000 AXNT20 KNHC 231037 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 805 AM EDT SUN JUN 23 2013 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 1015 UTC. ...TROPICAL WAVES... TROPICAL WAVE EXTENDS FROM 04N44W TO 11N41W MOVING W AT 20 KT. THE WAVE COINCIDES WITH A 700 MB TROUGH ALONG 44W AND A RELATIVE MAXIMUM IN DEEP LAYER MOISTURE NOTED ON TOTAL PRECIPITABLE WATER IMAGERY FROM 05N-12N BETWEEN 36W-44W. ALSO OF NOTE...THE WAVE IS LOCATED WITHIN AN AREA OF CLEARING EMBEDDED IN THE SAHARAN AIR LAYER SURROUNDING THE WAVE AXIS. WIDELY SCATTERED MODERATE CONVECTION IS FROM 06N-10N BETWEEN 41W-46W. TROPICAL WAVE EXTENDS FROM 04N54W TO 11N53W MOVING W AT 15 KT. THE WAVE LIES WITHIN A RELATIVE MAXIMUM ON TOTAL PRECIPITABLE WATER IMAGERY FROM 06N-11N BETWEEN 52W-58W. SCATTERED MODERATE CONVECTION IS FROM 07N-11N BETWEEN 53W-58W. TROPICAL WAVE EXTENDS FROM 10N85W TO 16N85W MOVING W AT 15 KT. THE WAVE LIES WITHIN ZONAL EASTERLY FLOW AT 700 MB AND IS BECOMING MORE DIFFICULT TO TRACK. WITH SOME OF THE ENERGY FRACTURING SATURDAY...NOW LOCATED OFFSHORE OF THE FLORIDA PENINSULA IN THE SW NORTH ATLC WATERS...THE REMAINING ENERGY IS MOVING BENEATH UNFAVORABLE UPPER LEVEL WINDS AS NORTH- NORTHWESTERLY FLOW ALOFT EXTENDS FROM THE NW GULF OF MEXICO THROUGH TO THE EQUATOR OVER THE EASTERN PACIFIC WATERS. AS A RESULT...CONVECTION REMAINS LIMITED OVERALL WITH ONLY WIDELY SCATTERED MODERATE PRIMPARILY S OF 10N ACROSS COSTA RICA AND THE ADJACENT COASTAL EASTERN PACIFIC WATERS. ...ITCZ/MONSOON TROUGH... THE MONSOON TROUGH EXTENDS FROM THE AFRICAN COAST NEAR 13N17W TO 09N20W. THE INTERTROPICAL CONVERGENCE ZONE AXIS EXTENDS FROM 09N20W TO 07N29W TO 08N41W THEN FROM 05N46W TO 06N52W. SCATTERED MODERATE CONVECTION IS WITHIN 150 NM EITHER SIDE OF THE AXIS BETWEEN 30W-41W. ...DISCUSSION... GULF OF MEXICO... WATER VAPOR IMAGERY INDICATES A MIDDLE TO UPPER LEVEL LOW IS CENTERED OVER THE SE CONUS NEAR 36N85W THAT SUPPORTS SCATTERED SHOWERS AND TSTMS OCCURRING OVER THE NORTH-CENTRAL GULF N OF 27N BETWEEN 86W-92W THIS MORNING. THIS CONVECTION IS LARGELY SUSTAINING ITSELF DUE TO LOW-LEVEL MOISTURE CONVERGENCE AND MID- LEVEL DIFFLUENCE. OTHERWISE...THE REMAINDER OF THE BASIN IS UNDER THE INFLUENCE OF WEAK SURFACE RIDGING EXTENDING FROM THE SW NORTH ATLC REGION WEST-SOUTHWESTWARD TO THE COAST OF MEXICO. ASIDE FROM ANY SMALL VARIATION IN WIND DIRECTION ASSOCIATED WITH SURFACE TROUGHING OVER THE FLORIDA PENINSULA AND THE NE GULF... SYNOPTICALLY EAST-SOUTHEAST WINDS IN THE RANGE OF 10 TO 15 KT ARE EXPECTED THROUGH EARLY MONDAY. THE RIDGE IS EXPECTED TO MAINTAIN ITSELF THROUGHOUT MUCH OF THE WEEK AHEAD. CARIBBEAN SEA... THE CARIBBEAN IS LARGELY INFLUENCED BY A MIDDLE TO UPPER LEVEL LOW CENTERED NORTH OF EASTERN CUBA NEAR 21N75W. THE