[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 281746
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
105 PM EST SAT JAN 28 2012

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
1730 UTC.

...THE ITCZ/THE MONSOON TROUGH...

MOST OF THE MONSOON TROUGH EXTENDS ACROSS AFRICA THIS AFTERNOON...
WITH A SMALL PORTION OF IT EXTENDING INTO THE E TROPICAL ATLC ALONG
THE COAST OF SIERRA LEONE NEAR 8N13W TO 8N15W...WHERE THE ITCZ AXIS
CONTINUES ALONG 3N30W TO INLAND OVER BRAZIL NEAR 1N50W. CLUSTERS OF
SCATTERED MODERATE CONVECTION ARE WITHIN 100 NM ON EITHER SIDE OF
THE ITCZ W OF 23W.

...DISCUSSION...

GULF OF MEXICO...
BROAD UPPER CYCLONIC FLOW COVERS THE CONUS EXTENDING S TO THE GULF
OF MEXICO...WITH STRONG SUBSIDENCE AND DRY STABLE AIR OVER THE NW
BASIN. THIS FEATURE SUPPORTS A NEAR STATIONARY FRONTAL BOUNDARY JUST
S OF THE FLORIDA KEYS TO ALONG THE NW COASTAL WATERS OF CUBA THROUGH
THE YUCATAN CHANNEL...BECOMING WEAK AS IT ENTERS THE NE YUCATAN
PENINSULA. DOPPLER RADAR IMAGERY INDICATES SCATTERED SHOWERS WITH A
FEW ISOLATED THUNDERSTORMS OCCURRING WITHIN 75 NM NW OF THE
BOUNDARY. WEAK SURFACE RIDGING ANCHORED IN THE SE CONUS ALONG WITH
THE DRY/SUBSIDENT UPPER ATMOSPHERE IS KEEPING THE REMAINDER OF THE
GULF WITH MOSTLY CLEAR SKIES THIS EARLY AFTERNOON. THE STATIONARY
FRONT WILL SLOWLY DISSIPATE THROUGH EARLY NEXT WEEK. THE WEAK
RIDGING WILL BE REPLACED BY STRONGER HIGH PRESSURE THAT BEGINS TO
BUILD ACROSS THE AREA LATER THIS AFTERNOON. THIS HIGH PRESSURE AREA
WILL THEN CONTINUE TO BUILD E ACROSS THE GULF INTO EARLY NEXT WEEK.
SOUTHERLY RETURN FLOW THEN SETS UP OVER THE NW GULF LATE MON THROUGH
WED.

CARIBBEAN SEA...
BROAD UPPER RIDGE CENTERED JUST N OF PUERTO RICO IS GIVING THE
CARIBBEAN SW TO W FLOW ALOFT. WATER VAPOR IMAGERY SHOWS STRONG
SUBSIDENCE WITH DRY STABLE AIR ACROSS THE BASIN WITH THE EXCEPTION
OF THE FAR NW AREA WHERE THE NEAR STATIONARY FRONT OVER THE SE GULF
OF MEXICO EXTENDS THROUGH THE YUCATAN CHANNEL TO INLAND OVER THE
YUCATAN PENINSULA...WITH POSSIBLE ISOLATED SHOWERS WITHIN 30 NM SE
OF THE FRONT. MARINE OBSERVATIONS AND VISIBLE SATELLITE IMAGERY SHOW
GENTLE TO MODERATE EASTERLY TRADE WINDS WITH A FEW POCKETS LOW LEVEL
MOISTURE AND POSSIBLE ISOLATED WEAK ACROSS THE AREA. OTHERWISE...THE
REMAINDER OF THE CARIBBEAN IS UNDER FAIR WEATHER THIS AFTERNOON. THE
WEAK STATIONARY FRONT WILL SLOWLY DISSIPATE THROUGH TUE. STRONG HIGH
PRESSURE WILL BUILD SE ACROSS MUCH OF THE N CARIBBEAN THROUGH WED.

ATLANTIC OCEAN...
THE BROAD CYCLONIC FLOW ALOFT THAT COVERS THE CONUS SUPPORTS AN
UPPER LONGWAVE MOVING OFF THE ERN CONUS SEABOARD. THIS FEATURE
FURTHER SUPPORTS A NEARLY STATIONARY FRONT THAT ENTERS THE
DISCUSSION AREA NEAR 32N70W CONTINUING SW ACROSS THE NW BAHAMAS NEAR
26N78W INTO THE STRAITS OF FLORIDA AND THE FAR SE GULF OF MEXICO.
SCATTERED SHOWERS AND POSSIBLE ISOLATED THUNDERSTORMS ARE WITHIN 30
NM ON EITHER SIDE OF THE FRONT N OF 25N E OF 80W. THE REMAINDER OF
THE W AND CENTRAL ATLC W OF 37W ARE DOMINATED BY A SURFACE RIDGE
ANCHORED BY A 1025 MB HIGH NEAR 28N57W...GIVING THE AREA FAIR
WEATHER THIS AFTERNOON. A NARROW UPPER TROUGH DIPS S OVER THE ERN
ATLC N OF 19N BETWEEN 30W-40W SUPPORTING A FRONTAL BOUNDARY THAT
EXTENDS INTO THE AREA AS A SURFACE TROUGH FROM 31N32W TO 20N31W
GENERATING CLUSTERS OF SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS
WITHIN 100 NM ON EITHER SIDE OF IT N OF 22N. A SURFACE RIDGE
DOMINATES THE FAR E ATLC ANCHORED BY A 1034 MB HIGH WELL N OF THE
DISCUSSION AREA. THE W ATLC FRONT WILL START TO MOVE SLOWLY EASTWARD
THROUGH EARLY SUN. STRONG HIGH PRESSURE WILL BEGIN TO BUILD E ACROSS
THE W ATLC ON SUN.

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

$$

GARCIA




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