[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 311144
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
705 AM EST THR DEC 31 2009

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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1130 UTC.

...THE ITCZ...

THE ITCZ AXIS IS ANALYZED FROM WEST AFRICA...OVER THE SOUTH
COAST OF SIERRA LEONE NEAR 7N12W...THROUGH 5.5N20W 4N30W
3.5N40W...TO NORTHEAST BRAZIL NEAR THE CITY OF BELEM AT 1S45W.
THE ITCZ HAS BEEN RELATIVELY CALM OVER THE PAST 6 HOURS. ONLY
SCATTERED WEAK CONVECTION IS OBSERVED WITHIN 150 NM OF THE ITCZ
BETWEEN 17W AND 30W.

...DISCUSSION...

THE GULF OF MEXICO...

A 1016 MB LOW IS CENTERED OVER THE WESTERN COAST OF ALABAMA NEAR
30N87W. A COLD FRONT EXTENDS SOUTHWEST FROM THE LOW CENTER ALONG
25N90W 23N92W 22N94W. THIS FRONT IS SLOWLY MOVING EASTWARD INTO
THE EASTERN BASIN. SHIP AND BUOY OBSERVATION SHOW NORTHWEST
WINDS 5 TO 10 KTS BEHIND THE FRONT. TO THE EAST OF THE FRONT
NORTH OF 23N...OBSERVATIONS SHOW SOUTHEAST WINDS 10 TO 20 KTS. A
WARM FRONT IS ANALYZED EXTENDING SOUTHEAST FROM THE LOW CENTER
ALONG 29N85W 28N83W. THIS LOW PRESSURE SYSTEM WILL CONTINUE A
NORTHEAST TRAJECTORY OVER THE NEXT 24 HOURS. IN THE UPPER LEVELS
OF THE ATMOSPHERE...A WIDE TROUGH COVERING MUCH OF THE CENTRAL
CONTINENTAL US IS PRODUCING LIGHT SOUTHWEST UPPER LEVEL FLOW
OVER THE ENTIRE GULF. WATER VAPOR IMAGERY SHOWS THIS UPPER LEVEL
FLOW TRANSPORTING MOISTURE FROM THE EASTERN TROPICAL PACIFIC
INTO THE GULF OF MEXICO TO SUPPORT CONVECTION IN THIS REGION.
RADAR IMAGERY SHOWS A BROAD LINE OF WEAK TO MODERATE SHOWERS
MOVING ALONG THE NORTHEAST GULF COAST. THIS SHOWERS ARE MOVING
PARALLEL TO THE 30N LINE THROUGH THE FLORIDA PANHANDLE.
PRECIPITATION WILL MOVE ACROSS NORTHERN FLORIDA INTO THE WESTERN
ATLANTIC OCEAN OVER THE NEXT 24 TO 36 HOURS.

THE CARIBBEAN SEA...

UPPER LEVEL HIGH PRESSURE CONTINUES TO DOMINATE MOST OF THE
CARIBBEAN BASIN...BRINGING STRONG SUBSIDENCE OF AIR ALOFT AND
SUPPRESSING DEEP CONVECTION ACROSS THE BASIN. NEVERTHELESS...THE
SOUTH END TIP OF A ATLANTIC COLD FRONT IS PASSING 50 NM SOUTH OF
THE ISLAND OF PUERTO RICO TO NEAR 15N70W. THUS...WEAK CONVECTION
IS OBSERVED NORTH OF 15N BETWEEN 62W AND 72W. DOPPLER RADAR
IMAGERY SHOWS AN AREA OF WEAK ISOLATED SHOWERS MOVING IN
SOUTHWEST DIRECTION 30 NM SOUTH OF PUERTO RICO. SATELLITE
IMAGERY INDICATES THESE SHOWERS MAY EXTEND SOUTHWESTWARD TO
15N70W. SHIP AND BUOY OBSERVATIONS SHOW NORTHEAST WINDS 10 TO 20
KTS BEHIND OF THE FRONTAL BOUNDARY. ELSEWHERE...EASTERLY WINDS
10 TO 20 KTS ARE REPORTED ACROSS THE BASIN. THE ACTIVITY IN THE
NORTHEAST BASIN WILL LESSEN AS THE FRONT SLOWLY MOVES OUT OF THE
AREA. HIGH PRESSURE WILL KEEP DEEP CONVECTION FROM HAPPENING
OVER THE CARIBBEAN. THEREFORE...EXPECT LITTLE CHANGE OVER THE
NEXT 24 HOURS.

THE ATLANTIC OCEAN...

AN UPPER LEVEL RIDGE IS OVER THE WESTERN ATLANTIC...MOVING ALONG
A SURFACE HIGH PRESSURE OF 1030 MB INTO THE WESTERN BASIN. THUS
LIGHT SURFACE ANTICYCLONIC FLOW IS OBSERVED IN THIS REGION. A
SHARP UPPER LEVEL TROUGH IS MOVING ACROSS THE CENTRAL ATLANTIC.
THE TAIL END OF A COLD FRONT ENTERS THE CENTRAL ATLANTIC NEAR
30N40W AND EXTENDS SOUTHWEST ALONG 21N50W 18N60W TO SOUTH OF THE
ISLAND OF PUERTO RICO. BROKEN COLD AIR STRATOCUMULUS CLOUDS ARE
WEST OF THE FRONT TO 70W. WEAK CONVECTION IS OCCURRING WITHIN
120 NM EAST OF THE COLD FRONT. GALE FORCE WINDS ARE EXPECTED TO
DEVELOP OVER THE NEXT 24 TO 36 HOURS WITHIN 300 NM WEST OF THE
COLD FRONT NORTH OF 29N. AN UPPER LEVEL RIDGE OVER THE EASTERN
ATLANTIC IS FEEDING A 1022 MB HIGH NEAR 30N26W. EXPECT OVER THE
NEXT 24 TO 36 HOURS FOR THE COLD FRONT TO MOVE EAST INTO THE
EASTERN ATLANTIC NEAR 35W WITH CONVECTION.

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

$$

GARCIA




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