ASSOCIATED TROUGH AXIS DIPS WEST-SOUTHWEST TO 18N83W. WATER VAPOR IMAGERY INDICATES THE AREA WITHIN THE TROUGH IS RELATIVELY DRY AND STABLE ALOFT WHICH IS PROVIDING FOR OVERALL TRANQUIL CONDITIONS N OF 15N BETWEEN 74W-88W. OTHERWISE...ON THE SOUTHWEST PERIPHERY OF THE TROUGHING...NORTH-NORTHWESTERLY FLOW ALOFT DOMINATES AND IS PROVIDING FOR SUFFICIENT UPPER LEVEL DIFFLUENCE TO SUPPORT WIDELY SCATTERED SHOWERS AND TSTMS S OF 15N W OF 76W...INCLUDING INLAND PORTIONS OF CENTRAL AMERICA. MOST ACTIVE CONVECTION THIS MORNING IS SOUTH OF THE MONSOON TROUGH AXIS ALONG 10N... INCLUDING COSTA RICA...PANAMA...AND THE ADJACENT COASTAL WATERS. EAST OF THE UPPER LEVEL TROUGH AXIS...SOUTHWESTERLY FLOW ALOFT CONTINUES TO ADVECT MOISTURE FROM OVER NORTHERN SOUTH AMERICA TOWARDS THE MONA PASSAGE AND PUERTO RICO. MOST OF THIS MOISTURE REMAINS AS INCREASED CLOUD COVER ACROSS THE EASTERN CARIBBEAN... HOWEVER A FEW ISOLATED LOW-TOPPED SHOWERS ARE NOTED ON SATELLITE IMAGERY N OF 14N BETWEEN 63W-74W...THAT STRETCH NORTHEASTWARD INTO THE ADJACENT WATERS OF THE SW NORTH ATLC. HISPANIOLA... CURRENTLY CONDITIONS REMAIN RELATIVELY TRANQUIL THIS MORNING ACROSS THE ISLAND...HOWEVER A FEW ISOLATED LIGHT SHOWERS ARE NOTED ON SATELLITE IMAGERY. WATER VAPOR IMAGERY INDICATES AN UPPER LEVEL LOW IS CENTERED NORTHWEST OF THE ISLAND NEAR 21N75W WITH PRIMARILY MOIST SOUTHWESTERLY FLOW ALOFT LOCATED EAST OF THE ISLAND OVER PUERTO RICO...THE MONA PASSAGE...AND FAR EASTERN DOMINICAN REPUBLIC. GLOBAL MODEL DATA INDICATES THE LOW WILL WEAKEN OVER THE NEXT FEW DAYS AND LIFT GRADUALLY NORTHWARD WITH SOUTHWESTERLY FLOW ALOFT BECOMING DOMINANT THROUGH EARLY NEXT WEEK. THIS...ALONG WITH LOW-LEVEL MOISTURE IN PLACE ACROSS THE EASTERN GREATER ANTILLES WILL RESULT IN AN ATMOSPHERE THAT WILL FAVOR BEING UNSTABLE DURING THE AFTERNOON AND EVENING HOURS WITH SCATTERED SHOWERS AND TSTMS EXPECTED DUE TO PEAK DAYTIME HEATING AND INSTABILITY. ATLANTIC OCEAN... A MIDDLE TO UPPER LEVEL LOW CENTERED OVER THE SE CONUS NEAR 36N85W SUPPORTS WEAK SURFACE TROUGHING INLAND ACROSS PORTIONS OF THE SE CONUS THIS MORNING. A SURFACE TROUGH...ANALYZED FROM 27N81W TO 31N78W CONTINUES TO MOVE NW TOWARDS THE FLORIDA PENINSULA AND SE CONUS COAST. ISOLATED SHOWERS AND TSTMS ARE OCCURRING WITHIN 90 NM EITHER SIDE OF THE SURFACE TROUGH. OTHERWISE...THE REMAINDER OF THE CENTRAL AND EASTERN ATLC IS UNDER THE INFLUENCE OF A SURFACE RIDGE ANCHORED BY A 1033 MB HIGH CENTERED NORTH OF THE AZORES NEAR 40N29W AND A 1026 MB HIGH CENTERED IN THE VICINITY OF BERMUDA NEAR 33N66W. A STABLE DRY AIRMASS COVERS MUCH OF THE EASTERN ATLC INDICATED BY A LARGE AREA OF SUSPENSED SAHARAN DUST THAT EXTENDS FROM THE COAST OF AFRICA TO 55W. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ HUFFMAN