000WTNT32 KNHC 121453TCPAT2BULLETINTROPICAL DEPRESSION TWELVE ADVISORY NUMBER 1NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL1220101100 AM AST SUN SEP 12 2010...TROPICAL DEPRESSION FORMS IN THE FAR EASTERN ATLANTIC...TROPICALSTORM WARNING ISSUED FOR THE SOUTHERN CAPE VERDE ISLANDS...SUMMARY OF 1100 AM AST...1500 UTC...INFORMATION-----------------------------------------------LOCATION...12.7N 21.4WABOUT 250 MI...400 KM SE OF THE SOUTHERNMOST CAPE VERDE ISLANDSMAXIMUM SUSTAINED WINDS...35 MPH...55 KM/HRPRESENT MOVEMENT...W OR 275 DEGREES AT 14 MPH...22 KM/HRMINIMUM CENTRAL PRESSURE...1006 MB...29.71 INCHESWATCHES AND WARNINGS--------------------CHANGES WITH THIS ADVISORY...THE GOVERNMENT OF THE CAPE VERDE ISLANDS HAS ISSUED A TROPICAL STORMWARNING FOR THE SOUTHERN CAPE VERDE ISLANDS...INCLUDING MAIO..SAOTIAGO...FOGO...AND BRAVA.SUMMARY OF WATCHES AND WARNINGS IN EFFECT...A TROPICAL STORM WARNING IS IN EFFECT FOR...* THE SOUTHERN CAPE VERDE ISLANDS...INCLUDING MAIO..SAO TIAGO...FOGO...AND BRAVAA TROPICAL STORM WARNING MEANS THAT TROPICAL STORM CONDITIONS AREEXPECTED IN THE WARNING AREA...IN THIS CASE IN THE NEXT 12 TO 24HOURS.FOR STORM INFORMATION SPECIFIC TO YOUR AREA...PLEASE MONITORPRODUCTS ISSUED BY YOUR NATIONAL METEOROLOGICAL SERVICE.DISCUSSION AND 48-HOUR OUTLOOK------------------------------AT 1100 AM AST...1500 UTC...THE CENTER OF TROPICAL DEPRESSION TWELVEWAS LOCATED NEAR LATITUDE 12.7 NORTH...LONGITUDE 21.4 WEST. THEDEPRESSION IS MOVING TOWARD THE WEST NEAR 14 MPH...22 KM/HR. THISGENERAL MOTION IS EXPECTED TO CONTINUE FOR THE NEXT COUPLE OF DAYS.ON THE FORECAST TRACK...THE CENTER OF THE DEPRESSION IS EXPECTED TOPASS NEAR THE SOUTHERNMOST CAPE VERDE ISLANDS TONIGHT AND MONDAY.MAXIMUM SUSTAINED WINDS ARE NEAR 35 MPH...55 KM/HR...WITH HIGHERGUSTS. SOME STRENGTHENING IS FORECAST DURING THE NEXT COUPLE OFDAYS...AND THE DEPRESSION IS EXPECTED TO BECOME A TROPICAL STORMTONIGHT OR MONDAY.ESTIMATED MINIMUM CENTRAL PRESSURE IS 1006 MB...29.71 INCHES.HAZARDS AFFECTING LAND----------------------WIND...TROPICAL STORM CONDITIONS ARE EXPECTED TO REACH THE WARNINGAREA TONIGHT.RAINFALL...THE DEPRESSION IS EXPECTED TO PRODUCE TOTAL RAINACCUMULATIONS OF 3 TO 5 INCHES OVER MUCH OF THE CAPE VERDE ISLANDS...WITH POSSIBLE ISOLATED MAXIMUM AMOUNTS OF 8 INCHES. THESE RAINSCOULD CAUSE LIFE-THREATENING FLASH FLOODS AND MUDSLIDES.NEXT ADVISORY-------------NEXT INTERMEDIATE ADVISORY...200 PM AST.NEXT COMPLETE ADVISORY...500 PM AST.$$FORECASTER BRENNAN
Intensity forecast for 92LNHC is putting the odds of 92L developing into a tropical depression by Tuesday at 50%; I'd put them higher, at 70%. However, time is running out for 92L to become a hurricane before hitting the Yucatan Peninsula on Wednesday. Given the current disorganized state of 92L, it would be difficult for it to intensify quickly enough to become a hurricane by then. The storm may also suffer another of its mysterious evening collapses, where it loses most of its heavy thunderstorm activity. However, the SHIPS model predicts wind shear will remain low, 5 - 10 knots, through the period, and water temperatures are certainly warm enough to support development. The main detriment to intensification is likely to be dry air, and 92L could wrap in some of the dry air to its northwest at times, slowing down development. There are a number of research flights being made into 92L this afternoon that should help long-term efforts to make better predictions in the future on whether or not disturbances like this will develop or not.
