TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
205 AM EDT MON OCT 22 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
0515 UTC.

…SPECIAL FEATURES…

THE TROPICAL WAVE IN THE W CARIBBEAN HAS BEEN DROPPED FROM THE
22/0000 UTC ANALYSIS. HOWEVER THE 1005 MB LOW REMAINS CENTERED
NEAR 15N78W AS IT CONTINUES TO MOVE THROUGH THE W CARIBBEAN. THE
TOTAL PRECIPITABLE WATER IMAGERY INDICATES A LARGE AREA OF DEEP
MOISTURE COVERING THE CENTRAL CARIBBEAN. CLUSTERS OF SCATTERED
MODERATE/ISOLATED STRONG CONVECTION ARE FROM 12N-18N BETWEEN
74W-79W. SCATTERED SHOWERS AND POSSIBLE ISOLATED THUNDERSTORMS
DOT THE REMAINDER OF THE AREA FROM 11N-18N BETWEEN 77W-84W.
ENVIRONMENTAL CONDITIONS ARE GRADUALLY BECOMING MORE CONDUCIVE
FOR A TROPICAL DEPRESSION TO FORM DURING THE NEXT DAY OR SO. THIS
SYSTEM HAS A HIGH CHANCE OF BECOMING A TROPICAL CYCLONE DURING
THE NEXT 48 HOURS AS IT MOVES SLOWLY TO THE W-SW AND BECOMES
NEARLY STATIONARY WELL TO THE SOUTH OF JAMAICA. HEAVY RAINS FROM
THIS DISTURBANCE ARE LIKELY TO SPREAD OVER JAMAICA…
HISPANIOLA…AND E CUBA DURING THE NEXT SEVERAL DAYS. THESE
RAINS COULD PRODUCE LIFE-THREATENING FLASH FLOODS AND MUD
SLIDES…ESPECIALLY IN AREAS OF HIGH TERRAIN.  

THE TROPICAL WAVE PREVIOUSLY FROM 24N52W TO 15N47W HAS BEEN
DROPPED FROM THE 22/0000 UTC ANALYSIS. HOWEVER THE 1011 MB LOW
REMAINS NEAR 21N51W. THE TOTAL PRECIPITABLE WATER IMAGERY
INDICATES A SMALL AREA OF MODERATE MOISTURE SURROUNDING THE LOW
CENTER. AN UPPER LOW IS SUPPORTING THE SURFACE LOW CENTERED NEAR
21N50W. CLUSTERS OF SCATTERED MODERATE/ISOLATED STRONG
CONVECTION ARE 18N-24N BETWEEN 43W-49W AND FROM 20N-24N BETWEEN
49W-53W.

…TROPICAL WAVES…

TROPICAL WAVE IN THE CENTRAL TROPICAL ATLC IS ANALYZED FROM
14N36W TO 9N39W MOVING SW 5-10 KT. SMALL LOW LEVEL CYCLONIC
CIRCULATION CAN BEEN SEEN ON THE LAST VISIBLE SATELLITE IMAGES.
NO ASSOCIATED DEEP CONVECTION.

A TROPICAL WAVE WAS ADDED TO THE 22/0000 UTC ANALYSIS FROM
17N19W TO 11N21W. WAVE IS EMBEDDED WITHIN A WEAK SURGE OF DEEP
MOISTURE AS DEPICTED ON THE TOTAL PRECIPITABLE WATER IMAGERY.
MID LEVEL CYCLONIC CIRCULATION IS OBSERVED ON SATELLITE IMAGERY.
SCATTERED MODERATE CONVECTION IS WITHIN 60/75 NM OF THE WAVE S
OF 13N.

…ITCZ/MONSOON TROUGH…

THE MONSOON TROUGH EXTENDS ACROSS W AFRICA INTO THE E TROPICAL
ATLC NEAR 13N16W S OF THE E TROPICAL WAVE NEAR 10N21W ALONG
11N34W TO 10N37W. THE ITCZ IS NOT EVIDENT IN THE ATLC BASIN.
CLUSTERS OF SCATTERED MODERATE/STRONG CONVECTION ARE WITHIN 150
NM ALONG THE COAST OF W AFRICA S OF 12N W OF 6W. CLUSTERS OF
SCATTERED MODERATE/ISOLATED STRONG CONVECTION DOT THE AREA FROM
2N-7N BETWEEN 15W-20W AND FROM 7N-12N BETWEEN 21W-42W.

