ZCZC MIATCDEP3 ALL TTAA00 KNHC DDHHMM TROPICAL DEPRESSION MARTY DISCUSSION NUMBER 21 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 8 PM PDT TUE SEP 23 2003 SATELLITE IMAGERY AND WSR-88D RADAR DATA FROM YUMA ARIZONA INDICATE THAT MARTY HAS BECOME A LITTLE BETTER ORGANIZED THIS EVENING...EVEN THOUGH CONVECTIVE CLOUD TOPS HAVE WARMED SIGNIFICANTLY. THE YUMA RADAR INDICATES A NEW BAND HAS DEVELOPED TO THE SOUTHWEST AND IS WRAPPING EASTWARD AROUND THE SOUTHERN SEMICIRCLE...WITH CELL MOTION APPROACHING 40 KT. OTHER NEW CONVECTION OF 40-45 DBZ HAS DEVELOPED NEAR THE CENTER...WITH A LARGE FIELD OF 30-40DBZ ECHOES LOCATED IN THE NORTHERN SEMICIRCLE. IN ADDITION... DOPPLER VELOCITIES OF 35-40 KT BETWEEN 9000 AND 11000 FT ARE INDICATED JUST NORTHEAST OF THE CENTER...WHICH SUGGESTS THAT THERE IS PROBABLY AT LEAST 30 KT AT THE SURFACE. SATELLITE INTENSITY ESTIMATES OF 35/30/30 FROM TAFB/SAB/AFWA ALSO SUPPORT AN INTENSITY OF 30 KT...ALBEIT LIKELY OVER JUST A VERY SMALL AREA IN THE NORTHEAST QUADRANT. THE INITIAL MOTION ESTIMATE IS 345/06. MARTY HAS ACTUALLY BEEN MOVING AT 8-9 KT DURING THE PAST 6 HOURS...BUT THE LAST COUPLE OF HOURS OF YUMA RADAR DATA SUGGESTS THAT MARTY IS MOVING A LITTLE SLOWER. THE NHC MODEL GUIDANCE IS ALL OVER THE COMPASS...WHICH USUALLY SUGGESTS SLOW OR NO FORWARD SPEED. THE BIG QUESTION IS WILL THE SURFACE CENTER MOVE INLAND. MOST OF THE MODEL GUIDANCE SAYS NO AND THEY KEEP THE REMNANT CIRCULATION OVER THE GULF OF CALIFORNIA. HOWEVER...THIS MAY BE AN ARTIFACT OF THE VORTEX TRACKER SINCE SOME OF THE GLOBAL MODELS BRING THE 850 MB CENTER JUST INLAND OVER EXTREME NORTHWESTERN MAINLAND MEXICO IN ABOUT 12 HOURS. MOST OF THE NHC MODELS ALSO TAKE THE 500 MB CENTER INLAND NEAR EXTREME SOUTHWESTERN ARIZONA AND THEN TURN IT WESTWARD. THE OFFICIAL FORECAST MOVES MARTY SLOWLY NORTHWARD AND INLAND IN ABOUT 12 HOURS OR SO BEFORE TURNING IT SLOWLY NORTHWESTWARD. THIS IS BASED ON THE PREMISE THAT THE CIRCULATION WILL REMAIN DEEP ENOUGH...AS SUGGESTED BY RADAR IMAGERY...AND GET PUSHED NORTHWARD BY THE DEEP SOUTHERLY FLOW ON THE EAST SIDE OF LOW PRESSURE SYSTEM LOCATED IN WATER VAPOR IMAGERY ABOUT 650 NMI WEST OF SAN DIEGO. AFTER MOVING INLAND... MARTY SHOULD RAPIDLY WEAKEN INTO A REMNANT LOW...IF NOT SOONER. LOCALLY HEAVY RAINFALL APPEARS LIKELY OVER NORTHWESTERN MAINLAND MEXICO...THE NORTHEASTERN BAJA PENINSULA...AND EXTREME SOUTHERN ARIZONA APPEARS LIKELY GIVEN THE RELATIVELY SLOW FORWARD SPEED AND INCREASING UPPER-LEVEL DIFLUENCE. COORDINATION WITH WFO PHOENIX INDICATES THAT RAINFALL TOTALS OF 2 TO 4 INCHES OVER SOUTHWESTERN ARIZONA TONIGHT AND TOMORROW MORNING MAY APPROACH FLASH FLOOD GUIDANCE VALUES. FORECASTER STEWART FORECAST POSITIONS AND MAX WINDS INITIAL 24/0300Z 30.9N 113.9W 30 KT 12HR VT 24/1200Z 31.4N 114.0W 25 KT...DISSIPATING 24HR VT 25/0000Z 31.8N 114.2W 20 KT...DISSIPATING INLAND 36HR VT 25/1200Z 32.3N 114.4W 20 KT...REMNANT LOW INLAND 48HR VT 26/0000Z...DISSIPATED INLAND NNNN
Alternate Formats
About Alternates -
E-Mail Advisories -
RSS Feeds
Cyclone Forecasts
Latest Advisory -
Past Advisories -
About Advisories
Marine Forecasts
Latest Products -
About Marine Products
Tools & Data
Satellite Imagery -
US Weather Radar -
Aircraft Recon -
Local Data Archive -
Forecast Verification -
Deadliest/Costliest/Most Intense
Learn About Hurricanes
Storm Names
Wind Scale -
Prepare -
Climatology -
NHC Glossary -
NHC Acronyms -
Frequently Asked Questions -
AOML Hurricane-Research Division
About Us
About NHC -
Mission/Vision -
Other NCEP Centers -
NHC Staff -
Visitor Information -
NHC Library
NOAA/
National Weather Service
National Centers for Environmental Prediction
National Hurricane Center
11691 SW 17th Street
Miami, Florida, 33165-2149 USA
nhcwebmaster@noaa.gov
Disclaimer
Privacy Policy
Credits
About Us
Glossary
Career Opportunities
Page last modified: Monday, 07-Feb-2005 16:49:59 UTC