000WTNT42 KNHC 130248TCDAT2TROPICAL STORM JULIA DISCUSSION NUMBER 3NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL1220101100 PM AST SUN SEP 12 2010INFRARED AND MICROWAVE SATELLITE IMAGERY SHOW THAT THE CENTER OFTHE CYCLONE IS LOCATED NEAR THE EASTERN EDGE OF A CURVED BAND OFCONVECTION THAT WRAPS AROUND THE WESTERN SEMICIRCLE OF THE SYSTEM.SUBJECTIVE DVORAK INTENSITY ESTIMATES ARE 35 KT FROM TAFB AND 30 KTFROM SAB. OBJECTIVE DVORAK ESTIMATES FROM UW/CIMMS ARE SLIGHTLYHIGHER. A BLEND OF THESE ESTIMATES SUPPORT AN UPGRADE OF THEDEPRESSION TO A 35-KT TROPICAL STORM...THE TENTH OF THE 2010 ATLANTIC HURRICANE SEASON.THE EASTERLY SHEAR IS EXPECTED TO WEAKEN DURING THE NEXT 12 HOURSAND IS FORECAST TO REMAIN LIGHT OVER THE NEXT COUPLE OF DAYS.DURING THAT TIME JULIA WILL BE TRAVERSING WARM WATER AND AS ARESULT...STEADY STRENGTHENING IS ANTICIPATED. THE SHIPS...LGEM...AND GFDL MODELS ALL BRING JULIA TO HURRICANE STATUS WITHIN TWO DAYSAND THE NHC FORECAST IS IN GOOD AGREEMENT. THEREAFTER...JULIA WILLBE MOVING OVER SLIGHTLY COOLER SEA SURFACE TEMPERATURES AND INTO ANAREA OF INCREASING SOUTHWESTERLY SHEAR TO THE EAST OF ANUPPER-LEVEL LOW/TROUGH BETWEEN 30W AND 40W. IT IS A BIT SURPRISINGGIVEN THESE NEGATIVE FACTORS THAT THE INTENSITY GUIDANCE SHOWSLITTLE...IF ANY...WEAKENING. BECAUSE OF THAT...THE OFFICIALFORECAST WILL KEEP JULIA AT 65 KT AT DAYS 3-5 FOR NOW.THE CENTER OF JULIA WAS RELOCATED A LITTLE EAST OF THE PREVIOUSADVISORY POSITION BASED ON THE EARLIER MICROWAVE DATA. THE INITIALMOTION ESTIMATE IS 285/10. THE TRACK FORECAST REASONING REMAINSTHE SAME AS THE PREVIOUS ADVISORY. JULIA IS FORECAST TO MOVEWEST-NORTHWESTWARD AROUND THE SOUTHWESTERN SIDE OF A MID-LEVELRIDGE THAT EXTENDS FROM AFRICA WESTWARD INTO THE EASTERN ATLANTIC. IN A COUPLE OF DAYS...THE CYCLONE IS FORECAST TO TURN NORTHWESTWARDTOWARD A WEAKNESS IN THE RIDGE. MOST OF THE GUIDANCE INDICATES ATURN BACK TOWARD THE WEST-NORTHWEST LATE IN THE PERIOD AS JULIAMOVES AROUND THE NORTH SIDE OF AN UPPER-LEVEL LOW THAT CUTS OFFNEAR 40W. THE OFFICIAL FORECAST TRACK IS GOOD AGREEMENT WITH THEPREVIOUS ADVISORY AND A BLEND OF THE LATEST RUNS OF THE GFS...UKMET...GFDL...HWRF...AND ECMWF MODELS.FORECAST POSITIONS AND MAX WINDSINITIAL 13/0300Z 13.5N 23.5W 35 KT 12HR VT 13/1200Z 14.0N 25.3W 45 KT 24HR VT 14/0000Z 14.9N 27.6W 50 KT 36HR VT 14/1200Z 15.9N 29.5W 55 KT 48HR VT 15/0000Z 17.1N 31.1W 65 KT 72HR VT 16/0000Z 20.9N 35.1W 65 KT 96HR VT 17/0000Z 24.5N 41.0W 65 KT120HR VT 18/0000Z 27.5N 46.5W 65 KT$$FORECASTER BROWN