…DISCUSSION…

GULF OF MEXICO…
A BROAD UPPER RIDGE EXTENDS FROM SW MEXICO OVER TEXAS GIVING THE
GULF NW FLOW ALOFT DRAWING DRY CONTINENTAL AIR OVER THE GULF. A
BROAD SURFACE RIDGE DOMINATES THE GULF TONIGHT ANCHORED BY A
1021 MB HIGH OVER NORTH CAROLINA AND A 1022 MB HIGH OVER WEST
VIRGINIA. MODERATE RETURN FLOW HAS SET UP OVER THE NW GULF. THE
FRONT IN THE ATLC DISSIPATES OVER W CUBA NEAR 22N84W GENERATING
CLUSTERS OF ISOLATED SHOWERS/THUNDERSTORMS WITHIN 45 NM ALONG
THE N COAST OF CUBA E OF 84W. ISOLATED SHOWERS/THUNDERSTORMS ARE
ALSO MOVING OFF THE YUCATAN PENINSULA INTO THE BAY OF CAMPECHE S
OF 20N E OF 94W LEAVING THE REMAINDER OF THE GULF WITH
REMARKABLY CLEAR SKIES TONIGHT. WINDS WILL INCREASE ACROSS THE
SE GULF BY TUE BETWEEN SURFACE RIDGE ANCHORED OVER NORTH
CAROLINA AND LOW PRESSURE IN THE CARIBBEAN DESCRIBED IN THE
SPECIAL FEATURES.

CARIBBEAN SEA…
SEE SPECIAL FEATURES ABOVE FOR THE 1005 MB LOW IN THE CENTRAL
CARIBBEAN. AN UPPER TROUGH IN THE W ATLC DIPS S OVER THE NW
CARIBBEAN ACROSS CUBA NEAR 23N80W TO 18N85W GENERATING SCATTERED
SHOWERS/ISOLATED THUNDERSTORMS WITHIN 45 NM OF LINE FROM 18N81W
TO 17N87W. AN UPPER RIDGE AXIS EXTENDS ACROSS CENTRAL AMERICA
ALONG 16N TO ACROSS THE CARIBBEAN. ABUNDANT MOISTURE REMAINS
OVER THE AREA ENHANCING THE SCATTERED/NUMEROUS SHOWERS/SCATTERED
THUNDERSTORMS S OF 15N TO INLAND OVER NW VENEZUELA/NE COLOMBIA
BETWEEN 70W-74W AND SCATTERED SHOWERS/ISOLATED THUNDERSTORMS
ACROSS THE CENTRAL CARIBBEAN BETWEEN 66W-80W. THE SPECIAL
FEATURES LOW WILL DRIFT W THROUGH LATE MON THEN DEEPEN…
POSSIBLY INTO A TROPICAL CYCLONE…AS IT SHIFTS N TO NE TO NEAR
JAMAICA BY WED…AND INTO E CUBA THU AND FRI.

ATLANTIC OCEAN…
BROAD UPPER TROUGH COVERS THE W ATLC W OF 65W SUPPORTING A COLD
FRONT THAT ENTERS THE DISCUSSION AREA JUST E OF BERMUDA ALONG
27N68W TO THE CENTRAL BAHAMAS NEAR 25N75W WHERE IT BECOMES A
DISSIPATING STATIONARY FRONT TO OVER W CUBA NEAR 22N84W.
SCATTERED SHOWERS/ISOLATED THUNDERSTORMS ARE S OF THE FRONT TO
OVER CUBA AND HISPANIOLA BETWEEN 70W-80W AND WITHIN 60 NM NW OF
THE FRONT S OF 28N. THE UPPER RIDGE OVER THE CARIBBEAN EXTENDS A
RIDGE AXIS N OF ACROSS HISPANIOLA NEAR 19N69W TO BEYOND 32N59W
ENHANCING THE ABOVE ACTIVITY. THE UPPER LOW ASSOCIATED WITH THE
1011 MB LOW IN THE SPECIAL FEATURES COVERS THE CENTRAL ATLC N OF
10N BETWEEN 42W-60W. AN UPPER TROUGH IN THE NE ATLC DIPS S TO
23N E OF 35W SUPPORTING A COLD FRONT THAT EXTENDS THROUGH 32N23W
ALONG 30N31W TO 30N38W WHERE IT DISSIPATES TO 31N42W. ISOLATED
SHOWERS ARE POSSIBLE WITHIN 30 NM OF THE FRONT. A BROAD UPPER
RIDGE COVERS THE TROPICAL ATLC E OF 43W AND IS ANCHORED NEAR
10N34W. A SURFACE TROUGH IS TO THE N OF THE UPPER RIDGE
EXTENDING FROM 21N33W TO 19N34W. W ATLC COLD FRONT WILL SHIFT E
TO ALONG 32N55W TO 27N61W ON MON NIGHT THEN NE OUT OF THE AREA
BY TUE NIGHT. SURFACE RIDGE WILL BUILD OFF NORTH CAROLINA COAST
BEHIND THE FRONT THROUGH WED. THE PRESSURE GRADIENT WILL
INCREASE BETWEEN THIS SURFACE RIDGE AND THE DEVELOPING LOW
PRESSURE IN THE CARIBBEAN TUE INTO WED. THE LOW WILL EMERGE N OF
CUBA FRI.