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PUBLIC INFO. STATEMENT...SERVICE CHANGE NOTICE 00-43...UPDATED
NATIONAL WEATHER SERVICE HEADQUARTERS WASHINGTON DC
900 AM EDT THU MAY 11 2000
...REISSUED WITH NEW TITLE ...EXCESSIVE HEAT OUTLOOK PRODUCT.
APPARENT TEMPERATURE IS NOW REFERRED TO AS THE HEAT INDEX
TEMPERATURE. ALSO PROBABILITY - RATHER THAN PROBABILITY ANOMALY
- WILL BE USED FOR THE HEAT INDEX PROBABILISTIC FORECASTS.
TO: NATIONAL WEATHER SERVICE EMPLOYEES...NOAAPORT
SUBSCRIBERS... NWS EMPLOYEES...AND OTHER NWS CUSTOMERS
FROM: ROBERT E. LIVEZEY
CHIEF...CLIMATE SERVICES DIVISION
SUBJECT: NEW EXCESSIVE HEAT OUTLOOK PRODUCTS...EFFECTIVE JUNE 1
2000
ON THURSDAY...JUNE 1 2000...THE CLIMATE PREDICTION CENTER /CPC/
WILL START PROVIDING EXCESSIVE HEAT OUTLOOKS. THE OUTLOOKS WILL
BE ISSUED DAILY AROUND 4:00 PM EASTERN LOCAL TIME. THE OUTLOOKS
WILL EMPHASIZE DAILY MEAN HEAT INDEX TEMPERATURES RATHER THAN
DAILY MAXIMUM HEAT INDEX...ALTHOUGH CPC ALSO WILL PROVIDE THE
EXPECTED VALUE OF THE MAXIMUM HEAT INDEX DURING THE 5- OR 7- DAY
FORECAST PERIOD AT APPROXIMATELY 200 LOCATIONS.
BECAUSE HEALTH RISKS VARY ENORMOUSLY FROM AREA TO AREA...CPC WILL
ISSUE FORECASTS OF THE PROBABILITY OF THE HEAT INDEX EXCEEDING
THREE DIFFERENT THRESHOLDS. THESE WILL BE OVERLAID ON ISOLINES OF
THE CLIMATOLOGICAL NORMAL PROBABILITY. CPC CHOSE THE THRESHOLD
HEAT INDEX VALUES BASED ON WHEN CUMULATIVE EXPOSURE WOULD BE
LIKELY TO CAUSE SIGNIFICANT HEALTH RISKS FOR A NUMBER OF THE MOST
VULNERABLE CITIES.
IN ADDITION...BECAUSE VULNERABILITY INCREASES WITH DURATION OF
THE HEAT WAVE...RISKS FOR EXCEEDING THE LOWER THRESHOLDS ARE FOR
DURATIONS LONGER THAN ONE DAY. THESE NEW PRODUCTS WILL CONSIST OF
MAPS OF THE PROBABILITY OF DAILY MEAN HEAT INDEX TEMPERATURE FOR
THRESHOLDS EQUAL TO OR GREATER THAN 85F... 90F... OR 95F FOR EACH
OF THE 3-7-... 6-10-... AND 8-14-DAY FORECAST PERIODS. THE
FORECASTS WILL BE FOR DIFFERENT MINIMUM NUMBERS OF DAYS WITHIN
THE 5 OR 7 DAY PERIOD OF THE FORECAST - NAMELY 3...2 AND 1 DAYS -
RESPECTIVELY - WHEN THE THRESHOLDS ARE EQUALED OR EXCEEDED.
MORE SPECIFICALLY...FOR THE 3-7-... 6-10- AND 8-14-DAY OUTLOOK
PERIODS - THE NEW PRODUCTS PREDICT THE PERCENT CHANCE OF EQUALING
OR EXCEEDING THE FOLLOWING CRITERIA:
A. DAILY AVERAGE HEAT INDEX EQUAL TO OR GREATER THAN 85F THREE
OR MORE DAYS IN THE FORECAST PERIOD
B. DAILY AVERAGE HEAT INDEX EQUAL TO OR GREATER THAN 90F TWO OR
MORE DAYS IN THE FORECAST PERIOD
C. DAILY AVERAGE HEAT INDEX TO OR GREATER THAN 95F ONE OR MORE
DAYS IN THE FORECAST PERIOD
THE WMO HEADINGS AND AWIPS IDENTIFIERS FOR THE NINE CHARTS ARE AS
FOLLOWS:
AV. HEAT INDEX 3-7 DAY 6-10 DAY 8-14 DAY
CRITERIA A PTAM90 KWNC PTAS90 KWNC PTAT90 KWNC
/85F+ FOR 3+DAYS/ RBGHI1 RBGHI4 RBGHI7
CRITERIA B PTAM95 KWNC PTAS95 KWNC PTAT95 KWNC
/90F+ FOR 2+DAYS/ RBGHI2 RBGHI5 RBGHI8
CRITERIA C PTAM00 KWNC PTAS00 KWNC PTAT00 KWNC
/95F+ FOR 1+DAY/ RBGHI3 RBGHI6 RBGHI9
NOTE - THE NUMBERS WITHIN THE WMO HEADINGS DO NOT COINCIDE WITH
THE HEAT INDEX THRESHOLDS.
THESE NINE CHARTS WILL BE ISSUED OVER AWIPS...NOAAPORT...AND THE
CPC INTERNET SITE - HTTP://WWW.CPC.NCEP.NOAA.GOV - USE LOWER CASE
FOR FURTHER INFORMATION...CONTACT
NOAA/NWS
CLIMATE PREDICTION CENTER - W/NP51
5200 AUTH RD.
CAMP SPRINGS MD 20746-4304
OR E-MAIL CPC THROUGH THEIR WEB SITE.
THIS AND OTHER NOTIFICATIONS ARE ON THE INTERNET AT:
WWW.NWS.NOAA/GOV/OM/NOTIF.HTM /USE LOWER CASE/
END
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