROAD 
UPPER TROUGHING IS TO THE EAST ALONG 50W SUPPORTING A PAIR OF 
FRONTAL BOUNDARIES THAT ENTER THE AREA IN THE CENTRAL ATLC AND 
WRAP AROUND THE SOUTHERN PORTION OF THE SURFACE RIDGE. FARTHEST 
EAST OF THE TWO...A DISSIPATING COLD FRONT ENTERS FROM 32N42W TO 
23N59W WHERE IT TRANSITIONS INTO A SHEAR AXIS TO 20N70W. 
ISOLATED SHOWERS ARE WITHIN 180 NM EAST OF THE AXIS. A COLD 
FRONT IS TO THE WEST ENTERING NEAR 32N45W CONTINUING ALONG 
26N58W 25N70W WHERE IT BECOMES DISSIPATING TO NEAR 27N80W. 
ISOLATED SHOWERS ARE WITHIN 85 NM AHEAD OF THE COLD FRONT WITH 
POSSIBLE ISOLATED SHOWERS ALONG THE DISSIPATING PORTION. ACROSS 
THE EASTERN ATLC...SURFACE RIDGING IS PRESENT ANCHORED BY A 1032 
MB HIGH OVER PORTUGAL...WHICH IS PROVIDING FAIR CONDITIONS 
ACROSS THE AREA. THE SYSTEM IS SUPPORTED ALOFT BY AN UPPER LEVEL 
RIDGE EXTENDING FROM 20N32W TO 47N10W. 

FOR ADDITIONAL INFORMATION PLEASE VISIT
HTTP://WWW.HURRICANES.GOV/MARINE

$$
WALTON