Sunday, July 03, 2005

Tropical Depression Three Update 040300Z At 10 PM CDT the center of Tropical Depression Three was at 18.9N 87.5W, 60 miles east of Chetumal, Mexico and moving to the northwest at 9 mph.  Winds remain near 35 mph and pressure has fallen to 1006 mb (29.71"). Tropical Depression Three Advisory Number Two The system may be at tropical storm strengh now, but as there aren't any surface (or hurricane hunter) observations to support that, intensity is being kept at tropical depression strength for now.  The forecast remains similar to that of the previous advisory (tropical storm making landfall in eastern Texas/western Louisiana). Tropical Depression Three Discussion Number Two There has been quite a burst of thunderstorm activity in the vicinity of the center of the storm.  As the discussion notes, if this activity is sustained, then this system is a tropical storm.  Aside from a couple of surface observation stations and satellite, there won't be much new data on this storm for a while as the next hurricane hunter isn't scheduled to be in the area until tomorrow afternoon. 2005 Hurricane Season, Weather comment []11:01:04 PM   trackback []

Tropical Depression Three Update 040000Z At 7 PM CDT, the center of Tropical Depression Three was at 18.6N 87.2W, 85 miles east of Chetumal, Mexico.  Movement is to the west-northwest at four mph.  Winds remain near 35 mph and pressure has fallen to 1007 millibars (29.74").  A Tropical Storm Watch has been issued for the eastern part of the Yucatan Peninsula. Tropical Depression Three Intermediate Advisory 1A While the hurricane hunters have not found increased winds, they have found pressure to be dropping.  The center of circulation at the surface seems to be shifting to the northeast slightly as the system better organizes itself.  It is a bit disconcerting that this process is happening off-shore as it implies that it could make landfall as a tropical storm (and therefore be stronger than forecast down the line).  A very dynamic situation at the moment; it may not stabilize by the time the next full package of advisories comes around (10 PM CDT).  The forecasters are going to be doing more nowcasting (i.e. responding to current observations) then looking ahead on that advisory, because the next set of global forecast model runs will only be just beginning at the time the advisories go out.  The forecasters won't have a real chance to include their output in the forecast until 4 AM CDT (and even then, if the models persist in not initializing with the system in place, the models won't be of much help). It's going to be an interesting evening... 2005 Hurricane Season, Weather comment []8:10:16 PM   trackback []

Tropical Depression Three At 4 PM CDT, the center of Tropical Depression Three was estimated to be at 18.4N 87.1W, which is 80 miles east of  Chetumal, Mexico.  Movement is to the west-northwest at eight knots, maximum sustained winds are near 35 knots, and minimum central pressure is 1009 millibars (29.80") Tropical Depression One Advisory Number 1 The  hurricane hunter managed to find a closed center of circulation (necessary for a system to be called a tropical depression).  Surface observations support that idea as well.  Strenghening is not expected until the depression crosses the Yucatan and gets into the Gulf of Mexico.  The forecast models aren't strengthening the storm any, however, since conditions appear to be favorable, the official forecast has a respectable amount of strengthening as the storm makes its way to the coast of eastern Texas. Tropical Depression Three Discussion Number 1 It will be interesting to see how the models initialize tonight (i.e. how well do they represent the system before the forecast starts).  I suspect the reason why they aren't doing anything with the depression presently; they aren't picking it up accurately to start with. The area of low pressure seems to be very broad compared to that of Bret; the latest observation from Chetumal showed a pressure of 1010 millibars.  If the forecast is correct, we will have the thrid tropical storm of the season by Tuesday morning. 2005 Hurricane Season, Weather comment []5:21:50 PM   trackback []

Tropical Depression Three forms SPECIAL TROPICAL DISTURBANCE STATEMENT NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 415 PM EDT SUN JUL 3 2005 REPORTS FROM AN AIR FORCE RESERVE RECONNAISSANCE AIRCRAFT INDICATE THE AREA OF DISTURBED WEATHER CENTERED JUST EAST OF THE YUCATAN PENINSULA HAS DEVELOPED INTO TROPICAL DEPRESSION THREE...AND ADVISORIES WILL BE INITIATED AT 4 PM CDT...OR 2100Z. SINCE THE DEPRESSION IS NOT EXPECTED TO REACH TROPICAL STORM STRENGTH BEFORE IT MAKES LANDFALL ALONG THE EAST COAST OF THE YUCATAN PENINSULA LATER TONIGHT...NO WATCHES OR WARNINGS ARE ANTICIPATED AT THIS TIME. FORECASTER STEWART/PASCH 2005 Hurricane Season, Weather comment []4:23:12 PM   trackback []

Tropics Watch 0703 This is the area of interest this afternoon. A hurricane hunter has been launched to investigate the area and will be on station by 2000Z (4 PM EDT). The latest Tropical Weather Discussion describes it thusly: W CARIBBEAN TROPICAL WAVE EXTENDS FROM THE YUCATAN CHANNEL INTO NW HONDURAS WITH A 1010 MB LOW NEAR 19N86W MOVING WNW 10 KT. THE LOW CONTINUES TO GET BETTER ORGANIZED WITH BANDING FEATURES BECOMING MORE PROMINENT IN THE SOUTHERN SEMICIRCLE AND A LARGE ANTICYCLONE ALOFT PROVIDING A FAVORABLE ENVIRONMENT FOR FURTHER DEVELOPMENT. BUOY 42056 JUST REPORTED A SUSTAINED WIND OF 31 KT TO THE NE OF THE CENTER. A LARGE AREA OF TSTMS HAS DIED DOWN SOMEWHAT IN THE PAST 3 HOURS BUT WIDELY SCATTERED MODERATE CONVECTION REMAINS OVER THE NW CARIBBEAN N OF 16N W OF 80W WITH HEAVY RAINS MOVING OVER W CUBA AND THE ISLE OF PINES. THIS SYSTEM IS LIKELY TO MOVE OVER YUCATAN OVERNIGHT AND BRING VERY HEAVY RAIN... EMERGING INTO THE GULF OF MEXICO LATE MON/EARLY TUE. THIS LOW HAS THE POTENTIAL TO BECOME A TROPICAL CYCLONE WITHIN THE NEXT DAY OR TWO. Track forecasting is difficult at the moment, because it is difficult to determine where the center of circulation is. The hurricane hunter will be quite helpful in pinning that down. The above National Hurricane Centerdiscussion places the center at 19N 86W; the latest estimate from the Satellite Services division places it at 19.6N 85.1W; a significant difference. As far as intensity goes, that is also another thing that we will have to wait and see what the hurricane hunter finds. There are a couple of buoys in the region, but if the estimates of the center are correct, it didn't pass over either of them. Also, while there are a few observation stations on the Yucatan, the system isn't close enough yet for them to be giving indications of its state. Conditions are quite favorable for development as their is little shear in the region and Sea Surface Temperatures are as warm as one would expect for the Gulf of Mexico. I'll post an update as the hurricane hunter gets on station and observations from the area come in (approximately 4:30 EDT). 2005 Hurricane Season, Weather comment []2:35:31 PM   trackback []