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000
AXNT20 KNHC 220000
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT TUE OCT 21 2014

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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 2345 UTC.


...SPECIAL FEATURES...

AS OF 2100 UTC...A 1001 MB LOW PRESSURE CENTER IS CENTERED OVER THE BAY OF CAMPECHE NEAR 19N93W DRIFTING E. SHOWER AND THUNDERSTORM ACTIVITY WITH THIS LOW REMAINS DISORGANIZED AND IS CONFINED TO THE E SEMICIRCLE OF THE SYSTEM AND EXTENDS EASTWARD ACROSS THE YUCATAN PENINSULA AND THE YUCATAN CHANNEL. THE SYSTEM IS SITUATED BETWEEN AN UPPER LEVEL TROUGH OVER MEXICO AND A RIDGE OVER THE GULF E OF 90W. THE UPPER CONDITIONS COULD BECOME MORE CONDUCIVE FOR ADDITIONAL DEVELOPMENT ON WED AND THERE IS A MEDIUM CHANCE OF TROPICAL CYCLONE FORMATION OVER THE NEXT 48 HOURS.

A 1001 MB GALE CENTER WAS OVER THE EASTERN ATLANTIC NEAR 33N28W DRIFTING W. SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS WERE NOTED WITHIN 300 NM IN THE EASTERN SEMICIRCLE OF THE GALE CENTER. THE HIGH SEAS FORECASTS ISSUED BY METEO-FRANCE INDICATED WINDS FOR THE IRVING AND ACORES ZONES HAVE DROPPED BELOW GALE FORCE. SEE TEXT FORECASTS UNDER WMO HEADER FQNT52 LFPW FOR ADDITIONAL INFORMATION.


...TROPICAL WAVES...

TROPICAL WAVE OVER THE EASTERN ATLANTIC EXTENDS FROM 12N32W TO 5N35W WAS INTRODUCED INTO THE SURFACE ANALYSIS BASED ON SATELLITE HOVMOLLER ANALYSIS AND UNIVERSITY OF ALBANY EASTERLY WAVE DIAGNOSTICS. SCATTERED MODERATE ISOLATED STRONG CONVECTION WAS NOTED WITHIN 240 NM E OF THE WAVE AXIS FROM 8N-10N.

TROPICAL WAVE OVER THE CENTRAL TROPICAL ATLC EXTENDS FROM 18N52W TO 6N54W MOVING W AT 15 KT. THE WAVE IS EMBEDDED WITHIN A BROAD AREA OF DEEP MOISTURE AS DEPICTED ON THE TOTAL PRECIPITABLE WATER IMAGERY. SCATTERED MODERATE TO STRONG CONVECTION WAS NOTED WITHIN 240 NM EITHER SIDE OF THE WAVE AXIS AND ELSEWHERE WITHIN AN AREA FROM 7N-16N BETWEEN 49W-58W.


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

THE MONSOON TROUGH EXTENDS ACROSS AFRICA TO THE COAST OF SIERRA LEONE NEAR 8N13W AND CONTINUES TO 7N16W. THE ITCZ EXTENDS FROM 7 7N16W TO 8N33W TO 7N42W TO 10N51W TO 8N58W. BESIDES THE CONVECTION MENTIONED IN THE TROPICAL WAVES SECTION...SCATTERED MODERATE CONVECTION IS FROM 3N-10N BETWEEN 12W-18W...AND FROM 4N- 9N BETWEEN 22W-30W.


...DISCUSSION...

GULF OF MEXICO...

AS OF 2100 UTC...A 1001 MB LOW PRESSURE CENTER IS CENTERED OVER THE BAY OF CAMPECHE NEAR 19N93W DRIFTING E...REFER TO SPECIAL FEATURES SECTION ABOVE FOR ADDITIONAL DETAILS. A SURFACE TROUGH EXTENDS FROM 24N85W TO NEAR THE LOW CENTER AT 21N93W. ANOTHER SURFACE TROUGH EXTENDS FROM THE LOW CENTER NNW TO NEAR 24N96W. A STATIONARY FRONT WAS DRAPED ACROSS THE NORTHERN GULF OF MEXICO FROM THE TAMPA BAY AREA THROUGH 26N90W TO 25N97W. FRESH NE WINDS WERE NOTED N OF THE FRONT WITH SOME DRIER AIR FILTERING SOUTHWARD OVER THE GULF COAST AND NORTHERN GULF. SCATTERED MODERATE TO STRONG CONVECTION WAS NOTED WITHIN 240 NM IN THE E SEMICIRCLE OF THE LOW AND SURFACE TROUGH AND EXTENDED OVER THE YUCATAN PENINSULA AND YUCATAN CHANNEL. ADDITIONAL ACTIVITY WAS OVER CUBA AND THE STRAITS OF FLORIDA AND S-CENTRAL FLORIDA. IN THE UPPER LEVELS...AN UPPER LEVEL RIDGE IS OVER THE GULF E OF 90W WITH AXIS ALONG 82W. AN UPPER TROUGH WAS LOCATED OVER MEXICO ALONG 97W. THE BASE OF A SHARP MID-TO UPPER LEVEL TROUGH WAS GRAZING THE NE GULF WITH STRONG DEEP LAYERED SUBSIDENCE. SHOWERS AND THUNDERSTORMS ARE EXPECTED TO MOVE EASTWARD OVER THE E GULF THE FLORIDA KEYS AND SOUTH FLORIDA WITH THE POTENTIAL FOR LOCALLY HEAVY RAINFALL IN AREAS OF TRAINING CONVECTION.

