Tropical Weather Discussion
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000 AXNT20 KNHC 291026 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 805 AM EDT TUE JUL 29 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1030 UTC. ...SPECIAL FEATURE... A DISTURBANCE OVER THE CENTRAL TROPICAL ATLANTIC HAS BECOME BETTER ORGANIZED DURING THE PAST SEVERAL HOURS. THE SYSTEM IS ASSOCIATED WITH A 1010 MB LOW EMBEDDED IN THE MONSOON TROUGH NEAR 9N37W. A CLUSTER OF MODERATE CONVECTION IS FROM 8N-11N BETWEEN 36W-40W. RAINBANDS OF MODERATE CONVECTION ARE ELSEWHERE FROM 4N-14N BETWEEN 33W-42W. THERE IS A HIGH CHANCE OF FURTHER DEVELOPMENT OF THIS DISTURBANCE WITHIN 48 HOURS. SEE THE LATEST NHC TROPICAL WEATHER OUTLOOK UNDER AWIPS/WMO HEADERS MIATWOAT/ABNT20 KNHC FOR MORE DETAILS. ...TROPICAL WAVES... A TROPICAL WAVE IS OVER THE EASTERN ATLC WITH AXIS EXTENDING FROM 15N19W TO 5N20W MOVING W AT 10 KT. THE NORTHERN ENVIRONMENT OF THE WAVE IS EMBEDDED IN THE DRY SAHARAN AIR LAYER WHILE S OF 11N THE WAVE IS ASSOCIATED WITH DEEP LAYER MOISTURE. SCATTERED MODERATE CONVECTION IS IN THE SOUTHERN WAVE ENVIRONMENT FROM 6N- 10N BETWEEN 15W-28W. A TROPICAL WAVE IS W-NW OF AN AREA OF DISTURBED WEATHER OVER THE CENTRAL ATLC. THE AXIS OF THE WAVE EXTENDS FROM 18N42W TO 9N40W MOVING W AT 10 KT DURING THE PAST 24 HOURS. MOST OF THE WAVE ENVIRONMENT IS IN THE DRY SAHARAN AIR LAYER WHICH IS HINDERING THE DEVELOPMENT OF DEEP CONVECTION. ...ITCZ/MONSOON TROUGH... MONSOON TROUGH EXTENDS FROM THE COAST OF WEST AFRICA NEAR 11N16W TO 7N28W TO A 1010 MB LOW NEAR 9N37W TO 7N41W. THE INTERTROPICAL CONVERGENCE ZONE AXIS EXTENDS FROM 7N42W TO 7N54W. AREAS OF CONVECTION ARE ASSOCIATED WITH TROPICAL WAVES. SEE THE SECTIONS ON TROPICAL WAVES AND SPECIAL FEATURES FOR DETAILS. ...DISCUSSION... GULF OF MEXICO... A BROAD MID-UPPER LEVEL TROUGH EXTENDS ACROSS THE EASTERN CONUS SUPPORTING A COLD FRONT ANALYZED FROM 30N84W TO 30N87W THEN ACROSS LOUISIANA TO TEXAS. A PRE-FRONTAL TROUGH IS ALONG THE NORTHERN GULF EXTENDING FROM 30N84W 28N90W TO 28N95W AND SUPPORTING SCATTERED SHOWERS AND TSTMS N OF 27N E OF 94W. OVER THE SW GULF...SCATTERED MODERATE CONVECTION AND TSTMS ARE S OF 20N E OF 96W ASSOCIATED WITH THE NORTHERN PORTION OF A TROPICAL WAVE MOVING INTO E PACIFIC WATERS. THE REST OF THE GULF IS BEING INFLUENCED BY RIDGING ALOFT WHICH IS SUPPORTING A 1017 MB HIGH NEAR 25N89W. DRY AIR SUBSIDENCE FROM ALOFT ALONG WITH SURFACE HIGH PRESSURE PROVIDE A GENERAL STABLE ENVIRONMENT THAT SUPPORT FAIR WEATHER ELSEWHERE IN THE