950616-NOUS41 (fwd)

• To: nws-changes@xxxxxxxxxxxxxxxx
• Subject: 950616-NOUS41 (fwd)
• From: Linda Miller <lmiller@xxxxxxxxxxxxxxxx>
• Date: Fri, 16 Jun 1995 14:31:08 -0600 (MDT)

966 

NOUS41 KWBC 161933

PNSNMC



NATIONAL TECHNICAL INFORMATION MESSAGE 95-22

NATIONAL WEATHER SERVICE HEADQUARTERS

0330 PM EDT FRI JUN 16 1995



TO:       USERS OF AFOS GRAPHICS



FROM:     PAUL DALLAVALLE

          CHIEF... SYNOPTIC-SCALE TECHNIQUES BRANCH



SUBJECT:  NGM-BASED THUNDERSTORM AND SEVERE LOCAL STORM           

          PROBABILITY FORECASTS FOR THE CONUS



     EFFECTIVE WITH THE 1200 UTC CYCLE ON JUNE 21... 1995... THE

NATIONAL WEATHER SERVICE WILL OPERATIONALLY IMPLEMENT NEW

GRAPHICS PRODUCTS THAT CONTAIN NGM-BASED MOS PROBABILITY

FORECASTS OF THUNDERSTORMS AND SEVERE LOCAL STORMS FOR THE

CONTERMINOUS U.S.  THESE PRODUCTS WILL BE DISTRIBUTED ON AFOS

WITH THE FOLLOWING IDENTIFIERS...  

                       

                        1200 UTC

NMCGPH02G -  6-24 H UNCONDITIONAL THUNDERSTORM PROBABILITY

NMCGPH02O -  6-24 H CONDITIONAL SEVERE LOCAL STORM PROBABILITY

NMCGPH03G - 24-48 H UNCONDITIONAL THUNDERSTORM PROBABILITY

NMCGPH03O - 24-48 H CONDITIONAL SEVERE LOCAL STORM PROBABILITY



                        0000 UTC



NMCGPH0TG - 12-36 H UNCONDITIONAL THUNDERSTORM PROBABILITY

NMCGPH0TO - 12-36 H CONDITIONAL SEVERE LOCAL STORM PROBABILITY

NMCGPH05G - 36-60 H UNCONDITIONAL THUNDERSTORM PROBABILITY

NMCGPH05O - 36-60 H CONDITIONAL SEVERE LOCAL STORM PROBABILITY



     THE THUNDERSTORM FORECASTS GIVE THE UNCONDITIONAL

PROBABILITY OF TWO OR MORE CLOUD-TO-GROUND LIGHTNING FLASHES

OCCURRING IN GRID BLOCKS THAT ARE 48-KM ON A SIDE.  IN

CONTRAST... THE SEVERE LOCAL STORM EQUATIONS GIVE THE CONDITIONAL

PROBABILITY OF TORNADOES... LARGE HAIL... AND/OR DAMAGING WINDS

GIVEN THE OCCURRENCE OF A THUNDERSTORM (DEFINED AS TWO OR MORE

CLOUD-TO-GROUND LIGHTNING FLASHES IN A GRID BLOCK).





     TECHNICAL PROCEDURES BULLETIN #419 DESCRIBES THE NEW NGM-

BASED THUNDERSTORM AND SEVERE LOCAL STORM PRODUCTS.  IF YOU NEED

FURTHER INFORMATION ON THE PRODUCTS... PLEASE CALL RON REAP OF

THE TECHNIQUES DEVELOPMENT LABORATORY AT (301) 713-1772... OR

WRITE TO HIM AT...



NOAA/NATIONAL WEATHER SERVICE

TECHNIQUES DEVELOPMENT LABORATORY... W/OSD21

1325 EAST-WEST HWY 10380

SILVER SPRING... MD  20910



END