000 WTPZ41 KNHC 270840 TCDEP1 TROPICAL DEPRESSION ONE-E DISCUSSION NUMBER 2 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL EP012007 200 AM PDT SUN MAY 27 2007 THE TROPICAL DEPRESSION IS SENDING MIXED MESSAGES THIS MORNING. AN EARLIER QUIKSCAT PASS AT 0146 UTC SHOWED SEVERAL BELIEVABLE WIND SPEEDS JUST BELOW STORM STRENGTH. A LITTLE LATER...AT 0338 UTC... SSMIS MICROWAVE DATA SHOWED A CURVED BAND STRUCTURE AROUND THE CENTER. HOWEVER...SINCE THESE MICROWAVE DATA...THE CONVECTIVE ORGANIZATION OF THE SYSTEM HAS BEEN DETERIORATING. AN EARLIER IMPRESSIVE BAND TO THE SOUTH OF THE CENTER HAS BEEN DRAMATICALLY WEAKENING. THE CENTER...AS DERIVED FROM EARLIER MICROWAVE PASSES...NOW SEEMS TO BE ON THE NORTHERN SIDE OF THE REMAINING DEEP CONVECTION. IT IS A LITTLE ODD THAT THUNDERSTORMS ARE PREFERENTIALLY FORMING ON THE SOUTHEASTERN PORTION OF THE CIRCULATION WHEN THE SHEAR IS COMING FROM THE SOUTHEAST...PERHAPS INDICATIVE OF THE GENERAL LACK OF ORGANIZATION AT THIS TIME. IN ANY EVENT...SATELLITE CLASSIFICATIONS REMAIN BELOW TROPICAL STORM STRENGTH AND THE INITIAL INTENSITY WILL STAY AT 30 KT. FOR THE MOMENT...WITH THE CENTER ON THE NORTHERN PART OF THE CONVECTIVE MASS...ANY INTENSIFICATION IS TEMPORARILY HALTED. HOWEVER WATER VAPOR IMAGES SHOW THAT THE DEPRESSION IS UNDER THE INFLUENCE OF UPPER RIDGING WITH ONLY MODEST SOUTHEASTERLY SHEAR. THIS PATTERN SHOULD ALLOW FOR MORE STRENGTHENING LATER ON AS A LOW TO MODERATE SHEAR ENVIRONMENT IS FORECAST TO PERSIST FOR AT LEAST 3 DAYS BY THE GLOBAL MODELS. IN ADDITION...SSTS WILL REMAIN PLENTY WARM...SO INTENSIFICATION IS FORECAST. THE ONLY OBVIOUS NEGATIVE FOR FURTHER DEVELOPMENT IS THE ENTRAINMENT OF MORE STABLE AIR INTO THE NORTHERN PORTION OF THE CIRCULATION...WHICH SHOULD BE MINIMIZED IF THE CYCLONE CONTINUES MOVING WESTWARD. VERTICAL WIND SHEAR COULD INCREASE BEYOND THREE DAYS SO THE INTENSITY FORECAST WILL BE NUDGED DOWNWARD AT THAT TIME-FRAME. THE INITIAL MOTION ESTIMATE IS WESTWARD...270/4. A MIDDLE- TO UPPER-LEVEL TROUGH OVER MEXICO HAS PASSED THE DEPRESSION AND LEFT IT IN AN AREA OF WEAK STEERING CONDITIONS. RIDGING TO THE NORTHWEST OF THE SYSTEM SHOULD STEER IT SLOWLY WESTWARD FOR A COUPLE DAYS. THEREAFTER...UPPER RIDGING IS FORECAST TO BUILD TO THE NORTH OF THE DEPRESSION...WHICH SHOULD ENCOURAGE A FASTER WESTWARD MOTION. THIS IS THE APPROXIMATE SOLUTION PRESENTED BY THE ECMWF AND THE CANADIAN MODEL. HOWEVER... OTHER GLOBAL MODELS HAVE SLOWER SOLUTIONS... SEEMINGLY STRUGGLING WITH AN AREA OF DISTURBED WEATHER TO THE EAST OF THE DEPRESSION. THE GFS... NOGAPS AND UKMET (TO SOME EXTENT) FORECAST THAT THE SYSTEM BEHIND THE DEPRESSION WILL BECOME LARGER AND STRONGER RATHER QUICKLY... WHICH SLOWS THE MOTION OF THE DEPRESSION. FOR NOW...GIVEN THE RELATIVE BENIGN APPEARANCE ON SATELLITE OF THE SECOND SYSTEM...A FASTER SOLUTION WILL BE FAVORED. THE OFFICIAL FORECAST IS SLOWER THAN THE PREVIOUS FORECAST PACKAGE BUT FASTER THAN MOST OF THE GUIDANCE. FORECAST POSITIONS AND MAX WINDS INITIAL 27/0900Z 12.8N 111.2W 30 KT 12HR VT 27/1800Z 12.8N 111.8W 30 KT 24HR VT 28/0600Z 12.8N 112.6W 40 KT 36HR VT 28/1800Z 12.8N 113.4W 45 KT 48HR VT 29/0600Z 12.8N 114.2W 50 KT 72HR VT 30/0600Z 12.8N 116.0W 55 KT 96HR VT 31/0600Z 12.8N 118.0W 55 KT 120HR VT 01/0600Z 12.8N 120.5W 50 KT $$ FORECASTER BLAKE