000WTNT42 KNHC 132039TCDAT2TROPICAL STORM JULIA DISCUSSION NUMBER 6NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL122010500 PM AST MON SEP 13 2010SATELLITE IMAGERY SHOWS THAT JULIA HAS BECOME BETTER ORGANIZED THISAFTERNOON...AS THE EASTERLY SHEAR APPEARS TO HAVE DIMINISHED A BIT. BANDING CONTINUES TO IMPROVE OVER THE WESTERN SEMICIRCLE AND ASMALL IRREGULAR CENTRAL DENSE OVERCAST FEATURE IS DEVELOPING OVERTHE CENTER. THE INITIAL INTENSITY OF 45 KT IS BASED ON A BLEND OFDVORAK ESTIMATES OF 35 AND 45 KT FROM TAFB AND SAB...RESPECTIVELY...AND A UW-CIMSS ADT ESTIMATE OF 53 KT USING THE SHEAR PATTERN.THE LARGE-SCALE MODELS...THE LGEM...AND THE SHIPS MODEL CONTINUE TOSHOW AN UPPER-LEVEL WIND ENVIRONMENT CONDUCIVE FOR STRENGTHENINGDURING THE NEXT 36 TO 48 HOURS. AFTER THAT TIME...THE CYCLONESHOULD FEEL THE AFFECTS OF INCREASING WESTERLY SHEAR DUE TO ANAMPLIFYING MID- TO UPPER-LEVEL TROUGH OVER THE EASTERN SUBTROPICALATLANTIC...WHICH SHOULD CURTAIL FURTHER INTENSIFICATION. THE NHCINTENSITY FORECAST CALLS FOR JULIA TO BECOME A HURRICANE IN 24HOURS AND THEN BASICALLY MAINTAIN THIS INTENSITY THROUGH DAY 4. AFTERWARD...THE DYNAMICAL MODELS ALL SUGGEST THAT THE UPPER-LEVELOUTFLOW ASSOCIATED WITH LARGER HURRICANE IGOR WILL PRODUCE MODERATETO STRONG NORTHEASTERLY SHEAR OVER JULIA. THIS INCREASE IN SHEARIS REFLECTED IN THE NHC FORECAST...WHICH SHOWS JULIA WEAKENINGTO A TROPICAL STORM AT DAY 5.THE INITIAL MOTION IS BASICALLY THE SAME AS THE PREVIOUS ADVISORYAND IS ESTIMATED TO BE WEST-NORTHWESTWARD...OR 295/12. THE GFS...GFS ENSEMBLE MEAN...HWRF...AND THE GFDL ARE NOW INDICATING MOREOF A NORTHWESTWARD MOTION DURING THE 24 TO 36 HOUR PERIOD DUE TO ADEVELOPING MID- TO UPPER-LEVEL CUT-OFF LOW LOCATED NORTH-NORTHWESTOF JULIA. HOWEVER...THE NOGAPS...ECMWF...AND UKMET SHOW ACONTINUED WEST-NORTHWESTWARD TRACK...WHICH APPEARS TO BE DUE TO ASHALLOWER VERTICAL STRUCTURE OF THE CYCLONE. THROUGH THE REMAINDEROF THE FORECAST PERIOD...THE EASTERN EXTENT OF THE SUBTROPICALRIDGE GRADUALLY BUILDS NORTHEAST OF THE JULIA AS THE AFOREMENTIONEDCUT-OFF LOW WEAKENS AND DISSIPATES. THIS SHOULD ALLOW JULIA TOMAINTAIN A GENERAL NORTHWESTWARD MOTION. THE OFFICIAL FORECAST ISBASED ON THE TVCN CONSENSUS MODEL AND IS WEIGHTED MORE TOWARD THEMODELS THAT INDICATE A TURN TOWARD THE NORTHWEST AROUND 36 HOURS.FORECAST POSITIONS AND MAX WINDSINITIAL 13/2100Z 15.3N 27.5W 45 KT 12HR VT 14/0600Z 16.0N 29.0W 50 KT 24HR VT 14/1800Z 17.3N 30.8W 65 KT 36HR VT 15/0600Z 18.8N 32.4W 65 KT 48HR VT 15/1800Z 20.5N 34.4W 70 KT 72HR VT 16/1800Z 23.8N 39.7W 70 KT 96HR VT 17/1800Z 27.0N 46.0W 65 KT120HR VT 18/1800Z 30.0N 49.5W 55 KT$$FORECASTER ROBERTS/BRENNAN