[MTHOLLYSVRWX] Public Information Statement : PHI@ 9/2/2009 5:11:01 PM

[svrwx at wx3i.net]

NOUS41 KPHI 022109
PNSPHI
DEZ001>004-MDZ008-012-015-019-020-NJZ001-007>010-012>027-PAZ054-
055-060>062-067>071-031200-

PUBLIC INFORMATION STATEMENT
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
509 PM EDT WED SEP 2 2009

...EXPANDED AREA WEATHER RECORDS...

THE NATIONAL CLIMATIC DATA CENTER (NCDC) AND THE NORTHEAST
REGIONAL CLIMATE CENTER (NRCC) HAVE BEEN WORKING TO ENHANCE AND/OR
EXPAND WEATHER RECORDS AT AREAS CENTERED AT SELECTED CITIES AROUND
THE NATION. THE PROJECT IS CALLED THE THREADEX PROJECT. THE FOUR
AREAS IN OUR REGION THAT HAVE BEEN OR ARE BEING WORKED ON ARE THE
ALLENTOWN AREA, THE ATLANTIC CITY AREA, THE PHILADELPHIA AREA AND
THE WILMINGTON AREA.

THE GENERAL APPROACH FOR A GIVEN AREA THAT NCDC AND NRCC HAVE 
ADOPTED IS AS FOLLOWS:  THEY START BY TRACING BACK AS LONG AS 
POSSIBLE THE DATA FROM THE PRIMARY SITE WHERE DATA CURRENTLY ARE 
BEING COLLECTED.  THEY REFER TO THIS AS A DATA THREAD, AND HENCE THE 
NAME THREADEX.  WHEN THAT THREAD TERMINATES, THEY ASSESS OTHER SITES 
IN THE AREA WHERE DATA WERE BEING COLLECTED AT THE TERMINATION TIME 
AND SELECT FROM THOSE SITES THE ONE WHERE THE THREAD GOES BACK 
FURTHEST.  THEY FOLLOW THAT THREAD BACK UNTIL IT TERMINATES.  THEY 
THEN REPEAT THE PROCESS UNTIL THERE ARE NO FURTHER DATA THREADS FROM
THE AREA.  

BECAUSE THESE ENHANCED AND/OR EXPANDED WEATHER RECORDS WILL BE USED 
IN OUR LOCAL CLIMATE PRODUCTS, WE AT YOUR LOCAL NATIONAL WEATHER 
SERVICE FORECAST OFFICE HAVE WORKED IN CONJUNCTION WITH NCDC AND 
NRCC TO TRY TO ENSURE THAT THE INTEGRITY OF THE DATA RECORDS HAVE 
BEEN MAINTAINED.  HOWEVER, PLEASE NOTE THAT NCDC AND NRCC DO NOT 
ASSESS MULTIPLE THREADS AT ANY SINGLE POINT IN TIME.  RAMIFICATIONS 
OF THIS ARE:

THERE MAY BE, FOR EXAMPLE, A DAILY MAXIMUM TEMPERATURE FROM AN 
ALTERNATE SITE IN THE ALLENTOWN AREA THAT EXCEEDS THE DAILY RECORD 
DETERMINED FROM THE CHOSEN THREAD.  THAT MAXIMUM TEMPERATURE FROM 
THE ALTERNATE SITE WILL NOT BE CONSIDERED A RECORD MAXIMUM.   

IF THE THREAD SELECTED FOR A GIVEN TIME IS NOT FROM THE SAME SITE 
WHERE A PREVIOUSLY ESTABLISHED RECORD OCCURRED, THEN THAT RECORD 
LIKELY WILL CHANGE. 

FINALLY, THE RESULTING RECORDS MAY NOT BE FIT FOR SCIENTIFIC 
RESEARCH, BECAUSE THE DIFFERENCES IN THE SPECIFIC SITES FROM WHICH 
THE COMPONENT THREADS COME MAY INTRODUCE FACTORS OTHER THAN CLIMATE 
CHANGE THAT CONTAMINATE THE RECORDS (CHANGES IN ELEVATION, CHANGES 
IN LOCATION RELATIVE TO HIGHLY URBANIZED PARTS OF THE AREA OR BODIES 
OF WATER, ETC.).  DATA FOR RESEARCH STUDIES SHOULD BE OBTAINED FROM 
NCDC OR NRCC DIRECTLY. 

YOU MAY VIEW THE SITES USED FOR THE RECORDS FOR EACH AREA BY GOING 
TO:  HTTP://THREADEX.RCC-ACIS.ORG, SELECTING THE AREA OF INTEREST 
UNDER THE "VIEW RECORDS FOR" OPTION AND SELECTING "STATION THREAD" 
UNDER THE "VARIABLE" OPTION.  

PLEASE DO NOT ADDRESS ANY COMMENTS OR QUESTIONS REGARDING THREADEX 
TO EITHER NCDC OR NRCC.  RATHER, ADDRESS ANY COMMENTS OR QUESTIONS 
TO US BY GOING TO:  HTTP://WWW.WEATHER.GOV/PHI AND SELECTING THE 
"CONTACT US" OPTION AT THE BOTTOM OF THE PAGE. 

$$

MPD