CARIBBEAN SEA...

SURFACE AND SCATTEROMETER DATA INDICATED LIGHTER THAN NORMAL TRADES ACROSS THE CARIBBEAN WITH WINDS GENERALLY 10-15 KT...EXCEPT FOR ISOLATED AREAS OF 20 KT WINDS OVER THE NE GULF AND THE GULF OF HONDURAS. SCATTERED SHOWERS AND ISOLATED THUNDERSTORM COVERED THE NW THIRD OF THE CARIBBEAN EXTENDING OVER PORTIONS OF CUBA...JAMAICA...THE YUCATAN PENINSULA AND CHANNEL. FAIR CONDITIONS PREVAILED OVER THE CARIBBEAN E OF 75W INCLUDING HISPANIOLA. IN THE UPPER LEVELS...A RIDGE IS OVER THE W CARIBBEAN AND CENTRAL AMERICA W OF 75W WITH MAJOR AXIS EXTENDING NE ACROSS CUBA...THE BAHAMAS INTO THE SW N ATLANTIC NEAR 25N68W. DOWNSTREAM TROUGH AXIS EXTENDED FROM A CYCLONIC CIRCULATION NEAR 22N58W SW ACROSS PUERTO RICO INTO THE CENTRAL CARIBBEAN TO A BASE NEAR 12N74W. SCATTERED MODERATE TO STRONG CONVECTION IS EXPECTED TO INCREASE OVER THE NW CARIBBEAN OVER THE NEXT FEW DAYS AS THE SURFACE LOW IN THE BAY OF CAMPECHE MOVES EASTWARD. LOCALLY HEAVY RAINFALL IS POSSIBLE OVER YUCATAN AND CUBA.

HISPANIOLA...

FAIRLY DEEP LAYERED SUBSIDENCE WAS NOTED OVER HISPANIOLA PER WATER VAPOR IMAGERY. AS A RESULT DIURNAL CONVECTIVE ACTIVITY TODAY WAS VERY ISOLATED AND SHORT LIVED. THIS SAME GENERAL SCENARIO SHOULD PREVAIL OVER THE ISLANDS THE NEXT FEW DAYS AS THE AREA REMAINS SITUATED IN THE SUBSIDENT REGION OF THE MID TO UPPER LEVEL RIDGE.

ATLANTIC OCEAN...

THE COLD FRONT OVER THE NW ATLANTIC FROM 31N77W TO NEAR DAYTONA BEACH FLORIDA HAS BECOME STATIONARY. A PRE-FRONTAL TROUGH EXTENDED FROM 31N76W TO NEAR FREEPORT BAHAMAS. SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS WERE NOTED BETWEEN THE PRE-FRONTAL TROUGH AND THE FRONTAL SYSTEM. FURTHER EAST...A 1012 MB LOW IS OVER THE CENTRAL ATLANTIC NEAR 27N54W DRIFTING TO THE N. A SURFACE TROUGH EXTENDS FROM 31N53W TO THE LOW CENTER TO 23N57W. ANOTHER SURFACE TROUGH...POSSIBLY REMNANTS OF AN OLD FRONT EXTENDS FROM 29N51W SE THROUGH 23N47W TO 19N40W. SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS WERE NOTED WITHIN 90-=120 NM EITHER SIDE OF THE TROUGH FROM 24N-30N. A 1001 MB GALE LOW IS CENTERED OVER THE EASTERN ATLANTIC NEAR 33N26W DRIFTING W. THIS GALE LOW WAS NEARLY STACKED WITH A VERY LARGE UPPER LEVEL LOW IS CENTERED NEAR 34N28W. A SURFACE TROUGH EXTENDS S FROM THE LOW CENTER THROUGH 30N27W TO 24N31W. ELSEWHERE IN THE UPPER LEVELS...THE OVERALL FLOW WAS AMPLIFIED WITH A BROAD UPPER TROUGH DOMINATING THE ATLANTIC N OF 20N AND E OF 40W...ASSOCIATED WITH THE LARGE CYCLONE NEAR THE AZORES.

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

$$ COBB

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