[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 011707
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT THU NOV 01 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 1645 UTC.

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

ONLY A SMALL PORTION OF THE MONSOON TROUGH EXTENDS OVER WATER
FROM THE COAST OF GUINEA AT 10N14W TO 9N18W. THE AXIS DOES NOT
CONTINUE ANY FURTHER WEST DUE TO A WEAK SURFACE RIDGE EXTENDING
FROM NW AFRICA INTO THE TROPICAL REGION. HOWEVER...AN AREA OF
SCATTERED MODERATE CONVECTION IS FROM 5N-13N BETWEEN 26W-33W.
SIMILAR ACTIVITY IS FROM 9N-11N BETWEEN 35W-41W.

...DISCUSSION...

THE GULF OF MEXICO...
A BROAD UPPER TROUGH CONTINUES TO COVER THE GULF OF MEXICO TODAY
EXTENDING FROM THE NE CONUS. DRY AIR IS WRAPPING AROUND THE
UPPER TROUGH HELPING PROVIDE MOSTLY CLEAR SKIES ACROSS THE AREA.
A WEAK COLD FRONT EXTENDS ACROSS FLORIDA INTO THE EASTERN GULF
ALONG 27N80W TO 28N89W. ISOLATED SHOWERS ARE WITHIN 60 NM SOUTH
OF THE AXIS. A SURFACE TROUGH IS TO THE NORTH OF THE FRONT
DEPICTING ANOTHER WIND SHIFT AROUND THE LARGE LOW PRESSURE
SYSTEM TO THE NORTH. SURFACE RIDGING COVERS THE REMAINDER OF THE
BASIN CENTERED AROUND A 1019 MB HIGH NEAR 24N88W. THE ONLY OTHER
ACTIVE WEATHER IN THE AREA IS A PATCH OF SHOWERS/THUNDERSTORMS
NEAR THE SOUTHERN TIP OF TEXAS FROM 25N-26N BETWEEN 95W-98W. THE
FRONT WILL LIKELY WEAKEN ACROSS THE GULF WHILE THE TROUGH TO THE
NORTH WILL MOVE SOUTH. SURFACE RIDGING IS EXPECTED TO REMAIN
ELSEWHERE ACROSS THE BASIN FOR THE NEXT 24 HOURS.

THE CARIBBEAN SEA...
MODERATELY MOIST SOUTHWESTERLY FLOW ALOFT COVERS THE WESTERN
CARIBBEAN BETWEEN AN UPPER LEVEL TROUGH COVERING THE EASTERN
CONUS AND GULF OF MEXICO AND AN UPPER LEVEL RIDGE ACROSS THE
CENTRAL ATLC. A SURFACE TROUGH STILL REMAINS FROM JAMAICA TO THE
SW CARIBBEAN ALONG 18N77W TO 11N78W. SCATTERED SHOWERS/ISOLATED
THUNDERSTORMS ARE WITHIN 120 NM WEST OF THE AXIS AS WELL AS FROM
JAMAICA TO EASTERN CUBA. SIMILAR ACTIVITY COVERS THE EXTREME SW
CARIBBEAN S OF 12N BETWEEN 76W-84W ENHANCED BY THE MONSOON
TROUGH WHICH EXTENDS FROM SOUTHERN COSTA RICA TO NORTHERN
COLOMBIA. THE EASTERN CARIBBEAN IS EXPERIENCING MOSTLY FAIR
WEATHER DUE TO DRY AIR ALOFT MOVING OVER THE AREA AROUND THE
UPPER RIDGE OVER THE CENTRAL ATLC. POSSIBLE ISOLATED SHOWERS ARE
EMBEDDED WITHIN 10-15 KT TRADEWIND FLOW. SOME STRONG WINDS UP TO
20 KT ARE OFF THE COAST OF COLOMBIA. MOIST CONDITIONS WILL
REMAIN ACROSS THE SW CARIBBEAN AND SPREAD WEST AS THE SURFACE
TROUGH IN THE THAT AREA DRIFTS WESTWARD.

THE ATLANTIC OCEAN...
CYCLONIC SURFACE FLOW IS STILL PRESENT ACROSS THE WEST ATLC
AROUND THE LOW PRESSURE SYSTEM TO THE NORTH. SEVERAL SURGES OF
ENERGY ARE MOVING AROUND THE SYSTEM. FARTHEST WEST...A SURFACE
TROUGH EXTENDS FROM NEAR 31N79W TO THE BIG BEND OF FLORIDA NEAR
30N84W. A COLD FRONT ENTERS THE DISCUSSION AREA NEAR 32N68W AND
CONTINUES TO JUST NORTH OF THE BAHAMAS AT 28N79W. FINALLY...A
SURFACE TROUGH IS TO THE EAST ALONG 30N58W 24N64W 20N72W.
ISOLATED SHOWERS ARE WITHIN 120 NM OF THIS EASTERNMOST TROUGH
IN THE AREA WHERE TROPICAL MOISTURE IS BEING DRAWN TO THE NE
FROM THE CARIBBEAN. ALOFT...AN UPPER LEVEL TROUGH COVERS THE
EASTERN CONUS AND FAR WESTERN ATLC SUPPORTING THE LOW PRESSURE
SYSTEM IN THE NE UNITED STATES. AN UPPER LEVEL RIDGE COVERS THE
CENTRAL ATLC WITH AXIS ALONG 60W. MOSTLY FAIR WEATHER IS NOTED
IN THIS AREA. ACROSS THE EASTERN ATLC...AN UPPER LEVEL LOW NEAR
31N34W CONTINUES TO SUPPORT A 995 MB SURFACE LOW NEAR 30N36W. A
SURFACE TROUGH EXTENDS FROM THE LOW CENTER TOWARDS THE SW ALONG
24N40W 23N48W DEPICTED A WIND SHIFT AROUND THE LOW. A SECOND
SURFACE TROUGH IS FARTHER EAST...REMNANTS OF A FRONTAL
BOUNDARY...ALONG 23N28W TO 13N37W. SCATTERED SHOWERS ARE WITHIN
100 NM EITHER SIDE OF THE AXIS. SCATTERED SHOWERS/POSSIBLE
THUNDERSTORMS CONTINUE TO THE NORTH FROM 24N-32N BETWEEN
19W-28W...AND TO THE EAST FROM 12N-23N BETWEEN 22W-27W. AN UPPER
LEVEL RIDGE COVERS THE FAR EASTERN ATLC SUPPORTING A WEAK
SURFACE RIDGE ACROSS THE WEST ATLC...WHICH HAS AN AXIS THAT
EXTENDS INTO THE DEEP TROPICS PREVENTING THE MONSOON TROUGH/ITCZ
FROM FORMING WEST OF AFRICA.

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

$$
WALTON





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