GULF. VARIABLE WINDS OF 5-15 KT PREVAILS ACROSS THE GULF. THE FRONT WILL MOVE INTO THE NE GULF LATER TODAY WHERE IT IS EXPECTED TO TRANSITION BACK INTO A STATIONARY FRONT LATER DURING THE DAY. SURFACE RIDGING WILL PREVAIL ELSEWHERE DURING THIS PERIOD. CARIBBEAN SEA... WITH THE EXCEPTION TO THE FAR WESTERN AND SW CARIBBEAN...LOWER TO MIDDLE LEVEL DRY AIR DOMINATES ACROSS THE REGION ALONG WITH STRONG DEEP LAYER ENVIRONMENTAL WIND SHEAR. THESE TWO FACTORS PROVIDE OVERALL STABILITY...THUS SUPPORTING CLEAR SKIES. AN UPPER-LEVEL TROUGH BETWEEN CUBA AND HISPANIOLA SUPPORTS CLOUDINESS AND POSSIBLE ISOLATED SHOWERS ON THE WINDWARD PASSAGE...HAITI AND WESTERN DOMINICAN REPUBLIC. CLOUDINESS AS WELL AS ISOLATED SHOWERS AND TSTMS ASSOCIATED WITH THE PASSAGE OF A TROPICAL WAVE ARE ALONG CENTRAL AMERICA COASTAL WATERS N OF 14N W OF 81W. OVER THE SW BASIN...THE MONSOON TROUGH ENHANCES SHOWERS AND TSTMS S OF 11N W OF 77W. OTHERWISE...A CONTINUAL TIGHT PRESSURE GRADIENT BETWEEN A LOW OVER NORTHERN COLOMBIA AND HIGH PRESSURE FROM THE ATLC EXTENDING INTO THE CARIBBEAN SUPPORT TRADES OF 20-25 KT S OF 17N BETWEEN 66W-83W WITH NEAR GALE FORCE WINDS ALONG THE COAST OF COLOMBIA. A TROPICAL WAVE IS EXPECTED TO ENTER THE EASTERN CARIBBEAN THU MORNING AHEAD OF A POSSIBLE TROPICAL CYCLONE. SEE THE SPECIAL FEATURES SECTION FOR MORE DETAILS. ...HISPANIOLA... CURRENTLY...A TROUGH ALOFT SUPPORTS CLOUDINESS AND POSSIBLE ISOLATED SHOWERS ACROSS HAITI AND WESTERN DOMINICAN REPUBLIC. MOSTLY FAIR WEATHER IS FORECAST FOR TODAY...HOWEVER MODEL GUIDANCE INDICATES SHOWERS ACROSS PORTIONS OF THE ISLAND MOST OF THE DAY WEDNESDAY. ATLANTIC OCEAN... A MID-UPPER LEVEL TROUGH OVER THE EASTERN CONUS ALONG WITH THE SE PERIPHERY OF A RIDGE GENERATE A DIFFLUENT ENVIRONMENT ALOFT OVER THE SW N ATLC WATERS WHICH ALONG MODERATE DEEP LAYER MOISTURE IN THE REGION SUPPORT HEAVY SHOWERS AND TSTMS FROM 25N- 29N BETWEEN 75W-79W. THE REMAINDER BASIN IS FAIRLY DRY AND UNDER THE INFLUENCE OF SURFACE RIDGING ANCHORED BY A 1026 MB HIGH NEAR 34N52W. THESE TWO FACTORS SUPPORTS FAIR WEATHER ELSEWHERE IN THE BASIN. OTHERWISE...SEE ABOVE THE SPECIAL FEATURES AND TROPICAL WAVES SECTIONS. SURFACE RIDGING WILL DOMINATE ACROSS THE CENTRAL AND EASTERN ATLC THE TUE AND WED. A FRONTAL BOUNDARY IS EXPECTED TO MOVE ACROSS THE SW N ATLC TODAY THROUGH THU MORNING. ANOTHER FRONTAL SYSTEM IS EXPECTED TO SINK INTO THE NORTHERN CENTRAL ATLC BY EARLY THU. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ NR

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