000
AXNT20 KNHC 182350
TWDAT 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL  
705 PM EST THU FEB 18 2010

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...METEOROLOGICAL ANALYSIS...WEATHER 
OBSERVATIONS...AND RADAR.

BASED ON 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
2345 UTC.

...ITCZ...

FROM THE NORTHERN COAST OF LIBERIA NEAR 6N11W...WESTWARD ALONG 
3.5N20W 1N30W 1N40W EQ50W. SCATTERED MODERATE CONVECTION IS 
WITHIN 40 NM EITHER SIDE OF THE AXIS BETWEEN 13W AND 27W.

...DISCUSSION...

GULF OF MEXICO...
UPPER LEVEL QUASI-FLAT RIDGE OVER THE GULF OF MEXICO AND MOST OF 
CENTRAL CONUS CONTINUES TO SUPPORT A 1025 MB SURFACE HIGH NEAR 
CENTRAL MISSISSIPPI. THIS FEATURE IS BRINGING STRONG SUBSIDENCE 
AND DRY AIR ACROSS THE REGION. HOWEVER...AN UPPER LEVEL MOISTURE 
PLUME FROM THE EAST TROPICAL PACIFIC IS STREAMING ACROSS MEXICO 
AND INTO THE GULF...SEEN AS HIGH CLOUDS. FURTHERMORE...WATER 
VAPOR IMAGERY SHOWS A SHARP MID LEVEL SHORTWAVE ENTERING THE FAR 
WESTERN BASIN IS PRODUCING AN AREA OF CONVERGENCE IN THIS AREA. 
DOPPLER RADAR IMAGERY SHOWS WEAK TO MODERATE SHOWERS WEST OF 94W 
NORTH OF 23N...MOVING NORTHEASTWARD AT ABOUT 15 KT. ELSEWHERE 
EAST OF 94W...MARINE OBSERVATIONS ACROSS THE BASIN SHOW 
ANTI-CYCLONIC FLOW 10 TO 20 KT OVER THE ENTIRE BASIN. COMPUTER 
MODELS INDICATE AT A SURFACE TROUGH DEVELOPING ALONG THE WESTERN 
GULF COAST OVER THE NEXT 24 HOURS...BRINGING CONVECTION TO THIS 
REGION...WHILE THE SURFACE HIGH MOVING EASTWARD TO THE NORTHEAST 
BASIN...KEEPING FAIR WEATHER ELSEWHERE EAST OF THE TROUGH.

CARIBBEAN SEA...
UPPER LEVEL RIDGE OF HIGH PRESSURE COVERS MOST OF THE CENTRAL 
AND EASTERN CARIBBEAN SEA. THEREFORE...MOSTLY FAIR WEATHER WITH 
MODERATE TO FRESH TRADEWINDS ARE NOTED EAST OF 77W. HOWEVER...A 
REMNANT LINE OF SHOWERS FROM A STATIONARY FRONT EXTENDS FROM THE 
WINDWARD PASSAGE TO THE SOUTHWEST BASIN ALONG 19N75W 16N77W 
12N81W. A FEW SCATTER SHOWERS ARE WITHIN 50 NM ON EITHER SIDE OF 
THE LINE. NORTHERLY WINDS 5 TO 15 KT ARE ALSO NOTED TO THE WEST 
OF THE LINE. ALSO...AN UPPER LEVEL MOISTURE PLUME FROM THE EAST 
TROPICAL PACIFIC IS STREAMING ACROSS CENTRAL AMERICA INTO THE 
FAR NORTHWEST BASIN...SEEN AS HIGH CLOUDS MOSTLY NORTH OF 16N 
WEST OF 78W. LOOK FOR THIS LINE TO CONTINUE TO WEAKEN AND 
DISSIPATE WHILE SLOWLY SHIFTING EASTWARD INTO THE CENTRAL BASIN 
OVER THE NEXT 24 HOURS.

ATLANTIC OCEAN.
AN UPPER LEVEL LONGWAVE TROUGH IS ACROSS THE WESTERN NORTH 
ATLANTIC MAINLY NORTH OF 29N. THIS FEATURE SUPPORTS A COLD FRONT 
THAT MOVES ACROSS THE CENTRAL ATLANTIC REGION ALONG 29N47W 
24N56W 21N64W...BECOMING STATIONARY FROM 21N64W TO NORTH CENTRAL 
DOMINICAN REPUBLIC. OVERCAST LOW CLOUDS WITH SCATTERED SHOWERS 
ARE WITHIN 70 NM ON EITHER SIDE OF THE COLD FRONT...AND WITHIN 
50 NM ON EITHER SIDE OF THE STATIONARY FRONT. HOWEVER...A 
SURFACE 1018 MB HIGH PRESSURE EAST OF THE FRONT NEAR 22N29W IS 
PREVENTING THE FRONT FROM ADVANCING ANY FASTER. 
ALSO...ANTI-CYCLONIC FLOW AHEAD OF THE FRONT HAVE PUSHED PART OF 
THE FRONT NORTHWARD...TRANSFORMING IT INTO A WARM FRONT NORTH OF 
29N. THIS SURFACE HIGH IS SUPPORTED BY A BROAD UPPER LEVEL RIDGE 
OVER THE CENTRAL ATLANTIC BRINGING SUBSIDENT AIR ALOFT AND 
SUPPRESSING ANY DEEP CONVECTION ACROSS THE CENTRAL AND EASTERN 
ATLANTIC EAST OF 50W. THEREFORE...LOOK FOR THIS FRONT TO SLOWLY 
WEAKEN AS IT CONTINUES TO MOVE EASTWARD ACROSS THE CENTRAL 
ATLANTIC.

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

$$

GARCIA